TREATING WASTE WATER USING ELECTROCOAGULATION APPROACH

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1 International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 11, November 2018, pp , Article ID: IJCIET_09_11_004 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed TREATING WASTE WATER USING ELECTROCOAGULATION APPROACH S. Packialakshmi, P.M Bhawani Department of Civil Engineering, Sathyabama Institute of Science and Technology, Chennai, Tamilnadu, India ABSTRACT Performance of Electro coagulation method is evaluated by treating various sources of water. The electrodes of stainless steel are used for arranging electrolytic cell. The treatment efficiency is assessed by varying electrical potential and concentration time. The parameters namely ph, Total Dissolved Solids (TDS), Total Hardness, Electrical Conductivity, Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) were tested and results were compared to assess the performance of treatment process. Effects of operating parameters such as varying electrical potential (3V-12V) and concentration time (10 minutes- 30 minutes) were evaluated for optimum operating conditions. The result shown that identified electrolytic arrangement is significantly efficient for treating BOD and COD when compared to other water quality parameters especially for grey and industrial water samples. The highest removal efficiency under optimum operating condition for COD and BOD removal were obtained with 58% and 67% in grey water sample whereas in industrial waste water sample, the efficiencies are 53% and 57%. Further, the study suggested the various simulations in the operating parameters with the economic considerations to optimize the findings and for upcoming progress in the application of this advanced technology. Keywords: Electrochemical Waste water treatment; Stainless Steel electrodes; Electro coagualtion; Electrical potential Cite this Article: S. Packialakshmi, P.M. Bhawani, Treating Waste Water Using Electrocoagulation Approach. International Journal of Civil Engineering and Technology, 9(11), 2018, pp INTRODUCTION The rapid growth of population and its growing needs has meant that per capita availability of fresh water has declined sharply from 3000 cubic meters to 1123 cubic meters over the past 50 years. The deterioration of the environmental situation in India and the high water scarcity level need for an immediate action for the treatment of domestic and industrial waste water and the upgrading of existing over loaded treatment plants. Wastewater reuse will also play 47

2 Treating Waste Water Using Electrocoagulation Approach an important role in the re-allocation of scarce water resources among sectors of the economy. Many, especially in marginalized rural areas, leave the wastewater to simply seep into the streets inducing bad odors, spreading insects and possibly causing diseases. If the wastewater released directly into rivers, lakes and other water bodies, it can be a source of pollution which can affect marine life, human health, ecology etc. Groundwater is the precious and vulnerable resources. Dependence on this resource will continue to grow, particularly in areas where surface water is limited or has already been fully allocated for existing uses, including in stream requirements (and particularly ecosystem needs).thus, it becomes imperative to think about water purification using effective and inexpensive techniques and its reusability. Various techniques are employed nowadays to treat the waste water such as Advance Oxidation Process (AOPs), Down flow System, Dynamic Membrane Bioreactor, Electrochemical process, Biological methods and Conventional filtration system. 2. ELECTROCOAGULATION METHOD Electrocoagulation has become a major treatment method especially for industrial waste water which contains different effluents released from industries like textile, chemical, leather, metal, food processing etc. Electrocoagulation (EC) is a broad-spectrum of treatment technology that removes total suspended solids (TSS), heavy metals, emulsified oils, bacteria and other contaminants from water[1,2,3]. Electrocoagulation (EC), the passing of electric current through water, has proven very effective in the removal of contaminants from water. Electrocoagulation systems have been in existence for many years using a variety of anode and cathode geometries, including plates, balls, fluidized bed spheres, wire mesh, rods and tubes. EC uses a proprietary treatment chamber and electricity to treat a wide range of differing waste streams containing heavy metals, virus, bacteria, pesticides, arsenic, cyanide, Biochemical oxygen demand (BOD), Total dissolved solids (TDS), and Total suspended solids (TSS). It is used to treat municipal, industrial and commercial wastewater. The ease of the process and its high ability to remove the pollutants from water has made it a useful method [4,5,6]. The various parameters of electrocoagulation which affects the treatment process are electrodes types, shape and size, ph at which electrocoagulation is taking place and current density. These parameters have large influence on the effectiveness of the electrocoagulation. The present study aims to identify the feasible treatment technique to treat the various sources of water which requires preliminary treatment before discharging in to the natural streams or prior to deploy the cost intensive treatment process. The study aimed to analyze the treatment process for different sources of water like i) Groundwater which requires treatment to use it for drinking purposes ii) Grey water which includes water from showers, bathtubs, sinks, kitchen, dishwashers, laundry tubs, and washing machines iii) Industrial waste water contains chemical constituents which requires preliminary treatment at least before letting out to main water streams. This will help in identifying the efficiency of selected treatment process Treatment of paint manufacturing wastewater (PMW) is performed by using the process of electrocoagulation [7]. Effects of operating parameters for the EC process such as electrode type was Al or Fe. The result showed that initial ph (2 10), current density (5 80 A/m 2 ) and operating time (0 50 min) were evaluated for optimum operating conditions. The highest removal efficiencies for COD and TOC in PMW were obtained with 93% and 88% for Fe and 94% and 89% for Al electrodes at the optimum conditions (35 A/m 2, 15min and ph 6.95). Removal of copper, chromium and nickel from metal plating wastewater is 48 editor@iaeme.com

