含砂量对污泥碱性发酵产挥发性脂肪酸的影响

Effect of Grit Content on Volatile Fatty Acids Production in Sludge Alkaline Fermentation

我国城市污水处理厂普遍存在污泥含砂量较高的现象。研究了含砂量(15%、30%、45%和60%)对污泥碱性发酵产挥发性脂肪酸(VFAs)的影响。结果表明,含砂量的升高抑制了污泥的水解酸化,含砂量从15%升高至60%,VFAs从(314.0±11.93)mg CODCr/(g VSS)降至(257.1±12.34)mg CODCr/(g VSS)。随含砂量的升高,溶解性蛋白质浓度从(75.83±2.79)mg/(g VSS)下降至(58.40±0.90)mg/(g VSS),类色氨酸和类芳香蛋白质的荧光强度以及小相对分子质量(<1 kDa)蛋白质的浓度均有所下降,Firmicutes(厚壁菌门)、Proteobacteria(变形菌门)及Acinetobacter(不动杆菌属)等水解酸化细菌的丰度也明显降低,进而导致了VFAs产量的降低。本研究对于高含砂量污泥碱性发酵产酸系统的运行优化具有指导意义。

High grit content has been widely found in sludge of wastewater treatment plants in China.This paper investigated the effects of grit content(15%,30%,45%and 60%)on volatile fatty acids(VFAs)production during sludge alkaline fermentation.Results showed that the increase of grit content inhibited the sludge hydrolysis and acidification.VFAs concentration decreased from(314.0±11.93)mg CODCr/(g VSS)to(257.1±12.34)mg CODCr/(g VSS)as the grit content increased from 15%to 60%.With the increase of grit content,the concentration of soluble protein decreased from(75.83±2.79)mg/(g VSS)to(58.40±0.90)mg/(g VSS).The fluorescence intensity of tryptophan-like and aromatic protein-like substances,and the concentration of low molecular weight(<1 kDa)soluble protein decreased with the increase of grit content.Meanwhile,the abundance of hydrolytic acidification bacteria such as Firmicutes,Proteobacteria and Acinetobacter also decreased with the increase of grit content.These findings resulted in the decrease of VFAs production.This study provides guiding significance for the optimized operation of alkaline fermentation system for VFAs production of sludge with high grit content.