食物垃圾和废纸联合厌氧消化产甲烷

Methane production by anaerobic co-digestion of food waste and waste paper

以食物垃圾和废纸为原料,通过批式中温(35℃)联合厌氧消化产甲烷实验,考察了原料比例(以VS计为:100:0、83:17和62:38)和酸化阶段pH(未调节和调节pH=7.2)对消化稳定性及消化性能的影响.实验结果表明,与单独利用食物垃圾以及未调节酸化阶段pH的厌氧消化相比,调节酸化阶段pH=7.2的食物垃圾与废纸联合厌氧消化能够避免挥发性脂肪酸抑制、保证消化稳定性并提高消化性能.在调节酸化阶段pH为7.2,且食物垃圾和废纸的原料比例为83:17和62:38的2组厌氧消化实验中,产甲烷稳定时液相pH稳定在7.4～8.0,液相产物中总VFA浓度稳定在500～900mg·L-1,其中丙酸浓度为100～550mg·L-1,未检测出乙醇;累积产甲烷量(以VS计算)分别为347和247mL·g-1,生物气中的甲烷含量稳定在70%～80%,最高可达81.6%;以1gVS相当于1.1gCOD进行计算,COD去除率分别为93.2%和80.5%,用于产甲烷的COD分别占总进料COD的90.0%和64.0%.食物垃圾和废纸的最佳中温厌氧消化产甲烷条件为:原料比例83:17,酸化阶段调节pH=7.2.

Using food waste and waste paper as anaerobic co-digestion materials, batch mesophilic （35 ℃ ） experiments were carried out to investigate the effects of material proportion （100：0, 83：17 and 62：38 ）and pH adjustments at the acidification stage （unadjusted vs. 7.2 ） on the stability and performance of anaerobic digestion. Compared to the pure food waste without pH adjustment, adjusting the pH to 7.2 at the acidification stage avoided the inhibition of volatile fatty acids（VFAs）, but maintained the stability and good digestion performance. For the two digestions of material proportion （83：17 and 62：38）with pH adjustment to 7.2 at the acidification stage, the stable pHs for methane production were 7.4 - 8.0, total VFA were 500 - 900 mg·L^-1, propionic acid concentrations were 100 -550 mg·L^- 1 , and no ethanol production was detected. The cumulative methane production （calculated from volatile solids, where 1 g VS equals 1. 1 g COD） was 347 and 247 mL·g^-1 respectively, and methane contents were 70% - 80% , highest at 81.6%. The COD removal rates were 93.2% and 80.5% and the COD of methane production were 90.0% and 64.0% of total added COD, respectively. The optimal conditions for anaerobic mesophilic co-digestion for methane production were a food waste to waste paper ratio of 83：17 with pH adjustment to 7.2 at the acidification stage.