shats final proposal
TRANSCRIPT
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TABLE OF CONTENTS
1. INTRODUCTION ......................................................................................................................................... 1
2. PROBLEM STATEMENT ANALYSIS ............................................................................................................. 3
2.1. Justification of the project ......................................................................................................................... 4
2.2. Outline of general and specific objectives ............................................................................................... 4
2.3. Hypothesis ............................................................................................................................................. 4
3.1. Sorbate ................................................................................................................................................... 5
3.2.Chemicals for oxidation process ............................................................................................................. 5
3.3. Sorbent – preparation of surfactant-modified natural zeolite .............................................................. 5
4. METHOD ....................................................................................................................................................... 6
4.1. Batch equilibrium adsorption experiment............................................................................................. 6
4.2. Batch equilibrium oxidation experiment ............................................................................................... 6
4.3. Batch equilibrium for combined oxidation and adsorption experiment ............................................... 6
5. AREA OF STUDY ............................................................................................................................................. 7
5.1. Experimental analysis ............................................................................................................................ 7
5.2. Data analysis .............................................................................................................................................. 7
6. TIME SCHEDULE ............................................................................................................................................ 8
7. BUDGET ......................................................................................................................................................... 9
8. REFERENCES ................................................................................................................................................ 10
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1. INTRODUCTION
As rising populations and the spread of industry increasingly place stresses on the world's water
resources, the wastewater produced by many sectors - from municipalities to mining and power
generation processes - represents a vital potential source of recycled fresh water (Water –
Technologyne, 2011). This growth in population will not only increase the demand for the
shrinking supply of fresh water suitable for consumption, but it will continue to put greater
demands on the world’s agricultural system, which consumes 70% of the worlds fresh
water(Makhado R.etal, 2004). Wastewater with organic pollutants contains large quantities of
suspended solids which reduce the light available to photosynthetic organisms and setting out alter
the characteristics of the river bed, rendering it an unsuitable habit for many invertebrates
(Mohamed Nageeb Rashed, 2013).
Tea manufacturing industries contribute to this problem as its waste water (effluent) result in a
reddish colour. The effluent is generated by factors originating mainly from the washing of
equipment used at the tea manufacturing plant. The colour of wastewater from tea industries is very
high; this colour level can turn to be higher than the local and international standards (Justin K.
Maghanga et al, 2009) .This implies that the biological treatment process is not helpful in reducing
the effluent colour. The water has been adversely affected in quality. During the process of making
tea in the industries, compounds formed are coloured, so the water after washing the equipment
used becomes coloured. The coloured compounds are mainly theaflavins (TF) and the thearubigins
(TR). The main colour pigments in the tea effluent are the flavanols. Theaflavins (TF) are reddish-
orange pigment that have conjugated aromatic ring, the same chain found in the paper and kraft
mill chromophores (Justin K. Maghangaet al, 2009; MoazzamHassanpour, 2012).
Efficient techniques for the removal of highly toxic organic compounds from water have drawn
significant interest. A number of methods such as coagulation and flocculation, ion exchange,
filtration, the use of membranes, and electrodialysis have been used for the removal of organic
pollutants from polluted water and wastewater (Chen H, 1999). These methods have been found to
be limited, since they often involve high capital and operational costs. Coagulation and flocculation
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are traditional methods for the treatment of polluted water. This is a multi-stage process that
requires considerable land area and a continual supply of chemicals (Peter Holt, 2006).
A simple and efficient electrochemical method that utilizes two steel electrodes and is capable of
reducing the colour of tea effluent prior to its discharge into the river system has been used in
Kenya. There was a 100 % colour removal in all the samples, from sample point 1 (SP1) to sample
point 4 (SP4). This method could be expensive since the cost of replacement of electrodes such as
the titanium substrate insoluble anode might be high (Justin K. Maghanga et al, 2009). The
anaerobic degradability of tea beverage processing effluent was assessed using a stationary upflow
anaerobic filter. After 162 days of operation a COD removal efficiency of about 90% was achieved
by the end of the period. Removal of suspended solids was 100% in this operation. Removal of
colour was more than 85%. With this method it takes a long time to reach good removal efficiency
and there is slug formation (Isiaiah Omoso and Z.N.I Oonge). Photocatalytic oxidation for
membrane filtration processes was used to remove the color substances, which normally cause
difficulties in membrane filtration processes due to fouling using heterogeneous UV/TiO2/H2O2
reactor. It is confirmed that the technique used in this study was effective to remove only TOC at
38% and colour 400 at 89% within 150-min irrad. (Tay JH, et al, 2001). Although advanced
oxidation process can be effective for the removal of emerging compounds, these processes can
lead to the formation of oxidation intermediates that are mostly unknown at this point.