3 S. Packialakshmi, P.M. Bhawani approached using electrocoagulation method [8]. It was investigated with iron and aluminum electrodes with monopolar configurations. Increase in current density leads to increase in flocculates of Al, Feand OH and thus increases the treatment efficiency. The study on optimization of electrocoagulation process to treat grey water in batch mode using response surface methodology indicated that electrocoagulation process can be in large scale level to treat the grey waste water with high removal efficiency of TS, COD and FC [9]. The study on removal and recovery of humic like substances from industrial secondary effluent utilized the process of membrane electrolysis and electro-coagulation [10,11]. The results show that electrochemical methods are an interesting option for humic like substances removal/recovery and could compete with conventional oxidation and coagulation methods 3. THEORY OF ELECTROCOAGULATION The passage of current by means of electrode generates in situ coagulants by electrically dissolving ion electrodes. Stainless steel electrode predominantly releases Fe +2 ions. The metal ions generation takes place at the anode, while hydrogen gas is released from the cathode. The chemical reactions taking place at the electrodes are given as follows: For stainless steel anode Fe 2 e Fe +2 At alkali conditions Fe OH Fe (OH) 2 At acidic conditions 4 Fe 2+ + O H 2 O 4 Fe OH In addition of oxygen evaluation 2 H 2 O 4 e O H + For stainless steel cathode 2 H 2 O + 2 e H OH Freshly formed amorphous Fe(OH) 2 has large surface areas that are beneficial for rapid adsorption of soluble organic compounds and trapping of colloidal particles.the present study is conducted with the pre-testing and post-testing of parameters namely TDS, TH, EC, COD, BOD and ph was taken forground water, grey water and industrial water. Figure 1.Schematic diagram of Electrocoagulation Cell The setup was made to run for 10,20 and 30 minutes with a DC power supply with desired current density of 3-12V(Fig. 1). This process consists of stainless steel electrode as anode and cathode. As the setup is switched ON the setup starts to run and with 30 mins of interval some depositions of the particles is formed on the electrode. After 30 minutes of 49 editor@iaeme.com

4 Treating Waste Water Using Electrocoagulation Approach interval the sample is taken for post treatment of water sample and water samples were analyzed for different electric potential (3V-12V) 4. RESULTS AND DISCUSSION The Table 1 shows the pre-treatment and post-treatment results of groundwater (Sample 1), grey water (Sample 2) and industrial water collected from textile industry (Sample 3).The following parameters namely (TDS, TH, ph, BOD, COD, and EC) were considered for the analysis according to the procedure of APHA standards. Figure 2 ph and TDS variation in pre (BT) and post (AT) treatment process Figure 3 TH and BOD variation in pre (BT) and post (AT) treatment process Figure 2-4 shows the variations in ph, TDS, TH, BOD, COD and EC during pre (BT) and post (AT) treatment process. It is inferred that electrochemical coagulation using stainless steel electrodes is highly advantageous for the removal of BOD and COD than other parameters. Among all the tested samples, sample 2(grey water) and sample 3 (Industrial water) contain significant amount of BOD and COD. Figure 5 shows the BOD and COD removal in different 50 editor@iaeme.com

