BIOLOGICAL TREATMENT OF HYDROCARBON COMPOUNDS IN OIL REFINERY WASTE WATER

Three types of microorganisms are used in this study to show the difference between their ability in consumption of the hydrocarbon residual in the industrial waste water of the Al-Doura refinery. These types are: Protozoa (taken from Al-Doura refinery) and two local isolates: P. aeruginosa and P. fluorescens. These have been already tested boichemically, physiologically and according to API 20E system method. Box-Wilson method is used to find the mathematical relations between the variables (temperature, pH and inoculate amount) with biomass amount during the hydrocarbon residual consumption. The obtained experimental results are fitted to a polynomial function of second order. The experiments are carried out using batch culture for both the three isolates (Protozoa, P. aeruginosa, P. fluorescens) and the mixed isolates (P. aeruginosa+ P. fluorescens). The best incubation period for the three isolates is 72 hours. the optimum operation conditions for mixed isolated are biomass 5.22 g/L, BOD5 15 mg/L, TSS 95 mg/L, TDS 4500 mg/L and S.T 25 m.N/m. These results have show that mixed isolates are the best for consumption of hydrocarbon residuals.