有机负荷对秸秆床反应器厌氧生物产沼气的影响

在实验室条件下,以打捆麦秸为固定相,以猪场废水为流动相,采用半连续进料方式,考察了不同猪场废水容积负荷对秸秆床反应器产沼气的影响.结果表明:发酵前25d,较高的猪场废水有机负荷对反应器产气有一定抑制,之后日产气量和容积产气量迅速增加,并明显高于低猪场废水有机负荷的处理,当猪场废水容积负荷为7.2kgCOD/(m3×d)时,厌氧反应器最大容积产气量达2.29m3/(m3×d),产气稳定后维持在1.52~1.76m3/(m3×d),较猪场废水容积负荷为2.4,1.44kgCOD/(m3×d)的处理分别提高了50%和130%以上,对产气中甲烷含量无明显影响;较高的猪场废水容积负荷不利于麦秸厌氧发酵产沼气,发酵后麦秸干物质损失率、纤维素和半纤维素分解率均与猪场废水容积负荷成反比,红外的结果与之一致.对发酵后麦秸水浸提液的DGGE检测表明,维持反应器高有机负荷、低发酵液HRT,促进了厌氧微生物在麦秸表面定植,微生物种群数量和丰富度均明显高于低有机负荷、高发酵液HRT的处理,反应器耐高有机负荷冲击的能力增强.采用秸秆床反应器处理农村常见的秸秆和畜禽养殖污水产沼气是可行的,且较高的废水有机负荷有利于提高反应器容积产气率.

Effect of organic loading rate of piggery wastewater on biogas production of straw-bed bioreactor

Influence of organic loading rate (OLR) of piggery wastewater on biogas production of straw-bed bioreactor was conducted under (37±1)℃ at lab scale. Higher OLR of piggery wastewater was adverse to biogas production during day 0to 25, and then daily biogas yield and volume biogas yield increased rapidly and higher than that of treatment with lower organic loading rate of piggery wastewater. The highest volume biogas yield of 2.29m3/(m3·d) was obtained at 34d with OLR of piggery wastewater of 7.2kgCOD/(m3·d). Volume biogas yield of treatment with OLR of piggery wastewater of 7.2kgCOD/(m3·d) was 1.52~1.76m3/(m3·d) which was 50% and 130% higher than that of treatment with OLR of piggery wastewater of 2.4and 1.44kgCOD/(m3·d). The higher OLR of piggery wastewater was adverse to biogas production of wheat straw and higher OLR of piggery wastewater with lower total solid, cellulose and hemicelloluse removal rate which was consistent with the result of FTIR. The result of DGGE of water extract of digested wheat straw showed that higher OLR of piggery wastewater promoted the colonization of microorganisms in the straw surface and anaerobic microbial community structure and number were much more than that of treatment with lower organic loading rate of piggery wastewater. It was feasible to use straw-bed bioreactor for biogas production with agricultural straw and livestock wastewater as fermentation materials and higher OLR of livestock wastewater with higher volume biogas yield.