PARC Cuts Energy Waste in Waste Water

PARC has parlayed its expertise in printing to develop a less energy-intensive method for treating wastewater.

Municipal water utilities rarely adopt new technology, but a PARC-led project suggests that energy-saving innovations could fuel interest in water technologies.

The research company of Xerox this week said it received a $1 million grant to test a novel process that relies on specially shaped plastic disks to separate solids in wastewater. The company expects it can save money on energy and produce electricity in an anaerobic digester from the separated solids.

The grant will be used to install a shipping container in Sunnyvale, California filled with stacks of these disks and test its cost and performance for a year. If it performs well at the planned 10-million-gallons-per-day rate, the system could be scaled up by adding more modules, said Mark Stephenson, manager of PARC’s water lab.

Rather than use filters or a centrifuge to remove solids from wastewater, PARC’s Hydrodynamic Separation technology relies on channels with a specific width and depth. As the water flows down the channels, a combination of sheer and drag forces separate suspended solids with high organic content.

As the water cycles through the channels, they split into two streams, one with a higher density of solids and a cleaner stream, which can be treated further with traditional methods, Stephenson said. “The particles get entrained to the side of the channel, but not up against the wall. We get them to move in an orderly fashion,” he said.

If the test results are promising, PARC intends to license the technology to a water treatment company such as Veolia or Siemens.

PARC has a number of research efforts related to energy and water that are spun off from research in its core printer and copier business. This water filtration system stemmed from the company’s know-how in manipulating toner powder particles for laser printers, Stephenson said.

The grant is funded by the California Energy Commission, a clear reminder of how closely related water and energy are. It’s estimated that three percent of California’s energy is consumed in wastewater treatment.

The PARC system could derive some value from the waste as well. Solids could be put into an anaerobic digester, which will produce methane as it decomposes. The captured biogas, which contains methane, is then burned to make electricity, a process done in some wastewater treatment plants or farms.

PARC says the water separation technology can help save energy in other tasks, such as dewatering algae grown for biofuels or feed. A water filtration unit could also be mobile and be used during heavy rain storms when wastewater plants are inundated and can’t treat water before it reaches rivers and other water ways.