Solar-powered UV water treatment could improve health outcomes in rural Tanzania

PhD candidate Karlye Wong (CivMin) is assessing and optimizing off-grid systems for disinfecting drinking water before use

Kharumwa Health Centre in northern Tanzania uses a rainwater harvesting facility: the tank can be seen behind the main building while the solar panel used to power the UV treatment unit is on the roof. (Photo: Karlye Wong)


Karlye Wong, CivE PhD candidate.

U of T Engineering PhD candidate Karlye Wong (CivMin) is working with the Geita and Nyanghwale District Councils in northern Tanzania to develop an affordable, low-maintenance, off-grid solution for delivering clean drinking water — one that could significantly improve local health outcomes.

“When you’re feeling sick, you seek out health care. But in many parts of the world, even the local health centre doesn’t have access to clean, safe water for drinking, handwashing and hygiene, sterilization of equipment, or intravenous and oral administration of medication,” says Wong, who is supervised by Professor Ron Hofmann (CivMin).

“Lack of access to safe water exacerbates risks of infection, water-borne diseases and diarrhea. In Tanzania, a study by the National Institute for Medical Research showed that 60% of health care facilities have high degrees of unsafe microbial contamination in sample water.”

In the areas where Wong is working, health-care facilities are not connected to electrical grids or municipal water systems, and groundwater sources are limited. Patients and hospital staff often have to collect water off-site, from sometimes unsafe water sources located miles away.

In the past few years, rainwater harvesting has become a more prominent source of water for rural and off-grid contexts around the world. However, it is not normally treated due to a host of factors, including the high cost of sanitation equipment, as well as lack of access to the chemicals and expertise needed to maintain it.

One potential solution is treating the water with ultraviolet (UV) light, which is known to destroy pathogens such as viruses and bacteria. Powered by low-cost solar panels, off-grid UV treatment systems are simpler to deploy and require less maintenance than traditional chemical treatment.

As part of a pilot program, eight health-care facilities in the Geita and Nyanghwale District Councils have been outfitted with solar-powered UV systems for rainwater harvesting and disinfection. Wong and her collaborators are now leading a detailed assessment of the performance of these facilities, as well as the experiences of their operators.

Last August, Wong travelled to all eight of the rural sites to inspect the installations and replace malfunctioning equipment, and she aims to return for a second visit later this year.

Her goal is to further refine the design of these solar-powered UV disinfection systems so they can be more effective in addressing contamination, while also being adoptable and sustainable with respect to the context of the local community.

“One change we’re looking at is replacing the current set of UV lamps with light emitting diodes, or LEDs,” says Wong. “These bulbs are less costly — and require less energy and maintenance — than the existing fluorescent bulbs. They also contain no mercury, which is a health hazard.”

Wong hopes that the project will contribute to a better understanding of how off-grid communities and health services can sustain safe water quality in the face of challenges such as climate change and water insecurity.

“While this work focuses on a pilot study in Tanzania, the lessons learned will be broadly applicable to rural or off-grid communities in developing countries around the world,” says Wong.

“Working closely with local government and staff allows us to integrate community needs and long-term sustainability into this research. It’s really important that we get these details right, because there are so many places where this kind of approach could make a difference.”

By Tyler Irving

This story originally published by Engineering News