Abstract
Methane fermentative bacteria and denitrifying bacteria were enriched with a synthetic medium, and a biofilm was formed on solid support surfaces in a completely mixed reactor. In the medium, glucose, peptone and sodium nitrate were used as carbon and nitrogen sources.
By using the biofilm reactor, characteristics of the anaerobic treatment of an aqueo us mixture of organic matter and nitrate were studied experimentally, and effects of the C/N ratio on removal efficiencies of TOC and nitrate and effluent characteristics were examined in batch wise and/or continuous operations.
Organic m atter and nitrate were removed simultaneously in the anaerobic biofilm reactor, in which methane fermentative bacteria and denitrifying bacteria symbiosed. In the simultaneous treatment, acetate which is an intermediate metabolic product in methane fermentation were effectivelly utilized by denitrifying bacteria as hydrogen donor. Competition between methanogens and denitrifying bacteria existed for the utilization of acetate. Removal efficiencies of TOC and nitrogen for contiuous operations were greater than 94% and 65%, respectively. Both the values of ORP and pH increased with the increment of nitrate concentration. Under high nitrate loading conditions, methane gas production decreased.
