Top: Biosolids biodrying system. Photo courtesy BDP Industries

An article in the November 24 edition of Inside Climate News — “Maine Was First To Ban Spreading PFAS-Contaminated Sludge on Farmland. Now Sludge Is Filling up Landfills” — does a great job of reporting on the continuing fallout following the Maine Department of Environmental Protection’s ban on the land application, sale and distribution of biosolids-based soil amendments that became effective in July 2022. According to the article, “handling sludge has gotten more expensive and more complicated” in the past three years. Casella Waste Systems runs Juniper Ridge, a state-owned landfill, which accepts biosolids from wastewater treatment plants. The material has to be mixed with bulking material before it can be disposed. The Portland Water District, which services 56,000 households and businesses, told Inside Climate News that the District’s trucks are “limited to a 7-hour disposal window, six days a week,” as the landfill needs to ensure there is bulking material ready to mix in with the biosolids before they can be disposed. “If trucks miss their landfill times, the district has problems,” says the article, which quoted Scott Firmin, the District’s General Manager: “Our flows never stop, so it’s not like we can take two weeks off and wait for things to be solved.” A sobering reality is that the Juniper Ridge landfill is projected to be full by 2028.

Solutions to the challenge include upgrading biosolids dewatering equipment and/or drying the solids. For example, BDP Industries markets a biodrying system that heats the solids through the initial stages of composting — using agitation and aeration — to remove moisture with little or no amendment.