MidAtlantic Biosolids Association

July 2024 - Sally Brown Research Library & Commentary

Provided for consideration to MABA members by
Sally Brown, PhD., University of Washington

Historical Perspective

Time for the biosolids time machine. Back to the days when ‘night soil’ was the name. Long before the days of centralized wastewater treatment, human waste was an integral part of cropping systems. That all changed when the connection was made between pathogens in the poop and disease. Centralized wastewater with public health as a focus put resource recovery on the back burner. Nowadays with regenerative agriculture increasingly understood as a key tool for sustainability, organic amendments are valuable again. Will that also hold for biosolids? To see the future, you must first study the past. So, here we go.

The first article in the library, Agricultural use of organic amendments: A historical perspective was written by scientists from the USDA Agricultural Research Service. My lab at USDA when I was a graduate student was right next door to Cheryl, the technician for one of the authors. I can tell you first-hand that these guys knew their sh**t back when they wrote this article in 1992. They talk about the origins of agriculture and how early farmers in 2000 BC understood best management practices including use of organic amendments. They talk about F.H. King, Chief of the Division of Soil Management in the USDA in the early 1900s. He took a trip to the Far East to see how farmers there maintained rich and productive soils over centuries. Here is what he discovered on his trip:

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Anyone remember the theme of Biofest last year?

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Farmers in the near east used legumes and manures to maintain soil fertility. In the Roman empire there was extensive research on agriculture with many important advances in growing systems. Here too, the value of organic matter additions including composting, animal manures and ‘applying sewage wastes’ was recognized. Soil quality was first mentioned by Xenophon, a Greek philosopher in 400 BC. In 1973 Allison wrote that ‘soil organic matter has been considered by many as the elixir of life’. In 1938 - prompted by the dust bowl, WC Lowdermilk, Assistant Chief of the Soil Conservation Service, toured Africa and the Near East to see why once fertile lands had collapsed. He did this to find answers to the soil erosion problems in the US. He recognized the critical importance of controlling soil erosion. What happened instead was that US agriculture veered in the other direction. A shift from mixed crop-livestock operations to monocultures has made matters worse.

Here is a table that sums it up:

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The authors talk about municipal biosolids and the organic components of MSW in the context of their value for agriculture. They were at the USDA when much of the research on the 503s was ongoing and when the Beltsville static pile compost system was developed. They quote from farm bills that recognize the value of organic wastes. Perhaps now would be a good time to revisit that conversation?

Article #2 Sewage: Waste or resource? A historical perspective was written in 1980 by Christopher Hamlin when he was a doctoral candidate in history. A Google Scholar search shows that he went on to publish extensively on water and health. Here he starts with a quote from Victor Hugo, best known as the author of Les Misérables.

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He notes that land treatment of waste was a grand experiment in France in the 19th century but that over-application resulted in fields becoming sewage lagoons. Modern day wastewater treatment solved this problem, creating the potential for an easily recycled resource. By not using these materials he says: ‘We are, it seems, spurning the pennies from Heaven’. Almost as good as Hugo. The paper provides a great history of how widespread recycling of sewage almost happened and why it didn’t. When it was something in everyone’s face every day, people saw the value. With centralized treatment and the growth of cities, the value faded and the yuck factor prevailed. As he puts it: 'The rise of the water closet doomed the night soil business’. Here dilution was not the solution. Instead, use of storm sewers for sewage killed the rivers in Europe. No one likely remembers the summer of 1858 in London - dry and hot and known as the ‘Great Stink of 1858’. This started the public perception of sewage as nasty, foul smelling and dangerous.

From here came efforts to capture the nutrients in the water for subsequent sale to farmers leaving the water clean enough to be discharged into lakes. Sound familiar? Of the range of processes, the most successful was the ABC method - adding alum, blood and clay. To my knowledge, that one, at least in its original form, hasn't lasted. Those that didn’t buy into their ABCs relied on sewage farms. Using untreated waste for irrigation resulted in impressive yields for the farms that were well run. The others with over irrigation did not get such rave reviews. The next development, with us even now, was an understanding of the role of microbes in stabilizing wastewater. Another great quote, 'Ironically, just as we finally learned how to treat sewage, we forgot about it being a resource’. This is a terrific paper and a great read.

