摘要：Denitrification bioreactors have been proved successful in removing nitrate loads from agricul-tural drainage water. One of the key factors affecting bioreactor performance is the organic carbon sub-strate used in the bioreactor. The quest to find an ap-propriate carbon substrate that not only enhance ni-trate-nitrogen(NO3.-N)reduction to gaseous ni-trogen (M2),but also increase longevity of the deni-trification bioreactor becomes an important issue.In this study, five denitrification bioreactors having dif-ferent combinations of rice-husk and woodchips were assessed using low(1 mg/L), medium(5 mg/L), and high(15 mg/L) influent concentrations. The re-sults showed that a combination of both C-substrate led to a quick start and high removal rate of nitrate nitrogen, at hydraulic retention time of 8hr, the re-moval rate was 0.98 gm-3day-1,6.98 gm-3day-1 and 13.98 gm-3day-1 for influent concentration of 1.5 and 15 mg/L,respectively.Bet-ter performance of the bioreactors (91%removalef-ficiency)was observed at higher influent concentra-tion, indicating that nitrogen removal with bioreac-tors was highly dependent on influent concentration. The experimental results showed that a mixture of the readily and slowly available carbon substrate can be effectively used to remove nitrate nitrogen from agricultural drainage water.
