By Rick Smith, CH2M HILL Program Manager
The Spokane County Regional Water Reclamation Facility (SCRWRF) in Spokane, Washington, is an advanced, state-of-the-art, wastewater treatment plant which provides an initial 8 million gallons per day (mgd) of treatment capacity for a residential and commercial/industrial service area, with an ability to expand capacity in phases up to 24 mgd. Recognizing that every bit of energy saved by our industries adds to their bottom line and at the same time protects our environment, CH2M HILL worked in partnership with Avista Utilities and Spokane County to develop near-term and longer-term energy-saving components for the project.
The facility uses state-of-the-art membrane filtration technology, and will achieve treatment levels for nutrients that are some of the most stringent in the nation. The plant’s sustainable design allows energy recovered through digester gas production and co-generation systems to produce electricity to help run the facility. All non-process buildings are designed to meet Leadership in Energy and Environmental Design (LEED) Silver criteria. A few-energy saving design components included a compact site footprint, use of treated effluent for site irrigation and process operations, LEED Silver certification of the three main buildings, onsite production of energy (heat and electricity) for internal plant operations, and incorporation of high-efficiency post-aerobic digesters, aeration blowers, and motors.
The new facility uses waste heat from the primary screening room and routes it directly to the primary clarifiers via fiberglass-reinforced ducts for the purposes of preventing ice formation on the underside of the clarifier covers. Another innovation involves the management of digester gas at the SCRWRF, which incorporates a cogeneration system that captures biogas from the anaerobic digesters, stores it, and then transfers it to a gas conditioning/micro-turbine system that generates electricity and hot water for process and utility needs. The team has estimated that total electricity usage could be reduced by up to 2.8 million kilowatt hours per year, resulting in nearly $200,000 in energy cost savings yearly.
Because this project used design-build delivery, designers worked closely with the construction team to consider energy and life-cycle costs of the facilities and implement solutions that provided these energy and electricity savings. The Design-Build Institute of America gave the project its National Award in 2012, recognizing the team’s excellent, integrated approach to deliver design and construction services under one contract with a single point of responsibility. Spokane County’s decision to procure the project using design-build delivery ultimately saved about 15 percent in overall budget and schedule.Additionally, due to the project’s consistency in reducing both the Total Recordable Rate (TRR) to 1.83 and the Days Away Restricted Time (DART) rates to 0.00 points, well below the industry average, the project was also awarded CH2M HILL’s Excellence in Safety Program Award, one of the firm’s highest commendations.
I’m proud to share that this award-winning project has recently earned another important recognition—the Washington Industrial Energy Leaders Award for its innovative energy management. Washington Governor Chris Gregoire presented the WIEL Leadership in Innovation Utility Sponsor Award to Spokane County, CH2M HILL and Avista Utilities at an awards ceremony at the State Capital in December, and the award winners were also featured in a special session at the Fifth Annual Northwest Industrial Energy Efficiency Summit on January 16, 2013, in Portland, Oregon. The Washington Industrial Energy Leaders Award was created to identify and recognize Washington industries that demonstrate energy efficiency leadership and commitment. In particular, the Leadership in Innovation Award given to the SCRWRF project recognizes highly innovative energy projects, including emerging technologies, use of existing technologies in a new way, or a unique change to a process that saves significant energy.
It has been a pleasure working on this project and I’m looking forward to continuing to push the boundaries of what can be achieved in energy management at water and wastewater facilities as I move on to the next challenge.
Rick Smith is a program manager, senior project manager and senior mechanical engineer with CH2M HILL’s Global Water Business Group, based in Spokane, Washington. He has served as a program manager, project manager or project engineer for wastewater treatment plants, including value engineering studies. He has also led and executed engineering studies, designs, and services for industrial, municipal, commercial, and institutional projects. Smith has experience in pumping and compressor systems, incineration, materials handling, boiler systems, and control systems. Smith has participated in many of CH2M HILL’s large and complex wastewater conveyance and treatment projects in his 36 years with the firm.
This article has been republished with permission by CH2M Hill. To view the original article, visit CH2M Hill's blog here. To download the Water Design-Build Council's case study on this project, click here.