Comparison of pipe loop and pipe section reactor methods for estimating chloramine decay in harvested distribution system pipes

Itai Arbiv; Husein Almuhtaram; Robert C Andrews

doi:10.1016/j.scitotenv.2023.163722

Comparison of pipe loop and pipe section reactor methods for estimating chloramine decay in harvested distribution system pipes

Sci Total Environ. 2023 Aug 1:884:163722. doi: 10.1016/j.scitotenv.2023.163722. Epub 2023 Apr 26.

Authors

Itai Arbiv¹, Husein Almuhtaram², Robert C Andrews¹

Affiliations

¹ Department of Civil and Mineral Engineering, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4, Canada.
² Department of Civil and Mineral Engineering, University of Toronto, 35 St George Street, Toronto, ON M5S 1A4, Canada. Electronic address: husein.almuhtaram@utoronto.ca.

PMID: 37116810
DOI: 10.1016/j.scitotenv.2023.163722

Abstract

To assess chloramine decay, this study compared the use of pipe loops, which incorporate continuously flowing water, to static pipe section reactors (PSRs). Unlined cast iron (UCI) and cement-lined ductile iron (CLDI) were harvested from distribution systems. These were directly compared to virgin polyvinyl chloride (PVC) pipe at low (0.03 m/s) and high (0.09 m/s) water velocities as well as hydraulic residence times (HRT) of 6 and 24 h. Pipe material was observed to exert the greatest impact on chloramine decay, followed by flow velocity. First-order decay coefficients obtained using pipe loops were statistically similar to those for PSR trials when considering UCI and CLDI pipe, irrespective of pipe velocity or water age. Overall results suggest that the use of PSRs may serve as a viable and cost-effective alternative to pipe loops for assessing the impact of operational variables on disinfectant decay.

Keywords: Chloramine demand; Combined chlorine; Drinking water; Residual loss; Secondary disinfection.

MeSH terms

Chloramines
Chlorine
Drinking Water*
Iron
Water Supply*

Substances

chloramine
Chloramines
Chlorine
Drinking Water
Iron