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Journal of Environmental Management 145 (2014) 210e229

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Journal of Environmental Management

journal homepage: www.elsevier .com/locate/ jenvman

Review

Implications of stillage land disposal: A critical review on the impactsof fertigation

Lucas Tadeu Fuess a, *, Marcelo Loureiro Garcia b, 1

a Laboratory of Biological Processes, S~ao Carlos School of Engineering (EESC), University of S~ao Paulo (USP), 1100 Jo~ao Dagnone Avenue, 13563-120 S~aoCarlos, SP, Brazilb Institute of Geosciences and Exact Sciences, UNESP e Univ Estadual Paulista, 1515 24-A Avenue, 13506-900 Rio Claro, SP, Brazil

a r t i c l e i n f o

Article history:Received 11 April 2014Received in revised form1 July 2014Accepted 3 July 2014Available online

Keywords:Ethanol productionStillageFertigationAdverse impactsToxic metals

* Corresponding author. Tel.: þ55 16 3419 4061.E-mail addresses: ltfuess@sc.usp.br, lt_fuess@

mlgarcia@rc.unesp.br (M.L. Garcia).1 Tel.: þ55 19 3526 9277.

http://dx.doi.org/10.1016/j.jenvman.2014.07.0030301-4797/© 2014 Elsevier Ltd. All rights reserved.

a b s t r a c t

Stillage is the main wastewater from ethanol production, generated specifically in the step of distillation.Regardless the feedstock, stillage contains high concentrations of organic matter, potassium and sulfates,as well as acidic and corrosive characteristics. Currently almost the entire volume of stillage generated inBrazilian distilleries is directed to the fertigation of sugarcane fields, due to its fertilizer character.However, the polluting potential of stillage characterizes its land disposal as problematic, consideringprobable negative impacts on the soil structure and water resources in case of excessive dosages. Sincethe literature lacks critical content describing clearly the cons related to the reuse of stillage in agri-culture in the long-term, this review aimed to assess the real polluting potential of stillage, and theimplications of its land disposal and/or discharge into water bodies. Evidence from the literature indicatethat the main obstacles to reuse stillage in natura include risks of soil salinization; clogging of pores,reduction in the microbial activity and the significant depletion of dissolved oxygen concentrations inwater bodies; contamination per nitrates and eutrophication; soil structure destabilization due to highconcentrations of potassium and sodium; and, possible acidification of soil and water resources,considering the low pH of stillage (~4,5). Toxic metals, such as cadmium, lead, copper, chromium andnickel, were also identified in concentrations above the recommended limits in stillage samples,increasing risks to human health (e.g. carcinogenic potential) and to crops (e.g. productivity loss). Inshort, although some studies report benefits from the land application of stillage, its treatment prior todisposal is essential to make fertigation an environmentally suitable practice.

© 2014 Elsevier Ltd. All rights reserved.

1. Introduction

Ethanol represents one of the main alternative energy sourcesdeveloped in the attempt to reduce the dependence on fossil fuels,whose trade often faces political and economical barriers due to theinstability in the major oil-producing countries (Gunaseelan, 1997;Pant and Adholeya, 2007; B�aez-V�asquez and Demain, 2008). Themain uses of ethanol regard the automotive industry, so that incomparisonwith other technologies employed in the production ofbiofuels some important advantages may be highlighted. Firstly wepoint out the technological consolidation of ethanol worldwide, aswell as the large variety of convertible raw materials that can beproduced in different climatic conditions (Wilkie et al., 2000; Hill

hotmail.com (L.T. Fuess),

et al., 2006; BNDES and CGEE, 2008; Cavallet et al., 2012). Addi-tionally, some important environmental benefits result from itsproduction and use: a renewable character, due to its biologicalorigin (Hill et al., 2006), and an intrinsic potential to reduce theemission of greenhouse gases, based on carbon sequestration bythe crops and on cleaner combustion (BNDES and CGEE, 2008;Macedo et al., 2008; Khatiwada and Silveira, 2011). However, theholistic characterization of ethanol as a self-sustaining technologyalso depends on the proper management of stillage, the mainwastewater from distilleries.

Stillage, also named vinasse or distillery wastewater, is a dark-brown high-strength wastewater (HSW) whose organic contentmay be 100 times higher than the ones found in domestic sewage. Italso presents acidic and corrosive characteristics, as well asappreciable concentrations of macro- andmicronutrients (Pant andAdholeya, 2007; Strong and Burgess, 2008; Mohana et al., 2009;Espa~na-Gamboa et al., 2011; Fuess and Garcia, 2013). Regardlessthe feedstock used, ethanol plants usually generate 10e15 L of

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 211

stillage per liter of produced ethanol (Pant and Adholeya, 2007;Satyawali and Balakrishnan, 2008; Mohana et al., 2009; Oliveiraet al., 2013). Assuming an average rate of 13 L of stillage per literof ethanol (BNDES and CGEE, 2008; Wilkie et al., 2000), a singlerelatively large-scaled distillery (365,000 m3 per year, Dias et al.,2011) could produce annually up to 4.7 billion liters of stillage.

The available technological approaches applied to the manage-ment and/or treatment of stillage include mainly evaporation andconcentration to produce animal feed and return to agriculturalfields through fertigation, which have been used extensively overthe last decades (Sheehan and Greenfield, 1980; Willington andMarten, 1982; Macedo, 2005; Pimentel et al., 2007; Smeets et al.,2008; Christofoletti et al., 2013). Currently several works describethe application of treatment technologies aiming at reducing thepolluting load of stillage, which include: [i] anaerobic and aerobicconventional processes (Wilkie et al., 2000; Nandy et al., 2002; Pantand Adholeya, 2007; Acharya et al., 2008; Agler et al., 2008;Satyawali and Balakrishnan, 2008; Tondee et al., 2008; Mohanaet al., 2009; Ferreira et al., 2011; Robles-Gonz�alez et al., 2012); [ii]phytoremediation (Billore et al., 2001; Valderrama et al., 2002;Singh et al., 2005; Olguín et al., 2008; Sohsalam andSirianuntapiboon, 2008); [iii] conventional physicochemicalmethods (e.g. adsorption and coagulationeflocculation) (Zayaset al., 2007; Ryan et al., 2008; Liang et al., 2009, 2010; Rodrigueset al., 2013); and even [iv] advanced oxidative processes (Sangaveand Pandit, 2004, 2006; Sangave et al., 2007; Yavuz, 2007;Asaithambi et al., 2012). However, most of the available data stillrefer to bench-scale systems, so that special attention should begiven to pilot- and full-scale plants, in order to investigate the realpotential applications of such technologies to stillage. Additionalapproaches for the management of stillage include its use as asource of nutrients in soil bioremediation (Mariano et al., 2009;Crivelaro et al., 2010; Christofoletti et al., 2013) and cultivation ofmicroalgal biomass (Dou�skov�a et al., 2010; Yen et al., 2012).

Focusing on the conventional methods of concentration andfertigation, some considerations should bemade. The production ofanimal feed through stillage concentration comprises the maintechnological approach to manage stillage used in the corn-to-ethanol industry from USA (Agler et al., 2008; Cassidy et al.,2008). In short, the liquid fraction remaining from distillation(whole stillage) is firstly separated from the insoluble solid fraction,usually through centrifugation. The solids are then dried to 10e12%,in order to produce distillers dried grains with solubles (DDGS),which present increased shelf-life, as well as high concentrations ofsoluble proteins (33% w/w), raw fat, fibre and elements such asphosphorus and potassium (Liu et al., 2008; Nichols et al., 2008;Espa~na-Gamboa et al., 2011). Although some calculations indicatean energy output from DDGS production and use of approximately1.86 MJ LEtOH�1 (Pimentel et al., 2007), due to the energy savings inconventional animal feed production processes, themain limitationassociated with the concentration of stillage still comprises thehigh energy consumption. In this case, water removal demandsenergy amounts as high as 2.88 GJ (800 kWh) for each ton ofevaporated water (Murphy and Power, 2008).

Considering fertigation, although some benefits should behighlighted, such as the reductions in the use of fresh water andmineral fertilizers (Macedo, 2005; BNDES and CGEE, 2008; Smeetset al., 2008), the direct land application of stillage may be prob-lematic, since its low pH and high concentrations of sulfate andorganic matter may compromise the soil structure and the sur-rounding water bodies, besides reducing crop productivity (Pantand Adholeya, 2007; Mohana et al., 2009). In Brazil most of thestillage is directly recycled through fertigation. This scenario isadequately represented by the ethanol industry in the State of S~aoPaulo, which concentrates 55% of the Brazilian ethanol plants and

where only 8 out of 165 distilleries employ alternative processes,such as anaerobic digestion, to manage stillage (Cruz, 2011). Inglobal terms, the volume of stillage annually disposed on theground may reach up to 325 billion liters in Brazil (Fuess, 2013).Considering the organic load supplied to the soil, each hectaremight receive about 4.2 tons of organic matter (as chemical oxygendemand e COD) in sugarcane crops e based on an average rate forthe application of stillage equal to 140 m3 ha�1 (BNDES and CGEE,2008), as well as on an average COD of 30 g L�1 (Wilkie et al., 2000;Fuess, 2013) for stillage. Furthermore, although scarcely quantified,side effects from the illegal discharge of stillage into water bodiesshould be considered, especially the depletion in the concentra-tions of dissolved oxygen.

Despite the adverse effects potentially associated with ferti-gation, the literature does not present a critical content thatclearly assesses such impacts. In fact, a few works describe someimpacts, usually positive ones (Pathak et al., 1999; Jain et al., 2005;Kaushik et al., 2005; Hati et al., 2007; Jiang et al., 2012; Previnaand Saravanan, 2013; Silva et al., 2014), resulting from using stil-lage as a fertilizer. However, most of the experiments are con-ducted in the short-term (i.e. 2e3 years), so that the literature(regarding technical and legal aspects) still lacks consistent datarelating the cons from reusing stillage in agriculture in the long-term. In this context, the main objective of this review was toassess the polluting potential of stillage, in order to point out theimplications of its improper land disposal and/or discharge intowater bodies. Data from literature were compiled and scenariosregarding the fate of stillage in environment were discussed.Finally, some alternatives for the proper management of stillagewere assessed, with emphasis on the energy generation prior to itsland disposal.

2. Stillage characterization: qualitative and quantitativeaspects

Ethanol production, regardless the feedstock, is roughly sum-marized in two basic processes, which comprise the fermentationof the sugar source and the distillation of the alcoholic mediaformed during the fermentative process. Stillage is generated spe-cifically in the distillation step, so that each type of unit processesand operations used to produce ethanol results in specific quali-tative characteristics for stillage (Satyawali and Balakrishnan, 2008;Mohana et al., 2009; Espa~na-Gamboa et al., 2011; Christofolettiet al., 2013). Another important factor is related to the feedstockprocessed. For instance, in production chains based on the pro-cessing of cereal grains, stillage usually presents a higher proteincontent, and as a consequence, a higher nitrogen content isobserved (Espa~na-Gamboa et al., 2011). In distilleries where sugar-based feedstocks are used, such as sugarcane, beet and sweet sor-ghum, high concentrations of sulfate are usually found in stillage(Fig. 1) (Ensinas et al., 2009), due to the broth's pH correction priorto fermentationwith sulfuric acid (H2SO4), mainly in cases based onthe use of molasses as feedstock. As a direct consequence, theconcentrations of sulfate tend to increase by the end of the sugar-cane season due to the continuous application of H2SO4 in thefermentation vessels.

Fig. 1 depicts the composition of stillages from different feed-stocks in comparison with domestic sewage. Besides the influenceof sulfuric acid, the low pH usually observed in stillage (~4.0e4.5) isstrictly related to the formation of organic acids during the step offermentation. Boopathy and Tilche (1991), de Bazúa et al. (1991)and Nasr et al. (2011) have reported volatile fatty acids concentra-tions of up 44.8, 18.8 and 12.3 g L�1 in stillages from beet molasses,sugarcane molasses and corn, respectively. Studies also have indi-cated the presence of significant amounts of phenolic (e.g. tannic

Fig. 1. Physicochemical composition of stillages from different feedstocks (values compiled from the reference literaturea). Notes: * Insufficient data to construct the boxplot;SGJ ¼ sugarcane juice; SGJM ¼ sugarcane juice þ molasses; CN ¼ corn; BM ¼ beet molasses; CV ¼ cassava. aReferences: Acharya et al. (2008), Agler et al. (2008), Alkan-Ozkaynakand Karthikeyan (2011), Andalib et al. (2012), Athanasopoulos (1987), Banu et al. (2006), Bianchi (2008), Boopathy and Tilche (1991), Bories et al. (1988), Braun and Huss (1982),Costa et al. (1986), Craveiro et al. (1986), de Bazúa et al. (1991), Driessen et al. (1994), Eskicioglu and Ghorbani (2011), Espinosa et al. (1995), Fernandes et al. (2010), Ferreira et al.(2011), Goyal et al. (1996), Harada et al. (1996), Hati et al. (2007), Jim�enez et al. (2003), Karhadkar et al. (1990), Kumar et al. (2007), Lee et al. (2011), Luo et al. (2009, 2010, 2011),Lutoslawski et al. (2011), Mariano et al. (2009), Nasr et al. (2011), Prada et al. (1998), Russo et al. (1985), S�anchez Riera et al. (1982, 1985), Seth et al. (1995), Sheehan and Greenfield(1980), Shivayogimath and Ramanujam (1999), Shrihari and Tare (1989), Siles et al. (2011), Souza et al. (1992), Stover et al. (1984), Tejada and Gonzalez (2005), Vlissidis andZouboulis (1993), Wiegant et al. (1985), Wilkinson (2011), Willington and Marten (1982) and Yeoh (1997).

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229212

and humic acids) compounds in stillages from sugar-based feed-stocks (Pant and Adholeya, 2007; Strong and Burgess, 2008;Mohana et al., 2009), which may reach up to 8000e10,000 mg/L(Acharya et al., 2008). The high color of stillage is usually attributedto this characteristic, in associationwith melanoidins fromMaillardreaction between sugars and proteins, and caramels from over-heated sugars (Pant and Adholeya, 2007; Wilkie et al., 2000;Espa~na-Gamboa et al., 2011). The occurrence of phenolic com-pounds in stillage comprises the partial degradation of lignocellu-losic structures, which are present on a residual portion of fibersremaining from the juice extraction in mills (Syaichurrozi et al.,2013). Since phenolic compounds and melonoidins present anti-oxidant characteristics, their presence may reduce or even inhibitthe microbial activity in the soil and/or aquatic environments (Pantand Adholeya, 2007; Mohana et al., 2009; Espa~na-Gamboa et al.,2011), in order to affect important natural biogeochemical cycles(e.g. carbon and nitrogen cycling). Such compounds may alsogenerate toxicity to microbial populations in biological reactorsapplied to the treatment of stillage (Parnaudeau et al., 2008).

Based on the high nutrient content found in stillage (Fig. 1), thereductions in the application of potassium (as potash e K2O) andphosphorus (as P2O5) in the fields throughmineral fertilizationmayreach up to 50 and 80% (CGEE, 2009), respectively, while for ni-trogen the average reduction is about 25% (Sivaloganathan et al.,2013). High concentrations of calcium (500e5000 mg L�1) andmagnesium (500e1500mg L�1) (Costa et al., 1986; Karhadkar et al.,1990; Banu et al., 2006) are also common in stillages, especially inthe streams from molasses-based distilleries (Ensinas et al., 2009),which enhances its fertilizing potential. Additional benefits fromusing stillage in agriculture in the short-term, as a direct result ofthe organic matter input, include:

1. Increase in the soil's potential in retaining water;2. Increase in the soil's cation-exchange capacity (CEC), which

improves its capacity in retaining and releasing nutrients to theplants, especially potassium, calcium and magnesium;

3. Improvement in the physical structure of the soil aggregates;and,

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 213

4. Enhancement in the microbial activity, so that the soil mayperform the role of a control volume to the treatment of efflu-ents. In this case, a greater microbial activity may increase thesoil's pH by consuming the acidity of stillage.

Sivaloganathan et al. (2013) have not observed significant al-terations in the pH of a sandy loam soil after dosing different di-lutions (1:10e1:50) of anaerobically treated sugarcane stillage intothe ground. In this case, pH levels were kept in the range of7.85e8.19, while in the control soil (i.e. without stillage application)the value was 8.38. pH values also have remained approximatelyconstant after fertigation in theworks of Jiang et al. (2012) and Silvaet al. (2014), however, in both cases the soils presented more acidiccharacteristics, with pH ranges respectively of 4.89e4.93 and5.38e5.60 after 1e3 years of continuous application. Actually inJiang et al. (2012) fertigation have increased the soil pH, since theinitial values ranged from 4.36 to 4.56. Such behavior may berelated to both the introduction of basic ions (e.g. Ca2þ and Mg2þ)commonly found in stillage and the consumption of Hþ ions inredox reactions conducted by microorganisms (Brito et al., 2009;Sivaloganathan et al., 2013). The prompt input of organic matterin soil tends to enhance the oxygen consumption and create regionsof anaerobiosis, leading to a decrease in the redox potential of thesoil (Brito et al., 2009). The aerobic oxidation of organic matter alsoenhances the consumption of acidity, since the oxidation of organiccarbon releases electrons potentially captured by Hþ ions. Furtherdescriptions regarding the fate of organic matter in soils are pre-sented in Section 3.2.

Jiang et al. (2012) have also detected reductions in the bulkdensity and porosity of the soil amended with stillage, as a directconsequence of the predominance of large water-resistant soilaggregates (>1 mm). Soil bulk density and porosity indicate thestatus of soil compactation, so that large aggregates improve soilaeration, as well as regulate the water retention and the release ofnutrients and organic matter to the crops (Jiang et al., 2012).Similar results have been reported by Previna and Saravanan(2013), in which the application of anaerobically treated stillageinto sugarcane fields has increased the microbial activity and theenzymatic activity in the soil. Improvements in the activity ofmicrobial populations are important for organic matter andnutrient transformation within the soil layers, making themavailable to crops. Direct results from such scenarios tend toinclude higher crop productivities, as observed by Tasso et al.(2007) and Sivaloganathan et al. (2013). Sivaloganathan et al.(2013) have associated higher sugarcane (115 ton ha�1) andsugar (13.50 ton ha�1) yields to the application of diluted treatedstillage in a proportion of 1:10 e the values for the sugarcane andsugar in the control plot were respectively 78 and 9.02 ton ha�1.Tasso et al. (2007) the application of raw stillage into sugarcanefields have improved the concentrations of total reducing sugars inthe sugarcane, in comparison with the use of mineral fertilization(142.7 vs. 140.55 kg ton�1). According to Zolim et al. (2011), thegreater readily-available potassium content supplied in stillageenhances sugarcane productivity and the synthesis and accumu-lation of sucrose in stalks.

