Characterization of bacterial community and iron corrosion in drinking water distribution systems with O3-biological activated carbon treatment

Bacterial community structure and iron corrosion were investigated for simulated drinking water distribution systems (DWDSs) composed of annular reactors incorporating three different treatments: ozone, biologically activated carbon and chlorination (O-3-BAC-Cl-2); ozone and chlorination (O-3-Cl-2); or chlorination alone (Cl-2). The lowest corrosion rate and iron release, along with more Fe3O4 formation, occurred in DWDSs with O-3-BAC-Cl-2 compared to those without a BAC filter. It was verified that O-3-BAC influenced the bacterial community greatly to promote the relative advantage of nitrate-reducing bacteria (NRB) in DWDSs. Moreover, the advantaged NRB induced active Fe(III) reduction coupled to Fe (II) oxidation, enhancing Fe3O4 formation and inhibiting corrosion. In addition, O-3-BAC pretreatment could reduce high-molecular-weight fractions of dissolved organic carbon effectively to promote iron particle aggregation and inhibit further iron release. Our findings indicated that the O-3-BAC treatment, besides removing organic pollutants in water, was also a good approach for controlling cast iron corrosion and iron release in DWDSs. (c) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.