COMPREHENSIVE INDUSTRY DOCUMENTSERIES: COINDS/62/2006-07

ComprehensiveIndustry

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PROCESSINGINDUSTRY

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CENTRAL POLLUTION CONTROL BOARDMINISTRY OF ENVIRONMENT & FORESTS

e-mail : cpcb(a alpha.nic.in Website : www.cpcb.nicia

April 2006

COMPREHENSIVE INDUSTRY DOCUMENTSERIES: COINDS/62/2006-07

COMPREHENSIVE INDUSTRY DOCUMENTON

COFFEE PROCESSING INDUSTRY

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°p CLEAN 0

CENTRAL POLLUTION CONTROL BOARD(Ministry of Environment & Forests, Govt. of India)

Parivesh Bhawan, East Arjun NagarDelhi-110032

Website : www.cpcb.nic.in e-mail : cpcb@nic.in

CPCB 200 Copies, 2006

Published By: Dr. B. Sengupta, Member Secretary, Central Pollution Control Board, Delhi - 32Printing Supervision & Layout: P.K. Mahendru and Mrs. Anamika SagarComposing & Laser Typesetting : Mohd. JavedPrinted at: National Institute of Science Communication and Information Resources, CSIR,

Dr. K.S. Krishnan Marg, New Delhi

FOREWORD

Central Pollution Control Board (CPCB) has conducted in-depth studies in selected coffeeprocessing units to assess the performance of pollution control facilities adopted by theunits.

The basic document in coffee processing industries was prepared by ENC ConsultingEngineers. Sh. H.K.Karforma, SEE and Sh. S.K. Gupta, EE have co-ordinated projectactivities and prepared the present report under the guidance of Dr. B. Sengupta,Member Secretary and Sh. P.M. Ansari, Additional Director of Central Pollution ControlBoard.

The help and assistance rendered by Tata Coffee Estate, Hindustan Lever Limited,Coffee Board and KSPCB in preparing the report is gratefully acknowledged. Ms. Himajwala, JRF and Sh Narain Singh provided the secretarial assistance.

I trust the document will be useful to all those interested in pollution control in wet coffeeplantations and instant coffee manufacturing processes.

(Dr. V. RAJAGOPALAN)Chairman, CPCB

CONTENTS

Page No.

1.0 SUMMARY 12.0 Introduction & Objective 3

2.1 Introduction 3

2.2 Objective 3

3.0 Coffee Cultivation & Production in India 5

3.1 Statewise Distribution of Coffee Cultivation 53.2 Propagation of Coffee 63.3 Water Requirement/ Irrigation Practices 73.4 Uses of Fertilizers 73.5 Effect of Fertilizers Use on Water Quality 83.6 Diseases of Coffee Plant & Use of Pesticides and Fungicides 9

4.0 Environmental Effects of Pesticides/ Fungicides used in CoffeePlantation 12

4.1 General

124.2 Major Pesticides/ Fungicides

13

4.3 Overall Conclusion

16

5.0 Processing of Coffee 17

5.1 General 175.2 Preparation of Parchment Coffee 175.3 Preparation of Cherry Coffee 195.4 Curing Works 195.5 Instant Coffee 195.6 Selection of Units for in-depth Studies 20

6.0 In-depth Studies in Selected Coffee Processing Industry andCoffee Plantation Estates 22

6.1 General 226.2 Manufacturing Process 226.3 Material, Energy & Water Balance 236.4 Genesis of Pollution and Identification of Pollutants 246.4.1 Water Pollution & Wastewater Treatment 246.4.2 Air Pollution & its control 286.4.3 Noise Pollution 296.4.4 Solid Waste Management 29

7.0 Coffee Curing Unit : Mysore Coffee Curing Works atChikmagalur, Karnataka 32

7.1 General 327.2 Manufacturing Process 327.3 Genesis of Pollution and Identification of Pollutants 337.4 Material & Energy Balance 337.5 Waste Management Practices 34

8.0 In-depth Study in Large Coffee Plantations 35

8.1 Tata Coffee Ltd., Nullore Division, Distt. Kodagu 358.2 Tata Coffee Ltd., Hope Division - Woshally Estate 368.3 Consolidated Coffee Ltd., Karadibetta Estate, Rayarakoppalu

Distt. Hassan, 378.4 Conclusion 39

9.0 Pollution Control in Coffee Processing 40

9.1 Instant Coffee Manufacturing Plant 409.1.1 Wastewater Treatment practices 409.1.2 Air Pollution and its control 429.2 Coffee Plantation — Wet Processing 439.2.1 Wastewater Treatment Method 439.2.2 Wastewater Treatment Methods used in Other Countries 449.3 Pollution issues and its control in Coffee Curing Works 459.4 Suggested Method of Treatment of Wastewater 459.4.1 Treatment Objectives 47

10.0 Proposed Standards for Coffee Processing Industries 61

10.1 General 6110.2 Instant Coffee Industry 6110.3 Coffee Curing Works 6110.4 Coffee Plantations - Wet Processing 61

1.0 SUMMARY

1. Coffee is manufactured in the states of Karnataka (71%) and Tamil Nadu (8%). Themaximum production of Coffee comes from the state of Karnataka. Robusta and Arabicare the two major varieties of coffee manufactured in the country.

2. 98% of the coffee growers have small holdings less than 10 ha. And uses 3,000 lit, ofwater per day. Medium and large scale holdings have 10-25 ha. And 25 ha. And abovearea under coffee plantation respectively.

3. Coffee is manufactured by dry process (instant coffee/cherry fruit) and wet processing(parchment coffee)

4. Cherry coffee is manufactured by the use of ripen coffee fruits and is dried naturally.There is no waste generation from this process while in instant coffee manufacturingcoffee beans are cleaned, roasted and grounded. The grounded coffee is extracted withhot water followed by evaporation and drying of filtrate having soluble coffee tomanufacture coffee powder. Wastewater is generated mostly from the spent coffee waste.

5.

The manufacturing of parchment coffee is by using wet process which includes pulpingof fruits, its mucilization followed by its drying.

Environmental aspects in Coffee processing industry:

1. Instant Coffee industry:

1.1 Wastewater generation and its treatmentIn instant coffee manufacturing, wastewater is generated from spent coffee waste. Thewastewater is acidic in nature and has BOD:600-1000 mg/1, COD: 2500-10,000 mg/l, SS:100-1000 mg/1. The wastewater generation is about 300 kld which is generally 50-55% ofwater use.

Activated sludge process is generally used for treatment of wastewater followed byphysico-chemical treatment for colour removal. Such treatment process has resulted inBOD- 10 mg/l, COD — 93 mg/l and SS — 14 mg/l.

1.2 Air pollutionAir pollution is mainly caused by hot air generation (by Diesel burning), cleaning ofbeans, D.G.sets and boilers. For air pollution control cyclones/ bag filters have beenprovided and results are within the specified limit. For control of odour nuisance, VOC'scontaining coffee aroma are taken care of by catalytic converters.

1.3 Solid wasteMain source of solid waste is spent coffee waste which is sent to boiler as a fuel

2. Wet processing industry (Parchment coffee):

2.1 Wastewater generation and its treatmentThe main sources of wastewater generation are pulper and washer. About 80-100 cum/tonne of water is used for cleaning of coffee. The effluent generated is acidic in nature

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and has BOD ranges from 2500-12,000 mg/l. While in case of aqua pulper where water isrecycled, the BOD may go upto 30,000 mg/l.

The treatment of wastewater is done by (i) Anaerobic — Aerobic, (ii) By enzymetreatment.

The conventional treatment options employed could not yield the treatment results (BOD— 5700 mg/l, COD — 10, 6405 mg/l, SS — 462 mg/1). It may be due to improper operationand inadequate size of units. The enzyme treatments have produced very good quality ofeffluents having BOD —5 mg/l, COD — 56 mg/l, SS — 14 mg/l.

3. Coffee curing works:The entire process of coffee curing is dry with no water pollution while air pollutioncaused by DG sets. The solid waste produced in husk which is reused in anyway.

Treatment options suggested for wastewater:

Following treatment options suggested for treatment of wastewater and to achieve the dischargestandards:

1. To bring down BOD level below 500 mg/l by using conventional biological treatmentmethods.

2. To adopt suitable technology for tertiary treatment (Physico-chemical) to bring downBOD level below 100 mg/l.

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2.0 INTRODUCTION & OBJECTIVE

2.1 Introduction

India is one of the major producers of Coffee in world. In India, two major varieties of coffee arecultivated on commercial scale:

- Arabica- Robusta

Generally, coffee is grown in hilly regions (western ghat areas) of Karnataka, Kerala, TamilNadu, and some part of Andhra Pradesh & Northeastern region. Arabica is grown in higherelevation, while Robusta in relatively lower elevation.

Coffee is a flowering plant with white fragrant flowers (Photo 1). It is a shade loving plant(Seiphyte) growing mostly on laterite soil with well-distributed rainfall (Photo 2). Coffee beans,after processing & curing, may be roasted & grounded to make a coffee powder and may be usedas filter coffee. Powdered coffee may be further processed as Instant Coffee, which now a days isfrequently used in India. In India Central Coffee Research Institute (CCRI) at Chikamagalur(Karnataka) is engaged in carrying out extensive research on coffee.

2.2 Objective

As there was no comprehensive national document available on environmental issues related toCoffee processing industry and therefore, Central Pollution Control Board has taken-up theproject to carry-out in-depth studies in selected coffee fields and coffee processing industries.The document consist of information about raw materials, processes, pollution aspect, PollutionControl Practices (PCP) and proposed National Standard for the industry, keeping in view theBest Available Technology (BAT), sustenance & applicability under the prevailing conditions.

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Photo I: Coffee Plant with Flowers

Photo 2 : Coffee Plants in Shade

3.0 COFFEE CULTIVATION & PRODUCTION IN INDIA

3.1 Statewise Distribution of Coffee Cultivation

Coffee is mainly grown in Karnataka, Kerala, Tamil Nadu & some parts of Andhra Pradesh,Orissa & North-eastern regions. Land holders which have land upto 4 ha are called as small landholders, 4-10 ha called as medium land holders and those holding more than 10 ha are termed aslarge holders. The number of estates (holding) are given in Table 3.1.

Table 3.1 Distribution of Holding under Coffee(1994-95)

No. of estatesStates Total<4ha % 4-10 ha % >10ha %

Karnataka 33,689 84.85 4,160 10.48 1,855 4.67 39,704Kerala 74,240 97.18 1,676 2.20 477 0.62 76,393

Tamil Nadu 12,642 92.52 728 5.33 294 2.15 13,664Others

(A.P.,Orissa,Maharastra 10,508 99.77 -- -- 24 0.23 10,532

& NEregions)

Grand Total 131,079 93.43 6,564 4.68 2,650 1.89 140,293

Table 3.1 shows that small growers (less than 4 ha) account for more than 93% of area undercoffee while only 1.9% account for large states of more than 10 ha. Number of estates in the 4-10ha range constitute 4.68% of total. The table also shows that member of small holding is highestin Kerala, while medium & large holdings are highest in Karnataka. The coffee estates in Keralaand Tamil Nadu are generally small holdings (97.2% and 92.5%) respectively.

The statewise planted area of coffee (1995-96) in various states of India has been furnished inTable 3.2.

Table 3.2 Statewise planted area of Coffee in India (1995-96) in (ha)

States Arabica % Robusta % Total %Karnataka 96,379 57 72,702 43 169,081 55.41Kerala 4,166 5 78,182 95 82,348 26.98Tamil Nadu 27,270 83 5,508 17 32,778 10.74Others 18,086 86 2,860 14 20,946 6.87Total 145,901 48 159,252 52 305,153 100.00

From the above table it is clear that planted area under coffee is highest in Karnataka(55.41 %) ascompared to the total planted area in India.

Karnataka contributes about 71% of total coffee production, Kerala (21%) & Tamil Nadu (M).The statewise status of coffee production is given in Table 3.3.

In Karnataka, main coffee producing districts are Chikmagalur, Hassan and Kodagu.

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Table 3.3 Statewise production of Coffee in India (1997-98) in Tones

States Arabica %* Robusta %* Total I %+Karnataka 83,700 52 78,400 48 162,100 69.7

Kerala 1,900 4 49,000 96 50,900 22.0Tamil Nadu 13,000 76 4,000 24 17,000 7.5

Others 2,000 100 -- -- 2,000 0.8Total 10,600 43 131,400 57 232,000 100.0

Note:* of state's total+ of India's total

3.2 Propagation of Coffee

(i) General

Arabica and Robusta can be propagated by seed as well as by clonal means. By seedpropagation, high degree of uniformity could be achieved in Arabica Coffee. By adoptingvegetative propagation method, uniform plants with desirable characters like high yield,resistance to pests, diseases and good quality could be established in Robusta as well as hybridsof Arabica.

(ii) Propagation through Seeds

For selection of seeds, good mother plants possessing superior agronomic traits like good yieldsand disease free nature are identified. At correct stage of ripening, mature berries are collected,carefully pulped, sorted and dried with special techniques. After sowing, germination takes placein about 45 days. Seedlings are replanted in fields.

(iii) Vegetative Propagation

Coffee can be propagated by cutting as well as by grafting techniques. In Coffee, two types ofshoots viz. Horizontal (plageotropic) and vertical (orthotropic) shoots are produced. Three typesof cutting can be obtained from orthotropic shoots viz. (a) single node cuttings (b) terminalcuttings and (c) mallet cuttings. There are particular methods to prepare each type of cuttings.Cuttings of all types are planted in perforated polythene bags, which are then arranged in coveredglass house like propagation trenches. Subsequently cutting are hardened for two months undershade and afterwards replanted in the main field in planting section.

