Optimization of the process of anaerobic-aerobic purification of waste waters of food production using the spatial separation of stages

Abstract

The advanced energyand resource saving technologies for purification of industrial waste waters from the food production include both anaerobic biotechnologies, and the combined ones, which include anaerobic and aerobic purification steps. They possess such advantages as economic efficiency, high purification efficiency, minimal formation of excess sludge and ability to obtain alternative energy carrier - biogas. The aim of this investigation was to perform optimization of the process of anaerobic-aerobic biological purification of wastewaters from the milk treatment enterprise. During our investigation we have studied relations between the efficiency of the process of anaerobic-aerobic biological purification of wastewaters of the milk treatment enterprise and specific organic load. We investigated influence of the spatial separation of the anaerobic step of purification with directed succession of the microbial community, which performs the sequence of destruction of the organic compound on the process efficiency. It was shown, that the preliminary anaerobic purification of wastewaters from the milk treatment enterprise allows one to significantly reduce organic load at the aerobic stage of the purification facilities and remove up to 85% of the organic compound. With increase of the specific organic load from 1.4 up to 2.8 kg COD·m -3·days-1 we see a drastic improvement of the efficiency characteristics both for anaerobic and aerobic stages. The redox-potential of the fermentation medium depends on the metabolitic activity of the microbial community and might be used as an efficiency characteristics for destruction of the organic compound at the anaerobic stage, and as an indicator for the oxygen saturation of the medium at the aerobic stage of purification.