Effect of sodium dichloroisocyanurate treatment on enhancing the biodegradability of waste-activated sludge anaerobic fermentation

In the present study, a novel oxidant (sodium dichloroisocyanurate, NaCl2(NCO)3; SDIC) combined with microorganisms was employed to achieve a higher performance of waste-activated sludge (WAS) anaerobic fermentation. Four concentrations of SDIC (0, 0.3, 0.6, and 1.0 mg SDIC/mg SS) were studied in WAS fermentation systems. The results showed that the release of proteins and polysaccharides was enhanced by the addition of SDIC with values of 1002.25 mg COD/L and 680.25 mg COD/L, respectively, and these values increased 14.46?18.07 times (proteins) and 3.74?7.40 times (polysaccharides) compared with that of the blank test. Additionally, the short-chain fatty acids also increased 2.24 times. The rate of extraction of organic substances from the sludge increased from 3.03% to 33.33%. Furthermore, the fermented sludge with the SDIC treatment had higher hydrolytic acidification efficiencies for bovine serum albumin and glucose, increasing from 4.558% to 9.91% and 2.976%?6.764%, respectively. However, SDIC treatment of the conventional fermented sludge resulted in lower hydrolytic acidification efficiencies with values of 4.978%?1.781% and 3.334%?0.582%, respectively. Biological enzyme analysis also showed that SDIC enhanced ?-glucosidase and protease activity but inhibited dehydrogenase, alkaline phosphatase, and acid phosphatase activity. Proteobacteria and Comamonas were the main microbial communities observed in the WAS anaerobic fermentation.

Automated summary

The study demonstrated that the novel oxidant SDIC combined with microorganisms enhanced the performance of waste-activated sludge anaerobic fermentation. This combination resulted in increased release, extraction, and hydrolytic acidification efficiency of organic substances in the sludge. Additionally, SDIC treatment influenced the activity of various enzymes and affected the microbial communities in the sludge fermentation process.