Miami-Dade is formally asking for state action that could grant county leaders more flexibility to repurpose ash generated by waste-to-energy incinerators, including one planned to replace the facility that burned down in 2023.
County Commissioners voted unanimously for a resolution by Juan Carlos “J.C.” Bermudez urging the Legislature and Department of Environmental Protection to revise regulatory language and provide guidance that would “facilitate safe reuse of incinerator ash,” potentially blending the material into cement, asphalt and other building components.
Under current arrangements, ash produced by the old Doral plant, which sat in Bermudez’s district, has accumulated at a nearby landfill rather than being processed for reuse.
Commissioner René García, a former Senator, added his name as a co-sponsor to the measure before the vote Tuesday.
Bermudez told Florida Politics last week that without new state parameters, the ash simply continues to pile up, creating what he described as a “fake mountain” looming over the surrounding neighborhood.
He called the situation both a community blight and a lost economic opportunity.
“What if we could use that, sell it and make a little money back, which would help us with the finances of building a new facility, which would be rather costly?” he said. “Other countries are doing it. So are other states, to a certain extent.”
Research supports the idea that ash can serve as an industrial ingredient under controlled conditions. A 2018 University of Florida study found that processed bottom ash could be incorporated into hot-mix asphalt pavement and some concrete blends at modest replacement levels while still meeting minimum engineering standards. The authors cautioned that performance typically did not match virgin-material mixes and recommended expanded field trials, pre-treatment and continuous monitoring to manage variability and durability issues.
A 2021 peer-reviewed study reached similar conclusions, noting that once aluminum and zinc residues were removed through beneficiation, ash-enhanced concrete performed well in testing. Additional research has suggested that modest ash replacement levels can contribute to emissions reductions by decreasing reliance on virgin aggregate and clinker-intensive cement.
Multiple European countries — including Belgium, Denmark, Germany and the Netherlands — actively incorporate incinerator ash into road base, fill material and other infrastructure applications. Nationally, the Federal Highway Administration has stated that neither federal nor most state rules categorically prohibit the use of solid waste ash in roadway materials, provided the material is tested and confirmed nonhazardous.
But significant challenges remain. Waste-to-energy ash can contain heavy metals, chlorides, sulfates and unburnt organic material that require treatment to prevent leaching or structural issues. Further, composition can vary widely depending on feedstock and combustion technology, complicating efforts to establish universal standards.
Higher levels of substitution can weaken concrete or asphalt performance, and the long-term durability of ash-blended material requires further study. Regulatory agencies remain cautious as a result, particularly given potential contamination by trace lead, cadmium, dioxins and furans.
Bermudez acknowledged comparisons to the 2023 state law promoting research into using phosphogypsum — a phosphate mining byproduct — in road materials, which triggered lawsuits from environmental organizations. He argued that ash reuse poses far fewer risks.
“This isn’t anywhere near what the phosphate would be,” he said.
Miami-Dade has been evaluating sites and financing strategies for a replacement waste-to-energy plant since a catastrophic fire shuttered the county’s previous facility nearly two years ago. The county’s cost estimates have soared to as much as $1.5 billion, and construction is expected to take several years once a site is selected.
Commissioners in October set a December date for preliminary site approval. In July, they approved a measure by Bermudez prohibiting construction in Doral, Medley, Sweetwater, the former Opa-locka West Airport site, or within half a mile of any residential area.
