ASSESSING THE TOXICITY OF PRODUCTS OBTAINED BY INTERTIZING OIL SLUDGE WITH POLYMER WASTES
The oil production and refining waste (oil sludge) management problem is relevant now. This paper gives a brief description of advantages and disadvantages of thermal, chemical, physicochemical and biological methods of oil sludge management. The conclusion is drawn that the above methods are destructive and may give a boost to destroying valuable components contained in oil sludge. A method is proposed to process oil sludge using inertisation by mixing with other wastes from other process units. The chemical group composition of the oil sludge formed at CJSC PC Eco+ has been calibrated. Aromatic hydrocarbons and resins are found to predominate in its composition. The oil sludge was recovered to produce a composite by mixing it with various polymer wastes, such as polypropylene and high/low pressure polyethylene, in various proportions. The best physical and mechanical parameters are found to be achieved when mixing the oil sludge with polymer wastes at a ratio of 5:1. Some physical and mechanical characteristics were identified for the products of oil sludge inertisation with polymer wastes. The content of oil products and mineral salts in water extracts obtained from the resulting composites was identified using standard techniques. The content of water-soluble hydrocarbons in water extracts from the resulting composites was found to be 0.01-0.02 mg/dm3, and that of mineral salts was 0.001-0.002 mg/dm3. The toxicity of water extracts from the oil sludge inertized by polymer wastes was initially assessed using garden cress seeds. The water extracts were found not to provide any toxic effect on the germination of garden cress seeds, even contributing to some increase in the length of the germinal roots and of the sample plant shoots. The toxicity of water extracts from the oil sludge inertized by low-pressure polyethylene wastes was assessed using standard test objects Daphnia magna Straus and Paramecium caudatum. The reciprocal dilution of the water extracts is found to be 35.46 and 6.92, respectively, which complies with the low hazard (category 4) of the product obtained. The composite obtained by mixing the oil sludge with low-pressure polyethylene at a ratio of 5:1 is suggested to be used in manufacturing constructional or asphalt-bitumen compositions.