blueEnergy Experiments with its First Solar Latrine

By Andrew Peterson and Mark Allison -- As the world population approaches eight billion people, basic sanitation and waste management will become an increasingly difficult and important topic. Mismanagement of waste can contaminate potable water sources, spread disease and contribute to diarrhea, the second leading killer in developing countries. To address this issue in the Bluefields community, blueEnergy gave Service Learning (SLI) interns, Mark Allison and Andrew Peterson, the task of implementing  solar latrines into the water and sanitation department of blueEnergy. Overall the goal is that solar latrines will help offer a sustainable and sanitary solution to waste management in Bluefields.

Many latrines in the Bluefields community are basic pits dug into the ground and have the possibility of contaminating gound water sources, affecting the families that use them. This was the case with the family that was selected to be the first beneficiaries for a blueEnergy solar latrine. The family was selected due to their location (solar radiation, a garden, no close ground water source, and available space for construction), their interest in the solar latrine project and the need for a more sanitary waste management system. The latrine that the beneficiaries were using before blueEnergy’s project was a rustic latrine that had one pit for garbage, solid, and liquid waste. The rustic latrine also did not have adequate walls for privacy or ventilation for bugs and smell.

fig 1. Solar Latrine Beneficiaries

fig 2. Rustic Latrine previously used by the Beneficiaries

As mentioned before, solar latrines are sustainable and sanitary. Using a solar collection chamber (fig. 3) human waste is cooked and dried, effectively killing any harmful bacteria and leaving rich compost that can be used to improve crop yields. The chamber is divided into three sections into which waste is raked every 15 days. To make sure that the human waste dries completely, the solar latrine has a toilet bowl that contains two different bowls (fig. 4). Solid waste goes into the larger back chamber, while liquid waste goes into the front bowl and then into a separate pit outside the latrine (fig. 5).

fig 3. Solar collection chamber

fig. 4 Toilet seat with divisions

fig. 5 Urine filtration chamber

In the following weeks blueEnergy will be performing follow up evaluations and further education with the beneficiaries. As part of the contract that was signed, blueEnergy will be permitted to make regular visits to the site to take temperature readings of the chamber, evaluate the compost and make sure that the beneficiaries are using the latrine correctly. Depending on the outcome of these visits blueEnergy will be able to determine if solar latrines are successful in Bluefields or if a different type of latrine should be built and tested by future SLI’s.

Mark and Andrew and future latrine builder