Improved Bioconversion of Volatile Fatty Acids from Waste Activated Sludge by Pretreatment
Abstract:Batch tests were conducted to analyze the influence of various pretreatment methods including thermo-alkaline, thermo-acid, ultrasonic-alkaline, and ultrasonic-acid on the bioconversion of volatile fatty acids (VFAs) from waste activated sludge. Experimental results showed that total VFAs (TVFAs) increased by 68.2% for ultrasonic-alkaline and 59.1% for thermo-alkaline. The TVFAs bioconversion in the case of the thermo-acid or ultrasonic-acid pretreatment, however, was lower than that without pretreatment. The results of VFA distribution showed that acetic acid was the most prevalent product, with a fraction of 35.5 to 57.2% for all cases. The mechanism of VFA production was then investigated. Results revealed that, in the two alkaline-pretreated slurries, soluble COD and soluble BOD/soluble COD significantly increased to yield more soluble substrate for the subsequent fermentation. Soluble proteins comprised the main substance provided that was converted to VFAs. A further investigation indicated that volatile (organic) solids, including insoluble proteins, in the solid phase of the samples pretreated with these two methods were hardly consumed during the fermentation.
Document Type: Research Article
Publication date: January 1, 2009
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- Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.
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