Phoenix officials outline operations, environmental protections and cost savings at SR 85 landfill

Public works officials on June 18 told the Transportation Infrastructure and Planning Subcommittee that the city’s State Route 85 (SR 85) landfill in Buckeye is meeting environmental protections while the department pursues technologies and operational changes to extend the site’s life and reduce capital costs.

The presentation, led by Public Works Director Felipe Pamareno and delivered principally by Assistant Public Works Director Lori Zaldesteller and Deputy Public Works Director Chris Fine, described the landfill as the city’s primary disposal site. Zaldesteller said the landfill “serves more than 420,000 single-family residential customers of the city of Phoenix” and takes in about “1,000,000 tons of garbage each year.” She also noted the site houses a 10-megawatt solar plant built in partnership with APS that began operating in 2015.

The subcommittee was shown the site’s multilayer environmental protections and monitoring systems. Chris Fine described the landfill’s liner system, leachate collection, groundwater monitoring wells and gas-collection probes, and said the facility operates a flare station that “destructs [landfill] gas at 99% efficiency” to prevent harmful gases from escaping. Fine also detailed dust-control measures including use of recycled asphalt millings and water trucks, and movable litter screens to prevent wind-blown debris from leaving the site.

Zaldesteller and Fine emphasized permitting, engineering and technology that have improved airspace management — the landfill term for remaining capacity — and cut capital costs. Fine said a Maricopa County permit modification and revised cell design reduced excavation and the 10-year cell development cost from about $32,000,000 to $16,000,000. He described GPS-guided equipment and quarterly digital surveys that track compaction and remaining airspace; those technologies, he said, have “doubled the life expectancy” of the landfill.

The presentation also highlighted a staff-driven operational change: to delay switchover to Cell 2, landfill crews found additional usable volume within Cell 1. Fine said that since October, operations captured about 400,000 tons of additional airspace — roughly “40% of the garbage we collect in a year” — yielding an estimated $1,600,000 in savings and buying time until Cell 2 construction and its gas-collection system are completed.

Officials described ongoing and planned capital work: finishing construction of Cell 2, designing the Cell 2 gas-collection system, rehabilitating water-supply infrastructure used in operations, heavy-equipment replacement, landfill capping of closed cells and development of early-detection and suppression systems for lithium-ion battery fires. Fine said most of the landfill’s active wells are horizontal collectors and spaced at roughly 150 feet — a tighter spacing and horizontal configuration the department considers more aggressive than earlier industry practice.

Subcommittee members praised staff and asked questions about groundwater and gas monitoring frequency and how the city applies landfill technology and monitoring to closed sites. Zaldesteller said most monitoring is performed monthly; she added that if a newly installed system shows elevated parameters staff will sample at daily or weekly intervals for 30, 60 or 90 days. Pamareno said the city maintains five closed landfills and pursues reuse options such as solar arrays on capped sites when appropriate.

The discussion concluded with subcommittee appreciation for staff performance and a short tour suggestion.