Project report on Textile effluent treatment by electrochemical process

Textile effluent treatment by electrochemical process

M.L.V Government Textile & Engg College,Bhilwara (Raj.) Page 0

M.L.V. GOVERNMENT TEXTILE & ENGINEERING

COLLEGE, BHILWARA (RAJASTHAN)

CERTIFICATE

This is to certify that the project work entitled “Textile effluent treatment by electrochemical process” is carried out by :-

Arun khoiwal

Brijmohan Sharma

Dheerendra Singh

Kuldeep Shrotriya

Maya Saini

Zaved Hussain

Under my supervision and guidance during the academic year 2011-2012 and to best of my knowledge, is original work.

Mr. Jitendra Meena

(Lecturer, Textile Chemistry Department)

Project Guide



ACKNOWLEDGEMENT

We owe our indebtedness to all those who helped directly or indirectly in the accomplishment of this work.

We extend our unfeigned thanks to our Project Guide Mr. Jitendra Meena, Lecturer (Textile Chemistry), for his able guidance, valuable suggestions and active co-operation, which have made the successful and timely completion of this work possible.

We are also grateful to Mr. Amolak Goyal Sir, (Head of Taxtile Chemistry Department) and Mr. G.K.Tyagi, Principle of M.L.V. GOVERNMENT TEXTILE & ENGINEERING COLLEGE, BHILWARA (RAJASTHAN) for his kind co-operation as and when the need arose.

We would also like to thank Dr. V. K. Gupta Sir, Lecturer (Textile Chemistry), Mr. D.K. Das Sir, Lecturer (Textile Chemistry), Mr. S. S. Bairawa Sir, Lecturer (Textile Chemistry), Mr. Dinesh Rathi Sir, Technician (Textile Chemistry), for their valuable guidance & cooperation.

We are also thankful to Mr. R.S. Acharya HRD Manager (RSWM) and Mr. B.K. Singhal (RSWM) and Mr.Kogata ji HRD Manager(BPL) and Mr.C.Rajput Lab Technician (RSWM) for providing us effluent water & guiding us to do testing of effluent water required for project. We will always be obliged for his kind support.

And last but not the least; we are thankful to all our classmates of final year textile chemistry for lending hand whenever we need.

Arun Khoiwal Kuldeep Shrotriya

Brij mohan Sharma Maya Saini

Dheerendra Singh Zaved Hussain



PREFACE

Engineering is not only to grasp knowledge but also to practically apply that knowledge for the welfare of the society. We being engineers, it is our duty to give shape to our theoretical knowledge into a practical existence. Project actually does the task of molding our concepts into a physical entity. It is the test of our creativity and productivity. Apart from this, it inculcates team spirit. When the aim is completion of the project in the most effective way in the given time, various ideas and suggestion are kept together to get fruitful results. Not only the brain of one individual works but many brains work simultaneously to get some creative output in time. Co-operation is the foundation of any team, thus we learned to co-operate with each other in the worst of situation also.

This report deals with “TEXTILE EFFLUENT TREATMENT BY ELECTROCHEMICAL PROCESS”. The effect of various parameters over effluent water and other properties is studied.

It was also really very exciting to work together and we learned to face practical problems. This immense knowledge and attitude towards excellence absorbed by us will surely help us in our future endeavors.



CONTENTS

1. Certificate 2. Acknowledgement 1 3. Preface 2 4. Contents 3 5. The aim of the project 4 6. Introduction 5 7. Review of Literature

7.1. A Brief Introduction textile Wet Processing Effluent 7 7.2. Way to process of effluent treatment 8 7.3. Electrochemical Process 14 7.4. An Overview of work already done 18

8. Description of Material 22 8.1. Effluent 8.2. Equipment 8.3. Experimental Method 8.4. Testing 8.5. Research Objectives

9. Results and Discussion 25 9.1. Comparative results of ETP treated and electrochemical treated 9.2. Comparative estimation of treatment cost 57

10.Conclusion 59 11.References 60



AIM OF THE PROJECT

In context to the textile city Bhilwara, many problems seems to be highlighted related to effluent generated from process houses of Bhilwara. Many of the process houses have installed conventional ETP’s (Effluent Treatment Plant) for waste water treatment. These conventional systems arises a very big question of cost effectiveness.

Electrochemical Process could be a promising solution for overcoming this problem. This project will comprise of the study of electrochemical process for waste water generated from any of the process house of Bhilwara.

Parameters such as

pH

B.O.D (Biological Oxygen Demand)

C.O.D (Chemical Oxygen Demand) T.S.S (Total Suspended Solids)

T.D.S (Total Dissolved Solids)

etc. will be identified and will be compared of the treated waste water from the identified process houses will be done and graph will be plotted.

The main objective of this project is;

To study the extent of decolourisation by varying the treatment conditions like Time.

To compare the efficiency of Electrolytic treatment with the ETP Treated & raw effluent.

To reduce the effluent treatment cost per liter.



INTRODUCTION

Textile industries are one of the most polluting industries in terms of the volume and complexity of its effluents discharge. The dyeing and finishing operations in textile industries contribute a major share to waste water generation. Dye bath effluents, in particular, are not only aesthetic pollutants by nature of their color, but may interfere with light penetration in the receiving bodies of water, thereby disturbing biological processes. Furthermore, dye effluent may contain chemicals, which are toxic and carcinogenic. Moreover, textile waste water is known to have various pH solution (either alkaline or acidic, depending on the process used), high temp., high B.O.D, high C.O.D, and high concentration of suspended solids (SS).

Textile mill effluents are also characterized by high level of color caused by residual dyes, conventionally textile waste water is treated through biological, physical and chemical methods. Biological treatment processes are often ineffective in removing dyes which are highly structured polymers with low biodegradability.

