Effect of persulfate and persulfate/H_2O_2 on biodegradability of an anaerobic stabilized landfill leachate

摘要

The current study investigated the effects of S_2O_8~(2-) and S_2O_8~(2-)/H_2O_2 oxidation processes on the biodegradable characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46% after S_2O_8~(2-) oxidation (using 4.2 g S_2O_8~(2-)/1 g COD_0, at pH 7, for 60 min reaction time and at 350 rpm shaking speed), and improved to 81% following S_2O_8~(2-)/H_2O_2 oxidation process (using 5.88 g S_2O_8~(2-) dosage, 8.63 g H_2O_2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of BOD_5/COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S_2O_8~(2-) and S_2O_8~(2-)/H_2O_2 oxidation processes, respectively. The fractions of COD were determined before and after each oxidation processes (S_2O_8~(2-) and S_2O_8~(2-)/H_2O_2). The fraction of biodegradable COD_((bi)) increased from 36% in raw leachate to 57% and 68% after applying S_2O_8~(2-) and S_2O_8~(2-)/H_2O_2 oxidation, respectively. As for soluble COD_((s)), its removal efficiency was 39% and 78% following S_2O_8~(2-) and S_2O_8~(2-)/H_2O_2 oxidation, respectively. The maximum removal for particulate COD was 94% and was obtained after 120 min of S_2O_8~(2-)/H_2O_2 oxidation. As a conclusion, S_2O_8~(2-)/H_2O_2 oxidation could be an efficient method for improving the biodegradability of anaerobic stabilized leachate.