BOGOTÁ — The Alba Torres family has already gotten top global recognition for one bright and simple idea to help support water conservation. But their work continues, recently helped by 30 high school students from in and around Bogota, they are installing another built-in wall system to collect rainwater and drain it into plastic bottles for reuse.

I am even finding websites in Russian explaining how to make an Ekomuro.

I met the father of the family, Ricardo Alba, in his office, where he points out the prize that has helped spread his idea around the world. The prize itself doesn't appear particularly impressive — just a small, wooden box. But it was the World Water Council award, recognizing his Ekomuro — or "ekowall" — rainwater harvesting system, as the most innovative idea of 2015.

Ekomuro won the prize over nine other environmental projects that year, with a system for using recyclable plastic bottles so efficiently and economically to both conserve water and limit bottles winding up floating as trash in the seas. The 2015 prize was a boost to the project, and Ricardo Alba is now taking Ekomuro to Honduras, Guatemala and Brazil, with plans also in Africa. "Look I am even finding websites in Russian explaining how to make an ekomuro, with drawings and instructions, step by step," he says.

A simple and almost self-evident structure

Ekomuro was born in 2008 when Alba was working with his son Ricardo on a solar heater made of recycled materials, for presentation at his school. His corrugated plastic (Kartonplast) heaters were a contraption he had already installed in 15 homes in the southern Puente de Aranda district in Bogotá . "We wanted to complement the water heating project and thought, instead of storing the water in a tank, we could keep it in used plastic bottles. These bottles were later used to make Ekomuro," he says.

The simple and almost self-evident structure is what drives the innovation in this case. Each module consists of 54 soft drink bottles of 2.5 or 3.0 liters, linked with their caps, which are perforated and melded by heat. Water enters the system through tubes on the roof. The first bottles to fill are those with PVC bases, and one bottle is fitted with a tap. Each Ekomuro keeps up to 162 liters of rainwater, but as they are quite compact, a school can install five or six or more of the systems.

Ekumuro in construction in Mandalay Bogotà Photo: Ekomuro H20+ Facebook page

The first wall was installed in 2009 at the school where Ricardo's wife, Nancy Torres, teaches natural sciences. The idea, says Ricardo, was "for the children to build it: the materials are brought in from home or the school, then you explain in a workshop how to build it. They will find some of their problems from physics, chemistry and math."

Now 30 schools in Bogotá have these bottle walls, and the family says it loves to share each stage of the process with students. In 2011, the project received its first award, given by the Colombian education ministry. The schools that installed them won the country's Cultura del Agua (Water Culture) prize that year. The project has won more prizes and recognition since then, including a nomination for Scientific American's Science in Action prize, and a Pepsi Cola prize for environmental innovation in 2013. Pepsi's $5,000 prize allowed 15 Ekomuros to be created on the highest cliffside of Cazucá, a poor neighborhood with no running water, an initiative that was in turn nominated for a UN Habitat prize in 2014.

Built for sharing

By now, Ricardo Alba and his family have lost count of how many places and people have contacted them. But the project is built for sharing. "This is for all the world," Alba says, though he admits he is upset if others make money from it or if he is not mentioned when the project is rewarded. Still, he says, "it's great to see it everywhere."

The latest email to arrive was from Martin Vincent, a scientist from Waterspoutt, an EU-funded project that has brought drinking water to five million Africans using plastic bottles and water that is disinfected by exposure to the sun's rays. Alba shows me the message where Vincent asks how to connect the bottles together in order to build a wall of them exposed to the African sun. Simple ideas are often the ones that travel farthest.

See more from Tech / Science here