A Biosolids Research Update from Sally Brown, University of Washington 

MORE PFAS

Just when you thought that with all the COVID frenzy and the cool stuff about wastewater- based epidemiology that people might forget about PFAS, it rears its ugly head.  I got a copy of an article in Waste Dive all about the evils of PFAS and how it is going to stop biosolids and compost use.  While I can’t bring myself to read it, I took it as a sign to do a PFAS library update.  Here is the link if you are braver than I am: 

 https://www.wastedive.com/news/pfas-chemicals-organics-recycling-compost-biosolids/587044/

All the papers in this library are new, published in 2020. Hopefully, they will broaden the understanding of PFAS in the environment, the role of biosolids and composts, and what to do about it (not have a nervous breakdown).  The first article (PFAS concentrations in soils: Background levels versus contaminated sites) is a survey on soil concentrations of PFAS, PFOA, and related compounds.  The authors went over all the published literature and also did a deep dive into US Airforce records.  Articles included in the survey are from all corners of the globe and ALL the sampled soils had PFAS and PFOA above detection limits.  Granted, detection limits were very low.  But you find this sh*t in the Arctic!  They separate the soils into three general categories: non- contaminated sites, primary contaminated sites, and secondary contaminated sites.  Primary include direct source contamination such as firefighting foam and manufacturing.  Secondary include land-applied biosolids, contaminated wastewater, or proximity to manufacturing.  They reported the highest concentrations from each study.  The paper itself has the details on sources, locations, and paper references, but here is the grand summary: 

The authors have 3 papers cited for secondary manufacturing that include biosolids applications.  One of them has biosolids and paper sludge.  The two biosolids only range in PFOS from 0.4-878.  The one that has the combo has 1692.  

The paper also has a section where they compare soil concentrations to groundwater concentrations.  Based on data from Air Force sites the ratio of soil to water varies by 9 orders of magnitude.  13% of the sites had higher water than soil concentrations.  The remainder had the reverse pattern with a peak ratio of 2- (log scale here) meaning 100x more in soil than in the water.  Here is their conclusion: 

In summary, the results of this study demonstrate that PFAS are present in soils across the globe, and indicate that soil is a significant reservoir for PFAS. A critical question of concern is the long-term migration potential to surface water, groundwater, and the atmosphere. This warrants increased focus on the transport and fate behavior of PFAS in soil and the vadose zone, in regards to both research and site investigations. 

The next paper (Extending the knowledge about PFAS bioaccumulation factors for agricultural plants – A review) is a review of plant uptake.  The authors have looked at the studies done in hydroponic systems but used only the ones done in soil systems.  This is very important, as hydroponics often greatly overestimate uptake in comparison to soils.  There is an amazing diagram, like one of those posters you hung on your dorm room in the 70s that shows the number of studies by plant group and length of carbon chain. 

The take-home of this paper is that the longer chain compounds are not taken up into plants but that the shorter chain compounds are.  Almost all uptake is limited to the vegetative part of the plant and not the reproductive part.  That is great if you are eating wheat but not so good for lettuce. 

The third paper (Characterizing and Comparing Per- and Polyfluoroalkyl Substances in Commercially available biosolid and organic non-biosolid-based products) reports on concentrations in biosolids and compost products.  It comes from Rooney Kim and Linda Lee from Purdue, so a very capable research group.  The authors tested a range of products with an emphasis on biosolids based products.  These included several heat-dried biosolids, biosolids compost, and biosolids–based blends.  Only one food/ yard compost was tested.  One would expect that food/yard materials (A below) would have elevated concentrations relative to mushroom composts.  The biosolids based materials had higher concentrations with high variability across the different products.

Concentrations also decreased over time.

So, with all the fuss, things are improving as the use of the longer-chain compounds is being phased out. 

The 4^th article (Landfill leachate contributes per-/poly-fluoroalkyl substances (PFAS) and pharmaceuticals to municipal wastewater) addresses a potentially unexpected source of these compounds into the wastewater stream: landfills.  This makes sense.  All that old carpet must go somewhere.  Those old Scotchgard clothes, popcorn bags, Teflon pots, and pans.  In other words, all of those old PFAS impregnated items from our homes that make home exposure the biggest pathway of concern also make landfills a major repository.  Perhaps, instead of sampling soils like in the first paper, scientists should be sampling landfills.  Turns out that landfill leachate is a major source to treatment plants:

PFAS were detected more frequently in leachate (92%) than in influent (55%). Total PFAS concentrations in leachate (93 100 ng L−1) were more than 10 times higher than in influent (6950 ng L−1) and effluent samples (3730 ng L−1).

Time to get the pre-treatment staff out on patrol. 

So, these compounds are in all soils.  The short-chain ones, the ones that are still being made and used, are also much more plant available than the longer ones.  Because they are so ubiquitous, they are entering treatment plants from landfills.  