To drive that last quote home we go to paper #3 Anthropogenic Dark Earth in Northern Germany — The Nordic Analogue to terra preta de Índio in Amazonia. Here the authors are focused on localized soils in Germany that show that same dark richness of the terra preta soils in Brazil. And while the biochar frenzy started from those soils in Brazil, it wasn’t just char. Rather a combination of residuals, including human wastes, were responsible for the dark soils in Brazil and the dark soils described in this paper. These soils have retained their fertility since the 1100s. You can see it with your own eyes:

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So, how has Germany responded to this knowledge? By banning land application of biosolids.

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To answer that question we turn to papers #4 Nightsoil and the ‘Great Divergence’: human waste, the urban economy, and economic productivity, 1500–1900 and #5 Markets for waste and waste-derived fertilizers. An empirical survey. Paper # 4 provides a history of nightsoil workers and use in Asia in comparison to Europe. The author notes that the fertile soils in Asia, a result of the night soil, were responsible for higher wages and an economic advantage over Europe. Instead of seeing this as a behavior to adopt, Europeans viewed this practice as evidence of their superiority over their Asian counterparts. He describes the ‘waste business’ in Europe and that in Asia. In Europe it was more collect and dump. In Asia - the collected materials were taken to night soil merchant processing centers where the collectors were paid by the pound for what they brought in. To put this in perspective - poop from about 10 households would get you enough cash to buy a 6 month supply of grain. He talks about how the robust nightsoil market kept waterways clean in Japan. Population growth in Japanese cities resulted in a peri urban farming system to supply fresh vegetables, and more demand for night soil. Each acre received between 6-10 wet tons of animal and/or human waste each year. Europe and the US finally started catching on to the beauty of night soil. At least until the 1870s. The switch to synthetic fertilizers happened first in Europe, reducing labor costs and increasing productivity. Letting sewage once again be considered a waste.

The final article takes us to the present. The focus here is on understanding why and where markets exist for waste derived fertilizers. The author notes their efficacy (she likely read up on night soil, too) and their critical role in a circular economy. She starts with a discussion of the oxymoron ‘markets for waste’ noting that by definition, ‘waste’ is not something that one markets. Redefine, repurpose, rename, modify. And stop using that ‘dispose’ word. She then talks about relative costs as a factor. As fertilizer prices go up, there is a tendency for more demand for organics. As landfill disposal and combustion prices go up, composting seems like a very rational alternative. She goes into a range of factors that can influence decisions for or against residuals use. Then she compares and contrasts Switzerland where biosolids is banned and France, where it is often used. She describes concerns about biosolids safety stemming from Mad Cow disease. Ha - a contaminant from long ago and far away. Many companies had started to refuse to purchase foods grown in biosolids. The French government stepped in and held meetings between a range of stakeholders to reassure everyone involved. The fact that most of the wastewater industry in France is run by Suez and Veolia, two large multinational companies that have government support also helped. As of 2012, 73% of the biosolids are used with about 29% of that total composted prior to use. Then we travel to Switzerland. Home of Alps, chocolate and combustion. Here organic standards coupled with the announcement by organic producers that they wouldn’t accept foodstuffs grown in biosolids lit the fires of those fluidized bed facilities. Beneficial use of biosolids fell from 55% in 1994 to 29% in 2002. It disappeared completely by 2010. Concerns about safety and socio-political factors were the death hammer here. In Switzerland, small municipalities that did not work together to change regulatory and public opinion were no match for ‘scientific uncertainty’. In France, large private companies with political power were.

So, where are we in the US? For an interesting perspective on that and some excellent advice, I encourage you to listen to this month’s Master Class where Dan Thompson, formerly the head of Tagro talks about his experience.

Sally Brown is a Research Associate Professor at the University of Washington, and she is also a columnist and editorial board member for BioCycle magazine.

Do you have information or research to share with MABA members? Looking for other research focus or ideas?

Contact Mary Firestone at [email protected] or 845-901-7905.

Important Update for MABA Members:
Results from the 2nd National Survey of Biosolids Regulation, Quality, End Use and Disposal in the U.S.

The National Biosolids Data Project (NBDP) has been recently unveiled. You are invited to its comprehensive, user-friendly, data-rich website: http://biosolidsdata.org. This website provides both a national overview of biosolids generation and utilization/disposal in the target year 2018, but, importantly and most usefully for practitioners in the mid-Atlantic region, the NBDP also includes state summary reports. Your MABA staff and volunteers are assembling a webpage which will allow quick access to the state reports in our region.

