Advanced landfill leachate treatment with least sludge production using modified Fenton process

This research was undertaken to investigate various operating conditions of Fenton treatment process for minimizing the sludge production and maximizing COD as well as colour removal from landfill leachate. Sample was collected from Matuail landfill site, one of the major landfill sites of Dhaka City Corporation. For optimum pH value of 5 and optimum dosages of Fenton reagents having H2O2/Fe 2+ molar ratio of 1.3 the highest removal of COD and colour were found 68 % and 87 % respectively with massive sludge production of 75%. The COD and colour removal efficiencies with a threestep dosing of reagents were 11 % and 7 % higher respectively with 17 % less sludge production than those with single dosing of individual Fenton treatment process. Also recycling of Fenton sludge enhanced COD removal efficiency by 6 % having similar colour removal efficiency and reduced sludge production significantly by 38%. With all optimum parameters, the highest removal of COD and colour were found 84 % and 93 % respectively with sludge production of 30 % through multiple dosing of Fenton reagents with sludge recirculation. Conversely, pretreatment with extended aeration before Fenton process provided the achievement of 89 % COD and 97 % colour removals having less sludge volume reduction.