Evaluation of efficiency of activated sludge process with extensive aeration and sludge return in reducing COD of beverage industry effluent

The effluent of the beverage industry has high amounts of organic compounds, and biological treatment methods are very common in this field. By applying efficient methods to treat the effluent of the beverage industry, it is possible to provide the ground for the consumption of treated effluent in other places. The general purpose of the present study is to evaluate the efficiency of the activated sludge process with extensive aeration and sludge return for wastewater treatment of the beverage industry. The present study lasted for 60 days. After making a laboratory pilot, for evaluation, first the pilot was fed with sugar and then synthetic effluent was prepared and transferred to the pilot. The organic load has increased from 1.03 kgCOD/m3.d to 1.93 kgCOD/m3.d. In this study, the COD parameter was used to measure the effluent pollution of the beverage industry and the working cycle was 24 hours. The results of the mentioned process showed that with the final organic loading at the rate of 1.93 kgCOD/m3.d, the removal efficiency was equal to 90%. By examining the hydraulic retention times of 6, 12, 18 and 24 hours, the highest efficiency in the retention time of 24 hours was obtained and in the research process, the pH was between 7 and 9 and the temperature was in the mesophilic range. Therefore, it can be concluded that the process of activated sludge with extensive aeration and sludge return is effective in treating the effluent of beverage industries with medium organic load.