Evaluation of System-Level, Passive Chlorination in Gravity-Fed Piped Water Systems in Rural Nepal

Area of Science:

• Environmental Engineering
• Public Health
• Water Treatment Technologies

Background:

• Globally, over 2 billion people lack access to safely managed drinking water.
• Household-level water treatment products often rely on user behavior, limiting effectiveness.
• Passive chlorination offers a potential alternative for system-level water treatment, reducing reliance on individual actions.

Purpose of the Study:

• To evaluate the performance, cost, and user acceptability of passive chlorination technologies for system-level water treatment.
• To assess the impact of passive chlorination on water quality in small, rural piped water systems.
• To provide data on the long-term effectiveness and economic viability of passive chlorination in resource-limited settings.

Main Methods:

• A nonrandomized evaluation of two passive chlorination technologies was conducted in six gravity-fed, piped water systems in western Nepal.
• Water quality indicators, including Escherichia coli (E. coli), were monitored at multiple points (upstream, taps, households) over one year.
• User acceptability and maintenance costs were also assessed.

Main Results:

• Baseline E. coli contamination exceeded 80% in tap water samples.
• After one year of passive chlorination, E. coli was detected in only 7% of tap samples, a significant reduction.
• Despite tap water improvements, 29% of household stored water remained positive for E. coli.
• The cost of chlorine was between $0.06-$0.09 USD per cubic meter, comparable to monitoring technology installation costs.

Conclusions:

• Passive chlorination technologies demonstrate a high potential for improving drinking water quality at the system level in rural communities.
• While effective at the tap, further interventions are needed to address contamination in household water storage.
• Successful implementation requires integrated approaches including safe storage, robust service delivery models, and reliable supply chains.