Comparison of several combined/integrated biological-AOPs setups for the treatment of municipal landfill leachate: Minimization of operating costs and effluent toxicity

Abstract The treatment of medium-age landfill leachate was investigated by employing several set-ups including a sequencing batch biofilter granular reactor (SBBGR) step, with or without ozone enhancement, followed or not by a polishing stage with solar photo-Fenton (SphF). Objectives of the investigation were to compare different treatment strategies in order to achieve the lowest operating cost and to reduce the toxicity of the final effluent, evaluated by three different tests (respirometry, Vibrio fischeri and Lepidium sativum phytotoxicity). These objectives were addressed for two different target COD values, namely 160 and 500 mg/L, to be met in the final effluent for disposing of to water bodies and to sewers, respectively, requested by Italian environmental regulation. The different treatment strategies have demonstrated to be technically suitable for achieving the requested COD (160 or 500 mg/L) and reduction of the initial toxicity goals. For the COD target of 500 mg/L, the investigated treatment set-ups proposed in this paper showed to have comparable operating cost ( 3.2 € / m inf. 3 ). Instead, when the target COD is 160 mg/L, the combination SBBGR + SphF is economically more convenient ( 4.1 € / m inf. 3 ) being the operating cost of the other two investigated treatment set-ups (SBBGR/O3 and SBBGR/O3 + SphF) 5.7 and 4.8 € / m inf. 3 , respectively. As far as toxicity reduction is concerned, for both the COD target of 500 and 160 mg/L, the SBBGR/O3 set-up gave better results than other investigated treatment options.