Feasibility of anaerobic digestion for the treatment of low-temperature dairy wastewater. AD of Dairy Wastewater

Successful low-temperature anaerobic digestion is underpinned by a dynamic microbial consortium, spanning numerous trophic groups, and functioning in tandem to convert complex organic pollutants into methane and CO2. In this study, the feasibility of low-temperature anaerobic treatment of dairy wastewater was assessed during a 443-day lab-scale bioreactor trial. Both the process dynamics and microbial community structure were analysed throughout a series of strategic operational changes in bioreactor configuration and temperature. Triplicate bioreactors were operated at an organic loading rate of 7.5-9 kg COD m-3 d-1. The results indicated that low-temperature treatment was feasible at 15ºC, but that reactor configuration remained extremely important. The structure of the microbial community was analysed at strategic time-points throughout the trial using a combination of quantitative real-time PCR and amplicon sequencing of the 16S rRNA genes from both DNA and RNA. The decrease in temperature, from mesophilic to psychrophilic, resulted in a significant decrease in diversity of the microbial community.

高效低温厌氧消化（low-temperature anaerobic digestion）的稳定运行依赖于动态的微生物群落（microbial consortium），该群落涵盖多种营养类群，通过协同作用将复杂有机污染物转化为甲烷（methane）与二氧化碳（CO₂）。本研究通过为期443天的实验室规模生物反应器（lab-scale bioreactor）试验，评估了乳制品废水（dairy wastewater）低温厌氧处理的可行性。研究针对生物反应器构型（bioreactor configuration）与温度的一系列战略性操作调整，全程分析了工艺动态与微生物群落结构。三组平行生物反应器在7.5~9 kg 化学需氧量（Chemical Oxygen Demand, COD）·m⁻³·d⁻¹的有机负荷率（organic loading rate）下运行。结果表明，15℃下的低温厌氧处理具备可行性，但生物反应器构型仍至关重要。本研究在试验全程的战略性时间节点，通过联合使用定量实时聚合酶链反应（quantitative real-time PCR）与针对DNA和RNA的16S核糖体RNA基因（16S rRNA genes）扩增子测序（amplicon sequencing），分析了微生物群落结构。温度从中温（mesophilic）降至嗜冷（psychrophilic）区间后，微生物群落的多样性出现了显著下降。