Advanced Oxidation process achieves oxidative destruction of compounds by using convectional
Ozone or H2O2(Hydrogen Peroxide). Advance oxidation process has the potential to completely
oxidize organic contaminants to CO2, H2O and mineral salts. The AIChE highlights ultraviolet
light, hydrogen peroxide and ozone as powerful oxidizing agents that destroy unwanted
contaminants and disinfect treated water without the inherent risks of using chlorine (Alfons
Vogelponl et al, 2004). This process is suitable for destroying dissolved organic contaminants,
aromatic compounds, phenols and pesticides (Tay JH et al, 2001). Major issues which have been
faced in all the oxidation technologies are the generation of intermediates (Pradeep Shuckla, 2010).
Zeolites are hydrated aluminosilicate minerals with a cage-like structure. They have been reported
as one of the emerging mineral particles (adsorbent) used in water and wastewater treatment due to
their ability to adsorb a wide range of contaminants like organics, inorganic cations and anions. It
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was concluded that the alteration of the surface properties of zeolite through chemical modification
creates new adsorption sites that have affinity for targeted ions in solution (Onyango M.S et al,
2011). Adsorption is an effective purification and separation technique used in industry especially
in water and wastewater treatments. It is the tendency of molecules from an ambient fluid phase to
adhere to the surface of a solid. Adsorption has advantages over other methods because design is
simple, can involve low investment in terms of both the initial costs and land .But it still produces a
small percentage of sludge (Teoh Tze Myang, 2010).
The objective of this research is to remove colour from wastewater using combined advanced
oxidation and adsorption technology. The effect of hydrogen peroxide and surfactant modified
zeolite on removing pollutants will be explored. With this technology of combined advanced
oxidation and adsorption process, the pollutants will be continuously oxidized as they get adsorbed
in the bed thus eliminating the need of frequently regenerating the adsorber. The effectiveness of
using combined methods in removing colour from wastewater will be investigated in this research .
The combination of advanced oxidation and adsorption process can be more effective when
compared to the individual methods.
2. PROBLEM STATEMENT ANALYSIS Contamination of our water streams seems to be increasing due to our country’s (South Africa’s)
economic growth. Increase in the population also affects the demand of water usage. Industries
produce wastewater containing toxic contaminants, where by some release colour that have
harmful effects to the environment .The colour will form a layer on top of the water which blocks
sunlight to pass through the water, this decreases photosynthesis activity and dissolution of oxygen
concentration This is affecting our ecosystem by killing the organisms which live in water. To
minimize the amount of wastewater discharged to aquatic environment, recycling of water and
removal of the industrial contaminants must be enforced. This can be achieved by implementing
and innovating advanced separation technologies.
New application of combined advanced oxidation and adsorption process can be used to reduce
water pollution by cleaning wastewater from the industrial sectors. Adsorption is one of the most
effective and reliable treatment methodologies. However, it suffers from massive mass transport
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resistance due to the size of the adsorbents. Combination of advanced oxidation and adsorption can
turn out to be more effective than using single methods.
2.1. Justification of the project Results obtained from this project will help in seeing the importance of combining existing water
purification techniques to achieve certain results depending on the problem given. As we know
that water is a necessity to both industrial and domestic sector, the recirculation of water has to be
adopted every day for us to meet the maximum demand of water. In order for us to reach that goal,
contaminants in water have to be removed with little expenditure of both time and money. New
techniques such as combined oxidation and adsorption can reduce time taken to purify a certain
amount of wastewater. Upon the success of this project, shortage of water supply will be reduced
and there will always be availability of water in industries to keep the production going. This
will not only have a positive impact on the industrial sector, it will also benefit South African
people and sustain the ecosystem.
2.2. Outline of general and specific objectives
The general objective of this project is to investigate the effectiveness of the combined advanced
oxidation and adsorption processes in purifying wastewater from the tea industry. It is
however aimed at achieving the following specific objectives.
1. To evaluate the effect of the following operational parameters: pH, initial concentration,
temperature and the sorbent mass on the removal of colour in wastewater.
2. To study the removal of colour from wastewater using advanced oxidation and adsorption
processes separately.
3. To observe the effectiveness of colour removal from wastewater using a system of
combined advanced oxidation and adsorption processes.
2.3. Hypothesis
1. The removal of colour in wastewater is affected by temperature, initial pH, intial
concentration and the mass of the adsorbent.
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2. Advanced oxidation works better alone when compared to the adsorption process.
3. The combined advanced oxidation and adsorption process is more effective in removing
impurities from wastewater than each of the individual methods.
3. MATERIALS
3.1. Sorbate
Wastewater will be supplied by Tshivhase Tea Estates Company in Vhembe District, South
Africa.
3.2. Chemicals for oxidation process
Hydrogen peroxide 30% (100 volumes) will be used for the experiments. Sodium hydroxide and
sulphuric acid will be used as pH adjusters.
3.3. Sorbent – preparation of surfactant-modified natural zeolite
The clinoptilolite that will be used for this study will be supplied by Interscan Company based in
Cape Town, South Africa. The clinoptilolite is going to be washed with deionised water to remove
dirt (dust) and certain unwashed ions and then allowed to air for a period of 24 hours.
