Municipal solid waste landfill leachate treatment by fenton, photo-fenton and fenton-like processes: Effect of some variables

Advanced oxidation processes like fenton and photo-fenton have been effectively applied to oxidize the persistentorganic compounds in solid waste leachate and convert them to unharmful materials and products. however, thereare limited data about application of fenton-like process in leachate treatment. therefore, this study was designedwith the objective of treating municipal landfill leachate by fenton, fenton-like and photo–fenton processes todetermine the effect of different variables, by setting up a pilot system. the used leachate was collected from amunicipal unsanitary landfill in qaem-shahr in the north of iran. fenton and fenton-like processes were conductedby jar-test method. photo-fenton process was performed in a glass photo-reactor. in all processes, h2o2 was usedas the oxidant. feso4.7h2o and fecl3.6h2o were used as reagents. all parameters were measured based onstandard methods. the results showed that the optimum concentration of h2o2 was equal to 5 g/l for thefenton-like process and 3 g/l for the fenton and photo-fenton processes. the optimum ratio of h2o2: fe+2/fe+3were equal to 8:1 in all processes. at optimum conditions, the amount of cod removal was 69.6%, 65.9% and83.2% in fenton, fenton-like and photo–fenton processes, respectively. in addition, optimum ph were 3, 5 and 3and the optimum contact time were 150, 90 and 120 minutes, for fenton, fenton-like and photo–fentonprocesses, respectively. after all processes, the biodegradability (bod5/cod ratio) of the treated leachate wasincreased compared to that of the raw leachate and the highest increase in bod5/cod ratio was observed in thephoto-fenton process. the efficiency of the fenton-like process was overally less than fenton and photo-fentonprocesses, meanwhile the fenton-like process was at higher ph and did not show problems