Journal article
Trihalomethane, haloacetic acid, and haloacetonitrile behaviors in water heater storage tanks
ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY, v 9(11), p2965
26 Oct 2023
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Increasing the operating temperature has been recommended for controlling opportunistic premise plumbing pathogen (OPPP) growth in buildings. However, tradeoffs with operation and both disinfectant residuals and disinfection byproducts (DBPs) are not well understood. Water heater storage units were operated to evaluate the impact of use pattern (high and low), operation temperature (similar to 45 degrees C and similar to 60 degrees C) and disinfectant type (chlorine and chloramines) on disinfectant residual and DBP concentrations at the showerhead point of use (POU). Control studies with chlorinated water yielded a loss of residual by 72 hours at 22 degrees C and 3 hours at 48 degrees C and 60 degrees C. In the tank heater studies, free chlorine residuals decayed to below the limit of quantitation (LOQ) for all POU samples. The concentrations of total trihalomethanes (TTHMs) and five haloacetic acids (HAA5) at the POU and control sample locations increased by factors of 2.01 +/- 0.21 and 1.46 +/- 0.11, respectively, relative to the feed and peaked at the first point that the chlorine residual was below the LOQ, indicating a chlorine-limited reaction. The TTHM concentrations did not change thereafter, just as the HAA concentrations remained unchanged at 45 degrees C, but the HAA concentrations decreased at 60 degrees C, indicating thermal degradation. Strong decay patterns were found for four haloacetonitriles (HAN4) at elevated temperatures, and the decay was faster at 60 degrees C. In the chloramination system, total chlorine decreased passing through the tank, but a detectable residual was measured in all samples. No additional DBP formation relative to the feed was found. Under all scenarios, there was no indication of a tradeoff between controlling OPPPs and DBP formation when increasing the operating temperature to 60 degrees C. The concentrations of TTHM and five HAA5 at the POU and control sample locations increased relative to the feed. Strong decay patterns were found for haloacetonitriles at elevated temperatures, and the decay was faster at 60 degrees C compared to 45 degrees C.
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Details
- Title
- Trihalomethane, haloacetic acid, and haloacetonitrile behaviors in water heater storage tanks
- Publication Details
- ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY, v 9(11), p2965
- Publisher
- ROYAL SOC CHEMISTRY; CAMBRIDGE
- Grant note
- This work was supported by the U.S. Environmental Protection Agency (Grant Number: R836880). The article has not been formally reviewed by the EPA. The views expressed in this article are solely those of the authors and do not necessarily reflect those of the Agency. The EPA does not endorse any products or commercial services mentioned in this publication. We would like to express our gratitude to Audrey Young for providing input on the experimental design and Dorothy Noble for the laboratory assistance.
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Drexel University
- Web of Science ID
- WOS:001066922300001
- Scopus ID
- 2-s2.0-85173014883
- Other Identifier
- 991021861186304721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Engineering, Environmental
- Environmental Sciences
- Water Resources