Solar powered Reverse Osmosis water purification system

Deep in the jungles of the Yucatan peninsula, residents of the remote Mexican village of La Mancalona are producing clean drinking water using the power of the sun.

For nearly two years now, members of the community, most of whom are subsistence farmers, have operated and maintained a solar-powered water purification system engineered by researchers at MIT.

The system consists of two solar panels that convert sunlight into electricity; these, in turn, power a set of pumps that push water through semiporous membranes in a filtration process called reverse osmosis. The setup purifies both brackish well water and collected rainwater, producing about 1,000 liters of purified water a day for the 450 residents.

Since the PVRO system was installed, the village has been operating it as a business, selling 20-liter bottles of water to residents for 5 pesos — a price that the community agreed upon, and about one-tenth the price of bottled water that is intermittently supplied by a centralized facility an hour’s drive from the village.

At this price, the community reaps a profit of about 49,000 pesos, or $3,600, per year. The community has appointed a committee to manage the incoming funds, setting aside some money for maintenance and repair of the system, and investing the rest back into the community.

“They’re also trying to develop a business plan focused on selling clean water to tourists who come to the local Mayan ruins,” Elasaad says. “So it’s been interesting seeing what they’ve done with this new economy.”

She adds that the residents in La Mancalona have taken ownership of the technology, having been trained to operate it on a day-to-day basis, from changing out ultraviolet lights and filters to testing the water quality and replacing batteries.

The MIT-developed system is located next to a government tower that contains undrinkable water, and only intermittently. Photo: Field and Space Robotics Laboratory/Fondo Para La Paz

Desalination Journal – Field evaluation of a community scale solar powered water purification technology: A case study of a remote Mexican community application

Highlights
• PVRO water purification system is designed and tested in rural Mexican community.
• The technical and economic feasibility of approach under field conditions is shown.
• Community members are successfully trained to operate and maintain the system.
• The work suggests that PVRO clean water is a viable approach for rural communities.

Abstract
Lack of clean water in small remote communities in the developing world is a major health problem. Water purification and desalination systems powered by solar energy, such as photovoltaic powered reverse osmosis systems (PVRO), are potential solutions to the clean water problems in these small communities. PVRO systems have been proposed for various locations. However, small PVRO systems with production on the order of 1 m3/day for remote communities present some unique technical, cost and operational problems. This paper reports on a project in which a PVRO system is designed, fabricated and deployed in remote village in the Yucatan Peninsula of Mexico. The community residents are indigenous people who are subsistence farmers and beekeepers. Technical and economic models used to configure the system for the community are presented. A plan is developed in cooperation with the community aimed at making the system self-sustaining in the long term. Methods and materials are developed to permit the community members to operate and maintain the system themselves. The results provide insights for the design and deployment of small community-scale PVRO systems in remote communities.

SOURCES – Technology Review, Desalination Journal