Concentrated landfill leachate treatment with a combined system including electro-ozonation and composite adsorbent augmented sequencing batch reactor process

Abstract

Abstract A large volume of concentrated leachate is generated from leachate treatment via reverse osmosis. Concentrated leachate is a dark brown solution with high levels of pollutants. Treating concentrated leachate is extremely difficult, and thus, a combined treatment system is suggested. In the present study, concentrated landfill leachate was treated using a combined treatment technique that included electro-ozonation and a composite adsorbent augmented sequencing batch reactor (SBR) process. Central composite design and response surface methodology were utilized to investigate experimental data. Reaction time (30–120 min) and ozone concentration (40–120 mg/L) were selected as the independent variables. At an optimum reaction time (96.9 min) and ozone dosage (120.0 mg/L), the removal efficacies of chemical oxygen demand (COD), color, and nickel were 64.8%, 90.4%, and 52.9%, respectively, at original pH (7.3), as well as current and voltage of 4 A and 9 V, respectively. Ozone utilization ranged from 0.3 kg to 1.4 kg COD removed per kg ozone consumed. After treatment at optimum electro-ozonation performance, concentrated leachate was transferred to the powdered composite adsorbent (P-BAZLSC) augmented SBR reactor (PB-SBR). PB-SBR improved the removal efficiency for COD, color, and nickel from 64.8% to 88.2%, from 90.4% to 96.1%, and from 52.9% to 73.4%, respectively.