Improved bioproduction of short-chain fatty acids (SCFAs) from excess sludge under alkaline conditions
Improved bioproduction of short-chain fatty acids (SCFAs) from excess sludge under alkaline conditions
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DOI：
10.1021/es052252b
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发表时间：
2006-03-15
影响因子：
11.4
通讯作者：
Gu, GW
中科院分区：
文献类型：
--
作者：
Yuan, HY;Chen, YG;Gu, GW
在4.0至11.0的不同pH值下进行间歇发酵试验，利用剩余污泥生产短链脂肪酸(SCFA)。不同pH值对SCFAs产量影响的实验结果表明，在第一个8天的发酵时间内，pH 9.0或pH 10.0下的SCFAs总产量远高于酸性或中性pH值，并且在pH 10.0时每克挥发性悬浮固体（VSS）的最大产量为256.2 mg SCFAs-COD，分别是pH 5.0时的3倍和4倍以上和 不受控制的 pH 值。显然，通过将发酵pH控制在10.0，可以显着提高剩余污泥中SCFA的产量并保持稳定。分析了 pH 10.0 下 SCFA 的组成以及单个 SCFA 占总 SCFA 的百分比分布。 SCFA 由乙酸、丙酸、异丁酸、正丁酸、异戊酸和正戊酸组成，乙酸是最常见的产品，比例为 40-55%。由于本研究的结果与以往 SCFAs 产量研究的结果不同，因此研究了碱性条件下 SCFAs 产量增加的机制。结果表明，随着可溶性 COD 的增加，可提供更多的可溶性蛋白质作为生产 SCFA 的底物。此外，在碱性pH条件下，产甲烷菌消耗的SCFAs较少甚至没有，因此SCFAs的产量因此显着提高。进一步的研究表明，pH 10.0 时 SCFA 的形成主要是生物效应，而不是化学水解。
The production of short-chain fatty acids (SCFAs) from excess sludge was conducted in batch fermentation tests at different pH values ranging from 4.0 to 11.0. Experimental results of the impacts of different pHs on SCFAs production showed that during the first 8-day fermentation time the total SCFAs production at either pH 9.0 or pH 10.0 was much greater than that at acidic or neutral pH, and the maximal yield of 256.2 mg SCFAs-COD per gram of volatile suspended solids (VSS) was at pH 10.0, which was, respectively, over 3 and 4 times that at pH 5.0 and uncontrolled pH. Clearly, SCFAs production from excess sludge could be significantly improved and maintained stable by controlling the fermentation pH at 10.0. The composition of SCFAs and the percent distribution of individual SCFAs accounting for total SCFAs at pH 10.0 were analyzed. The SCFAs consisted of acetic, propionic, iso-butyric, n-butyric, isovaleric, and n-valeric acids, and acetic acid was the most prevalent product with a fraction of 40-55%. Because the results of this study were different from those of previous studies of SCFAs production, the mechanism of increased SCFAs production under alkaline conditions was investigated. Results showed that as soluble COD increased, more soluble protein was provided as the substrate for producing SCFAs. In addition, less or even no SCFAs were consumed by methanogens at alkaline pH, so the SCFAs production was therefore remarkably improved. Further investigation revealed that the formation of SCFA at pH 10.0 was dominated by biological effects rather than by chemical hydrolysis.