Forty-eight submersible mixers & 16 axial flow pumps are achieving complete mixing and nitrate recycling in the new activated sludge process
At the newly expanded 30-million-gal-per-day (mgd) wastewater treatment facility in American Fork, Utah, Landia completed a successful pump and mixer retrofit that transformed eight existing oxidation ditches into new high-rate activated sludge bioreactors with biological nutrient removal, solids dewatering and ultraviolet disinfection.
A total of 48 Landia submersible mixers and 16 Landia axial flow pumps are achieving complete mixing and nitrate recycling in a new activated sludge process at the site run by the Timpanogos Special Service District, close to Utah Lake, which serves 10 cities in the region.
Working in conjunction with Utah and Idaho engineering firm Bowen Collins & Associates Inc. to select long-lasting equipment that would give optimum performance, mixers from Landia now mix the sludge in the anaerobic and anoxic tanks, whilst internal Landia Recycle Pumps send nitrified mixed liquor from the aeration basin onto the anoxic tanks.
Operating at low propeller speed, each Landia mixer is equipped with large surface area propeller blades to ensure gentle treatment of the activated sludge.
The axial flow pumps operate on variable frequency drives, by which each pump’s flow rate is optimized for the required nitrate recycle rate.
“The move to bioreactors has been a learning experience for us, with a great deal of hard work put in to achieve the required mixing and recirculation," said Ed Yates, maintenance coordinator for Timpanogos Special Service District. "Landia’s pumps and mixers are performing well and the support we’ve been given by the company to help get the equipment up and running to our satisfaction has been exemplary.”
The $77 million project, which also features a new headworks and influent pump station, has increased the capacity of the treatment plant from 18.3 mgd to 30 mgd.