However, various physical-chemical techniques, such as chemical coagulation, adsorption on activated carbon, reverse osmosis and ultra filtration, are also available for the treatment of aqueous streams to eliminate dyes. But those later are limited by the low concentration ranges that can be treated coupled with the high concentration in reject streams. Further, the main drawbacks of chemical coagulation are the addition of further chemicals. In recent years, Ozonation and photo oxidation have been proposed as alternatives because they were qualified to be very effective. But the high cost of these methods leads to further consideration. Indeed, electrochemical method has been successfully tested to deal with dyeing waste water. But as for some dyes, which have good water solubility and small molecule weight, traditional electrochemical ways do not work effectively.

Electro-coagulation is a process consisting of creating metallic hydroxide flocks within the waste water by electro-dissolution of soluble anodes, usually constitutes by iron or aluminum. This method has been practiced for most of



the 20th century with limited success. Recently, there has been renewed interest in the use of electro-coagulation owing to the increase in environmental restrictions on effluent waste water. Indeed, electro-coagulation has been tested successfully

The objective of the this project is to examine the feasibility of electro-coagulation in treating textile waste water, to determine the optimal operational conditions and to establish which iron hydroxide, formed during electrolysis, is responsible of electro-coagulation process.



A Brief Introduction of Textile Wet Processing Effluent

Textile wet processing is one of the major water consumer. Large quantity of water is required for wet processing of textiles and as many as 150 -300 liters of water per Kg. of fabric are used depending upon the extent of wet processing. The breakup of water required for wet processing is as follows:

Bleaching and Finishing : 60 to 65 %

Dyeing : 15 %

Printing : 10 %

Boiler : 10 to 15 %

After chemical processing of textiles, they contains many impurities as well as chemicals such as dyes, processing auxiliaries, chemicals like phosphates, sulphates, alkali, acids, heavy metals, etc. If these wastes are discharged untreated into a river, lake or even on ground, they will pose serious ecological and pollution problems [1].

The nature of textile effluent is very complex and difficult to known as various types of chemicals are used in wet processing. As far as dyes are concerned, many classes of dyes are used in textile process house, such as direct, reactive, acid, basic, vat, disperse, etc. Complexities arise due to the wide variation in structure and properties of about 3000 dyes which are used. Many waste treatments like physical, chemical, physico-chemical and biological treatments are used to solve this problem. Effluent treatment is a process in which the contaminants in wastewater are partially removed and partially changed by decomposition from highly complex organic matter to relatively stable organic matter.



WAY TO PROCESS OF EFFLUENT TREATMENT

Stages in Effluent Treatments:

1. Preliminary treatments 2. Primary treatments 3. Secondary treatments 4. Tertiary treatments

1. Preliminary Treatments:

Preliminary treatment processes for dye waste include equalization, neutralization, and possibly disinfection, although this may be done at the end of the treatment process.

1.1 Equalization: Mixing of effluents from various drains and their equalization for about 6 to 8 hours should be done to take care of wide variations and preventation of shock loads. Cement concrete tank could be used for this purpose. Equalization plays as important role in neutralizing acidic and alkaline streams. From neutralization decolouring sulphur dye effluents by hypochlorite takes place; further vat and disperse dyes are also precipitated. The temperature of the effluent is also brought down in a period of 6 hours. A periodical removal of sludge formed at the bottom helps in maintaining the efficiency of equalization. For efficient collection and removal of sludge this tank has a hopper bottom. 1.2 Neutralization: After equalization of the waste its pH correction has to be done for the efficiency of subsequent treatment. If the pH of effluent is more than 11 it should be brought to 8 by adding 10% sulphuric acid or Hydrochloric acid. The addition of acid needs to be controlled with the help of microprocessor controlled pH kit. This operation should be carried out in the flash mixer. The sulphuric acid from carbonization could be used or for this purpose flue gases



can be effectively used which is available in excess at no cost, from boiler firing installisations. During the neutralization process, bicarbonates are formed which are advantages to the environment. There is no increase in the chlorine or sulphate fraction burden.[2,3] 2. Primary Treatments: Primary treatment processes are intended to fit effluents for admission to secondary treatments. Primary treatment processes include screening, sedimentation, flotation and flocculation. These processes involve the removal of grit and solid material which may by made to settle or float out of solution. 2.1 Screening: Since the effluent contains coarse floating matters like linters and fibres in addition to heavy and readily settles able grit and dirt, the pretreatment consists of screening and grit removal. Screens of various sizes and shapes could be used depending upon the nature and size of the solids to be removed. Cleaning could be done either manually or mechanically. 2.2 Sedimentation:

The settable solids are removed by gravitational setting under quiescent conditions in sedimentation. The sludge formed at the bottom of the tank is removed as under flow either by vacuum suction or by raking it to a discharge point at the bottom of the tank for withdrawn.

2.3 Flocculation: Flocculation techniques are used, with varying degrees of success, as a tertiary treatment to remove colour from effluent. The polyelectrolyte has to be overdosed both to improve the efficiency of reaction and to enable the dark and least reactive molecules to be completely removed. This leads to residual concentrations of the polyelectrolyte in the effluent. Usually chemicals like alum, calcium chloride and ferric chloride are used as coagulating agents. [4]



3. Secondary Treatments: Primary treatments take care of only those materials that might be removed by some type of physical or mechanical action. Since most of the organic matter or material in effluent may be colloidal or dissolved, the primary treatment processes are largely ineffective in removing them. This organic material still has a high demand for oxygen which must be reduce further so that the effluent may be rendered suitable for discharge into the water bodies. Secondary treatment methods are used to reduce this organic load of textile effluents. It consists of aeration, chemical coagulation and bio-degradation.