In fact, the above described benefits may increase the cropproductivity in the short term. However, considering successiveapplications of stillage, especially when adequate criteria fordefining dosages and planning of the irrigation systems are notconsidered, a deterioration in the physicochemical characteristics(i.e. agricultural potential) of the soil will be observed, also result-ing in impacts on superficial water bodies and groundwater.Although such a scenario can be expected, there is a lack of data inthe literature regarding the monitoring of the environmentalquality in areas continuously fertigated with stillage. Thus, some of

the impacts discussed in this review are considered as ‘potentialimpacts’.

3. Polluting and contaminant potential of stillage

Considering the compositional characteristics of stillage, themain adverse effects associated with its reuse in agriculture resultfrom the excessive input of organic matter and nutrients to the soil.Furthermore, high concentrations of salts, such as sulfates, chlo-rides and nitrates, are found in stillage, so that impacts due to theirbuild-up should also be highlighted. Table 1 summarizes data fromstudies on the adverse environmental impacts of stillage on the soilproperties and water bodies. Although the adverse effects varyaccording to the type of fertigated soils, the following impacts canbe expected from the continuous application of stillage to theagricultural fields (Wilkie et al., 2000; Ramana et al., 2002; Tejadaand Gonzalez, 2006; Gunkel et al., 2007; Pant and Adholeya, 2007;Satyawali and Balakrishnan, 2008; Mariano et al., 2009; Mohanaet al., 2009; Espa~na-Gamboa et al., 2011):

1. Soil salinization and sodification, leading to salt leaching togroundwater and increasing soil instability;

2. Organic overload, in order to clog soil pores up and promotereductions on the concentrations of dissolved oxygen (DO) andmicrobial activity, as well as stimulate the generation of un-pleasant odors due to the putrefaction (i.e. anaerobic con-sumption) of readily available organic carbons;

3. Soil overfertilization, which can cause side effects, such as thedestabilization of the soil structure, as well as the eutrophica-tion of water bodies supplied by nutrient-rich runoffs;

4. Contamination by specific ions (e.g. nitrate and chloride) andtoxic metals (e.g. priority pollutants, such as lead, copper andzinc);

5. Permanent soil and water resources acidification, based on thecontinuous supply of Hþ ions and losses on the soil alkalinity;

6. Interference in the process of photosynthesis carried out byaquatic plants, since the high color and turbidity of stillage maygenerate a barrier to sunlight penetration in water bodies; and,

7. Inhibition of seed germination, reduction in crop yields andgeneration of toxicity in aquatic environments.

Although there are several international regulations relating toacceptable concentrations of substances, such as toxic metals, inirrigationwaters, we used the limits (reference values) described bytheWorld Health Organization (WHO, 2006) as themain referencesdue to its general character and broad applicability. Furthermore,the use of specific legislation from Brazil and USA as references,especially when considering the presence of toxic metals, is due tothe importance of both countries' ethanol industries in the globalcontext, since they are the two biggest ethanol producers globally.The Brazilian ethanol production from sugarcane reached about 24billion liters in 2013 (CONAB, 2013), which corresponds toapproximately 64% of the ethanol production from corn in the USAat the same period e 37.5 billion liters (EIA, 2013).

3.1. Soil salinization: impacts associated with the build-up of salts

In general, salinization comprises the main adverse effect fromthe application of wastewaters to agricultural fields, so that severalimpacts may be observed: [i] reduction on the soil's osmotic po-tential, in order to unbalance the absorption of water and nutrientsby the plants; [ii] generation of toxicity due to the presence ofspecific ions; and [iii] destruction of the soil structure by dispersingsoil particles and clogging up pores (USEPA, 2004; Tejada andGonzalez, 2006; WHO, 2006). These impacts might be adequately

Table 1Impacts on the soil structure and water resources from stillage land application.

Reference Stillage characterization Soil and/or cropcharacterization

Applicationrate

Observed effects

Jain et al. (2005) Anaerobically treated sugarcanemolasses stillage: COD ¼ 31 g L�1;BOD ¼ 4.8 g L�1; TDS ¼ 5440 mg L�1;EC ¼ 8.5 dS m�1; Ntotal ¼ 2100 mg L�1;[Na] ¼ 535 mg L�1; [Cl�] ¼ 2116 mg L�1

Sandy loam soil(~65% sand, 20% silt,15% clay): bulkdensity ¼ 1.45 g cm�3;EC ¼ 0.3 dS m�1;SAR z 4.5; Ntotal ¼ 0.05%

Average ratea:225 m3 ha�1

Increase in groundwater ECb: 0.83e1.04 dS m�1

Increase in groundwaterTDS concentrations:

314.4e998.4 mg L�1

Increase in groundwaterNO3

� concentrations:16.95e59.81 mg L�1

Riceewheat was thedominant croppingsystem of the area

Increase in groundwaterNa concentrations:

36.8e68.8 mg L�1

Increase in SAR: 0.6e4.0Increase in groundwaterCl� concentrations:

12.9e43 mg L�1

Kaushik et al. (2005) Anaerobically treated sugarcanemolasses stillage: COD ¼ 30.15 g L�1;BOD ¼ 8.45 g L�1; TDS ¼ 5440 mg L�1;EC ¼ 8.5 dS m�1; pH ¼ 7.5

Sodic soil: EC ¼ 1.0dS m�1; ESP ¼ 26%;pH ¼ 9.1

e Increase in groundwater ECb: 1.1e4.0 dS m�1

Decrease in soil microbialbiomass (bacteria count):

57 � 105e29.4 � 105

Pearl millet (forage crop)germination inhibition:

Seed germination of only 15e35%

Tejada andGonzalez (2006)

Beet molasses stillage: organicmatter ¼ 398 g kg�1; [Na] ¼ 26.2 g L�1;pH ¼ 4.9

Typic Xerofluvent(68.9% sand, 13.1%silt, 18% clay) underdryland conditions:bulk density ¼ 1.38 g cm�3;EC ¼ 0.24 dS m�1; instabilityindex ¼ 1.48; exchangeablesodium percentage(ESP) ¼ 2.3%;SMB ¼ 146 mgC g�1 dry soil

25.12 ton ha�1c Increase in soil bulk densityd: 1.50e1.71 g cm3

Increase in the soil structural instabilitye: 1.41e1.73Decrease in SMB: 127e48 mgC g�1 dry soilIncrease in ESPf: 7.6e15.1%

All the plots were coppedwith wheat

Increase in cumulative soil loss (simulatedrain of 45 min, intensity of 140 mm h�1):

651 to 842 kg ha�1

Gunkel et al. (2007) Fertigation fluid (sugarcane juicestillage diluted at a ratio of 6:4 withirrigation water or sugarcane washwater): COD ¼ 23.7 g L�1;BOD ¼ 10.8 g L�1; EC ¼ 7.6 dS m�1;pH ¼ 3.8; Turbidity > 1000 NTU;Temperature ¼ 36.8 �C

Sugarcane field locatednearby Ipojuca River, acoastal river in the state ofPernambuco in NortheastBrazil.

e Reduction in surface water DO concentrations: 5.5e2.8 mg L�1

Increase in river temperature in 2e3 �C 29 to 31e32 �CWater slightly acidification: pH decrease from 6.7 to 6.0Increase in the organic matter content ofthe surface water:

BOD: <2e20.8 mg L�1

COD: <15e49.5 mg L�1

Increase in river turbidity: 40 to 60-100 NTU

Hati et al. (2007) Sugarcane molasses stillage:COD ¼ 113.2 g L�1; BOD ¼ 36 g L�1;EC ¼ 25.3 dS m�1; pH ¼ 4.2

Typic Haplustert (heavyclay soil): bulkdensity ¼ 1.3 g cm3; pH ¼ 7.9

250 m3 ha�1 Increase in groundwater ECb 0.47 to 1.52 dS m�1

Soybean-wheat crop systemMariano

et al. (2009) gSugarcane juice stillage:COD ¼ 32 g L�1; EC ¼ 8.52 dS m�1;pH ¼ 3.85

Soil samples from two petrolstations (P1 and P2) whereoil spills occurred fromunderground tanks

33 g kg�1soil Increase in groundwater ECb P1: 0.44 to 1.02 dS m�1

P2: 0.25 to 0.87 dS m�1

Increase in the organic matter content (COD)of groundwater (evidence of organic overload)

P1: 41.5e1699 mg L�1

P2: 37.8e1888 mg L�1

Reduction in groundwater DO concentrations P1: 7.9 to 0.5 mg L�1

P2: 8.3 to 0.8 mg L�1

Increase in groundwater nitrate (NO3)concentrationsh

P1: 3.52e52.8 mg L�1

P2: 3.52e39.6 mg L�1

Increase in the groundwater Kþ concentrations P1: 16.1e372 mg L�1

P2: 4.49e361 mg L�1

Rolim et al. (2013) Sugarcane juice stillage:COD ¼ 21.5 g L�1; BOD ¼ 12 g L�1;TDS ¼ 7690 mg L�1; EC ¼ 13.75 dS m�1;

Influence area of astillage-distributionlagoon, located at a

e Increase in groundwater organic matter content: COD: 325.5 mg L�1

BOD: 36.7 mg L�1

Increase in groundwater TDS concentrations: 745.7 mg L�1

L.T.Fuess,M.L.G

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L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 215

prevented by analyzing the wastewater in terms of its electricalconductivity (EC) and/or total dissolved solids (TDS) content, suchthat significant problems tend to occur when EC > 3.0 dS m�1 andTDS > 500 mg L�1 (WHO, 2006). Jain et al. (2005), Kaushik et al.(2005) and Mariano et al. (2009) have reported an EC of8.5 dS m�1 for stillage samples from sugarcane, while Hati et al.(2007) and Nandy et al. (2002) have indicate values as high as25.3 and 53.8 dS m�1. Considering the TDS content, concentrationsas high as 150 g L�1 may be observed in stillages from molasses(Mohana et al., 2009), indicating the unsuitability of applying stil-lage directly into the soil, as in the long term fertigation withwastewaters will always increase salinity of the soils (WHO, 2006).Jain et al. (2005), Hati et al. (2007) and Mariano et al. (2009) havereported increases in the groundwater EC to values ranging from0.87 to 1.52 dS m�1 after the application of stillage (Table 1). InKaushik et al. (2005) the observed value of EC has reached4.0 dSm�1. Since stillage is mostly applied to sugarcane fields, someconsiderations should be made about the effects of salinity onsugarcane growth and yield. Studies indicate that sugarcane toler-ates root zone salinities less than 2.0e2.5 dS m�1 (Wiegand et al.,1996; Wahid et al., 1997; Ayers and Westcot, 1999), so that noadverse effects are observed on its growth and yield. However, foreach 1 dS m�1 increase in groundwater EC reductions on stalkpopulation, stalk weight and stalk yield are expected (Wiegandet al., 1996). Such productivity loss also affects the quality of thesugarcane, in order to reduce the content of total soluble solids andsucrose in juice by approximately 0.5% per dS m�1(Lingle andWiegand, 1997). When EC reaches values greater than8.0e10.0 dS m�1, reductions of at least 50% should be observed onsugarcane yield (Wiegand et al., 1996; Wahid et al., 1997; Santanaet al., 2007). Regarding the effect of stillage over other crops,Ramana et al. (2002) have assessed the effects of different sugar-cane molasses stillage concentrations (0, 5, 10, 15, 20, 25, 50, 75 and100%, v/v) on seed germination of some vegetable crops (i.e. cu-cumber, tomato, chilli, bottle gourd and onion. Although the au-thors have observed that the effects of stillage are crop-specific,significant reductions on seed germination of tomato wereobserved for stillage concentrations above 5%. With respect to theother crops, critical concentration values of stillage comprised 25%.Besides, regardless the crop, for stillage concentrations of 75 and100% complete failure of germination was observed. In short, theauthors have attributed such inhibitory effects to the high con-centrations of salt in stillage, which has changed the osmotic po-tential in the cultivation medium and consequently has limited thewater uptake by the seeds. Similar effects have been reported byKannan and Upreti (2008), in which toxic effects of raw molassesstillage on seed germination and plant growth of mug bean havebeen observed for stillage concentrations as low as 5% (v/v). In thiscase, the authors have observed significant leaching of carbohy-drates and proteins from the seeds due to limitations in wateruptake, leading to high enzymatic activity losses. Besides the in-fluence of high salinity, the toxic effects described by Kannan andUpreti (2008) have also been related to factors such as soilorganic overload and inhibition by heavy metals.

A direct consequence from salinization in fertigated areas is thesalt leaching, which may be detected by measuring the character-istics of the groundwater. Based on a study conducted in a nearbyarea to a stillage storage tank, Cruz et al. (2008) have appliedgeophysical methods to analyze the changes in the groundwaterdue to the presence of stillage, so that a reduction of about 95%(1800e~90 Ohm m�1) was identified in the soil resistivity. Thepattern observed was the same usually found in areas contami-nated by landfill leachate, which also present a high salinity (Mouraand Malagutti Filho, 2007; Moreira and Braga, 2009; Lopes et al.,2012). Lyra et al. (2003) have not observed significant changes in

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229216

groundwater, in terms of COD, BOD and EC, in an area continuouslyfertigated with stillage located at Ipojuca, Brazil. Such resultsprobably indicate the build-up of salts in the soil below the satu-ration levels, i.e., due to the retention of salts in the soil structure noleaching has been observed, so that the groundwater quality hasnot been changed. Similar results have been reported in Silva et al.(2014), in which groundwater EC values have reached maximumvalues around 0.37 dS m�1 after stillage application in a floodplainarea cultivated with sugarcane e EC values in control areas (i.e.without stillage) were 0.2 dS m�1. In this case, although the studyhas been conducted only during 9 months, two important factorsshould also be considered, since lower stillage application rateshave been used (50e65m3 ha�1 per year, corresponding to 30e43%of the common valuese 140e150m3 ha�1, BNDES and CGEE, 2008),as well as precipitation has diluted the fertigation fluid.

Although it is widely known that stillage is characterized by ahigh salt content, the works usually report only concentrationvalues for sulfate, especially when considering sugar-based feed-stocks. Considering adverse effects on sugarcane, Joshi and Naik(1980) have studied the toxicity of different ions on the crop, inorder to establish a decreasing degree of toxicity as follows:SO4

2� > Naþ > Cl� > Mg2þ. In short, sulfate salts have inhibitedsugarcane growth and chlorophyll synthesis, as well as decreasedthe uptake of potassium and calcium. Table 2 depicts a compilationof specific salts found in stillages from different feedstocks.Regarding sulfate, concentrations higher than 5000 mg L�1 arenormally found in molasses stillages (Driessen et al., 1994; Acharyaet al., 2008; Kumar et al., 2007; Kaushik et al., 2010; Silva et al.,2014), which may also contribute to the generation of unpleasantodors in the occurrence of anaerobisis, due to the generation ofsulfides via sulfate-reduction. Excessive chloride concentrationshave also been found in molasses stillages, with values of up to8000e8500 mg L�1 (Goyal et al., 1996; Nandy et al., 2002; Acharyaet al., 2008; Kaushik et al., 2010). Jain et al. (2005) have detected

Table 2Specific salts found in stillages from different feedstocks.

Ethanol feedstock Reference Salt level (mg L�1)

Sulfate (SO42�) Pho

Sugarcane (juiceor juice þ molasses)

Driessen et al. (1994) 400 58Ribas (2006) 1645e1920 e

Fuess (2013) 2300e7000 e

Rolim et al. (2013) e e

Santos et al. (2013) 1680 560

Sugarcane molasses Bories et al. (1988) 3820 e

Driessen et al. (1994) 3000e16,000 140Goyal et al. (1996) 2000e5000 500Pathak et al. (1999) 1500 e

Shivayogimath andRamanujam (1999)

2000e3200 300

Nandy et al. (2002) 2100e2300 300Ramana et al. (2002) 1310 e

Jain et al. (2005) a 4270 e

Banu et al. (2006) 1800e3000 250Acharya et al. (2008) 7500e9000 250Hati et al. (2007) 1310 e

Kumar et al. (2007) 6000e6500 e

Kannan and Upreti (2008) 1200 20Chandra et al. (2009) 3786 680Kaushik et al. (2010) 4000e6000 364Silva et al. (2014) 18,894 e

Beet molasses Boopathy and Tilche (1991) 1042 175Jim�enez et al. (2003) 5000 e

Corn Andalib et al. (2012) e 110

e ¼ Data not available.a Data refer to post-methanated stillage.

chloride concentrations of about 2100 mg L�1 (Table 2) in post-methanated sugarcane molasses stillage, so that its soil applica-tion has significantly increased the concentrations of Cl� ions ingroundwater (12.9e43 mg L�1, Table 1). In Rolim et al. (2013) theconcentration of chlorides in groundwater has reached an averagevalue of 745 mg L�1 (Table 1) in the influence-area of a stillage-distribution lagoon, located at a sugarcane field (sandy soil). Suchvalue exceeds about three times the maximum permissible valuefor chlorides in waters for human supply in Brazil, consideringgroundwater uptake (Brasil, 2008). As chloride is not entrapped oradsorbed by soil particles, it may be easily absorbed by the rootsalong with the (waste)water supplied, so that the ions reach theleaves by translocation. Severe damages result from excessiveconcentrations of chloride in the foliar tissue, including reducedgrowth, burnt foliage, defoliation and even necrosis (Furlani et al.,1976; Cruz et al., 2006), leading to significant productivity losses.The recommended limits for chloride in wastewaters for irrigationare similar to the ones established for free chlorine, reaching con-centrations below 1 mg L�1 (USEPA, 2004), however, severe shouldbe verified in sensitive plants at concentrations as low as0.05 mg L�1, majoring deficiencies on the uptake of essential nu-trients, such as potassium and sulfur (Cruz et al., 2006), and re-ductions on plants dry weight (i.e. biomass losses) (Watkins andHammerschlag, 1984). Toxic effects of chloride should also beobserved on the soil microbial biomass, in order to inhibit the ac-tivity of fungal populations (Ke et al., 2013) and nitrifying bacteria(Megda et al., 2014) surrounding plant rhizosphere. Such impactscompromise the soil health, reducing its capacity in cycling organicmatter and nutrients to plants.

