The X-500 (500,000 gpd) wastewater treatment system from the Pasteurization Technology Group (PTG) is a non-toxic process designed to replace chlorine-based or UV disinfection while generating on-site electric power. The combined heat and power system (CHP) takes the pasteurization process used in the food and beverage industry and applies it to wastewater for reuse in agriculture and other industries.

The modular component system uses biogas or natural gas to fuel a turbine that generates electricity and exhaust heat. Exhaust heat (950 degrees F) is captured and fed to an air-to-water heat exchanger that rapidly warms incoming wastewater to 180 degrees F.

Once pasteurized, the wastewater is sent to a water heat exchanger where incoming wastewater cools the disinfected water to 73 degrees F for output. In the process, incoming effluent is heated to 177 degrees F before entering the air-to-water heat exchanger. The looped system requires less than 3 percent of the energy typically needed to disinfect the wastewater. On a large scale, energy generated by the system can eliminate a plant's need for grid power and even generate excess electricity that can be sold back to the grid. The disinfected wastewater can be used for agriculture or irrigation.

Larger or smaller systems (as low as 100,000 gpd) can be configured according to need, with potential to treat more than 100 mgd. The system, for new plant construction or retrofits, works with any size of wastewater solids. "The unique thing about heat is our system doesn't really care about solids," says Greg Ryan, PTG co-founder and CEO. "We can actually disinfect secondary effluent. We don't need it to be tertiary, filtered."

PTG is now working with the Ventura (Calif.) Water Reclamation Facility to transition it from a chlorine-based process to the new technology. The goal is to discontinue the handling of chlorine, reduce costs and support expansion of the water reuse program to help preserve the local estuary and coastline.

Now in the optimization phase, the reuse system is estimated to generate enough energy to power itself and the entire facility for an annual savings of $450,000 per year. Eliminating chlorine will save $250,000 more per year. 510/357-0562; www.pastechgroup.com