Abstract
In this study, effective biological treatment of wastewater from heavy oil recovery was developed by (1) utilizing microorganisms with high oil-degrading ability, (2) allowing greater organic loads while increasing both process stability and the resistance to shock loading, (3) minimizing the production of waste sludge byproducts, and (4) adopting anaerobic and aerobic biological processes to improve the biodegradation of wastewater. Fixed-film bioreactors at 15-hr hydraulic retention time decreased chemical oxygen demand by 74.8%, total suspended solids by 90.9%, oil by 80.6%, and phenols and sulfides by 100%. The results of an in situ pilot system showed that the bioreactor's hydrolytic acidulation and contact oxidation tanks were suitable for treating oilfield wastewater and that water quality after treatment fully met national drainage standards.