酸化相发酵类型对甲烷相产甲烷性能的影响

Effects of fermentation type of acidogenic phase on biomethane yield of methanogenic phase

以餐厨垃圾和稻草为原料,通过调节酸化相的pH、氧化还原电位(ORP)和进料负荷(OLR),对酸化相的产酸发酵类型和不同酸化类型的产甲烷性能进行了研究。结果表明:当酸化相的pH<4.5和ORP<-120 m V的条件下,发酵类型为乙醇型;当酸化相的pH>5.5时,发酵类型为丁酸型发酵;在乙醇型发酵和丁酸型发酵相互转换的过程中,会出现混合型发酵。从酸化效果方面来看,丁酸型发酵的产酸性能最优,酸化度为36%。同时,丁酸型发酵酸化产物的产甲烷性能最好,累计甲烷产率为535 m L·g-1VS。通过PCR-DGGE的微生物菌群鉴定结果可知,在两相厌氧消化过程中,酸化相中的优势菌种主要以拟杆菌属(Bacteroidetes)和乳酸杆菌属(Lactobacillus)为主,甲烷相中的优势菌种以乳酸杆菌属(Lactobacillus)为主。

The different acidifying fermentation type and the corresponding performance of methane yield were researched by controlling pH, oxidation-reduction potential （ORP） and organic loading rate （OLR） in acidogenic phase of digesting food waste and rice straw. The results showed that the ethanol-type fermentation was oc- curred at pH 〈4.5 and ORP 〈 -120 mV. At pH 〉5.5, the butyric acid-type fermentation was appeared. A mixed type fermentation was found in the transformation between butyric acid-type fermentation and ethanol-type fermentation. The best acidifying performance was butyric acid-type fermentation with the acidification degree of 36%. Meanwhile, the maximum total methane production of 535 mL · g-1VS was obtained from digestion of the effluent of R2. Through the analysis results of PCR-DGGE, the advantage bacteria were Baeteroidetes and Lacto- bacillus in acidogenic phase, and Lactobacillus in methanogenic phase.