For this upcoming summer, Engineering Without Borders plans to travel to Zambia. A major project we have been working on is a VIP latrine, or a ventilated improved pit latrine. Throughout the past year, our sanitations systems technical team has been researching specific structural aspects of the latrine to ensure our latrine will provide a safer and cleaner environment for the people of Zambia.
For instance, we learned that although a rectangular pit is simpler to build, circular pits provide more structural support. The rectangular pit’s corners are more likely to deteriorate or even detach because of the direct pressure from the outside soil. However, a circular pit distributes this weight more evenly and since there are no edges, there is less stress overall.
We also learned about how many latrines are built with openings to allow for air to flow through. However, we hypothesized that this may cause latrines to collapse earlier than they should. To prevent this potential danger, we researched about effective methods to build pits. Some engineers recommend two pits to remove some of the strain on only using one pit, others advocate for the circular pit as a method to prevent early collapsing, and many recommend learning more about the soil in Zambia and how it would interact with the pit.
We went to several labs to learn more about the soil composition. This is important because we must understand the ratios of the water, sand and dirt mixture that is used for the pit and how it compares with this soil composition. Furthermore, we also learned how to implement the concrete slab on top of the pit. This research required a great understanding of torque, tensile stress and strain, as well as weight distribution.
Moreover, we also learned about the structure of the latrine itself. We plan to implement a latrine system that provides a handrail because this makes the latine more accessible to pregnant mothers who are visiting the clinic. As another latine improvement, we specifically plan to use a ventilated improved pit latrine because this latrine system improves cleanliness and also helps to eliminate pests and flies. We plan to have tippy taps outside of the latine system so that the people of Zambia will have more access to hand washing stations and cleaner sanitation methods. To remove flies, we plan to build a door for the latrine and leave it shut most of the time to eliminate the chance of flies surrounding the bathroom area. We also plan to implement a PVC pipe that will stretch from above the roof of the latrine to the pit. This pipe will effectively ventilate the pipe and create airflow. The pipe will also have a fly catcher inside of it so that if any flies get stuck in the pit, they will be attracted to the light from the pipe and then get caught in the catcher. This measure will minimize insects and improve sanitations standards for the people of Zambia. We are very excited about this project and the positive impact it will have on the Zambian community.