Optimization of process parameters in coagulation of landfill leachate by Al2(SO4)3 and PACl

Abstract

In this study, landfill leachate treatment by coagulation and optimization of process parameters were aimed. Alum (Al2(SO4)3) and Poly Aluminum Chloride (PACl) were used as coagulants to remove total suspended solids (TSS) from landfill leachate, and coagulant dose, reaction time, and pH were optimized as process variables. The Box-Behnken, one of the response surface methodology designs, was used in modeling the coagulation process. The R2 values were very high (>95%) for TSS removal and the models were sufficiently in good agreement with experimental results. The TSS removal efficiencies in coagulation processes with alum and PACl under optimum process conditions determined by the model were 62.1% and 76.4%, respectively while the experimental values under optimum operating conditions were 60.8% and 75.1% in alum and PACl coagulation processes, respectively. According to the results of the study, both coagulation processes were effective in TSS removal from landfill leachate, and response surface methodology is a useful tool for optimizing the treatment parameters. The removal efficiency of the coagulation process conducted with PACl is higher than that of the alum process. Thus, it can be inferred that PACl is more effective under optimized conditions in this study.