麦秸与奶牛场废水高固体混合厌氧发酵产甲烷研究

Study on methane production of high-solid anaerobic co-digestion of wheat straw and cattle wastewater

在实验室条件下,以麦秸和奶牛场废水为原料,设计麦秸与奶牛场废水质量比1∶4(T1)、1∶3(T2)和1∶2(T3)以及对照(麦秸与水质量比1∶4(T4))4个处理,研究发酵过程中日产气量、甲烷含量、发酵前后麦秸理化特性和结构的变化.结果表明,奶牛场废水与麦秸在中温、高固体条件下,厌氧发酵可以正常进行,且产气期延长2周以上,对甲烷含量的影响不大;厌氧发酵初始TS浓度对系统产气的影响较大,麦秸产气量随TS浓度的增加而降低,以T1的产气效果最好,麦秸TS产气量为0.41 L.g-1,较T4提高了17.14%,平均甲烷含量为48.78%;厌氧发酵后,麦秸半纤维素含量大幅降低,纤维素含量少许降低,降低幅度均为T1>T2>T4>T3,木质素含量稍有增加,各处理间无显著差异(P>0.05);FTIR和XRD的结果表明,厌氧发酵后,麦秸纤维素结晶区的相对含量增加,混合发酵可以促进厌氧微生物对麦秸纤维素结晶区的破坏.将麦秸与奶牛场废水(质量比)1∶4混合发酵产沼气是可行的,且促进了厌氧微生物对麦秸有机物的分解破坏,提高了麦秸产气量.

Effects of cattle wastewater on anaerobic digestion process of wheat straw and characteristics of digestion with different ratios of cattle wastewater and wheat straw were studied to promote biogas production.Four treatments with the ratio of wheat straw to cattle wastewater of 1 ∶4（T1）,1 ∶3（T2）,1 ∶2（T3） and control（the ratio of wheat straw to distilled water is 1 ∶4,T4） were designed.The results showed that,co-digested wheat straw with cattle wastewater was viable and gas phase was extended to two weeks,and there was no significant difference among the treatments.The biogas yield of wheat straw was influenced significantly by the initial total solid loading（TSL） of wheat straw and decreased with increasing initial TSL.The highest biogas yield of 0.41 L · g-1 TS of wheat straw was obtained with T1,which was 17.14% higher than that of T4.Hemi-cellulose content of wheat straw decreased significantly and cellulose content decreased slightly after anaerobic digestion.Content of lignin increased slightly,and there was no significant difference between different treatments.The results of FTIR and XRD indicated that the crystalline of cellulous of wheat straw increased after anaerobic digestion,and co-digestion promoted the destruction of crystalline of cellulous of wheat straw.These results suggested that co-digestion of wheat straw and cattle wastewater with 1 ∶4 ratio（based on fresh weight） was beneficial to biotransformation in organic matter in wheat straw and biogas production.