Effect of Organic Load of Refinery Wastewater in Municipal Wastewater Treatment using Bench Scale Extended Aeration Activated Sludge System

Petroleum refinery wastewater has the characteristic of high concentration of
aliphatic and aromatic petroleum hydrocarbons, which could lead to heavy
pollution to the environment. In this study, petroleum refinery wastewater was
co-treated with municipal wastewater in a continuous flow bench scale reactors.
Two bench scale reactors, A and B each of liquid volume of 18 L treats
municipal wastewater and a mixture of municipal and refinery wastewater,
respectively. The flow rate, Q for both reactors was maintained at 9 L/day with
the hydraulic retention time (HRT) and sludge retention time (SRT), set at 2 days
and 40 days, respectively. Food to microorganism (F/M) ratio, concentration of
effluent soluble chemical oxygen demand (sCOD), mixed liquor suspended
solids (MLSS), and mixed liquor volatile suspended solids (MLVSS) were
monitored throughout the study period. The result of a full five months operation
show high removal efficiencies of organic matter of about 90% as sCOD with
30% loading of the refinery wastewater.
Keywords: Continuous flow, Organic loading, Refinery wastewater, Extended
aeration, Biological treatment, Activated sludge