This NBDP data site was prepared over a two-year period. It was accomplished on a shoe-string budget of about $60,000, with a small EPA grant and some financial contributions from WEF, NACWA and public agencies, and with many hours of volunteer time. The focus is comprehensive, with details on technologies, particularly the distinction of Class A and Class B levels of pathogen treatment, with categories of utilization outlets and products (compost versus pellets), with capture of landfill and incineration disposal, and with an overview of each state’s regulations.

A key feature of the project was the survey of water resource recovery facilities (WRRFs), generators of biosolids. The survey had 452 valid and representative responses from WRRFs in 43 states and DC. This is a set that comprises a flow of about 12,000 MGD, or 34% of total municipal effluent flows in the United States. When generously supplied by public agencies, surveys provided in addition to mass of biosolids and uses, information on pollutant concentrations, program costs and points of view on hurdles and barriers. In a few cases, the surveys of state officials were able to elicit information on septage management. The EPA biosolids records for 2018 in ECHO (Enforcement and Compliance History Online) was also brought into the analysis.

Every effort was made to provide comparable data across all states, but this goal was elusive. In the end, the data reports of 32 states were judged of high confidence, 12 were of moderate confidence and 4 of low confidence. Every state office responsible for biosolids management was afforded an opportunity to review and correct its state’s data and description.

While this richly compiled database might clearly have commercial value, the results are freely available and are intended to aid in the transparency of biosolids programs to the public.

Ned Beecher, for 20 years executive director of NEBRA and then special projects coordinator for the early PFAS response, is the principal investigator for this “second” survey. He was the principal designer of the two surveys (one for state officials and the other for public agencies) and of the database, though with much feedback along the way, Ned had been also the leader of the first survey, which was released fifteen years ago, July 2007, based on biosolids generation and use in 2004, which explains in part the ambitious goals of the current survey.

Many biosolids practitioners over the years had come to rely on this first survey. It was clear to all who used it recently that the first survey had become dated. Ned took on this herculean project, and now with its completion, we can give hearty kudos to Ned for his vision and persistence. Today you will note from Ned’s email communications that he is now the “former” special project manager for NEBRA and available for hire. But updates to the second survey, whether to correct or amplify it, or to change it to reflect new developments, will need to be shouldered by others, and we await these folks to emerge and step forward.

The survey year of 2018 may have the feel of “historical” today. But, at the opening of the project in mid-2020, this was the year most likely to be complete in its data set from federal, state, and municipal sources. The project was intended to be completed by Spring 2021, but whether a victim of pandemic staffing challenges or from competing issues for biosolids practitioners, data collection for this new survey was a slog. In the mid-Atlantic region, the year 2018 had an atypical influence of large rainfall volumes, and in the Northeast region the discovery of perfluoroalkyl substances disrupted programs.

Here is the big reveal! Total biosolids used or disposed of in the U. S. in 2018 was 5,823,000 dry metric tons (dmt). This compares to 6,132,000 dmt reported in the 2004 survey. This decline in total biosolids was a surprise to the NBDP team. The decline may reflect less double counting than in 2004 of solids hauled from small to larger plants for treatment, or in some locations it may reflect a shift from alkaline stabilization to digestion, the latter technology reducing total dry solids. The 2018 database involved fewer estimations, particularly of biosolids production at small WRRFs. With the estimation in this second survey of the sewered population served, the total national average per capita production of biosolids annually is 37 pounds. That agencies and states show a wide range around this average suggests other aspects at play, perhaps the proportion of combined sewer systems and the acceptance of septage from unsewered areas.

Here is the second big reveal. Fifty-three percent of biosolids produced in the United States in 2018 were beneficially used. Within this number are some important findings. More Class A EQ biosolids are being produced in 2018 than in 2004. Despite policies for organics diversion from municipal waste landfills in some states and regions, the same percentage of biosolids are commingled with municipal waste in 2018 as in 2004. The percentage of biosolids fed to incinerators has declined, with a fewer number of sewage sludge incinerators in operation. The survey showed, too, decreased full time equivalent (FTE) employees regulating biosolids at state and federal agencies. As our industry has asserted in the past, the proportion of our nation's croplands receiving biosolids as a nutrient source is very small, less than 1%.