In grafting, two types of technique are used (a) Seedling grafting and (b) Grafting of plants,called top working. Seedling grafting is useful in overcoming the problems of nematodes, soilborne root diseases and drought conditions. The grafting in mature plants is done for theconversion of old, unproductive, disease susceptible and off-type plants.

In recent times, `In-vitro' propagation through tissue culture is being encouraged by theGovernment Research Labs and private tissue culture firms. The grafted seedlings are planted inthe nursery baskets and kept under shade. After sprouting, these are transferred to second nursery

for 6-7 months and then planted in field at various spacing. Table 3.4 shows typical spacingbetween the plants.

Table 3.4 Spacing between plants

Type Variety Spacing(m) Arabica Tall 1.8x1.8, 2.1x2.1

Dwarf 1.5x1.5Robusta S.274, Old Robusta 3x3, 3.3x3.3

C xR 2.4x2.4, 2.7x2.7

After planting, the yield starts from 3` d year onwards, economic yield generally starts from 6`h

year.

Generally, Dadap is commonly used as a canopy shade. 1 to 2 m long stakes are planted forevery two plants of coffee when S-W monsoon commences (in June). During dry season, stemsof young Dadap are painted with dilute lime solution to protect them from sun, Silver Oaks canbe planted as shade belts in E-W direction to protect coffee from southern exposure at a spacingof 6 m apart within a row and 40 feet between two rows. The Silver Oak stands are alternatedwith Dadap rows. Permanent shade trees are planted at a wider spacing (30-40 feet) wherever theforest cover is inadequate.

Arabica has an economic life of 40-45 years whereas Robusta has a life about 80 years. The fruitbearing seasons are November to February for Arabica and Dec-March for Robusta.

3.3 Water requirement / Irrigation Practices

Coffee is predominantly cultivated as a rain fed crop worldwide. Coffee, being an evergreenplant, requires maintenance of soil & moisture during dry months. In coffee tracts of South India,the S-W monsoon zones predominantly receive more than 60% of rain during Jun-Sept and therest during N-E monsoon during Oct-Dec. In some years, the N-E monsoon tapers off by the endof Oct. itself. Robusta coffee being sensitive to drought. The first irrigation requires 25-38 mm ofwater after 20-25 days of cessation of N-E rains. The next successive irrigation has to be done atan interval of 20-25 days throughout the dry period up to the l s` fortnight of January. In Robustacoffee, blossom can be encouraged during the 2 °d fortnight of Feb. by applying 25-38 mm water.Irrigation is done with overhead sprinklers.

3.4 Use of Fertilizers

The amount of nutrient supply through fertilizers depends on yield and soil quality. In coffeecultivation, Nitrogen, Phosphorus and Potassium are considered as macro/major nutrients,Calcium Magnesium & Sulphur as secondary nutrients, while iron, manganese, Copper, Zinc,Molybdenum, Boron, Sodium and Chlorine as micro/minor elements. According to the estimatesof the CCRI , one tonne of clean coffee removes approximately 40, 7 and 45 kg of N, P2O5 andK2O for Arabica and 45, 9 and 58 Kg of these major nutrients for Robusta Coffee respectively.Good practice dictates that fertilizers are applied in many splits as possible, not less than threeannually i.e. during pre-blossom, mid monsoon & post monsoon. Between fertilizer application

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and liming 30 days gap should be given. Agricultural lime is applied to correct the pH of soil.Considering the factors like crop removal of nutrients, nutrient loss through leaching & fixationand Fertilizer Use Efficiency (FUE) in coffee soils, fertilizer doses for different quantities ofyield per unit area are given in Table 3.5. Application of fertilizers increased in a substantialmanner over a period 1991-1998 in major coffee growing districts of Karnataka are shown inTable 3.6.

Table 3.5 Suggested Fertilizer Dosage for Coffee (kg NPK/ha)

Yield (Kg) Pre Blossom Post Blossom Mid Monsoon Post Monsoon Total

Arabica500 20:15:20 20:15:20 20:15:20 60:45:60750 30:20:30 30:20:30 30:20:30 90:60:901000 30:20:30 30:20:30 30:20:30 30:20:30 120:90:1201250 40:30:40 40:30:40 30:20:30 40:30:40 130:100:130

Robusta500 20:15:20 20:15:20 40:30:40750 30:20:30 30:20:30 60:40:60

1000 30:20:30 30:20:30 30:20:30 90:60:90

Table 3.6 Application of Fertilizers (MT)

District Year N P K Total

Hassan 1991 18994 5376 7951 32321

1998 28971 6333 11331 46635

Chikmagalur 1991 12940 4056 6703 23699

1998 19911 6048 12557 37416

The fertilizer dosages for high yield coffee are shown in Table 3.7.

Table 3.7 Typical fertilizer dosages for high yield coffee

Type N P K TotalArabica 90 60 90 240

Robusta 90 60 90 240

Typical fertilizers used are: Urea, Muriate of Potash, Diammonium Phosphate, other proprietaryphosphates e.g.Factamphos 20:20, Mussoriephos etc. rock phosphate. Agricultural lime is alsoused for soil pH correction. It may be however be noted that actual usage depends on soil, leaf,yield and other location factors. As recommended by the CCRI the plant sustenance dose is 80kg/ha(30:20:30) per year.

3.5 Effect of Fertilizer on Water Quality:

Using of more fertilizers, in a crop like coffee, it is difficult to assess the effect on the waterquality of Rivers/streams. An attempt may be made to consider the trends of use of fertilizersvis-à-vis general water quality in a large coffee growing area. In Karnataka, Chikmagalur &Hassan districts are major coffee growing areas which discharged into rivers Tunga & Bhadra.For this purpose, a general trend of selected water quality parameters with reference to certain

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selected parameters on the basis of available data could be studied as an example and trends(1991-1994) are presented in Table 3.8.

Table 3.8 Water Quality of R.Tunga d/s of Shimoga Selected parameters, mg/l

Year Nitrate + Nitrate Free Ammonia PhosphateMax. Min. Mean Max. Min. Mean Max. Min. Mean

1991 0.4 0.2 0.287 NA NA NA NA NA NA1993 0.708 0.1 0.221 0.08 0.0 0.002 0.010 0.0 0.0101994 0.704 0.08 0.349 0.025 0.006 0.017 0.020 0.0 0.013

Table 3.9 Water Quality of R.Bhadra at d/s of KIOCL Road Bridge, Near Holehunnur,selected parameters, mg/l

Year Nitrogen PhosphateMax. Min. Mean Max. Min. Mean

1997 0.131 0.017 0.05 0.3 0.001 0.111

From the above tables it can be concluded that the increase in concentration levels of selectedwater quality parameters shows the increase in fertilizer use over the years (except for R.Bhadrafor which comparable data are not available). Table 3.9 shows Nitrogen & Phosphateconcentrations for the year 1997. It is noted that the concentrations are not high. It is seen thatthe maximum concentrations are significant because of low flow during pre-monsoon period inthe river. Hence, usage of fertilizers shows impact on the water quality partially due toagricultural run-off.

In view of the pollution potential of nutrients due to run-off, leaching and groundwater recharge,alternatives to inorganic fertilizers need consideration. In this regard, recycling of bio-degradablewaste can largely be minimized by the addition of inorganic fertilizer. In many coffee estates,composts are already being used in conjunction with inorganic fertilizers. In Indian coffeeplantations, such wastes may include shade tree leaf litter, coffee leaves and prunings, weededmaterials, fruit skin pulp and cherry or parchment husks. The following are estimates of variouswastes:

Table 3.10 Estimated Nutrient Potential of Various Wastes

Waste NPK kg/ha/year N P205 K20

Shade trees-leaf litter 40-60 30-33 40-60Dadap-tender branches, degradable stakes & leaves 96 8 67All- in from coffee field expect Dadap Waste 84-95 40-42 108-123

The above table indicates the reduction in application of inorganic fertilizers, cost of inputs andin terms of pollution by recycling the bio-degradable waste.

3.6 Diseases of Coffee Plant & Use of Pesticides/Fungicides

Arabica & Robusta coffee are susceptible to fungal diseases. Bacterial & Viral diseases have notbeen recorded so far in India. Arabica is more susceptible to diseases than Robusta. The common

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diseases and their causative organisms are presented in Table 3.11. The table also indicates trade& common names of pesticides/fungicides used to control these diseases. The common diseasethat mostly occurs in coffee field is leaf rust which is caused by Ameba Hemileia Vastatrix. Inthis disease the pale yellow spots on the lower surface of leaves appear, later turning orange-yellow powdery mass consisting of uredospores. To control this disease, Bordeaux mixture sprayis adopted. The spray schedule is presented in Table 3.12.

Table 3.11 Major pesticides / fungicides Used to treat Coffee Diseases

Name of the Causative Recommended Alternative names Industry namesdisease organism pesticide/fungicide

1. Leaf rust HEMILIEIA Prophylactic Bordeaux Oxycarboxin is known Bordeaux mixtureVASTATRIX mixture of systemic as Plantvax also as (90.5%)

fungicides oxycarboxin D735 Triadimefon is Carboxin sufoxideor triamedimefin known as Bayleton Triamedifen

also as Acizol, Amiral2. Black rot Koleroga noxia Bordeaux mixture or Benomyl is known as Benomyl(1%)

benomyl Bavistin also agricit Carboxinetc. Carboxin isknown as Vitavax

3. Pink Corticium Same as black rotdisease Salrnornicolor

4. Root i) Forces noxius Soil drench with benomyl Benomyl is known as Benomyldiseases ii) Poria or carboxin Bavistin also Agricit Carboxini) Brown hypolateritia etc. carboxin is knownroot iii) Rosellinia as Vitavax

disease buisodes andii) Red root Rosellinia arcuata

diseaseiii) Blackroot

disease5. Berry Cercospora Bordeaux mixtureblotch cofeeicolaNursery Cercospora Captan or maneb or Captan is known as Captandiseases coffeicola captafol Caparo, Captanex,

Maneb6. Berry-eye- Captec, Captazelspot Maneb is known as Captafol

Dithane-22,Farmaneb, Manesanor Monex captafol isknown as Foltaf

7. Collar rot Rhizoctonia solani Treat seeds with benomyl Mancozeb is also Mancozebor carboxin or soil drench known as Dithane-45with captan or mancozeb

8. Stem Not by parasites Avoid Bordeaux mixture;wasting but by toxicity from use organic pesticides

(Kondli) copper basedpesticides

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Table 3.12 Spray Schedule for leaf rust Control

S.No. Spray Schedule1. Bordeaux mixture 0.5% (1 kg CuSO4) : Pre-blossom(Feb-March)

1 kg CuO:2001) Pre-monsoon(May-June)Pre-monsoon(Sept-Oct)

2. Plantvax 0.03% (300m1/2001) Pre-monsoon(May-June)Mid-monsoon(May-June)Post-monsoon*(Plantvax or Bordeaux mixture)

3. Ba Teton 0.02% (160 gm/2001) Pre-monsoon & Post monsoon

Black rot (Koleroga) is considered to be the second important disease affecting Arabica &Robusta during the monsoon period. This disease is common in all the coffee growing areas inIndia, which come under the influence of heavy S-W monsoon. Crop loss of 10-20% is recordedin severely affected areas. The most striking symptoms are blackening and rotting of the infectedleaves, developing berries & young twigs. This disease is controlled by the following ways:

(i) Removal and destruction of the affected leaves and berries in the initial stageunder wet conditions.

(ii) Adequate coverage of Bordeaux mixture 1.0% on both the surfaces of leavesand also to the developing berries just before the onset of monsoon and duringthe break in monsoon (end of July or early August).

(iii) Centering & handling of the bushes by removing criss-cross branches (6inches radius of the shade trees fallen on the canopy of the coffee bush beforeimposing pre-monsoon spray).

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4.0 ENVIRONMENTAL EFFECTS OF PESTICIDES/FUNGICIDES USED INCOFFEE PLANTATION

4.1 General

For control of pests in coffee plants, several fungicides and pesticides are used. Integrated PestManagement methods are given in "Coffee Guide" authored & published by the Central CoffeeResearch Institute, 1996. In this section, the environment effects of some of the commonly usedmajor pesticides/fungicides have been dealt with the toxicological and environmental effects ofpesticides and fungicides. The effects depend on the following:

➢ Soil characteristics➢ Chemical factors

Soil characteristics generally include:

1. Soil texture

2. Soil pH

3. Soil moisture

4. Soil temperature

5. Soil micro-organisms

Chemical factors of the Pesticides/Fungicides include:

1. Solubility in water

2. Chemical degradation

3. Microbial degradation

4. Photo degradation

5. Volatilization

The fact of pesticides in the environment is a complex phenomenon. The process depends onfactors listed above. A simplified pathway of fate of pesticides in environment is shown in Fig.4.1.

The following sub-section deals with the toxicological and environmental effects of some majorfungicides/pesticides used in coffee plantation as indicated in Table 3.11.

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CPhoto—degradationRun-off with particles

Fig. 4.1 Fate of Pesticides in Atmosphere

4.2 Major Pesticides/Fungicides

i) Carboxin (A 5,6—Dihydro -2—methyl-n-phenyl-1, 4-oxathin-3-carboxamide)

Carboxin is a systemic anilide fungicide used to treat seeds in order to prevent and controlexisting diseases.

