The researchers studied how the microbial community in a reactor changed as it recovered its function. They used a method called ERIC-PCR fingerprinting to analyze the changes. They found that after a 10-day pause, the microbial community structure shifted, leading to improved removal of nitrogen and phosphorus. Over time, the functional microbial community was restored, the structure stabilized, and the reactor operated smoothly. When the reactor was stable, a diverse range of bacteria were present, with specific types dominating. Different microbial communities were observed in the reactor under normal and low temperature conditions.