The Mid Atlantic Biosolids Association participated in the NBDP project. It reviewed electronic record reports to the EPA and state environmental agencies, and also surveyed state officials and larger public agencies. In the work covering the 7 states and one district in this region, the NBPD documented that the over 1,800 significant POTWs serve 50 million “sewered” customers, producing 1.3 million dry tons of biosolids annually. Sixteen WRRFs in the region produce over 10,000 dmt. NYCDEP is largest agency (~100,000 dmt), and in descending order are Philadelphia Water Department, DC Water, Passaic Valley Water Commission, Middlesex County Utility Authority, Baltimore Department of Public Works, ALCOSAN (Allegheny County, PA), Hampton Roads Sanitation District (VA), City of Rochester (NY), DELCORA, Bergen County Utility Authority (NJ), Suffolk County (NY), Arlington County (VA), Nassau County (NY), and Fairfax County (VA). The average per capita annual biosolids production in the MABA region is 54 dry pounds.

The NBDP state reports include narratives describing notable facilities and programs that serve to treat and use biosolids. In the MABA region report are these distinctive points. Composting is a major treatment technology in the region (e.g., Burlington Co, Rockland Co, Baltimore, A&M Composting, Natural Soils, Spotsylvania (VA) and many small facilities). Two new, large compost facilities under development in reach of Philadelphia. DELCORA and ALCOSAN are large utilities with sludge Incinerators; others in NY (Rochester), NJ (ACUA) and VA have upgraded to meet new MACT standards. The US’s principal service companies, Synagro and Denali, have main offices in the MABA region and serve hundreds of agency clients NYC is the sole large facility in the US without a pathway to Class A EQ products. PVSC is the exclusive example of a long-tested Zimpro wet oxidation solids treatment, and this agency accepts solids from dozens of agencies. Co-digestion with high strength organic waste has great reference facilities in the MABA region (Rahway Valley SA, Lehigh County Authority, and Hermitage, PA). Landis Sewerage Authority in Vineland NJ is arguably the “greenest” WRRF, with zero effluent discharge and wholly onsite biosolids use.

The narrative also sets the stage for understanding how Pennsylvania, producer of significant biosolids, is also a destination for biosolids from other states. The nature of Pennsylvania’s “accommodative” regulation of biosolids, and similarly restrictive rules in New Jersey, Delaware, and Maryland, ensures that the transport of biosolids regionally and in the direction of Pennsylvania is a significant part of the story of biosolids management regionally. This role is only indirectly revealed in the NBDP. That is because the survey was structured to discuss for each state the mass of biosolids production and the utilization outlets for those state-generated biosolids.

Though the NBDP is the latest information source available to us biosolids practitioners, in a way it is already outdated. Since the 2018 target year for data collection, pressures on two major categories, landfill disposal and land application, have increased. Important issue areas of PFAS contamination worries, risks of new regulations of soil phosphorus, and the experience of inadequate seasonal storage have underscored the challenges of maintaining farmland for biosolids applications. But landfill owners have tightened access by biosolids generators to municipal landfills. This is not only a challenge to Pennsylvania agencies, but more widely to agencies in adjoining states in the mid-Atlantic, which have been reliant on Pennsylvania destinations.

The other side of this “challenges” coin with biosolids in the MABA region is the opportunities for development of merchant facilities and innovative technologies. These include existing innovative facilities, such as regional composting (A&M Composting, Burlington Co-Composting and Rockland County Composting), thermal hydrolysis combined with mesophilic digestion (DC Water and HRSD), co-digestion plants (e.g., Hermitage Food Waste to Energy Facility) and drying processes (Synagro in Philadelphia and Baltimore). Indeed, the MABA region is a landing place for emerging thermal biosolids solutions, such as pyrolysis (BioForceTech), hydrothermal carbonization (SOMAX Bioenergy ), PA and gasification (EarthCare, EcoRemedy and Aries Clean Energy) -- solutions that seem to be particularly urgent in this time of PFAS.

The National Biosolids Data Project demonstrates that the mid-Atlantic region, responsible for nearly a quarter of the nation’s biosolids generation. It is your foundation for understanding future opportunities for biosolids management. Go use it: http://biosolidsdata.org. And, we who helped to assemble the database also will welcome corrections and updates as you find them worthwhile for keeping the information current and accurate, and you can do so by contacting Mary Firestone at [email protected].