[Enhanced hydrolysis and acidification of waste activated sludge by alkyl polyglycosides].

ABSTRACT

The effects of biosurfactant alkyl polyglycosides (APG) on the hydrolysis and acidification of waste activited sludge including dosage of APG and hydrolysis time were investigated. It was found that APG reduced the tension of sludge hydrolysate, promoting sludge hydrolysis. The concentrations of SCOD, protein and soluble carbonhydrate reached the maximum within 12 h at the optimal dosage of 0.2 g x g(-1) TSS, rising from 4 280.2, 1 122.9 and 246.5 mg x L(-1) to 6481.1, 1 639.3 and 1205.8 mg x L(-1), respectively, and the short-chain fatty acids (SCFAs) concentration increased from 1309.9 mg x L(-1) to 2221.6 mg x L(-1) simultaneously, the percentage of individual SCFA changed as well, and the time required to reach the maximal SCFAs concentration will be prolonged with the increase of dosage. With increasing APG dosage, a-glucosidase relative enzyme activities increased from 1.5 to 2.5, while protease relative enzyme activity increased from 1.4 to 1.9 at low dosages and decreased to 1.5 at high dosages. Regardless of the biosurfactant APG, alpha-glucosidase and protease enzyme activities decreased along with the hydrolysis time. The pH showed a tendency of first decreasing and then increasing.