Treatment of landfill leachate by membrane processes of nanofiltration and reverse osmosis

Landfill leachate from Jakuevec, Zagreb, Croatia was treated by membrane processes of nanofiltration (NF) and reverse osmosis (RO). Different types of membranes were selected to obtain the parameters of leachate contaminants below maximum concentration levels (MCLs), defined by the Croatian law and EU directive. As a pretreatment of landfill leachate, coagulation and filtration were used. Parameters of total carbon, total organic carbon (TOC), inorganic carbon, chemical oxygen demand (COD), pH, turbidity, conductivity, concentration of different inorganic ions, heavy metals, etc., were analyzed in all steps. The landfill leachate was relatively low loaded with organic substances and ammonia; COD, TOC, and NH4+-N of real sample were 1,720.0mgOL(-1), 1,260.5mgCL(-1), and 1,147.6mgL(-1), respectively. Their concentrations decreased after coagulation for 27.9, 58.6, and 7.9%, respectively. RO/NF membranes (NF270, NF90, and XLE) additionally decreased COD and TOC for >94.6% and >92.5%, respectively. Ammonium ions decreased in the range of 37.1% (NF270)-88.9% (XLE).