By Jim Montague, Contributing Editor
Just as potentially life-sustaining planets need to occupy a "Goldilocks zone" that isn't too hot or too cold for liquid water, most process applications must also run in acceptable ranges. The trick for earthly users is securing the data required for timely adjustments and optimization, which often means collecting it from difficult or historically impossible-to-reach settings that might as well be in outer space.
For instance, the Water Recovery Facility in Warren, Michigan, operates a waste-activated sludge application that sends worn-out microorganisms from its wastewater aeration facilities to be incinerated. This process combines old sludge activated by diverted primary/updated sludge, which is blended with one gallon of polymer diluted in 1,000 gallons of water.
This lets a belt press dewater the sludge down to cake that's 18-20% solids, which is best-suited for burning and scrubbing in compliance with Michigan's clean-air regulations and even approaching California-level clean-air rules.
The application can process 340 gallons per minute (gpm) of activated sludge, using 3 gpm of the polymer solution, and produce 5 to 5.5 tons of cake per hour. However, its flows must be accurately monitored and precisely maintained to avoid ineffective use of its chemicals and overuse of its power.
"Once the secondary clarifiers have settled down, our waste-activated sludge process intercepts some of the return flow, and sends it to sludge-handling storage to prepare it for incineration," says Bryan Clor, head of the wastewater treatment division for the City of Warren, just north of Detroit.