混合外源菌强化剩余污泥微氧水解产酸

Effect of mixed yeast of acetic bacteria on acid production from micro-aerobic hydrolysis of excess sludge

利用外源投加酵母菌与醋酸菌的方式促进了剩余污泥水解产生短链挥发性脂肪酸(SCFAs)的产量,考察了混合投加模式下污泥水解溶出的正磷酸盐、氨氮和溶解性COD的浓度,研究水解过程胞外聚合物(EPS)组分中蛋白质及多糖的变化特征.结果表明,在酵母菌和醋酸菌投加量分别为10和20g/L时,发酵第5d实现了最高的SCFAs产量,达到719mgCOD/gVSS,其中乙酸含量为328.78mgCOD/gVSS,占总SCFAs的45.72%.投加两种菌显著促进了剩余污泥水解产生SCFAs,且以乙酸为主.外源菌投加促进了水解酸化过程氨氮和正磷酸盐的释放,最佳反应条件下最大释放量分别为80.66和22.38mg/gVSS,有利于从剩余污泥中回收氮磷.投加外源菌后EPS中的蛋白质和多糖从内层向最外层释放,为污泥水解产酸提供底物.外源投加酵母菌与醋酸菌是促进剩余污泥水解酸化的有效手段.

This study focused on the optimal concentration of yeast mixed with acetic bacteria to promote sludge hydrolysis and acidification.The concentrations of orthophosphate,ammonia nitrogen and soluble COD released from sludge were investigated.The changes of protein and polysaccharide in extracellular polymeric substances(EPS)at different layers were also studied.At yeast and acetic acid bacteria dosage of 10 and 20g/L,the highest short chain fatty acids(SCFAs)production of 719mgCOD/gVSS was achieved on the fifth day of fermentation,in which the acetic acid was 328.78mgCOD/gVSS,accounting for 45.72%of the total SCFAs.Adding exogenous bacteria significantly promoted the hydrolysis of excess sludge to produce SCFAs with acetic acid as the main component.The addition of exogenous bacteria promoted the release of ammonia nitrogen and orthophosphate during hydrolysis acidification.The maximum release of ammonia nitrogen and orthophosphate was 80.66mg/gVSS and 22.38mg/gVSS under the optimal conditions,respectively,which was conducive to the recovery of nitrogen and phosphorus from excess sludge.The release of proteins and polysaccharides from the inner layer to the outer layer of EPS was improved,providing substrates for acid production.Exogenous addition of yeast and acetic acid bacteria was an effective means to promote hydrolysis and acidification of excess sludge.