Environmental Fate

a) In soil and groundwaterCarboxin is rapidly degraded to carboxin sulfoxide in soil. It has a low persistence in soil.Products that are formed are carboxin fulfone, hydroxy carboxin and CO2. Carboxin does notreadily adsorb in soil. Both carboxin and the sulfoxide are mobile and can leach to groundwater.

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b) In WaterIn water, carboxin oxidizes to sulfoxide and sulfone. Blue green algae degrade the pesticiderapidly.

Ecological EffectsCarboxin is highly toxic to fish. It is non toxic to freshwater nonvertebrates. Toxicity birds arealso low. The compound does not accumulate in animal tissue. Plants grown form seeds treatedwith carboxin after six weeks shows no presence of the compund.

Carcinogenic EffectsCarboxin does not causes cancer. The study shows rates fed with carboxin had no evidence ofincreased tumor frequency.

ConclusionCarboxin/Oxycarboxin can be concluded to be fairly safe General Use Pesticide (GUP), whenthere is no fish culture ponds fed by leaching water from coffee plantations.

(ii) Triadimefon(1-(4-Chlorophynoxy)-3 ; 3dimethyl-1-(1 H-1,2,4 -trizol-1 -yl) butanone)

Triadimefon is a systemic fungicide in the triazole family of chemicals. The compound may alsobe found in formulations with other fungicides such as captan , carbendazim, folpet ect.

Environmental Fate

a) In Soil and GroundwaterTriadimefon is moderately persistent in soil, the breakdown depends on the soil type.Triadimefon and its breakdown products are moderately mobile and have the potential to reachthe groundwater.

b) In WaterThe compound is very stable in water. In water with varying acidity the compound persisted tothe extent of 95%. It does not undergo hydrolysis.

Ecological EffectsTriadimefon is slightly toxic to birds. It is also slightly toxic to fish. The compound is nontoxicto useful insects.

Carcinogenic EffectsDietary study in mice shown no evidence of increased tumor frequency but increased livercellhypertrophy. Increased livercell adenoma was detected but no carcinoma.

ConclusionTriadiameforn can be concluded to be a safe General Use Pesticide (GUP). But it may havepotential to induce defective neuro behavioural patterns, hence should be avoided from beinginhaled. Therefore, spraying, specially by female plantation workers, should be avoided and thepaste or wattable powder should be used.

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(iii) Benomyl (methyl-I- [(butyl amino) carbonyl]-H-benzimidazonl-2-yl-carbamate)

Benomyl is a systemic benzimidazole fungicide that it is selectively toxic to micro organismsand to invertebrates, especially earthworms. It is used against a wide range of fungal diseases.

Environmental Fate

a) In soil and groundwaterIt is highly persistent in soil. Benomyl is strongly bound to soil and does not dissolve in water toa significant extent. Therefore it's potential to reach groundwater is low.

b) In WaterBenomyl completely degrades to carbendazim within hours in acidic or neutral water.Carbendazim is used as a fungicides under trade name of Baristin.

Ecological EffectsBenomyl is moderately toxic to birds. It is very toxic to fish. A single application of Benomylcan substantially reduce some soil dwelling organisms. It is very toxic to earthworms. It isabsorbed by plants, it accumulates in leaf veins and at the leaf margins.

Carcinogenic EffectsOccurrence of liver tumors has been found in life-time studies in female mice. Carbendazimhave similar toxicological properties.

ConclusionBenomyl is non systemic fungicide. However, it accumulates in veins and leaf margins in plants.Hence it has potential of Bio-magnification. It affects earthworms as well as slows down mixingof soil; it may affect paddy plantation downstream to coffee plantations: -It is non-toxic through-the inhalation route, hence safer for spraying. It may also affect fish: -culture if the leachingwater from plantation reach culture ponds.

iv) Captan3a,4,7,7a-tetrahydro-2-[(trichloromethyl)thio ]-1-H-isoindole-1,3,(2H)-dione)

Captan is a non-systemic phthalimide fungicide used to control many diseases.

Environmental Fate

a) In soil and groundwaterCaptan has low persistence in soil.

b) In WaterCaptan readily degrades in near neutral water.

Ecological EffectsCaptan is practically nontoxic to birds. Captan is highly toxic to fish. It is moderately toxic toaquatic nonvertebrates. Captan has a tendency for accumulation in living tissue. Therefore, it hasa potential for bio-amplification. Some seeds may be injured by captan at high dose.

15

Carcinogenic EffectsThere is a strong evidence that captan causes cancer in mice at high doses. In addition, captan ischemically similar to folpet and captafol which produce cancer in animal. Tumors ofgastrointestinal tract as well as kidney has been observed in animals fed with captan.

ConclusionCaptan is a General Use Pesticide (GUP), though not using on food crops in USA from 1989, itmay affect fish culture downstream to coffee plantations. Due tro its carcinogenicity, it must behandled carefully by plantation workers. It can cause eye and skin irritation to workers exposedto high concentrations of captan in air which is caused by spraying.

v) Maneb(Manganese ethylenebis(dithiocarbamate)(polymeric))

Maneb is an ethylene(bis) Dithiocarbamate fungicide used in the control of early and late blightsand many other diseases.

Environmental Fate

a) In soil and groundwaterIt has low persistence in soil, but it gets converted to products (ethylenethiourea etc.) which aremore persistent. Since they strongly bind to soil and have low solubility in water, they do notpercolate into groundwater.

b) In waterIn water, Maneb degrades completely within one hour under anaerobic aquatic conditions.

Ecological EffectsManeb is practically non-toxic to birds. Maneb is highly toxic to fish and other aquaticorganisma. Maneb treatment on crop foliage may be toxix to livestock.

Carcinogenic EffectsIn one study Maneb did not show significant carcinogenicity in laboratory animals. But inanother study malignant tumors were observed in rats injected with maneb. Therefore noconclusion about its carcinogenicity can be drawn.

ConclusionManeb is a carbamate fungincide. Though, it is nontoxic by the ingestion route, it is toxic by theinhalation route. Acute exposure to Maneb may result in hyperactivity, incoordination, nausea,vomiting and respiratory paralysis. Therefore, spraying should be avoided and the wettablepowder form should be used. As other fungicides, it may affect fish-culture downstream tocoffee plantations.

4.3 Overall Conclusion

The pesticides/fungicides used in coffee plantation do not pose any serious threat toenvironment. Their use will not affect other agricultural activities except for fresh-water fishculture downstream to coffee plantations (if any), as most of the fungicides used are toxic to fish.Carboxin and Triadimefon have the potential to leach to groundwater. Use of pesticides likeCaptan and Folpet discourages for their carcinogenicity. The use of Bordeaux mixture should beweighed against the occurrence of Kondli.

16

5.0 PROCESSING OF COFFEE

5.1 General

In India, coffee is processed in two ways:

(i) Wet processing by which parchment coffee is prepared(ii) Dry processing by which cherry coffee is prepared

Parchment coffee prepared by the wet method is popular in the market. For preparation of bothparchment & cherry coffee, coffee fruits is picked as & when they become ripe. The under - ripe& over - ripe fruits cause deterioration in quality and is rejected. The collecting bags forharvested fruit are washed & dried frequently. Bags in which fertilizers, pesticides & fungicidesare stored cannot be used for this purpose.

5.2 Preparation of Parchment Coffee

Parchment coffee processing involves following steps:

(i) Pulping(ii) Demucilaging & Washing(iii) Drying

5.2.1 Pulping

Fruits are fed to the pulper through siphon arrangements to ensure uniform feeding. Uniformfeeding ensures proper removal of skin and prevents cuts and choking of pulper. Preparation ofcoffee by wet method requires pulping equipment & adequate clean water. The pulpedparchment should be sieved to eliminate any unpulped fruits & fruit skin. Generally therecirculation of water is done at pulping section, recirculated water may be used only for oneworking day, otherwise the quality of water may deteriorate.

5.2.2: Demucilaging & Washing

The mucilage on the parchment skins may be removed by:

➢ Natural fermentation➢ Treatment with alkali➢ Enzymatic method➢ Frictional removal in machines like Aqua pulpa

5.2.2.1 Natural fermentationFermentation is carried out in concrete tanks usually having size of (3m x 1.5m x 1.2m) with asloping ground which accommodate approximately 4.5 cum of beans. One tonne of fruitsapproximately yield 0.5 cum of wet parchment; this quantity requires a tank space of about 0.6cum. Thus for production of 1 tonne marketable coffee, 3.6 cum of tank is required. These tanks

17

are constructed in brick masonry with smooth surface sloping floor running towards the outlet.Fermentation is controlled so that it is wholly alcoholic, not acidic. Usually acidic fermentationoccurs under dry, high temperature & high pH conditions in the top 10 cm layer. Acidicfermentation produces unpleasant odours, this is avoided by covering the fermenting mass. Themucilage breaks down in the process of fermentation. In case of Arabica it takes about 24-36 hrs,while in Robusta even 72 hrs is not sufficient. It is therefore, desirable to resort to either alkalitreatment or frictional removal for complete removal of mucilage.

5.2.2.2 Treatment with AlkaliRemoval of mucilage by treatment with alkali takes about 1 hr for Arabica & 1.5-2 hrs. in case ofRobusta. The beans obtained after pulping are drained off excess water & spread out in the vatsuniformly and furrowed with "gorumanes" (wooden ladles with a long handle). A 10% solutionof NaOH dissolved in evenly applied into the furrows using a rose cane. About 1 kg of NaOHdissolved in 10 litres of water is sufficient to treat forty litres of wet parchment. The parchment isagitated thoroughly by means of "gorumanes" so as to make the alkali come in contact with theparchment. When the parchment is no longer slimy and makes a rattling noise, clean water is letin.

5.2.2.3 Enzymatic Removal of MucilageThe time of fermentation process could be reduced by use of pectinolytic enzymes.Concentration of enzymes & temperature of the ambient air determine the fermentation time.

5.2.2.4 Removal of Mucilage by FrictionThis method is widely used, particularly in medium and large estates. There are pulpers such as"Aqua Pulpa" which pulp & demucilage the beans in one operation. These machines areespecially suitable for demucilaging robusta parchment. The adjustment of machine is essentialto obtain uniform pulping & demucilaging. Uniform feeding using siphon arrangement is veryessential to rectify the defect of naked & bruised beans. Pre-fermentation of pulped coffee for 12hrs in case of Arabica & 24-36 hrs in case of Robusta is desirable before letting into aqua washerfor effective removal of mucilage.

5.2.3 DryingThe next stage in processing is drying the parchment in the sun until the moisture content issufficiently reduced to permit storage of beans till they are dispatched to curing works.

The wet parchment coffee has a moisture content of around 50% and has to be brought down to10%. Surface drying is best, carried out in trays with wire-mesh bottom. These trays may bemounted on wooden poles at a height of 75-90 cm above floor level. The parchment is spread intrays to a thickness of 4-7 cm. The coffee may be turned repeatedly to facilitate quick drying andto prevent cracking of parchment skin. Surface drying in trays may take about 24-48 hrs. a trayof 1.75m x 1.75m with 7 cm height side walls can hold 3-4 tits of parchment or cherry spread toa thickness of 4 cm. Drying yard requirement for drying 1000 kg clean coffee for differentspreads are as follows:

- Parchment equivalent, 4 cm spread = 9.5 x 9.5m- Parchment equivalent, 7 cm spread = 7.3 x 7.3 m

Cherry equivalent, 7 cm spread = 11.0 x 11.0 m

18

After the surface drying the parchment is spread on clean tile or concrete drying floor. Theparchment is required to be dried slowly in the later stages by spreading to a thickness of about7-10 cm. Drying should be steady & continuous. Storing & turning over at least once an hour isnecessary to facilitate uniform drying. The parchment should be heaped up in the evening & keptcovered until next morning. For covering, polythene sheets are used. It is desirable to keep theparchment covered during the hottest part of the day, between noon & the early part of theafternoon. Sun drying may take about 7 to 10 days under bright weather conditions. At the rightstage of dryness the parchment becomes crumbly and the beans split clear without a whitefracture when bitten between the teeth and the dark spots at either extremity of the beans justabout disappear. This indicates that the parchment is ready for the test weighing. Drying iscomplete when sample forlits of coffee record the same weight for 2 consecutive days. At thisstage coffee is shifted to stores where it is spread on the floor for 2-3 days to attain theuniformity in the moisture content. The coffee may then be bagged into clean new gunnies.Coffee of different lots is bagged separately.

5.3 Preparation of Cherry Coffee

For preparation of cherry coffee, fruits should be picked as & when they ripen. The fruits shouldbe spread evenly to a thickness of about 7-8 cm on clean drying ground. It is desirable thatdrying is carried out on tiled or concrete floors. Coffee should be stirred & ridged at least once inevening hours. The cherry is dry when a fistful of the drying cherry produces rattling soundwhen shaken and a sample forlit records the same weight on two consecutive days. The cherrywould be fully dry at the end of 12-15 days under bright weather conditions.

5.4 Curing Works

After drying it is taken by the farmers to the curing works. In Curing works the coffee beans areput into peeler machine in which the outer parchment is taken off through a process of rubbing.After which it is sent to the Polishers; here the beans are polished to remove the slightly whitishremains of the outer parchment. It is then graded in graders where it is sieved according to thesizes. Grading and sorting were done (and is still practiced) manually on a traveling conveyor; inmodern curing works it is done by optical fibre colour- sorters and electrically operated sieves.The beans are sold as such for further use. The beans may be roasted & grinded to producecoffee powder. This is done by private parties with the help of electric roaster & grinder. It isfinally used as filter coffee.

