Jeremy Guest leads team striving to turn wastewater into drinking water
It may be something we don’t like to think about -- our drinking water taken directly from water used to flush waste from our homes, but as we approach an era where water is an ever-increasing commodity, for Jeremy Guest, Assistant Professor of Civil and Environmental Engineering at the University of Illinois, that’s the future he’s advocating.
“In technologically advanced countries like the United States, we’ve often looked at drinking water and wastewater as two distinct utilities,” Guest said. “Drinking water pulls water from the environment, treating it to an adequate quality and providing it to the population. The wastewater utility, on the other hand, mitigates the impacts of what leaves society before it gets back to the environment.”
That mindset has existed in developing countries since the onset of indoor plumbing. It is that paradigm that Guest and others are trying to change as a part of the solution for the 2.5 billion people or 1/3 of the global population who lack proper sanitation.
As Guest points out, however, the problem of finding clean drinking water is not just a developing world problem any longer as climate change and urban sprawl are at least partially responsible for an exponential increase in drought and floods across the planet.
Instead of looking at water on a linear scale in which it is taken from the natural environment, consumed, and sent away from the population, Guest and his colleagues have been working on ways in which to “close the loop,” to treat wastewater, procure the useful by-products of waste, and reintroduce the water safely back into the system. This engineered water cycle provides not only a source for water, which is often cleaner than what was collected from the environment, but also for nutrients and energy. In addition to proving the method is safe, the challenge is to develop the technology to a point that it is financially viable and energy positive to actually effect change.
Since a high percentage of people who lack access to safe drinking water and sanitation reside in Africa, much of the focus for Guest and other members of the Safe Global Water Institute (SGWI), which is housed at the University of Illinois, have been on that continent. Forming partnerships with non-governmental agencies and universities in countries like Kenya, Uganda and Tanzania, they have been not only testing, but also educating local partners on the potential benefits of this system. For change to come to these low-income communities, however, the biggest incentive for people is not always its sanitary benefits, but also the potential for wastewater to serve as a renewable economic resource.
For starters, through anaerobic membrane reactors, Guest’s team is taking organic carbon from human waste and turning it into methane – a gas that can be used for heating or cooking – while also providing nutrient rich, high quality water which can be applied to crops to increase yield.
“Right now, there aren’t tangible incentives to motivate changes to sanitation in developing communities,” Guest said. “So we are focusing on leveraging waste to produce energy and recover nutrients for agriculture. Any technologies we develop, we make sure we recover these resources in a way that is safe for the population. Altogether, this creates financial incentives to properly manage bodily waste.”
While the economic piece will likely be what drives developing communities to adopt these practices, the real incentive for those working on the project is to end the cycle of extreme poverty and decrease the likelihood that children will suffer from diarrheal disease and stunting. The United Nations’ Millennium Development Goal to halve the percentage of people without access to improved sanitation by 2015 fell short, underscoring the need for new approaches to the development and deployment of sanitation solutions.
“The magnitude of the problem is tremendous,” Guest said. “Lack of sanitation continues to pollute local water resources, which then undercuts the ability for communities to develop and pull themselves out of poverty. Unsafe water and fecal pollution have serious health consequences, with children under five years old – one of the most impacted populations – susceptible to death as well as stunting and other conditions that can have long-term cognitive and health implications.”
In some ways the lack of a sanitation system in the developing world will make it easier to adopt the “closed loop” method.
“By focusing on the developing community context as we develop novel technologies that close the loop on resources and lets us provide water and sanitation more sustainably, we have the advantage of not being locked into the centralized (old) infrastructure,” Guest said. “So we can really think outside the box and innovate in ways that removes a lot of constraints that traditionally limit our ability to develop novel technologies.”
While it may be more challenging to make significant changes in developing countries, Guest believes change will come in more developed nations by also proving the economic viability. The goal is to create a system that makes sense economically and actually has a net gain in energy, which is distinct from current technologies which use a lot of energy and chemicals to break down components of wastewater and send it back into the environment with no added benefits.
“In the U.S., one of our main objectives is to transition this resource intensive waste management strategy to one that is energy positive, recovering the nutrients in a way that we are actually increasing the energetic content of the waste so that the treatment system can pay for itself.” Guest reiterated. “We are focused on completely redesigning our wastewater treatment plants to produce methane and other useful gases while also recovering the nitrogen and phosphorus for use on crops.”
In addition to using anaerobic technologies, Guest’s team is using microalgae to not only produce a biodiesel stock, but also as a precursor for ethanol and methane production. In order to change the mindset, they are shifting from referring to the places where this is happening from “wastewater treatment plants” to “water resource recover facilities.”
Through centers like SGWI and the Soybean Innovation Lab, Illinois has taken on great leadership in providing these types of solutions. In addition to partnerships with top universities in East Africa (like the University of Ghana) and King Abdullah University of Science and Technology, Illinois teams are collaborating with Western universities from the likes of Scotland, the Netherlands and Switzerland and governmental entities such as the U.S. Agency for International Development. Those collaborations aren’t just coming from the College of Engineering either, but also from top researchers in natural sciences, crop sciences, and business.
“Thanks to our collaboration with the College of Business, for instance, we have been able to work at the intersection between technology, innovation and subsistence marketplaces,” Guest said. “It gives us a lens, but also a skillset to really innovate in novel ways that have a global impact.”
Through modeling, they are able to design systems that will be able to out compete with other technologies. In linking models with life cycle assessments and costs to prove a broader economic impact, they hope to be able to influence decision-making.
“Now is absolutely the time to act,” Guest said. “This transition is slowly starting to happen and regulation and investment is starting to follow. In the U.S. alone, we’re looking at massive needs on the order of hundreds of billions of dollars for water and sanitation infrastructure. As we think about innovative technologies to try to recover these resources and close water cycles, one of the critical challenges is that we have been locked into trillions of dollars of investment in the current centralized infrastructure. However, as we become increasingly aware of the importance of recycling these resources, of developing more resilient and adaptive approaches in water and sanitation services, it’s incredibly important to take this opportunity to invest massive amounts of financial resources into infrastructure upgrades in a way to position us to sustainably provide the services to 21st century societies.”