3.1 Aeration:

This help in reducing the possibly of odour formation and handles

oxidizable organic or inorganic matter in. It also reduces the amount of sludge

produced.[5]

3.2 Chemical Coagulation:

This is very effective method of removal of color and suspended matter like

starches and gums. Alum, Ferrous Sulphate, lime and polyelectrolytes are

used depending on the type of effluent. The concentrations of these

chemicals also vary depending on quality and quantity of effluent. Coagulation

step considerably reduces BOD level. All the additions have to be made in

flash mixer provided with a suitable speed stirrer.[6]

3.3 Bio-degradation:

In this treatment, oxygen supplied to the bacteria is consumed under controlled conditions so that most of biological treatments are adequate growth of bacteria that feed on the organic material present in, oxygen and some means of achieving contact between the bacteria and the organic



matter. The micro-organisms are utilized to degrade the organic materials in the waste stream. There are two major methods of biological waste treatment: aerobic and anaerobic. They differ in their rates of reaction, the products formed from waste molecules, and the products formed with hydrogen, which is released during the oxidative processes. The most common aerobic biological treatment processes are: activated sludge, trickling filters and aerated lagoons.[7]

4. Tertiary Treatments: As the legal standards for the quality of effluent discharges are raised to values exceeding the limits of conventional treatment processes, the need for efficient tertiary (polishing) treatment processes becomes apparent. Although some processes considered to be in this category, for example, adsorption, ion-exchange and chemical oxidation, are well developed, most for, example, foam fractionation, dynamic membrane hyperflitration, gamma, radiation – induced oxidation, electrolytic treatment, etc. are still in the experimental stage. Organic Removal Processes: 1 Adsorption: Adsorption processes have got a lot of attention for colour removal from wastewater and many adsorbents can be effectively used. For adsorption, activated charcoal, chitin, Fullers earth, silica gel, bauxite, peat, wood, cellulose datives and ion exchange resins have been used to adsorb impurities from wastewater.[8] 2 Foam Separation: Foam separation is an experimental method based on the phenomena that surface active solutes collect at gas-liquid interfaces. The method has given 75% dye colour removal from industrial textile water. The foam separation technique also removes about 30 – 40% of volatile matter from the effluent. However, the chemical costs make this treatment method too expensive.



3 Chemical oxidation: This is used for decreasing the BOD of waste stream so that the residual BOD in the effluent will not deplete the total dissolved oxygen content of the stream. Ozone, H2O2, H2O2 / UV, Manganese per chlorate, etc. are generally used for this purpose. Inorganic Removal Processes: 1 Anaerobic denitrification: In anaerobic waste treatment systems, microbes of the activated sludge can, with the help of organic chemicals such as methanol, ethanol, acetic acid, etc. reduces the nitrites to gaseous nitrogen and nitrous oxide. These chemicals added, act as carbon source for the effluent.[7] 2. Algae harvesting: The effluent is deposited in shallow earthen ponds where the algae convert the nitrogen and phosphorus compounds presents into cell tissue which can be subsequently removed. 3. Electrodialysis: This is a form of ion separation which uses electrostatic fields across a membrane. The positive components are attracted to the negative membrane and the negative components to the positive membrane leaving relatively a pure solution between the membranes.

4. Ion exchange resins: These remove inorganic ions such as salts, nitrates and phosphates in which case the cations are exchanged for hydronium ions and anions for hydroxyl ions. The ion exchange resins are of different types such of cellulose ion exchangers, polystyrene based macroporous ion exchangers, etc.



5. Solvent Extraction: This is carried out by the addition of an immiscible solvent followed by high speed agitation and then separation so that organic impurities are transferred to the solvent phase.

6. Ammonia Stripping: This is intended to remove nitrogen from since at a pH 9 or more, it is possible to liberate ammonia as a gas by use of stripping towers. 7. Membrane Separation (Reverse Osmosis): This makes use of a semi permeable membrane of cellulose acetate or hollow nylon fibres and subjecting the effluents to 2.5 - 4.2 Mpa pressure which is much in excess of the osmotic pressure of the solution to remove impurities from effluents. 8. Distillation: Water is separated from wastewater through a liquid vapour conversion in which case the water is converted into the steam leaving non-volatile waste behind, when it is condensed back to liquid, it is very pure.[9]



ELECTROCHEMICAL PROCESS

What is Electrolysis?

Electrolysis is a unit process in which chemical change results from electron transfer reactions across the electrode/solution interfaces. A voltage applied between the two electrodes in an electrolytic cell drives these reactions. [10]

For different applications of electrochemical technology the same fundamental principle of electrolysis is used; while its practical manifestations may be quite different with, for example, cell configurations, electrode materials and their sizes & dimensions, electrolytes and separators which are each designed to meet the particular demands of the application. In effluent treatment, the objective may be the removal of color, salts, heavy metals, toxic organics or inorganic or a reduction of COD.

Application of Electrolytic Technique in effluent treatment

An alternative to the previously mentioned color elimination techniques is the principle of electrochemical destruction which forms the basis of our project. The main advantage of this technique is that the only requirement is a source of electric power. The addition of electrolytes as mentioned in most of the studies & papers is not necessary since the Effluent from Reactive dyeing Industry contains sufficient salts.

