Design-Build Effluent Re-Use System, Fort Huachuca, AZ
Completion Date: 11/30/2009
Award Amount: $9,305,000
Customer/Owner Name: U.S. Army Corps of Engineers
Point of Contact: Michael Brown, Contracting Officer
Description: The Effluent Re-use project that CJW constructed consists of two (2) major components.
The first is the transfer of wastewater from the Huachuca Cities existing plant to the WWTP located at the Fort. The construction includes the installation of approximately 38,000 feet of up to 10” Diameter PVC forcemain and Electrical conduit with a combined quantity of 60 Air Relief and Blow Off assemblies and three (3) wetwell type, duplex submersible pump stations with back up emergency generators.
The project commences at the site of the proposed holding pond at Huachuca City and follows the military reservation boundary following the existing desert terrain maintaining a minimum of 3 Ft of cover. The piping crosses State Route 90 and ties into the Fort Huachuca’s existing influent sewer upstream of the existing Headworks facility. The Road crossing construction consists of a 24” HDPE casing pipe installed by the jack and bore method containing the forcemain along with a conduits which house the fiber optic lines.
The second major component of the Effluent Re-use Project is the construction of Equalization Basins and Pretreatment Facilities at the site of the Fort Huachuca Waste Water Treatment Plant. The basins have been constructed to contain a total volume of 3.0 million gallons. They include two identical, interconnected cells with a PVC liner basin screened backfill and shotcreted slopes. Both cells have a direct drive mixer and floating aerators capable of continuously and selectively mixing and/or aerating the basin(s). Operations of the pump stations and the equalization basins are terminated and controlled at Ft Huachuca’s existing waste water treatment facility. Provisions have been made to monitor and control the flows from Huachuca City holding ponds which are to be constructed under a separate contract.
Challenges: CJW has been able to provide valued engineering and sustainable design multiple times under this contract by performing careful inspections of the existing site, often utilizing specialty contractors or consultants to determine the best use of government funds, most desirable product in terms of longevity and aesthetics and timeliness. This project included portions of the existing asphalt which were structurally unsound making it necessary for removal. For this project which pavement removal, the broken asphalt, concrete and existing base materials were transported to a processing facility to be re-used as aggregates (CMB, Class 2 base, etc.) on future projects. Additionally, recycled aggregate base is/was used where possible.