Special attention should also be directed to the presence of so-dium in stillage due to the occurrence of soil sodification (Fig. 2), inwhich Naþ ions act as dispersive agents by disrupting soil aggre-gates, in order to clog soil pores up and reduce water infiltration(Richards, 1954; Tejada and Gonzalez, 2006; Tejada et al., 2007).

Electricalconductivity (dS m�1)

sphate (PO43�) Chloride (Cl�) Nitrate (NO3

�)

e e e

e e 7.4e13.5e 45e75 6.7e8.71219 e 13.7559.4 e e

2840 e e

0 e 3650 e

e1500 5000e8000 e e

e e 15e800 e e e

e400 5800e7600 40e50 51e53.84050 Trace 25.32116 e 8.5

e750 e e e

0e2700 8000e8500 e e

e e 25.35500e6000 e e

1300 e e

1860 e 10.765000e8000 6071 8.5e e e

1191 e e

e e 40

0 e 16 e

Fig. 2. Influence of sodium on the soil's aggregation state: a. highly dispersed soil due to high Naþ concentrations, b. highly cohesive soil due to high concentrations of Ca2þ andMg2þ (filled circles represent both Ca2þ and Mg2þ ions; unfilled bars represent clay particles). Reference: modified from Lepsch (2011).

Table 3Sodium adsorption ratio (SAR) for stillages from different feedstock.

Reference Ethanol feedstock Na Ca Mg Ratio Na:Ca SAR

mg L�1 mg L�1 mg L�1

Sheehan and Greenfield (1980) Sugarcane 1040 3520 1630 0.3:1 3.63Bories et al. (1988) Sugarcane 150 1460 870 0.1:1 0.77Karhadkar et al. (1990) Sugarcane 2700 2200 e 1.2:1 e

Harada et al. (1996) Sugarcane 32 600 e 0.05:1 e

Shivayogimath and Ramanujam (1999) Sugarcane 150 2600 1600 0.06:1 0.57Lyra et al. (2003) Sugarcane 325 600 310 0.5:1 2.68Banu et al. (2006) Sugarcane 220 2500 e 0.1:1 e

Tejada and Gonzalez (2006) Beet 26,250 48.75 18.75 470:1 809.60Brito et al. (2007) Sugarcane 113 352 12 0.3:1 1.6Bianchi (2008) Sugarcane 1.6 1393 650.5 0.001:1 0.01Mariano et al. (2009) Sugarcane 113 740 210. 0.15:1 0.94Alkan-Ozkaynak and Karthikeyan (2011) Corn 402.6 27.3 586.4 15:1 3.51Ferreira et al. (2011) Sugarcane <50 460 290 0.1:1 0.45Wilkinson (2011) Corn 276 36 674 8:1 2.24Fuess (2013) Sugarcane 53.28 570 165.2 0.1:1 0.51Rolim et al. (2013) Sugarcane 300 560 280 0.5:1 2.58Silva et al. (2014) Sugarcane 759 57.9 423.45 13.1:1 7.6

e ¼ Data not available.

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 217

The occurrence of sodification may be predicted by using [i] theratio sodiumecalcium (Na:Ca) and [ii] the sodium adsorption rate(SAR), which relates the concentrations of Na, Ca and Mg in theirrigationwater. Table 3 presents the risks of sodification associatedwith stillages from different feedstocks, so that significant impactsmight be expected when Na:Ca > 3:1 and SAR > 10 (Richards, 1954;USEPA, 2004; WHO, 2006). Sugarcane stillages tend to presentNa:Ca ratios (0.001:1 to 1.2:1, Table 3) significantly lower than thereference value. Apparently the adverse effects from sodificationare more likely to occur in soils fertigated with more concentratedstillages, especially the ones from beet and corn, based in Na:Caratios as high as 470:1 (beet, Tejada and Gonzalez, 2006, Table 3)and 15:1 (corn, Alkan-Ozkaynak and Karthikeyan, 2011, Table 3).Tejada and Gonzalez (2006) and Tejada et al. (2007) have reportedreductions on soil stability (~25%) and microbial activity (~45%), aswell as an increase in bulk density (~23%), after applying fresh beetmolasses stillage (25 ton yr�1) to a sandy arid soil (Table 1). In suchcases, local anaerobiosis is generated by the clogging up of pores, aspoor aeration zones are created. Since anaerobic microorganismshave lower growth rates than the aerobic ones, decreasedmicrobialand enzymatic activities are predominant, enhancing soil insta-bility, as metabolites excreted by the aerobic biomass during themineralization of organic compounds help to improve the inter-particular cohesion (Kaushik et al., 2005; Tejada and Gonzalez,2006; Robles-Gonz�alez et al., 2012).

Yet regarding the study of Tejada and Gonzalez (2006), a sig-nificant increase in the soil exchangeable sodium percentage (ESP)has been detected (7.6e15.1%). According to Richards (1954) andBernstein (1975), for ESP values greater than 15% of the cation-

exchange capacity sodicity reaches critical levels, in order toenhance the impacts previously described. Jain et al. (2005) havealso observed significant increases in both groundwater sodiumconcentrations (36.2e68.8 mg L�1) and sodium adsorption rate(0.6e4.8) in areas amended with anaerobically treated molassesstillage. Differently, in Pathak et al. (1999) and Silva et al. (2014) theapplication of post methanated and raw molasses stillage, respec-tively, has not generated adverse conditions related to the excessiveconcentration of sodium in groundwater and soil. In fact, Pathaket al. (1999) have related increases on the soil water content andbulk density after fertigation. However, despite the absence ofimpacts on the soil physical structure, the excessive uptake of so-dium may also cause burnt foliage and foliar tissue necrosis,reducing the crop productivity (Furlani et al., 1976). In sensitiveplants (e.g. corn) such impacts are observed for ESP <15%, while insemi-tolerant plants (e.g. sugarcane and sweet sorghum) severedamage should occur for ESP >40% (Ayers and Westcot, 1999).

3.2. Influence of organic matter on soil components: impacts on theconcentrations of dissolved oxygen and microbial activity

The controlled application of organic matter to soil providesseveral benefits, as previously pointed out in Section 2. In short, theorganic matter input increases the concentration of negative-charged particles in the soil, which improves the retention of wa-ter and nutrients, as well as stimulates the microbial activity andconsequently the cementation of the soil aggregates due to theflocculation of the particles (Tejada et al., 2007; Cruz et al., 2008;Gariglio, 2008). Hati et al. (2007) have detected a reduction in the

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229218

soil bulk density (from 1.3 to 1.0 g cm�3) as a direct result fromincreasing its organic content after applying different volumes ofstillage into a soybean-wheat system. Furthermore, the authorshave estimated an increase of about 176% in the microbial activity,in addition to higher seed yields for both soybean (up to2.09 Mg ha�1) and wheat (up to 3.46 Mg ha�1). Miranda et al.(2012) have also reported reductions on soil bulk density(1.60e1.41 g cm�3) after applying raw sugarcane stillage to a sandysoil, as well as increases in soil porosity (40e47%) and moisture(7e12%). Biswas et al. (2009) have observed that the application ofboth raw and post-methanated molasses stillage to a Vertisoil(soybean-wheat system) have increased soil aggregates stabilitythrough enhanced organic carbon, as well as the aggregate-associated carbon. In this case, no significant differences havebeen observed in soybean yields, considering both mineral fertil-ization and fertigation, while wheat yields varied according to theapplied dosages of stillage. In Pathak et al. (1999) the rise in the soilwater content ranged from 38.8 to 44.3% (v/v) after the disposal ofstillage in dosages of up 240 m3 ha�1. In this study higher seedyields have also been observed for wheat and rice, however, stillagewas anaerobically treated and diluted prior to its application, inorder to reduce its organic load.

Indeed, such positive impacts are commonly associated with thedisposal of domestic sewage, whose organic matter (in terms ofBOD) and TDS content are lower than 400 and 900 mg L�1,respectively (von Sperling, 2007). Pathak et al. (1999) haveobserved that stillage could be suitable for fertigation by diluting itto BOD values below 1000 mg L�1. In Sivaloganathan et al. (2013)the higher sugarcane yields have also been related to the applica-tion of previously treated and diluted stillages, considering ratios ofup to 1:50. The lower BOD values in raw stillages are~10,000 mg L�1 (Costa et al., 1986; Driessen et al., 1994; Ferreiraet al., 2011) for the streams resulting from sugarcane juice. Theminimum TDS concentrations in stillage also correspond to~10,000 mg L�1 (Lyra et al., 2003; Fuess, 2013), so that anotherbarrier to its direct land application should be highlighted. In termsof equivalent population, a relatively large-scaled distillery, pro-ducing ~1000 m3 of ethanol (Dias et al., 2011) from sugarcanemolasses daily, generates an average organic load of 585 Mg d�1 asBOD, which is similar to the polluting potential of a 12-million-people population (Fig. 3). Such numbers are equivalent to citieslike S~ao Paulo and Delhi.

Similarly to the conditions observedwhen soil pores are cloggedup, the excessive input of biodegradable organic matter to soils also

Fig. 3. Equivalent populationa with the same polluting potential from sugarcane-baseddistilleries (whole lines refer to molasses stillage; dashed lines refer to juice and juicestillage). aCriteria for the estimates: per capita BOD contribution ¼ 50 g day�1 (vonSperling, 2007); stillage generation rate ¼ 13 L L�1 EtOH (BNDES and CGEE, 2008);BOD ¼ 20 g L�1 (juice) (Russo et al., 1985) and 45 g L�1 (molasses) (Kumar et al., 2007).

tends to enhance the occurrence of anaerobic conditions, however,in this case due to the intense oxygen consumption by the aerobicmicrobial community initially present on the soil and groundwater(Tejada and Gonzalez, 2006; Tejada et al., 2007; Renault et al., 2009;Robles-Gonz�alez et al., 2012). Mariano et al. (2009) have reportedreductions on the groundwater dissolved oxygen concentrationsgreater than 90% (7.9e8.3 to 0.5e0.8 mg L�1, Table 1) in a studybased on the use of sugarcane stillage as a source of nutrients in soilbioremediation. The authors have also indicated an expressive in-crease in groundwater COD values (37.8e41.5 to 1699e1888mg L�1,Table 1) after the application of stillage, as a direct consequencefrom the organic overload. The groundwater BOD and COD valuesobserved by Rolim et al. (2013) have also reached critical values(respectively 36.7 and 325.5 mg L�1, Table 1) after continuousstillage storage in a lagoon located at a sugarcane field. Oxygendepletion also comprises the main adverse effect from the directdischarge of stillage into water bodies. Gunkel et al. (2007) havealso conducted a critical assessment on the impacts of the contin-uous land disposal of stillage in a nearby sugarcane field to theIpojuca River, Pernambuco, Brazil, in order to report reductions ofup 50% in the dissolved oxygen of the superficial water(5.5e2.8 mg L�1, Table 1). Although in this case stillage was notdirectly discharged into the water, it could reach the river by therunoff in drainage canals from the sugarcane field. Regarding thepresence of organic matter, the authors have also observed signif-icant rises on BOD (<2e20.8 mg L�1) and COD (<2e49.5 mg L�1)values (Table 1). According to the Brazilian environmental legisla-tion, superficial water bodies in which DO and BOD concentrationsare below 4 mg L�1 and above 10 mg L�1, respectively, should beused only for navigation and ‘landscape harmony’ (Brasil, 2005), sothat practices like human supply, irrigation of tree crops, and sec-ondary contact should be avoided.

Additionally, a deterioration in the groundwater quality may beobserved, as the build-up of organic compounds should lead toaesthetic problems, such as color, turbidity odor and taste(Satyawali and Balakrishnan, 2008; Mohana et al., 2009; Espa~na-Gamboa et al., 2011). Regarding the influence of color, mostworks usually describe stillage only as a ‘dark brown’ effluent,based on visual analyses (Kaushik et al., 2005; Satyawali andBalakrishnan, 2008; Mohana et al., 2009; Christofoletti et al.,2013), without considering quantitative aspects. Exceptions maybe found in Nandy et al. (2002), Pandey et al. (2003) and Fuess(2013), who have indicated color levels ranging from 17,000 to60,000 mg Pt L�1 for sugarcane stillages, and Rodrigues et al.(2013), who have reported color levels of 6800e23,600 mg Pt L�1

for anaerobically treated sugarcane stillage. The literature also lacksdata regarding the quantitative characterization of turbidity instillages, which may vary from 2000 to 30,000 NTU in raw (deBazúa et al., 1991; Zayas et al., 2007; Fuess, 2013) and 180 to4600 NTU (Zayas et al., 2007; Rodrigues et al., 2013) in post-methanated effluents. Gunkel et al. (2007) have measuredturbidity concentrations above 1000 NTU (Table 1) in the fertiga-tion fluid (i.e sugarcane juice stillage diluted at a ratio of 6:4 withirrigationwater or sugarcanewashwater) directed to the sugarcanefields. The direct contact of such fluid with water (through therunoff) has increased turbidity in Ipojuca River up to 100 NTU,indicating at least the need for conventional water treatment (e.g.coagulationeflocculation, sedimentation and filtration) previouslyto human consumption (Brasil, 2005).

3.3. Soil overfertilization: build-up of macronutrients (N, P and K)

The nutrient content found in stillage may usually supply mostof the plants requirements, despite its great compositional vari-ability (Fig. 1). However, the excessive nutrient input to the

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 219

agricultural fields also tends to cause several adverse impacts onthe soil structure, as well as to the crop productivity and waterresources (Tejada and Gonzalez, 2006; Arienzo et al., 2009; Pantand Adholeya, 2007). Regarding nitrogen, although severalstudies highlight some benefits to the crops, such as higher pro-ductivities, from the application of wastewaters and sludge (e.g.domestic sewage) containing nitrogen concentrations (as Ntotal) inthe range of 20e85 mg L�1 (Asadi et al., 2002; Tasso et al., 2007), itsexcess may be associated with important negative effects, whichalso affect the crop productivity. The excess uptake of nitrogen canstimulate the plant growth at levels above the desired, leading tolosses in quality and quantity of the crop by increasing the plantsucculence, i.e. the water storage in the plant tissues (Cruz et al.,2000). The main consequences from this scenario include theoccurrence of lodging in grain crops (Podg�orska-Lesiak andSobkowicz, 2013; Zhang et al., 2014) and drastic reductions in thesugar content, as well as in the overall rate of biomass accumula-tion, in sugar-based feedstocks, such as sorghum and sugarcane(USEPA, 2004; Berding and Hurney, 2005; Park et al., 2005; WHO,2006), so that such impacts may affect directly the production ofsugar and ethanol.

Although nitrogen may be classified as the “most essential”nutrient to plants, its suitability as a fertilizer depends on thepredominant chemical forms present in the wastewaters reused.While most plants absorb nitrogen as nitrate (NO3

�), approximately85e90% of the Ntotal in stillage correspond to organic nitrogen(Sheehan and Greenfield, 1980; Fuess, 2013), due to the presence ofresidual proteins remaining from the feedstock preparation. Thiscompositional characteristic explains the low fertilizing potential ofstillage in terms of its nitrogen content, which is not readilyassimilable by the plants. Additionally, the excess of organic ni-trogen may enhance the nitrifying activity in the soil, also leadingto reductions in the oxygen concentrations and to eventual gen-eration of nitrous oxide (N2O) (Espa~na-Gamboa et al., 2011),depending on some specific factors, such as soil moisture and pHand the availability of biodegradable organic matter. Most of N2Orelease tends to occur right after the application of stillage, sincethe local anaerobic conditions stimulates denitrifying microor-ganisms. Studies have indicated that emissions of N2O in areasfertigated with stillage tend to be low, accounting for only 1%(7.5e51.9 kgN2O ha�1 yr�1) of the total emissions of greenhousegases in irrigation canals (Carmo et al., 2013; Oliveira et al., 2013).However, since the global warming factor of N2O is about 300 timesgreater than the one observed for carbon dioxide, its effects shouldbe critically considered in the Brazilian ethanol industry, based onthe large areas used in the cultivation of sugarcane.

Yet concerning the effects of nitrogen, significant concentrationsof ammonia have been identified in stillages from different feed-stocks, ranging from 100 to 550 mg L�1 (Braun and Huss, 1982;Shrihari and Tare, 1989; de Bazúa et al., 1991; Nandy et al., 2002;Andalib et al., 2012). Besides contributing to the nitrifying activityenhancement, ammonia is extremely toxic to aquatic organisms,since fish and amphibians lack specific mechanisms to prevent itsbuild-up in the bloodstream. The lethal dose of ammonia for mosttropical fishes may be lower than 1e3 mg L�1, based on acuteexposure (Piedras et al., 2006). High concentrations of nitrates mayalso be found in fertigated areas, considering both the presence ofsuch ions in raw stillage and their generation through the aerobicoxidation of Norg/NH3 to NO3

�. Since nitrates are highly soluble inwater, significant losses are observed during fertigation, in order topromote its build-up in the groundwater and surrounding waterbodies. Mariano et al. (2009) have reported increases in thegroundwater NO3

� concentrations exceeding 1000% the naturalcontent of such ion, leading to concentrations as high as52.8 mg L�1 (Table 1). Similar results have been indicated by Jain

et al. (2005), where the NO3� concentrations measured varied

from 16.95 mg L�1, in non-fertigated areas, to 59.81 mg L�1, infertigated fields (Table 1). Such nitrate concentrations have reachedlevels above the limit (10 mg L�1) determined by the Brazilian andUS environmental legislation on drinkable waters for public use(Asadi et al., 2002; Brasil, 2011b). Considering the fate of nitrate ingroundwater, potential impacts could be observed on populationseventually supplied by contaminatedwater resources, as the nitratebuild-up in mammals is related to the occurrence of methemo-globinemia. In short, such disease is characterized by the massiveoxidation of the iron (Fe2þ / Fe3þ) in the hemoglobin molecules,so that the oxygen transportation in the tissues is compromised(Batalha and Parlatore, 1993; Asadi et al., 2002).

