MSD is proposing to construct an anaerobic digester facility at the Little Miami Wastewater Treatment Plant and anticipates the “beneficial reuse” of the resulting biosolids. Biosolids, derived from sewage sludge, have been land or surface applied for “beneficial reuse” on crop and range lands in many US communities. USEPA has acknowledged that biosolids may contain levels of PFAS and PFOS which would exceed EPA’s acceptable risk thresholds. Scientific literature also acknowledges that biosolids may contain pharmaceuticals that are not destroyed by anaerobic digesters. Heavy metals coming from industry, consumer products and stormwater runoff are also not destroyed by anaerobic digesters but pose risks to soil, water, humans and ecosystems. Toxics from industrial waste may also be present in sewage sludge.
Sierra Club Miami Group has submitted a comment to MSD opposing “beneficial reuse”, and urges the county to seek alternatives.
Anaerobic digestors typically remove pathogens from biosolids, but numerous other toxics in biosolids can be human health and ecological threats. Land application of biosolids may become a liability to the city and county.
Sierra Club Miami Group does not oppose the construction of an anaerobic digester at the LMWWTP, as it may be the least harmful of the available options. Other processes for sludge management include incineration and landfilling. None of these are desirable.
SCMG recommends that sludge from the LMWWTP be sampled and analyzed for a broad suite of PFAS and pharmaceutical chemicals, along with other potential contaminants, on a regular schedule, to fully characterize the potential hazards associated with human and environmental exposures.
SCMG opposes the land application of sewage sludge and biosolids. Sierra Club recommends that the city and county forego the “beneficial” use of biosolids and instead manage them in a manner which does not allow discharges of leachate and is not near human habitat or waterways.
SCMG further recommends that the city and county seek a state-wide ban on the use or sale of products containing PFAS or PFOS or other “forever chemicals”.
SCMG also recommends that MSD phase out the industrial and commercial discharges to the sewer system. While MSD has allowed these toxic discharges, and derives revenue from them, the contaminants are still in sludge after treatment and are discharged into waterways, or into the air using incinerators.
SCMG looks forward to the time when MSD sludge is contaminant free and can be safely used for its significant nutrient value. Unfortunately, that time is unlikely to come soon.
