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Operation of the AWTF and ASR well field commenced in February 2001. To date, ASR-1 is injecting at a rate of approximately 500 gallons/minute (gpm) and ASR-4 is injecting at a rate of approximately 475 gpm. Water levels measured at ASR-1 are approximately 155-feet bgs and water levels at ASR-4 are at approximately 117-bgs. ASR-2 is currently non-operational. Full scale permitted operation of the entire facility is expected in the Fall of 2002.
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For years, the Fountain Hills Sanitary District (FHSD) has been trying to develop a long-term solution for the disposal of treated wastewater while at the same time looking for a reliable balanced supply of water for community lakes, parks, and golf courses. Fountain Hills is “land-locked” on all sides so annexing additional land was not feasible, nor was using vacant land within the community due to development pressure. To address this problem, the FHSD looked at various alternatives including discharges to washes, construction of a dam and reservoir, transfer of the wastewater across the McDowell Mountains via a pipeline for disposal in City of Scottsdale sewer system, and regional recharge projects. After several pilot tests using existing wells in the are, it was determined that recharge by direct injection was feasible and met the FHSD’s requirements of an independent solution, water conservation, technical feasibility, and reasonable affordability. Public input was a major component of the decision process. Permits required for construction and operation of the project included reuse and a modified Aquifer Protection Permit (APP) from the Arizona Department of Environmental Quality, approval to construct and approval to operate permits from Maricopa County, and an underground storage permit from the Arizona Department of Water Resources. Static groundwater levels in the area of the project are approximately 240-feet below ground surface (bgs) and the recharge permit limits the recharge to within 50-feet bgs. The main component of the overall project includes a wastewater treatment plant which provides water to reuse customers and the Advanced Water Treatment Facility (AWTF), the AWTF itself which provides water to the three aquifer storage and recovery (ASR) wells, the ASR wells, and five monitor wells. The AWTF provides micro-filtration for removal of turbidity for the purpose of protecting the storage wells. Each of the ASR wells are equipped with three lines; one line is used to inject water into the aquifer, one line is used to pump water from the aquifer, and one line is used to back flush the system and for bacterial testing. One of the major components of each of the ASR wells is a pre-fabricated well vault that costs approximately $100,000/vault, fully equipped and instrumented. Installation of the ASR wells was accomplished using reverse rotary drilling methods with sound blankets where necessary. Aquifer testing and geophysics were conducted on each of the ASR wells to determine aquifer parameters and geologic characteristics. Drilling costs were approximately $180,000/well. The engineering firm of Black & Veatch was responsible for the overall project, and HydroSystems, Inc., was responsible for the ASR portion of the project. |
