Abstract:

In order to realize efficient synchronous nitrogen and phosphorus removal from the domestic wastewater, a zero-valent iron coupled anaerobic ammonium oxidation (anammox) system was constructed, and the short-term effects of zero-valent iron on the nitrogen and phosphorus removal efficacy of anammox, the characteristics of granular sludge, and the key enzyme activities were investigated, and the mechanism of the system's efficient synchronous nitrogen and phosphorus removal was analyzed. The results showed that when the dosage of zero-valent iron was 1.0g, the temperature was 35℃, and the reaction time was 12h, the concentrations of ammonia nitrogen, total nitrogen and total phosphorus were 0.82mg/L, 5.36mg/L and 0.66mg/L, respectively, and the removal efficiencies of total nitrogen and total phosphorus were higher than those of the control group by 14.8% and 70.3%, respectively. At this time, the surface of granular sludge was covered with a small amount of zero-valent iron and its oxides and precipitates. The color became darker, the texture became harder, the structural strength increased, and the proportion of iron reached 35.4%.The decrease of loosely bound EPS and the increase of tightly bound EPS in the granular sludge were favorable to improve the settling performance of the granular sludge and resist the influence of external unfavorable factors. The increase of oxygen-containing functional groups, such as hydroxyl and carbonyl groups, on the surface of granular sludge promoted the metabolic activities in the anammox system. The activities of nitrate reductase, nitrite reductase and hydrazine synthase were increased in the anammox system, which improved the nitrogen removal efficiency of the system. This study can provide a theoretical basis for the efficient and low-carbon simultaneous removal of nitrogen and phosphorus from domestic wastewater.

Key words: zero-valent iron, anammox, domestic sewage, nitrogen removal, phosphorus removal

摘要：

为实现生活污水高效同步脱氮除磷，构建了零价铁耦合厌氧氨氧化系统，探究了零价铁对厌氧氨氧化短期脱氮除磷效能、颗粒污泥特性和关键酶活性的影响，并分析了系统高效同步脱氮除磷机理。结果表明，当零价铁投加量为1g，温度为35℃，反应12h后，氨氮、总氮和总磷浓度分别为0.82mg/L、5.36mg/L和0.66mg/L，总氮和总磷去除率分别比对照组高出14.8%和70.3%。此时颗粒污泥表面覆盖了少量的零价铁及其氧化物和沉淀物，颜色变黑，质地变硬，结构强度增大，铁元素占比达到35.4%。颗粒污泥中松散结合型EPS减少，紧密结合型EPS增加，有利于提高颗粒污泥的沉降性能和抵御外界不利因素的影响。颗粒污泥表面的羟基和羰基等含氧官能团增加，促进了厌氧氨氧化系统中的新陈代谢活动。厌氧氨氧化系统中硝酸还原酶、亚硝酸还原酶和联氨合成酶活性增加，从而提高了系统的脱氮效能。该研究可为生活污水中氮磷的高效低碳同步去除提供理论基础。

关键词: 零价铁, 厌氧氨氧化, 生活污水, 脱氮, 除磷