Pasteurization Process Generates Energy and Water
A California company is pioneering pasteurization as a third-stage wastewater treatment.
Pasteurization Technology Group (PTG) has patented a two-for-one process that heats wastewater to kill pathogens as well as generates lower cost power for industrial and municipal treatment plants.
The PTG system combines eco-friendly wastewater disinfection with renewable energy generation. The patented system runs on natural gas or biogas and heats wastewater to 74-80°C, killing microorganisms and pathogens.
The wastewater treatment system is designed to recycle heat, making it extremely energy efficient. Water is treated to a high standard making it available for reuse.
“The system recycles heat over and over,” said Tim Kingsbury, chief operating and chief financial operator of PTG. “We estimate the heat generated is reused 40-50 times. That is what makes the system so effective and makes it pay for itself. You can disinfect wastewater cheaply while generating low-cost electricity and saving money.”
According to Kingsbury, the PTG system has been shown to cut energy costs by half while saving up to 75 percent of the cost of wastewater disinfection. “It is a chemical-free, non-toxic way of disinfecting water, which is a real alternative to other tertiary treatments such as UV, which is energy intensive, and chlorine, which can leave residual traces in water,” he added.
The PTG system has been installed in a large-scale pilot project at the City of Ventura in a disinfection plant processing 1.9 megaliters per day. The results suggest a full-sized PTG system could generate enough electricity to power the whole plant at half the current cost of $900,000 per year. Using pasteurization would also save the city $250,000 a year on chemical costs.
Another pilot project has taken place in the city of Melbourne, Australia, where the pasteurization process has been found effective against giardia and cryptosporidium. After 15 seconds at 55°C, researchers reported a complete kill of both pathogens.
|PTG installation at a craft brewery in Los Angeles, Calif.|
In 2014 the first full-size PTG system was installed at Graton, Calif. At Golden Road, the largest craft brewery in Los Angeles, a PTG B-200 system was installed, generating 200 kWh of electricity to supply 90 percent of the needs of the plant. Electricity costs have been reduced by 60 percent, while boiler costs have been reduced by 80 percent. The savings will add up to more than $9 million over 20 years, helping the brewery to become energy neutral.
“Becoming energy neutral is becoming a goal for many industries and utilities around the world, which is one of the reasons we believe there is great potential for this technology,” Kingsbury said. “Pasteurization is a clean technology that treats wastewater to a high standard, which means it can be reused and recycled - for agricultural uses for example.”
In the future, Kingsbury said, the company is looking to expand into other markets, to find new industrial partners and attract investors. “Pilot projects are also currently taking place into using this technology as part of the drinking water treatment process.”
Paul O’Callaghan, founder and CEO of BlueTech Research, said, “Wastewater processing is very energy intensive so there is a great deal of potential for innovations which target the water energy nexus.”
O’Callaghan added that in the right circumstances PTG can substantially cut energy costs as well as provide an effective low-cost alternative to other forms of third-stage wastewater treatment. “As populations increase, BlueTech predicts clean tech systems such as this will become increasingly important as a way to preserve and protect existing resources.”