Casa Grande Water Reclamation and Pretreatment Facility

Casa Grande Water Reclamation and Pretreatment Facility



Engineering Excellence Special Merit Award - 1996

Carollo Engineers completed evaluation, upgrade and expansion of the Casa Grande Water Reclamation and Pretreatment Facility from 2.6 mgd to 4 mgd. After evaluating the Casa Grande plant, Carollo refurbished the existing plant for pretreatment and constructed a new oxidation ditch treatment plant. The refurbished pretreatment facility has generated renewed interest in Casa Grande for some new industries looking to relocate in Arizona. The refurbishment was prompted by the proposed expansion of Ross Products, a division of Abbott Laboratories, a manufacturer of a powder infant formula product. This expansion would create approximately 100 new jobs in the City. One of the major stumbling blocks to Ross’ expansion, though, was limited wastewater disposal capabilities. Like most communities operating a wastewater plant, Casa Grande has an industrial pretreatment program regulating the discharges that industries are allowed to send to the treatment plant. By converting the Casa Grande’s treatment plant into a facility that would treat Ross’ waste, their obstacle was eliminated and also their own plant wastewater system because now they could use the new City Water Reclamation Facility.

Schedules for all projects were adjusted to coincide with each other. The new plants are up and running and meeting all treatment parameters. The $11 million water reclamation plant upgrade and expansion project includes full tertiary treatment, capable of producing effluent with a total nitrogen concentration meeting drinking water standards and unrestricted reuse. Effluent is used for both golf course and agricultural irrigation. The new water reclamation facility includes preliminary screening, influent pumping, grit removal, secondary treatment, tertiary filtration, and disinfection. Solids treatment is by aerobic digestion and thickening for liquid hauling to agricultural injection sites. Carollo provided cost-effective wastewater service to the community, reused the existing plant and provided a unique economic development tool for the community.