不同电解质对电化学预处理剩余污泥厌氧发酵产挥发性脂肪酸的影响

电化学预处理剩余污泥(waste activated sludge, WAS)厌氧发酵(anaerobic fermentation, AF)产挥发性脂肪酸(volatile fatty acids, VFAs)具有良好的应用价值和环境效益,然而不同电解质对电化学预处理剩余污泥以及厌氧发酵的效果具有较大影响。因此,实验考查了不同电解质(空白对照,NaCl,Na₂SO₄和CaCl₂)在电流强度为1 A、预处理时间为60 min的电化学处理条件下,对剩余污泥厌氧发酵产VFAs的影响。结果表明:当0.05 mol/L NaCl作为电解质时,在电化学预处理阶段污泥有机质(溶解性COD、多糖、蛋白质等)溶出效果较其他电解质更好。在厌氧发酵阶段,该条件下VFAs最大累积量可达到2625.8 mg COD/L,相比空白对照组提升了51.6%,表明NaCl作为电解质的电化学预处理不仅能够有效促进剩余污泥中有机质溶出,而且有利于产酸微生物(如Firmicutes和Bacteroidetes)的富集,从而促进厌氧发酵产VFAs,达到提高污泥资源化利用率的目的。

EFFECTS OF ELECTROLYTES ON ACIDOGENIC FERMENTATION OF WASTE ACTIVATED SLUDGE FOR VOLATILE FATTY ACIDS PRODUCTION VIA ELECTROCHEMICAL PRETREATMENT

Anaerobic fermentation (AF) of waste activated sludge (WAS) via electrochemical pretreatment (EPT) is a practical, effective and cost-saving protocol for volatile fatty acids (VFAs) production. However, AF performance is significantly affected by the different electrolytes during EPT. This study aimed to investigate the effects of different types of electrolytes (Control, NaCl, Na₂SO₄ and CaCl₂) on VFAs production from AF of WAS via EPT with a current intensity at 1 A for 60 min. The results showed that by using 0.05 mol/L NaCl as the electrolyte during EPT, the amount of organic matter released from WAS, such as soluble COD, glycogen, protein etc., was the highest compared to other electrolytes. Thus the maximal VFAs accumulation during AF via EPT by using NaCl as the electrolyte reached 2625.8 mg COD/L, which was 51.6% higher than that of the control. These results indicated that EPT with NaCl as the electrolyte could effectively improve the hydrolysis of WAS, increase the amount of organic matter released from WAS and promote the enrichment of anaerobic fermentative bacteria (such as Firmicutes and Bacteroidetes). All of these subsequently promoted the AF of WAS and thus increased VFAs production, which in turn enhanced the resource recovery from WAS treatment.