Study on New Method of Microorganism Acclimation for Biological Treatment of High-Salinity Oilfield Wastewater

A new method of microorganism acclimation for biological treatment of high-salinity oilfield wastewater was proposed, in which the salinity was increased in logarithmic mode, while in the traditional method the salinity was mainly increased in proportion. A contrast experiments was made between new method and the traditional method. The quality of the influent is as follow: salt content was ranged from 27.4 to 31.8 g L-1, the value of COD ranged from 350 to 640 mg L-1, the petroleum hydrocarbon was 10.5 mg L-1. The COD removal rate, bacteria adaptation rate and petroleum hydrocarbon removal rate of the new method was 82.3%,86.1% and 69.2%, respectively. These value of traditional method was 72.4%, 75.6% and 60.8%, respectively. The activated sludge acclimated by the new method is less vulnerable to high salt concentration and the structures of the sludge are more stable than the sludge acclimated by the traditional method.