Effect of ammonium nitrogen in anaerobic biofilter using live-stock-wastewater

축산폐수의 혐기성 고정법에 있어서 암모니아성 질소의 영향

In this research, the synthetic livestock wastewater was prepared to study the characteristics of organic matter removal, the change of VFA production, and the amount of gas production with respect to the change of ammonium nitrogen concentration in the waste using anaerobic fixed bed process, which is an anaerobic biofilm process. The HRT and operation temperature were 1 day and $35{\pm}1^{\circ}C$, respectively. Also, the characteristics of organic matter removal and the inhibitory effect on microorganism in the anaerobic process were studied on the organic loading and ammonium nitrogen concentration. The results obtained were as follows: For COD loading of $10kg/m^3$-day and five levels of ammonium nitrogen concentration ranging from 1,000 to 5,000 mg/L, organic removal efficiencies were about 81, 74, 67, 58, and 51%, and gas productions were 3,860, 3,520, 3,240, 3,020, and 2,790 ml/l-day, respectively. Average methane contents in the gas produced on COD loading of $10kg/m^3$-day was about 76%. Throughout the whole period of experiment, remaining VFA (as COD base) in the effluent was over 90% of remaining COD. This result indicated the inhibitory effect of high concentration of ammonium nitrogen through the facts that accumulated VFA was almost COD and organic removal efficiency decreased also with the increase of ammonium nitrogen. Especially, that implys which high concentration of ammonium nitrogen not only inhibits methane forming bacteria, but also acid forming bacteria.