Do you ban the biosolids?  The final article in the library (A framework for the regulation of new and existing PFAS) says that what you do is regulate the compounds from the source.  This is a policy paper that describes the regulation of the compounds.  Do not just ban the big ones, consider all of them as a single class.  Prohibit their use when they are deemed non-essential.  This is an answer that makes sense.  It will take time to get past the age of non-stick, but this is the pathway to do it.  

TOPICS - Back to Nature with Biosolids

One effect of the Covid-19 pandemic is families heading “back to nature” in Philadelphia’s parkland, a pattern which I believe has been seen across the globe. Nature can ground us in our ancestral roots, as affirmed in the podcast of this past week’s On Being, an interview by Krista Tippett with environmental journalist Michael McCarthy: Nature, Joy, and Human Becoming .  McCarthy says we ought to “stop relying on the immobilizing language of statistics and take up our joy in nature as our defense of it.”  Human beings have lived as part of nature for 50,000 generations, but only 5 most recent generations have had humans disconnected from nature by urbanism.  Do we really need science to tell us that we need nature?

Cities and industrial agriculture have disconnected human beings from the very “facts of life” that make biosolids seem “natural.” I propose that we embrace “back to nature” as our theme for engaging the public, as we call for people to acknowledge the basic fact that their own “output” is “input” for others in the great circle of life.

Public engagement is an initiative of the Water Environment Federation as it create a “biosolids communications toolkit.” The toolkit project is an outgrowth of the Biosolids National Convening in 2019. The project is being fleshed out by the firm Raftelis, with involvement of the Residuals and Biosolids Committee.  The toolkit will offer templates for pamphlets, social media, bill stuffers, and flyers that can be used to convey biosolids information.

WEF has solid groundwork for this toolkit.  This was set by the 2016 Biosolids Messaging Book, and by two research reports of the Water Environment Research Foundation (available through IWA Publishing): Public Perception of Biosolids Recycling: Developing Public Participation and Earning Trust and A Strategic Risk Communications Process for Outreach and Dialogue on Biosolids Land Application. For communications training we can also take in a great webinar (Sharing the Biosolids Story with the Public) and check out this WEF conference presentations (e.g., Developing a Biosolids Strategy with the Community – A Modified Approach to Long-term Biosolids Planning at the Region of Waterloo).

To understand messages, we can go to the historic record of media coverage. 

Could “nature” be the principal theme for this toolkit?  Geologist David Montgomery makes the case  in his book Growing a Revolution: Bringing Our Soil Back to Life. He devotes Chapter 12 – Closing the Loop to the topic of returning human waste to soil, and we have Dr. Sally Brown and Tacoma to thank for Montgomery’s support.  He provides to biosolids recycling the context of history.  He shows that 150 years ago, the book The Natural Laws of Husbandry, by German chemist Justus von Liebig, had called for the  return of human and animal waste to restore fertility as the “experience of a thousand years.”  An influential book in soil science by Franklin H. King’, the 1911 book Farmers of Forty Centuries, shared the same message.  Both are available as reprints on Amazon for the wisdom they still offer us today.

“Back to Nature” is not just a call from the past.  It is an important “meme” for today’s world. This past week I came across two such relevant phrases: “Vulnerably reconnect with nature” was underscored by filmmaker John Chester, and “Nature-based technology” was advised by Dutch environmental professor Cees Buisman.

“Vulnerably reconnect with nature” is John Chester’s final message to listeners of his 2.3 hour long interview on the Rich Roll Podcast (Episode 373). I had interrupted my listening of this interview to watch Chester’s 90 minute, indie film documentary The Biggest Little Farm (2018). It is a wonderful movie about two city folks creating a “regenerative farm.” For me, the message was hard work, aligned with sound science, is transformational. The magic in the movie is the storytelling around nature’s response to science-based biodiversity and sustainable soil principles.

What is more, storytelling around soil health abounds.  Check out Sustainable (2017), Urban Farmers (2017), Living Soil: A Documentary for All of Us (2018), Regeneration: The Beginning (2019), Soil Solution (2019), Kiss the Ground Film (coming 2020). If you enjoy books, perhaps you gravitate to “Dirt to Soil: One Family’s Journey into Regenerative Agriculture.”  But if you enjoy a more academic approach to the topic of soil health, you can go back and view the recent annual conference of the Soil Health Institute “Soil Health: The Foundation for Regenerative Agriculture,” held virtually July 30 and 31. Clearly, humanity hungers for soil health.

“Nature-based technology” is a key approach to “Conscious Innovation Strategy” offered by esteemed Dutch environmental sciences professor Cees Buisman in his extended essay “Humanity is not a Plague.” For Dr. Buisman, consciousness is a redirection of human values toward a global sharing of Earth’s resources, away from self-centeredness and individual greed and toward collective well-being and sustainability. From his viewpoint, municipal systems are a manifestation of a collective commitment to environmental stewardship, of which we should be proud advocates and spokespeople. Humanity hungers for collective actions for sustainability.

