Performances of various hybrids systems coagulation-ultrafiltration/nanofiltration-reverse osmosis in the treatment of stabilized landfill leachate

To assist resolve issues associated with landfills which may pose a potential environmental threat via discharge of high strength polluted wastewater known as leachate, because of the huge amount of municipal solid waste dumped into landfills. A chain of processes for treating stabilized leachate or landfill leachate (LFL) at laboratory-scale and low costs will be investigated. The treatment system consists of the integration of ultrafiltration (UF) membrane process with coagulation method (Coag-UF) as pretreatment step for treating LFL using a dual nanofiltration (NF) and reverse osmosis (RO) system with the main objective to achieve the Moroccan discharge limits. The results show that the combination of Coag-UF, using ferric chloride FeCl3 as a coagulant, has allowed a significant reduction of LFL pollutants, namely 62% for chemical oxygen demand, 89% for total suspended solids and 62% for iron (Fe) while reducing the fouling phenomena. Also, the results indicate that the Coag-UF/NF/RO hybrid system is able to produce quality water according to directive FAO and water reuse standard for irrigation, land watering in Morocco, with an overall water recovery up to 57.2%, a salt rejection reaches 99% and a low energy cost (0.0019 US $/m(3)) compared to the two others hybrid systems Coag-UF/RO and Coag- UF/NF which their energy cost are 0.0044 and 0.0032 US $/m(3), respectively.