Wastewater treatment plants are becoming recognized as resources for electricity, fertilizer & heat
The Chambers Creek Regional Wastewater Facility in Pierce County, Wash. represents an emerging trend in the renewable energy market: transforming waste into energy. Wastewater treatment plants (WWTPs) are increasingly recognized as community resources for electricity, fertilizer and heat, as waste to energy projects become commonplace in a sustainable economy.
Mortenson Construction is handling the expansion of the Chambers Creek Regional Wastewater Facility to increase its production of digested methane gas, which is one of the most effective and efficient ways for new or upgraded WWTPs to generate energy for surrounding communities.
The expansion adds two anaerobic digesters—for a total of five—and new digester gas-fueled steam boilers to heat the plant—thereby substantially reducing the reliance on external energy sources. The energy produced at Chambers Creek will be used to heat the plant year round and create 40 dry tons of fertilizer a week.
"We strongly believe that the transformation of waste into energy is a huge opportunity that will transform the renewable energy market and have a positive impact on communities," said Jim Yowan, vice president of Mortenson Construction. "Wastewater is a continuous source of energy that will only increase over time. Many of the technologies which are needed to transform waste to energy exist today. Now is the time to tap into this underutilized resource."
According to the Water Environment Research Foundation, wastewater contains up to 10 times the energy needed to treat it—providing a network of distributed, decentralized energy sources which are already constructed and piped.
WWTPs are currently responsible for approximately 1.5% of total U.S. energy consumption. For some municipalities, this translates to 30 to 40% of the total electricity bill. Since the need for wastewater treatment will only increase with population growth, closing the energy loop is rapidly becoming a primary focus of many municipalities.
Expansion of the Chambers Creek Regional Wastewater Facility is scheduled to be complete in the spring of 2016.