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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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