稻秆负荷与pH对稻秆厌氧发酵产酸系统启动过程的影响

Effect of rice straw loading rate and pH on startup of anaerobic fermentation system for production of acids

为探讨稻秆负荷(即稻秆VS/污泥VSS)与发酵pH对稻秆厌氧发酵产酸系统启动过程产挥发性脂肪酸(VFAs)效果的影响,利用厌氧搅拌罐反应系统考察在不同的稻秆负荷(0.556、0.945、1.334和1.724 g/g)和不同的发酵pH(8.0、9.0和10.0)启动运行条件下的产酸性能,并分析了系统启动过程产酸与稻秆主要成分降解之间的关系。实验结果表明,VFAs浓度随稻秆负荷提高而增大,随发酵pH的升高而降低;发酵18 d时,发酵pH为9.0时,稻秆负荷1.334 g/g的产酸效果最好,VFAs浓度与稻秆产酸量分别为4 385.10 mg/L和2.19 gVFAs/g稻秆,此时半纤维素、纤维素和酸性洗涤木质素降解率分别为32.69%、22.53%和6.40%;稻秆负荷为0.945 g/g条件下,VFAs浓度在pH为8.0时达到最高值4 409.51 mg/L,此时稻秆降解量也最多,半纤维素、纤维素和酸性洗涤木质素降解率分别为28.60%、47.32%和22.69%。研究表明,稻秆负荷与发酵pH通过影响稻秆半纤维素、纤维素和木质素的降解影响稻秆厌氧发酵产酸的进程和效果。

In order to explore the effect of rice straw loading rate（namely rice straw VS /sludge VSS） and fermentation pH on the startup of the anaerobic fermentation system of rice straw for production of volatile fatty acids（VFAs）,the performances for production of acids in the startup were investigated by anaerobic stirred tank reaction systems under condition of different rice straw loading rates（0.556,0.945,1.334 and 1.724 g / g） and different fermentation pH（8.0,9.0 and 10.0）,and the relationship between the production of acids in the startup of system and the degradation of main components of rice straw was analyzed.The experimental results showed that the concentration of VFAs rose with the increase of rice straw loading rate and decreased with the increase of pH.The best result could be achieved for production of VFAs when the rice straw loading rate was 1.334 g / g at pH 9.0 after 18-day fermentation,the concentration of VFAs and the production of VFAs were 4 385.10 mg / L and 2.19 g VFAs / g rice straw,respectively,while the degradation rates of hemicellulose,cellulose and acid detergent lignin were 32.69%,22.53% and 6.40%,respectively.The concentration of VFAs could attain the summit of 4 409.51 mg / L with the biggest degradation amount of rice straw when pH was 8.0 at the rice straw loading rate 0.945 g / g,while the degradation rates of hemicellulose,cellulose and acid detergent lignin were 28.60%,47.32% and 22.69%,respectively.This research indicated that the rice straw loading rate and fermentation pH influenced the progress and performances of anaerobic fermentation of rice straw for production of acids by means of affecting the degradation of hemicellulose,cellulose and lignin.