Effect of mixing energy on dispersion of oily sludge into water and subsequent micobial biodegradation

Environmental pollution influences scientists to develop methods to treat wastewater. Uncontrolled release of petroleum in a historical oily sludge lagoon is considered as a hazardous issue. Oily sludge in a lagoon contains various type of complex petroleum hydrocarbons (PHC). Therefore, biodegradation has become an important method to treat hydrocarbons in different media, such as a waste lagoon. This research studied the efficiency of applying mixing energy at three speeds (200, 400, and 600 rpm), by using a motor stirrer with a paddle and marine impeller, to West Texas Crude Oil (WTCO ) dispersion in the aqueous phase with the presence of four dispersant applications (Corexit, FFC500, FTT100%, Petroclean). The highest dispersant effectiveness percentage was at 66% at a mixing speed of 400 rpm, with presence of Corexit and using the paddle impeller. Also, the research predicted the energy dissipation rate () W/kg to calculate the mean diameter at equilibrium (D32). Determining whether the Corexit and mixing speed affect microbial degradation activity was part of this research. The highest rate of oil sludge biodegradation occurred with the absence of Corexit after 28 days. The experimental result shows that the mixing speed delayed the biodegradation rate