料水比对农业废弃物稻草和猪粪生物预处理及厌氧消化的影响

Effect of the Ratio of Material to Water on Biological Pretreatment and Anaerobic Digestion of Agricultural Waste Straw and Pig Manure

【目的】农业废弃物刚性的纤维结构是导致厌氧消化效率低下的主要原因,通常通过生物预处理手段来可破坏其刚性的纤维结构,而料水比是影响生物预处理效果的显著因素之一,为此,需探究料水比对稻草和猪粪生物预处理及厌氧消化的影响。【方法】控制料水比为7%、11%、15%和19%,经过前期构建的纤维素降解复合菌系进行生物预处理,并将复合菌系预处理后的稻草和猪粪混合物进行厌氧消化。【结果】控制料水比为11%时预处理液中滤纸酶活和羧甲基纤维素酶(CMC酶)酶活最高,分别为0.901 IU和1.197 IU。此外,在此料水比条件下进行预处理的稻草和猪粪混合物厌氧消化效果最佳,其累积甲烷产量和甲烷产率分别为1 778 mL和283.12 mL/(g·VS),比未经复合菌系预处理的稻草和猪粪均提高了41%,且其第1天便进入产气高峰期,日产气峰值(153 mL)最高,高峰持续时间(7 d)最长。【结论】当料水比控制在11%时,稻草和猪粪经过生物预处理后能显著提升其后续厌氧消化的效果。本研究表明生物预处理在农业废弃物的沼气资源化方面具有巨大的利用潜力。

[Objective]The rigid fibrous structure of agricultural wastes is the main cause of their low efficiencies of anaerobic digestion.Usually,biological pretreatment method can undermine their rigid fibrous structures,and the ratio of material to water is regarded as one of the significant factors affecting the effects of biological pretreatment,therefore,it is very necessary to explore the effect of the ratio of material to water on the biological pretreatment and anaerobic digestion of rice straw and pig manure.[Method]Biological pretreatment was carried out by controlling the ratio of material to water at 7%,11%,15% and 19% using a previously developed cellulolytic microbial consortium.Following that,anaerobic digestion of the straw and pig manure mixture pretreated by the microbial consortium was further carried out.[Result]The results showed the filter paper enzyme activity and carboxymethyl cellulose enzyme activity(CMCase)were the highest in the pretreatment solution when the ratio of material to water was kept at 11%,which could reach 0.901 IU and 1.197 IU,respectively.In addition,it was found that the anaerobic digestion of the straw and pig manure mixture pretreated by the consortium under the current ratio of material to water condition was the best,where the cumulative methane yield and methane yield could reach 1 778 mL and 283.12 mL/(g·VS),respectively,which were both 41% higher than those of the control without biological pretreatment.Meanwhile,the peak gas production(153 mL)was the highest on the first day and the peak duration(7 d)was the longest.[Conclusion]When the ratio of material to water was kept at 11%,the anaerobic digestion effect of rice straw and Pig manure could be significantly improved after being biological pretreated.This study indicates that biological pretreatment has great application potential in the biogas reclamation of agricultural wastes.