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.