Groundbreaking new research from York University’s Dahdaleh Institute for Global Health Research providing recommendations to improve the safety of household water supplies in refugee and internally displaced persons (IDP) camps was recently published in Water Research, the leading water science and engineering journal.
The research paper provides the first ever evidence-based guidelines for water treatment in humanitarian emergencies. Adoption of these recommendations could significantly improve the safety of the water supply in refugee and IDP camps by preventing recontamination of the water supply between distribution and consumption.
The paper is also the first to model post-distribution chlorine decay, or how chlorine levels in water decrease after it leaves the tap.
“Chlorine decay within distribution systems is well understood going back to the 1980s, but no one has ever looked at what happens to water quality after water leaves the tap of the piped network,” says Syed Imran Ali, research Fellow at the Dahdaleh Institute and lead author of the paper.
Although chlorine decay is not a concern in municipal piped water systems like those in Canadian cities, where water is used directly from the tap, it is extremely important to understand how chlorine levels decrease in water supplies in refugee and IDP camps, where water is collected from a public distribution point, transported to households, and stored and used for up to 24 hours or longer.
Chlorination is the most widely used method of water treatment in humanitarian operations because of its low cost, ease of use, and effectiveness at protecting against microbiological contamination that can cause diseases such as cholera, dysentery and hepatitis E. Currently, humanitarian organizations follow a universal guideline for chlorine levels at water distribution points given in the Sphere Handbook, which sets standards for humanitarian action in vital areas of response.
The paper presents data from field studies conducted by researchers between 2013-15 in refugee camps in South Sudan, Jordan and Rwanda. The researchers observed how water quality changed in chlorinated water supplies between distribution and consumption. They implemented a nonlinear optimization approach for the novel technical challenge of modelling post-distribution chlorine decay in order to generate estimates on what chlorine levels must be at water distribution points in order to provide sufficient protection up to the point of consumption in households many hours later.
Researchers tested their site-specific chlorine targets to see if they provide better protection of drinking water stored in the home compared to the universal target recommended in the Sphere Handbook. They found that the site-specific chlorine targets developed through their modelling approach improved the proportion of households having sufficient chlorine levels at the household point of consumption in three out of four field studies. These sites tended to be hotter and/or had poorer water, sanitation and hygiene conditions, contributing to considerable chlorine decay between distribution and consumption. The modelling approach did not work as well where chlorine decay was minimal.
The paper concludes that the current Sphere guideline does not reliably ensure household water safety in camp settings, and that chlorination levels at water distribution points in refugee/IDP camps need to be increased by varying degrees, depending on local conditions.
“In this paper, we demonstrate that the site-specific and evidence-based chlorination targets generated from our modelling approach outperform the humanitarian standard Sphere Handbook guidelines with respect to household water safety achieved, and thereby, can better protect public health during emergencies,” says Ali.
The analytical method described in the paper forms the basis of the Safe Water Optimization Tool (SWOT) launched in fall 2020 by the Dahdaleh Institute in partnership with Médecins sans Frontières (MSF/Doctors Without Borders). Using new machine learning and the numerical modelling techniques developed in this paper, the SWOT analyzes water quality monitoring data in order to generate water chlorination targets that are both site-specific and evidence-based.
This research was led by York University in collaboration with MSF/Doctors Without Borders, the UN Refugee Agency (UNHCR) and the University of California, Berkeley.
The research was funded by MSF/Doctors Without Borders, UNHCR, ELRHA/Humanitarian Innovation Fund, and the Development Impact Lab at the University of California, Berkeley.
The full research paper can be accessed online.
By Ariel Visconti, YFile communications officer