These “messages” on nature offer direction to those of us in biosolids.  Our wastewater treatment system is a nature-based technology producing biosolids, a material that encourages us to reconnect with nature in its land application. Yes, we can point to thousands of science journal articles and conference papers detailing the sharp edge of science and engineering, but it is the simple effectiveness of biosolids in nature that provides the compelling case.

Over the past three years, MABA has “clipped” from Google Alerts about 330 biosolids news items. Of all news clips, about a quarter were positive stories about benefits of public agencies producing and using biosolids. The themes of these media articles can be captured in this overview: “Biosolids recycling is a sustainable practice that returns nutrients to the farms, improves plant growth, restores degraded landscapes and reduces waste. Recycling helps the farmer, keeps costs down for the public agency and can provide citizens free soil products.” The central media message of biosolids jibes very well with the “Back to Nature.” But 70 articles over 5 years is not an impressive oeuvre for a nation with thousands of public facilities.

Restoring soils using organic amendments, in urban soils and in overused farmlands, is the starting point for the story of biosolids and soil health. This may seem self-evident, but apparently scientists know this message needs to be regularly revisited. The authors  of Soil Degradation: Will Humankind Ever Learn? express the urgent sentiment: “Two common factors—soil erosion and depletion of soil organic matter (SOM)—emerge as consistent indicators of how “the thin layer covering the planet that stands between us and starvation” is being degraded. Soil degradation is not a new problem but failing to acknowledge, mitigate, and remediate the multiple factors leading to it is no longer a viable option for humankind.” Carbon amendments are necessary for soil health: “Improvements in soil health, along with increase in availability of water and nutrients, increases soil's resilience against extreme climate events (e.g., drought, heat wave) and imparts disease‐suppressive attributes (see Soil health and carbon management .)

Biosolids is a worthy organic amendment for establishing soil health. Several scientists have tracked biosolids for decades.  Sally Brown, University of Washington, has been a consistent research voice for biosolids as an ingredient for healthy soils, is a lead author in Municipal biosolids — A resource for sustainable communities: “Research has shown their value for key components of urban greening including tree, turf, ornamental and vegetable growing, green stormwater infrastructure, and reduction in contaminant availability.” To the benefits of soil health, Dr. Brown adds carbon sequestration benefits, also a part of the “story.” In the paper Building Carbon Credits With Biosolids Recycling, Dr. Brown concludes, “the potential to sequester C, both in the soils and in plant biomass, is clear. If biosolids application for restoration increased soil C content by 2 percent, the credit would be 40 Mg C ha-1.”   Nicholas Basta, at The Ohio State University, is another strong voice: Application of organic amendments to restore degraded soil: effects on soil microbial properties: “In general, all organic amendments increased enzyme activities in 2009 with BioS [biosolids] treatments having the highest activity.” Greg Evanylo at Virginia Tech has dozens of biosolids journal articles, including this very recent one by his graduate students: Biosolids amendments improve an anthropogenically disturbed urban turfgrass system.

Although benefits of building soil health with biosolids have been clearly shown by these scientists, and although these benefits seem from our vantage point to far outweigh potential risks, we cannot afford to ignore risks seen by other scientists.  Microplastics, antibiotic resistant genes, “ecotoxic contaminants” and pathogens have been labeled as concerns. If we ignore these concerns, we imperil our ability to tell compellingly our story of biosolids and soil health. We need more investment in science.  Examples of  recent science journal articles for which we need answers are: Microplastics and pollutants in biosolids have contaminated agricultural soils: An analytical study and a proposal to cease the use of biosolids in farmlands and utilise them in sustainable bricks, Toxic potential of sewage sludge: Histopathological effects on soil and aquatic bioindicators, and How Valuable Are Organic Amendments as Tools for the Phytomanagement of Degraded Soils? The Knowns, Known Unknowns, and Unknowns.  .

Yet, we have had history and science on our side. Thirty years have passed since the first draft of Part 503 regulations, when a scientific community became engaged in assisting with use of sound science in regulating biosolids use. Since that time, over 200,000 peer reviewed biosolids research papers have been published globally.  When the Office of Inspector General released a two years ago a misguided critique of the status of biosolids research, the W4170 Research Committee again stepped up with its scientific case for recycling biosolids in “Response to the USEPA OIG Report No. 19-P-000.”

While scientists can support us with the facts of biosolids, we must become the storytellers. Michael McCarthy in the On Being podcast urged us to not substitute facts for the story. His book The Moth Snowstorm: Nature and Joy has behind it a serious concern for the well-being of the global environment. But, even so, the NY Times Book Review can say of it, “Rather than the dire, dry statistical projections often heralded to make the case for conservation, he turns boldly to joy — to imagination and emotion.” And, we ought to be able to get children involved, as the Vox media's "first-ever week of video programming for kids" is doing with the The secret history of dirt, explained to kids, in which the story line is "dirt helped build civilization, only to get stabbed in the back by us."

In this same way, nature has the possibility of being the platform on which we tell the story of biosolids and its role in building soil health. We in the business of developing a communications toolkit ought to get Back to Nature with Biosolids.