MidAtlantic Biosolids Association

Biosolids News You Can Use

Large Sludge Composting Project May Be Coming to Butler

Butler, PA (2/16/20) - Tully Environmental presented a proposal to the Butler board to lease part of land in order to process sludge hauled from upstate from New York City. Treated sludge would be mixed with wood chips and other materials, then trucked elsewhere for use as compost. 

Biosolid Dryer Project Presented to Auburn City Council
Auburn, NY (2/14/20) - The Auburn City Council recently approved a new facility to handle solids from their waste management system. The council listened to a presentation on biosolids dryers where it was recommended they move forward with creating a new facility with sludge stabilization and sludge thickening processes. Presenters suggested that technology with the belief that it would provide the most risk control for cost increases related to disposal. 

Developers Abandon Plans for Controversial Sewage Sludge Plant in Slate Belt
Lehigh Valley, PA (2/3/2020) - “Synagro Technologies Inc. and Waste Management representatives have announced that they will no longer pursue building the proposed Slate Belt Heat Recovery Center. The plan was to build a plant that would convert sewage sludge into Class A biosolids that can be used as fertilizer or fuel. The drying process would have used heat generated by the Green Knight Economic Development Corp. energy plant at the landfill, which is owned by Waste Management.”
Sludge Recycler, Grand Central Landfill Pull Plug on Controversial Plant for Slate Belt

Bismarck Wastewater Treatment Plant Addresses Sludge Woes in Both Short Term and Long Term
Bismarck, ND (2/3/2020) - Bismarck Wastewater treatment plant typically applies biosolids to agricultural land between the time when all crops are harvested and the ground freezes. This year a wet fall delayed farmers in harvesting crops, so there was no window of time for biosolids land application. The facility rented a dewatering system to ensure they could empty and land apply their storage tanks. The city recently approved the purchase of dewatering equipment to avoid this problem in the future. 

Ohio EPA Issues New Permit to Wiles Storage Pond
Canaan Township, OH (2/7/20) - “The Ohio Environmental Protection Agency issued a permit to allow Class A (Exceptional Quality biosolids) and Class B biosolids from multiple National Pollutant Discharge Elimination System (NPDES) permitted facilities to be stored in the Wiles Storage Pond, located just east of the Friendsville Road and East Pleasant Home Road intersection, and owned by Pleasant Home Farm LLC.”

Fellsmere Extends Biosolids Ban Through August
Fellsmere, FL (2/7/20) - Fellsmere recently extended its biosolids moratorium another 180 days. This agricultural community first approved a moratorium in August of 2018 and has repeatedly extended the moratorium. 

Why Recycled Cleaning Products Are The Next Step In The Green Revolution
reNEW Technologies (2/10/20) - “CYCLE manufactures everyday household cleaning products – such as a toilet bowl cleaner, bathroom cleaner, and all-purpose cleaner – from nothing but all-natural soap, citric acid, oil-based fragrance, derived organic acids, pure water and wastewater. The base of CYCLE products is, in fact, one of the byproducts of biological wastewater treatment facilities, known as biosolids.”

You poop. You flush. Here’s What Tampa Bay Does with Your Wastewater
Tampa, FL (2/10/20) - This article gives an overview of the South Cross Bayou Advanced Water Reclamation Facility treatment process. Twenty two million gallons flow through the facility on an average day and the treated water is used to irrigate lawns and parks while the solid waste is processed into 6,000 tons of pellet fertilizer annually. 

Synagro Awarded City of Fort Worth Contract to Design-Permit-and-Construct Drum Drying Facility
Fort Worth, TX (2/11/20) - City of Fort Worth has partnered with Synagro of Texas-CDR (Synagro) to provide a long-term solution to its biosolids management needs. Commencing in April of 2020, Synagro will assume operation of the city's current biosolids management facility and program and will work with other project team members to design-permit-and-construct the drum drying facility, which Synagro will operate for up to twenty years.

