Cosmetic wastewater treatment with combined light/Fe0/H2O2 process coupled with activated sludge

Wastewater from a cosmetic factory, with an initial chemical oxygen demand (COD) of 1140 mg/L, was treated using a combined light/Fe-0/H2O2 process followed by biological treatment. The light/Fe-0/H2O2 process, with 1000/2280 mg/L Fe-0/H2O2 doses and 120 min process time, resulted in 70% COD removal, to final COD of 341 mg/L. The chemically treated wastewater was successfully subjected to biological treatment in a sequencing batch reactor (SBR), with up to 20% volume fraction in the influent, without significant deterioration of COD, nitrogen and phosphorus removal, but with possible small negative effects on polyphosphate accumulating organisms (PAOs), nitrifiers and other bacteria present in the microbial community. The COD of the effluent was in the range of 14-28 mg/L, resulting in overall COD removal of up to 97.7%. Untreated cosmetic wastewater, subjected to biological treatment in SBR, caused crucial changes in the microbial community structure, leading to a significant decrease in the efficiency of organic carbon, nitrogen and phosphorus removal.