有机成分比例对高固体浓度厌氧发酵产甲烷的影响

在12%高固体质量分数和中温(35± 1)℃条件下,开展了碳水化合物、蛋白质和脂肪不同比例联合厌氧发酵对产气性能和有机质降解过程影响的研究.结果表明,当3种有机质比例为55:36:9时,每gVS最大产甲烷量、最大比产甲烷速率、实际甲烷产率分别为404.1mL/gVS、11.2mL/(gVS·d)和326.7mL/gVS,皆高于其他有机质比例,并且有机质的降解过程更为高效、稳定.适当添加碳水化合物一方面能够提升自身的降解率,另一方面促使蛋白质和脂肪的进一步降解.当碳水化合物质量百分比高于65%时,总酸、单酸和分子态酸浓度的增加成为发酵过程的抑制因素.蛋白质质量百分比越高,发酵启动时间和发酵周期相应延长,其质量百分比高于48%时,总氨氮和游离氨对产甲烷过程造成一定抑制作用.

Effects of organic substance mixing ratios on methane bioconversion through high-solids anaerobic co-fermentation

Evaluation of high-solids anaerobic co-fermentation of carbohydrate,protein and lipid at various mixing ratios was conducted at mesophilic(35℃ ± 1℃) and high-solids(12% total solids) condition.The effects of mixing ratios on methane conversion and degradation efficiency of organic substance were investigated.Results showed that the maximum values of specific methane production potential(Ps),specific methane production rate(Rs) and methane yield were all achieved at mixing ratio of 55:36:9,and they increased to 404.1mL/gVS,11.2mL/(gVS.d),and 326.7mL/gVS,respectively.Compared with other mixing ratios,the degradation process of oragnic substance was also more effective and more stable at the ratio of 55:36:9.Adding appropriate carbohydrate could not only enchance the degradation itself,but also improve the degradation efficiency of protein and lipid.Moreover,it was found that when carbohydrate in the substrate accounted for more than 65%,the high concentration of total volatile fatty acid(VFA),some single VFA and total undissociated acid became the primary factors resulting in methane production inhibition.Increasing the proportion of protein could lead to the prolonged star-up period as well as fermentation time.When protein increased up to 48%,a switch to the inhibition of methane production by total ammonia(TNH3-N) and free ammonia(NH3-N) occurred.