A new international study indicates that a simple, automatic chlorine dispenser can have a major impact on childhood diarrhea in the developing world. By applying water disinfectant that doesn't adversely affect taste at the point of dispensation for shared urban water systems, rates or diarrhea were reduced by 23 percent in a test project in Bangladesh.

Poor water quality is a major problem in many regions of the developing world, resulting in diarrhea being the second leading cause of child death globally. We tend to think that this is confined largely to rural areas, but many cities also suffer from this scourge.

Water systems in the West not only carry water that has been purified and treated by various means, it's also carried in pressurized pipes that go straight to the household and keep the water circulating at all times. However, more primitive systems found in cities in many developing countries may not only carry untreated water, but are unpressurized systems where water can sit stagnant. The result is one billion people drinking water that does not meet international safety standards and has twice the level of contamination to that found in rural sources.

According to Stanford University, there have been a number of attempts to address this problem, but many of these rely on adding chlorine to the water at home, which requires conscious effort and the resulting bad taste of chlorine is off-putting. Instead, the new study led by Stanford epidemiologist Stephen Luby went for an automatic approach at the point where the water is collected – usually a group tank fed by a standpipe.

In this, the researchers installed by the tap a device made by Aquatabs Flo that uses a stack of chlorine tablets that rests on top of the water flow. As the water runs into the tank, the chlorinating mixture is dissolved and decontaminates the water. It's a system that uses no electricity, has no moving parts, and is entirely passive in function. It also means that the people using it don't need to alter their daily routine.

For the study, the Stanford team worked with two poor communities in the slums of Dhaka, Bangladesh. The people were first polled to determine how much chlorine could be added to the water before it tasted bad. Then one set of tanks was equipped with the chlorine tablets and the other with vitamin C as a control group.

The next step was to let the communities get used to the taste of chlorinated water and then upping to dosage until the taste was still acceptable, yet would be four times more likely to kill diarrhea-causing E. coli bacteria.

The study found that out of 1,000 children, the chlorinated water drinkers had 23 percent lower rates of diarrhea than the control group, indicating the practicality of the system. Stanford says that the technology is currently designed to be used with storage tanks, but that Stanford and Tufts University are working on a new system that can be installed on any tap.

The research was published in The Lancet Global Health.