蓝藻厌氧消化产沼气技术研究

Research on Biogas Production Technology of Anaerobic Digestion with Blue-green Algae

为了实现太湖蓝藻的资源化和无害化处置,本文在中温(35℃)条件下对蓝藻与猪粪厌氧发酵产沼气进行了研究。在蓝藻与猪粪发酵最佳接种比例1∶2、最佳初始pH7.9、最适发酵液浓度2.9%条件下,通过对所产甲烷的分析,得到回归方程B=4 885(1-e-0.034 565 t),模型的决定系数R2为0.981 9,均方差(RMSE)为123,达到收敛判断标准。蓝藻的生物降解率(BD值)为54.4%。pH的变化范围在6.6～7.9之间,能够较好地反应蓝藻与猪粪混合发酵的水解阶段、产酸阶段和产甲烷阶段。发酵结束后,TS去除率达到22.2%,VS去除率达到25.2%。对发酵过程中COD和氨氮变化的研究表明:反应结束后,COD的去除率达87.44%;高浓度的氨氮对厌氧细菌的生长有一定抑制作用,但是并不影响沼气的组份。各反应器所产生的沼气中甲烷和二氧化碳的含量均能保持在50%和35%左右,最高甲烷含量达到70%。

This paper studies the biogas production method of digesting blue - green algae and pig manure at 35 ℃ anaerobi- cally in a bid to recover and treat the blue - green algae salvaged from Taihu Lake. Under the optimum conditions of inoculation proportion 2 ： 1, initial pH 7.9 and fermentation concentration 2. 9%, the biogas production process complied with the regression equation B = 4885 （ 1 - e-0.034565t）. The determination coefficient（ R2 ） between the model and experiment was 0. 981 9 with the mean square error（RMSE） 123, which came up to the convergence criteria. The biodegradation rate （BD）of blue - green algae reached 54. 4%. The pH changed from 6. 6 to 7.9, reflecting the three stages of hydrolysis, acidification and methanogenesis in the anaerobic digestion. After the anaerobic digestion, TS degradation rate reached 22.2% and VS degradation rate reached 25.2%. COD degradation rate could reach 87.44% after fermentation. The results showed that high concentration of ammonia had inhibitory effect on anaerobes growth to a certain extent. However, it didn＇t influence the biogas composition. The contents methane and carbon dioxide of biogas could be maintained at 50% and 35%, and the highest methane content could reach 70%.