Can electrocoagulation be an effective post-treatment option for SBR treated landfill leachate and municipal wastewater mixture?

Abstract

Abstract A combined process of sequencing batch reactor (SBR) and electrocoagulation for co-treatment of landfill leachate and municipal wastewater was assessed. SBR was used in the first instance for co-treatment of 20% (v/v) landfill leachate and municipal wastewater mixture. Effluent from SBR was subjected to electrocoagulation for post-treatment, with aluminum as sacrificial anode and stainless steel as cathode. Direct current at a density of 257 A/m2 was applied during the electrocoagulation process. In electrocoagulation, spacing between the two electrodes was varied at 5 and 7 cm to assess its influence on treatment efficiency. SBR was effective to remove 65% chemical oxygen demand (COD), 77% total suspended solids (TSS), 89% ammonia, 80% nitrate, 64% phosphate and post-treatment by electrocoagulation resulted in an overall 98% COD, 98% TSS and 99% ammonia, nitrate and phosphate reduction efficiency with 5 cm of electrode spacing. Respectively, final COD, ammonia and TSS was 37, 1 and 98 mg/L after 150 min of electrocoagulation which met the Indian standards for the discharge of treated wastewater. The results highlight that SBR followed by electrocoagulation as post-treatment can be an effective option for the treatment of landfill leachate and municipal wastewater mixture.