Biological treatment of oilfield-produced water: A field pilot study

A field test was conducted on a hydrolysis acidification/bio-contact oxidation system (HA/BCO) to treat oilfield-produced water with high salinity. By operating the biodegradation system for three months with a hydraulic retention time (HRT) of 32 h and a volumetric load of 0.28 kg COD m3 d−1, the treatment process achieved mean removal efficiencies of 63.5% for chemical oxygen demand (COD), 45% for NH3-N, 79.5% for total suspended solid (TSS), and 68.0% for total petroleum hydrocarbon (TPH). GC/MS was used to analyze relative changes of components of main organic waste in a process indicating that the influent wastewater contained organic compounds from C12H26 to C35H72, which could be degraded effectively with the coordinated action of hydrolysis acidification and aerobic treatment. The use of maize powder can enhance environmental adaptability of microorganisms and biodegradation ability and is recommended as a nutrient supplement to maintain good treatment performance.