5.5 Instant Coffee

Coffee beans are cleaned to remove foreign matters and then roasted to a degree to get thedesired final product. Roasted coffee beans are ground & extracted with hot water to leach outcoffee soluble solids in extract form in a battery of extraction columns. Coffee extract isconcentrated to a higher concentration by evaporating water in the evaporator and then dried toinstant coffee powder in the spray drier. The process flow diagram of Instant Coffee Productionis shown in Fig.5.1.

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Green Beans

Dumping

Cleaning DustDust Removal

Blending

Roasting

Destoning

Grinding

Rework

Filtered ReworkExtractionFiltration AdditionRWLi.

I Clarification I

Thermal Concentration j

Spray Drying

I Sieving

I Powder Collection

Fig. 5.1 Flow Diagram of Instant Coffee Production

5.6 Selection of Units for In-depth Studies

Based on the type of units and processing described in this section, it is clear that production ofcoffee beans from berries by small farmers does not produce any appreciable pollution orenvironmental problem. Production of beans by wet method by medium and large cultivatorshowever need attention owing to the nature and extent of water pollution.

From the cultivators, the beans are taken to curing works, which is an entirely dry process.Nevertheless, it deserves attention with respect to air pollution (due to fuel burning for auxiliarypower source) and generation of solid waste (husk).

20

Unlike wet processing of coffee and coffee curing, which operate only a few months in a year,production of instant coffee is done in large or medium industries operating throughout the year.It has potential of water, air and noise pollution and thus deserves particular attention.

In view of these considerations, it was desired to carry out in-depth studies for one unit each withrespect to the following:

➢ Instant coffee industry ( Hindustan Lever Ltd, Mysore)➢ Large coffee plantation( Tata Coffee Ltd, Nullore & Hope division( Kodagu Dist) and

Consolidated Coffee Ltd, Hassan)➢ Coffee curing works(Mysore Coffe Curing works, Chikmangalure)

Karnataka being the largest producer of coffee and having also the largest concentration of units,the in-depth studies were carried out in Mysore, Chikmagalur and Hassan districts.

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6.0 IN-DEPTH STUDIES IN SELECTED COFFEE PROCESSINGINDUSTRY AND COFFEE PLANTATION ESTATES

A. Instant Coffee Manufacturing IndustryHindustan Lever Ltd., Mysore

6.1 General

Hindustan Lever Limited (HLL) has instant coffee processing unit in Hebbal Industrial Area,Mysore. HLL manufactures instant coffee under the trade names of `BRU" and "Green Valley",most of which are sold in the domestic market. The product is a mix of instant coffee and chicoryroots. The plant has an annual production capacity of 3000 tons. Raw materials used are greencoffee beans and roasted chicory roots. Coffee beans are obtained from coffee curing works inand around Mysore and Jamnagar. Production of year 1997-98 was 2270 tons, i.e. a plantutilization capacity of 75.7% was achieved. The plant operates on a continuous basis.

6.2 Manufacturing Process

(i) Green coffee beans are cleaned to remove foreign matters and then roasted to a degree toget the desired final product. Roasted coffee beans are grinded and extracted with hotwater to leach out soluble coffee solids in extract form in a battery of extraction columns.Coffee extract is concentrated to a higher concentration by evaporating water in theevaporator and then dried to coffee powder in spray driers. The cleaning of green beans isdone in a series of sieve-shakers and magnetic separators to remove sticks, stones, nails,etc., and dust. Dust is blown with air and arrested in cyclone collectors.

(ii) During roasting in electrically heated roasters, moisture is removed along with off gases.Chaff is also removed in the process. HLL roaster capacity is 2000 kg/h (based on 330working days per year) whereas the grinder (electrical operated) has a capacity of 1000kg/h. The higher capacity of roaster is to roast in batches to save energy becauseaccording to moisture content in green cleaned beans the required roasting time isadjusted.

(iii) In instant coffee production, the main process is extraction of soluble coffee portion. Theprocess flow diagram is shown in Fig 5.1.

(iv) In the extraction column roasted chicory is mixed according to product specification*.Soft Water from boilers at a temperature of 175°C at 20 kg/cm 2 pressure is introduced.The extracted liquor contains 14% soluble coffee (it also contains suspended solids),which requires being further concentrated. This is done by first passing the liquor throughcentrifugation to remove suspended solids and then by triple effect evaporation. Duringevaporation the aroma, which contains mostly volatile organic compounds is separated inchilling columns where aroma is arrested. The aroma is very important component of theproduct. `BRU' contains 30% Chicory; `Green Valley' contains 47% Chicory.

After evaporation, the decoction contains 40 to 45% concentration of soluble coffee. Thechilled aroma is sent back to extraction columns thereby making it a closed loop. This is

22

then sent to the spray drier. The spray drier is a closed chamber under vacuum (3mmWC) where the decoction is sprayed from the top alongwith hot air (200-210 °C) in co-current motion. The purpose of co-current motion is to capture fine powders in aneffective manner. Hot air is generated in hot air generator by burning diesel with excessair. The collected instant coffee powder is fluidised (to prevent formation of lumps) bydehumidified air. The powder is then sent for packing in pouches.

6.3 Material, Energy & Water Balance

Typical production losses reported in the literature (Shankaranaya, 1994) indicates that 100gms of green coffee yields 85 gms of roasted coffee which in turn yields 38.7 gms of instantcoffee. During the in-depth study of HLL — Mysore, it was found from the last 3 months' datathat following losses can be taken as typical:

Table 6.1 Material Losses in HLL, Mysore

Sl. No. Loss Waste

1. Cleaning loss = 1.00% Stones/Sticks2. Roasting loss = 12.25% Chaff3. Extraction loss = 46.49% Spent Coffee4. Packing loss = 0.8 1 % Powder

Total = 60.55%

This indicates that out of 100gms of raw coffee beans, 39.45 gms of instant coffee is producedby HLL.

The use of energy (as electricity bought from KSEB as well as electricity generated by HLLusing HFO and LFO) for the last two years are summarised in Table 6.2.

Table 6.2 Energy Use in the HLL Instant Coffee Plant, Mysore

Sl. No. Source/Parameter 1998 19971 KSEB Electricity, kWh 13,30,746 11,93,3602 -Do-, GJ 4,791 4,2963 HFO, GJ 64,824 71,5864 LFO, GJ 91,046 91,9865 Total Energy, GJ 1,60,661 1,67,86867 `

Coffee Production, MT. ' Energy Use GJ/Ton

2,270`` 70.8., r

2,12079.2'

8 -Do- kWh/Ton 19.7 22.0

It is seen that specific energy consumption has improved in 1998 compared to that in 1997.

HLL typically uses about 600 kl of water daily. There are three uses — (i) process, (ii) drinking,canteen, toilet, etc. and (iii) cooling water. The overall wastewater generation over the last twoyears is given in Table 6.3.

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Table 6.3 HLL — Wastewater Generation (kl)

Si No. Wastewater 1998 1997

1 Effluent—ETP 1,08,858 1,08,8792 Cooling Water Blowdown 3,300 3,200

Considering, on an average 330 working days a year, the rate of total wastewater generation isestimated at 340 kld (both in 1998 and 1997). Considering 20 kld as wastewater discharge fromhuman use, the total wastewater generation comes to 360 kld which is 60% of overall waterinput. The loss of 40% can be attributed to (i) evaporation losses, (ii) as moisture with spentcoffee waste and ETP sludge and (iii) drift and consumption losses.

6.4 Genesis of pollution and identification of pollutants

In instant coffee processing, all three kinds of pollution occur — air, water and noise.

6.4.1 Water Pollution & Wastewater Treatment

The first part of instant coffee processing (i.e. up to grinding) is dry. Thereafter, the process iswet up to spray drying. During this middle part, wastewater is generated. Wastewater isgenerated mostly from the spent coffee waste. Of the total water usage of 600 kld., part goes for(i) cooling make-up, (ii) the process water including boiler and (iii) domestic water use (i.e.drinking, canteen, toilet, etc.). The wastewater generated is 310 kid and domestic wastewater isin the order of 20 kld. The process wastewater goes to the ETP while the domestic goes to theseptic tank and soak pit. Photo 3 shows a general view of the ETP. A close-up of Aeration Tankis shown in Photo 4. On an overall basis, therefore about 50-55% wastewater is generated on thebasis of overall water use excluding cooling water blow downs.

Considerable variation is noted in the raw wastewater characteristics observed from time to time.However, the following observations can be made:

(i) Wastewater is acidic and require neutralization (monitored sampletaken afterneutralization)

(ii) BOD is quite high (except Sept '98 observation)(iii) BOD: COD ratio is low @11-14% indicating that it is not readily biodegradable; also,

nutrient addition is required.(iv) Presence of colour is rather difficult to remove due to presence of dissolved organic

substances particularly, tannin and lignin.

24

Photo 3 : General view of HLL Wastewater Treatment Plant

Photo 4: Close-up View of Aeration Tank, HLL

The characteristics of raw wastewater is given in Table 6.4

Table 6.4 HLL — Typical Characteristics of Raw Wastewater

Parameter Feb '98(2)

Sept '98(3)

MonitoredMarch 2001

Colour Brown Brown Brown

Temp °C * * 29.0pH 4.5 5.65 9.43

BOD (5 day, 20 °C) 1,710.0 285.0 646.0

COD 11,918.0 2600 3702

S.S. 1,340.0 126.0 90.0

TDS 520.0 700 2110

Cl - 50.0 60.0 8.5

SO4 - N.D. 288 256

Phosphate * * 40Fluoride * * 0.45

Ammoniacal N * * 7.05Kjeldal N * * 12.50

Oil & Grease * * 8.50Phenolic Compound * * NilResidual Chlorine * * Nil

Sodium Absorption Ratio * * 1.1

Notes

*Not recorded2&3 : Results monitored by KSPCB4 : Results monitored in March 2001 during in-depth study

Industry employed two stage activated sludge process (Fig 6.1); Urea and di-ammoniumphosphate are added as nutrient. For neutralization, caustic soda is used. For removal of colour,sodium hypochlorite is used. Poly-electrolytes and ferric alum are used to bring down totaldissolved solids. Typical characteristics of treated effluent are presented in Table 6.5

Table 6.5 HLL — Characteristics of Treated Effluent

Parameter

Feb`97

April`97

Sept`97

Nov`97

Dec`97

Feb`98

GeomMean

MonitoringMar,2001

Feb`05

Limitsofconsentorder

H 6.6 7.2 5.3 7.0 8.0 5.2 6.6 6.94 8.17 6.0-8.5BOD 3 34 12 15 8 22 11.6 10 10 "'' 30COD 152 348 186 162 116 183 177.5 93 82 250S.S. 216 90 50 70 30 40 55.6 14 208 100TDS 1164 1560 975 650 955 975 996.4 1924 2085 2100Cl - 70 196 150 50 50 100 98.1 206 NA 1000'

SO42- 40 214 334 320 660 464 224.9 520 NA 1000NH3-N 1.2 1.8 1.5 5.39 2.53 50

SAR 15.0 15.0 1.39 2.79Source: KSPCB and Monitoring by ENC, CPCB(Feb 05)

The results show satisfactory compliance (BOD and COD), except once. The effluent is used forgardening for which the standards enforced by KSPCB seem to be stringent.

The cost of treatment of wastewater in shown in Table 6.6.It is seen that as a percentage of overall cost of production it is 0.26% which is consideredreasonable.

Table 6.6 Operating Cost of Effluent Treatment Plant

Cost of Cost per Annum (Rs.)Non Ferric Alum 4,61,920Sodium Hypochlorite 1,52,188Urea 29,256DAP 21,500Sulphuric Acid 8,970Poly-electrolyte 21,757Caustic Lye 1,87,113Cost of Man Power 3,49,320Cost of Power 9,68,400Cost of Repair 51,000Depreciation 2,04,619Total 24,56,043

Impact of effluent treatment on cost of production: Rs. 1160/TAs percentage of overall conversion cost: 0.26%

27

Wastewater UtilisationThe entire amount of treated wastewater is reused as irrigation water for the garden andlandscaped areas within the factory premises. The vegetation growth was found to be luxuriant.The practice is considered satisfactory.

6.4.2 Air Pollution and its control

The sources of air Pollution are as under:

- Hot air generation (by diesel burning)- Pneumatic Handling of beans- Cleaning of beans- Roasting- Diesel electric generators- Boilers

In the pneumatic handling of beans, mostly dust and chaff are emitted. In hot air generator, dieselis burnt; the hot gas passes through spray drier. The exhaust contains SPM, SO2 and alsoaromatic compounds of coffee. The boiler exhausts emit SPM, SO2 and NO as products ofcombustion. For dispersal of SO2, stack (chimney) heights are stipulated by the KSPCB in theirconsent order. For control of SPM, cyclone/bag filters are stipulated whilst cyclones and multi-cyclones are installed by HCL. For control of odour the industry has installed catalyticconverters to completely burn the VOCs containing coffee aroma. The results of stackmonitoring are shown in Table 6.7.

Table 6.7 Air Pollutants in Stack Emissions from HLL, Mysore

Si.No.