Considering the excess of phosphorus, the main adverse effectsare associated with its build-up in water bodies, leading to theoccurrence of eutrophication through a sequence of events: pro-liferation of aquatic plants; enhancement of the aerobic biodegra-dation of dead plant tissues, leading to anaerobic conditions andsignificant biodiversity losses (Asadi et al., 2002; von Sperling,2007; WHO, 2006). Additional impacts from eutrophicationinclude the: [i] interference in aesthetic, recreational and transportcharacteristics of the water body due to the proliferation of algaeand aquatic macrophytes; [ii] increasing costs of water treatment;and, [iii] release of odors from the anaerobic decomposition ofsulfur-compounds (Arthington et al., 1997; von Sperling, 2007;Hartemink, 2008). Although several authors consider eutrophica-tion as a potential adverse effect from fertigationwith stillage (Pantand Adholeya, 2007; Satyawali and Balakrishnan, 2008; Mohanaet al., 2009; Espa~na-Gamboa et al., 2011), the literature lacks thedescription of its occurrence in areas nearby fertigated fields,considering the proliferation of aquatic plants and other correlatedimpacts. However, in such cases effects similar to those observed insewage-polluted water bodies should occur (e.g. high concentra-tions of nutrients inwater, mainly P and N; high microbial and algalactivities; high water turbidity; and accumulation of sediments e

Huang et al., 2003; Withers et al., 2011), since stillage has nutrientconcentrations much higher than sewage. Considering potentialimpacts on the soil structure, major problems from the landdisposal of stillage should not be observed, since the phosphoruscontent is usually scarce in soils due to its slow biogeochemicalcycling.

Finally, regarding the presence of potassium, low concentrationsare also naturally available to plants due to its high stability in thesoil structure, reflecting the need for mineral supplementation.Even the land application of low-potassium-content wastewaterstends to significantly increase its availability to crops, leading tohigher productivities. Considering specifically the reuse of stillagein agriculture, Gunkel et al. (2007) have measured a mean potas-sium concentration of 5.1 g kg�1 in fertigated fields, while theconcentrations in areas without fertigation reached about2.2 g kg�1. Pathak et al. (1999) have also reported expressive im-provements in the potassium availability in fertigated areas,ranging from 191.4 kg ha�1, in the control soil, to 2365 kg ha�1.However, such concentrations exceed considerably the potassiumrequirements of most crops e 185 kg ha�1 (WHO, 2006), whichimplies a large amount of surplus exchangeable potassium in fer-tigated areas, especially in cases lacking the proper technicalcriteria (i.e. application dosages based on the cation-exchange ca-pacity of the soil and on the delimitation of groundwater rechargeareas, complete physicochemical characterization of stillage andsoils, especially in terms of organic matter and nutrients, etc.).Mariano et al. (2009) and Rolim et al. (2013) have reported signif-icant rises in groundwater potassium concentrations after stillageland application (~10e380 mg L�1, Table 1), which could indicatethe soil saturation with Kþ ions.

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229220

Although few studies consider the interaction between highpotassium concentrations and the soil structure (Arienzo et al.,2012), some important effects should be pointed out. In short,potassium may act both as a soil dispersant or aggregator,depending on the mineralogical composition of the clays in thefertigated soils. In smectite-rich soils, potassium tends to promotethe aggregation of particles (Richards, 1954; Arienzo et al., 2009), asthe ions Kþ

firmly bind successive clay layers, making it difficult forwater molecules, other ions and organic radicals to penetrate theinterlayer space. In comparison with sodium, potassium ions pre-sent a lower hydration capacity, which leads to a smaller atomicradius and limits the spacing between layers. Indeed, Boek et al.(1995) have identified a greater hydration capacity in sodium-and lithium-rich anhydrous clays, so that such behavior enhancedclay swelling. On the contrary, the reluctance of Kþ ions to fullyhydrate proved to reduce the tendency of potassium-rich clays toexpand, confirming its role as a clay swelling inhibitor. Montes-Het al. (2003) have also observed greater hydration capacities inNa- and Li-saturated clays (bentonites), so that the adsorption ofwater to the mineral layers could be attributed to the formation ofwater multilayer around the cations and also to the water capillarycondensation. Actually the authors have observed that wateradsorption for K-saturated bentonite remains low when comparedwith other cation-saturated clays, including the ones bound todivalent cations (Mg2þ and Ca2þ). Such tendency have also beenreported by Bronick and Lal (2005), in which larger aggregates ofgreater stability have been associated with K-saturated soils than inthose saturated with divalent cations and sodium. Finally, Mohanet al. (1993) have observed similar results in sandstones contain-ing swelling and non-swelling clays, so that for both types of clayspotassium was characterized as less sensitizing (i.e. presentinglower hydration capacity) than sodium.

Additional benefits from the potassium input to soils have beendescribed by Robbins (1984), who has observed a reduction on theeffects of sodium on the physical structure of an illite-rich soil byincreasing the content of available Kþ. This pattern could beattributed to the preference of adsorption sites for Kþ in compari-son with Naþ and other ions, which was also indicated by Richards(1954). Levy and Torrento (1995) have reported that Kþ ions sorp-tion in smectite-rich soils was approximately 10 times greater thanfor Naþ, which suggests that potassium could improve the physicalstructure of Na-rich soils (e.g. by increasing soil permeability). Britoet al. (2007) have also observed an increase in the exchangeablepotassium concentration of three different soils after the applica-tion of sugarcane stillage. The authors have also reported an in-crease in Naþ concentrations in the deeper layers of the soils, sothat the displacement of such ions to the lower layers could beattributed to the Kþ supply through fertigation.

However, excessive concentrations of potassium should causethe same adverse effects than those from sodium, leading to thedispersion of particles and consequently reducing the soil perme-ability (Chen et al., 1983; Biswas et al., 1998; Kaushik et al., 2005;Arienzo et al., 2012). Gariglio (2008) has studied the fate of Kþions in soil by simulating the land application of stillage at differentdosages (0e320 m3 ha�1). The author has observed a significantbuild-up of potassium in the exchange sites of the soil, which hascontributed to high calcium and magnesium losses. Since Ca2þ andMg2þ ions enhance the cohesion of soil particles (Richards, 1954;Kaushik et al., 2005; Tejada and Gonzalez, 2006), such behaviortends to decrease soil stability by increasing the dispersion of itsaggregates. Yet regarding the study of Gariglio (2008), the authorhas associated exchangeable potassium percentage (EPP) valuesgreater than 5% to stillage application dosages as low as 30m3 ha�1.Kþ saturation in nutritionally balanced soils should not exceed 5%of the cation-exchange capacity, since adverse effects on the soil

osmotic potential could be generated (CETESB, 2006; Gariglio,2008). Considering stillage dosages of 320 m3 ha�1, EEP valuesreached up to 16%. Auerswald et al. (1996) have reported an in-crease in the soil erodibility by rising EPP in the ground. The build-up of Kþ ions has anticipated the runoff in about 5 min than theexpected (i.e. evidence of reductions on hydraulic conductivity), aswell as have increased the sediment concentrations by 15 g L�1 inthe water. In this case, the investigations allowed the authors tostudy/simulate a wide range of soils (65 types), slopes and rainfallconditions, leading to consistent results to understand the effect ofK on the physical properties of soils. In a previous study, Chen et al.(1983) have also investigated the influence of Kþ leaching on threedifferent soils (viz. loamy sand, light clay and heavy clay), so that forEPP values of 58e76% decreases of about 20% were observed on thehydraulic conductivity, regardless the soil mineral composition. Inshort, the enrichment of soils with Kþ ions has enhanced the for-mation of a dense network of clay microaggregates filling up thepore space. Similar results were reported in Arienzo et al. (2012),whose findings have also revealed reductions on the hydraulicconductivity of a smectite-rich soil by leaching solutions withdifferent Nþ/Kþ ratios. On the contrary, in previous studies Arienzoet al. (2009) have indicated that the dispersive effects from exces-sive potassium concentrations should be more evident in kaoliniticand illitic soils. Thus, since the effects of potassium (i.e. potassiumreadily available in colloidal particles and/or dissolved in the water)on the soil structural stability are not clearly defined by the liter-ature (Levy and Torrento, 1995; Arienzo et al., 2012), since differentpatterns have been reported, additional studies correlating sucheffects should be carried out, focusing on fertigated areas.

3.4. Contamination by metals: toxicity to plants and humanpopulations

Since the reference literature classifies stillage as a poor-metal-wastewater (Wilkie et al., 2000; Madej�on et al., 2001; Ramalho andAmaral Sobrinho, 2001; Macedo, 2005; Camilotti et al., 2007;Hartemink, 2008; Ribeiro et al., 2010), a lack of studies address-ing the occurrence and fate of toxic metals in fertigated areas iscommonly observed. However, specific analyses have revealed highconcentrations of metals in stillage samples, which demands spe-cial attention due to their toxicity to crops and human populationseventually supplied by contaminated water resources. Table 4 de-picts the concentration of metals in stillages from different feed-stocks, as well as compares such concentrations with referencevalues reported in normative instructions dealing with the waterdischarge and the agricultural reuse of wastewaters. Surprisingly,high concentrations of priority pollutants, such as cadmium, lead,nickel and zinc have been found in stillage samples, so that someharmful effects on the human health should be pointed out: cad-mium, chromium and nickel are carcinogenic elements, besidesaffecting the renal and gastrointestinal systems in long-termexposure (Metcalf & Eddy, 2003; Fu and Wang, 2011). Lead, cop-per and zinc also are harmful to the gastrointestinal system.Furthermore, the continuous exposure to high concentrations oflead could affect the central nervous system and inhibit basic cellfunctions (Fu andWang, 2011). Nandan et al. (1990) have found Pb,Zn and Cu concentrations of up 8.8, 11.8 and 15.7 mg L�1 (Table 4) insugarcane molasses stillage samples. Chandra et al. (2008b) havealso reported high concentrations for Pb, Zn and Cd in molassesstillages, reaching values of 4.4, 4.6 and 2.3 mg L�1 (Table 4).Similarly, Cu, Cd, Zn and Cr concentrations have reached values of3.12, 2.37,14.11 and 3.03mg L�1 in Chandra et al. (2009) (Table 4). InPrevina and Saravanan (2013) Zn and Cu concentrations of 11 and65 mg L�1 were also found in molasses stillages. Regardless thesource of such metals (i.e. soil composition, raw materials, types of

Table 4Metal concentrations in stillages from different feedstocks and reference values for the water discharge and land application.

Metal Normative instructionsa Stillage samplesa

Metcalf &Eddy (2003) b

WHO (2006) c Brasil (2011a) d Sugarcane juicee Sugarcane molassesf Corng Beeth

Al ne 5.0 ne 70.63 72.5 11.8 nd nd nd nd nd nd <1.0 2.51 ndCd 0.0011 0.01 0.2 nd 1.06 0.001 nd 0.5 2.281 2.37 nd nd nd (e) <0.114Pb 0.0056 5.0 0.5 0.44 (e) 0.04 1e8.8 0.75e1.5 4.446 1.46 nd nd nd (e) <0.114Cu 0.0049 0.2 1.0 0.59 (e) 0.67 1.7e15.7 0.75e1.0 0.955 3.12 65 0.195 0.17 0.165 2.4Cr 0.011 0.1 0,1 nd 0.15 0.06 nd <0.02 0.44 3.03 nd nd nd 0.021 <0.011Fe ne 5.0 15.0 60.22 97.5 15.37 36e43.5 0.01e0.05 84.01 184.01 4.3 0.661 8.12 6.49 258.318Mn ne 0.2 1.0 7.81 (e) 2.68 3e5.1 0.9e1.1 2.112 5.03 5.4 1.17 3.9 0.51 3.886Mo ne 0.01 ne nd 2.0 0.008 nd nd nd nd nd nd nd 0.017 ndNi 0.0071 0.2 2.0 nd 0.26 0.054 nd 2.8e3.1 1.241 2.24 nd 0.125 nd 0.013 ndZn 0.058 2.0 5.0 1.27 7.5 0.43 3.1e11.8 0.7 4.631 14.11 11 6.24 6.75 1.77 13.716

Notes: ne ¼ reference value not established; nd ¼ parameter not analyzed; (e) ¼ below the detection limit.a Concentrations in mg L�1.b Typical discharge limits for metals found in secondary effluent, according to US normative instructions.c Threshold levels of trace elements for crop irrigation.d Reference limits for effluent discharge into water bodies (maximum permissible values), according to Brazilian normative instructions.e References: Bianchi (2008), Mariano et al. (2009) and Fuess (2013).f References: Nandan et al. (1990), Pandey et al. (2003); Chandra et al. (2008a,b) and Previna and Saravanan (2013).g References: Agler et al. (2008), Alkan-Ozkaynak and Karthikeyan (2011) and Wilkinson (2011).h References: Tejada and Gonzalez (2006) and Tejada et al. (2007).

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 221

chemicals and machinery use in ethanol production), the highconcentrations observed in molasses stillages are enhanced by thecrystallization process in sugar production, at which water isremoved (Chandra et al., 2008b; Ensinas et al., 2009). Similar pat-terns are observed for salt concentrations in molasses stillages(Table 2), as previously discussed in Section 3.1. Consequently, theconcentrations of priority pollutants, as well as of other metals ingeneral, tend to be lower in less concentrated stillages, such as theones from sugarcane juice (Table 4).

Regarding toxicity to plants, high concentrations of aluminumshould be highlighted (70.6e72.5 mg L�1 for sugarcane juice stil-lages, Table 4), since it may reduce severely the nutrients uptake bythe plant roots due to structural modifications. Such negative ef-fects are enhanced under acidic conditions (pH < 5.5), due to thehigher solubility of aluminum, as well as of other metals in general(Petruzzelli, 1989). Indeed, the conditions propagated by the stil-lage land disposal tend to increase themobility of metals in the soil,based on the solubilization of minerals by the attack of acidiccompounds. Consequently, the leaching of important micro-nutrients, such as manganese and cobalt, may be observed in fer-tigated areas (Pant and Adholeya, 2007; Espa~na-Gamboa et al.,2011). Considering the effects of iron, excessive concentrationsmay contribute to soil acidification and also result in essentialnutrients losses, such as phosphorus and molybdenum, due to theformation of chemical complexes not assimilated by plants (USEPA,2004; WHO, 2006). Besides, high concentrations of iron promotethe formation of deposits on plants, equipment and buildings, aswell as stimulates stunted growing, limits tillering and causesnutritional disorders in plants (USEPA, 2004; Majerus et al., 2007).With respect to copper, toxic effects should already be observed forconcentrations lower than 1.0 mg L�1 (USEPA, 2004). Copper has akey role in redox reactions by acting on the mechanisms of electrontransport in the photosynthetic and cellular respiration processes,besides acting as a cofactor for many metallproteins (Yruela, 2005;An, 2006). Chandra et al. (2009) have observed the accumulation ofseveral toxic metals (Cu, Cd, Cr, Zn, Fe, Ni, Mn and Pb) in wheat andIndian mustard irrigated with a mixture of molasses stillage andtannery effluent, indicating the potential generation of healthhazards for humans and animals. Cd, Cr and Pb accumulation inwheat leaves has reached values as high as 2.12, 10.10 and12.18 mg kg�1, respectively. In mustard leaves similar patterns have

been observed, with Cr concentrations of 15.76 mg kg�1 in theleaves. Deficiencies on crop growth have also been described by theauthors, which could be explained by the toxicity of heavy metalsover the plant metabolism, leading to changes on the structuralconformation of proteins. Interesting findings have also been re-ported in Chandra et al. (2008a), in which the effects of sludgesamples from an anaerobic reactor treating molasses stillage onseed germination and growth parameters of green grass werestudied. Sludge amendments with garden soil in different con-centrations (10, 20, 40, 60, 80 and 100%, w/w) have been applied tothe crop. In soils amended with 10% (w/w) of stillage, positive ef-fects have been described, so that fertigation has induced thegrowth in root length, shoot length, number of leaves, biomass,photosynthetic pigment, protein and starch. However, for stillageconcentrations above 40% (w/w) reductions on all growth param-eters have been reported. Similarly to Chandra et al. (2009), theauthors have also attributed such limitations to the accumulation ofheavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) on the crop, as wellas to high concentrations of phenols and chlorides. Although in thiscase stillage has not been directly applied to soil, the high con-centrations of heavy metals found in the anaerobic sludge (e.g.Cr ¼ 8.12, Cu ¼ 118.96, Ni ¼ 27.2 and Zn ¼ 130.26 mg kg�1) alsoindicate that molasses stillages comprises a potential source oftoxic metals.

The occurrence of metals in stillage might be related to thefollowing factors: [i] soil mineral composition; [ii] characteristics ofethanol production process, including the types of chemicals usedand [iii] corrosion of metallic structures. The high aluminum andiron content found in stillages from the Brazilian sugarcane-to-ethanol industry e 11.8e72.5 and 15.4e97.5 mg L�1 (Bianchi,2008; Mariano et al., 2009; Fuess, 2013), respectively (Table 4) eare due to the predominant characteristics of tropical soils, inwhich the advanced degree of weathering solubilizes significantconcentrations ions Al3þ and Fe3þ from the minerals, speciallykaolinite, hematite and gibbsite (Alves, 2002; Costa et al., 2002).Particularly, corrosion represents the most probable source of toxicmetals in stillage, considering the use of acidic compounds andhigh temperatures in specific steps of ethanol production (USEPA,1986; Wilkie et al., 2000; Kumar and Chandra, 2004; Chandraet al., 2008b). In short, corrosion is enhanced during repeatedboiling of broth at low pH levels, leading to the concentration of

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229222

metallic compounds in the subsequent production steps of ethanol(Chandra et al., 2008b). Although tanks, pipes and heat exchangersare usually fabricated from corrosion-resistant alloys, the metalleaching from low quality materials is very likely to occur, espe-cially when old machinery is used, in order to enhance the releaseof heavy metals to the liquid fractions in ethanol plants.

Lastly, it is important to point out that the occurrence of hightoxic metal concentrations in stillage should not be considered arule, since the input of such compounds depends on specific con-ditions: corrosion of metallic structures, adsorption of metalsdirectly from soil and their concentration in stillage due to waterremoval in steps previous to distillation (Wilkie et al., 2000;Chandra et al., 2008b). In fact, as observed in Table 4, concentra-tions of priority pollutants in sugarcane juice and corn stillagestend to be low. However, the correct management of stillage isstrictly related to its regular and complete physicochemical char-acterization, regardless the aspects of its treatment and finaldestination. It is noteworthy that the correct management of stil-lage (i.e. choice of the most suitable practices for its treatment,reuse and disposal) depends on a global trade-off, which must takeinto consideration not only technical and economical factors, butalso the energetic and environmental ones (Willington andMarten,1982; Borrero et al., 2003; Cruz, 2011; Fuess and Garcia, 2013).Further information on such topic is presented in Section 4.

