Building a one liter per second water treatment plant

By Andrew Kim

The AguaClara team has recently developed its latest innovation: a one liter per second water treatment plant. This small system can convert one liter (about ¼ gallon) of dirty, river water into clean, drinking water in a single second without the use of electricity. A one liter per second plant could potentially serve a village of about 40-50 homes in Honduras, a place where safe drinking water is scarce.

In Cuatro Comunidades, a small town with about 350 homes, an AguaClara plant was built in 2009 to create safe drinking water at a rate of six liters per second. The AguaClara plant, and the clean water that comes along with it, is a source of pride for the people of Cuatro Comunidades. In fact, many people who have moved out of Cuatro Comunidades have since moved back due to the improved water quality in the area. The increased population drives a need for an expansion of the AguaClara plant, which poses a perfect opportunity for the implementation of a one liter per second plant.

The AguaClara team built its first one liter per second plant in the summer of 2016. I spent many hours in the AguaClara lab that summer. Although I myself wasn’t working on the project, I was able to see the progress being made and the challenges faced by my teammates during construction and testing of the plant. Witnessing the creation of the one liter per second plant, which ended up performing as well as we had hoped upon testing in the lab, made me a firm believer in the potential applications of this technology.

It’s because of my faith in the plant that I volunteered to assemble the one liter per second plant in Honduras. In the months prior to arriving, we shipped various parts of the plant that we tested in the lab to Honduras. Some parts of the plant couldn’t be shipped and would instead have to be built in Honduras. But the idea was to completely assemble the one liter per second plant within three days of staying in Cuatro Comunidades. If we succeeded, the town could immediately have increased accessibility to safe drinking water.

The team at Cuatro Comunidades consisted of 6 Cornell engineers with varying degrees of experience, as well as the local Hondurans who were in charge of maintaining the existing AguaClara plant. Upon arriving, we saw familiar parts of the one liter per second plant that we had previously built and shipped. Alongside those parts were many brand new pieces of PVC piping, disheveled plastic tubings, and scattered joints and connections. Within three days, these materials were to be transformed into crucial parts of the one liter per second plant, such as the slow mixing chamber and reliable chemical delivery system.

AguaClara drinking water treatment plants, whether they are one liter per second or 100 liters per second, are exclusively gravity-powered. The way water flows through our plants promotes the removal of dirt and other particles. This means that with the addition of only a few chemicals, AguaClara plants produce clean water without using a single pump or watt of electricity. However, this also means that when we design our plants, we have to consider the physics and hydraulics within every single step of the treatment process. That is, when we were constructing the one liter per second plant in Cuatro Comunidades, we had to be absolutely sure that all of our heights, lengths, and angles were correct.

I had no experience with building a one liter per second plant, and neither did most of my peers who were with me at Cuatro Comunidades. Upon arriving, I expected that I would simply do what I was told. But when it came time to build, it became immediately apparent that there would be no one there with all the answers. At Cuatro Comunidades, we had to apply all of the knowledge and information we learned from our classes at Cornell. And if we didn’t have any idea of what we were doing, then people wouldn’t have safe drinking water.

And there were plenty of times when I didn’t know what I was doing. There were times where I didn’t know why the height of a pipe needed to be a certain length. But my team members did. There were times where my team members didn’t know why a piece of tubing had to be long and straight rather than short and curved. But I did. Working together was absolutely crucial since my team members and I were able to talk through all of the steps we were taking, triple check our measurements, and check each other’s sanity. Engineering is not an easy subject, but when we’re confident in our designs and calculations, taking that first step becomes easier.

The one liter per second plant didn’t solely rely on the knowledge of Cornell engineers. The wealth of knowledge provided by the local Hondurans was absolutely critical. They may not have had formal engineering training, but the Hondurans carried a wealth of practical knowledge that you can’t learn in a classroom. Not only that, the Hondurans and surrounding community in Cuatro Comunidades all shared a genuine enthusiasm and interest in the work we were doing. One of the Hondurans, Jorge, a 64-year-old man, was present throughout the process and could not be more passionate about providing clean water to his community. He taught us the optimal ways to sandpaper the connections, saw the PVC pipes, and hammer the pieces in place. Sure, we may have been just fine on our own. But Jorge showed us so many tips and tricks during the building process – methods he called the “Honduran way” – that ended up bringing the team closer together. Although I had a limited vocabulary in Spanish and struggled to communicate to the Hondurans the problems I faced, the Cornell engineers and Hondurans both ultimately taught each other a lot by showing rather than telling.

At the end of the day, through the spirited teamwork from both the Cornell engineers and Hondurans, we figured it out. The one liter per second drinking water treatment plant slowly came together to form a physical, tangible, breathing system. There were many times that we didn’t think it would all come together smoothly. There were moments when we ran out of the PVC piping, or instances when we didn’t have required connections of the right size. But we had to solve the problems that were in front of us with what we had. And in the end, water flowed through our plant and ended up cleaner than it was coming in. We figured it out.

And that’s the thing about engineers. Ultimately, we’re problem solvers. We study the math and science that goes behind a design. But simply learning theory and studying for exams doesn’t make me feel like an engineer. We start to apply that knowledge by building those designs. But simply building something, even if it means actually getting my hands dirty, cut, and bruised, still isn’t quite enough to make me feel like an engineer. No, what really made me feel like an engineer when building the one liter per second plant was communicating the problems we encountered, working together to solve them, and finding the most practical solution with limited resources. Solving problems like these is the essence of engineering, and we’re not afraid to tackle the big challenges ahead – namely, people around the globe don’t have access to safe drinking water. And we will always be innovative, empathetic, and determined when working towards that solution.