低浓度乙酸盐诱导下厌氧氨氧化与异养反硝化高效耦合脱氮

Nitrogen removal performance of anammox coupling heterotrophic denitrification in low concentration of acetate

通过连续流实验研究了低浓度乙酸盐诱导下厌氧氨氧化颗粒污泥与异养反硝化菌的耦合脱氮性能,同时采用批试实验考察耦合系统中的氮素转化及去除途径。结果表明:采用低浓度乙酸盐对厌氧氨氧化颗粒污泥进行驯化,可以实现厌氧氨氧化与异养反硝化的高效耦合脱氮。系统在稳定时期,进水NH_4^+-N为30~40 mg·L^(-1)、NO_2^--N为45~55 mg·L^(-1)、CH_3COONa为60~80 mg·L^(-1),NH_4^+-N、NO_2^--N和TN的去除率分别为93.84%、94.62%和86.46%。耦合系统中的颗粒污泥同时存在厌氧氨氧化特性、硝化特性和反硝化特性。颗粒污泥表现出良好的厌氧氨氧化特性,总氮去除速率为12.46 mg·(g MLSS·h)^(-1)。系统中存在的硝化细菌可以消耗进水中的溶解氧从而缓解溶解氧对ANAMMOX菌的抑制,其中AOB活性高于NOB活性。系统中颗粒污泥对硝氮的反硝化作用强于对亚硝氮的反硝化作用,亚硝氮反硝化和硝氮反硝化的降解速率分别为1.89和3.59 mg·(g MLSS·h)^(-1)。当亚硝氮和硝氮同时存在时,反硝化菌优先将硝氮还原成亚硝氮。

We investigated the nitrogen removal performance of anaerobic ammonium-oxidizing（ anammox）granules in a reactor under continuous cultivation at low acetate concentration. As a comparison,we applied batch tests to measure the nitrogen transformation and removal pathways of granules obtained from the coupling reactor.The reactor exhibited excellent anammox and denitrifying performances at low acetate concentration. During steady phase,removal rates of NH_4~＋-N,NO_2^--N,and TN were 93. 84%,94. 62%,and 86. 46%,respectively. Batch tests indicated that the coupling anammox granules exhibited good anammox,nitrification,and denitrification activities. The total nitrogen removal rate of coupling granules was 12. 46 mg·（ g MLSS·h）^（-1）. Nitrifying bacteria in the system were capable of consuming the dissolved oxygen,thus lessening the inhibitory effect of oxygen on anammox bacteria. As a result,activity of ammonia-oxidizing bacteria（ AOB） was higher than that of nitrite-oxidizing bacteria（ NOB）. Denitrification rates for nitrite and nitrate were 1. 89 and 3. 59 mg·（ g MLSS·h）^（-1）,respectively.When nitrite and nitrate were present simultaneously,denitrifying bacteria reduced nitrate to nitrite first.