添加NaOH对水生植物固体厌氧发酵产甲烷的作用

为了提高木质纤维素生物质的甲烷产率,固体厌氧发酵以及预处理技术得到了广泛应用。本研究以水生植物菹草为例,探讨了厌氧固体发酵同步碱处理提高甲烷产率的可行性。采用2种来源的微生物(厌氧污泥和牛粪),初始生物质浓度为20%TS(total solid,总固体重量),考察不同的NaOH添加量(基于反应体系总TS 0%、2.0%、3.5%和5.0%)对菹草厌氧发酵产气和固体水解效率的影响。结果表明,与对照实验组相比,初始NaOH加入量为3.5%时,接种污泥和牛粪的实验组中甲烷总产量分别为787.1 mL和1 165.4 mL,与对照实验组相比(619.1 mL和834.8 mL),分别提高了27.1%和39.6%,而且接种牛粪的实验组中单位挥发性固体(VS)产甲烷率最高,为186.5 mL/g。对发酵后的木质纤维素残渣组分进行分析,结果表明,NaOH有助于促进菹草中纤维素及半纤维素的分解,以及木质素结构的破坏,从而提高了菹草厌氧发酵产气产甲烷效率。

Effects of NaOH on solid-state anaerobic digestion of Curly-leaf pondweed

To improve the methane yields of lignocellulosic biomas, the solid stare anaerobic fermentation and pretreatment processes have been applied extensively. In the current research, a type of aquatic plant, Curly-leaf pondweed, was used as the representative of lignocellulosic biomass to test the feasibility of simultaneous alkali treatment and solid state anaerobic fermentation for the improvement of methane yields. Two different kinds of inoculums, i.e. anaerobic sludge and dairy manure, were used. The initial biomass concentration was 20% based on the total solid (TS). Effects of NaOH dosages (0%, 2.0%, 3.5%, 5.0% based on the TS) on the biogas production and hydrolysis efficiency of lignocellulosic biomass were explored. Results showed that the methane production in the sludge inoculated reactor with 3.5% NaOH was 787.1 mL which was about 27.1% higher than that of the control reactor (619.1 mL), the methane production of the cow manure inoculated reactor with 3.5% NaOH was 1 165.4 mL which was about 39.6% higher than that of the control reactor (834.8 mL). The methane production per volatile solids (VS) of the cow manure inoculated reactor with 3.5% NaOH was the highest, which was 186.5 mL/g. The analysis results of lignocellulose content showed that addition of NaOH promoted the degradation of cellulose and hemicelluloses which resulted in the higher methane yield.