Development of an accelerated anaerobic process

Abstract

Anaerobic activated sludge process or anaerobic contact process, as it is called by some authors, is a very effective treatment process because it decreases the duration of the decomposition. The only handicap of this process however, is the poor sludge settling due to gas bubbles in the anaerobic sludge. This handicap was overcame in this study by exerting pressure on the sludge. Under these conditions it has been seen that anaerobic sludge could effectively settle. The set-up used in the study consisted of an activated sludge unit, four anaerobic digesters, four gas containers, and four pressure apply systems which were used as settling tanks. All the experiments were carried out at 35C. Aerobic sludge and a strong brewery wastewater was treated with anaerobic activated sludge process using a pressure of 10 m height of water in the settling tanks. When using aerobic sludge as feed with a HRT of 8 days and a loading of 4.5 kg TVS/(day.m3) an efficiency of 64 percent TVS reduction was obtained. In case of hrewery wastewater with an influent of 4800 mg/L COD and a HRT of 4 days, a COD removal efficiency of 88 percent was obtained. It is believed that efficiencies could be increased by improving some operational parameters. In the study, some other experiments were carried out to determine the settling characteristics of anaerobic sludge, and the performance of anaerobic process under different pressures.