Stack/ Height (m) PCD Pollutant conc.m m3

Limit inconsent order

1. GB Airveyor/23 Cyclone SPM : 40.0 SPM — 1502. GB Silo/23 Cyclone SPM : 99.63 Stack heights3. Roaster/23 Cyclone SPM : 53.85

SO2 - 0.85are as perconsent order

4. Spray Drier/54 Multi-cyclone SPM: 89.0

5. Boiler/45 Multi-cyclone SPM: 98.34SO2 - 4.65

6. 1000 KVA DG set #1/22 SPM : 50.28SO2 -2.4

7. 1000 KVA DG set #2/22 SPM: 75.66SO2 - 0.35

8. 437.5 KVA DG set#3 /7 SPM : 94.97

28

There was no smell of coffee outside the plant building. The quality of ambient air is given in theTable 6.8.

Table 6.8 HLL — Ambient Air Quality (conc. in µg/m3 )

Location SPM SO2 NO,

Near Security 66.6 17.0 14.0

Fugitive Emission

The ambient air quality data indicate that there is no evidence of fugitive emission outside theplant. Most importantly, there is no smell of coffee within the premises (outside the plantbuilding) because in the processing unit catalytic converters are installed at stacks.

6.4.3 Noise Pollution

The plant is contained in a tall 5-6 storied building. Noise is generated_in pneumatic handling,blowers, sieves and rotating equipments. The results of noise monitoring during plant visit areshown in Table 6.9.

Table 6.9 HLL — Results of Noise Monitoring (15m from source)

Source Equipment Noise Level dB (A) TypeRoaster 80-82 Continuous when in operationClarifier-Evaporator 80-82 ContinuousHot air generator 98 Continuous,

The hot air generator is in an enclosed space and worker presence is required only occasionally.However noise reduction is required in this equipment to satisfy the stipulated noise level. In theconsent letter issued by KSPCB, the day- time noise level is required not to exceed 75 dB (A)and 70 dB (A) during night- time.

6.4.4 Solid Waste Management

Main solid waste generated is spent coffee waste because coffee contains only around 42%soluble coffee, which is converted to final product, the rest being spent solids. Spent coffee wasteis sent to Hosur plant as boiler fuel. A part is also sold to third party, who recovers oil from spentcoffee waste. The next is the sludge from the effluent treatment plant. Other solid wastes are ofsmall quantity. Various kinds of solid waste generated in the factory and their disposal practicesare summarized in Table 6.10. No substantial amount of scrap or waste was found in the factorypremises. The waste management practices are found satisfactory.

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Table 6.10 Solid Waste Generated in HLL, Mysore Plant

S1. Source of Waste Quantity Composition Disposal RouteNo. (tpa)

1 Spent Coffee Waste 4,600 70-80% moisture Sent to Hosur plant(agricultural product) as boiler fuel. Also

sold to third party

2 ETP Sludge 640 20-30% moisture, Given to farmers asrest sludge solids manure (free of

charge)

3 Packaging Material Waste 10 Torn bags, torn Sold as Scraplaminates, etc.

4 Steel, Scrap 21 Scrap pipeline, Sold as Scrapvessels, structure, etc.

5 Wooden Scrap 10 Waste packing, Sold as Scrapdamaged pallets

6 Lube Oil 6 Waste oil from D.G. Sold as Scrappumps

7 Glassware from 0.03 Used glassware Sold as ScrapLaboratory

No hazardous waste is generated from the process. The major waste that is spent coffee waste isused mainly as boiler fuel. The ETP sludge is also used as organic manure. Thus the wastemanagement practice is considered satisfactory.

a

HINDUSTAN LEVER LIMITED, MYSOREPROCESS FLOW DIAGRAM — EFFLUENT TREATMENT PLANT

Raw Effluent I Stage ClarifierCollection Tank 95 KL (D-8.8 Final Polishing— 32KLX2 I M.H.-2.1 M) Pond 836 KL

I SLUDGE

S Screen II Stage Aerator 2x7.5FJP384 KL Aerato s Treated Effluent

to Garden

Raw Effluent II Stage ClarifierCollection Tank 95 KL (D-8.8— 32KLX2 I M.H-2.1 M)

Effluent Filter Press Cap —Holding Tank — Effluent 5K1/H65% solid32KLX3 Collection Pond

500 KL

ReactionTank —32KLX3 Urea Flash Mixer lAlum

0.5 KL

OVERTI Stage Clariflocculator F. ZAerator I 50 KL (D-4.9 m2025 KL H — 3M)

3x25HP 70% UNDER FLOWAerators

* 30%DRY BEDS

l Ox 120KL Capacity

MLSS MAINTAINED IN 1 ST STAGE AERATOR : 2500-3000 ppmF/M RATIO : 0.05 TO 0.15

Dry

Fig-6.1

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7.0 COFFEE CURING UNIT - MYSORE COFFEE CURING WORKS ATCHIKMAGALUR, KARNATAKA

7.1 General

In coffee curing works, the husk or parchment is removed from coffee beans. Then they aregraded, sorted and packed. Coffee from each producer are often separately processed in curingworks. Later similar grades are mixed together. These are then packed in bags andsold/dispatched.

Mysore Coffee Curing Works, modernised a few years ago, has a large capacity of 10,000 TPA.The capacity utilisation was 7283 T in 1996-97 and 7889 T in 1997-98. The works is situatedjust outside Chikmagalur town in Kadur-Mangalore Road. The plant operates for about 8 monthsa year.

7.2 Manufacturing Process

Dried coffee beans, brought to the works in bags are fed to the raw coffee bin. The materialhandling is by pneumatic means. The works is a tall building with 4-5 floors. The material(coffee beans) moves from one unit to another by gravity, unless lifted pneumatically.

From the raw coffee bins, the coffee beans pass to precleaner and destoner which contain sieveswith electrically operated shakers to remove sticks, stones, etc. It then passes through magneticseparator to pick up nails, pieces of iron, etc. The cleaned coffee beans are then hulled. Hulling ismeant to break open the husk or parchment and separate them from the bean. This is done inpeelers by friction breaking followed by forced air (aspiration system) to carry away parchmentpieces and dust.

The hulled coffee is then sent to polisher. Polisher is used to remove the silver skin from washedcoffee. Polisher is not required for cherry (unwashed) coffee.

Green coffee seeds, as they come out of the huller is an assorted lot with seeds of different sizes,shapes, impurities and in perfections. Therefore they are to be graded before marketing. Sizeseparation is carried out by the use of screens of different size apertures with vibrating flat bedtype shaker sieves.

After grader, the beans were earlier sorted out manually by handpicking (called garbling). Forseveral years now, the unit uses a 39 channel fiber optic colour sorter to grade the beansaccording to colour. Bluish green coloured bean is the most desirable according to cupcharacteristics.

Final products, i.e. cured coffee from each producer are separately processed in the curing works.Similar grades are then mixed together (bulking). After bulking different grades are packedseparately in bags.

32

7.3 Genesis of Pollution and Identification of Pollutants

Since the entire process is dry, there is no water pollution. Air pollution is caused during huskhandling. At present the husk is discharged just outside the plant building in to the open (Photo5). The husk could be stored in silo type storage facility with unloading chute loading directlyonto trucks for transporting away.

The plant uses a 224 KVA DG set as standby power service, which is fitted with a stack.

Noise is generated in shaking/vibrating sieves and pneumatic handling equipments. The consentorder issued by the KSPCB stipulates that the noise generated in the factory shall be within theprescribed limits of 75 dB (A) Leq during day time and 70 dB (A) Leq during night time. Theobserved day time noise levels are generally found within the stipulated limits. Outside the plantbuilding no appreciable noise was felt.

7.4 Material & Energy Balance

In the curing process, husk/parchment is separated. Only a small portion of dust/stones/sticksupto 1% is lost as impurities.

Raw Green Beans I Precleaner I Clean G.B Hulling/ I Cured BeansPolishing

Sticks, Stones, etc. Husk@1%

Table 7.1

Sl. No. Tonne of Clean Green Bean Husk Generated( kg)

1 Arabica Parchment 2252 Arabica Cherry 9043 Robusta Cherry 9624 Robusta Parchment 194

The overall energy allocation in the plant is shown in Table 7.2.

The load of the new plant, old plant is 388.83 kW. Assuming the plant runs on an average of 16h/day for 8 month annual consumption is 1.5 million kWh, which brings processing energy perton of product at 190 kWh or say, 200 kWh including lighting load.

33

Photo 5 : Discharge of Husk: Mysore Coffee Curing Works

Table 7.2 Overall Energy Allocation

Si. No. Plant/Unit HP kW1 New Plant 452.45 339.332 Copper Sulphate Plant 8.00 6.003 Old Plant 66.00 49.504 Pump House 30.00 22.505 Lighting 50.00 37.50

Total Load 606.45 454.83

7.5 Waste Management Practices

The main waste is husk. Cherry husk is often used for fuel briquetting. Sometimes the companyuses the husk for captive power generation in its Copper Sulphate plant. Robusta cherry andArabica cherry can be used either for fuel briquetting and is sold @ Rs. 250 per tonne.Parchment husk cannot be used for fuel briquetting but it is usually sold @ Rs. 150 per tonne.Thus the entire waste is reused.

Other wastes include stones/sticks etc. which are buried/taken out of plant. Unusable gunny bagsare also sold. These are, however, insignificant.

During in-depth study no appreciable quantity of waste was noted. The plant was found to bereasonably clean and housekeeping practices were found to be satisfactory. However, the huskstorage needed improvement either by putting up a closed room or a silo type arrangement

9M

8.0 IN-DEPTH STUDY IN LARGE COFFEE PLANTATIONS

8.1 Tata Coffee Ltd., Nullore Division Pollibeta, District Kodagu

8.1.1 General

Tata Coffee Ltd. has several large coffee estates of which Nullore is an important estate. It has390.6 ha under Arabica and 80.9 ha under Robusta plantation. The approximate productions ofclean beans are : Arabica - 485 tons and Robusta - 53 tons in the year 2000-01. Irrigation isobtained from several tanks within the estate.

8.1.2 General Description of Process & Treatment of Wastewater

Nullore estate uses dry process for 110 tons (about 20%) of their harvest. Balance 80% i.e. 430tons is subjected to wet processing. This is done during end November to mid March, i.e. thecrop harvest season.

For wet processing, Pulper and Aquawasher is used. The aquawasher needs about 12.6 kl ofwater for Arabica and 14.4 kl of water for Robusta per tonne of clean beans. On an average 88 to90 kl of water per day is required. Pulping goes on for about 60 days usually in the afternoon /evening (4=30 to 10=30 p.m.) After processing and drying the clean beans (called ParchmentCoffee beans) are transported to curing works (not in the estate).

This estate has two pulphouses served by two ETPs. Each of the ETPs comprises three earthentanks in series. Effluent from one is treated conventionally i.e. neutralization (by lime addition)-anaerobic-aerobic ponds; other is treated with enzyme without neutralization. The tanks in theETP with enzyme treatment are lined with polythene sheets. The ETP with conventionaltreatment has no lining. No details about the enzyme or its dosages were disclosed by the Estate.It was indicated that the enzyme was a combination of pectinase and other enzymes tobreakdown lignin, cellulose and lipids (no action on polyphenols). The raw wastewater andtreated effluents were monitored. On the day of monitoring, there was no effluent overflow. Theeffluent goes down an earthen drain and reported to be used for irrigation.

Results of Monitoring

The results of monitoring of quality of treated wastewater carried out during in-depth study aregiven in Table 8.1 for both kinds of treatment practiced in the estate.

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Table 8.1 Quality of Treated Wastewater, Nullore Estate (in mg/l except pH)

S. No. Parameter Enzyme treatedSecond Tank

Enzyme treatedFinal Tank

Final Tank ofConventionalETP

1 pH 5.8 8.1 5.92 BOD (3 days, 27°C) 6600 5 57003 COD 12400 56 106404 Suspended Solids 688 14 4925 Dissolved Solids 6056 1328 65446 Sulphate 220 43 2567 Oil & Grease N.D. N.D. N.D.8 Ammonia N 97 N.D. 1409 Nitrate N.D. N.D. N.D.

It is noted that conventional treatment does not render the wastewater of desired quality at all.BOD is too high, signifying that the process is not at all effective. On the contrary, the treatmentgiven with enzyme produces effluent of very good quality, which has not been experienced orreported from any other estate .

8.2 Tata Coffee Ltd., Hope Division - Woshally Estate District Kodagu

8.2.1 General

This estate grows mostly Robusta in an area of about 198 ha. During harvesting and pulping,clean coffee @ 4 to 5 tons per day is produced.

8.2.2 Wastewater Treatment

The requirement of water for pulping varies from 14000 to 16000 litres per ton of clean bean. Ina particular season, 200 tons are pulped in about 60 to 70 days. The wastewater is given similartreatment with enzyme and retained in a series of three tanks. During in-depth study, pulping wasin progress. Raw wastewater quality was monitored (before addition of enzyme); enzyme wasbeing added from a jerrican in drops onto the raw water channel leading to the earthen tanks. Thefinal tank was getting filled up. The results of monitoring are given in Table 8.2

Table 8.2 Quality of Treated Wastewater, Woshally Estate (in mg/l except pH)

S. No. Parameter Raw Wastewater(Before enzyme addition)

Enzyme treated FinalTank

1 pH 6.2 5.52 BOD (3 days, 27°C) 28000 120003 COD 64400 180004 Suspended Solids 15120 5005 Dissolved Solids 32096 55126 Sulphate 152 48

S. No. Parameter Raw Wastewater(Before enzyme addition)

Enzyme treated FinalTank

7 Oil & Grease N.D. N.D.8 Ammonia N 132 104.9 Nitrate N.D. N.D.

8.3 Consolidated Coffee Ltd., Karadibetta Estate, Rayarakoppalu, District Hassan

8.3.1 General

Consolidated Coffee Ltd. (CCL) is known to be the biggest coffee plantation in corporate sectorhaving about 4850 ha of coffee plantation. Karadibetta estate has about 381 ha under coffeeplantation of which about 127 ha is under Arabica Plantation and 254 ha under Robustaplantation. The approximate production is about 350 tonne of clean beans p. a. Approximatelyone-third of the crop is unirrigated. Irrigation water is obtained from about a dozen open tanks inthe estate.

