夜間水抜き操作を導入したゼオライト水耕排水処理施設の窒素除去に関する研究

概要

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A subsurface flow-constructed wetland with a zeolite substratum (S.F.Z.) is characterized by a high removal rate of ammonium nitrogen due to its high ion-exchange capacity. However, after the saturation of ammonium ions (NH4+) in the zeolite, the rate is markedly decreased. We investigated the effect of nighttime drainage operation for the recovery of the NH4+ ion-exchange capacity of zeolite using a large-scale experimental S.F.Z plant. The experiment was carried out using two channels which had different influent water loads and frequencies of drainage operation. Channel 1 was drained every night and Channel 2 was drained three times per week in the nighttime (0:00∼6:00). The results showed that the amount of adsorbed NH4+ in the zeolite was decreased by nitrification after the operation. NO3--N concentration was increased in the effluent of Channel 1, however, it was not increased in Channel 2. The increase in NO3--N by nitrification could be reduced by controlling the frequency of the drainage operation and the influent water load. High removal rates of NH4+ and inorganic nitrogen were observed for 9 months after the start of drainage operation. Therefore, the S.F.Z. can be used long-term with a high performance in nitrogen removal through the introduction of a suitable drain operation.
社団法人　日本水環境学会の論文
2006-06-10