Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
Water Res. 2019 Sep 1;160:249-258. doi: 10.1016/j.watres.2019.05.077. Epub 2019 May 24.
Decentralized wastewater treatment represents a promising sustainable option for future wastewater management. Blackwater collected from toilets contains high concentrations of organic matter, ideal for energy recovery using anaerobic digestion. Up-flow anaerobic sludge blanket (UASB) reactors treating conventional toilet (CT, 9 L water per flush) and vacuum toilet (VT, 1 L water per flush) blackwater with increments of loadings were successfully operated to steady state in three phases. The organic loading rates were maintained at comparable levels between the two reactors. The methanisation rates were 0.23-0.29 and 0.41-0.48 gCH-COD/gfeedCOD in the CT and VT reactors, and the COD removal rates were 72% and 89%, respectively. The enriched microbial consortia and the community dynamics under different loading phases were compared. The rank abundance distributions and alpha-diversity showed that archaeal communities were predominated by mono-enrichments in both CT and VT reactors, while bacterial communities showed lower diversity in the VT reactor. Through principal coordinates analysis (beta-diversity), clear divergences of archaeal and bacterial communities between the CT and VT reactors were revealed, and the archaeal community developed at a slower rate than the bacterial community. The enriched archaea were hydrogenotrophic methanogens, Methanolinea in the CT reactor (56.6%), and Methanogenium in the VT reactor (62.3%). The enriched bacteria were Porphyromonadaceae in both CT (15.9%) and VT (13.4%) reactors, sulfate-reducing bacteria in the CT reactor, and Fibrobacteraceae in the VT reactor (13.8%). Links between enriched consortia and ammonia stress were discussed. Isotope fraction analysis of the biogas showed a slight shift from acetoclastic methanogenesis to hydrogenotrophic methanogenesis. A closer look into the predicted metagenomic functional profiles showed agreeing results, where hydrogenotrophic methanogenesis and fhs gene abundances were higher in the VT reactor. We demonstrated that different blackwater types enriched different microbial consortia, probably due to ammonia concentrations and sulfate loadings, which should be taken into consideration for practical applications.
分散式污水处理是未来污水管理的一种很有前途的可持续选择。从厕所收集的黑水含有高浓度的有机物，非常适合使用厌氧消化进行能源回收。在上流式厌氧污泥床（UASB）反应器中，处理传统厕所（CT，每次冲洗 9 升水）和真空厕所（VT，每次冲洗 1 升水）的黑水，通过递增负荷成功地分三个阶段达到稳定状态。两个反应器中的有机负荷率保持在可比水平。CT 和 VT 反应器中的甲烷化速率分别为 0.23-0.29 和 0.41-0.48 gCH-COD/gfeedCOD，COD 去除率分别为 72%和 89%。比较了不同负荷阶段下富集微生物群落和群落动态。等级丰度分布和 alpha 多样性表明，CT 和 VT 反应器中的古菌群落主要是单种富集，而 VT 反应器中的细菌群落多样性较低。通过主坐标分析（beta 多样性），揭示了 CT 和 VT 反应器中细菌和古菌群落的明显差异，并且古菌群落的发展速度比细菌群落慢。富集的古菌是产氢甲烷菌，CT 反应器中的甲烷八叠球菌（56.6%）和 VT 反应器中的甲烷菌（62.3%）。CT（15.9%）和 VT（13.4%）反应器中都富集了产甲烷菌，CT 反应器中富集了硫酸盐还原菌，VT 反应器中富集了纤维杆菌科（13.8%）。讨论了富集菌群与氨胁迫之间的关系。沼气的同位素分馏分析表明，从乙酸营养型甲烷生成到产氢甲烷生成略有转变。更仔细地研究预测的宏基因组功能谱显示出一致的结果，其中 VT 反应器中的产氢甲烷生成和 fhs 基因丰度更高。我们证明了不同类型的黑水富集了不同的微生物群落，这可能是由于氨浓度和硫酸盐负荷的不同，这在实际应用中应该加以考虑。
