Prediction of Disinfection By-Product Formation Potential from Biofilm Chlorination in Plumbing Systems by a One-Dimension Model

Biofilms have been mainly recognised as pathogen reservoirs. Organic matter associated with biomass has also been identified as disinfection by-product (DBP) precursor. Then, it is important to understand the role of biofilms in this process in drinking water distribution networks (DWDNs) to assess the potential health risks associated with additional DBP production and exposure. This work presents a one-dimensional model to simulate the formation potentials of two DBP species in DWDNs resulting from biofilm interactions with chlorine. Following comparison with laboratory and field data, a parametric study was conducted under a range of plumbing system conditions, which are characterized by high surface to volume (Surf/Vol) ratio and high stagnation times. Analysis considering drinking water regulations from the UK and Colombia showed that increasing the pipe diameter from ½ inches to ¾ inches could reduce average chloroform and DCAN concentrations by 51% and 36%, respectively. This model allows identification of the most significant parameters that influence DBP formation resulting from biofilm chlorination in DWDNs and better understanding of the parameters interaction. The results from this study can inform guidelines for the design and operation of plumbing systems. This model can be applied and further developed by researchers and water operators.