The Use of Biotreatment Technology to Dispose of Offshore Drilling Waste Oily Fluids

Abstract

Disposing of oil-based drilling fluid with biotreatment technology has many advantages: it is only 30-50% of the expense of conventional chemical or physical processing technologies, has a low impact on the environment, with no secondary pollution, and utilizes local control and entails simple operations. After a series of collection, isolation, purification, cultivation and domestication of petroleum degrading bacterial, three strains were obtained that can effectively degrade petroleum hydrocarbons. The growth of the bacterial strains and the consequent crude oil degradation were found to be at the greatest rates using the following biochemical processing conditions. The strains were grown in ammonium nitrate and a small quantity of yeast powder at a temperature of 50°C and pH of 6.0. The strain quantity was 2%, and the rotating speed of the shaker was 180rpm. The biochemical disposal process and laboratory-scale simulation of processing devices of oil-based drilling fluid were also designed. The oil content of disposed oily waste mud generally was generally less than 2mg/L, and the degradability of the waste was over 98%. The performance index meets the requirement of the China’s offshore wastewater discharge standards.