How should WWTPs manage PFAS in Biosolids?

 PFAS are everywhere. Water reclamation facilities, though, bear the burden of receiving these compounds, even though they are just passive receivers of the toxic substances. 

Currently, what is the overall challenge that water reclamation facilities face when it comes to biosolids?  

You have done extensive cost analysis research on this topic. Can you share more about the study and your findings?  

In 2021, we worked with the Water Environment Foundation (WEF) and the Northeast Biosolids and Residual Association (NEBRA) to develop a cost study. We surveyed twenty-eight facilities across the country and inquired about their biosolids management costs and their fluc­tu­a­tions over the years. We have been seeing vast impacts on end-use cost. From 2018, which was around when PFAS hit the map for water reclamation, to 2021, we saw a 72% average increase in end-use cost.

Since then, there have been even more dramatic increases in Maine. As a state with a moratorium on land application, we've seen up to a 300% increase. In other states, including some facilities in Mass­a­chu­setts, there have been increases as dramatic as 200% before having regulations in place. Overall, we are starting to see dramatic impacts on these utilities. 

Because the EPA has not yet set any limits or regulations on PFAS in wastewater and biosolids, have you noticed any common themes or methods for mitigation and disposal on a state-by-state basis? 

The state of Michigan has had a pragmatic approach to measuring PFAS in the wastewater by cate­go­riz­ing facilities that are industrial-impacted and non-industrial impacted. They have also started working with their industrial pretreat­ment programs to identify the industries that are discharging PFAS-laden wastewater and putting in pre-treatment for best management practices. 

In one case, I spoke to a facility in town, and they were able to talk about using just carbon filtration before sending to the collection system, and it decreased their PFAS concen­tra­tions in the plant. Michigan is a great example of a state that has a proactive approach to combating this problem. 

Other states are taking different approaches. Mass­a­chu­setts is modeling PFAS from finished biosolids in the soil column and into the groundwater below. They are also thinking about applying drinking water limits to that groundwater and their models. This is a very science-based approach, but the challenge there is that different PFAS compounds migrate in different ways, and we do not yet understand the toxicology of these compounds. 

To summarize, what is your elevator pitch on the challenge of PFAS and biosolids? 

We need to do this prag­mat­i­cally with a science-based approach. Right now, there is fear around PFAS and we need to advance the science to understand how we can mitigate this problem properly. To do this, we must understand what our sources are, and to do that we need to do these sampling programs that many utilities are already starting.

We also need to understand the toxicology. Much of the research and development that CDM Smith is doing addresses how these compounds migrate through the environment. There are so many benefits to be gained from water reclamation facilities, whether it's the fertilizers that we produce in biosolids or energy that water reclamation facilities can produce. We need to continue to take advantage of these benefits, especially as biosolids contain phosphorus. Phosphorus is one of the three key components of life on Earth, and it is finite; instead of destroying biosolids, we need to understand how to safely use them.  

Even our blood is cont­a­m­i­nated with PFAS, but we need to understand what those levels are and what are those exposure pathways to humans so that we can continue to use biosolids and continue to see the PFAS concen­tra­tions drop. This could be from companies promising to not use them in their manu­fac­tur­ing, local ordinances eliminating use of certain packaging or source iden­ti­fi­ca­tion and reduction. As mentioned in that case in Michigan, where they worked with industries to treat their discharges and decreased PFAS concen­tra­tions, that facility may potentially get to a point where they can start bene­fi­cially reusing their biosolids again, which is the inherent goal. 

For more details on Eric's research, see our report on PFAS' impact on biosolids costs.