Electrolytic treatment of latex wastewater K. Vijayaraghavan*, Desa Ahmad, Ahmad Yuzri Ahmad Yazid Department of Biological and Agricultural Engineering, Faculty of Engineering, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Tel. +60 (3) 8946 6416; Fax +60 (3) 8946 6425; email: vijay@eng.upm.edu.my Received 4 October 2006; Accepted 17 May 2007 Abstract A novel method of latex wastewater treatment was developed based on in-situ hypochlorous acid generation. The hypochlorous acid was generated in an undivided electrolytic cell consisting of two sets of graphite as anode and stainless sheets as cathode. The generated hypochlorous acid served as an oxidizing agent to destroy the organic present in the latex wastewater. For an influent COD concentration of 3,820 mg/L at an initial pH 4.5; current density of 74.5 mA/cm 2 ; sodium chloride content 3% and electrolysis period of 90 min, resulted in the following residual concentration pH 7.3; COD 78 mg/L; BOD 5 55 mg/L; TOC 45 mg/L; residual total chlorine 136 mg/L; turbidity 17 NTU and temperature 54EC, respectively. In the case of 2% sodium chloride content for the above, said operating condition resulted in a residual concentration of pH 7; COD 162 mg/L; BOD 5 105 mg/L; TOC 90 mg/L; residual total chlorine 122 mg/L; turbidity 26 NTU and temperature 60EC respectively. The energy requirements were found to be 35 and 50 Wh/L while treating 24 L of latex wastewater at 3 and 2% sodium chloride concentration at a current density 74.5 mA/cm 2 . The observed energy difference was due to the improved conductivity at high sodium chloride content. Keywords: Electrolytic treatment; Latex wastewater; Hypochlorous acid; Chlorine, Rubber wastewater, Electro- chemical treatment 1. Introduction Until the 1980s the agro-based industrial sector played a very significant role in Malaysia’s economy. However, in the mid-80s, large tracts *Corresponding author. commercial and residential uses. The above changing scenario in the last two decades was responsible for a gradual decline in raw natural rubber production, and Malaysia lost its position as the world’s largest natural rubber producer which it held for the past many decades. Pre- sently, Malaysia is the fourth largest rubber producer in the world — after Thailand, Desalination 219 (2008) 214–221 0011-9164/08/$– See front matter © 2008 Published by Elsevier B.V. of rubber land were converted for industrial, doi:10.1016/j.desal.2007.05.014