Use of claydite-immobilized oil-oxidizing microbial cells for purification of water from oil

Abstract

Oil-oxidizing bacteria were isolated from oil-polluted soil and water samples and identified as Acinetobacter calcoaceticus K-4, Nocardia vacсinii K-8, Rhodococcus erythropolis EK-1, and Mycobacterium sp. K-2. It was found that immobilization of the bacteria on an expanded clay aggregate accelerated their growth and consumption of hydrocarbon substrates. It was also found that water polluted with 100 mg/l oil could be purified with Rhodococcus erythropolis EK-1 and Nocardia vacсinii K-8 cells immobilized in this way. The dependence of the degree of water purification on its flow rate, aeration, and availability of nitrogen and phosphorus sources was determined. The efficiency of water purification from oil by immobilized Rhodococcus erythropolis EK-1 cells at high flow rates (of up to 0.68 l/h), low aeration (of 0.1 l/l per min) and an intermittent supply of 0.01% diammonium phosphate reached 99.5–99.8%.