生物产酸对木薯酒精废水发酵联产氢气和甲烷的影响

Effects of biogenic acid production on co-production of hydrogen and methane from cassava alcohol wastewater fermentation

在温度为36.0±0.5℃,初始pH值为4.5,5.5,6.5和7.5条件下进行生物产酸过程,当初始pH值为6.5,获得最大生物产酸率为53.13%,产酸过程进行168 h后再进行厌氧消化过程。用修改的Modified Gompertz模型处理两级厌氧消化与直接厌氧消化的实验数据,获得最大比产气量、最大比产气速率和滞留时间等厌氧消化动力学参数。拟合结果表明,初始pH值为7.5,6.5和5.5实验组的两级厌氧消化比直接厌氧消化的产气效果好,初始pH值为4.5的两级厌氧消化产气效果相对较差。初始pH值6.5的实验组产气效果最优,以单位质量MLVSS计的最大比产氢量和最大比产甲烷量分别为90.63 mL/g和199.33 mL/g。以单位质量MLVSS计的最大比产氢速率和产甲烷速率分别为13.00 mL/(g·h)和1.37 mL/(g·h)。两级厌氧消化比直接厌氧消化处理木薯酒精废水的能源转化率提高了19.01%。

The process of biological acid production is carried out at different initial pH values(4.5,5.5,6.5,7.5)at 36.0±0.5℃,respectively.The maximum biological acid production rate was53.13%when the initial pH value was 6.5,the acid production process was 168 h before the anaerobic digestion process.Experimental data of two-stage anaerobic digestion and direct anaerobic digestion were treated with Modified Gompertz model,and anaerobic digestion kinetic parameters such as maximum specific gas production rate,maximum specific gas production rate and retention time were obtained.The fitting results show that the two-stage anaerobic digestion with initial pH value of 7.5,6.5 and 5.5 has better gas production effect than direct anaerobic digestion,while the two-stage anaerobic digestion with initial pH value of 4.5 has a relatively poor gas production effect.The gas production effect of the experimental group with initial pH value of6.5 was the best,and the maximum specific hydrogen production and methane production per unit mass of MLVSS were 90.63 m L/g and 199.33 m L/g,respectively,and the maximum specific hydrogen production rate and methane production rate per unit mass of MLVSS were 13.00 m L/(goh)and 1.37 m L/(goh),respectively.The energy conversion rate of cassava alcohol wastewater was 19.01%higher when we used two-stage anaerobic digestion compared with direct anaerobic digestion.