Combined treatment of high-strength fresh leachate from municipal solid waste landfill using coagulation-flocculation and fixed bed upflow anaerobic filter

The current research study describes the coagulation-flocculation process's investigation, followed by biological treatment. The two landfill simulated reactors were fabricated using an iron sheet of 1 m × 1 m × 1.1 m. In this study, landfill reactors were simulated with different operation modes, i. e., Reactor1 (R1) was operated without rainfall, and reactor2 (R2) Operated at the weighted average actual rainfall rate of 50 years, while both contained the waste composition of wet waste (73%) and dry waste (27%). The type of landfill leachate used for the study was fresh/young leachate. Initially, R1 leachate was used to obtain the effective coagulant in terms of coagulant dose and pH using different conventional coagulants, i.e., potash alum KAI(SO₄)₂·12H₂O, ferric chloride (FeCl 3 ), ferrous sulphate heptahydrate (FeSO 4 ·7H 2 O), calcium hydroxide (Ca(OH) 2 ) and bentonite clay. R1 leachate was used for the acclimatization phase for biomass growth, and R2 leachate was used for the treatment phase to check the removal efficiency of varied concentrations of pollution indicator parameters of leachate in the anaerobic filter. The leachate (R1) was characterized before the pretreatment process and showed that the chemical oxygen demand (COD) removal percentage was higher for FeCl 3 with 55.4% at pH 5. In the up-flow anaerobic filter's acclimatization phase, maximum COD removal was 23.3%, while in the treatment phase, it was 20.03% (23,170 mg/L) removal of COD for the leachate from the simulated rainfall reactor (R2). R2 leachate was characterized before using it for the treatment phase. COD's removal efficiency was 35% in coagulation treatment, only 20.03% was achieved in the anaerobic filter, and overall removal was 51.52%, including both the treatment technologies. Therefore, it can be concluded from the study that there was no significant COD removal in the anaerobic filter through the conventional way. A further recommendation is to provide a microbial source (seeding) for biomass growth to improve anaerobic filter efficiency.