Remediation of ammonia-stripped sanitary landfill leachate by integrated heterogeneous Fenton process and aerobic biological methods

Abstract

ABSTRACT The use of heterogeneous Fenton process combined with biological and physical treatment of sanitary landfill leachate has been evaluated. Leachate used in this study was collected from the drainage system of a landfill in Borg El-Arab city – Egypt. As a pre-treatment step, the collected leachate was subjected to ammonia stripping at pH 10.0 for 6 h to reduce the ammonia toxicity for the subsequent biological treatment steps. In this step, over 80% of the ammonia content of the leachate could be removed. Then, the ammonia-stripped leachate was subjected to heterogeneous Fenton process or to aerobic biological treatment. At its optimum operating conditions namely; 37.18 g/L H2O2, 5 g/L catalyst and a reaction time of 4 h, the use of heterogeneous Fenton process achieved COD removal up to 73%. Corresponding COD removal obtained after biological treatment was 68%. To select the best sequence of the treatment steps, the ammonia-stripped sanitary landfill leachate was subjected to two treatment trains. The first one was biological treatment followed by heterogeneous Fenton process; while, the second was heterogeneous Fenton process followed by biological treatment. The highest reductions of the organic compounds and ammonia were achieved after using biological treatment followed by the heterogeneous Fenton process. The use of this treatment configuration achieved total COD, BOD and NH4-N removals of 88%, 84% and 96% respectively. Accordingly, the proposed treatment train can be considered effective in the treatment of landfill leachate and environmental protection.