Free compost giveaway by the City of Fortuna beginning Monday, Feb. 24
Fortuna, CA (2/12/20) - “The City of Fortuna is planning to host a promotional giveaway for Exceptional Quality (EQ) Class A compost for beneficial reuse as a soil amendment to your property or place of residence beginning Monday, Feb. 24 until Friday, Feb. 28.”

Oxford Seeking Grants to Deal with Treatment Plant Sludge
Oxford, ME (2/14/20) - Until last year, Oxford produced and sold sludge to Lewiston. Federal and state regulations related to PFAS have put an end to Oxford selling its sludge to Lewiston, so the town has started storing its processed sludge. A study commissioned last year by the city and performed by Woodard & Curran, an environmental consulting firm in Portland, has recommended the city begin dewatering sludge before it is transported for disposal.

Holland Planners Approve Giant Sludge Digester
Holland, MI (2/13/20) - The Holland Planning Commission recently approved plans to construct a 102-foot-tall anaerobic digester at the Holland Area Water Reclamation Facility.

ADEM Moves to Regulate the Dumping of "Sewer Sludge" on Alabama Farmland
Montgomery AL (2/14/20) - “New standards for the "beneficial use of by-product materials for the purpose of land application" passed unanimously at Friday's Alabama Environmental Management Commission meeting.” The new regulations are said to allow the Alabama Department of Environmental Management to regulate the transportation of the sludge and how much is applied to the land. There will also be required buffer zones.

Sewage Sludge Could be Spreading Microplastics, Report Warns
United Kingdom (2/4/20) - A 2017 report from the UK’s Environmental Agency has raised concerns after it was recently released. The report suggests that biosolids may be contaminating farmland with microplastics, metals and organic pollutants. The Environmental Agency is planning to release a sludge strategy report later this year that will find solutions to sludge pollution and how toxins can be removed from the UK's natural environment and identify waste recovery activities that reduce our dependence on manufactured fertilisers.

Elamkulam Plant Finding It Hard to Shed Its Dry-Sewage Manur
Kochi, India (2/7/20) - Elamkulam treatment plant in India has been processing sewage sludge to be used as fertilizer, but for the past 5 - 10 years no farmers have been interested in purchasing the material. 

Study: Adding Sewage Sludge to Soils Does Not Promote Antibiotic Resistance
University of Gothenburg, Sweden (2/10/20) - “Researchers from the Centre for Antibiotic Resistance Research, CARe, at the University of Gothenburg investigated effects of over 30 years of regular spread of sludge to soils.” "The overall result is that virtually nothing happens. Everything we studied looks about the same in the different soils, regardless if a lot of sludge, little sludge, no sludge or just inorganic fertilizers were added. No antibiotics accumulated in the soil, nor did any resistant bacteria. The only clear thing we can see is that the nutrient supply affects which bacterial species thrive best in the soils," said Joakim Larsson, the professor leading the research group.


Biosolids Science and Environmental Catastrophism
By Bill Toffey

I blame the Amazon gift card and Amazon app on my iPhone. Together, they make my impulsive purchase of another book of environmental catastrophism far too easy. I was primed for this purchase by the sense of dread from reading on my cellphone the NY Times environmental news briefing. The story What Was Said at Davos on Climate Change, led to How trees could help to save the climate, and then to the discouraging why tree planting is a bad idea. So, when I was presented with a push notification for Climate Leviathan, my mindless, fear-based reaction was to perform an Amazon “one-click” and the next day the book was at my door.  I started in:  “The political problems we face cannot be fixed by simply delivering science to the masses.” Well, yes, science may be an inadequate tool for overcoming the growing sense of environmental catastrophe, but without science, we are lost, right??!