It will then be crushed and sieved to size particles of between 150-300 µm; then the clinoptilolite
will be conditioned with 2M sodium chloride solution using a batch reactor at room temperature for
a period of 3 days at a stirrer speed of 200 rpm. The chemical conditioning of the zeolite will
improve the ion exchange performance. The conditioning removes certain cations from the
clinoptilolite that may hinder ion exchange while exposing the favoured ions of Cu2+
over Co2+
(Zamzow Murphy, 1992, Coruh, 2008). Cationic exchange of Cu on chabazite and clinoptilolite,
Zn exchange on phillipsite and chabazite has been reported (Blanchard et al., 1984: Assenov et al.,
2006). Chemical conditioning also causes exchangeable ions that are already within the zeolite.
The finally conditioned zeolite should have improved effective ion exchange capability (Bremmer
and Schultze, 1995: Gradev et al., 1988: Panayotova and Velikov, 2003). Then after 3 days the
solution will be vacuum filtered then the residue is going to be double washed with deionised water
then dried for 24 hours.
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Then the conditioned clinoptilolite will be modified using Hexadecyltrimethylammonium bromide
(HDTMABr) from Sigma-Aldrich, South Africa. A pre-weighed quantity of conditioned
clinoptilolite sample will be mixed with Hexadecyltrimethylammonium bromide solution in a
1:100 (solid: liquid) ratio. The concentration that will be used for the surfactant modified
clinoptilolite will be 3g/L. The clinoptilolite and the surface modification solution will be in
contact in a batch reactor for 3 days at stirrer speed of 200rpm. Finally the solution is going to be
vacuum filtered; the solid residue will be double washed with deionised water and air dried for 24
hours. For material characterization, UV Spectrum 258 spectrophotometer will be used to measure
the concentration of different samples.
4. METHOD
4.1. Batch equilibrium adsorption experiment
The procedure for batch equilibrium studies wastewater solutions of different pH, initial
concentration, temperature and sorbent mass will be used. Different sorbent (zeolite) mass will be
added to a solution of known concentration of the waste water contained in plastic bottles. The
bottles will be placed in a thermostatic shaker for 24 hours and the sorption media solution allowed
to reach equilibrium. Readings will be taken in duplicate for each solution to check on
repeatability.
4.2. Batch equilibrium oxidation experiment
Known concentration of hydrogen peroxide will be added to a solution of known concentration of
the wastewater contained in plastic bottles. Then the bottles will be placed in a thermostatic shaker
for 24 hours and the media solution allowed to reach equilibrium. The effect of hydrogen peroxide
dosage, pH and temperature for the removal of colour in wastewater will be investigated.
4.3. Batch equilibrium for combined oxidation and adsorption experiment
Combined advance oxidation and adsorption will be used to study the removal of colour from
waste water. Optimum sorbent mass and optimum oxidant dosage will be used on every 50ml of
waste water at different pH value. Then the bottles will be placed in a thermostatic shaker for 24
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hour period and the sorption media solution allowed to reach equilibrium. Optimum pH and
temperature will be investigated.
5. AREA OF STUDY
The wastewater samples containing theaflavins (TF) and thearubigins (TR) will be collected
from Tshivhase Tea Estates in Vhembe District of South Africa.
All laboratory test work will be done at the Tshwane University of Technology.
5.1. Experimental analysis
For batch equilibrium, samples will be analyzed using UV-Spectrophotometer to measure the
concentration of theaflavins (TF) and thearubigins (TR) in the water.
5.2. Data analysis
The results obtained from the UV-Spectrophotometer will be fitted to various equilibrium models
for various parameters which will be extracted to explore the effectiveness of adsorption using
surfactant modified clinoptilolite coupled with advance oxidation process. Different graphs will be
plotted using Excel to find the optimum adsorbent mass, hydrogen peroxide dosage, pH and
temperature values at which best colour removal percentage is obtained.
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6. TIME SCHEDULE
ID ACTIVITY DURATION/TIME
Jan Feb March April May June July August Sep Oct Nov
1 Proposal writing
2 Experimental setup
3 Literature Survey
4 Preparation of samples
5 Batch experiment for individual process
6 Batch experiment for combined process aad
7 Data Analysis and interpretation
8 Final Report
9 Final Presentation
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7. BUDGET
Materials
Amount
Materials
Wastewater Donated
Raw Zeolite R500
Chemicals
Hydrogen Peroxide R3 500
Sulphuric acid R2 000
Sodium hydroxide R1 100
Equipment’s
Plastic sample bottles (100mL) R2 500
pH meter R4 000
UV- Spectrophotometer Available (Chemistry lab)
Filter paper R1 500
Pump R5 000
Transportation
Wastewater samples R 1000
Total 21 100
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8. REFERENCES
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