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

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 4A and 9V, 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. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.