餐厨垃圾性质自调节提高厌氧发酵产甲烷研究

Self-conditioning of food waste properties to improve methane production in anaerobic digestion

通过配伍不同来源垃圾调节餐厨垃圾性质(自调节)优化厌氧发酵,可突破传统的外源物质调节餐厨垃圾性质的局限性。采用响应曲面法通过3因素3水平的中心复合设计进行批式厌氧消化,研究餐厨垃圾性质优化以获得最佳产甲烷效能,其中以甲烷产量作为响应因子,并分别选取果蔬类占比(干重质量分数)、含水率和碳氮质量比(C/N)作为餐厨垃圾影响因素(其取值以福州市餐厨垃圾变化范围为基准)。结果表明,当餐厨垃圾C/N为14.92、含水率为92.0%时,果蔬类占比为49.0%,以挥发性固体(VS)计甲烷产量最高,为431.74 mL/g;果蔬类占比为70.0%,以干重计甲烷产量最高,为311.51 mL/g。方差分析证明,含水率和果蔬类占比对甲烷产量和有机物降解量具有显著影响,而C/N及两两因素交互作用均不显著。相关性分析表明初始VS浓度、VS降解量与甲烷产量均呈显著正相关,而VS降解率与甲烷产量相关性不大。有机质降解量较高的体系,甲烷产量较高,与产甲烷规律相符。

Optimized anaerobic digestion with different waste to regulate the properties of food waste(self-conditioning)can break through the limitations of traditional exogenous substances to regulate the properties of food waste.A response surface methodology was used for batch anaerobic digestion through a three-factor,three-level central composite experimental design to study the optimization of food waste properties to obtain the optimal methane yield,in which methane yield was used as the response factor,and the proportion of fruits and vegetables(mass fraction of dry weight),moisture content and C/N mass ratio(C/N)were selected as the influencing factors of food waste,respectively(the values were based on the range of variation of food waste in Fuzhou City).The results showed that the highest methane yields of 431.74 mL/g(by volatile solids(VS)calculation)and 311.51 mL/g(by dry weight calculation)were obtained when the C/N of food waste was 14.92,the moisture content was 92.0%,and the proportion of fruits and vegetables was 49.0%and 70.0%,respectively.The moisture content and the proportion of fruits and vegetables had a significant effect on methane production and organic matter degradation,while C/N and the interaction between the two factors were not significant as evidenced by analysis of variance;correlation analyses showed a significant positive correlation between the initial VS concentration,the amount of VS degradation and the methane yield,and the correlation between the VS degradation rate and the methane yield was not significan.The methane production was higher in the system with higher organic matter degradation,which was consistent with the methane production pattern.