Electrochemical methods offer, in fact, unique reaction conditions, as the working electrode has at the same time the features of an easily recyclable heterogeneous catalyst and the capacity of feeding quantitatively and selectively the simplest and most economic reagent, the electron, then allowing extremely mild operative conditions.[6]

Electrochemical processes are probably the most adequate tool in the aqueous effluent treatment. It does not require chemical additions and indeed electrons are the only reactants added to the process to simulate



reaction. These processes include electro-oxidation & electro-coagulation.[6,8]

Electro-oxidation is an attractive alternative for treating aqueous stream containing the organic compounds via simultaneous evolution of oxygen at an anode surface which is probably most adequate tool in the aqueous effluent treatment, ideally suited to present age where environmental consideration are always to the fore. The electro-oxidation is mediated reaction and occurs via oxygen atom’s transfer from water in the solvent phase to oxidation product.[11]

The generic reaction of anodic oxygen transfer may be given as:

R + XH2O ROX + 2XH+ + 2Xe-

Where, R - Organic compound reactant

ROX - Oxidation product

Electro-coagulation is a phenomenon in which the charged particle are neutralized by neutral collision with counter ions present in the coagulant added, and are agglomerated, followed by the process of sedimentation. In the Electro-coagulation process the coagulant is generated in-situ by the electrolytic oxidation of a sacrificial anode material. Charged ionic species are removed from the effluent by allowing it to react: (i) With an ion having opposite charge, or (ii) With flocks of metallic hydroxides generated within the effluent.

After completion of electrolysis (which is noted with considerable drop in current) the treated effluent is collected in retention tank from which it is transferred at constant flow rate to the filtration unit/process. At this stage the sludge is removed and filtered water is allowed to flow for next process. Looking to the end use, the treated water can be used directly in dyeing, or can be used for agriculture purpose.



Electro coagulation involves dissolution of metal from the anode with simultaneous formation of hydroxyl ions and hydrogen gas occurring at the cathode.

Possible interactions in Electrolytic Effluent Treatment

Fig.:- Interactions within the electrochemical process

The pH, pollutant type and concentration, the bubble size, position & distance between electrodes, flock stability and agglomerate size all influences the operation of the electrolytic cell. The complexity and number of possible interactions are highlighted in Figure above. The overall mechanism is a combination of mechanisms functioning synergistically. The dominant mechanism may vary throughout the dynamic process as the reaction progresses. The dominant mechanism will almost certainly shift with changes in operating parameters and pollutant types.

A current is passed through the electrodes, oxidizing the metal (M) to its cation (Mn+) (Equation 1). Simultaneously, water is reduced to hydrogen gas and the hydroxyl ion (OH‾) (Equation 2).



The cation hydrolyzes in water forming a hydroxide with the dominant species determined by solution pH. Equations 3 – 6 illustrate this in the case of aluminium cathode.

Highly charged cations destabilize any colloidal particles by the formation of polyvalent polyhydroxide complexes. These complexes have high adsorption properties, forming aggregates with pollutants. Evolution of hydrogen gas aids in mixing and hence flocculation. Once the flock is generated, the electrolytic gas in the form of bubble creates a flotation effect, removing the pollutants to the flock - foam layer at the liquid surface.

There are varieties of ways in which species can interact in solution:

1. Migration to an oppositely charged electrode (Electrophoresis) and aggregation to due to charge neutralization.

2. The cation or hydroxyl ion (OH-) forms a precipitate with the pollutant.

3. The metallic cation interacts with OH- to form hydroxide, which has high adsorption properties thus bonding to the pollutant (bridge coagulation).

4. The hydroxides form larger lattice-like structures and sweeps through the water (sweep coagulation).

5. Oxidation of pollutants to less toxic species.



An Overview Of work already Done

Current, the textile dyeing wastewater is one of the most important sources of pollution. The type of this wastewater has the characteristics of higher value of color, BOD and COD, Complex composition, large emission, widely distributed and difficult degradation. If being directly discharged without being treated, it will bring serious harm to the ecological environment. Because of the dangers of dyeing wastewater, many countries have enacted strict emissions standards, but there is no uniform standard currently.

1. Zongping Wang, Miaomiao Xue, Kai Huang and Zizheng Liu Huazhong University of Science and Technology China carried out a study on Textile Dyeing Wastewater Treatment - It appears that an ideal treatment process for satisfactory recycling and reuse of textile effluent water should involve the following steps. Initially, refractory organic compounds and dyes may be electrochemically oxidized to biodegradable constituents before the wastewater is subjected to biological treatment under aerobic conditions. Color and odor removal may be accomplished by a second electro oxidation process. Microbial life, if any, may be destroyed by a photochemical treatment. The treated water at this stage may be used for rinsing and washing purposes; however, an ion-exchange step may be introduced if the water is desired to be used for industrial processing.

2. Ju¨ ttner a,*, U. Galla b, H. Schmieder b carried out a study on Electrochemical approaches to environmental problems in the process industry-A number of selected electrochemical processes and devices, which have been developed in the process industry in recent years for environmental protection, has been presented and was briefly discussed. Some, but not all, of them have been tested successfully in the laboratory or even at a pilot scale, and some have already reached commercialization. Due to the specific advantages in a number of applications, electrochemical processes for the treatment of waste and prevention of pollution will find increasing acceptance in future



developments. In particular, there are many examples where industrial processes involve chemical oxidation: reduction steps, which could easily be replaced by a direct electrolysis step thus avoiding costly space, time and energy consuming separation processes leading to a cleaner and process integrated environmental technology.

3. Eduardo Arevalo, Wolfgang Calmano carried out a study on Studies on electrochemical treatment of wastewater contaminated with organotin compounds - The experimental work of this study showed that electrochemical treatment is a technology suitable for eliminating organotins in dockyard waters down to very low concentration targets in the range of 100 ng L−1. Reaching such low concentrations has proved difficult with “off the shelf” technologies such as activated carbon. The inorganic tin formed as final product of degradation can be considered harmless at such concentrations, and disposed into the environment. The results indicated that the performance of the electrolysis employing Ti/IrO2 and BDD anodes was in a similar range, contrarily to the initial hypothesis that the high yield of hydroxyl radicals at BDD anodes would result in a much faster degradation rate using BDD. Reasons are due to the presence of active chlorine compounds starting from electrochemical chloride oxidation, and other oxidants, which also lead to the degradation of organotins. Such behavior was confirmed by other experiments conducted to decompose the blue dye Indigo Carmine. These experiments showed when chloride concentration in the water decreased, BDD clearly outperformed Ti/IrO2.