CCL uses various inorganic fertilizers such as Factamphos, Urea, Muriate of Potash (K2SO4) andRock Phosphate.

During the in-depth study, CCL mentioned that they use mostly fungicidal sprays (Bourdeauxmixture 1%) @ 25 kg/ha for Arabica only. Other fungicides are also used.

8.3.2 Manufacturing Process

CCL, Karadibetta uses dry process for 40% of their harvest. Balance 60% is subjected to wetprocessing. This is done during end November to mid March, i.e. the crop harvest season.

For wet processing, Pulper and Aquawasher is used. The aquawasher needs about 10-12 kl ofwater per tonne of clean beans. On an average 25 to 30 kl of water per day is required. Afterprocessing and drying the clean beans (called Parchment Coffee beans) are transported to curingworks (not in the estate).

The wastewater from Pulper-Aquawasher is taken to the Effluent Treatment Plant by gravity.The wastewater is first neutralized in a neutralization tank (6m x 6m x 1.2m) where lime isapplied. (The nutrients are also added in the neutralization pit but details were not madeavailable.) From the neutralization tank the wastewater is led into an Anaerobic lagoon (19m x8m x 3.3m deep) which is understood to have a detention time of nearly 20 days. From anaerobiclagoon, the wastewater flows to an aerobic lagoon of size 17.7m x 11.6m x 1.2m deep fromwhere it goes to an unlined tank. Photo 6 shows a general view of the ETP.

8.3.3 Genesis of Pollution & Identification of Pollutants

As mentioned earlier, during wet processing, the outer skins and fleshy pulps are separated andmixed with water. Apart from soluble and suspended matters, fruit skins and settlable matter arealso present in the wastewater. These can be removed by settling.

37

Photo 6: General View of Effluent Treatment Plant, CCL

The wastewater is high in organic content, low in pH and substantial dissolved solids. Thecharacteristics of raw wastewater from CCL, Karadibetta and other plantations nearby are shownin Table 8.3

Table 8.3 Characteristics of Raw Wastewater from Wet Process ETP

Si. No. Plantation/ Estate pH BOD COD SS TDS

1 CCL, Karadibetta 5.0 28,000 - 596 -

2 Karadikhan Estate 3.2 930 2,360 236 1,9463 Manjunath Estate 3.2 15,600 26,400 1,624 5,6184 Hoshally Estate

(Coffeelands Ltd). 3.4 31,000 51,208 1,496 3,288

The BOD/COD ratio is in the range 42.6% - 60.5% indicating that the wastewater is amenable tobiological treatment.

The anaerobic-aerobic two-stage treatment given to this wastewater after neutralization andnutrient addition does not yield wastewater of desired quality. This is evident from the Table 8.4.

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Table 8.4 Characteristics of Treated Effluent from Plantations/Estates Using Two-StageTreatment

SI. No. Plantation/ Estate PH BOD COD SS TDS

1 CCL, Karadibetta 3.9 10,500 - 348 -

2 Karadikhan Estate 4.3 480 1,392 64 1,8163 Harley Estate, 4.3 2,250 4,993 110 1,918

Sakleshpur4 Sulugodu Estate Alur 4.7 1,860 4,533 192 3,940taluk

Standard of KSPCB 6,0 to 9.0 100 - 200 -

8.3.4 Material & Water Balance

Fruits are the raw materials and (clean) green beans are the finished product in theplantation/estate. During wet processing, only water is added. Typical figures obtained during in-depth studies are shown in Table 8.5.

Table 8.5 Material Balance in Production of Beans from Fruits

VarietyFruit I Dry Parchment

Clean Coffee(Figures in Kg)

Arabica 5500 1225 1000Robusta 4700 I 1200 1000

Roughly therefore 78% by weight of Arabica and 74% by weight of Robusta fruits are removedin wet process. However a considerable part of it is lost as moisture because dry parchmentcontains about 12% moisture.

Generation of wastewater by wet process is reported to be 80 kl per tonne of clean beans (CCRI,1996-97) whereas CCL, Karadibetta has reported wastewater generation @ 10-12 kl per tonne ofclean coffee because CCL uses high proportion of recycled water in the aqua pulper. This lowwater usage could be the reason for very high BOD of raw wastewater.

8.4 Conclusion

From the above it appears that the quality of treated wastewater is far from the desired one. Thisis despite the fact that the 'enzyme' is being added. When compared to the quality of similarlytreated wastewater in Nullore Estate of the same owners, it is not clear why there is such a widevariance ( BOD varying from 5 mg/I to 12000 mg/1). No firm conclusion can be drawn about theeffectiveness of enzyme treatment from these two estates, who did not divulge details about theenzyme, dosage and performance However, it is abundantly clear that the present method oftreatment (recommended by KSPCB as per old NEERI study) practiced by the large estates isnot at all satisfactory to render the quality suitable for irrigation according to the existingstandards.

39

9.0 POLLUTION CONTROL IN COFFEE PROCESSING

General

The pollution problem in coffee plantation and coffee processing industries have been studiedthoroughly and its status is summarized as below:

A. Instant Coffee manufacturing result in water pollution and therefore deserve attention.B. Wet processing of coffee fruits in manufacturing of parchament coffee result in water

pollution and therefore deserve attention.C. Dry processing of coffee is carried out by the farmers usually in small scale. Air pollution

is negligible.D. Coffee curing is a dry process and no water is used in the process. Air pollution may be

caused by (i) Fuel burning for energy production (as stand-by source of electricity ingeneral) and (ii) Emission of dust due to huller operation and use of air aspiration. Thestack emission is usually controlled. Husk generated as solid waste is reused completely.

9.1 Instant Coffee Manufacturing plant

9.1.1 Wastewater Treatment Practices

1. The wastewater treatment in HLL is carried out by aerobic biological treatment followed bychemical treatment to reduce colour (Tertiary treatment).

2. Asian Coffee Ltd. (Production 2000 tonnes; annual turnover : Rs. 54 crores) located inMedak District, Andhra Pradesh uses the following process:

- pH correction- Chemical precipitation- High Rate Anaerobic Filtration- Activated Sludge Extended Aeration

By this process ACL is able to bring down the raw wastewater characteristics of BOD:2180,COD:4160, pH:5.45, O&G:28.0, Total Solids:3880 to BOD:100, O&G<10.0 and TSS:2000mg/l. The wastewater is required to be discharged on land for irrigation as per the consentorder of APPCB.

3. Nestle India Ltd. reported that they use Activated Sludge Process, but no details wereavailable. Their stipulated standard of treatment is BOD<30.0, COD<250.0 and SS<150.0 fortheir plant at Nanjangud, Mysore.

Apart from the use of (a) Two stage aerobic biological treatment and (b) Anaerobicfilterfollowed by extended aeration, and other processes have also been tried. Upflow AnaerobicSludge Blanket (UASB) Process is often used. However, reports of the treatment of instantcoffee wastewater in UASBs are conflicting. While some report successful full scale mesophilicoperation, others reported failure in operation beyond 50 days, resulting in rise in Total Volatile

Fatty Acids (TVFA) (Lanting, 1989). A study by Dinsdale et. al. (1997) examined operation ofUASB in the thermophilic operation. The wastewater characteristics are shown in Table 9.1.

In the aforementioned study, Nitrogen and Phosphorus (as urea and DAP) were added to give aCOD: N: P ratio of 400:7:1. Seed was taken from a pilot plant UASB operating mesophilicallyon instant coffee wastewater at the Nestle Instant Coffee Factory, Hayes, London, U. K. It wasfound that both mesophilic and thermophilic UASBs could be operated with low TVFA andgood COD removal. The mesophilic reactor achieved a marginally better effluent quality withaverage COD removal of 76% and TVFA of 25 mg/l compared to 70% COD removal and 100mg/l TVFA level in the thermophilic conditions. The maximum sustainable Organic LeadingRate was 10 kg COD/cum./day on the basis of settled wastewater and after nutrient addition.

Table 9.1 Characteristics of Raw Settled Coffee Waste for Treatment by USAB Process(after Dinsdale)

Analysis Range of Values

Total Solids ( /l) 10.4 — 13.2 (3)Volatile Solids (g/1) 10.4 — 13.0 (2)Suspended Solids (g/1) 0.6 — 1.0 (2)Total COD (mg 02/1) 7400 — 18,000 (15)Total Lipids (g/1) 1.5 (1)Calcium (mg/1) 70 — 90 (2)Potassium (mg/1) 90 — 110 (2)PH 4.1-4.6(5)0== Number of separate samples taken from the effluent stream for analysis.

Since BOD reduction has not been reported, it is unclear what was the order of reduction.However, as is common with characteristics of UASB reactors, further treatment would berequired to bring down the effluent to stipulated level of 100 mg/1 BOD, as well as removal ofcolour.

The typical characteristics of raw wastewater of three major manufacturers of instant coffee inIndia are shown in Table 9.2. It appears that there is substantial variation in the characteristics.One of the reason is that HLL uses chicory roots which has more carbonaceous matter. The otherreason is very limited data. Only typical values are indicated for Nestle and Asian while HLLfigures are based on geometric mean of three sets of data.

Table 9.2 Typical Characteristics of Raw Wastewater of Major Manufacturers of InstantCoffee

Sl.No

Manufacturers CharacteristicsH BOD COD SS DS Cl" SO42

1. HLL, Mysore 5.60 1022 5162 402 815 56 902. Nestle, Nanjangud,

Mysore 5.60 510 1346 210 1195 10 29

3. Asian Coffee, A. P. 5.45 2180 4160 640 3240 71 290

41

The treated effluent characteristics are shown for these plants in Table 9.3.

The cost of treatment related to the turnover is Rs. 747.8 per ton by ACL, whereas the same forHLL is Rs. 1160/- per ton. However the percentage of cost of treatment related to overallproduction cost to ACL is 0.16% whereas the same for HLL is 0.26%. These percentages areconsidered to be reasonable considering this is an agro-based industry.

Table 9.3 Characteristics of Treated Effluents of Major Instant Coffee Manufacturers

Sl. Manufac- CharacteristicspH BOD COD SS TDS Cl" SOaNo Treatment details

turers

1. HLL, 1.Aerobic 6.6 11.6 177.5 55.6 996.4 98.1 224.9Mysore biological

treatment2. Chemical

treatment to reducecolour

2. Nestle, Activated SludgeNanjangud Process 8 0 6.7 182.0 36.2 667.8 180.5 72.4

3. Asian 1. pH correctionCoffee, 2. ChemicalA.P. precipitation

3. High ratAnaerobic 9 0 100.0 - 2000 - - -

Filtration4. Activated Sludg

ExtendedAeration

Notes: (a) SI. No. 1 data based on geom. mean of 7 sets of data.(b) Si. No. 2 data based on geom. mean of 6 sets of data.

It is clear that the current practice of wastewater treatment in India is satisfactory and the costassociated with it is reasonable. Consequently the existing standards are achievable withreasonable technical and financial input.

9.1.2. Air Pollution and its Control

During processing, appreciable dust is generated. To control the air pollution, air pollutioncontrol devices i.e. catalytic converter, cyclone & multi-cyclone are installed depending upon thesuitability of particular device

Fuel oil & HSD are used as an energy source, which gives rise to air pollution in the form ofSPM, SO2 and NOR . The relevant standards of emission & chimney heights are applicable whichare followed by the industries.

42

9.2 Coffee Plantations - Wet Processing (Parchament Coffee)

Preparation of washed coffee requires pulping and washing equipment and substantial quantityof clean water. The approximate water requirement for production of one tonne of clean coffee is80,000 1 for Arabica & 93,000 1 for Robusta while using conventional pulper & washers. Thecoffee effluents are acidic, containing high amounts of suspended and dissolved organic solids,effluent BOD ranges from 2,500 to 12,000 mg/l. To reduce water consumption, wash water isrecycled in aqua pulpers.

State Pollution Control Boards (SPCBs), apply general standard for discharge of wastewater tocontain the pollution of perennial water sources in accordance with the Water (Prevention &Control of Pollution) Act (1974). The coffee processing industries are required to obtainpermission from SPCBs for wet processing of coffee by giving an undertaking that the effluentswill be treated to the standards prescribed, or stored within their premises. As already mentioned,such standards are not quite achieved particularly in case of wastewater of high BOD.