I had just revisited my article in NYWEA’s winter 2019 ClearWaters magazine, “Biosolids: Understanding the Invisible Evils that Keep Us Awake.” The magazine also well covers the “numero uno” cause of biosolids catastrophism, namely polyfluoroalkyl substances (PFAS), a class of compounds present everywhere, but also in biosolids. My noble aspiration was to prove that, even with so fearsome an opponent as PFAS, soil processes, when combined with our wastewater treatment system, can be an effective barrier to the flow of so many of society’s TOrCs, or toxic organic chemicals.

As for PFAS, science shows us that loadings of PFAS to wastewater plants and the consequent concentration levels in most biosolids are low (Mass Loading and Fate of Perfluoroalkyl Surfactants in Wastewater Treatment Plants  ), below levels constituting a risk. But even at the relatively low concentrations present in biosolids, PFAS can leach from biosolids and arguably contribute to existing PFAS loads in the groundwater.  See these articles:  Loss and in situ production of perfluoroalkyl chemicals in outdoor biosolids–soil mesocosms and Environmental risk assessment of perfluoroalkyl substances and halogenated flame retardants released from biosolids-amended soils.  Research has shown uptake into plants and animals.  See, for example, Uptake of perfluoroalkyl substances and halogenated flame retardants by crop plants grown in biosolids-amended soils and  Bioaccumulation of emerging organic compounds (perfluoroalkyl substances and halogenated flame retardants) by earthworm in biosolid amended soils). Biosolids-specific research on PFAS is arguably incomplete, and environmental catastrophism generates the political pressure to take regulatory action even without science.

Could it be that PFAS in biosolids is just one more of the biosolids pollution “fads” we have witnessed over the years?  When I checked in with Ned Beecher, our biosolids protector in the field of PFAS, he suggested that, as a broad awareness of PFAS had begun to consume society, the focus on biosolids has, too, somewhat subsided. For the time being, public concern for PFAS has, in a way, “sucked the air out of the room” for consideration of other contaminants.

I had this thought.  While the spotlight is on PFAS as an environmental catastrophe, ought biosolids practitioners strive to get ahead with research on other biosolids-borne TOrCs, and their impacts on soils and crops?  I reviewed the eminent 2010 report Trace Organic Chemicals in Biosolids-Amended Soils: State-of-the-Science Review (WERF Report SRSK5T09). In italics, in the final chapter, the report concluded: “Very few studies were identified that were intentionally designed to address the fate, transport, bioaccumulation, and toxicity of TOrCs in biosolids-amended soils under well-controlled conditions. The most significant data gap, however, is the absence of human toxicological and ecotoxicological data as well as biotransfer data for ecological receptors.”

When I went to my favorite science source, Google Scholar, I could find few articles that demonstrate that our profession took up this recommendation in any serious way. When it came to the environmental fate of PPCPs (pharmaceutical and personal care products), for instance, the number of research papers that have been published globally around biosolids and PPCPs has pretty much flat-lined over the decade at about 300. One science colleague observed: “the general hysteria on that front is gradually subsiding… There has also been a general recognition that potential for human harm is nonexistent.”

Still there has been progress. Over the decade since 2010 report, a few of the notorious, persistent TOrCs have been given additional study. These include compounds such as triclocarban (Fate of triclocarban in agricultural soils after biosolid applications), PCBs ( Four decades since the ban, old urban wastewater treatment plant remains a dominant source of PCBs to the environment), and polybrominated diphenyl ethers (PBDEs) (Polybrominated diphenyl ethers: Residence time in soils receiving biosolids application).   

We have also had research into the fate of soil-applied antibiotics. The article Risk assessment of biosolids-borne ciprofloxacin and azithromycin found “negligible human and ecological health risks from biosolids-borne CIP and AZ under real-world biosolids application scenarios.”  Research with similar approaches was reported in  Rapid and complete degradation of diclofenac by native soil microorganisms and, for fluroquinolones,  Dissipation of antibiotics in three different agricultural soils after repeated application of biosolids.