4. Outlook: options for the correct management of stillage

Despite the range of potential adverse impacts, the land disposalof stillage still presents attractive possibilities that should behighlighted, such as nutrient and water recycling and the lowerenergy consumption associated with a reduced production ofsynthetic fertilizers. Regarding specifically the water consumptionin sugarcane fields, approximately 150 m3 of fresh water are savedper hectare in each application, which corresponds to the averagestillage application rate (BNDES and CGEE, 2008; Silva et al., 2014).Based on the total sugarcane harvest area in Brazil (~8.5 � 106 ha,2012/2013, CONAB, 2013), this number reaches approximately 1.3billion liters. Furthermore, fertigation also provides economicaladvantages when compared to other technologies, including lowinitial investment and maintenance cost and fast application(Santana and Machado, 2008; Cruz, 2011). However, such benefitsshould not be used as the sole justification for the indiscriminatedisposal of stillage into agricultural fields, so that this practicemight be a palliative alternative providing a false impression ofsolving efficiently the management of stillage.

In comparison with domestic sewage, stillage presents asignificantly higher polluting load, as previously observed in Fig. 1.Thus, its adequacy on an environmental basis prior to the finaldisposal seems to be an immediate and logical option. However,focusing on the Brazilian case, while several technical and norma-tive documents address alternatives for the treatment and properreuse of domestic wastewaters and sewage sludge (ABNT, 1992,1993, 1997; Brasil, 2006), the reference literature lacks this aspectfor stillage, as well as for other agro-industrial wastewaters. A fewtechnical regulations define some permissible limits for thedischarge of industrial effluents into sewage collection systems(S~ao Paulo, 1976; ABNT, 1987). However, design criteria for thetreatment unities (e.g. physicochemical and biological reactors) inindustrial plants are not considered. Additionally, since distilleriesare mostly located at rural areas, the eventual discharge of stillageinto sewage systems comprises an economically unfeasible prac-tice, considering the expenses with both effluent transportationand expansion of existing treatment plants (Willington andMarten,1982). Regarding specifically legislations dealing with the man-agement of stillage in Brazil, its direct or indirect discharge into

water bodies was prohibited by a federal law at the end of the 1970s(Brasil, 1978). Currently, one of the few regulatory instructionsdealing with the land disposal of stillage (CETESB, 2006) bases thecalculation of the dosage only on the potassium content in thewastewater. The maximum potassium concentration in soil shouldnot exceed 5% of its cation-exchange capacity, so that when thislimit is reached, stillage application should be restricted to sup-plying Kþ in function of its average use by the crop (185 kg ha�1)(CETESB, 2006). In this context, the high concentrations of organicmatter, chlorides, sulfates and other salts are not properlyconsidered.

Therefore, based on the risks associated with the impropermanagement of stillage we suggest that two aspects of majorimportance must be considered, based on recommendations forboth the government and scientific community. Firstly, the estab-lishment of more restrictive laws, either for the sucro-energeticsector or for the agro-industry sector in general, which must takeinto consideration a wider range of physicochemical parametersused to define the correct stillage (or other wastewaters) dosages.The characterization of soil properties (e.g. organic matter and ni-trogen content, cation-exchange capacity, etc.) and the delimitationof groundwater recharge areas also comprise important aspects tomake the reuse of stillage environmentally feasible. Secondly, theimplementation of treatment plants in distilleries should also belegally regulated, as stillage seems to be suitable to the applicationof several technologies. Thus, we should highlight the importancein conducting additional studies on the adverse effects of fertiga-tion in the long-term, considering specifically the collection andanalysis of field data. Such studies could provide the basis forregulating the effluent management in the ethanol industry.

With respect to the treatment options, as previously pointedout, physicochemical (e.g. coagulationeflocculation, adsorption)and biological (e.g. anaerobic and aerobic digestion) processes maybe successfully applied to stillage. Studies on the application ofphytoremediation (Billore et al., 2001; Valderrama et al., 2002;Singh et al., 2005; Olguín et al., 2008; Sohsalam andSirianuntapiboon, 2008) and advance oxidation processes(Sangave and Pandit, 2004, 2006; Sangave et al., 2007; Yavuz, 2007;Asaithambi et al., 2012) also indicate their suitability to treat stil-lage, however, most of approaches are still at experimental stage.Thus, further research is needed to make it feasible the applicationof such technologies in full-scale stillage plants (Pant and Adholeya,2007; Satyawali and Balakrishnan, 2008), so that in this sectionspecial attention is given to consolidated treatment technologies:coagulationeflocculation, aerobic and anaerobic digestion. Furtherinformation on each type of process may be found in the referenceliterature specifically dealing with the treatment of stillages,including Pant and Adholeya (2007), Satyawali and Balakrishnan(2008), Strong and Burgess (2008), Mohana et al. (2009) andEspa~na-Gamboa et al. (2011).

Table 5 presents the treatment performances of some technol-ogies applied to stillage, so that the selection of the most appro-priate management alternative depends on a global trade-off, aspreviously discussed. Physicochemical methods, regarding specif-ically coagulationeflocculation (CF), comprise robust and consoli-dated treatment technologies (Bratby, 2006; Rodrigues et al., 2013).In such processes a variety of metallic salts (e.g. ferric chloride andsulfate, aluminum chloride and sulfate)may be used to promote thedestabilization of colloidal particles in the wastewater, in order toenhance its subsequent removal by sedimentation or flotation(Zayas et al., 2007; Ryan et al., 2008; Liang et al., 2009, 2010;Espa~na-Gamboa et al., 2011). Since stillage contains a highorganic content, the application of CF to the treatment of raw stil-lage is economically unfeasible, based on the high demand forchemicals and energy, as well as on the need for disposing high

Table 5Technological approaches for the treatment of stillage considering conventional (physicochemical and biological) and oxidative processes.

Reference Treatment process Removal efficiencies

Singletechnologies

Costa et al. (1986), Goyal et al. (1996),Shivayogimath and Ramanujam (1999),Acharya et al. (2008)

Anaerobic digestion COD z 80%

Bories et al. (1988) Anaerobic digestion COD ¼ 73.8%, BOD ¼ 97.1%de Bazúa et al. (1991) Aerobic digestion COD ¼ 70%, BOD ¼ 95%Vlissidis and Zouboulis (1993),Agler et al. (2008)

Anaerobic digestion COD z 90%

Billore et al. (2001) Phytoremediation COD ¼ 64%, BOD ¼ 85%, TSa ¼ 42%,Ptotal ¼ 76%, TKNb ¼ 36%

Cibis et al. (2002) Aerobic digestion COD ¼ 76.7%Valderrama et al. (2002) Phytoremediation

(microalgae followedby macrophytes)

COD ¼ 61%, NH3 ¼ 71.6%,Ptotal ¼ 28%, color ¼ 52%

Jim�enez et al. (2003) Aerobic digestion COD ¼ 52.1%, color ¼ 41%Olguín et al. (2008) Phytoremediation

(subsurface flowconstructed wetland)

COD z 80%, BOD z 87.3%, TKNb ¼ 76%,NO3

- z 57%, SO42� ¼ 69%

Sohsalam and Sirianuntapiboon (2008) Phytoremediation(surface flowconstructed wetland)

COD ¼ 67%, BOD ¼ 89%, Ptotal ¼ 76%,NO3

- ¼ 95%, color ¼ 77%

Ferreira et al. (2011) Aerobic digestion COD ¼ 82.8%, BOD ¼ 75.3%, color ¼ 99.2%Lutoslawski et al. (2011) Aerobic digestion COD ¼ 83.7e88.7%, BOD ¼ 95.8e99.5%

Combinedtechnologies

Chandra and Singh (1999) Anaerobic digestionþ coagulationeflocculation

COD ¼ 97%, BOD ¼ 97%, color ¼ 96%

Ghosh et al. (2002) Anaerobic digestionþ aerobic digestion

COD ¼ 66%, color ¼ 60%

Pandey et al. (2003) Anaerobic digestionþ coagulationeflocculation

COD ¼ 87%, BOD ¼ 92%, color ¼ 99%

Sangave and Pandit (2004, 2006) Ultrasound þ aerobic digestion COD ¼ 60%Zayas et al. (2006) Anaerobic digestion

þ coagulationeflocculationCOD ¼ 65%, color ¼ 98.4%, turbidity ¼ 99.2%

Sangave et al. (2007) Ozonation þ aerobic digestionþ ozonation

COD ¼ 79%, color z 100%

Yavuz (2007) Electrocoagulation þ electrofenton COD ¼ 92.6%, TOCc ¼ 88.7%Zayas et al. (2007) Anaerobic digestion þ coagulation

eflocculation þ electrochemical oxidationCOD > 95%, color z 100%, turbidity z 100%

Ryan et al. (2008) Anaerobic digestion þ coagulationeflocculation

COD ¼ 80%, color ¼ 88%

Tondee et al. (2008) Anaerobic digestion þ aerobicdigestion

COD ¼ 88%, BOD ¼ 77.4%, color ¼ 80%

Liang et al. (2009) Anaerobic digestionþ coagulationeflocculation

COD ¼ 89%, color ¼ 98%

Liang et al. (2010) Anaerobic digestionþ coagulationeflocculation

COD ¼ 85%, color ¼ 96%

Asaithambi et al. (2012) Ozonation þ electrocoagulation COD ¼ 83%, color z 100%

a Notes: TS ¼ Total Solids.b TKN ¼ Total Kjeldahl Nitrogen (Norg þ NH3).c TOC ¼ Total Organic Carbon.

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 223

volumes of the organic matter- and metal-rich sludge generatedwithin the process (Mohana et al., 2009). Alternatives for the use ofinorganic salts include the application of natural coagulants andpolymers (e.g. starch, chitosan, tannins and specific seeds, such asthe ones from Moringa oleifera) to promote the aggregation oforganic compounds (Xing et al., 2005; Girardi, 2009; Prasad, 2009;Souza, 2010), which may be advantageous in both environmentaland economical aspects: reduction/elimination of using metalliccompounds, generation of less toxic sludges and increased savingsdue to using smaller amounts of chemicals (Bratby, 2006;Rodrigues et al., 2013). However, additional research is needed toprovide a better understanding on the use of natural compounds instillage CF, based on the establishment of optimal dosages anddesign criteria.

Regarding biological processes, the aerobic degradation of theorganic compounds present in stillage may be successfully ach-ieved by different microorganisms, such as fungi (Jim�enez et al.,2003; Tondee et al., 2008; Singh and Dikshit, 2010; Ferreira et al.,2011), bacteria (Cibis et al., 2002; Ghosh et al., 2002; Krzywonos

et al., 2009) and mixed consortiums (Nudel et al., 1987; de Bazúaet al., 1991; Kaushik et al., 2010; Lutoslawski et al., 2011). deBazúa et al. (1991), Ferreira et al. (2011) and Lutoslawski et al.(2011) have reported COD and BOD reductions of about 80 and90% (Table 5), respectively, by using aerobic processes to treatstillages from different feedstocks. Particularly, Ferreira et al. (2011)have also indicated reductions in stillage color of up to 99.2%(Table 5). Although high organic matter and average-to-high colorremovals may result from stillage aerobic digestion, the high spe-cific growth rates of aerobic microbial populations (i.e. excessivesludge generation) in association with the high demand for aera-tion also limit its direct application to raw stillages (Ni et al., 1993;Vlissidis and Zouboulis, 1993; Wilkie et al., 2000; Chernicharo,2007; Chan et al., 2009; Mohana et al., 2009). It is estimated thateach 1 kg of COD input into aerobic reactors generates 0.5e0.6 kg ofCOD in terms of microbial biomass (Ni et al., 1993; Chernicharo,2007), which could lead to annual sludge productions of up to85,400 tonnes in full-scale aerobic stillage treatment plants (e.g.activated sludge). Such calculation is based on the theoretical

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229224

aerobic sludge generation from sugarcane juice stillage (COD of30 g L�1, Wilkie et al., 2000) at daily flowrates of 13,000 m3 (Diaset al., 2011). For more concentrated stillages, such as the onesfrom molasses, corn, beet and cassava (Fig. 1), sludge generationcould reach values greater than 100,000 tonnes per year. Thus,aerobic digestion, as well as coagulationeflocculation, compriseefficient options as post-treatment processes for stillage (Satyawaliand Balakrishnan, 2008; Mohana et al., 2009; Espa~na-Gamboaet al., 2011), especially when anaerobic digestion is used as thecore treatment technology.

In short, anaerobic digestion concentrates important advantagesover the other technologies, regarding mainly its potential togenerate energy from biogas. Borzacconi et al. (1995) have indi-cated that a minimum-to-average energy recovery capacity of50e60% could be obtained from biogas combustion in industrialplants, so that 85e95% of the organic matter found in stillage couldbe converted to methane under optimal operating conditions (Pantand Adholeya, 2007; Wilkie, 2008). Studies based on the applica-tion of anaerobic digestion to stillage in the corn-to-ethanol in-dustry have estimated potential reductions on fossil fuelsconsumption ranging from 43 to 65% (Agler et al., 2008; Cassidyet al., 2008; Khanal, 2008; Schaefer and Sung, 2008). Regardingsugarcane-to-ethanol industry, the use of fossil fuels in distilleriescould be fully ceased by producing energy from the biogas gener-ated in stillage anaerobic digestion (Fuess and Garcia, 2014). Basedon the Brazilian case, and considering the anaerobic conversion ofthe total volume of stillage from sugarcane ethanol (season 2009/2010), the bioenergy potentially produced from biogas could reachabout 7.5% (6.9� 106MWh) of the electricity generated from Itaipu,the world's largest hydroelectric plant (Moraes et al., 2014). Thefinancial return from such scenarios is also attractive to the ethanolindustry, since at least US$ 17 to 30 million dollars could beannually saved in large-scaled corn- and sugarcane-based distill-eries, respectively (Schaefer and Sung, 2008; Fuess and Garcia,2014). In comparison with aerobic digestion, additional advan-tages from using anaerobic processes include the low sludge gen-eration, besides reduced energy consumption (Vlissidis andZouboulis, 1993; Metcalf & Eddy, 2003; Chernicharo, 2007;Mohana et al., 2009). Biomass production may be 3e5 timeslower in anaerobic systems (Chernicharo, 2007). Regarding energyconsumption, while energetic requirements for aeration in aerobicreactors may reach up to 2.0 kWh kg�1COD (Khanal, 2008; McCartyet al., 2011; Cheng et al., 2012), at least 2.6e2.8 kWh kg�1COD couldbe obtained from biogas (Fuess and Garcia, 2014) in ethanol plants.

With respect to the treatment performance of anaerobic re-actors applied to stillage, COD and BOD reductions as high as 90 and95% (Bories et al., 1988; Vlissidis and Zouboulis,1993; Acharya et al.,2008; Agler et al., 2008, Table 5) may be obtained. However, theeffluents from anaerobic reactors treating stillage still present highorganic content and color, so that its direct reuse in agricultureshould also be avoided (Chernicharo, 2007; Pant and Adholeya,2007; Mohana et al., 2009; Espa~na-Gamboa et al., 2011;Rodrigues et al., 2013). In Jain et al. (2005) and Kaushik et al.(2005) the remaining COD and BOD values in the anaerobicallytreated effluent ranged from 30.1e31.0 and 4.8e8.4 g L�1, respec-tively, comprising values much greater than the recommendedlimit for organic matter disposal in soils (~400 mg L�1 as BOD,WHO, 2006). Most of this remaining organic content in stillage afteranaerobic digestion is composed by recalcitrant substances, such asphenolic compounds and melanoidins (Wilkie et al., 2000; Pantand Adholeya, 2007; Strong and Burgess, 2008; Mohana et al.,2009; Espa~na-Gamboa et al., 2011), which may explain the highresidual color. Besides, another limitation associated to anaerobicprocesses is the unsatisfactory removal of nutrients (e.g. phos-phorus and nitrogen), since the low growth rate of methanogens

implies a low nutrient uptake during the conversion process(Metcalf & Eddy, 2003; Chernicharo, 2007). For instance, yetregarding the study of Jain et al. (2005) and Kaushik et al. (2005),nitrogen and potassium concentrations in the post-methanatedstillage were kept at about 2000 and 6000 mg L�1. Such valuesare equivalent or even higher than the nutrient content found inless concentrated sugarcane juice raw stillages (Costa et al., 1986;Ferreira et al., 2011; Fuess, 2013; Rolim et al., 2013). Thus,although the use of anaerobic digestion as a core technology totreat stillage should be encouraged, no single treatment technologycan be efficiently applied to its absolute environmental suitability(Mohana et al., 2009).

Some studies indicate high organic matter (60e90% as COD) andcolor (60e80%) removals from stillage by associating anaerobic andaerobic digestion (Ghosh et al., 2002; Tondee et al., 2008, Table 5).However, especial attention should be directed to the combinationbetween anaerobic conversion and coagulationeflocculation, sinceCOD, BOD and color removals may exceed 90% under optimalconditions in both processes (Chandra and Singh, 1999; Pandeyet al., 2003; Zayas et al., 2007; Liang et al., 2009, Table 5). The op-tion for coagulationeflocculation as a post-treatment step shouldenhance the removal of recalcitrant organic compounds, especiallymelanoidins (Liang et al., 2009, 2010), in addition to the completedecolorization of stillage (Pandey et al., 2003; Zayas et al., 2007).Melanoidins, as well as humic and tannic acids, have large molec-ular structures and anti-oxidant properties (Pant and Adholeya,2007; Espa~na-Gamboa et al., 2011), so that their degradation un-der anaerobic conditions is not expected to occur. Specific aerobicmicroorganisms are able to degrade such recalcitrant compounds,however, treatment performances regarding decolorization may beinstable, as well as the occasional formation of hazardous by-products may also take place (Liang et al., 2009). Generally, thedegradation of melanoidins (and consequently, color removal) inbiological systems reaches maximum values ranging from 6 to 7%(Satyawali and Balakrishnan, 2008; Mohana et al., 2009). On thecontrary, the large molecules negatively charged of such com-pounds make them behave as colloidal particles in solution, whichfacilitates the action of coagulants in destabilizing them and en-hances the process of decolorization (Liang et al., 2010; Reali et al.,2013). Thus, further improvements on the final quality of effluentsfrom anaerobic reactors treating stillage, especially in terms of colorremoval, may be achieved by combining coagulationeflocculationto anaerobic digestion, in order to make stillage suitable for directland disposal.

