Liu X L, Liu H, Du G C, Chen J
Laboratory of Environmental Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, China.
Water Environ Res. 2009 Jan;81(1):13-20. doi: 10.2175/106143008x304640.
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.
进行了批次试验，以分析包括热碱、热酸、超声碱和超声酸在内的各种预处理方法对废弃活性污泥中挥发性脂肪酸（VFA）生物转化的影响。实验结果表明，超声碱预处理使总挥发性脂肪酸（TVFA）增加了68.2%，热碱预处理使TVFA增加了59.1%。然而，热酸或超声酸预处理情况下的TVFA生物转化率低于未预处理的情况。VFA分布结果表明，乙酸是最主要的产物，在所有情况下其占比为35.5%至57.2%。随后研究了VFA的产生机制。结果显示，在两种碱预处理的污泥中，可溶性化学需氧量（COD）和可溶性生化需氧量/可溶性COD显著增加，从而为后续发酵产生更多的可溶性底物。可溶性蛋白质是转化为VFA的主要物质。进一步研究表明，用这两种方法预处理的样品固相中的挥发性（有机）固体，包括不溶性蛋白质，在发酵过程中几乎未被消耗。