The interest in environmental fate of antibiotics has a corollary with another emerging area for biosolids research. That is “ARG,” or antibiotic resistances genes. This is the genetic material fragments from bacteria exposed to antibiotics, and the human health concern is for the potential for spread of resistance genes among human pathogens. To date, biosolids-borne ARGs seem to be highly vulnerable to the treatment by anaerobic digestion followed by aerated soil microbiome and are readily degraded, but others believe the risk is significant. This is shown in the report: The potential implications of reclaimed wastewater reuse for irrigation on the agricultural environment: The knowns and unknowns of the fate of antibiotics and antibiotic resistant bacteria and resistance genes – A review. 

Another new issue for biosolids research is plastic pollution. Plastic production since the 1960s has resulted in release of plastics to the global environment, lands, streams and oceans, in large fragments down to nano-scale particles. For a chilling review of the extent of pollution, the 2017 report Production, use, and fate of all plastics ever made is a “must read.”  Microscopic sized plastic beads and fibers are released to wastewater via consumer products and clothes washing (Microfiber release from different fabrics during washing), and, when biosolids is land applied to farm soil, biosolids-borne microplastic become part of the soil-plant system. Thereby, biosolids is one of several sources of plastic contamination that is now routinely incorporated in farm soils (An overview of microplastic and nanoplastic pollution in agroecosystems). The effects of macro- and micro- plastics in the soil-plant system in agriculture are the subject to a blossoming of research, but the effects on soil properties and animal and plant life are still being worked out (Current research trends on plastic pollution and ecological impacts on the soil ecosystem: A review). Whether biosolids-borne plastics is a significant problem for soil health is a matter of dispute, but one that warrants our attention (e.g., Are Agricultural Soils Dumps for Microplastics of Urban Origin?), lest this issue be cast in the light of environmental catastrophism.

Of greater risk than microplastics or the latest TOrC horror to our profession is that we underfund biosolids research into the very great counterbalancing benefits of biosolids, particularly the multiple aspects of recycled nutrients and organic matter supplementation. An example of the importance of making the case for biosolids is the 2019 report out of Sweden, a country which in the past has been an origin of precautionary fears of biosolids. The European Sustainable Phosphorus Platform reported that in late January a key report was issued, the  Sweden Enquiry recommends use of sewage sludge on crops. This report, Hållbar slamhantering, strongly supported land application of biosolids for its recycled phosphorus content. While the report is in Swedish, its English summary chapter concluded: “Evidence for a total ban being necessary is lacking, however, research having failed to prove that crops grown with sludge have health impacts or have an adverse impact on ecosystems in agriculture. On the other hand, there is clear evidence that sludge fertiliser application supplies plant nutrients and humus that agriculture demands.” This is a great statement, and ought to substantially address the catastrophism that has surrounded Swedish biosolids programs.

In the end, repeated confirmation of no impacts of TOrCs on soil health and plant growth, and the compelling evidence of vibrant crop production under treatments with biosolids, can win the day.  Giving into catastrophism may well trigger an impulsive “one-click” type decision, whether to buy a book or to pass legislation banning biosolids.  But we need to remind ourselves that biosolids research delving into the fate of TOrCs and demonstrating soil and crop benefits of biosolids together are the best salve for pitfall of biosolids catastrophism. The risk that we fail to make a scientific case that the resource benefits of biosolids far outweigh the risks of TOrCs would be the true catastrophe.


Symposiums & Presentations

2019 Summer Symposium

2018 Annual Meeting & Symposium

2018 Summer Symposium

2017 Annual Meeting & Symposium

2017 Summer Symposium

2017 NJWEA Workshop

2016 Annual Meeting & Symposium

2016 Summer Symposium

2016 NJWEA Workshop


BEAM 2.0 and N2O
by Sally Brown

It has been 10 years since the BEAM model came out.  No, BEAM is not some type of electronic vehicle.  That would be the LEAF model.  This is the model that Sylvis Environmental Services in British Columbia developed for the Canadian government to quantify the carbon costs and benefits associated with different biosolids process and end use/ disposal practices :https://www.ccme.ca/files/Resources/waste/biosolids/beam_user_guide_1430.pdf).

