Monitoring of experimental landfill cells with membrane concentrate infiltration: A systematic assessment of leachate quality and treatment performance

The present study investigates the impacts of reverse osmosis concentrate (ROC) infiltration on the leachate quality and treatment performance. Simulated landfill cells were constructed and monitored for 254 days. In-tegrated leachate samples were treated using a reverse osmosis (RO) system to assess changes in leachate quality on membrane fouling and effluent ecotoxicity. Our findings showed that concentrate infiltration increased the leachate's organic content and recalcitrance. The pollution parameters' median values were higher in leachates drained from cells that operated with ROC recirculation (i.e., 6729 vs 1367 mg L-1 [chemical oxygen demand, COD], 33.39 vs 17.39 cm-1 [absorbance at 254 nm, UV254]; p-value < 0.05). Membrane fouling resistance was 6 -fold higher when the RO system was used to treat the methanogenic leachates generated by cells operating at ROC infiltration mode. The ecotoxicological assessment using Vibrio fischeri bacteria indicated that membrane concentrate recirculation increases leachate ecotoxicity and decreases its removal efficiency by RO treatment. The current research provides information to re-examine the recirculation practice of leachate concentrate streams. Recommendations and research prospects are drawn in this context.