Additional alternatives to provide a more adequate agriculturalreuse of stillage, either for raw (less concentrated) or post-methanated effluents, include the production of soil bio-amendments by combining stillage with phytomass-rich solidwastes (Madej�on et al., 2001; Kaushik et al., 2005). Such practicetends to improve the concentrations of readily available carbon andnutrients supplied to soils, as in the preparation of the compostsreductions are observed on the stillage putrescible organic matter(Madej�on et al., 2001). Furthermore, eventual deficiencies in thereadily available carbon content of stillage e characteristic oftenobserved in effluents from molasses (Pant and Adholeya, 2007) eare offset by the organic matter found in the vegetal biomass(Tejada and Gonzalez, 2006). Madej�on et al. (2001) have assessedthe effects of disposing beet stillage co-composted with differentsolid wastes (i.e. grape-marc, olive pressed cake and cotton gintrash) to a corn/sugar-beet/sunflower system cultivated on a sandysoil. Regardless the waste used, the soil bioamendment hasincreased crop yield, as well as the amount of oxidizable carbon insoil (i.e. increasing organic matter content). Beneficial effects fromcombining post-methanated sugarcane molasses stillage with res-idues (farmyard manure, brassica residues and rice husk) have also

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 225

been reported by Kaushik et al. (2005). In this case, the authorshave associated improved soil properties, successful germinationand improved seedling growth of pearl millet, and increased soilenzymatic activities to the use of bioamendments, which has alsoled to reductions on the high concentrations of Naþ and Kþ ionsavailable in soil. Such reductions are related to the chelation ofcations to organo-colloids formed by decomposing biomass, whichcontributes to limit the action of dispersive agents in soil. Similarresults may also be found in Tejada and Gonzalez (2006), in whichthe use of beet stillage composted with cotton gin crushed composthas resulted in several positive impacts to a sandy soil. The authorshave observed reductions on soil bulk density (1.46e1.20 Mg m�3)and consequently on soil structural instability, in addition to anincrease in microbial biomass. In short, this study has associatedimproved flocculation of clay particles to the increase in microbialactivity, based on the role of excreted metabolites as soil aggre-gators. The use of sugarcane stillage combinedwith sugarcane trash(tops and leaves from the plant) and/or filter cake (residue from thebroth filtration in rotating filters) also provides positive impacts tosoils and crops, recycling nutrients and controlling the occurrenceof weeds and plant diseases (Cavallet et al., 2012). However, thesuccess of such practice also depends on a balance between thequantities of liquid (stillage) and solid residues during compostproduction, otherwise similar effects to those observed fromapplying raw stillage should be observed (Kaushik et al., 2005). Forinstance, the best results observed by Kaushik et al. (2005) wereassociated to stillages diluted to 50%, so that the use of undilutedstillage to produce the bioamendments has increased significantlyNaþ concentrations in soil, as well as inhibited soil microbialactivity.

Finally, although fertigationwith stillage might be classified as alocal practice, since it is more common in countries like Brazil andIndia, its consequences on the environmental quality are of greatinterest in an international context. Currently the environmentalaspects of a given product (in our case, ethanol) or service arerelevant to their commercialization in the external market, so thatthe analysis of a product's life cycle may dictate the success orfailure of its sale. Thus, considering future implications, the po-tential adverse impacts from the continuous land application ofstillage could adversely affect the competitiveness of ethanol pro-duction from sugarcane, based on the inclusion of environmentalcosts in the price of ethanol.

Acknowledgments

The authors are grateful to the S~ao Paulo Research Foundation(Fapesp), process number 2010/04101-8, and to the NationalCouncil for Scientific and Technological Development (CNPq),process 470010/2013-4, for supporting the development of thisstudy. We are also grateful to the reviewers of the Journal ofEnvironmental Management, whose suggestions were important toimprove the quality of this review.

References

ABNT, 1987. NBR 9800: Crit�erios para lançamento de efluentes líquidos industriaisno sistema coletor público de esgoto sanit�ario. Associaç~ao Brasileira de NormasT�ecnicas, Rio de Janeiro (in Portuguese).

ABNT, 1992. NBR 12209: Projeto de estaç~oes de tratamento de esgoto sanit�ario.Associaç~ao Brasileira de Normas T�ecnicas, Rio de Janeiro (in Portuguese).

ABNT, 1993. NBR 7229: Projeto, construç~ao e operaç~ao de sistemas de tanquess�epticos. Associaç~ao Brasileira de Normas T�ecnicas, Rio de Janeiro (inPortuguese).

ABNT, 1997. NBR 13969: Tanques s�epticos e unidades de tratamento complementare disposiç~ao final dos efluentes líquidos e projeto, construç~ao e operaç~ao.Associaç~ao Brasileira de Normas T�ecnicas, Rio de Janeiro (in Portuguese).

Acharya, B.K., Mohana, S., Madamwar, D., 2008. Anaerobic treatment of distilleryspent wash e a study on upflow anaerobic fixed film bioreactor. Bioresour.Technol. 99, 4621e4626.

Agler, M.T., Garcia, M.L., Lee, E.S., Schlicher, M., Angenent, L.T., 2008. Thermophilicanaerobic digestion to increase the net energy balance of corn grain ethanol.Environ. Sci. Technol. 42, 6723e6729.

Alkan-Ozkaynak, A., Karthikeyan, K.G., 2011. Anaerobic digestion of thin stillage forenergy recovery and water reuse in corn-ethanol plants. Bioresour. Technol.102, 9891e9896.

Alves, M.E., 2002. Atributos mineral�ogicos e eletroquímicos, adsorç~ao e dessorç~aaode sulfato em solos paulistas. Ph.D. thesis. University of S~ao Paulo, Piracicaba,SP, Brazil (in Portuguese).

An, Y.J., 2006. Assessment of comparative toxicities of lead and copper using plantassay. Chemosphere 62, 1359e1365.

Andalib, M., Hafez, H., Elbeshbishy, E., Nakhla, G., Zhu, J., 2012. Treatment of thinstillage in a high-rate anaerobic fluidized bed reactor (AFBR). Bioresour. Tech-nol. 121, 411e418.

Arienzo, M., Christen, E.W., Quayle, W., Kumar, A., 2009. A review of the fate ofpotassium in the soil-plant system after land application of wastewaters.J. Hazard. Mater. 164, 415e422.

Arienzo, M., Christen, E.W., Jayawardane, N.S., Quayle, W.C., 2012. The relative ef-fects of sodium and potassium on soil hydraulic conductivity and implicationsfor winery wastewater management. Geoderma 173e174, 303e310.

Arthington, A.H., Marshal, J.C., Rayment, G.E., Hunter, H.M., Bunn, S.E., 1997. Po-tential impact of sugarcane production on riparian and freshwater environ-ments. In: Keating, B.A., Wilson, J.R. (Eds.), Intensive Sugarcane Production:Meeting the Challenges beyond 2000. CAB International, Wallingford,pp. 403e412.

Asadi, M.E., Clemente, R.S., Gupta, A.D., Loof, R., Hansen, G.K., 2002. Impacts offertigation via sprinkler irrigation on nitrate leaching and corn yield in an acid-sulphate soil in Thailand. Agr. Water Manage. 52, 197e213.

Asaithambi, P., Susree, M., Saravanathamizhan, R., Matheswaran, M., 2012. Ozoneassisted electrocoagulation for the treatment of distillery effluent. Desalination297, 1e7.

Athanasopoulos, N., 1987. Anaerobic treatment of beet molasses alcoholic fermen-tation wastewater in a downflow filter. Resour. Conserv. 17, 147e150.

Auerswald, K., Kainz, M., Angermüller, S., Steindl, H., 1996. Influence of exchange-able potassium on soil erodibility. Soil Use Manag. 12, 117e121.

Ayers, R.S., Westcot, D.W., 1999. A qualidade da �agua na agricultura. Estudos FAO.Irrigaç~ao e Drenagem 29, UFPB, Campina Grande.

B�aez-V�asquez, M.A., Demain, A.L., 2008. Ethanol, biomass, and Clostridia. In:Wall, J.D., Harwood, C.S., Demain, A. (Eds.), Bioenergy. ASM Press, WashingtonDC, pp. 49e54.

Banu, J.R., Kaliappan, S., Rajkumar, M., Beck, D., 2006. Treatment of spent wash inanaerobic mesophilic suspended growth reactor. J. Environ. Biol. 27, 111e117.

Batalha, B.H.L., Parlatore, A.C., 1993. Controle da qualidade de �agua para consumohumano: bases conceituais e operacionais, first ed. CETESB, S~ao Paulo (inPortuguese).

Berding, N., Hurney, A.P., 2005. Flowering and lodging, physiological-based traitsaffecting cane and sugar yield. What do we know of their control mechanismsand how do we manage them? Field Crop Res. 92, 261e275.

Bernstein, L., 1975. Effects of salinity and sodicity on plant growth. Annu. Rev.Phytopathol. 13, 295e312.

Bianchi, S.R., 2008. Avaliaç~ao química de solos tratados com vinhaça e cultivadoscom alfafa. M.Sc. dissertation.. Federal University of S~ao Carlos, S~ao Carlos, SP,Brazil (in Portuguese).

Billore, S.K., Singh, N., Ram, H.K., Sharma, J.K., Singh, V.P., Nelson, R.M., Dass, P., 2001.Treatment of a molasses based distillery effluent in a constructed wetland incentral India. Water Sci. Technol. 44, 441e448.

Biswas, T.K., Higginson, F.R., Shannon, I., 1998. Effluent nutrients management andresource recovery in intensive rural industries for the protection of naturalwaters. In: Proceedings of International Specialized Conference on WaterQuality and its Management, New Delhi, pp. 29e38.

Biswas, A.K., Mohanty, M., Hati, K.M., Misra, A.K., 2009. Distillery effluents effect onsoil organic carbon and aggregate stability of a Vertisol in India. Soil Till. Res.104, 241e246.

BNDES, CGEE, 2008. Bioetanol de cana-de-açúcar: energia para o desenvolvimentosustent�avel, first ed. Banco Nacional de Desenvolvimento Economico e Social,Rio de Janeiro (in Portuguese).

Boek, E.S., Coveney, P.V., Skipper, N.T., 1995. Monte Carlo molecular modelingstudies of hydrated Li- Na-, and K- smectites: understanding the role of po-tassium as a clay swelling inhibitor. J. Am. Chem. Soc. 117, 12608e12617.

Boopathy, R., Tilche, A., 1991. Anaerobic digestion of high strength molasseswastewater using hybrid anaerobic baffled reactor. Water Res. 25, 785e790.

Bories, A., Raynal, J., Bazile, F., 1988. Anaerobic digestion of high-strength distillerywastewater (cane molasses stillage) in a fixed-film reactor. Biol. Waste 23,251e267.

Borrero, M.A.V., Pereira, J.T.V., Miranda, E.E., 2003. An environmental managementmethod for sugar cane alcohol production in Brazil. Biomass Bioenerg. 25,287e299.

Borzacconi, L., L�opez, I., Vi~nas, M., 1995. Application of anaerobic digestion to thetreatment of agroindustrial effluents in Latin America. Water Sci. Technol. 32,105e111.

Brasil, 1978. Portaria/GM MINTER n. 323, de 29 de novembro de 1978 (inPortuguese).

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229226

Brasil, 2005. Resoluç~ao Conama n. 357, de 17 de março de 2005. Disp~oe sobre aclassificaç~ao dos corpos de �agua e diretrizes ambientais para o seu enqua-dramento, bem como estabelece as condiç~oes e padr~oes de lançamento deefluentes, e d�a outras previdencias (in Portuguese).

Brasil, 2006. Resoluç~ao Conama n. 375, de 29 de agosto de 2006. Define crit�erios eprocedimentos, para o uso agrícola de lodos de esgoto gerados em estaç~oes detratamento de esgoto sanit�ario e seus produtos derivados, e d�a outras pro-videncias (in Portuguese).

Brasil, 2008. Resoluç~ao Conama n. 396, de 3 de abril de 2008. Disp~oe sobre aclassificaç~ao e diretrizes ambientais para o enquadramento das �aguas sub-terraneas e d�a outras providencias (in Portuguese).

Brasil, 2011a. Resoluç~ao Conama n. 430, de 13 de maio de 2011. Disp~oe sobre ascondiç~oes e padr~oes de lançamento de efluentes, complementa e altera aResoluç~ao n, 357, de 17 de março de 2005, do Conama (in Portuguese).

Brasil, 2011b. Portaria MS n. 2914, de 12 de dezembro de 2011. Disp~oe sobre osprocedimentos de controle e de vigilancia da qualidade da �agua para consumohumano e seu padr~ao de potabilidade (in Portuguese).

Bratby, J., 2006. Coagulation and Flocculation in Water and Wastewater Treatment.IWA Publishing, London.

Braun, R., Huss, S., 1982. Anaerobic filter treatment of molasses distillery slops.Water Res. 16, 1167e1171.

Brito, F.L., Rolim, M.M., Silva, J.A.A., Pedrosa, E.M.R., 2007. Qualidade do percolado desolos que receberam vinhaça em diferentes doses e tempo de incubaç~ao. Rev.bras. eng. agríc. ambient. 11, 318e323 (in Portuguese).

Brito, F.L., Rolim, M.M., Pedrosa, E.M.R., 2009. Efeito da aplicaç~ao de vinhaça nas car-acterísticas de solos da zona da mata de Pernambuco. Agr�aria 4, 456e462 (inPortuguese).

Bronick, C.J., Lal, R., 2005. Soil structure and management: a review. Geoderma 124,3e22.

Camilotti, F., Marques, M.O., Andrioli, I., Silva, A.R., Tasso Jr., L.C., Nobile, F.O., 2007.Acúmulo de metais pesados em cana-de-açúcar mediante a aplicaç~ao de lodode esgoto e vinhaça. Eng. Agríc. 27, 284e293 (in Portuguese).

Carmo, J.B., Filoso, S., Zotelli, L.C., Sousa Neto, E.R., Pitombo, L.M., Duarte-Neto, P.J.,Vargas, V.P., Andrade, C.A., Gava, G.J.C., Rossetto, R., Cantarella, H., Neto, A.E.,Martinelli, L.A., 2013. Infield greenhouse gas emissions from sugarcane soilBrazil: effects from synthetic and organic fertilizer application and crop trashaccumulation. GCB Bioenergy 5, 267e280.

Cassidy, D.P., Hirl, P.J., Belia, E., 2008. Methane production from ethanol co-productsin anaerobic SBRs. Water Sci. Technol. 58, 789e793.

Cavallet, O., Junqueira, T.L., Dias, M.O.S., Jesus, C.D.F., Matelatto, P.E., Cunha, M.P.,Franco, H.C.J., Cardoso, T.F., Maciel Filho, R., Rossell, C.E., Bonomi, A., 2012.Environmental and economic assessment of sugarcane first generation bio-refineries in Brazil. Clean Tech. Environ. Policy 14, 399e410.

CETESB, 2006. Norma P4.231: Vinhaça e Crit�erios e procedimentos para aplicaç~ao nosolo agrícola. Companhia Ambiental do Estado de S~ao Paulo, S~ao Paulo (inPortuguese).

CGEE, 2009. Bioetanol combustível: uma oportunidade para o Brasil, first ed. Centrode Gest~ao e Estudos Estrat�egicos, Brasília (in Portuguese).

Chan, Y.J., Chong, M.F., Law, C.L., Hassell, D.G., 2009. A review on anaerobic-aerobictreatment of industrial and municipal wastewater. Chem. Eng. J. 155, 1e18.

Chandra, R., Singh, H., 1999. Chemical decolorization of anaerobically treated dis-tillery effluent. Indian J. Environ. Prot. 19, 833e837.

Chandra, R., Yadav, S., Mohan, D., 2008a. Effect of distillery sludge on seed germi-nation and growth parameters of green grass (Phaseolus mungo L.). J. Hazard.Mater. 152, 431e439.

Chandra, R., Yadav, S., Bharagava, R.N., Murthy, R.C., 2008b. Bacterial pretreatmentenhances removal of heavy metals during treatment of post-methanated dis-tillery effluent by Typha angustata L. J. Environ. Manage. 88, 1016e1024.

Chandra, R., Bharagava, R.N., Yadav, S., Mohan, D., 2009. Accumulation and distri-bution of toxic metals in wheat (Triticum aestivum L.) and Indian mustard(Brassica campestris L.) irrigated with distillery and tannery effluents. J. Hazard.Mater. 162, 1514e1521.

Chen, Y., Banin, A., Borochovitch, A., 1983. Effect of potassium on soil structure inrelation to hydraulic conductivity. Geoderma 30, 135e147.

Cheng, K.Y., Ho, G., Cord-Ruwisch, R., 2012. Energy-efficient treatment of organicwastewater streams using a rotatable bioelectrochemical contactor (RBEC).Bioresour. Technol. 126, 431e436.

Chernicharo, C.A.L., 2007. Anaerobic Reactors. IWA Publishing, London.Christofoletti, C.A., Escher, J.P., Correia, J.E., Marinho, J.F.U., Fontanetti, C.S., 2013. Sug-

arcane vinasse: environmental implications of its use. Waste Manage. 33,2752e2761.

Cibis, E., Kent, C.A., Krzywonos, M., Garncarek, Z., Garncarek, B., Mi�skiewicz, T.,2002. Biodegradation of potato slops from a rural distillery by thermophilicaerobic bacteria. Bioresour. Technol. 85, 57e61.

CONAB, 2013. Acompanhamento da safra brasileira: cana-de-açúcar, quarto levan-tamento, abril/2013. Companhia Nacional de Abastecimento, Brasília. Availableat: <http://www.conab.gov.br/OlalaCMS/uploads/arquivos/13_04_09_10_30_34_boletim_cana_portugues_abril_2013_4o_lev.pdf> (in Portuguese).

Costa, F.J.C.B., Rocha, B.B.M., Viana, C.E., Toledo, A.C., 1986. Utilization of vinasseeffluents from an anaerobic reactor. Water Sci. Technol. 18, 135e141.

Costa, A.C.S., Almeida, V.C.A., Lenzi, E., Nozaki, J., 2002. Determinaç~ao de cobre,alumínio e ferro em solos derivados do basalto atrav�es de extraç~oes seqüenciais.Quim. Nova 25, 548e552 (in Portuguese).

Craveiro, A.M., Soares, H.M., Schmidell, W., 1986. Technical aspects and cost esti-mations for anaerobic systems treating vinasse and brewery/soft drink waste-waters. Water Sci. Technol. 18, 123e134.

Crivelaro, S.H.R., Mariano, A.P., Furlan, L.T., Gonçalves, R.A., Seabra, P.N., Angelis, D.F.,2010. Evaluation of the use of vinasse as a biostimulation agent forthe biodegradation of oily sludge in soil. Braz. Arch. Biol. Technol. 53,1217e1224.

Cruz, F.L.S., 2011. Viabilidade t�ecnica/economica/ambiental das atuais formas deaproveitamento da vinhaça para o setor sucroenerg�etico do Estado de S~aoPaulo. M.Sc. dissertation. University of S~ao Paulo, S~ao Carlos, Brazil (inPortuguese).

