Combined processes for wastewater purification: treatment of a typical landfill leachate with a combination of chemical and biological oxidation processes

BACKGROUND Among anthropogenic wastewaters, landfill leachate is known to contain numerous persistent organic pollutants, heavy metals, noxious microorganisms, etc., which makes the establishment of an efficient treatment procedure for leachate a matter of great importance. In this work, municipal waste landfill leachate was subjected to various types of chemical (CHEM) and biological (BIO) treatment with the final aim of establishing an optimal treatment scheme combining of individual physico-chemical and biological processes. RESULTS Three different treatment strategies (CHEM-BIO, BIO-CHEM and BIO-CHEM-BIO) were compared based on biodegradability and removal efficiencies achieved. Due to high initial biodegradability of raw leachate, the most efficient combined process was aerobic biological pre-treatment followed by Fenton treatment and subsequently biological post-treatment. The efficiency of combined treatment processes was investigated at laboratory scale, with over 90% COD and BOD7 removal. Finally, in order to evaluate the economic efficiency of the processes, consumption of Fenton's reagent was compared for CHEM-BIO and BIO-CHEM setups, with the latter achieving three times lower reagent consumption, at the same time providing similar treatment efficiency. CONCLUSIONS A readily-applicable efficient and economically feasible technological solution is provided for the treatment of typical municipal landfill leachate. © 2014 Society of Chemical Industry