游离氨对活性污泥系统中脱氮性能及胞外聚合物的影响

Effect of free ammonia on nitrogen removal and extracellular polymeric substances in the suspended activated sludge system

以人工模拟废水为研究对象,采用4组SBR反应器(R0.5、R5、R10和R15),考察了4种游离氨浓度(0.5、5、10和15mg/L)对生物脱氮效能、胞外聚合物含量及其组分(蛋白质(PN)、多糖(PS)和核酸(DNA))影响。结果表明,4种游离氨浓度条件下都实现了较高的脱氮效果(97.6%~99.4%)。游离氨对3种胞外聚合物(LB-EPS、TB-EPS、总EPS)及其组分有显著影响。当游离氨浓度从0.5mg/L增加到10mg/L时,LB-EPS、TB-EPS、总EPS的含量及其组分的含量都显著增加;当游离氨浓度进一步增加到15mg/L时,LB-EPS、TB-EPS、总EPS的含量及其组分的含量都呈降低的趋势;在4个游离氨浓度下,PN是LB-EPS的主要成分,PS是TB-EPS和总EPS的主要成分;在4个游离氨浓度下的整个反应周期中,3种胞外聚合物及其组分的含量都跟NOx-—N有着相同的变化趋势。

To investigate the influences of free ammonia on nitrogen removal,the contents of extracellular polymeric substances and the chemical composition(proteins,polysaccharides,and DNA),four laboratory-scale sequencing batch reactors fed with synthetic wastewater were operated at free ammonia concentrations of 0.5,5,10and 15mg/L(R0.5,R5,R10and R15,respectively).Results showed that high nitrogen removal efficiencies(97.6%~99.4%)were achieved under four free ammonia concentrations.Free ammonia had a significant impact on the three kinds of extracellular polymeric substance(loosely bound extracellular polymeric substance,tightly bound extracellular polymeric substance and total extracellular polymeric substance,respectively)and their composition.Results showed that with the increased of initial free ammonia concentrations from 0.5to 10 mg/L,the production of three kinds of extracellular polymeric substance and their components were significantly increased.Further increased of free ammonia concentrations to 15mg/L caused a decreased trend of them.Moreover,proteins were the main component of loosely bound extracellular polymeric substance,while polysaccharides dominated in tightly bound extracellular polymeric substance and total extracellular polymeric substance under different free ammonia concentrations.It was found that the contents of three kinds of extracellular polymeric substance and their components showed a similar variation tendency to the NOx-—N contents during the whole cycle under four free ammonia concentrations.