Modeling the Tradeoff Between Water Loss, Chlorine Residuals, and Trihalomethanes in Rural Appalachia, USA

Area of Science:

• Environmental Engineering
• Water Resource Management
• Public Health

Background:

• Small rural water utilities, particularly in Appalachia, face significant water loss challenges.
• Maintaining water quality compliance is a persistent struggle for these utilities.
• Extreme water loss impacts both system efficiency and public health outcomes.

Purpose of the Study:

• To quantify the effects of reducing water loss on water quality within a rural distribution system.
• To model the impact of various water loss reduction scenarios on chlorine residuals and trihalomethane (TTHM) formation.
• To assess the trade-offs between water loss reduction and water quality compliance in challenging environments.

Main Methods:

• Development and validation of hydraulic and water quality models using EPANET and KYPIPE.
• Simulation of water loss reduction scenarios from 70% to 15%.
• Analysis of impacts on chlorine residuals and TTHM concentrations under different operational conditions.

Main Results:

• Reduced water loss increased water residence times, leading to significant declines in chlorine residuals (22-68%).
• TTHM concentrations increased by 12-44%, with some sites exceeding the maximum contaminant level.
• Water quality degradation occurred as a consequence of water loss reduction efforts.

Conclusions:

• Reducing water loss can unintentionally compromise water quality in rural distribution systems.
• Integrated planning is essential to balance water loss reduction with water quality maintenance.
• Mitigation strategies include operational adjustments, source water management, and infrastructure upgrades.