Duke Engineers for International Development - Project Honduras 2017 was the final phase of a greywater treatment project undertaken by the DEID organization in the pueblo of El Pital, Honduras in conjunction with a local NGO called Un Mundo.
In November 2016, I was selected to be a member of the project team for DEID Project Honduras 2017, set to be implemented the following summer. We were tasked to rebuild a greywater treatment system in the small village of El Pital that had been installed by DEID in previous years but was partially destroyed the previous winter by the "storm of the century." The still-intact sections of the system were further damaged by overcapacity . Our goal was to build a system that was not only more robust but could handle a higher volume of greywater runoff from the town. Before the installation of the system, greywater produced by El Pital was having adverse effects on the agricultural terraces downstream. Thus, it was imperative that at least part of the treatment system was brought back online.
Though we were a team of undergraduates, we were responsible for independently designing the engineering solution and sourcing funding for the project. We settled on a design that salvaged as much of the existing system as possible. It included a pipe system that would deliver greywater to two concrete grease traps. The grease trap designs were based off of EPA engineering drawings for rural grease traps that use fluid properties rather than pumps and filters to separate oils and sediment from the water. However, we modified the designs to use only materials that could be easily sourced in El Pital. The grease traps filter macro-particulate from the system then deliver the water to resumideros (gravel and sand filters) that remove the remaining particulate from the water.
The water draining from the system was suitable to enter the river downhill from El Pital. The entire construction process for both of the grease traps was documented such that it could be replicated by workers hired by Un Mundo after our project was complete.
A crude analysis of the water filtration results, pictured below, shows how the water progresses from a high level of contamination and sediment entering the system (left) to a low sediment level in the second chamber of the grease trap (center) to water exiting the system with qualitatively negligible levels of contamination and sediment (right).
In addition to the reconstruction of the greywater treatment system, we were asked by Un Mundo to experiment with designs for ventilated stoves that could be built for families in El Pital and the surrounding pueblos. All but a few of the families in the town rely on organic material burning stoves without ventilation. As a result, the women of the in El Pital suffer from high rates of chronic lung diseases. Building off of existing designs, we attempted to construct a low-cost stove made from clay bricks that could match the performance of existing stoves in the town while channeling smoke and pollutants out of the house. We then delivered the designs and performance data to Un Mundo for future use.
Unfortunately, DEID has been unable to return to Honduras in the years that followed our project. Un Mundo, our partner in the region, was forced to redirect its resources towards a looming battle over water rights in the region. In addition, our organization felt that there were no further engineering development projects that could be implemented in the town without raising ethical considerations around community self-sustainability. Nonetheless, we have stayed in touch with both Un Mundo and the people of El Pital.
