Two weeks ago, we wrote a piece on upcycling your “business,” going into the green uses some companies found for human waste. Innovation and recycling mean looking everywhere possible for solutions, and The Optimist Daily loves writing about the ones that are found… even if they come out of the toilet.
The Clackamas County Tri-City Water Resource Recovery Facility in Oregon has been repurposing human waste to produce its own energy for treating wastewater.
Resilience through renewable energy
In the summer of 2020, wildfires were burning throughout Oregon, and some were threatening the Clackamas County water treatment facility. If the fires caused the facility to lose power, it could’ve released large amounts of waste into the Willamette River, causing serious environmental damage. This was a wakeup call. The facility needed to ensure that it could stay on in emergencies. That’s when they decided to start using the facility’s own wastewater input to power the water treatment.
Since August 2021, the Clackamas facility has been partially powering itself with renewable methane, a natural byproduct from human waste.
How to turn human waste into renewable energy
Remarkably, the only actual waste left over from the Clackamas facility is garbage like broken toys, discarded home appliance parts, etc. Everything else gets repurposed in the many filters and stages of their treatment system.
One of these stages is basic mesh filtering which takes out hard garbage made from plastics and other materials. The next stage removes grit like asphalt, limestone and concrete, as well as eggshells, coffee grounds, seeds, bone fragments and other organic food waste particles. These get saved for later, so remember them.
More processes of filtration, UV treatment, and the introduction of bacteria microbes to break down waste, much like food in a human stomach, clean the water and release it into nearby rivers. Remaining biomass then moves into one of the three anaerobic digesters, which use naturally occurring microorganisms in an oxygen-free environment to further break down the remaining organic matter.
This produces concentrated methane, which is transferred to a 600 kW lean-burn co-generation engine that turns it into heat and power. But that’s not all.
Remember those grit solids that got removed? Those are also repurposed to create nutrient-rich fertilizer which is sent to farms in eastern Oregon to be used on non-food crops.
Almost every part of the wastewater that comes into the Clackamas facility finds a new purpose, allowing the facility to power itself in the event of another emergency like the 2020 wildfires. They are a shining example of becoming resilient through renewable energy while also serving their community.