4. A. Wilcock', M. Brewster2, W. Tinche carried out a study on USE OF ELECTROCHEMICAL TECHNOLOGY TO TREAT TEXTILE WASTEWATER - This gives a report of three independent studies which illustrate the effectiveness of electrochemical treatment of effluent containing three different classes of dye. The three studies clearly indicate marked color removal from the effluent. Furthermore, two of the studies demonstrate that it is possible to reuse the treated dyebath, a strategy that would significantly minimize the quantity of effluent discliar_red



into the environment without compromising dyeing quality. The benefits of the electrochemical system are numerous and include versatility, ease of operation and economy.

5. Muhammad Saleem1, Alaadin A. Bukhari2 and Muhammad Noman Akram1 have reported on ELECTROCOAGULATION FOR THE TREATMENT OF

WASTEWATER FOR REUSE IN IRRIGATION AND PLANTATION - Raw wastewater generated at KNPC was characterized for possible reuse in landscape irrigation and plantation. Analysis of the wastewater shows that it is of weak to medium strength compared to the typical domestic wastewater (MetCalf & Eddy, 2003). However, raw wastewater is not suitable for direct. Since their various parameters (solids, turbidity, BOD, COD, metals and total Coliform) were above international standards. A laboratory scale EC process was utilized to treat the raw wastewater in order to bring the quality up to the required level. Effect of various parameters such as operating time, current density and inter-electrode spacing was evaluated. It was found that 91.8%, 77.2% and 68.5% removal in turbidity, COD and TSS were achieved within 30 minutes of EC treatment. Further increase in treatment time did not improve their removal efficiency. Change in pH value during EC treatment was also noted and maximum value of 8.4 was observed at the end of treatment which is within allowable limits. Applied current density has significant effect on the removal efficiency of EC process. It was found that the current density of 24.7 mA/cm2 has the highest removal efficiency for studied. Further increase in current density showed insignificant improvement in removal efficiency. The effect of inter electrode spacing on the removal of TSS and turbidity reveals that their removal efficiency.

6. Khanittha Charoenlarp* and Wichan Choyphan have reported on REUSE

OF DYE WASTEWATER BY COLOR REMOVAL WITH ELECTROCHEMICAL PROCESS - Electro coagulation is one of the most effective techniques to remove color and organic pollutants from wastewater. The decolonization of dye solution by electrochemical was affected by electrode materials, electrical potentials, and electrolysis time of



electrolysis. The results showed that the electrical potentials was the most effective parameters. The proper conditions to reactive wastewater treatment by coagulation process were 20 volts aluminum electrode at 180 electrolysis time. The effectiveness in color removal and dissolved solid were 96.05% and 35.18%. The proper conditions to basic wastewater treatment by coagulation process were 25 volts iron electrode at 180 electrolysis time. The effectiveness in color removal, dissolved solid, suspended solid, turbidity, and COD were 85.61%, 30.67%, 66.67%, 20.61%, and 79.51% respectively.

Suggestions 1. Study life time of electrode and space between electrodes 2. Comparison of the effectiveness and the cost in water treatment by coagulation with chemicals, and with electrical current.



Description of Materials

Effluent:

We have taken effluent water as well as ETP’s treated water from the BPL Industry and RSWM Bhilwara (Rajasthan) for doing our project work.

EQUIPMENTS:

1. Electrodes – aluminum and stainless steel 2. pH meter 3. Filter paper 4. Glass beaker (1000 ml cap.), 5. Digital Power supply kit, 6. wires, 7. Funnel, 8. Conical flask 9. Weighing Balance 10.Hot plate

EXPERIMENTAL SET UP

The electrodes are placed inside the beaker (acting as an undivided electrolytic cell), at opposite circumferential ends. The distance between the electrodes is around 40-50 mm. The electrodes are 150 mm in length and the shape of aluminum (cathodes) is round having 6 mm diameter and, while the stainless steel (anode) is like round in shape. These are the cheapest source of electrodes (scrap material), which gives outstanding results, hence no question of going for Lead, Titanium, Graphite or Platinum electrodes.



Floating sludge was removed from the top and settling sludge was allowed to settle completely before filtration. Constant 7.5 volt Direct Current (DC) source was provided with the help of a rectifier having an input of 230 V by digital power supply kit.

The extent of decolourisation is mainly controlled by 6 important process parameters;

Potential Difference (Voltage) Current Density (Ampere) Effluent pH Treatment Time (Minutes) Surface area of electrode Flow rate

The electrolytic treatment of the composite effluent is carried out at standard conditions, and separately a chemical coagulation treatment with lime-ferrous sulphate & polyelectrolyte is carried out with the similar effluent. The results of both the treatments, mainly absorbance values, COD, BOD & TDS are than compared.



TESTING:

1. Effluent testing: a. COD b. T.S c. TDS d. T.S.S e. BOD f. pH

By studying the electrochemical on color and COD removal at different parameters we will propose the optimum conditions under which three factors work synergistically to give maximum removal of color and COD.

Research Objectives

The decolorization method being investigated in this thesis makes use of Electrolytic Technique to remove dyes from the effluent water. The application of electrochemical processes on an industrial scale will depend on the cost of the cell. And the electric power required. But other important factors also have to be considered, such as the biological quality & reusability of the treated water.

The main objective of this project is;

To study the extent of decolourisation by varying the treatment conditions like Time.

To compare the efficiency of Electrolytic treatment with ETP Treated & Raw effluent.

To reduce the effluent treatment cost per liter.



