摘要：Denitrification is a widely accepted method of water purification. The existing laboratory and field research results showed that denitrification bioreactor can effectively remove nitrate-nitrogen in farmland drainage. This study reports an experimental study on reduction processes of nitrogen through a pilot-scale denitrification bioreactor filled with rice husk. Three influent NO;-N concentrations; low(6～7 mg/L), medium(11～13 mg/L) and high(19～20 mg/L)were used under the same HRT(12 h), the reduction rate of NO3--N was highest when the NO3-N influent concentration was low which was 98%~99%. When the NO;-N concentration in influent was medium and high. the reduction rate was 93%~ 94%.The NO;- N reduction rate was correlated with hydraulic retention time (HRT). With medium influent concentration and the HRT of 6h, 9h and 12h,the reduction rates ofNO;-N were 63%~64%.78%~79% and93%~94%respectively. The reduction rate was also affected by temperature. When the HRT was 6h, the reduction rate of NO-N was 35%~37% at 5°C and above 40%when the temperature was above 15 ℃C. The experiment examined the different factors that affect the reduction and removal rates of nitrate-nitrogen. The calculations were based on observed field drainage discharge and the nitrogen concentrations, as well as the experimental results of bioreactor reduction rates. In the experiment, with medium loading rate of NO;-N(11-13 mg/L).for long hydraulic retention time of 12h, the observed reduction rate and denitrification rate of NO;-N in the rice-husk bioreactor was 93%and 0.93 mgL-'h-' respectively.
关键词：Bioreactor;Agricultural Drainage;Denitrification;Rice Husk;Carbon Media
