ELECTROLYTICTREATMENT OF PALM OIL MILL EFFLUENT

Abstract

An innovative method of palm oil mill effluent treatment was developed based on electrochemical
 oxidation process. 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 palm oil mill effluent. The electrochemical oxidations
 were carried out for varying influent COD concentrations namely 7,000; 10,000 and 15,000 mg/L. For an
 influent COD concentration of 7,000 mg/L at an initial pH of 3.6 ± 0.1; current density of 37.6 mA/cm2;
 sodium chloride content of 3% and at an electrolysis period of 240 min, resulted in the following residual
 concentrations of pH 6.9; COD 114 mg/L; BOD5 73 mg/L; TOC 56 mg/L; residual total chlorine 172 mg/
 L; turbidity 24 NTU and temperature 62ºC respectively. In the case of influent COD concentration of
 15,000 mg/L for the above said operating condition resulted in a residual concentrations of pH 6.5; COD
 2,680 mg/L; BOD5 1,265 mg/L; TOC 1,024 mg/L; residual total chlorine 86 mg/L; turbidity 1,157 NTU
 and temperature 61ºC respectively. The energy requirement were also investigated for an influent COD
 concentration of 7,000 mg/L at 2 and 3% sodium chloride concentration at a fixed current density of 37.6
 mA/cm2. The results showed that at 2 and 3% sodium chloride content for achieving a COD removal
 efficiency of 90%, the energy requirement were found to be 32 and 17 Wh/L respectively. The observed
 energy difference was due to the improved conductivity at 3% sodium chloride content.