With water supplies reaching their limits, and the difficulties and expense inherent in the construction of new storage projects, recycled water has become an environmentally and economically viable method for extending and conserving supplies. Recycled water, properly implemented, does not present a health risk and has become not only acceptable, but favored by the public.
Major projects have been constructed in many states, particularly California, Florida, and Arizona. In Colorado, fifteen projects are on-line, including Colorado Springs, Aurora and Parker. When constructed, Denver’s project will be the largest in the state (45 million gallons per day). Ultimately, the project will provide more than 15,000 acre feet of new supply, an amount equivalent to the usage of about 30,000 households. The project will provide about 23% of the projected supply needed for the growth in demand in Denver Water’s Service area for the next 30 years.
Treatment and Water Quality
The Denver project will take wastewater from the Metro Reclamation plant and treat it to a quality suitable for irrigation and industrial uses. Basic treatment processes will include coagulation, sedimentation, filtration, and disinfection with chlorine. The planned water quality will meet or exceed the current draft guidelines as set by the State of Colorado.
Project Timing and Cost
The recycled water project will be constructed in two phases. The first phase will serve users in the plant vicinity. Those users include a golf course, oil refineries, the Cherokee Plant of Public Service Company (Xcel) and other industrial customers. The projected demands for these users are based on historical figures and future projections. The Cherokee Power Plant and the Park Hill Golf Course are users who are already enrolled for recycled supply. The total demand for this phase is about 6,600 acre feet.
The second phase will be constructed as development takes place at Stapleton and Lowry Redevelopment, Rocky Mountain Arsenal, Green Valley Ranch, Gateway and the Denver International Airport (DIA) area. Supply at Stapleton and Lowry will be used for the irrigation of anticipated parks, golf courses and commercial centers. The Arsenal, which will be converted into a national wildlife refuge, will use the water to maintain lake levels on site and to provide water for wildlife habitats. A number of Montbello parks may also be converted to reuse water service in conjunction with Green Valley Ranch and Gateway during this period. A dual distribution system already has been installed at DIA. These facilities are currently receiving potable water service. When Phase II construction of the recycled water system is completed, recycled water will be delivered to the airport facilities to serve the heating and cooling system, irrigation and car washing facilities.
The total recycled water project demand is approximately 15,300 acre feet and is estimated to cost about $139 million ($9,100 /acre foot). Treatment Plant construction is scheduled to begin in January 2001. Service for Phase I should begin in 2003. The recycled water project cost compares favorably to the cost of development of new structural supply, and has minimal environmental impacts. This project will enable Denver Water to extend its water resources, providing for the needs of the metro area in the future.