RESULTS AND DISCUSSIONS

We processed as per the experimentation method and then carried out testing.

The results that we obtained are as follows:-

SAMPLE - 1

Table no. 1:- Consisting of experimental data’s for 1st sample of effluent water taken from RSWM industry bhilwara and treatment time is 10 minutes.

Parameters P. C. B.

standard Untreated

effluent ETP

Treated Electrochemical

treated R.O.

pH 5.5-9.0 10.5 11.5 9.5 6.7

T.S.(ppm) - 9080.40 5537.60 7500.40 _

T.D.S.(ppm) 2000 8800.00 5500.00 7460.00 680

T.S.S.(ppm) 100 280.40 37.60 40.40 nil

COD (ppm) <250 371.14 252.57 284.57 12

BOD(ppm) <30 230.00 38.00 105.00 _

Temp.(°c) <40 42 40 40 39

Note - We have studied from this table that we don’t get better result in compare to ETP treated results in 10 minutes of electrochemical treatment. But as we increase the time of treatment by electrochemical process about 30 min we’ll get good results compare to ETP treated.



As we increase the treatment time we get T.S in decreasing order compare to

ETP treated results.

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of T.S of 1st Sample

Raw Effluent

ETP Treated

Electrochemical

Treated

0

50

100

150

200

250

300

350

400

10 20 30 40

C.O

.D (

PP

M)

TIME (IN MIN)

Comparision of C.O.D of 1st Sample

Raw Effluent

ETP Treated

Electrochemical

treated



0

50

100

150

200

250

10 20 30 40

C.O

.D (

PP

M)

TIME (IN MIN)

Comparision of B.O.D of 1st Sample

Raw Effluent

ETP Treated

Electrochemical

treated




Note - We have studied from this table that we get 30.06% less T.S, 26.68% less C.O.D, and 58.26% less B.O.D compare to raw effluent within the 20 min treatment of electrochemical process.

Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.5 11.5 9.5 6.7

T.S.(ppm) - 9080.40 5537.60 6350.00 _

T.D.S.(ppm) 2000 8800.00 5500.00 6811.40 680

T.S.S.(ppm) 100 280.40 37.60 38.60 nil

COD (ppm) <250 371.14 252.57 272.54 12

BOD(ppm) <30 230.00 38.00 96.00 _

Temp.(°c) <40 42 40 39 39




Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.5 11.5 9.0 6.7

T.S.(ppm) - 9080.40 5537.60 5453.70 _

T.D.S.(ppm) 2000 8800.00 5500.00 5417.40 680

T.S.S.(ppm) 100 280.40 37.60 36.30 nil

COD (ppm) <250 371.14 252.57 250.10 12

BOD(ppm) <30 230.00 38.00 89.00 _

Temp.(°c) <40 42 40 39 39





Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.5 11.5 9.0 6.7

T.S.(ppm) - 9080.40 5537.60 5449.80 _

T.D.S.(ppm) 2000 8800.00 5500.00 5413.80 680

T.S.S.(ppm) 100 280.40 37.60 36.00 nil

COD (ppm) <250 371.14 252.57 249.20 12

BOD(ppm) <30 230.00 38.00 88.00 _

Temp.(°c) <40 42 40 39 39




1. Graph between T.S v/s Time

2. Graph between T.D.S v/s Time

0

1000

2000

3000

4000

5000

6000

7000

8000

10 20 30 40

T.S

(PP

M)

TIME (IN MIN)

T.S (PPM)

T.S (PPM)

0

1000

2000

3000

4000

5000

6000

7000

8000

10 20 30 20

T.D

.S (

PP

M)

TIME (IN MIN)

T.D.S (PPM)

T.D.S (PPM)



3. Graph between T.S.S v/s Time

4. Graph between C.O.D v/s Time

33

34

35

36

37

38

39

40

41

10 20 30 20

T.S.

S (P

PM

)

TIME (IN MIN)

T.S.S (PPM)

T.S.S (PPM)

230

240

250

260

270

280

290

10 20 30 40

C.O

.D (

PP

M)

TIME (IN MIN)

C.O.D (PPM)

C.O.D (PPM)



SAMPLE – 2

Table no. 5:- Consisting of experimental data’s for 2nd sample of effluent water taken from RSWM industry bhilwara and treatment time is 10 minutes.

Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.9 11.6 10.0 6.7

T.S.(ppm) - 8960.00 5247.30 6970.00 _

T.D.S.(ppm) 2000 8641.80 5200.50 6915.80 680

T.S.S.(ppm) 100 318.20 66.80 84.20 nil

COD (ppm) <250 386.70 248.47 313.00 12

BOD(ppm) <30 246.00 56.00 92.00 _

Temp.(°c) <40 42 41 40 39




0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of T.S of 2nd Sample

Raw Effluent

ETP Treated

Electrochemical

Treated

0

50

100

150

200

250

300

350

400

450

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of C.O.D of 2nd Sample

Raw Effluent

ETP Treated

Electrochemical

Treated



0

50

100

150

200

250

300

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of B.O.D of 2nd Sample

Raw Effluent

ETP Treated

Electrochemical

Treated




Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.9 11.6 9.8 6.7

T.S.(ppm) - 8960.00 5247.30 5700.00 _

T.D.S.(ppm) 2000 8641.80 5200.50 5628.40 680

T.S.S.(ppm) 100 318.20 66.80 71.60 nil

COD (ppm) <250 386.70 248.47 276.90 12

BOD(ppm) <30 246.00 56.00 89.00 _

Temp.(°c) <40 42 41 39 39





Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.9 11.6 9.5 6.7

T.S.(ppm) - 8960.00 5247.30 5200.00 _

T.D.S.(ppm) 2000 8641.80 5200.50 5134.20 680

T.S.S.(ppm) 100 318.20 66.80 65.80 nil

COD (ppm) <250 386.70 248.47 247.30 12

BOD(ppm) <30 246.00 56.00 84.10 _

Temp.(°c) <40 42 41 39 39





Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.9 11.6 9.5 6.7

T.S.(ppm) - 8960.00 5247.30 5192.00 _

T.D.S.(ppm) 2000 8641.80 5200.50 5127.00 680

T.S.S.(ppm) 100 318.20 66.80 65.00 nil

COD (ppm) <250 386.70 248.47 246.80 12

BOD(ppm) <30 246.00 56.00 80.30 _

Temp.(°c) <40 42 41 39 39






0

1000

2000

3000

4000

5000

6000

7000

8000

10 20 30 40

T.D

.S (

PP

M)

