LAUSR

In this article, a promising pretreatment method (ferrate pretreatment with alkaline conditions) is reported to enhance the anaerobic fermentation performance of WAS. Experimental results revealed that the maximal VFA production of 322.6 mg COD/g VSS (volatile suspended solids) was achieved at day 5 in the combined test (ferrate of 0.5 g/g VSS with pH10) while that of the blank test was 135.1 mg COD/g VSS at day 6. Acetic acid was significantly enriched in the combined test (57%) compared with the blank (35.9%). A mechanism study showed that the ferrate with an alkaline condition accelerated all the solubilization, hydrolysis, and acidification processes, which could be concluded from the improved performance and enhanced activities of key enzymes involved. The microbial community analysis elucidated that the abundance of phyla Firmicutes and Bacteroidetes increased after the combined pretreatment, which might account for the improvement of hydrolysis and acidification. It was further supported by the fac...