オリゴトロフィー性好気性脱窒剤の窒素除去性能と窒素/炭素バランス

[Nitrogen Removal Performance and Nitrogen/Carbon Balance of Oligotrophic Aerobic Denitrifiers].

• Gang Wen
• Tong Wang
• Ting-Lin Huang
• Qi-Qi Wan
• Rui-Hua Cao
• Li-Qing Kou
• Shang-Ye Yang

抄録

寡栄養貯水池の生物学的脱窒処理における窒素除去効率の低さと電子移動の不明確さが問題となっていたため、効率的な窒素除去能力を有する好気性脱窒剤ZMF5を用いて、窒素除去特性、環境適応性、脱窒時の電子移動について系統的に検討した。その結果、①菌株ZMF5は効率的な従属栄養性硝化能力と好気性脱窒能力を示し、アンモニア除去率は0.211mg-(L-h)、硝酸塩除去率は0.236mg-(L-h)であり、処理過程で硝化中間体が蓄積されないことがわかった。ZMF5株の窒素除去効率と生育速度を解析したところ、ZMF5株は低C/N、低pH、低温条件下でも異なる種類の炭素源を有効に利用でき、効率的な窒素除去効率を示すことが明らかになった。炭素収支の解析から、脱窒過程ではほとんどの炭素源が電子供与体として利用されるが、硝酸塩還元に利用される電子は少なく、炭素源の違いによって硝酸塩呼吸鎖への電子移動は還元電位、電子供与体の豊富さ、分子量の違いによって制御されていることがわかった。 ZMF5は、飲料水貯水池の窒素汚染を抑制するために利用できる可能性がある。

Due to the problems of low nitrogen removal efficiency and unclear electron transfer during biological denitrification treatment of an oligotrophic drinking water reservoir, the nitrogen removal characteristics, environmental adaptability, and electron transfer during denitrification were systematically studied using the aerobic denitrifier ZMF5, which has efficient nitrogen removal ability. The results showed that:① Strain ZMF5 exhibited efficient heterotrophic nitrification and aerobic denitrification ability, with an ammonia removal rate of 0.211 mg·(L·h) and a nitrate removal rate of 0.236 mg·(L·h), and the nitrification intermediates were not accumulated during the treatment process. ② According to analysis of the nitrogen removal efficiency and growth kinetics of strain ZMF5, the strain can effectively utilize different types of carbon source, and show efficient nitrogen removal efficiency under the conditions of low C/N, low pH, and low temperature. ③ Analysis of nitrogen balance showed that carboxylate compound, compared with carbohydrate, could promote the process of aerobic denitrification and change the nitrogen removal pathway of strain ZMF5, i.e., 38.81% of nitrogen was transformed into gas, higher than the 29.81% for assimilation. ④ Analysis of carbon balance indicated that most carbon sources were used as electron donors in the denitrification process, but fewer electrons were used for nitrate reduction, and with respect to different carbon sources, electron transfer to the nitrate respiratory chain was regulated by different reduction potentials, electron donor abundance, and molecular weight. ZMF5 could be used to control nitrogen pollution in drinking water reservoirs.