Screening pretreatment methods for sludge disintegration to selectively reclaim carbon source from surplus activated sludge

Fermentative Hydrogen Production Using Disintegrated Waste-Activated Sludge by Low-Frequency Ultrasound Pretreatment

“…Besides the raw sludge, a similar phenomenon was also observed in tests with some treated sludge; Guo et al detected the protein increase in fermentative hydrogen production from sterilization and ultrasound-treated sludge. 51 However, for the test with sludge treated by alkaline, chlorine dioxide, homogenization, ozone, and ultrasound, no increase in soluble organic matter was observed, 13,51,52 indicating that the hydrolysis effect depends upon the sludge treatment process. The efficient treatment methods can make the hydrolysis effects during the fermentation process undetectable.…”

“…Waste-activated sludge is mainly composed of microbes, which can be a good organic source. Quite a few studies have explored energy as well as valuable chemical recovery from waste-activated sludge, such as biogas production, − alcohol generation, volatile fatty acid derivation, , and carbon source recovery for biological denitrification. , Considering the environmental benefits of hydrogen, waste-activated sludge is also used as the substrate for fermentative hydrogen production …”

“…Quite a few studies have explored energy as well as valuable chemical recovery from waste-activated sludge, such as biogas production, 4−9 alcohol generation, volatile fatty acid derivation, 10,11 and carbon source recovery for biological denitrification. 12,13 Considering the environmental benefits of hydrogen, waste-activated sludge is also used as the substrate for fermentative hydrogen production. 14 However, organic matter in waste-activated sludge is mostly encapsulated in microbial cells, which can hardly be used by hydrogen-producing microbes.…”

Pre-treatments to enhance the biodegradability of waste activated sludge: Elucidating the rate limiting step

“…As a result, the effects of pressure gradient, cavitation and shear are present (Zhang et al, 2012). During homogenization, pressure is the most significant factor for increasing the solubilization of COD (Li et al, 2014;Wahidunnabi and Eskicioglu, 2014;Zhang et al, 2012), while the number of homogenization cycles is less relevant (Zhang et al, 2012).…”

Dissolving organic matter from low-organic sewage sludge for shortening the anaerobic digestion time

“…pH of 10 under continuous stirring at 150 rpm, in which the optimized hydrolysis time is 1 h as reported in our previous studies. 18,19 Aer 1 h, the mixture was centrifuged at 4000 rpm for 10 min, and the rst-stage alkaline hydrolysis supernatant was discharged. The residual solid from reactor A was injected into reactor B, and X 2 mL of distilled water was injected.…”