University of Vermont

Greening of Aiken Update: Eco-Machine Ramp-Up

By Matt Beam, research specialist

Aiken Center Eco-Machine
Aiken Center Eco-Machine

Many in the Rubenstein School may be wondering about the status of the Eco-MachineTM across the entryway from the solarium. For those new to the expression, "Eco-Machines" are assembled ecosystems designed to perform some sort of work. The Aiken Eco-Machine is converting wastewater into clean, safe water to recycle for toilet flushing. The wastewater is purified by growing a complex, self-designing ecosystem on the nutrients and energy in our waste — right in our front entrance! This Eco-Machine is not only a research system and a Vermont Agency of Natural Resources pilot project as the first ultraviolet sterilized water recycling plant in the state, but also a powerful statement about environmental stewardship by the Rubenstein School.

Treating our waste in such a visible way and not simply pushing it out-of-mind and down-the-drain sends a message about environmental responsibility and justice. It turns the Aiken Center into a living building, with a metabolism, that tells a story about partnering with nature for mutual benefit. It teaches about ecosystem services and how we fit into the larger picture. Investing in an Eco-Machine shows that as a community, we understand the importance of developing and refining technologies that strengthen our natural resources base while sustaining human communities. It is these ideas that I believe hold the most promise for us to adapt to a changing world and to improve our relationship with the larger environment.

 

Eco-Machine status update
Currently, we are in the commissioning and ramp-up phase of the Eco-Machine treatment and recycling system. This involves running the system and locating and fixing any problems before reusing the purified water.

Increasing amounts of wastewater have been introduced to the system in the past three months, as we have continually seeded the system with life. Seeding involves going into the field with mason jars, buckets, and turkey basters and taking water and sediment samples from diverse aquatic ecosystems. We add these samples to the Eco-Machine tanks which then self-organize to create novel ecosystems. So, by gradually increasing the amount of waste added to the system while continually inoculating with wild stock, we have been building up the communities that thrive on the waste in the water and thus increasing their capacity to consume waste in a process called "ramping-up."

During the ramp-up phase some issues have been identified and most fixed, with a few that are in the process of being resolved. For instance, we had to tweak the controller's programing logic and play with the float levels in order to get the pumps outside in the septic tanks operating reliably. Some small alterations were made to the tanks in the eco-room to optimize water flow. Additionally, building residents may have noticed a sewer smell in the building. After some investigation, the odor was found to be coming from the sewer vents on the roof and not from the Eco-Machine room itself or the manholes in the sidewalk. In order to solve this issue, we are attaching charcoal filters to the vent pipes.

Parallel to ramping-up and testing the Eco-Machine, Assistant Professor Anthony McInnis and I have set up a water quality analysis lab to support the Eco-Machine and green roof as research and education tools. Once the lab is up and running, we will begin data collection and turn on the reuse portion of the treatment system.

 

Research update
The Eco-Machine is designed as a research tool. What you see in the Eco-Machine room is not one but three nearly identical treatment systems, or “treatment trains,” each made up of three large tanks, running parallel to each other. On top of this, each train is plumbed in such a way that the sequence of treatment cells can be changed. So, there is an experiment, and research questions, built into the system already: how do the different treatment sequences compare to each other in terms of water quality, air requirements, or ease of maintenance?

Although the physical structure of each train is the same, they vary quite a bit in light-availability. As a result, the plants and microfauna that have taken hold are slightly different in each tank. Because of this, it will be best to operate all trains in the same manner for a period of at least one year to generate baseline data. These data will enable us to establish a statistical relationship among the performance of the different treatment trains. For example, we may find that over the course of the whole year, train A removes 2% more nitrogen than train C on average. Once we have these relationships described, we are free to experimentally change the trains and can attribute changes outside the baseline range of variability to experimental changes.

During this period of baseline research, we can answer some basic questions about system performance, stability, and ability of the Eco-Machine to remove a variety of substances as compared to a standard treatment plant. We can also test experimental filters for things like phosphorus removal and biological disinfection. During the baseline period we can also experiment with many bench-scale systems to cheaply identify those promising areas of research that should be tested on the larger Eco-Machine in the future.