I helped out with that model, as did Ned Beecher and Andrew Carpenter of North East Biosolids and Residuals Association.  We three also wrote a paper about the model that was published in Environmental Science & Technology.  I am happy to send that along, but the focus of the library for the next few months will be on publications that have come out since then.  Just like the 503 regulations, the BEAM model can stand to be looked at over time to see what type of updates and revisions might be available.  The focus for this library is nitrous oxide (N2O) emissions from land application.

N2O is tricky. It is hard to find but can appear in big spikes.  A little goes a very long way.  With a CO2 equivalent of 296x to 310x, small amounts of N2O can add up very quickly in a green house gas calculation of CO2 equivalents.

Here is a quick review on N2O formation.  N2O is formed in one of two parts of the nitrogen cycle.  It can be produced as NH3+ (ammonia) is converted to NO3- (nitrate) or when NO3- is converted to N2 gas.  In both cases, it is made by accident, as an incomplete microbial transformation.  There is consensus that most of the N2O is formed as nitrate is converted to nitrogen gas.  This process is called denitrification.  It happens when microbes are eating carbon and they need a place to put electrons.  They eat the carbon for the energy stored in the carbon compounds, just the same as we do.  If you look at that label for Cheetos (a vice that I am proud to say I’ve conquered) you can see the calorie count. 

When we eat food, the calories are a measure of the energy contained in the fixed carbon.  When we release the energy, we also release electrons.  Those go to turn carbon into CO2.  For the microbe eating the soil equivalent of a Cheeto they also go to CO2- unless there isn’t enough oxygen around.  In that case they get stuck on NO3. Sticking electrons on NO3 to make N2 gas is a multi-stage process.  N2O is formed at one of those stages.  If the reaction goes to completion you get N2 gas.  No big deal, no carbon impact.  It is when the N2O is left as is that you get the big impact.

Diagram of N2O formation from Sullivan et al. (2013)

The take home message is this.  For N2O to be formed, you need low oxygen concentrations and a carbon source for microbes. 

The IPCC default factor for N2O emissions is 1% of the total N applied.  In the original BEAM model, we had different factors for N2O emission based on soil texture and whether the biosolids were dried.  We assumed emissions of 0.5% total N for coarse textured soils and 2.3% of total N for fine textured soils.  These factors were reduced by 50% when the biosolids solids content was > 80% for fine textured soils.

So, what has 10 years brought?  The first article in the library is a survey paper on N2O emissions from soils that have received organic amendments.  One of the authors here is Philippe Rochette.  Dr. Rochette works for Ag Canada and is a recognized and reasonable expert on this topic.  The authors surveyed all of the peer review papers on this topic to come up with revised values for default emission factors.  They ended up finding 38 usable studies that were done in 12 countries.  The overall N2O emissions factor across all organic amendments included was 0.57±0.3% of total N, lower than the IPCC factor of 1 for synthetic fertilizers.  They also found that emissions varied based on type of amendment and type of soil to which it was applied.  The three types of amendments were:

High risk (1.21 ± 0.14%)
  • Animal slurries
  • Waste waters
  • Biosolids
Medium risk (0.35 ± 0.13%)
  • Solid manure
  • Compost + fertilizer
  • Crop residues + fertilizer
Low risk (0.02± 0.13%)
  • Compost
  • Crop residues
  • Paper mill sludge and pellets

They found higher emissions when amendments were added with fertilizer and also a 2.8x increase in emissions when materials were applied to finer textured soils. 

