Treatment of Weak Sewage by Continuous Electrochemical Process using Noble Metal Electrodes

In this study, both bench- and pilot-scale electrochemical processes adopting copper electrode were used for the treatment of weak sewage in small-scale communities. Considerable organics removal could be achieved during very shorter detention time of 2 similar to 3 minutes by continuous electrolysis procedure, and the nitrogen removal was mostly performed at the beginning of the electrolysis. Most phosphorus was also eliminated in the shorter detention time. It seemed that the phosphorus removal could be performed from the orthophosphate into copper hydrogen phosphate (CuHPO4). The pH value also remarkably increased as electrolysis processed by higher concentration of hydroxyl ion through the electrolysis, whereas the pH value decreased to neutral ranges by additional aeration for 2 hours. In particular, total COD and total nitrogen were additionally decreased by aeration. The ORP value was gradually decreased with increasing detention time in both bench- and pilot-scale experiments. The ORP value considerably decreased in the pilot-scale experiment, which means the organics in the wastewater could be removed at more contiguous time and chance for wastewater during the electrolysis procedure.