Reusability of Fenton Sludge to Reduce COD and Color on Palm Oil Mill Secondary Effluent (POMSE)

This paper reports on the reusability of iron sludge generated from the solar Fenton oxidation on Palm Oil Mill Secondary Effluent (POMSE) samples. The aim of this study was to observe the reusability of Fenton sludge to be used as iron sources for reducing the COD and color of POMSE. The feasibility of iron sludge was determined by recycling the iron sludge five times. Result showed that the percentage removal of COD and color was generally reduced from fresh iron used (F1) to Recycled 1 (R1) and eventually Recycle 5 (R5). The percentage removal of COD for F1, R1, R2, R3, R4, and R5 were 83.8%, 71.2%, 40.3%, 45.1%, 39% and 35.9% respectively. Meanwhile the color removal for F1-R5 were 97.18%, 87.29%, 75.33%, 73.08%, 68.60% and 70.84% respectively. The amount of ferrous iron and total iron in supernatant however, fluctuated between 0.00 to 0.37 and 2.86 to 9.24mg/L respectively. Amount of iron that remained in the sludge in every cycle starting from F1 to R5 were 7271, 7404, 7275, 7546, 7238 and 7025mg iron/kg sludge respectively. In conclusion, it was justifiable to recycle Fenton sludge as a high amount of iron remained even after the fifth time of recycling.