pH对厨余垃圾发酵产酸特性影响的研究

采用锥形瓶反应器及室内培养方法,研究了pH对厨余垃圾酸化的影响。结果表明,酸化产物的组成与pH有关,乳酸和乙酸在不同的pH值下总为主要产物;pH>7时,明显有丙酸生成;酸化的最佳pH值为7,此条件下VFA的产量最高可达35.1gVFA·L-1,总固体(TS)的去除率高达65.3%。

Effects of Acidity on Fermentation of Kitchen Wastes

Selective production of kitchen wastes by anaerobic acidogenesis with pH control was examined in the present study. It has been stated that anaerobic acidogenesis is regarded as the first step in anaerobic digestion of soluble organic materials to methane and CO2. Many kinds of bacteria are involved in the acidogenesis, subsequently, several kinds of organic acids and alcohol are usually produced. Since composition of organic acids in the medium influences the quality of biodegradable kitchen wastes by fermentation, it is important to control the product spectrum during anaerobic acidogenesis. The results in this study showed that the product spectrum in the acidic reactor was strongly depended on cultural pH. Acetic and formic acid were the main products under different cultural pH, while propionic acid was apparently produced under the basic condition, and the butyric acid was examined obviously under acidic and neutral conditions. The change in main products was caused by change in the dominant microbial populations, from butyric acid-producing bacteria to propionic acid-producing bacteria in the acid reactor due to pH shift. Additionally, the optimum pH was found to be 7, under which, the production rate of VFA was 35.1 g VFA/L, and remove rate of TS was 65.3%. The control of cultural pH was considered to be a useful way in controlling product spectrum in the anaerobic acid reactor.