Gravity-Powered Water Treatment Plant

Many Central American towns and cities are fortunate to have an abundance of water sources located in the surrounding mountains.  So a lot of times the challenge is not getting water into the homes but rather cleaning that water so that it can be safely consumed by the people.

Nearly every medium-sized town (2,000 to 8,000 persons) that I have been to has relatively reliable sources of water and the infrastructure to transport that water to the townspeople.  Sources are typically mountain streams and springs captured in dams and spring-boxes.  The water is carried by metal and plastic pipes to storage tanks then to water distribution networks that serve the towns.  Traditionally, treatment consists of gravity sedimentation at the source and chlorination at the tank.  My experience is that the sedimentation is usually insufficient (under-sized sediment tanks) and that chlorination is often not done due to a myriad of factors including laziness, cost, and distaste by the community.

Many international organizations are currently experimenting with water treatment plants in developing countries.  Various possible solutions are being implemented from high-tech package plants to massive slow sand filter plants.  I have seen examples of each but neither seems to be the solution.  Package plants require tons of expensive electricity and highly trained technicians to staff the plants.  Slow sand filter plants are incredibly expensive and require large tracts of land for construction.  Both, as I have witnessed, have a life-span of about 5 years due to expensive maintenance procedures that simply are not done correctly nor frequently enough.

I have recently become part of a team with a new approach born out of university sponsored research and development in the US at Cornell University.  The project, named Agua Clara, is a partnership between the Civil and Environmental Engineering program at Cornell and a Honduran NGO – Agua Para el Pueblo (APP).  Undergraduate and graduate students at Cornell are providing the R&D and APP is implementing the technology on the ground here in Honduras.

The water treatment plants they have developed require zero electricity, two or three competent operators, and are highly effective at producing a clean drinking water for medium-sized towns at a low unit cost.  I have discussed these plants in a previous post.  More information about the technology and programs can be found at APP and Agua Clara’s websites.  The technology implements treatment processes common in US treatment plants (flocculation, sedimentation, chlorination) finely tuned to be a sustainable solution in developing countries.

I will be supporting APP and Agua Clara as they move forward with a Rotary Club-funded project in Atíma, Sta. Bárbara, about 3 hours from Trinidad.  My role is not yet completely defined, but I will likely be lending support in the area of site design through surveying and AutoCAD work as well as design plans review.

I met the students and their professor, Monroe, in Atíma where they presented the project to the town leaders and citizens.

Town Meeting

A small, functioning “pilot plant” was demonstrated for interested parties to observe.  In front of many of the people of Atíma, the students demonstrated the processes by which dirty water is transformed to agua clara.

Cornell students setting up the pilot plant before the meeting

Flocs

For most of the students, it was their first trip to Honduras and they were well received by the gracious people of Atíma.  The project is scheduled to be under construction in the first trimester of 2011 and I will continue to post as the project moves forward.  Here are a couple more pictures from my trip to Atíma…

Crazy tree in the park in San Nicolas, on the way to Atima

View from one of the water sources above Atima