Cape Fear Public Utility Authority staff will spend the next fiscal year examining health, environmental, financial, and other implications of various options for managing biosolids, with the goal of developing a long-term, sustainable strategy for the community.
Biosolids are material that remains from wastewater after undergoing treatment at the community’s wastewater plants. Before water from the treatment plants can be discharged to the Cape Fear River, solids must be removed from the water and treated for offsite disposal. Last fiscal year (FY18, July 1, 2017, through June 30, 2018), CFPUA managed 24,276 cubic yards of biosolids, enough to fill more than 1,000 dump trucks.
Utilities typically have three disposal options for biosolids management:
Landfilling: Transporting biosolids to a landfill approved to receive them.
Land application: Transporting biosolids treated to a higher level to regional farms to be used as fertilizer for crops not intended for human consumption.
Incineration: Burning the biosolids in a separate facility and disposing of remaining ash.
In the past, CFPUA generally has managed biosolids through land application, the most common biosolids disposal method among wastewater systems in North Carolina and nationwide. Biosolids contain large amounts of beneficial organic material, giving farmers an alternative to industrial fertilizers.
Land application is endorsed by the U.S. Environmental Protection Agency, which describes biosolids as “nutrient-rich organic materials resulting from the treatment of domestic sewage in a treatment facility. When treated and processed, these residuals can be recycled and applied as fertilizer to improve and maintain productive soils and stimulate plant growth.” Land application is regulated through a permit process managed by the North Carolina Department of Environmental Quality (NCDEQ).
Since October 2018, however, CFPUA has been transporting its biosolids to a lined landfill, which is significantly more expensive than land application. This occurred in part because of field conditions: Regulations prohibit land application on fields with standing water. Ultimately, CFPUA opted to continue using a landfill while it began formulating strategies to characterize sources of PFAS in biosolids and take steps to reduce those contributions.
Biosolids facility at CFPUA's Southside Wastewater Treatment Plant
Regulations require regular testing of biosolids to determine their chemical, physical, and biological components. Emerging compounds such as PFAS are not included in these tests. Nevertheless, CFPUA proactively began testing its biosolids for PFAS in 2017. Additional testing was conducted this year. PFAS compounds were found in each test.
PFAS, or per- and polyfluoroalkyl substances, is a class of chemicals that includes thousands of compounds. Little is known about the potential human health effects of PFAS. Research on the most-studied PFAS, PFOA and PFOS, indicate they pose a number of risks to human health, including effects on the liver, development, and immune system, and may be carcinogenic. Accumulating scientific data on newer PFAS compounds such as GenX have led researchers to believe these may pose similar health risks to humans
It is important to note that the PFAS compounds and other emerging contaminants found in biosolids are not created in the wastewater treatment process. They are contained in the influent that flows to our plants from a variety of sources, including businesses, homes, and inflow and infiltration from the Cape Fear River and other surface waters.
In many ways, these compounds are artifacts of modern life. PFAS-based materials are found in a wide variety of products, from electronics and solar panels to waterproof clothing, safety gear, and dental floss. They can wind up in the wastewater system from manufacturing processes as well as from washing dishes and doing laundry.
For example, the North East Biosolids & Residuals Association reports that PFOA, one of the most-studied legacy PFAS compounds, was found at levels as high as 2,370 parts per billion (ppb) in cosmetic foundation makeup and 142 ppb in dust in daycare centers. While upstream dischargers such as Chemours are responsible for many of the PFAS found in the biosolids at CFPUA’s wastewater treatment plants, the community at large also contributes. This is true not just for CFPUA and its customers, but for virtually every other community.
CFPUA is unaware of any other public utility in North Carolina that has tested its biosolids for PFAS. In early May, NCDEQ announced it will require CFPUA and 24 other utilities and municipalities to begin testing the wastewater that flows to their treatment plants for PFAS and 1,4-dioxane, a compound used in industrial solvents and other products, as “part of an ongoing management strategy to address some of these compounds in surface water and biosolids.”
Even before NCDEQ’s announcement, CFPUA had begun testing its collection system to try to trace PFAS compounds to their sources. This work is ongoing and is a potential first step toward efforts to reduce concentrations in the influent and, as a result, in biosolids.
Landfilling is more expensive than land application for biosolids management. As of March 2019, CFPUA had spent more than $1.3 million for biosolids disposal, exceeding the amount designated for this purpose in its 2018-19 fiscal year budget. On May 8, the CFPUA board voted to allocate an additional $500,000 to fund continued landfill disposal through the end of fiscal year, which runs through June.
Staff is revising the proposed budget for fiscal year 2019-2020 to provide sufficient funds to continue sending biosolids to a landfill. The CFPUA board will consider that budget for approval at its June 12 meeting.
Over the next several months, CFPUA will continue to conduct strategic sampling to help characterize potential sources of PFAS in the wastewater system. Based on the results, staff will work to create a community-wide approach to reducing PFAS in biosolids. In addition, staff will study the implications of biosolids management options and consult with researchers, regulators, and others to develop a long-term strategy.