A new treatment step of bioelectrochemically treated leachate using natural clay adsorption towards sustainable leachate treatment

Standalone and combined leachate treatment mechanisms suffer from low treatment efficiencies due to leachate’s complex, toxic, and recalcitrant nature. Bioelectrochemical system (BES) was used for the first time to investigate the treatment of leachate mixed wastewater (WW) (i.e., diluted leachate, DL) (DL ≈ L:WW = 1:4) to minimize these complexities. A natural clay (palygorskite) was used as adsorbent material for further treatment on the BES effluent (EBES) while using two different masses and sizes (i.e., 3 g and 6 g of raw crushed clay (RCC) and 75 μ of sieved clay (75 μSC)). According to bioelectrochemical performance, BES, when operated with low external resistance (R _ext = 1 Ω) (BES 1), showed a high removal of COD and NH₃-N with 28% and 36%, respectively. On the other hand, a high R _ext (100 Ω, BES 100) resulted in low removal of NH₃-N with 10% but revealed high COD removal by 78.26%. Moreover, the 6 g doses of 75 μSC and RCC showed the maximum COD removals of 62% and 38% and showed the maximum removal of NH₃-N with an average range of 40% for both sizes. After efficient desorption, both clay sizes resulted in regeneration performance which was observed with high COD (75%) and NH₃-N (34%) on EBES. Therefore, when BES and clay adsorption technique sequentially treated and achieved with combined removal of ~ 98% for COD and ~ 80% of NH₃-N, it demonstrated an efficient treatment method for DL treatment.