Cruz, P.J., Carvalho, F.I.F., Caetano, V.R., Silva, S.A., Kurek, A.J., Marchioro, V.S.,Lorencetti, C., 2000. Efeito do acamamento induzido em trigo. Rev. bras. agro-cien. 6, 112e114 (in Portuguese).

Cruz, J.L., Pelacani, C.R., Coelho, E.F., Caldas, R.C., Almeida, A.Q., Queiroz, J.R., 2006.Influencia da salinidade sobre o crescimento, absorç~ao e distribuiç~ao de s�odio,cloro e macronutrientes em plantulas de maracujazeiro-amarelo. Bragantia 65,275e284 (in Portuguese).

Cruz, J.I., Portugal, R.S., Lucendo, M.C.H., Elis, V.R., Fachin, S.J.S., Ustra, A.T.,Borges, W.R., 2008. Detecç~ao de contaminaç~ao de solo por vinhaça atrav�es dean�alise de dados de eletrorresistividade. Rev. Bras. Geof. 26, 481e492 (inPortuguese).

de Bazúa, C.D., Cabrero, M.A., Poggi, H.M., 1991. Vinasses biological treatment byanaerobic and aerobic processes: laboratory and pilot-plant tests. Bioresour.Technol. 35, 87e93.

Dias, M.O.S., Cunha, M.P., Jesus, C.D.F., Rocha, G.J.M., Pradella, J.G.C., Rossell, C.E.V.,Maciel Filho, R., Bonomi, A., 2011. Second generation ethanol in Brazil: can itcompete with electricity production? Bioresour. Technol. 102, 8964e8971.

Dou�skov�a, I., Ka�st�anek, F., Mal�eterov�a, Y., Ka�st�anek, P., Doucha, J., Zachleder, V., 2010.Utilization of distillery stillage for energy generation and concurrent productionof valuable microalgal biomass in the sequence: biogas-cogeneration-micro-algae-products. Energ. Convers. Manage. 51, 606e611.

Driessen, W., Tielbaard, M.H., Vereijken, T.L.F.M., 1994. Experience on anaerobictreatment of distillery effluent with the UASB process. Water Sci. Technol. 30,193e201.

EIA, 2013. Monthly Energy Review: Renewable Energy e Fuel Ethanol Overview,December/2013. U.S. Energy Information Administration, Washington, DC.Available at: <http://www.eia.gov/totalenergy/data/monthly/pdf/sec10_7.pdf>(last accessed 10.01.14).

Ensinas, A.V., Modesto, M., Nebra, S.A., Serra, L., 2009. Reduction of irreversiblegeneration in sugar and ethanol production from sugarcane. Energy 34,680e688.

Eskicioglu, C., Ghorbani, M., 2011. Effect of inoculum/substrate ratio on mesophilicanaerobic digestion of bioethanol plant whole stillage in batch mode. ProcessBiochem. 46, 1682e1687.

Espa~na-Gamboa, E., Mijangos-Cortes, J., Barahona-Perez, L., Dominguez-Maldonado, J., Hern�andez-Zarate, G., Alzate-Gaviria, L., 2011. Vinasses: charac-terization and treatments. Waste Manage. Res. 29, 1235e1250.

Espinosa, A., Rosas, L., Ilangovan, K., Noyola, A., 1995. Effect of trace metals on theanaerobic degradation of volatile fatty acids in molasses stillage. Water Sci.Technol. 32, 121e129.

Fernandes, B.S., Peixoto, G., Albrecht, F.R., del Aguila, N.K.S., Zaiat, M., 2010. Potentialto produce biohydrogen from various wastewaters. Energy Sustain. Dev. 14,143e148.

Ferreira, L.F.R., Aguiar, M.M., Messias, T.G., Pompeu, G.B., Lopez, A.M.Q., Silva, D.P.,Monteiro, R.T., 2011. Evaluation of sugar-cane vinasse treated with Pleurotussajor-caju utilizing aquatic organisms as toxicological indicators. Ecotox. Envi-ron. Safe 74, 132e137.

Fu, F., Wang, Q., 2011. Removal of heavy metals ions from wastewaters: a review.J. Environ. Manage. 92, 407e418.

Fuess, L.T., 2013. Potencial contaminante e energ�etico da vinhaça: riscos de con-taminaç~ao ao solo e recursos hídricos e recuperaç~ao de energia a partir dadigest~ao anaer�obia. M.Sc. dissertation. S~ao Paulo State University, Rio Claro, SP,Brazil (in Portuguese).

Fuess, L.T., Garcia, M.L., 2013. Qual o valor da vinhaça? Mitigaç~ao de impactoambiental e recuperaç~ao de energia por meio da digest~ao anaer�obia. CulturaAcademica/PROGRAD-Unesp, S~ao Paulo (in Portuguese).

Fuess, L.T., Garcia, M.L., 2014. Anaerobic digestion of stillage to produce bioenergy inthe sugarcane-to-ethanol industry. Environ. Technol. 35, 333e339.

Furlani, A.M.C., Catani, R.A., Moraes, F.R.P., Franco, C.M., 1976. Efeitos da aplicaç~ao decloreto e de sulfato de pot�assio na nutriç~ao do cafeeiro. Bragantia 35, 349e364(in Portuguese).

Gariglio, H.A.A., 2008. Alteraç~oes físicas e químicas e mobilidade de solutos emsolos submetidos �a aplicaç~ao de vinhaça proveniente da fabricaç~ao de �alcoolcarburante. M.Sc. dissertation. Federal University of Viçosa, Viçosa, MG, Brazil(in Portuguese).

Ghosh, M., Ganguli, A., Tripathi, A.K., 2002. Treatment of anaerobically digesteddistillery spentwash in a two-stage bioreactor using Pseudomonas putida andAeromonas sp. Process Biochem. 37, 857e862.

Girardi, F., 2009. Tratamento de vinhaça utilizando coagulantes naturais. M.Sc.dissertation. State University of Maring�a, Maring�a, PR, Brazil (in Portuguese).

Goyal, S.K., Seth, R., Handa, B.K., 1996. Diphasic fixed-film biomethanation of dis-tillery spentwash. Bioresour. Technol. 56, 239e244.

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 227

Gunaseelan, V.N., 1997. Anaerobic digestion of biomass for methane production: areview. Biomass Bioenergy 13, 83e114.

Gunkel, G., Kosmol, J., Sobral, M., Rohn, H., Montenegro, S., Aureliano, J., 2007. Sugarcane industry as a source of water pollution e case study on the situation inIpojuca river, Pernambuco, Brazil. Water Air Soil Pollut. 180, 261e269.

Harada, H., Uemura, S., Chen, A.C., Jayadevan, J., 1996. Anaerobic digestion of arecalcitrant distillery wastewater by a thermophilic UASB reactor. Bioresour.Technol. 55, 215e221.

Hartemink, A.F., 2008. Chapter 3 e sugarcane for bioethanol: soil and environ-mental issues. Adv. Agron. 99, 125e182.

Hati, K.M., Biswas, A.K., Bandyopadhyay, K.K., Misra, A.K., 2007. Soil properties andcrop yields on a vertisol in India with application of distillery effluent. Soil Till.Res. 92, 60e68.

Hill, J., Nelson, E., Tilman, D., Polasky, S., Tiffany, D., 2006. Environmental, economic,and energetic costs and benefits of biodiesel and ethanol biofuels. Proc. Natl.Acad. Sci. U.S.A. 103, 11206e11210.

Huang, X.P., Huang, L.M., Yue, W.Z., 2003. The characteristics of nutrients andeutrophication in the Pearl River estuary, South China. Mar. Pollut. Bull. 47,30e36.

Jain, N., Bhatia, A., Kaushik, R., Kumar, S., Joshi, H.C., Pathak, H., 2005. Impact ofpost-methanation distillery effluent irrigation on groundwater quality. Environ.Monit. Assess. 110, 243e255.

Jiang, Z.P., Li, Y.R., Wei, G.P., Liao, Q., Su, T.M., Meng, Y.C., Zhang, H.Y., Lu, C.Y., 2012.Effect of long-term vinasse application on physico-chemical properties of sug-arcane fields soils. Sugar Tech. 14, 412e417.

Jim�enez, A.M., Borja, R., Martín, A., 2003. Aerobic-anaerobic biodegradation of beetmolasses alcoholic fermentation wastewater. Process Biochem. 38, 1275e1284.

Joshi, G.V., Naik, G.R., 1980. Response of sugarcane to different types of salt stress.Plant Soil 56, 255e263.

Kannan, A., Upreti, R.K., 2008. Influence of distillery effluent on germination andgrowth of mung bean (Vigna radiata) seeds. J. Hazard. Mater. 153, 609e615.

Karhadkar, P.P., Handa, B.K., Khanna, P., 1990. Pilot-scale distillery spentwash bio-methanation. J. Environ. Eng. 116, 1029e1045.

Kaushik, A., Nisha, R., Jagjeeta, K., Kaushik, C.P., 2005. Impact of long and short termirrigation of a sodic soil with distillery effluent in combination with bio-amendments. Bioresour. Technol. 96, 1860e1866.

Kaushik, G., Gopal, M., Thakur, I.S., 2010. Evaluation of performance and communitydynamics of microorganisms during treatment of distillery spent wash in threestage bioreactor. Bioresour. Technol. 101, 4296e4305.

Ke, C., Li, Z., Liang, Y., Tao, W., Du, M., 2013. Impacts of chloride de-icing salt on bulksoils, fungi, and bacterial populations surrounding the plant rhizosphere. Appl.Soil Ecol. 72, 69e78.

Khanal, S.K., 2008. Anaerobic Biotechnology for Bioenergy Production: principlesand applications, first ed. Blackwell Publishing, New Delhi.

Khatiwada, D., Silveira, S., 2011. Greenhouse gas balances of molasses based ethanolin Nepal. J. Clean. Prod. 19, 1471e1485.

Krzywonos, M., Cibis, E., Lasik, M., Nowak, J., Mi�skiewicz, T., 2009. Thermo- andmesophilic aerobic batch biodegradation of high-strength distillery wastewater(potato stillage) e utilisation of main carbon sources. Bioresour. Technol. 100,2507e2514.

Kumar, P., Chandra, R., 2004. Detoxification of distillery effluent through Bacillusthuringiensis (MTCC 4714) enhanced phytoremediation potential of Spirodelapolyrrhiza (L.) Schliden. Bull. Environ. Contam. Toxicol. 73, 903e910.

Kumar, G.S., Gupta, S.K., Singh, G., 2007. Biodegradation of distillery spent wash inanaerobic hybrid reactor. Water Res. 41, 721e730.

Lee, P.H., Bae, J., Kim, J., Chen, W.H., 2011. Mesophilic anaerobic digestion of cornthin stillage: a technical and energetic assessment of the corn-to-ethanol in-dustry integrated with anaerobic digestion. J. Chem. Technol. Biotechnol. 86,1514e1520.

Lepsch, I.F., 2011. 19 liç~oes de pedologia, first ed. Oficina de Textos, S~ao Paulo (inPortuguese).

Levy, G.J., Torrento, J.R., 1995. Clay dispersion and macroaggregate stability asaffected by exchangeable K and sodium. Soil Sci. 160, 352e358.

Liang, G.Z., Wang, Y., Zhou, Y., Liu, H., Wu, Z., 2009. Variables affecting melanoidinsremoval from molasses wastewater by coagulation/flocculation. Sep. Purif.Technol. 68, 382e389.

Liang, G.Z., Wang, Y., Zhou, Y., Liu, H., Wu, Z., 2010. Stoichiometric relationship in thecoagulation of melanoidins-dominated molasses wastewater. Desalination 250,42e48.

Lingle, S.E., Wiegand, C.L., 1997. Soil salinity and sugarcane juice quality. Field Crop.Res. 54, 259e268.

Liu, Z.L., Saha, B.C., Slininger, P.J., 2008. Lignocellulosic biomass conversion toethanol by Saccharomyces. In: Wall, J.D., Harwood, C.S., Demain, A. (Eds.),Bioenergy. ASM Press, Washington DC, pp. 17e36.

Lopes, D.D., Silva, S.M.C.P., Fernandes, F., Teixeira, R.S., Celligoi, A., Dall'Antonia, L.H.,2012. Geophysical technique and groundwater monitoring to detect leachatecontamination in the surrounding area of a landfill e Londrina (PR-Brazil).J. Environ. Manage. 113, 481e487.

Luo, G., Xie, L., Zhou, Q., 2009. Enhanced treatment efficiency of an anaerobicsequencing batch reactor (ASBR) for cassava stillage with high solids content.J. Biosci. Bioeng. 107, 641e645.

Luo, G., Xie, L., Zou, Z., Wang, W., Zhou, Q., Shim, H., 2010. Anaerobic treatment ofcassava stillage for hydrogen and methane production in continuously stirredtank reactor (CSTR) under high organic loading rate (OLR). Int. J. HydrogenEnergy 35, 11733e11737.

Luo, G., Xie, L., Zhou, Q., Angelidaki, I., 2011. Enhancement of bioenergy productionfrom organic wastes by two-stage anaerobic hydrogen and methane productionprocess. Bioresour. Technol. 102, 8700e8706.

Lutoslawski, K., Ryznar-Luty, A., Cibis, E., Krzywonos, M., Mi�skiewicz, T., 2011.Biodegradation of beet molasses vinasse by a mixed culture of micro organisms:effect of aeration conditions and pH control. J. Environ. Sci. 23, 1823e1830.

Lyra, M.R.C.C., Roli, M.M.M., Silva, J.A.A., 2003. Toposeqüencia de solos fertigadoscom vinhaça: contribuiç~ao para a qualidade das �aguas do lençol fre�atico. Rev.bras. eng. agríc. ambient. 7, 525e532 (in Portuguese).

Macedo, I.C., 2005. A energia da cana-de-açúcar: doze estudos sobre a agroindústriada cana-de-açúcar no Brasil e a sustentabilidade, second ed. Berlendis & Ver-tecchia/UNICA, S~ao Paulo.

Macedo, I.C., Seabra, J.E.A., Silva, J.E.A.R., 2008. Green house gases emissions in theproduction and use of ethanol from sugarcane in Brazil: the 2005/2006 aver-ages and a prediction for 2020. Biomass Bioenergy 32, 582e595.

Madej�on, E., L�opez, R., Murillo, J.M., Cabrera, F., 2001. Agricultural use of three(sugar-beet) vinasse composts: effect on crops and chemical properties of aCambisol soil in the Guadalquivir river valley (SW Spain). Agric. Ecosyst. En-viron. 84, 55e65.

Majerus, V., Bertin, P., Lutts, S., 2007. Effects of iron toxicity on osmotic potential,osmolytes and polyamines concentrations in the African rice (Oryza glaberrinaSteud.). Plant Sci. 173, 96e105.

Mariano, A.P., Crivelaro, S.H.R., Angelis, D.F., Bonotto, D.M., 2009. The use of vinasseas an amendment to ex-situ bioremediation of soil and groundwater contam-inated with diesel oil. Braz. Arch. Biol. Technol. 52, 1043e1055.

McCarty, P.L., Bae, J., Kim, J., 2011. Domestic wastewater treatments as a net energyproducer e can this be achieved? Environ. Sci. Technol. 45, 7100e7106.

Megda, M.X.V., Mariano, E., Leite, J.M., Megda, M.M., Trivelin, P.C.O., 2014. Chlorideion as nitrification inhibitor and its biocidal potential in soil. Soil Biol. Biochem.72, 84e87.

Metcalf & Eddy, Inc., 2003. Wastewater Engineering: Treatment and Reuse, fourthed. McGraw-Hill, Inc., New York.

Miranda, T.L., Pedrosa, E.M.R., Silva, E.F.F., Rolim, M.M., 2012. Alteraç~oes físicas ebiol�ogicas em solo cultivado com cana-de-açúcar ap�os colheita e aplicaç~ao devinhaça. Agr�aria 7, 150e158 (in Portuguese).

Mohan, K.K., Vaidya, R.N., Reed, M.G., Fogler, H.S., 1993. Water sensitivity of sand-stones containing swelling and non-swelling clays. Colloid. Surf. A 73, 237e254.

Mohana, S., Acharya, B.K., Madamwar, D., 2009. Distillery spent wash: treatmenttechnologies and potential applications. J. Hazard. Mater. 163, 12e25.

Montes-H, G., Duplay, J., Martinez, L., Geraud, Y., Rousset-Tournier, B., 2003. Influ-ence of interlayer cations on the water sorption and swelling-shrinkage ofMX80 bentonite. Appl. Clay Sci. 23, 309e321.

Moraes, B.S., Junqueira, T.L., Pavanello, L.G., Cavalett, O., Mantelatto, P.E., Bonomi, A.,Zaiat, M., 2014. Anaerobic digestion of vinasse from sugarcane biorefineries inBrazil from energy, environmental, and economic perspectives: profit orexpense? Appl. Energy 113, 825e835.

Moreira, C.A., Braga, A.C.O., 2009. Decomposiç~ao de resíduos s�olidos domiciliares evariaç~oes na resistividade e cargabilidade. Rev. Bras. Geofis. 27, 401e409 (inPortuguese).

Moura, H.P., Malagutti Filho, W., 2007. M�etodos da eletrorresistividade e da polar-izaç~ao induzida aplicados no estudo do aterro controlado de Piracicaba-SP.Geociencias 26, 35e43 (in Portuguese).

Murphy, J.D., Power, N.M., 2008. How canwe improve the energy balance of ethanolproduction from wheat? Fuel 87, 1799e1806.

Nandan, R., Tondwalkar, V., Ray, P.K., 1990. Biomethanation of spent wash: heavymetal inhibition of methanogenesis in synthetic m�edium. J. Ferment. Bioeng.69, 276e282.

Nandy, T., Shastry, S., Kaul, S.N., 2002. Wastewater management in a cane molassesdistillery involving bioresource recovery. J. Environ. Manage. 65, 25e38.

Nasr, N., Elbeshbishy, E., Hafez, H., Nakhla, G., Hesham, M., El Naggar, M.H., 2011.Bio-hydrogen production from thin stillage using conventional and acclima-tized anaerobic digester sludge. Int. J. Hydrogen Energy 36, 12761e12769.

Ni, J.Q., Naveau, H., Nyns, E.J., 1993. Biogas: exploitation of a renewable energy inLatin America. Renew. Energy 3, 763e779.

Nichols, N.N., Monceaux, D.A., Dien, B.S., Bothast, R.J., 2008. Production of ethanolfrom corn and sugarcane. In: Wall, J.D., Harwood, C.S., Demain, A. (Eds.), Bio-energy. ASM Press, Washington DC, pp. 3e15.

