SAME sustaining members on innovative water treatment projects

By Rona Aquino on Jul 30, 2012 | 1 comment

SAME Sustaining Members to the Rescue

SAME sustaining member companies CH2M Hill, MWH Constructors Inc., and Jacobs collaborate on an ongoing $720-million water treatment project using innovative design and technology to improve the quality of Pima County’s drinking water. Located in the south central region of Arizona, the county faced a water treatment issue that posed potential threats to its aquatic life and county residents.

Pima County’s Water Troubles

Back in 2012, the Arizona Department of Environmental Quality (DEQ) ruled that Pima County’s wastewater-stripping and treatment plants were releasing wastewater that contained high levels of nitrogen, which exceeded federal requirements. DEQ had set permissible limits and a deadline to meet the requirements. As a result, Pima County’s Regional Wastewater Reclamation Department (RWRD) embarked on a plan to improve the quality of its effluent. The plan includes upgrading and expanding the Ina Road water plant and replacing the outdated Roger Road wastewater stripping plant with a new water reclamation facility. Both plants discharge directly into the Santa Cruz River.

Nitrogen Diet Reduces Arizona County's Drinking Water Threat (Photo: ENR, MWH)

Innovative Techniques

• At the Roger Road plant, CH2M Hill opted to use a dissolved air flotation (DAF) system at the beginning of the process train rather than at the end, saving the county the need for four extra primary clarification tanks.
• CH2M Hill expanded on the five-stage Bardenpho nitrogen-removing process concept by incorporating step-feed and simultaneous nitrification and denitrification features, providing greater operational flexibility. This will also result in higher effluent-water quality at lower capital and life-cycle costs.

Source: Engineering News-Record

Pima County and the top-tier firms’ efforts to improve the county’s water were confronted with some surprises and hurdles. Find out more by reading Engineering News Record‘s article Nitrogen Diet Reduces Arizona County’s Drinking Water Threat.

More Water Topics on TME

The July-August issue of TME has a theme of Water Planning and Management. On its cover, the issue features an aerial view of the new Elwha Water Treatment Plant in Washington. Featured articles include Achieving the Unprecedented in New Orleans; The Largest Dam Removal Project in U.S. History; Sea Level Rise in San Francisco Bay; Extend the Life of Infrastructure; Engineering a Fresh Opportunity; and Stormwater Compliance for Military Facilities. Click the image below to read the issue now in its entirety [PDF ].