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  • No landfill in this landscape: Bright future for Ina Road site

    An old County landfill is getting a new lease on life that will save money, benefit farmers and spruce up an area popular with pedestrians, cyclists and tourists.  

    The Ina Road Landfill, located on the east bank of the Santa Cruz River south of Ina Road, will be covered with soil, revegetated, and later hold solar panels for a Regional Wastewater Reclamation Department project.

    “The landfill reached its capacity and is no longer in use,” said Nancy Cole, Director of Pima County Capital Program Office. “Because of the limited potential uses of decommissioned landfills, we wanted to work with other County departments to find a creative reuse for the area.” 

    That reuse was identified at the County’s Tres Rios Water Reclamation Facility next to the landfill. The inevitable byproduct of the wastewater treatment process are biosolids. As the name indicates, these are the remaining solids after the treatment process is completed. 
    CDO and Santa Cruz
    The material is essentially composted waste that has gone through a process known as digestion. The resulting biosolids are rich in nutrients and used as fertilizer for many agricultural products.  

    Despite the name, however, biosolids are far from solid. In fact, the current process leaves about 80 percent water. While still a high-quality fertilizer product, the higher water content limits the available uses. 

    “Every time we haul biosolids we’re hauling water,” said Jeff Prevatt, Deputy Director for Pima County Regional Wastewater Reclamation Department. 

    Once this landfill-turned-biosolid drying facility is completed, water content will be reduced to roughly 20 percent water. That will mean fewer trucks transporting biosolids to farms. 

    Prevatt said as many as 12 truckloads per day are hauled to farms at an annual cost of nearly $2 million. With a drying facility completed, only about two truckloads would be hauled away each day, saving the County on fuel costs.

    In addition, the dried biosolids act as a slow-releasing fertilizer, which holds less risk of leaching into groundwater. 

    Dried biosolids also can be used in more agricultural settings. Prevatt said the current high-moisture content is considered a Class B product, which can only be used on privately owned farmlands. Dried biosolids are Class A quality and allowable for use on state-owned farmlands, which many farms lease for use. 

    Prevatt said the department intends to power the drying facility with solar energy. The solar arrays would be installed on a portion of the closed landfill and power the drying facility on the adjacent RWRD property. 

    The Regional Flood Control District also lent a hand in the landfill project. 

    The acquisition agreement the Flood Control District has with the nearby CalPortland manufacturing facility ensured access to fill dirt needed to cap the landfill. CalPortland had been stockpiling the material, essentially unneeded for the manufacture of cement, but exactly what was needed for this job because of high levels of silt and clay. 

    Once the 24-inch layer of the material is added, it will dry to create a firm cap over the landfill, which will prevent erosion and water infiltration. The site will later be hydroseeded to promote plant growth and further protect from erosion and runoff – a vast improvement from its days as a landfill.

    The closure process will be done under the direction of Pima County Department of Environmental Quality Solid Waste Management Division.

    The landfill operated for more than five decades, receiving municipal solid waste in the 1960s and 70s and then construction debris and landscaping off and on from the late 70s until it was closed in June 2010. Following certification of final closure by the Arizona Department of Environmental Quality (ADEQ), a 30-year, post-closure maintenance and compliance monitoring period will begin.

    During construction, trucks and construction equipment will need to cross the Chuck Huckelberry Loop near the confluence of the Cañada del Oro Wash and the Santa Cruz River. A ramp installed will protect the Loop path from damage. 

    While the work won’t close the Loop, there will be flaggers on site to make sure vehicle crossings go safely. Work hours are scheduled from 2 – 10 p.m., Mondays through Fridays. Construction is expected to last through November. 
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