Nudel, B.C., Waehner, R.S., Fraile, E.R., Giulietti, A.M., 1987. The use of single andmixed cultures for aerobic treatment of cane sugar stillage and SCO production.Biol. Waste 22, 67e73.

Olguín, E.J., S�anchez-Galv�an, G., Gonz�alez-Portela, R.E., L�opez-Vela, M., 2008. Con-structed wetland mesocosms for the treatment of diluted sugarcane molassesstillage from ethanol production using Pontederia sagittata. Water Res. 42,3659e3666.

Oliveira, B.G., Carvalho, J.L.N., Cerri, C.E.P., Cerri, C.C., Feigl, B.J., 2013. Soil greenhosegas fluxes from vinasse application in Brazilian sugarcane �areas. Geoderma200e201, 77e84.

Pandey, R.A., Malhotra, S., Tankhiwale, A., Pande, S., Pathe, P.P., Kaul, S.N., 2003.Treatment of biologically treated distillery effluent e a case study. Int. J. Envi-ron. Stud. 60, 263e275.

Pant, D., Adholeya, A., 2007. Biological approaches for treatment of distillerywastewater: a review. Bioresour. Technol. 98, 2321e2334.

Park, S.E., Robertson, M., Inman-Bamber, N.G., 2005. Decline in the growth of asugarcane crop with age under high input conditions. Field Crop Res. 92,305e320.

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229228

Parnaudeau, V., Condom, N., Oliver, R., Cazevieille, P., Recous, 2008. Vinasse organicmatter quality and mineralization potential, as influenced by raw material,fermentation and concentration processes. Bioresour. Technol. 99, 1553e1562.

Pathak, H., Joshi, H.C., Chaudhary, A., Chaudhary, R., Kalra, N., Dwiwedi, M.K., 1999.Soil amendment with distillery effluent for wheat and rice cultivation. WaterAir Soil Pollut. 133, 133e140.

Petruzzelli, G., 1989. Recycling wastes in agriculture: heavy metal bioavailability.J. Environ. Manage. 27, 493e503.

Piedras, S.R.N., Oliveira, J.L.R., Moraes, P.R.R., Bager, A., 2006. Toxicidade aguda daammonia n~ao ionizada e do nitrito em alevinos de Cichlasoma facetum(JENYNS, 1842). Cienc. Agrotec. 30, 1008e1012.

Pimentel, D., Patzek, T.W., Cecil, G., 2007. Ethanol production: energy, economic,and environmental losses. Rev. Environ. Contam. Toxicol. 189, 25e41.

Podg�orska-Lesiak, M., Sobkowicz, P., 2013. Prevention of pea lodging by inter-cropping barley with peas at different nitrogen fertilization levels. Field CropRes. 149, 95e104.

Prada, S.M., Guekezian, M., Su�arez-Iha, M.E.V., 1998. Metodologia analítica para adeterminaç~ao de sulfato em vinhoto. Quim. Nova 21, 249e252 (in Portuguese).

Prasad, K.R., 2009. Color removal from distillery spent wash through coagulationusing Moringa oleífera seeds: use of optimum response surface methodology.J. Hazard. Mater. 165, 804e811.

Previna, S., Saravanan, A.D., 2013. Ecofriendly utilization of treated distilleryefluente (TDE) and inorganic fertilizers management on microbial populationand enzymatic activities. IJSRP 3, 1e6.

Ramalho, J.F.G.P., Amaral Sobrinho, N.M.B., 2001. Metais pesados em solos culti-vados com cana-de-açúcar pelo uso de resíduos agroindustriais. FlorestaAmbient. 8, 120e129.

Ramana, S., Biswas, A.K., Kundu, S., Saha, J.K., Yadava, R.B.R., 2002. Effect of distilleryeffluent on seed germination in some vegetable crops. Bioresour. Technol. 82,273e275.

Reali, M.A.P., Paz, L.P.S., Daniel, L.A., 2013. Tratamento de �agua para consumohumano. In: Calijuri, M.C., Cunha, D.G.F. (Eds.), Engenharia ambiental: con-ceitos, tecnologia e gest~ao. Elsevier, Rio de Janeiro, pp. 405e453 (inPortuguese).

Renault, P., Cazevieille, P., Verdier, J., Lahlah, J., Clara, C., Favre, F., 2009. Variations inthe cation exchange capacity of a ferralsol supplied with vinasse, underchanging aeration conditions. Geoderma 154, 101e110.

Ribas, M.M.F., 2006. Tratamento de vinhaça em reator anaer�obio operado embatelada seqüencial contendo biomassa imobilizada sob condiç~oes termofílicase mesofílicas. Ph.D. thesis. University of S~ao Paulo, S~ao Carlos, SP, Brazil.

Ribeiro, B.T., Lima, J.M., Guilherme, L.R.G., Juli~ao, L.G.F., 2010. Lead sorption andleaching from an Inceptisol sample amended with sugarcane vinasse. Sci. Agric.67, 441e447.

Richards, L.A. (Ed.), 1954. Diagnosis and Improvement of Saline and Alkali Soils, firsted. USDA, Washington.

Robbins, C.W., 1984. Sodium adsorption ratio-exchangeable sodium percentagerelationship in a high potassium saline-sodic soil. Irrigat. Sci. 5, 173e179.

Robles-Gonz�alez, V., Galíndez-Mayer, J., Rinderknecht-Seijas, N., Poggi-Varaldo, H.M.,2012. Treatment of mezcal vinasses: a review. J. Biotechnol. 157, 525e546.

Rodrigues, I.J., Fuess, L.T., Biondo, L., Santesso, C.A., Garcia, M.L., 2013. Coagulation-flocculation of anaerobically treated sugarcane stillage. Desalin. Water Treat.http://dx.doi.org/10.1080/19443994.2013.801785.

Rolim, M.M., Lyra, M.R.C.C., Duarte, A.S., Medeiros, P.R.F., França e Silva, E.F.,Pedrosa, E.M.R., 2013. Influencia de uma lagoa de distribuiç~ao de vinhaça naqualidade da �agua fre�atica. Rev. Ambient. �Agua 8, 155e171 (in Portuguese).

Russo, C., Sant'Anna Jr., G.L., Pereira, S.E.C., 1985. An anaerobic filter applied to thetreatment of distillery wastewaters. Agr. Waste. 14, 301e313.

Ryan, D., Gadd, A., Kavanagh, J., Zhou, M., Barton, G., 2008. A comparison of coag-ulant dosing options for the remediation of molasses process water. Sep. Purif.Technol. 58, 347e352.

S�anchez Riera, F., Valz-Gianinet, S., Callieri, D., Si~neriz, F., 1982. Use of a packed-bedreactor for anaerobic treatment of stillage of sugar cane molasses. Biotechnol.Lett. 4, 127e132.

S�anchez Riera, F., Cordoba, P., Si~neriz, F., 1985. Use of the UASB reactor for theanaerobic treatment of stillage from sugar cane molasses. Biotechnol. Bioeng.27, 1710e1716.

Sangave, P.C., Pandit, A.B., 2004. Ultrasound pre-treatment for enhanced biode-gradability of the distillery wastewater. Ultrason. Sonochem. 11, 197e203.

Sangave, P.C., Pandit, A.B., 2006. Ultrasound and enzyme assisted biodegradation ofdistillery wastewater. J. Environ. Manage. 80, 36e46.

Sangave, P.C., Gogate, P.R., Pandit, A.B., 2007. Combination of ozonation with con-ventional aerobic oxidation for distillery wastewater treatment. Chemosphere68, 32e41.

Santana, V.S., Machado, N.R.C.F., 2008. Photocatalytic degradation of the vinasseunder solar radiation. Catal. Today 133, 606e610.

Santana, M.J., Carvalho, J.A., Souza, K.J., Souza, A.M.G., Vasconcelos, C.L.,Andrade, L.A.B., 2007. Efeitos da salinidade da �agua de irrigaç~ao na brotaç~ao edesenvolvimento inicial da cana-de-açúcar (Saccharum spp) e em solos comdiferentes níveis texturais. Cienc. Agrotec. 31, 1470e1476 (in Portuguese).

Santos, J.D., Silva, A.L.L., Cosata, J.L., Scheidt, G.N., Novak, A.C., Sydney, E.B.,Soccol, C.R., 2013. Development of a vinasse nutritive solution for hydroponics.J. Environ. Manage. 114, 8e12.

S~ao Paulo, 1976. Decreto n. 8468, de 08 de setembro de 1976. Aprova o Regulamentoda Lei n. 997, de 31 de maio de 1976, que disp~oe sobre a prevenç~ao e controle dapoluiç~ao do meio ambiente.

Satyawali, Y., Balakrishnan, M., 2008. Wastewater treatment in molasses-basedalcohol distilleries for COD and color removal: a review. J. Environ. Manage.86, 481e497.

Schaefer, S.H., Sung, S., 2008. Retooling the ethanol industry: thermophilic anaer-obic digestion of thin stillage for methane production and pollution prevention.Water Environ. Res. 80, 101e108.

Seth, R., Goyal, S.K., Handa, B.K., 1995. Fixed film biomethanation of distilleryspentwash using low cost porous media. Resour. Conserv. Recyc. 14, 79e89.

Sheehan, G.J., Greenfield, P.F., 1980. Utilisation, treatment and disposal of distillerywastewater. Water Res. 14, 257e277.

Shivayogimath, C.B., Ramanujam, T.K., 1999. Treatment of distillery spentwash byhybrid UASB reactor. Bioprocess Eng. 21, 255e259.

Shrihari, S., Tare, V., 1989. Anaerobic-aerobic treatment of distillery wastes. WaterAir Soil Pollut. 43, 95e108.

Siles, J.A., García-García, I., Martín, A., Martín, M.A., 2011. Integrated ozonation andbiomethanization treatments of vinasse derived from ethanol manufacturing.J. Hazard. Mater. 188, 247e253.

Silva, W.P., Almeida, C.D.G.C., Rolim, M.M., Silva, E.F.F., Pedrosa, E.M.R., Silva, V.G.F.,2014. Monitoramento da salinidade de �aguas subterraneas em v�arzea cultivadacom cana-de-açúcar fertirrigada com vinhaça. Rev. bras. eng. agríc. ambient 18,394e401.

Singh, S.S., Dikshit, A.K., 2010. Optimization of the parameters for decolourizationby Aspergillus niger of anaerobically digested distillery spentwash pretreatedwith polyaluminium chloride. J. Hazard. Mater. 176, 864e869.

Singh, N.K., Pandey, G.C., Rai, U.N., Tripathi, R.D., Singh, H.B., Gupta, D.K., 2005.Metal accumulation and ecophysiological effects of distillery effluent on Pota-mogeton pectinatus L. Bull. Environ. Contam. Toxicol. 74, 857e863.

Sivaloganathan, P., Murugaiyan, B., Appavou, S., Dharmaraj, L., 2013. Effect of dilu-tion of treated distillery effluent (TDE) on soil properties and yield of sugarcane.Am. J. Plant Sci. 4, 1811e1814.

Smeets, E., Junginger, M., Faaij, A., Walter, A., Dolzan, P., Turkenburg, W., 2008. Thesustainability of Brazilian ethanol: an assessment of the possibilities of certifiedproduction. Biomass Bioenergy 32, 781e813.

Sohsalam, P., Sirianuntapiboon, S., 2008. Feasibility of using constructed wetlandtreatment for molasses wastewater treatment. Bioresour. Technol. 99,5610e5616.

Souza, R.P., 2010. Reduç~ao da toxicidade da vinhaça: tratamento combinado coag-ulaç~ao/floculaç~ao/fotocat�alise. M.Sc. dissertation. State University of Maring�a,Maring�a, PR, Brazil (in Portuguese).

Souza, M.E., Fuzaro, G., Polegato, A.R., 1992. Thermophilic anaerobic digestion ofvinasse in pilot plant UASB reactor. Water Sci. Technol. 25, 213e222.

Stover, E.L., Gomathinayagam, G., Gonzalez, R., 1984. Use of methane gas fromanaerobic treatment of stillage for fuel alcohol production. In: Proceedings ofthe 39th Industrial Waste Conference. West Lafayette, May. 8e10, PurdueUniversity, Boston Butterworth, pp. 57e63.

Strong, P.J., Burgess, J.E., 2008. Treatment methods for wine-related and distillerywastewaters: a review. Biorem. J. 12, 70e87.

Syaichurrozi, I., Budiyono, Sumardiono, S., 2013. Predicting kinetic model of biogasproduction and biodegradability organic materials: biogas production fromvinasse at variation of COD/N ratio. Bioresour. Technol. 149, 390e397.

Tasso Jr., L.G., Marques, M.O., Franco, A., Nogueira, G.A., Nobile, F.O., Camilotti, F.,Silva, A.R., 2007. Produtividade e qualidade de cana-de-açúcar cultivada em solotratado com lodo de esgoto, vinhaça e adubos minerais. Eng. Agríc. 27, 276e283.

Tejada, M., Gonzalez, J.L., 2005. Beet vinasse applied to wheat under dryland con-ditions affects soil properties and yield. Eur. J. Agron. 23, 336e347.

Tejada, M., Gonzalez, J.L., 2006. Effects on two beet vinasse forms on soil physicalproperties and soil loss. Catena 68, 41e50.

Tejada, M., Moreno, J.L., Hernandez, M.T., Garcia, C., 2007. Application of two beetvinasse forms in soil restoration: effects on soil properties in an arid environ-ment in southern Spain. Agric. Ecosyst. Environ. 119, 289e298.

Tondee, T., Sirianuntapiboon, S., Ohmono, S., 2008. Decolorization of molasseswastewater by yeast strain, Issatchenkia orientalis No. SF9-246. Bioresour.Technol. 99, 5511e5519.

USEPA, 1986. Multimedia Technical Support Document for the Ethanol-for-fuelIndustry. EPA 440/1-86/093. U.S. Environmental Protection Agency, Washing-ton, DC.

USEPA, 2004. 2004 Guidelines for Water Reuse. EPA 625/R-04/108. U.S. Environ-mental Protection Agency, Cincinnati.

Valderrama, L.T., Del Campo, C.M., Rodriguez, C.M., de-Bashan, L.E., Bashan, Y., 2002.Treatment of recalcitrant wastewater from ethanol and citric acid productionusing microalga Chlorella vulgaris and the macrophyte Lemna minuscule.Water Res. 36, 4185e4192.

Vlissidis, A., Zouboulis, A.I., 1993. Thermophilic anaerobic digestion of alcohol dis-tillery wastewaters. Bioresour. Technol. 43, 131e140.

von Sperling, M., 2007. Wastewater Characteristics, Treatment and Disposal. IWAPublishin, London.

Wahid, A., Rao, A.R., Rasul, E., 1997. Identification of salt tolerance traits in sugar-cane lines. Field Crop Res. 54, 9e17.

Watkins, C.H., Hammerschlag, R.S., 1984. The toxicity of chlorine to a commonvascular aquatic plant. Water Res. 18, 1037e1043.

WHO, 2006. Guidelines for the Safe Use of Wastewater, Excreta and Greywater.World Health Organization, Geneva.

Wiegand, C., Anderson, G., Lingle, S., Escobar, D., 1996. Soil salinity effects on cropgrowth and yield e illustration of an analysis and mapping methodology forsugarcane. J. Plant Physiol. 148, 418e424.

L.T. Fuess, M.L. Garcia / Journal of Environmental Management 145 (2014) 210e229 229

Wiegant, W.M., Claassen, J.A., Lettinga, G., 1985. Thermophilic anaerobic digestionof high strength wastewaters. Biotechnol. Bioeng. 27, 1374e1381.

Wilkie, A.C., 2008. Biomethane from biomass, biowaste and biofuels. In: Wall, J.D.,Harwood, C.S., Demain, A. (Eds.), Bioenergy. ASM Press, Washington DC,pp. 195e205.

Wilkie, A.C., Riedesel, K.J., Owens, J.M., 2000. Stillage characterization and anaerobictreatment of ethanol stillage from conventional and cellulosic feedstocks.Biomass Bioenergy 19, 63e102.

Wilkinson, A., 2011. Anaerobic Digestion of Corn Ethanol Thin Stillage for BiogasProduction in Batch and by Down-flow Fixed Film Reactor. M.Sc. dissertation.University of Ottawa, Ottawa, Canada.

Willington, I.P., Marten, G.G., 1982. Options for handling stillage waste from sugar-based fuel ethanol production. Resour. Conserv. 8, 111e129.

Withers, P.J.A., Jarvie, H.P., Stoate, C., 2011. Quantifying the impact of septic tanksystems on eutrophication risk in rural headwaters. Environ. Int. 37, 644e653.

Xing, G.X., Zhang, S.F., Ju, B.Z., Yang, J.Z., 2005. Recent advances in modified starch asflocculant. In: The Proceedings of the Third International Conference on Func-tional Molecules, Dalian, pp. 13e18.

Yavuz, Y., 2007. EC and EF processes for the treatment of alcohol distillery waste-water. Sep. Purif. Technol. 53, 135e140.

Yen, H.W., Yang, Y.C., Yu, Y.H., 2012. Using crude glycerol and thin stillage for theproduction of microbial lipids through the cultivation of Rhodotorula glutinis.J. Biosci. Bioeng. 114, 453e456.

Yeoh, B.G., 1997. Two-phase anaerobic treatment of cane-molasses alcohol stillage.Water Sci. Technol. 6, 441e448.

Yruela, I., 2005. Copper in plants. Braz. J. Plant. Physiol. 17, 145e156.Zayas, T., Romero, V., Meraz, M., Salgado, L., 2006. Tratamiento de agua residual con

alta carga org�anica y color provenientes del processo de vinaza. In: Memoriasdel 5º Congresso Internacional y 11º Nacional de Ciencias Ambientales, UAEM,Oaxtepec Morelos, pp. 1e7 (in Spanish).

Zayas, T., Romero, V., Salgado, L., Meraz, M., Morales, U., 2007. Applicability ofcoagulation/flocculation and electrochemical processes to the purification ofbiologically treated vinasse effluent. Sep. Purif. Technol. 57, 270e276.

Zhang, J., Li, G., Song, Y., Liu, Z., Yang, C., Tang, S., Zheng, C., Wang, S., Ding, Y., 2014.Lodging resistance characteristics of high-yielding rice populations. Field CropRes. 161, 64e74.

Zolim, C.A., Paulino, J., Bertonha, A., Freitas, P.S.L., Folegatti, M.V., 2011. Estudoexplorat�orio do uso da vinhaça ao longo do tempo. I. Características do solo.Rev. bras. eng. agríc. ambient. 15, 22e28.