ABSTRACT

Persulphates, an advanced oxidation process, has been recently used as an alternative pretreatment method to enhance short-chain fatty acids (SCFAs) yield from waste-activated sludge (WAS) anaerobic fermentation (AF). But so far, the effects of peroxydisulphate (PDS) dosages on mesophilic anaerobic fermentation are still not studied fully. Herein, we explored the influences of potassium PDS addition on mesophilic AF of WAS. Notably, the addition of PDS could drastically accelerate WAS solubilization and hydrolysis, which was proportional to the amount of PDS. The maximal total SCFAs yield of 249.14 mg chemical oxygen demand/L was obtained with 120 mg PDS/g suspended solids addition at 6 days of AF, which was 2.2-fold that of the control one. Tightly bound extracellular polymeric substances (EPSs) were transformed into loosely bound EPS and dissolved organic matters, and aromatic proteins and humic-like substances of EPSs were disintegrated, which were caused by the devastating effects of PDS treatments on EPSs disruption. The intracellular constituents of microbial cells in the sludge were released accordingly. As a result, there was release of soluble substrates derived from the disintegration of both EPSs and cells, the amounts of which were proportional to the dose of PDS. Moreover, microbial diversity and richness were both decreased in the presence of PDS, and the relative abundance of phyla Actinobacteria increased with the increase of the PDS dosage. In addition, the stability of sludge flocs was destroyed in the presence of PDS, the distribution of particle size tended to be small and dispersive, and dewaterability of the sludge was deteriorated.

摘要

过硫酸盐是一种高级氧化工艺，最近已被用作一种替代预处理方法，以提高废物活性污泥 (WAS) 厌氧发酵 (AF) 的短链脂肪酸 (SCFA) 产量。但到目前为止，过氧化二硫酸盐（PDS）剂量对中温厌氧发酵的影响仍未得到充分研究。在此，我们探讨了钾 PDS 添加对 WAS 中温 AF 的影响。值得注意的是，添加 PDS 可以显着加速 WAS 的溶解和水解，这与 PDS 的量成正比。在 AF 6 天添加 120 mg PDS/g 悬浮固体时，获得的最大总 SCFA 产量为 249.14 mg 化学需氧量/L，是对照的 2.2 倍。紧密结合的胞外聚合物（EPS）转化为松散结合的EPS和溶解的有机物，EPS的芳香蛋白和腐殖质样物质分解，这是由于PDS处理对EPS破坏的破坏性影响所致。污泥中微生物细胞的胞内成分相应释放。结果，EPS 和细胞分解产生的可溶性底物释放，其量与 PDS 的剂量成正比。此外，PDS存在下微生物多样性和丰富度均降低，放线菌门的相对丰度随着PDS剂量的增加而增加。此外，PDS 的存在破坏了污泥絮体的稳定性，