Journal of Water Process Engineering 17 (2017) 50–62 Contents lists available at ScienceDirect Journal of Water Process Engineering journa l h om epage: www.elsevier.com/locate/jwpe Treatment of wastewater from sugarcane process industry by electrochemical and chemical process: Aluminum (metal and salt) Omprakash Sahu a,∗ , Dubasi Govardhana Rao a , Richa Gopal b , Anurag Tiwari b , Dharm Pal b a School of Chemical and Food Engineering, BiT Bahir Dar University, Ethiopia b Department of Chemical Engineering, National Institute of Technology, Raipur, India a r t i c l e i n f o Article history: Received 17 May 2016 Received in revised form 13 March 2017 Accepted 16 March 2017 Keywords: Aluminum electrodes Electrocoagulation studies Electrolysis for wastewater treatment Sugar industry wastewaters Wastewater treatment a b s t r a c t The sugarcane processing industry needs a large amount of water. It requires approximately 1.5–2 m 3 of water to process 1 t of sugarcane and generates 1-m 3 as wastewater. The aim of research work is to treat the sugar industry wastewater with electrocoagulation and coagulation process by batch and continuous modes. The results showed that by using aluminum electrode, 84% of COD reduction and 88% of color removal could be achieved at an optimum pH of 7.5, electrode distance of 20 mm, current density of 178 A m −2 and electrolyte concentration of 0.5 M. In continuous treatment, a maximum of 61% of COD and 65% of color removal were achieved. The combined treatment with electrocoagulation and coagulation results showed 98% COD and 99.5% of the color reduction under the optimum condition. The filtrate and sludge were analyzed by FTIR spectroscopy. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Water is a primary life sustaining requisite for all living beings and process industries, without the availability of which it is impos- sible to sustain and operate [1,2]. Due to the large consumption of water in different unit operations, large quantities of effluent waters come as wastewaters. Wastewaters are unserviceable and are generally discharged to nearby surrounding areas through river streams [3]. These unwanted discharges overburden the environ- ment, due to the high percentage of biological and chemical oxygen demands [4]. Many authors have described in literature differ- ent technologies to treat the industrial wastewaters. However, the treatment methods may dependent upon the type of pollutants present in wastewater [5]. Some of them are based on chemi- cal coagulation [6], bio-coagulation [7], filtration [8], ion exchange [9], aerobic and anaerobic treatment [10], advanced oxidation pro- cesses [11,12] etc. Most of them require substantial financial inputs and their use is restricted mainly because of economic consid- erations overriding the importance of pollution control. Among various techniques envisaged, electrolysis is probably the best to treat the wastewater. This technology was first introduced in the United Kingdom in 1889 [41]. Electrochemical treatment with alu- minum and iron metal electrodes was patented in the United State ∗ Corresponding author. E-mail address: ops0121@gmail.com (O. Sahu). in 1909 and applied for drinking water treatment in 1946 [13]. However, in last one decade, this technology has been resurrect- ing and employed vastly in rest of world for treatment of different types of industrial wastewaters. Among them some are like textile dye wastewater [37], pharmaceuticals industry wastewater [14], petrochemical industry wastewater [15], dairy industry wastewa- ter [16], meat industry waste water [17], rice industry wastewater [18], pulp and paper industry wastewater [19] and also sugar indus- try wastewater [20] etc. The electrochemical treatment is based on a simple mechanism in which electric current is applied to the conjugate electrode [21]. The dissolution of electrode material takes place due to electric current, which when applied on external circuit anode material, disintegrates and cathode material favors to complete the inter- nal circuit. The performance of electrocoagulation depends on the nature of wastewater, current supply, the electrolyte used, type and arrangement of the electrode including its operation [22]. The electrochemical treatment can be carried out in both batch and continuous mode, but the efficiency of treatment depends upon the residence time, mixing conditions, flow rate and concentration of pollutants [40]. Generally, in the process industries continu- ous mode of operation is employed due to the large volume of wastewater generating from different operations. Electrochemical treatment apparently is an efficient technology under normal situa- tions when traditional processes fail to achieve the adequate norms. Some other advantages associated with electrochemical treatment processes are it simple arrangement, potential to reduce the pol- http://dx.doi.org/10.1016/j.jwpe.2017.03.005 2214-7144/© 2017 Elsevier Ltd. All rights reserved.