Continuous cultivation of Debaryomyces hansenii (LAF‐3 10 U) on dodecane in synthetic desalter effluent at varying dilution rates on dodecane

Abstract

Desalter effluent (DE) is typically discharged into a petroleum wastewater treatment plant, but its high salt concentration deteriorates the biological treatment. This study used various dilution rates to investigate the treatment of a synthetic DE containing dodecane under saline conditions using a halotolerant yeast, Debaryomyces hansenii, to determine the optimum substrate concentration for use in continuous stirred‐tank reactors (CSTRs). A literature review indicated that this study was the first to examine the biological treatment of DE using D. hansenii in a CSTR system. At a low dodecane substrate concentration, DE did not inhibit D. hansenii growth, and the experimental data approached the Monod model, with μmax and Ks selected as 0.08 h−1 and 1575 mg L−1, respectively. The optimum removal of chemical oxygen demand (95.7% and 85%) was obtained at dilution rates of 0.007 and 0.026 d−1. Using D. hansenii in a CSTR system appeared to be a sustainable approach for the biological treatment of DE. Scale‐up of these laboratory findings to the industrial scale is required to confirm that petroleum DE can be treated using equalization and filtration tanks as a continuous bioreactor. Adjusting the dilution rate can provide sufficient time for biodegradation and hydrocarbon removal from high salt DE by halotolerant yeasts like D. hansenii.