TIME (IN MIN)

T.D.S (PPM)

T.D.S (PPM)

0

10

20

30

40

50

60

70

80

90

10 20 30 40

T.S.

S (P

PM

)

TIME (IN MIN)

T.S.S (PPM)

T.S.S (PPM)




0

50

100

150

200

250

300

350

10 20 30 40

C.O

.D (

PP

M)

TIME (IN MIN)

C.O.D (PPM)

C.O.D (PPM)



SAMPLE - 3

Table no. 9:- Consisting of experimental data’s for 3rd sample of

effluent water taken from BPL industry bhilwara and treatment

time is 10 minutes.

Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 11.0 11.5 10.8 6.7

T.S.(ppm) - 6000.00 3500.00 4110.00 _

T.D.S.(ppm) 2000 5900.00 3454.70 4061.20 680

T.S.S.(ppm) 100 100.00 45.30 48.80 nil

COD (ppm) <250 284.30 218.50 258.10 12

BOD(ppm) <30 208.6 52.00 104.80 _

Temp.(°c) <40 40 40 39 39

Note - We have studied from this table that we get 31.5% less T.S, 9.15% less C.O.D, and 50% less B.O.D compare to raw effluent within the 10 min treatment of electrochemical process.



0

1000

2000

3000

4000

5000

6000

7000

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of T.S of 3rd Sample

Raw Effluent

ETP Treated

Electrochemical

Treated

0

50

100

150

200

250

300

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of C.O.D of 3rd Sample

Raw Effluent

ETP Treated

Electrochemical

Treated



0

50

100

150

200

250

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of B.O.D of 3rdSample

Raw Effluent

ETP Treated

Electrochemical

Treated



Table no. 10:- Consisting of experimental data’s for 3rd sample of effluent water taken from BPL industry bhilwara and treatment time is 20 minutes.

Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 11.0 11.5 10.0 6.7

T.S.(ppm) - 6000.00 3500.00 3446.20 _

T.D.S.(ppm) 2000 5900.00 3454.70 3403.50 680

T.S.S.(ppm) 100 100.00 45.30 42.70 nil

COD (ppm) <250 284.30 218.50 239.90 12

BOD(ppm) <30 208.6 52.00 96.60 _

Temp.(°c) <40 40 40 39 39





Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 11.0 11.5 9.6 6.7

T.S.(ppm) - 6000.00 3500.00 3376.00 _

T.D.S.(ppm) 2000 5900.00 3454.70 3335.90 680

T.S.S.(ppm) 100 100.00 45.30 40.10 nil

COD (ppm) <250 284.30 218.50 223.80 12

BOD(ppm) <30 208.6 52.00 84.20 _

Temp.(°c) <40 40 40 39 39





Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 11.0 11.5 9.5 6.7

T.S.(ppm) - 6000.00 3500.00 3372.00 _

T.D.S.(ppm) 2000 5900.00 3454.70 3332.30 680

T.S.S.(ppm) 100 100.00 45.30 39.7 nil

COD (ppm) <250 284.30 218.50 218.20 12

BOD(ppm) <30 208.6 52.00 80.00 _

Temp.(°c) <40 40 40 39 39






0

500

1000

1500

2000

2500

3000

3500

4000

4500

10 20 30 40

T.D

.S (

PP

M)

TIME (IN MIN)

T.D.S (PPM)

T.D.S (PPM)

0

10

20

30

40

50

60

10 20 30 40

T.S.

S (P

PM

)

TIME (IN MIN)

T.S.S (PPM)

T.S.S (PPM)




190

200

210

220

230

240

250

260

270

10 20 30 40

C.O

.D (

PP

M)

TIME (IN MIN)

C.O.D (PPM)

C.O.D (PPM)



SAMPLE - 4

Table no. 13:- Consisting of experimental data’s for 4th sample of effluent water taken from BPL industry bhilwara and treatment time is 10 minutes.

Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.5 11.2 10.0 6.7

T.S.(ppm) - 6800.00 3515.00 4100.50 _

T.D.S.(ppm) 2000 6572.00 3429.70 3990.50 680

T.S.S.(ppm) 100 227.70 86.00 110.00 nil

COD (ppm) <250 392.50 283.30 333.70 12

BOD(ppm) <30 228 76 156 _

Temp.(°c) <40 41 40 40 39




0

1000

2000

3000

4000

5000

6000

7000

8000

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of T.S of 4th Sample

Raw Effluent

ETP Treated

Electrochemical

Treated

0

50

100

150

200

250

300

350

400

450

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of C.O.D of 4th Sample

Raw Effluent

ETP Treated

Electrochemical

Treated



0

50

100

150

200

250

0 10 20 30 40 50

T.S

(pp

m)

TIME (IN MIN)