9.2.1 Wastewater Treatment Method

The various studies conducted at the CCRI (Central Coffee Research Institute) in collaborationwith the National Environmental Engineering Research Institute (NERRI), Nagpur from 1978 to1980, have shown that biological methods involving anaerobic digestion followed by aerobiclagooning were suitable to treat the high strength organic wastes. After removing the coffee pulpusing an appropriate screen (8 mm dia), wastewater from different sections is diverted to anequalization tank 9since effluent of different strength are produced in different sections, likepulping washing etc., so there is a need to equalize the effluent of various strength at varioussections). The equalization tank is generally built of brick masonry with acid proof cement withsuitable arrangement of water tightness, the suspended solid settles at the bottom so properarrangement of the de-sludging has to be made. The detention time is usually kept as 1 day. ThepH of wastewater needs to be corrected to 6.5 to 8.0 before it enters into the anaerobic lagoon.Generally, the wastewater is deficient in Nutrients, primarily Nitrogen. For sustainability &efficiency of the biological processes the BOD:N:P should be 100:2.5:0.5. In case of nutrientdeficiency, additives like urea for Nitrogen & Phosphoric acid for Phosphorous are to be addedinto wastewater to match the desired ratio.

Wastewater is neutralized by addition of lime dose @ 250 mg/1. the effluent from equalizationtank is fed to anaerobic lagoon, the detention period of 8 days. The effluent from the anaerobiclagoon is led to Activated Sludge Process and extended aeration system. The under flow from thesludge drying beds can be mixed with final effluent also. To maintain the required mixed liquorsuspended solid about 4000 mg/1 in the aeration system, part of the sludge from the secondarysettling tank is recirculated into the ditch.

The effluent from the extended aeration activated sludge unit is led to a secondary settling tankfor sludge separation and disposal. The supernatant from the clarifier shall be disposed off intothe nearby river body, provided the effluent standards for disposal (BOD max = 30 mg/1) isachieved. If the desired effluent standard for disposal into river body is not achieved, then some

43

other alternatives i.e. anaerobic lagoon followed by aerated lagoon & finally polishing pond oranaerobic filters (double stage) followed by polishing pond may be deployed.

The filtrate form the sludge drying beds can be led back to aeration tank or can be disposed offalong with final effluent. The system flow diagram is presented in Fig 9.1. The dried sludge canbe used for agricultural purposes or can be disposed off by incineration (the former beingpreferred).

9.2.2 Wastewater Treatment Methods Used in other Countries

In many coffee producing countries, both aquapulper and fermentation are used. The sources ofwastewater generation are as under :

Pulping WasteBeanwash after pulperFermentation tank

Typical characteristics of wastewater are given in Table 9.4.

Two types of treatment schemes have been employed. (i) The first is Anaerobic Lagoon/ Filterfollowed by Diffused Aeration (Fig. 9.2). In this scheme, 95 — 96 % BOD reduction is reportedto be achieved. This means that at the higher end of wastewater strength (BOD being in the orderof 8,000 mg/1), typical treated effluent BOD would be about 400 mg/l, which would still needtreatment, before being used for irrigation.

Table 9.4 Typical Characteristics of Raw Wastewater in Coffee Wet Processing

Si. No. Parameters Range (mg/1)

1 Colour Brown2 PH 3.5-4.63 COD 15,000 — 30,0004 BOD 5,000-8,0005 TSS 5,000 — 8,0006 Total Solids 20,000 — 30,000

(ii) The second scheme of treatment (Fig. 9.3) substitutes a Trickling Filter in place of AerationTank, other unit operations/processes remaining the same. The efficiency goes down to 80 — 85% removal of BOD/COD. This means that the treatment would not yield the desired quality ofeffluent. With influent BOD of 5,000 mg/l, the finally treated effluent would have BOD 750mg/l. Further treatment would be required to bring down the BOD and COD level of effluent.

In Costa Rica, UASB process has been used in San Juanillo Coffee Mill. The flue gas fromburning of biogas is used for drying coffee. The salient features reported are shown in Table9.5.

Table 9.5 Aspects of UASB Treatment Plant for San Juanillo Coffee Mill, Costa Rica

SI. No. Aspect Value

1 Capacity of WTP 4,000 Kg COD / day500 cum./ day @ 8 Kg COD/cum.

2 Treatment Efficiency 80% COD removal3 Biogas generated (max) 1000 cum. / day4 Substituted lumber 150 cum. per season

It has been reported that the treatment plant cost is US $ 113,776 to set up which is equivalent toUS $ 228 per cum. per day or Rs.11,000 per cum. per day. The quality of treated wastewater isnot reported; however, it can be derived to be 1600 mg/l of COD and perhaps 500 to 600 mg/l ofBOD. The operating cost has been reported to be US $ 2 per tonne of berries. Considering US $500 per tonne of berries (fruits), the percentage cost of treatment with respect to product is 0.4%. This percentage would increase, if add-on treatment is considered. Such details have not beenreported in case of San Juanillo plant.

9.3. Pollution Issues and its Control in Coffee Curing Works

In coffee curing, entire process is dry and as such there is no water pollution. Air pollution iscaused by fuel burning in the D.G. set used as standby power source. The stack heights arestipulated by the concerned SPCB, which are followed by the industries. No hazardous materialsare used. Noise pollution is generally within the stipulated limits. The only solid waste producedis husk, which is reused anyway.

9.4 Suggested Method of Treatment of Wastewater

It is seen from the foregoing paragraph that the existing methods of treatment are not adequate somuch so that the desired quality of effluent is achieved. One of the reason is that the wastewateris fairly strong; other reason is inadequacy of treatment units. It may be noted, however, that thewastewater is amenable to biological treatment after addition of nutrients.Quantity of Wastewater generation :Small farms with cultivated area of less than 4 ha each constitute the largest cultivation i.e., morethan 93.4% of national total. However, they mostly use dry processing. Even if some of them usewet processing, the resultant quantity of wastewater would be very small:

Average production of beans per ha = 867 kg ('98-'99)Total production for 4 ha = 867 x 4 = 3468 kgWastewater generated @ 80 litre/kg = 277 kl

Assuming that this wastewater is produced in 100 to120 days, wastewater generated = 2.3 kld.

On similar basis, wastewater generated for medium plantations (more than 4 ha and upto 10 ha),would be about 5.9 kid. It is to be noted that wet processing is a batch process and therefore thedaily discharge can vary widely. Furthermore, the number of days of operation may be evenlesser. On the other hand, by using recirculation of water in aquapulper, actual wastewatergeneration may be considerably less than the often used figure of 80 litre per kg of clean bean.

For large plantations, the area under cultivation varies widely. Furthermore water use variessubstantially. Some use recycling of water thereby reducing the water use. This makes thewastewater quite strong and difficult to bring down the BOD/COD to acceptable limit. Othersmay use more water to make the raw wastewater easier to treat. To illustrate this point, twoexamples can be considered from the data gathered.

(i) In Karadibetta estate (381 ha cultivated area)

Total annual production = 350 T of clean beanWet processing done for 60% = 210 T of clean bean

Water consumption in aquawasher@ 12 kl/T of bean =2520k1

Wastewater generation is reported as 20 to 24 kld

No. of days ETP is used = 126 to 105 days

(ii) In Kolarkhan estate, Sangameshwar, (175 ha)

Total annual Production = 300 - 400 T fruits = 72 to 96 T green beans

Wastewater generated is reported to be 160 kld

If 100 days working is assumed,

Water consumption = 160x100/84 = 1901/kg of bean

This figure is high so there is a possibility that fresh water may be mixed to dilute treatedwastewater.Quality of Raw WastewaterAs mentioned in the foregoing, the quality of raw wastewater is dependent on water use andtherefore the variation is quite large. However, a typical case may be considered:

Area under cultivation = 200 haProduction of beans @867 kg/ha =173.4 TWastewater 80 1/kg = 13872 klWastewater/day @ 120 days = 13872/120 = 115.6 kld

A typical flow rate of 100 kld would be reasonable. Figures for generation of BOD per unit

weight of beans are not readily available.

46

Internationally, a range of 5000 to 8000 mg/1 of BOD is reported. In previous studies by NEERI,a BOD range of 3000-4000 mg/l was used. With recycling in place it is considered that a figureof 6500 mg/1 for BOD should be a reasonable average.The alternative treatment schemes have been conceived with the following raw wastewaterquality:Color & Odour Brown Coffee like Color and Pungent Coffee OdorpH - Acidic (pH range between 3.5 - 4.6)COD - 25,000 mg/1BOD - 6500 mg/lTSS - 5000 mg/1T. Solids - 25,000 mg/1

The major constraints to be considered in deciding the treatment technology are:

• That the coffee processing is a seasonal industry operating for 120 to 180 days per year,• It is a batch process resulting in release of wastewater in batches

Therefore the treatment scheme that is adopted should be one which must have a wasteequalization facility and the process units be such that:- have the ability to accept shock loads

the startup period is short .be based on a technology that requires minimal •operator attention

Considering the above constraints the following basic schemes / technology options have beenstudied. All the process options would essentially involve primary treatment comprisingscreening, equalization and pH correction. The latter is required to adjust the pH as the coffeewaste has low pH (about 3 to 5) and need to be adjusted prior to any form of biologicaltreatment. Equalization will depend upon the capacity of the wastewater generated.

9.4.1 Treatment objectives

By and large, the treated wastewater is used for irrigation in coffee plantations both in India aswell as in other coffee growing countries. In India, despite the enforcement standards of wateract by the SPCBs, the compliance is far from satisfactory. Judging by the data gathered, it is seenthat wastewater is strong and it is quite difficult to bring down the BOD to less than 100 mg/lresorting to tertiary treatment.

For this study, two approaches have been considered:

Approach A : Secondary biological with an objective to bring down the BOD to less than 500mg/1

Approach B : Secondary biological treatment followed by tertiary treatment to bring down theBOD to less than 100 mg/1

These two approaches have been considered keeping in view the treatment adopted in othercountries and techno-economic viability or achievability of treatment objectives.

47

The conceptual treatment schemes for Approach A are described below:1) Treatment Scheme —I

This scheme comprises the following units (Refer Fig 9.4 for the diagram)

a) Screening, equalization, waste transfer by pumping, pH adjustment. Recommendedequalization is of 24 hour.

b) Anaerobic lagoons — bulk volume type with a HRT of about 30 days.

c) Bulk Volume Aerated Reactor - Aerated Lagoon with floating surface aerators operatedon low MLSS and F/M ratio.

d) Settling Pond cum polishing pond a gravity settling pond with facility of storage ofsludge for one season.

The removal efficiency and the expected waste water quality after each stage of treatment isshown in Table 9.6.

Table 9.6 Treatment Scheme - I: Process Efficiency

Parameter(mg/I)

InletCone

After Anaerobic Lagoon After Aerated Lagoon /StabPond

Removal Concentration % Removal Concentration

BOD 6500 70 to 75 1600 -2000 75 to 80 300 to 500

COD 25000 65 to 70 8 to 10,000 60-65 3000 -4000

TSS 5000 75 to 80 1000-1250 85 to 90 200 to 250

This option would require a relatively a large area for treatment.

Advantages:

— Low expertise in operation— As the process is based on Bulk Volume reactors — large volumes ensure that stabilization

and start up vis a vis filling of reactors is commensurate with each other i.e. by the time thereactors are filled, the waste water will be achieving a desired water quality.

— The water stored in the reactors can be utilized as irrigation water in dry season.

2) Treatment Scheme —II

This schemes comprises the following units: (Refer Fig 9.5 for flow diagram)

a) Screening, equalization, waste transfer by pumping, pH adjustment.

48

b) Bulk Volume Anaerobic bio Reactor with covered floating Polythene roof with bio gasrecovery, storage and utilization.

c) Bulk Volume Aerated Reactor - Aerated Lagoon with floating surface aerators operatedon low MLSS and F/M ratio.

d) Settling Pond cum polishing pond and gravity settling pond with facility of storage ofsludge for one season.

The removal efficiency and the expected waste water quality after each stage of treatment isshown in Table 9.7.

Table 9.7 Treatment Scheme - II: Process Efficiency

Parameter(mg/l)

InletCone

After BV Anaer. Reactor After Aerated Lagoon /Stab Pond% Removal Concentration % Removal Concentration

BOD 6500 80 to 85 1000-1300 75 to 80 300 to 400

COD 25000 75 to 80 5000-6000 60-65 2000-2400

TSS 5000 75 to 80 1000-1250 85 to 90 200 to 250

Advantages:

— Energy positive — possible to recover energy about 25 to 30 litres of bio gas having a energypotential of 24 to 28 kW per kg of berry processed of which about 30 % is recoverable inform of electric energy.

— Due to its large volume the bulk volume bio-reactor (anaerobic reactor) can take shock loadswithout effecting the performance.

— As the second stage of the treatment is based on Bulk Volume Aerobic reactors, largevolumes ensure that stabilization and start up vis-a-vis filling of reactors is commensuratewith each other i.e. by the time the reactors are filled the waste water will be achieving adesired water quality.

— The water stored in the reactors can be utilized as irrigation water in dry season.

Disadvantages

— Higher capital cost due to membrane cover.

— Bio Gas generation & handling requires proper safety measures.

3) Treatment Scheme —III

This schemes comprises the following units (Refer Fig 9.6 for flow diagram)

a) Screening, equalization, waste transfer by pumping, pH adjustment.

b) Enhanced High Rate Physico Chemical Treatment (PCT) to remove the colloidal andsupra colloidal organics — using chemicals basically Poly Aluminum Chloride (PAC) &polyelectrolyte and clarification using a high rate, clarification system such as TPI orDAF. Removal BOD and COD is excepted in the range of 60 %.

c) Two Stage Activated Sludge — first stage loaded at an organic loading rate of 5-6 kg/m3and operating at MLSS of 6 to 8000 mg/l followed by Second Stage which would beloaded at about 2kg/m3 and operating at MLSS of 4000 mg/l. The overall efficiency ofthe system will be about 90 %.

d) Sludge Dewatering Beds.

