EPA has identified source reduction as a suggested area of focus in a broad-based approach to managing PFAS compounds. Pretreatment ordinances have historically been used by utilities and municipalities on other contaminants of concern to reduce the loading to downstream wastewater treatment plants. It is far easier to address 100 gallons of PFAS-containing effluent while it is still at its source than to treat it when it becomes diluted in millions of gallons of water entering a water or wastewater treatment plant each day.
Industrial facilities and manufacturers are not currently required to track or report discharges of PFAS into municipal collection systems. But that is likely to change based on EPA’s recently released Effluent Guidelines Program Plan 15. These plans historically have been issued biennially and used to set limits on specific pollutants introduced to publicly owned treatment works collection systems by industries and manufacturers.
Plan 15 suggests that effluent limitation guidelines and treatment standards are warranted for reducing PFAS discharges from some industries, including metal finishing, chemicals and plastics. EPA plans to conduct rule-making on PFAS discharges for these industries. Studies are also planned on PFAS discharges from landfills, textile and carpet manufacturers, and the electrical and electronic components industry.
Discharge limits for upstream sources of PFAS will potentially prevent or reduce the need for significant PFAS treatment at water and wastewater treatment plants. This approach may also reduce the need for alternative disposal methods for biosolids. Utilities can begin conversations with industrial customers now, supporting efforts to fast-track the PFAS identification process and find ways to pretreat PFAS compounds or minimize their generation.
Accounting for source reduction can be an important component of a process evaluation, which includes:
Monitoring and Measuring PFAS at Drinking Water Treatment Plants
When conducting a process evaluation, a utility’s water treatment operation merits early attention. EPA’s initial PFAS rules will likely focus on utilities’ water treatment operations.
While more than 6,000 PFAS compounds have been identified, only 256 are reported to have been commercially produced over the past 60 years. Some of these compounds have been named by EPA as contaminants of concern and assigned a health advisory level.
Beginning in 2023, EPA will require drinking water utilities to measure 29 of these compounds as part of Unregulated Contaminant Monitoring Rule 5. Within one to two years, EPA is expected to specify maximum concentration levels (MCLs) for select PFAS compounds and to consider regulatory action on groups of PFAS supported by the best available science.
It is therefore critical for water utilities to understand the PFAS makeup of water entering their water treatment plants. By tracking the presence and concentration of these compounds, how they are treated and where they go next, utilities can put themselves in a position to predict if and how PFAS rules may impact operations, as well as assess options when EPA announces the action threshold for PFAS removal. Characterizing source water to understand its chemistries can also influence treatment technology performance.
Should the water entering a water treatment plant exceed action levels for PFAS, current treatment strategies will be limited and likely require two or more technologies in series. Current technologies — granular activated carbon, reverse osmosis and ion exchange — are a good start and have potential. But each is limited by what PFAS compounds it can remove, how they are concentrated and where they can be disposed.
Even if a utility discovers that the PFAS concentration in its finished water falls below actionable levels, PFAS compounds can accumulate in the water treatment residuals, concentrates and solids that are often passed on to a wastewater treatment facility or enter other waste streams. Current operational practices of sending concentrated solutions or solids to wastewater treatment plants, landfills, wells or land applications could potentially be prohibited under future PFAS regulation.
PFAS concentrations will continue to persist in the water cycle, making it imperative for utilities to understand downstream impacts before the water or waste streams leave the water treatment plant.