一体式部分亚硝化-厌氧氨氧化工艺污泥膨胀发生和恢复过程中胞外聚合物变化特征

Study on the characteristics of extracellular polymeric substances changes during the sludge bulking occurrence and restoration in one-stage combined partial nitritation and Anammox process

胞外聚合物(Extracellular Polymeric Substances,EPS)对污泥沉降具有重要作用.以一体式部分亚硝化-厌氧氨氧化工艺为对象,针对出现的污泥膨胀问题,通过停止投加乙酸钠、调整SRT和曝停比等措施控制了污泥膨胀,并考察整个过程中胞外聚合物变化特征.结果表明,阶段Ⅰ~Ⅱ(0~77 d),SVI升至215.86 mL·g^(-1),TN去除率仍稳定在60.88%;阶段Ⅲ(78~109 d),SVI维持在210.16 mL·g^(-1),TN去除率下降至32.19%;阶段Ⅳ(110~140 d),SVI下降至107.53 mL·g^(-1),TN去除率也恢复至54.55%,AOB、NOB和ANAMMOX活性分别恢复至0.42、0.06、0.20 g·g^(-1)·d^(-1).污泥膨胀得到控制以后,溶解性EPS(Solubility EPS,S-EPS)、溶解性蛋白(Solubility PN,S-PN)从243.15、213.25 mg·g^(-1)分别下降至110.97、49.52 mg·g^(-1).三维荧光光谱分析表明,投加乙酸钠PN含量呈上升趋势,PS含量下降.PⅠCRUSt2对蛋白质(PN)、多糖(PS)代谢分析也表明,停止投加乙酸钠以后,氨基酸代谢基因丰度降低,疏水性增强,PS更多地转为内源性有机物供微生物利用.

Extracellular polymeric substances(EPS)play an important role in sludge settlement.This research was based on the one-stage combined partial nitritation and anammox process.Given the sludge bulking problem,the sludge bulking was controlled by stopping dosing sodium acetate,adjusting SRT and aeration stop ratio,and the change characteristics of extracellular polymers in the whole process were investigated.The results showed that in stage Ⅰ-Ⅱ(0~77 d),although SVI rose to 215.86 mL·g^(-1),the TN removal rate remained stable at 60.88%;in stage Ⅲ(78~109 d),SVI remained at 210.16 mL·g^(-1),TN removal rate dropped to 32.19%,stage Ⅳ(110~140 d),SVI dropped to 107.53 mL·g^(-1),TN removal rate also recovered to 54.55%,AOB,NOB and ANAMMOX activities correspondingly recovered to 0.42,0.06,0.20 g·g^(-1)·d^(-1).After sludge bulking was controlled,the main components that affect the solubility of EPS(Solubility EPS,S-EPS)and solubility protein(Solubility PN,S-PN)decreased from243.15,213.25 mg·g^(-1)to 110.97,49.52 mg·g^(-1).Three-dimensional fluorescence spectroscopy analysis shows that the PN content increased and the PS content decreased while adding sodium acetate.PICRUSt2’s analysis of PN and PS metabolism also shows that after the sodium acetate was stopped,the abundance of amino acid metabolism genes decreased,the hydrophobicity increased and more PS was converted into endogenous organic matter for microbial utilization.