Comparision of B.O.D of 4th Sample

Raw Effluent

ETP Treated

Electrochemical

Treated




Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.5 11.2 9.7 6.7

T.S.(ppm) - 6800.00 3515.00 3715.00 _

T.D.S.(ppm) 2000 6572.00 3429.70 3620.00 680

T.S.S.(ppm) 100 227.70 86.00 95.00 nil

COD (ppm) <250 392.50 283.30 307.80 12

BOD(ppm) <30 228 76 119.40 _

Temp.(°c) <40 41 40 39 39





Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.5 11.2 9.4 6.7

T.S.(ppm) - 6800.00 3515.00 3513.00 _

T.D.S.(ppm) 2000 6572.00 3429.70 3427.80 680

T.S.S.(ppm) 100 227.70 86.00 85.20 nil

COD (ppm) <250 392.50 283.30 280.80 12

BOD(ppm) <30 228 76 103.8 _

Temp.(°c) <40 41 40 39 39

Note - We have studied from this table that we get 48.33% less T.S, 28.57% less C.O.D, and 54.82% less B.O.D compare to raw effluent within the 30 min treatment of electrochemical process




Parameters P. C. B.

standard Untreated

effluent ETP


treated R.O.

pH 5.5-9.0 10.5 11.2 9.4 6.7

T.S.(ppm) - 6800.00 3515.00 3510.00 _

T.D.S.(ppm) 2000 6572.00 3429.70 3425.90 680

T.S.S.(ppm) 100 227.70 86.00 84.10 nil

COD (ppm) <250 392.50 283.30 280.00 12

BOD(ppm) <30 228 76 100.30 _

Temp.(°c) <40 41 40 39 39






31003200330034003500360037003800390040004100

10 20 30 40

T.D

.S (

PP

M)

TIME (IN MIN)

T.D.S (PPM)

T.D.S (PPM)

0

20

40

60

80

100

120

10 20 30 40

T.S.

S (P

PM

)

TIME (IN MIN)

T.S.S (PPM)

T.S.S (PPM)




250

260

270

280

290

300

310

320

330

340

10 20 30 40

C.O

.D (

PP

M)

TIME (IN MIN)

C.O.D (PPM)

C.O.D (PPM)



Comparative Estimation of Treatment Cost

For the treatment we have taken 1000 ml solution of effluent each time. The total cost is calculated is for per 1000 litre of effluent. We have optimized the process and in it we have used the following parameters of Voltage, Current and time.

1. Voltage :- 7.5 volt 2. Current: - 0.7 ampere. 3. Time: - 30 min.

Depending on above parameters the electricity cost has been calculated as follows.

Power = Voltage X Current.

(Watt) (Volt) (Ampere)

P = 7.5 X 0.7 = 5.25 Watt

Electricity consumed per Hour:-

Energy = V X I X Time

= 5.25 X 0.5 ………. (30 min = 0.5 hrs)

= 2.625 Watt hour

Cost of 1 unit of electricity for industrial use is around Rs.5/unit.

i.e. For 1 Kilowatt hour(1000 Watt Hour) = Rs. 5

Hence total cost of energy consumed for 1000 litre of effluent will be,

Energy cost = 2.625 X 5 X 1000 = 13.125 Rs / 1000 Liter

1000



Costing of the Conventional Process:-

Chemical cost:-Rs 14.5 / 1000 Liter

Men Power Cost:-Rs 0.75 / 1000 Liter

Power Cost:-Rs 1.75 / 1000 Liter

Process Cost:-

Total Treatment Cost = Rs 17/ 1000 Liter.

Though Electrolytic treatment is costly due to cost of electricity, but the overall treatment cost & reusability of the treated water makes it the best available option. However, the electricity cost can be reduced or completely eliminated by a onetime investment on a non-conventional energy sources- preferably solar energy.

17

13.125

Conventional Electrochemical treated

Comparative Estimation of Treatment Cost per 1000 liter

Conventional Electrochemical treated



CONCLUSION

The data obtained in this project work reveal that high level of decolourisation is achieved with considerable lowering of toxicity & with ecofriendly nature. The selected effluent’s intense color can be removed to the extent of 95-99% decolourisation, 27.11% BOD removal and 32.7% COD removal in a lab scale system with compare to Raw effluent. Further the effluent did not require any additive like reducing agents or catalytic agents to reduce the dye & organics present in the effluent.

The present research clearly demonstrated that textile wastewater can be effectively treated by electrochemical method. An undivided cell containing an Aluminum cathode & Stainless steel anode were used for this purpose. Complete colour removal for a effluent is achieved within 30 minutes at 7.5 volt, 0.7 amps & 9.5 pH (actual effluent pH), which are pre-standardized parameters.



References

1. Wasif A.I., Desai J.R. and Kane C.D., Book of Papers, 55th All India Textile Conference, pg.262

2. Anon, Textile Horizons, 7(12), 58 (1987). 3. Leary R.H., Textile Asia, 11(10), 118 (1980). 4. Patel M.G. and Joshi H.D., Mantra Bulletin, 16(12), 13 (1998). 5. Rhoume G.A., American Dyestuff Reporter, 17(9), 6 (1971). 6. Leary R.H., Textile Asia, 11(11), 116(1980). 7. Mathew R. P, American Dyestuff Reporter, 63(8), 19 (1974). 8. Thampi J. Colourage, 44(11), 37(1997). 9. Porter J. J., American Dyestuff Reporter, 60(8), 17(1971). 10.Anon., http://www.indiantextilejournal.com/Content 11.W. B. Achwal, Colourage, 43(9), 55(1996). 12. Dr. A. A. Ansari & Dr. B. D. Thakur(2002), Colourage, Vol.-xlvi No.9,Feb

27-30

13.Usha Sayed UMICT,Mumbai,Asian Textile Journal (jan.2004),Vol.13,No.1,86-91

14.A.R. Rathore, G.S. Kakad and B. Suman (March-April 2006),vol.:66,No.6,289-292,300.

http://www.indiantextilejournal.com/Content

Documents

Project report on Textile effluent treatment by electrochemical process