1. What is EcoMachine?  It is a machine that reduces water consumption in the Aiken Center by treating sewage exiting the building and then returning it as grey water to flush toilets. What you are looking is actually three EcoMachines! You see plants in there because they form mini ecosystems that cycle the energy and nutrients in the sewage water.

2. Beginning Steps of the EcoMachine (Step #1)  It all starts when a sink, a toilet, or a shower is used in the Rubenstein Building. This water flows down into a 3,000 gallon septic tank. In the septic tank, heavier solids sink to the bottom while fats and lighter things, float to the top. The water on the bottom and the top is blocked off from going further and the water from the middle is allowed to move on to the next step.

3. Closed Aquatic Cells (Step #2)  Untreated water flows from distributing valve into 3 large white closed aquatic cells. These each are holding approximately 800 gallons. This untreated water is being circulated in the tanks from an air diffuser. Water is being pulled down and then re-circulated back to the top of the tank with an airlift circulation pipe. These bubbles being pumped in are full of oxygen which helps with scrubbing odors from the gas and act as a catalyst for the nitrate process. It is important that this is a closed aerobic system because otherwise the stench of the fluids would escape. The air in the top of the tank, which is about 1”, is being diffused into the bio-filters, where plants and other organic materials break down and absorb the smell. Once this water is oxygenated, it will then move to three aerobic tanks.

4. Bio-filters  What happens to all of the smelly gases produced by the human waste processed by the Eco-Machine? We can’t vent them inside, as nobody would ever want to enter the Aiken Center, and we can’t vent them outside, as passing students would have to smell them. The solution is a series of Bio-Filters. Bio-Filters clean the gas by allowing it to rise through a combination of limestone, mulch, and compost, releasing the remaining air into the machine room. The Bio-Filters are so effective that you will never smell a thing.

5. Open Aerobic System (Step #3)  After the closed aerobic tanks, the water moves to three 200 gallon open aerobic tanks. These tanks are like the closed aerobic tanks, but they are open at the top and contain vegetation on the top. The vegetation is held up by a fiberglass plant rack. A diverse amount of vegetation provides a large surface area for microbial growth. The plants also perform nutrient uptake and can process some of the nitrogen in the water. It is home to a variety of aquatic micro-organisms, invertebrates, and wetland plants that work together to break down pollutants and use the nutrients in our sewage for their own benefit. When the water leaves here and enter the wetland, it is relatively clear.

6. Wetlands (Step #4)  Each treatment train have one vertical flow constructed wetland. The water is sent to a wetland head box that sits on top of four and half feet of gravel. The water is dispersed through the head and into the gravel where it makes it's though out the wetland box. After reaching the bottom, the water disperses and eventually flows upward through the gravel substrate and root zones of the wetland plants. Once it reaches the other side of the box it is sent to the wetland sump station. Fun Fact: This water is clean enough to swim in!

7. Sand Filter  After the wastewater has traversed most of the Eco-Machine, the majority of toxins have been removed. However, there are still particulates and a few toxins that must be removed before the water can be re-circulated. Sand has the ability to filter out many of these remaining toxins and particulates, so near the end of the Eco-Machine cycle, the water is pushed through special Sand Filters. These allow the disinfection of the water to proceed quickly and efficiently.

8. UV Disinfection  There is still one final step before the water can be re-circulated. Some bacteria, fungi, viruses, and pathogens have the ability to slip through all of the systems of the Eco-Machine. However, Ultraviolet Light has the ability to kill these remaining pathogens, so the final step of the disinfection process is to circulate the water through a UV treatment unit, which bombards the flowing water with short-wave, Ultraviolet Light, making the water safe for reuse.