5 S. Packialakshmi, P.M. Bhawani No Figure 4 COD and EC variation in pre (BT) and post (AT) treatment process Table 1 Characteristics of different sources of water in pre and post treatment PARAMETERS ph 25 C Total Dissolved Solids Total Hardness as CaCO3 BOD (3 days/27ºc) Units Sample1 (Ground water) Sample2 (Grey water) Sample3 (Ind. Water) BT AT BT AT BT AT mg/l mg/l mg/l BDL BDL COD mg/l BDL BDL EC Micro Siemens/cm Figure 5 Removal of BOD and COD for different electric potential and concentration time 51 editor@iaeme.com

6 Treating Waste Water Using Electrocoagulation Approach Characteristics Table 2 Percentage removal of BOD and COD Grey Water Ind Water % Removal BT AT BT AT % Removal BOD(mg/l) COD (mg/l) Different concentration time and electric potential. By comparing all the values, the concentration time of 30 minutes with 12V achieved the optimum values. Table 2 shows the removal efficiency of COD and BOD for grey water and industrial waste water. The highest removal efficiency under optimum operating condition for COD and BOD removal were obtained with 58% and 67% in grey water sample whereas in industrial waste water sample, the efficiencies are 53% and 57%. Further, the study suggested the various simulations in the operating parameters with the economic considerations in order to optimize the above findings. 5. CONCLUSIONS The present study investigated the treatment technique of electrochemical coagulation by testing the samples of Groundwater, Grey water and Industrial waste water. The Electrochemical cell which contains Stainless Steel Electrodes of 3V-12V with minutes concentration time employed for the treatment. The highest removal efficiency under optimum operating condition for COD and BOD removal were obtained with 58% and 67% in grey water sample whereas in industrial waste water sample, the efficiencies are 53% and 57%. Further, the study suggested that different dimensions and spacing of electrodes may improve the values further and the identified technique is feasible for treating the waste water which contains potential organic loading especially for primary treatment. REFERENCES [1] Gracia lara, Montero Ocampo, Treatment of printing and dyeing wastewater by DC electro coagulation Method. Environ. Sci. Tech., 33, 2014, [2] Helen Mohrabhiheravi, Recycling System of Rinsing Process, Water and Wastewater, No.9, Vol. 41, [3] N Kumar swamy, Pratibha Singh, Treatment of dairy effluents by electrocoagulation using aluminium electrodes. Sci. Total Environ., 408, 2013, [4] N Murthy, H.B Rekha, Electrochemical Wastewater Treatment Directly Powered by Photovoltaic Panels: Electro oxidation of a Dye- Containing Wastewater. Environ. Sci. Technol. 44(13), 2011, [5] Namarata S Gajjar, Neha Patel, Treatment of the industrial wastewaters by electrocoagulation: Optimization of coupled electrochemical sedimentation processes. Desalination, 261, 2011, [6] N B Patel and Sony, Electrocoagulation in a packed bed reactor-complete treatment of color and COD from real textile wastewater. Journal of Environmental Management, 123, 2014, XBSZ htm. [7] Abdurrahman Akyol, Treatment of paint manufacturing wastewater by electrocoagulation 52 editor@iaeme.com

7 S. Packialakshmi, P.M. Bhawani [8] Desalination, Vol 285, 2012, pp [9] Feryal Akbal, Selva Camci, Treatment of metal plating wastewater by electrocoagulation, Environmental Progress and Sustainable Eneregy, Vol. 31(3), 2012, , [10] Thirugnanasambandham Karichappan, SivakumarVenkatachalam, and PrakashMaran Jeganathan, Optimization of electrocoagulation process to treat grey wastewater in batch mode using response surface methodology, J Environ Health Sci Eng. 2014; 12: 29.doi: / X [11] Daina kliaugitae; Yasadi, Kamuran; Euverink, Gerrit; Bijmans, Martijn F.M.(2013), Electrochemical removal and recovery of humic-like substances from wastewater,separation and Purification Technology DOI: /j.seppur [12] Diana kliaugitae, kamuran.m, yasadibfaual, An Effective Electrochemical Cr(VI) Removal Contained in Electroplating Industry Wastewater and the Chemical Characterization of the Sludge Produced. Ind. Eng. Chem. Res, 51, 2014, editor@iaeme.com