Flagstaff, Arizona On-Call Engineering and Energy Efficiency Study
On-Call Engineering Services, Reclaimed Water Plant Energy Efficiency Study, Flagstaff Water System Energy Audit, Turbo Blower Analysis, Barscreen Replacement Evaluation and Design, Biogas Piping Replacement Evaluation and Design
Tata & Howard was selected to provide on-call engineering services for water, wastewater, and energy related projects for the City of Flagstaff, Arizona. Working with VEE, several options for replacement of the blowers were evaluated and presented to the City in a report. The report recommended the installation of appropriately sized turbo blowers and upgrading the controls logic to automate dissolved oxygen controls.
The City has been experiencing long term maintenance issues with the existing biogas piping at the Wildcat WWRF. Currently the piping to the co-generator is not providing an adequate supply of gas from the digesters which, if operating, could save the City approximately $200,000 in annual power costs. The goals of this project are the restoration of the ability to run the generator on biogas, utilize the heat generated by the sludge digestion process to further reduce energy costs, reduce maintenance time to operate the biogas system, and have a positive impact on the environment, since methane is one of the most potent greenhouse gases and it is currently discharged to the atmosphere.
We are also assisting the City with the evaluation of replacing the existing barscreens at the Wildcat WWRF. The project includes the evaluation of different barscreens, design, preparation of procurement documents, solicitation of quotes, and construction administration services.
In addition, Tata & Howard conducted an energy efficiency study on the aeration blowers and pumps at of the two treatment plants. The testing showed that modifications to these systems have the potential to save the City approximately $250,000 in annual electrical costs and $445,000 in APS rebate funds for the modifications. Pumping systems had efficiencies as low as 20%. Pumps and blowers were oversized to meet peak and future demands but not efficient at low flows or off peak flows. Energy usage per million gallons treated of 2,170 KWH/MG with cogeneration and 2,804 KWH/MG at the Rio plant, with national average usage of 1,750 KWH/MG.