The removal efficiency and the expected waste water quality after each stage of treatment isshown in Table 9.8.

Table 9.8 Treatment Scheme - III: Process Efficiency

Parameter(mgn)

InletConc

After PCT After 2 Stage ASP% Removal Concentration % Removal Concentration

BOD 6500 60 to 65 % 2200-2400 90 % 225 to 250

COD 25000 55 to 60 % 10-11,000 75% 2500 to 2700

TSS 5000 98% 100 95% less than 100

Advantages :

— Low land area— PCT ensures more or less instant start up and up to 60 % pollutants removal. The

biological reactor will have a start up of about 2 weeks or so

Disadvantages

— Higher Operating Costs— Higher Sludge Generation; however the sludge can be converted into compost and used.

The comparative costs (capital as well as operation and maintenance) of suggested schemes inApproach A are shown in Table 9.9.

Table 9.9 Comparative Cost of Alternative Treatment Methods (Approach A)

Alt Method Lagoon Capital Cost/m O+M Cost/rri

I a Anaerobic. + aerated lagoon 25,375 25.30+ Stabil pond

I b BV Anaerobic reactor + 60,525 19.90aerated Lagoon + Stabil pond

I c Physico - chemical treatment 34,245 35.30+ 2 stage ASP

Approach B

Treatment of wastewatwer by biological methods such as anaerobic lagoons and aerated lagoonsor any other biological treatment system would be able to bring down the BOD of treatedwastewater to a level of about 500 to 600 mg per litre as described in Approach A. Normally,this level of BOD should be acceptable for reuse in the coffee plantation itself. However, thecurrent standards specify that for discharge of the treated wastewater for use as irrigation waterthe BOD should be less than 100 mg/1 & total dissolved solids less than 2100 mg/l.

In order to reduce the BOD to that level it would be necessary to put in a Physico-chemicalTreatment (PCT). The PCT may involve oxidation of the organic wastewater which basicallycomprises of caffeine, lignin, tannin and alkaloids present in both soluble and supra-colloidalform exhibiting both BOD & COD.

The conceptual treatment scheme proposed for reducing these organic substances by chemicaloxidation is based on use of hydrogen peroxide as the oxidizing agent in presence of Ferrous Ionas a catalyst to oxidize and precipitate the organics (Fenton's Reaction) producing CO2, H2O plusinorganic salts. The extent of oxidation depends upon the amount of H 2O2 used. The theoreticalH2O2 requirement is of the order of 2.1 kg per kg of COD/BOD oxidized. However in manycases complete digestion of the organics to CO2 and water is not required and this would reducethe H202 and other chemical requirements.

The physical separation of BOD/COD with H2O2 may occur in two ways:

➢ Partial oxidation of organic contaminants results in polar (i.e. charged substances) whichare amenable to sorption onto coagulants and flocculants.

➢ Enhanced physical separation by flotation is provided by H202 - which occurs by naturaldecomposition of H2O2 to oxygen & water i.e. H2O2 supersaturates the .wastewater withoxygen which results in the formation of evenly dispersed micro-bubbles which scavengethe organic particles as they rise to the surface.

In the present case as only partial reduction is desired, the dosage of H 2O2 will be limited tophysical separation by adsorption on to flocs of Coagulants/ Flocculants.

51

The dosage of H202 required about 300 to 400 mg/l in presence of Ferrous Ion concentration of35 to 40 mg/l plus a lime dosage of 100 to 120 mg/l and a polyelectrolyte dosage of 1 to 1.5mg/1. These are estimated dosages; the final dosages need to be established after bench scalestudies of the wastewater.

The conceptual scheme would comprise of the following units.

A sump in which the wastewater from the Aerated Lagoons will be collected and then transferredfor tertiary treatment by H20 2 .

The wastewater would be pumped to a reaction tank having an agitator. In this reaction tank,Ferrous Sulphate and Hydrogen Peroxide would be added. The Ferrous Sulphate is only formake-up and for the initial starting of reaction it acts as a catalyst. Hydrogen Peroxide will beconsumed. The pH may drop in the reaction and to adjust the pH it would be necessary toprovide an alkali (such as lime, caustic soda or soda ash) for pH adjustment; a small dose ofpolyelectrolyte (about 1 mg/l or so) would be required.

Clarification of the wastewater in a TPI or a tube settlers is proposed.

The above chemical oxidation of wastewater will be able to reduce colour and BOD and it willensure that the BOD of the treated wastewater is less than 100 mg/l on a consistent basis (Table9.10). For flow sheet, refer Fig 9.7.

Table 9.10 Expected Quality of Treated Wastewater (Approach B)

Scheme Description Quality of Wastewater

BOD mg/1 COD mg/l SS mg/1

II a Anaerobic Lagoon + 90 700 20Aerated Lagoon + PCT &SDB

II b BV Anaerobic Reactor 90 700 20(Covered) + AeratedLagoon + PCT & SDB

II c PCT + Activated Sludge + 90 700 10Chem. Oxidation &Tertiary Filter + SDB

Comparative costs of alternative treatment methods (Approach B) are shown in Table 9.11.

52

Table 9.11 Comparative Cost of Alternative Treatment Methods (Approach B)

Alt Treatment Process Capital Direct Energy O+MCost/m3 Operating Recovery Cost/m3

(Rs.) Cost (Rs.) (Rs.)II a Anaerobic. + aerated 43,351 38.10 0 38.10

lagoon + PCT & SDBII b BV Anaerobic Reactor 78,651 48.30 16.50 31.80

+ Aerated Lagoon +PCD & SDB

II c PCT + Activated 41,305 44.40 0 44.40Sludge + Chem.Oxidation & TertiaryFilter + SDB

A comparison of treatment costs for Approaches A & B is presented in Table 9.12. Whileworking out the annualized cost it is assumed that the interest on capital at the rate of 16% wouldbe applicable for comparison. No repayment of capital has been considered.

Table 9.12 Comparative Cost of Alternative Treatment Methods (Approaches A & B)

TreatmentAlt.

AnnualizedCost/ m3

(Rs.)

0 & M Cost/ m'(Rs.)

Treated Wastewater(BOD/SS)

Ia 4085.30 25.30 450/100lb 9703.90 19.90 450/100Ic 5514.50 35.30 250/100II a 6974.26 38.10 90/20

II b 12615.96 31.80 90/20

II c 6653.20 44.40 90/10

It is seen from the Table 9.12 that the most cost effective alternative would be alternative I awith the quality of treated wastewater as BOD 450 and SS 100. The most cost-effectivealternative for bringing the BOD to less than 100 would be alternative II c. however it wouldnearly double the operating cost. Moreover, the cost of chemicals is expected to rise due to costescalation thereby making it more expensive over a period of time. It is imperative therefore thatthe treatment objective for the immediate future may aim at reducing the BOD to less than 500.Once this is attained, further reduction may be attempted at.

53

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10.0 PROPOSED STANDARDS FOR COFFEE PROCESSINGINDUSTRIES

10.1 General

The existing general standards for discharge of wastewater in water bodies have been reviewedwith respect to each of the three categories of coffee processing industry- (a) the instant coffeemanufacturing (b) Coffee curing and (c) Coffee plantations. The review was based on mainlythree aspects:

• Compliance of existing standards in force

• Cost of achieving the standards

• Technical/ Managerial problems in complying with the standards

In the following paragraphs these are dealt with for each of the three categories.

10.2 Instant Coffee Industry

A review of consent conditions stipulating the standards and compliance records with respect toa few instant coffee producing units show that the industry does not face any serious problem inattaining the stipulated standards with respect to air and water pollution. The results of in-depthstudy clearly indicate that as far as control of air pollution is concerned, the consent conditionsare complied with. These relate mostly to air emissions from the stand by power source (DGsets) and from the processes. The use of stacks of stipulated height for control of SO2 does notwarrant any change. The control of SPM by use of cyclones in the process units as an existingsystem is also fairly satisfactory, economical and attainable. While some SPCB stipulates SPMemission standard as 115 mg/m3 , others use 150 mg/m3 . The ambient air quality standards usedby the SPCBs are as per existing standards under the Air Act and are complied with by theindustries. As far as control of odour (aroma, in this particular case) is concerned, the industryuses catalytic converters for complete oxidation of aromatic compounds.

10.3 Coffee Curing Works

In the coffee curing works, there is only air emission, both from the processes and also from thestacks of DG sets. The existing emission standards as stipulated by the SPCBs require no changei.e. the control of SO2 by stipulated stack height and emission of SPM shall not exceed 150mg/m3, Further more the consent condition requires that there shall be no smell or odournuissance from the industry. These standards and conditions are achieved without any difficultyby the industry.

Furthermore, the noise standards for noise generated with in the factory premises and in ambientshould also remain unaltered.

10.4 Coffee Plantations - Wet Processing

As discussed in detail in section 5 (in-depth studies) the existing standards for quality of treatedwastewater are not met at all. In fact, in most cases, the quality is far from the stipulated BODand SS. This is particularly true for medium and large plantations. The reason is that the

61

wastewater is very strong and the existing method of treatment is completely inadequate. Inalmost all cases the wastewater is used for irrigation in the coffee gardens. The coffee pulping &washing wastewater contains not only high BOD but also colour due to presence of lignin.Removal of these requires expensive secondary and tertiary treatment.

To achieve the existing standards such treatment as given in Approach B would be necessary. Itis doubtful whether such elaborate and expensive treatment would be practicable in coffeeplantations which are located in rural and semi-rural areas. Moreover the treatment plants wouldbe operated only 3-4 months a year. The choice therefore lies between (i) the existing situationwhere effluents containing several thousand mg/l of BOD are discharged and (ii) adopting verysophisticated treatment requiring skillful operation and high cost of treatment. While the formeris not desirable, the latter would be very difficult to achieve.

In view of the above difficulties, it is considered desirable that a step by step approach would bepractical and perhaps acceptable given the constraints. The treatment alternatives suggested inApproach A to bring down the BOD to 500 mg/l and use it for irrigation in the coffee plantationitself, as an interim measure would be feasible. Once this is achieved, further reduction may beconsidered at a later date depending upon the success towards the introduction of a stricterstandard. This interim standard can be introduced considering the special problems of the coffeeplantations. For small plantations, no standard is suggested as the volume of the discharge is verysmall and therefore their impact on soil is considered insignificant. In Kerala, there are largenumber of such small plantations for which the KPCB does not enforce the provisions of theWater act. For such small plantations two alternatives may be considered - (i) solar drying ofeffluents in lined ponds (ii) using the effluent for mixing with compost which would be gainfullyused as organic manure. The sludge can be used for growing mushrooms.

The findings of the in-depth study were deliberated by the Peer & Core committee of the CentralPollution Control Board and the following standards were recommended for notifications:

A. The points of di :•'fissions could be summarized as follows:

(i) Coffee growers with more than 25 ha plantation area could be considered as growers withmedium to large size holdings.

(ii) 98% of the coffee growers have small holdings covering plantation area less than 10 ha.There growers use about 3000 litres of water per day and contributes to less than 20 kgBOD a day.

(iii) Small to medium growers 10-25ha)generates 20-50 kg BOD/day and uses 3000-10000litres of water per day.

(iv) Indian Institute of Science, Bangalore has developed a high rate bio-reactor using methano-bacterial attachment for treating coffee effluent along with production of bio-gas. Bio-reactor shall replace anaerobic lagoon and its area requirement will be equal to 5% ofequivalent anaerobic lagoons. The reactor's efficiency in terms of COD removal will bearound 70%.

62

(v) Educating the planters is the need of the day.

(vi) Modern Aquapulper has reduced the water consumption by one-third. Originally waterusage per ton of coffee bean processes was 80,000 liter for Arabica and 93,000 liter forRobusta in conventional pulpers and its washers.

(vii) The concept of transporting wastewater of coffee plantations from the area of smallgrowers through tankers would not be possible as the plants grow in altitudes i.e. hills.

(viii)The treated wastewater with a BOD more than 100 mg/1 is unsuitable for irrigation. TheBOD and COD values in the untreated coffee effluent are in the ranges of 10,000 — 13,000mg/l and 18,000-23,000 mg/l respectively.

B. The following interim standards were recommended for notification:

(i) The coffee growers of 25 ha and above i.e. large sized holding shall meet a BOD3 27 °Climit of 500 mg/l for their wet coffee processing wastewater within a period of one yearfrom the date of notification of the standards.

In the mean time, the Coffee Board will come up with alternative technologies to cope withthe standard by April 30, 2005. The treated wastewater after dilution with 5 times ofirrigation water can be used for irrigation and in no case shall be discharged into surfacewater bodies.

(ii) The small and medium growers of wet coffee processing plantations of area less than 25ha, shall store the wastewater arising out of plantation activities in lined polythene sheetstorage lagoons for solar evaporation.

The sludge could be mixed with compost and used as organic manure. The small tomedium growers (10-25 ha) shall provide primary treatment comprising equalizationfollowed by neutralization for wet coffee processing wastewaters prior to its storage.

(iii)(a) The coffee processing wastes, in case of an `Instant Coffee' industry shall be treated in afull fledged two stage activated sludge plant (ASP) so as to comply with the followingstandards for irrigation:

S.No.Parameters Standards

1. PH 6.5-8.52. BOD 100m /13. TDS 2100 m /1

(b) The treated wastewater shall not be disposed into surface water bodies.

63