pH值调控对柑橘废渣与污泥厌氧共发酵产酸影响

为提高挥发性脂肪酸(VFA)的产量,探究了柑橘废渣和剩余污泥不同VS(挥发性固体)配比及调控发酵过程pH值对产VFA性能的影响.结果表明:调节共发酵系统pH值为6对VFA的积累有促进作用,柑橘废渣VS/剩余污泥VS为2时的最大VFA产量为11183.12mg/L,是未控制pH值组最高VFA浓度的1.75倍.柑橘废渣中的橘皮精油能抑制产甲烷过程,发酵过程控制pH值则强化这种抑制作用.加入柑橘废渣后,共发酵系统的菌群结构优势显著,产VFA相关微生物种群大量增加,而消耗乙酸的产甲烷菌群减少,从而有利于VFA的积累.研究结果将为优化柑橘废渣与剩余污泥厌氧共发酵产VFA提供理论依据.

Effects of pH on the production of volatile fatty acids from citrus waste and waste activated sludge by anaerobic co-fermentation

In order to improve the production of volatile fatty acids (VFA), the effects of different ratios of volatile solids(VS) from citrus waste and waste activated sludge and regulating pH in fermentation processes were studied. The results showed that adjusting the pH of the co-fermentation system to 6could promote the accumulation of VFA. When the ratio of VS from citrus waste and waste activated sludge reached 2, the maximum VFA yield was 11183.12mg/L, which was 1.75times higher than that without pH control. Furthermore, the essential oil from citrus waste could inhibit the methanogenic process, which was strengthened by controlling pH in the fermentation process. After adding citrus waste, the microbial community structure of the co-fermentation system showed significant advantages. VFA related microbial population increased significantly while methanogenic bacteria consuming acetic acid decreased, which was conducive to the accumulation of VFA. The results of this experiment can provide a theoretical basis for optimizing the performance of VFA production by anaerobic co-fermentation of citrus waste and waste activated sludge.