油脂对餐厨废弃物单相厌氧定向制酸的影响

通过间歇实验研究了油脂对餐厨废弃物单相厌氧定向产酸(VFA)的影响.考察了油脂含量为0.0,5.0,15.0及25.0g/L条件下发酵液中有机酸浓度及组成的变化情况.结果表明,油脂对发酵液中VFA浓度影响显著,随油脂含量提高最大VFA浓度呈下降趋势,当油脂含量达到25.0g/L时,最大VFA浓度仅为23.22g/L,为未添加油脂条件下的55.3%,其次油脂可延后开始产酸的时间,油脂含量为5.0g/L时,达到最高VFA浓度50%所需的反应时间分别为49.4h相对未添加油脂组滞后27.1h.此外油脂会影响发酵液中VFA各组分比例,提高丙酸含量促使发酵类型由丁酸型发酵向丙酸型发酵转变,当油脂含量为5.0g/L时丙酸所占比例分别为32.2%,而未添加油脂组的丙酸含量仅占8.7%.

Effect of grease on acid fermentation of kitchen waste by single phase anaerobic methods

Under the optimum reaction conditions (pH 6.0, the temperature of 35 ℃), batch experiments were carried out to determine the effect of grease content on volatile fatty acid (VFA) concentration and composition during anaerobic acidogenesis of kitchen wastes. The grease content was controlled at 0.0g/L, 5.0g/L, 15.0g/L, and 25.0g/L. The results showed that, the effect of grease on VFA concentration was significantly, and maximum VFA concentration decreased with the amount of grease improved. When the amount reached 5.0g/L,15.0g/L and 25.0g/L, VFA maximum concentration reached 38.84g/L,33.88g/L and 23.22g/L, which was only 92.5, 80.7and 55.3percent of not adding grease. Second, the grease may arrest acid production, under the grease content of 5.0g/L, 15.0g/L and 25.0g/L, the half of highest VFA concentration required 49.4h, 56.4h, 58.8h, which was lag 27.1h, 34.1h, 36.5h relative to the group without adding grease. Also grease can affect the proportion of each component of VFAs. It changed acid-type from butyric acid type fermentation to propionic acid type fermentation with improving the propionic acid content. When the amount of grease reached 5.0, 15.0 and 25.0g/L, the proportion of propionic acid reach up to 32.2%, 23.0% and 20.5%, which was only 8.7percent in control experiment.