污泥厌氧发酵产氢的影响因素

污水生物处理过程中产生大量剩余污泥, 通常采用厌氧发酵处理并获取甲烷气体. 产氢产酸是污泥厌氧消化过程中的一个中间阶段. 本研究考察了原污泥和经碱处理的污泥在不同初始pH(3.0～12.5)条件下的产氢效果, 以及污泥性质和污泥浓度等对产氢效果的影响. 结果表明, 当初始pH为11.0时污泥发酵的产氢率达到最大值.采用原污泥发酵产氢时, 在初始pH为11.0的条件下发酵产氢获得的最大产氢率为8.1 mL/g, 而经碱处理的污泥在同样初始pH的条件下发酵产氢可将其产氢率提高一倍左右, 达到16.9 mL/g. 污泥经碱处理后厌氧发酵4d无甲烷产生, 且可有效地降低氢气消耗的速率. 另外, 污泥的VSS/SS值过低时会大大降低污泥的产氢率, 而污泥浓度对产氢率无明显影响.

Factors of Effecting Hydrogen Production from Anaerobic Fermentation of Excess Sewage Sludge

Large amounts of sewage sludge is produced from the treatment of wastewater by biological processes, which is usually treated by anaerobic digestion to produce methane gas. Acetogenesis and hydrogen are an intermediate phase during the anaerobic digestion. Batch tests of fermentative hydrogen production under different initial pH (3.0 - 12.5) were compared using the raw sludge and alkaline pretreated sludge. The influences of the characteristics and concentration of sludge were also examined thereafter. Results show that the optimal initial pH for biohydrogen production from sewage sludge was around 11.0. Under this optimal condition, the biohydrogen yield of raw sludge was 8.1 mL/g, and it would reach to 16.9 mL/g when the sludge was pretreated by alkali. Furthermore, there is no methane generation during the biohydrogen fermentation of the alkaline pretreatment sludge in 4 days and the hydrogen consumption is also slowed down. In addition, a low VSS/SS rate will reduce the hydrogen yield, while the concentrations of sludge have no obvious compact on it.