Improving water and energy performance in Arizona

The SWWTP is an 800,000 gpd (0.8 MGD) wastewater treatment plant (WWTP) that serves the majority of the 7,400 citizens of Wickenburg, AZ. The original 2003 infrastructure had experienced major degradation and loss of full service and redundancy. To meet the town’s goals of sustainable compliance, available capital budget, desired schedule, resilient performance, redundancy and reduction in long-term operations and maintenance (O&M) costs, a series of projects was scoped to prioritize improvements and upgrades to the facility.

The SWWTP is an 800,000 gpd (0.8 MGD) wastewater treatment plant (WWTP) that serves the majority of the 7,400 citizens of Wickenburg, AZ. The original 2003 infrastructure had experienced major degradation and loss of full service and redundancy. To meet the town’s goals of sustainable compliance, available capital budget, desired schedule, resilient performance, redundancy and reduction in long-term operations and maintenance (O&M) costs, a series of projects was scoped to prioritize improvements and upgrades to the facility.

The initial evaluation identified that the existing aeration system – which consisted of two 330,000 gallon basins with draft tubes and surface mechanical aerators – was struggling to sustain the desired dissolved oxygen (DO) concentrations and to properly monitor the DO for process control, and the structure was experiencing advanced degradation. An upgrade of the primary aeration basins was made a first priority.

GHD identified that the best alternative was to upgrade to turbo blowers with fine bubble air diffusion and advanced control, to add a redundant pump for recycled activated sludge return line to the anoxic basin, and structural rehabilitation of the aeration basins. The team developed the design and completed the permitting in February 2018, followed by the bidding period where FELIX Construction Company was selected. Construction started in September 2018 and was completed in February 2019.

The significant cost savings this project will deliver is in the reduction in long-term energy use. The high-efficiency, turbo blowers provide over 80% reduction in horsepower to operate the aeration process, and provide a true redundant system, where each blower is sized for the maximum daily demand for the rating of the facility. Another benefit is the elimination of the previous surface mechanical mixing system, which especially on windy days would sling wastewater to and beyond the perimeter of the aeration tanks. The upgrade has improved the overall air quality for the town operators and staff, as well as any occasional site visitors.

“This project demonstrates the town’s commitment to efficiency and performance in wastewater treatment. Thanks to the Town of Wickenburg for the opportunity, to Felix Construction Company, Darcor Electrical Engineers, and to the GHD team members who helped deliver this project,” said Frederick Tack, Project Manager and Wastewater Treatment & Consulting Group Manager in Phoenix.

“This project demonstrates the town’s commitment to efficiency and performance in wastewater treatment. Thanks to the Town of Wickenburg for the opportunity, to Felix Construction Company, Darcor Electrical Engineers, and to the GHD team members who helped deliver this project,” said Frederick Tack, Project Manager and Wastewater Treatment & Consulting Group Manager in Phoenix.

The upgrade has also received a 2019 Water & Wastes Digest Top Projects award from Water & Wastes Digest. These awards recognize incredible work on water and wastewater projects that improve sustainability, require multi-agency coordination, overcome unforeseen challenges and still manage to be completed on time and within the prescribed budget. Only 10 awards are given each year across the USA.

The upgrade has also received a 2019 Water & Wastes Digest Top Projects award from Water & Wastes Digest. These awards recognize incredible work on water and wastewater projects that improve sustainability, require multi-agency coordination, overcome unforeseen challenges and still manage to be completed on time and within the prescribed budget. Only 10 awards are given each year across the USA.

• Upgrade of mechanical mixing system to turbo blowers with fine bubble air diffusion and advanced control
• 80 percent reduction in horsepower needed to operate aeration process, translating to a significant reduction in long-term energy use
• Improved water and air quality for the long-term
• Added redundancy to bolster system performance and resiliency
• Reduced long-term operations and maintenance costs
• Recipient of a 2019 Water & Wastes Digest Top Projects award
• Recipient of a 2019 Water & Wastes Digest Top Projects award