If you look at the study in greater depth you notice a few things.  There are very few biosolids studies; the references that I saw were only for biosolids added with fertilizers.  So, the default value for biosolids is not useful.  Also not clear when the authors say ‘biosolids’ they are referring to municipal wastewater solids.  The 4th paper (author overlap) defines biosolids very broadly as including animal solids and pulp and paper residuals.  Also telling was the information on pig slurry.  Pig slurry with >10% N, 5% solids, a C:N ratio <5 had higher emissions than animal slurries with solids contents >5% or more stable products (C:N ratio >30).  The authors say “…pig slurry contains high amounts of NH4 and easily decomposable organic C that can, in concert, directly stimulate soil denitrifers… thereby further stimulating N2O production through denitrification’.”  Cow manure, with more stable C compounds had lower emissions than pig slurry.  They found that if mineral N (NO3 and NH3) were less than 0.3% dry weight emissions were lower.  We can use that to make some small refinements to BEAM based on biosolids characteristics.  Looking over the data set they found C:N ratio >21 would not increase N2O emissions.  More rain led to greater emissions and higher organic matter in the soil resulted in a small increase in emissions.  Again, some ways to refine the BEAM model. 

The second paper is also from Rochette.  It presents results from a field study in Canada where different types of animal manures were applied to a sandy and a clayey soil.  In Table 3 you see that the liquid swine manure (LSM) released 7.6 kg N2O per ha-1 in the silty clay soil and 0.5 kg N2O per ha-1 in the sandy loam for N2O emissions factors of 4.8% and 0.1%, respectively.  Emissions were concentrated in the spring and fall when moisture content of the soils was highest.

The third paper takes us to Brazil, to a reforestation study where biosolids and biosolids compost were applied to a degraded pasture.  The biosolids had been aerobically stabilized and the compost was produced with biosolids mixed with wood waste.  Application rates were low.  Gas samples were collected over time with no replication across plots.  The soil was an Ultisol, a well weathered soil.  These are typically high in clay, but texture wasn’t reported.  The compost had the highest emissions (2.11%), with biosolids coming in second (0.94%).  So, both are lower than what Rochette saw in the high clay soil. 

The fourth paper takes us back to Rochette and back to Canada.  This paper was published more recently (2018) than the first two from Rochette.  Like the first paper, it also presents a compilation of results from other studies rather than original research.  The authors found that high precipitation and fine soil texture were significant factors.  They also found that biosolids derived N (with biosolids here defined as : ‘Sources of the biosolid organic N in this study included aerobically digested pig slurry, de-inking paper sludge, filtered pig slurry, anaerobically digested and flocculated pig slurry, and mixed primary and secondary paper pulp sludge’) behaved differently and, as a result, were analyzed separately.  Here the authors did a stepwise regression, seeing what factors were responsible for N2O emissions.  For synthetic fertilizers, precipitation was responsible for 38% of the variation observed in the data; the higher rain meant more anaerobic conditions, higher rates of denitrification and more N2O.  Amount of N applied took care of another 15% of the variability.  More N resulted in more N2O.  Sand content decreased emissions as did higher pH (this has to do with microbial denitrification pathways).  These variables were able to account for 70% of the variability in the data.  For organic sources of N, the process was simpler.  About 62% of the variability in the data was explained by soil texture, with another 20% depending on whether it was an annual or perennial system (perennial systems have lower emissions).  Here is the take home in terms of emissions factors:

Emissions in Western CA were much lower likely due to lower rainfall and higher pH soils:

From here we move to the last paper in the library, this one directly compares different types of animal waste application to control and synthetic nitrogen in clayey soils in Canada.  Raw pig manure as well as stabilized pig manure and paper sludges were land applied.  The treated manures and the pulp sludges are referred to as biosolids.  There is a high probability that the behavior of these materials is similar to the behavior of the stuff that we call biosolids.  The emissions factor for raw pig slurry was 2.5, with a decrease to 1.6 after the material had been through an anaerobic digestor.   This and the first paper in the library are the two take homes as far as I am concerned., and number 4 as well, but talk about a dense read!  My brain was giving off N2O after that one.

So, we have had some progress after 10 years.  We can adjust BEAM further for soil texture, rainfall and type of crop.  We can say with more certainty that drier, digested materials and composts emit lower amounts of N2O than wet, raw slurries.  We walk the BEAM step by step.