PROBLEMS OF SOAPSTOCK TREATMENT OF VEGETABLE OIL PRODUCTIONS AND THEIR SOLUTIONS

Abstract

Wastewater generated during vegetable oil production contains various pollutants that enter it during soapstock processing: fats and fatty acids and their salts (aqueous soap solutions), glycerin, phosphoglycerates, neutral fat, phosphatides, proteins, carbohydrates, dyes, unsaponifiable and waxy substances, salts, mechanical impurities, etc. Aim. The purpose of the work was to study the processes of purification of industrial wastewater from oil production and to propose an effective technology for their treatment, taking into account the regulatory requirements for the discharge of treated wastewater into the city sewage system. Methods. Chemical oxygen demand (COD) was determined by the dichromate method. The concentration of suspended solids was determined by gravimetric method. Results. As a result of research, calcium carbonate was chosen as an alkaline reagent. After treatment of soapstock with calcium carbonate followed by flotation, the effect of removing the suspended particles was 70–75%, and COD decreased by 60%. On the basis of the research, a technology for processing soapstock was proposed, including sequential processes of physicochemical wastewater treatment —averaging, alkalization with calcium carbonate, stage I of flotation, coagulation, stage II of flotation, oxidation with hydrogen peroxide, filtration through quartz filters and adsorption on carbon filters. Conclusion. An effective technology for preliminary cleaning of the soapstocks oil production has been developed. This will significantly reduce the concentration of organic matter and other pollutants in soapstocks, which will significantly reduce the impact of such effluents on the processes of biological wastewater treatment of urban wastewater treatment plants.