A New Way To Clean Up Dirty Water, And Generate Power In The Process

The wastewater treatment plant of the future won’t gobble up chemicals and electricity in order spit out clean water; it will generate clean water and electricity at the same time.

A New Way To Clean Up Dirty Water, And Generate Power In The Process
Ilya Andriyanov/Shutterstock

Today’s wastewater treatment plants often generate water that’s clean enough to drink. But the treatment process is power-intensive–wastewater treatment plants are often the biggest energy-suckers found in cities–and it’s dirty, too.


Chlorine disinfection technology kills bacteria using carcinogenic chemicals, while ultraviolet disinfection uses “ungodly amounts of energy and electricity,” according to Greg Ryan, cofounder and CEO of Pasteurization Technology Group (PTG).

PTG, a San Leandro, Calif.-based startup, just raised $1 million from EIC Ventures (the company has raised a little under $2 million in total) for an alternative: a treatment plant that pasteurizes water–raising its temperature to 180 degrees Fahrenheit–using waste heat from an electricity generator that runs on biogas produced by a sewage digester (which breaks down all the solid sewage found in the wastewater it’s then pastuerizing). It’s a self-contained system that’s cheaper to run than traditional wastewater treatment plants, largely because the built-in electricity generator keeps energy costs down.

“We’ve shown that we can make a city money because we can take biogas and generate renewable energy on-site. No other technology comes remotely close,” says Ryan.

The system has, of course, attracted interest from municipalities interested in saving money. After building four pilot plants, PTG is now working on two full-scale projects in California. PTG also has a food and beverage client in the Rockies. The company has seen interest from the oil and gas industry in the central U.S. as well.

PTG’s system is also ideal for our dirty water issue of the moment: cleaning after the fracking process. Because it has a small footprint, can be containerized, and eliminates the need for gas companies to truck their dirty water to outside wastewater treatment plants (or just dump the dirty water into local water sources, as sometimes happens), Ryan says the tech is perfect for on-site fracking water remediation.

Still, municipalities will likely be some of PTG’s biggest customers. At a time when no city wants to spend extra money (or waste precious water resources), this wastewater treatment system is an ideal way to conserve power and clean up dirty water well enough that it can reused for agricultural purposes.

About the author

Ariel Schwartz is a Senior Editor at Co.Exist. She has contributed to SF Weekly, Popular Science, Inhabitat, Greenbiz, NBC Bay Area, GOOD Magazine and more.