Migration of rare and abundant species, assembly mechanisms, and ecological networks of microbiomes in drinking water treatment plants: Effects of different treatment processes

Microorganisms play an important role in the degradation of pollutants. However, they also cause problems in drinking water distribution systems, such as pipe corrosion and biofilm growth. The microbial assembly mechanisms and molecular ecological networks associated with different drinking water treatment processes have not yet been clearly analyzed. Therefore, this study investigated the microbiomes of three processes (coal filtration–activated carbon, ozone–activated carbon and UV, and ozone–activated carbon) during different seasons. The results showed that the microbial composition and diversity among the different processes and during different seasons. Water treatment processes had deterministic effects on the microbial assembly process and significantly changed the composition of rare and abundant species, altering the size and modules of molecular ecology networks. Rare species considered as keystone species play important roles in microbial ecology and microbial community construction. Ozone–activated carbon and UV/chlorination decreased the bacterial concentration, increased the deterministic process of microbial assembly, and significantly reduced the size of the network, which is of great significance to microbial control in drinking water. This research broadens our perspectives on the microbial assembly associated with drinking water treatment processes and contributes to ensuring the safe supply of drinking water.