Lab-scale optimization of propylene glycol removal from synthetic wastewater using activated sludge reactor

Propylene glycol (PG) is not a toxic matter. However, it can dramatically increase BOD of water resources and that is why removal of PG is important. Removal of PG in synthetic wastewater was studied in a continuous activated sludge pilot-scale reactor. The influence of various factors (pH, nitrogen source, COD and wastewater feed salinity (conductivity)) on micro-organism growth as a measure of removal was determined, and the optimum condition for maximizing this response was obtained using Taguchi experimental design method. Primary micro-organisms were obtained from the return sludge line of the Shahrak-Gharb wastewater treatment system located in the city of Tehran. The micro-organisms have been adapted to high organic loads during five stages in 119 days. The maximum PG removal efficiency was equal to 85%. In the selected range of levels, the best pH was equal to 8 and the influent COD was 1300 mg/L. The best nitrogen source was urea, and salinity was obtained equal to 8%.