猪粪与鲜红薯藤不同配比中温厌氧发酵特性

Analysis of the mesophilic anaerobic fermentation characteristics of pig manure mixed with the fresh sweet potato vine in different ratios

为了研究中温条件下猪粪与鲜红薯藤不同配比对厌氧发酵特性的影响及各指标的变化规律,在35℃恒温、总固体质量分数8%条件下,猪粪与鲜红薯藤按质量比2∶1、1∶2、1∶3进行厌氧发酵试验,试验结果用SPSS 22和Excel进行统计学分析。结果表明,猪粪与鲜红薯藤混合厌氧发酵最佳效果的配比是1∶2,其最大甲烷体积分数是56.5%,累计产气量为10 033 m L,这比2∶1和1∶3分别高出33.9%和17.8%。各组的累计产气量、挥发性脂肪酸(VFA)质量浓度和甲烷体积分数两两之间均出现显著性差异(p<0.05)。各配比的p H值、VFA与甲烷体积分数之间呈动态相关。

This paper intends to make an investigation of the anaerobic fermentation characteristics of the pig manure mixed with the fresh sweet potato vines in different mixed ratios so as to improve the biogas yield as a result of the fermentation. The experiment results we have gained through an anaerobic digestion reactor at the temperature of 35 ℃ in the different distribution ratios of 2： 1,1： 2 and 1： 3 between the pig manure and the fresh sweet potato vine,at a total solid concentration（ TS） of 8% in the reactor. Then we have made an analysis of such indicators,such as the daily gas production,the cumulative gas production and the VFA concentration,p H value and the methane volume fraction,so that each of the tests can give out the biogas yield. And,then,we have managed to work out the greatest cumulative biogas yield of 10 033 m L in the mixture of pig manure and fresh sweet potato vine at a ratio of 1： 2,which has been found increased by a percentage of 33. 9% and 17. 8% as against the ratio of 2： 1 and 1：3,correspondingly,with the maximum daily gas yield being 820 m L in the above test. Nevertheless,it has been found that,with the reduction of the pig manure content,the time to reach the maximalist daily gas production in each group has been found slightly delayed. That is to say,both of the cumulative gas production and the average p H value may tend to increase first and then decrease whereas the average VFA concentration tends to decrease at first and then begins to increase. But,in contrast,p H value can be found in significantly negative correlation with the VFA concentration（ p 0. 01）,for example,the p H value has a significantly positive correlation with the methane volume fraction（ p 0. 01）,whereas the VFA concentration is negatively correlated with the methane volume fraction（ p 0. 01）,though not significant correlation has been noticed between the daily gas production and the other indicators related. Thus,it can be concluded that there may always exist significant gaps among the cumulative gas production,the VFA concentration and the methane volume fraction（ p 0. 05）.