内源电子受体对剩余污泥释磷行为的影响

Effect of in-stream electron acceptor on phosphorous release behaviour of excess activated sludge

采用生物脱氮除磷工艺中剩余活性污泥所含硝化细菌处理生产废水的新型硝化工艺,将生产废水中所含氨氮转化为硝酸盐,获得一种从污水处理工艺中产生的内源电子受体。研究内源电子受体的产生特征及其用于抑制富磷剩余污泥在重力浓缩过程中磷的释放特征。结果表明:(1)采用剩余污泥处理生产废水工艺用于产生内源电子受体时,最佳曝气时间为24 h,可将液相中氨氮由41.20 mg/L降为0.19 mg/L;同时,硝酸盐由1.14 mg/L升高至32.62 mg/L,可作为一种潜在的内源电子受体用于抑制重力浓缩过程中剩余活性污泥释磷;(2)当内源电子受体硝酸盐浓度为36.16 mg/L时,经后续的重力浓缩(24 h)后,回流液中磷浓度为44.87 mg/L,与浓缩池上清液直接回流(100%回流并积累)相比,磷积累量降低了65.44%;同时,硝酸盐氮在这一过程中发生反硝化,由36.16 mg/L降至4.84 mg/L。同时,与生产废水直接回流(100%回流并积累)相比,该新型工艺引起氨氮积累量仅为17.68%。上述结果表明:采用内源电子受体,不仅可以有效降低生物脱氮除磷工艺中生产废水回流而引起的磷积累量,而且可同步减少氨氮的循环积累量。

In this study, a novel in-stream electron acceptor, which generated from the reject water treat- ment process using excess activated sludge of the biological nitrogen （N） and phosphorous （P） removal process as nitrobacter, was used to control P-release from the P-enriched excess activated sludge （EAS） during gravity thickening process. The objectives of this study were （ 1 ） to determine the optimal nitrification time for in-stream electron acceptor （ i. e. nitrate） generation from the reject water treatment system using EAS as nitrifying bacteria and （2） to investigate the P-release characteristics of EAS during the gravity thickening process using in-stream electron acceptor as inhibitor. Experimental results showed that the optimal nitrification time for in-stream elec- tron acceptor （i. e. nitrate） generation is 24 h which can lead to the ammoniumcal-N in the reject water de- creased from 41.20 mg/L to 0. 19 mg/L while the nitrate increased from 1.14 mg/L to 32.62 mg/L. This indi- cates that the nitrate, an in-stream electron, was generated and can potentially be used as inhibitor to reduce the amount P-release from EAS during the gravity thickening process. The results showed that the phosphorus in the reject water was changed to 44. 87 mg/L when the in-stream electron was 36. 16 mg/L. This results in 65.44% of P-feedback through reject water recycling decreased. Meanwhile, the in-stream nitrate decreased from 36.16 mg/L to 4.84 mg/L. The amount of ammoniumcal-N feedback through reject water recycling decreased from 100% to 17.68%. This indicates that significant amount of P and N feedback in the biological N and P removal process can be reduced using the in-stream electron acceptor.