SRT对于污水脱氮过程中N2O产生的影响

试验采用经过长期驯化,控制污泥龄分别为9d和15d的活性污泥,以实际生活污水为研究对象,考察了不同污泥龄(SRT)对污水脱氮过程中N2O的产生量和转化率的影响.结果表明N2O主要产生于污水脱氮的硝化过程中,而反硝化过程的贡献较少.较短的污泥龄有利于脱氮过程中N2O的产生,9d污泥龄的活性污泥系统产生N2O量是15d污泥龄污泥系统的1.2倍,分别为4.62mg·L-1和3.8mg·L-1.不同污泥龄条件下产生N2O的转化率也有所差别,污泥龄较短的活性污泥系统产生N2O的转化率也较高,分别为11.2%和7.8%.系统经长期在较短的污泥龄下运行,并没有影响系统的脱氮效果,两种污泥龄条件下系统的脱氮率都在96%以上.为了减少污水脱氮过程中N20的产生量,应避免污水处理系统过短的污泥龄,造成污水脱氮过程N2O的产量和转化率的大幅升高.

Effects of SRT on N2O production during nitrification and denitrification

We investigated the production and conversion rate of N2O during nitrification and denitrification under different sludge retention times (SRT): 9 d and 15 d. The results showed that nitrification was the main source of N2O. The N2O production with SRT 9 d was 1.2 times higher than that with SRT 15 d.The production and conversion rate of N2O during nitrification and denitrification under different SRT conditions were also investigated. The results turned out that the N2O production was 4.62 mg·L-1 with SRT 9 d and 3.8 mg·L-1 with SRT 15d. The conversion rate was 11.2% with SRT 9d and 7.8% with SRT 15d. The long time domesticated short SRT system can perform a good nitrogen removal rate, under the two SRT conditions, the nitrogen removal rates were all above 96%. Consequently, in order to reduce N2O production, it is necessary to keep a long SRT to avoid increasing the N2O production and conversion rate.