Imagine waking up and opening the tap to muddy water. According to the World Health Organization, that is the predicament that 1.8 billion people worldwide find themselves in. Often water treatment plants are expensive and require too much energy to run. A team at Cornell hopes to change that. Pristine, crystal clear water is a luxury, AguaClara hopes to make it a right.
“From a very broad perspective, we want to deliver drinking water and wastewater treatment to communities around the world, mainly in rural settings. We do this by developing gravity powered designs that can be transferred to communities anywhere,” said Zoe Maisel ’18, team lead.
The team’s treatment plants mirror traditional systems. Chemicals known as coagulants are first added to the water to force suspended particles to clump together. These clumps are then made to collide, forming “flocs,” as the water passes through a series of sharp turns. These heavy “flocs” then settle to the bottom of a sedimentation tank. Finally, the water is forced to pass through a series of filters and is lightly treated with chlorine to remove any remaining contaminants.
The team currently has 14 plants in Honduras and two water towers in India. Though the technology in both countries remains the same, the team tweaks their design to cater to the different sources of water: groundwater in India and streamwater in Honduras.
“In Honduras, we have a really good working relationship with an NGO and we do research here and then basically, send off our designs so that they can build them. They then provide us with feedback, tell us what they need, what needs to be improved,” Maisel said. “The good thing about it is that it can be pretty much implemented anywhere, obviously with some changes but the basic design of a gravity powered treatment plant is universal.”
The team consists of 19 subteams, most of which research different technologies that can be added to the plants. After modifications have been thoroughly tested, they are added to the base design.
“We have a couple of research teams that work on the main plant. We have a filtration research team, we do some high rate sedimentation work and we have a couple of wastewater teams that are doing most of the ground-breaking work on how to design our first low energy waste water treatment solutions,” said Natalie Mottl ’18, team lead.
The team’s wastewater treatment plants are based on anaerobic digestion, a well-established technology. The process involves adding microbes that are capable of breaking down biodegradable material in the absence of oxygen to the water. According to Maisel, the main component of such plants, upflow anaerobic sludge blanket systems, require high amounts of concrete and large pieces of land to build, often making maintenance difficult. Thus, another one of the team’s key goals is to create modular systems that can be made in Honduras and shipped to small communities.
With numerous water filtering systems available in the market, the question of how AguaClara differentiates itself from its competitors is a natural one. According to Mottl, a serious issue with existing systems is the overreliance that communities have on their producers. Indeed, many commercial systems require specific parts or energy inputs that may not always be at hand in rural communities.
“They can be appealing to communities because they seem to be a quick fix and something that other countries will help subsidize and provide grants for. I think that this type of plant is one of our main competitors and we try to beat that system by focussing on only locally sourced materials. We focus mainly on concrete and PVC, which can be expensive to put down especially because the former is very labor intensive but you can get it in any part of Honduras,” Mottl said.
“All of our designs are open-source, so anyone can access them, anywhere. That’s really important for us because in other models where there is patented information, it makes it really difficult for the community to have ownership,” Maisel added.
Because of the different needs of communities, AguaClara’s base design is often tweaked by on-sight engineers. Specifically, plants treat water at different rates depending on the size of the community and their conventional water needs.
“We have a plant in Tamara, Honduras and we talked to the plant operators, who work there 24/7 and have to log in information every hour. They told us about the problems they were experiencing and just hearing that they actually knew about the technology used in the plant was inspiring. They’re not civil or environmental engineers but they have learned about the technology because they work with it everyday and they are proud to do so,” Maisel said. “I think that is one of the things that shows us that it is working well because people want to work with the plant and they treat it as a community responsibility. It’s a revered job because it’s so socially impactful.”
“An interesting insight I got from the trip was that until people really have a switch in mindset, they really believe that this is the norm, it’s like a test, almost a rite of passage to drink dirty water. People can initially be against having a water treatment plant because they think it’s been like this forever so there’s definitely a social dynamic that is hard to see from the United States,” Mottl added.
In line with their vision to build more modular systems, the team is working on a one litre per second plant that aims to serve smaller communities of 300 to 400 people that often lack the capital to invest in large treatment plants.
“Trying to provide clean drinking water for rural communities was the reason AguaClara was started, it’s just that we didn’t have a good answer until now. So we were working with mid-sized communities but a 1 litre per second plant can serve 300 – 400 people, that’s really what we were trying to do to begin with,” Mottl said.
The team also hopes to diversify into designing more wastewater treatment plants. As opposed to the primarily physical processes used to treat drinking water, wastewater treatment places a higher emphasis on biological and chemical treatments. Consequently, Mottl believes that the team will have to conduct more research and experiment with plant designs before they can be passed onto communities.
“Applications of naturally constructed systems are more a subject of waste-water research. For waste-water research, there is more place to move around in because there are many different parts to it. You have things like trickling filters and constructed wetlands, those all pretty much use natural materials like rocks or wood chips and we may look into that later on,” Maisel said.