Biosolids Dust: An important attribute in biosolids marketability

 Dust is a big deal! Viruses have so commanded the front stage of our news media that you may have missed other big “dust” stories. China is having a BIG dust problem. The article “Apocalyptic skies as Beijing hit by worst sandstorm in a decade” (March 15, 2021) explains winds off Mongolia are carrying a dense cloud of dust to Beijing. This is an issue with serious health and environmental implications (Characterization of the composition of dust fallout and identification of dust sources in arid and semiarid North China. The newspapers are happy to remind us that early Spring brings tree pollen, a phenomenon steeped in science  Pollen calendars and maps of allergenic pollen in North America.  Two weeks of dry weather in the mid-Atlantic, and wildfires are releasing unhealthy soot: “Wildland firefighter smoke exposure and risk of lung cancer and cardiovascular disease mortality.” While the dangers of dust-borne lead in homes is well established (Children’s Lead Exposure: A Multimedia Modeling Analysis to Guide Public Health Decision-Making), household dust contains many more compounds of concern, many of which we see also in our wastewater and biosolids, such as flame retardants and phthalates: Tracing the chemistry of household dust The sloughing skin that joins cloth fibers in the household dust. Worse yet, some of the dust may be radioactive (Health Implications of Fallout from Nuclear Weapons Testing through 1961). On a lighter note, we also learned in a January 2021 news article that amidst the load of anthropogenic dust, which has greatly accumulated in my house during the pandemic lockdown, is some very ancient dust (7 billion-year-old stardust is oldest material found on Earth), older than our solar system. Yes, dust is a big deal for scientists, inhabitants, and life in the world.

Dust is also important for us biosolids practitioners, too, but you would not know that from the paucity of professional news coverage and research on the topic.  The Water Environment Federation has brought into its website all papers and articles from several decades of conferences and publications.  These are found in Access Water. In this large database, 4,660 articles on biosolids are catalogued. While some 700 articles mention biosolids dust when dealing with treatment plant processes, to protect from fire, explosion and worker injury, only two papers treat dust as a key characteristic of biosolids products deserving consideration in the choice of treatment processes.  The first paper, from the 2017 WEF Residuals and Biosolids Conference, is  Not All Dryer Products are Created Equal, and the second is from WEFTEC 2019,  Worthless Dust or Valuable Resource? Drying Thermally Hydrolyzed Solids the Right Way.

The first paper, by Material Matter’s Lisa Challenger, makes the case for a eyes-wide-open approach to selecting technology for the desired end-use of the product. Challenger underscores the point that technologies identical in terms of Part 503 regulatory compliance (Pathogen Reduction PFRP Class A – Alternative 5 and Vector Attraction Reduction – Option 8) yield end products that are opposites in their suitability for distribution and marketing. The marketable heat-dried biosolids was a digested biosolids processed in a rotary kiln direct dryer and the non-marketable dried biosolids was an undigested biosolids dried in an indirect paddle-type dryer. In the second case, high dust, low density, and intense odors doomed the product’s use as a fertilizer, despite regulatory compliance with national standards.

The second paper, by HDR’s Stephanie Spalding and Sebastian Smoot, examines three attributes of biosolids product quality -- energy content, friability, and bulk density -- against various combinations of equipment and process trains and of user requirements. Too few case studies permitted the authors conclusive answers, but several themes were suggested by nine cases, and dustiness of the product was a key concern. High dustiness followed several process features: thermal hydrolysis of the entire solids flow, the use of iron as a coagulant, a drying process that agitated the solids, and post-treatment handling by truck and land application equipment. One or more of these features could yield dust that discouraged customer acceptance. 

Dust in biosolids products may be a problem for a variety of reasons, but human health effects are primary. If there were a “canary in the coal mine” for risks from biosolids dust exposure it would be treatment plant operators. I had not held much concern, ever since the Philadelphia Water Department was one of 4 compost facilities in a NIOSH health study. This lead to  “Respiratory Exposure Hazards in Composting” which determined: “Very high levels of dust, endotoxins, (1-3)-β -D-glucan and ammonia were measured in compost facilities depending on the location, activity and enclosure. Exposure appeared to be correlated with few respiratory health parameters, although no significant objective pulmonary function differences were detected between the study groups.” I drew from this the premature conclusion that community exposure to biosolids compost dust would be benign.

Since that workplace study of the late 1990s, new tools have become available for measuring and characterizing “dust.” Researchers have sharpened their understanding of the characteristics of airborne biological particles, especially with genomic tools for identifying microbes.  Dust of the kind from biosolids is more specifically defined as a bioaerosol:  “microbial fragments, constituents of cells and airborne biological particles that can consist of fungi, bacteria, pollen, fragments, constituents, particulate matter (PM10), and by-products of cells, that may be viable or nonviable.” 

Current research shows that organic waste treatment can be a significant source of bioaerosol exposures. The article Methods for Bioaerosol Characterization: Limits and Perspectives for Human Health Risk Assessment in Organic Waste Treatment describes “composting biomarkers” for identifying a “causality process between chronic bioaerosol exposure and disease onset, and finally, on defining common exposure limits.” Advances in microbiology expands the range of microbes exposures associated with wastewater treatment (Evaluation of Bioaerosol Bacterial Components of a Wastewater Treatment Plant Through an Integrate Approach and In Vivo Assessment): “next generation sequencing analysis was used also to identify the uncultivable species that were not detected by the culture dependent-method.” As new measurement tools are added, the range of potential risks seems to enlarge. In The size distribution of airborne bacteria and human pathogenic bacteria in a commercial composting plant “Seven out of eight HPB [human pathogenic bacteria] with a small geometric mean aerodynamic diameter had a high concentration in composting areas.”

Yet, while tools for measurement have improved, the attribution of risk levels has lagged. In Bioaerosol exposure from composting facilities and health outcomes in workers and in the community: A systematic review update the authors conclude “there is insufficient evidence to provide a quantitative comment on the risk to nearby residents from exposure to compost bioaerosols.” This kind of open issue is itself an issue, particularly from the viewpoint of environmental justice. The article Characterising populations living close to intensive farming and composting facilities in England observes that with regard to high exposures to bioaerosols from intensive farming “few people (0.01 %) live very close to these sites and tend to be older people. Close to composting facilities, populations are more likely to be urban and more deprived.” The key here is that science is in the early stages of exploring the human health risks of bioaerosols.

Low dust is a prized attribute of heat-dried biosolids pellets. In the WEF Conference paper Toronto’s Pelletizer Facility – A New Start, the “new start” included the aspiration that “dust production, resulting from friction during transport and handling, will be very low with the biosolids pellet product.”  To this attribute was also that of hardness: “pellet hardness is… slightly higher than that of chemical fertilizers… [such that] handling and spreading of the product is relatively easy and dust-free.”

While durability and dustiness are key attributes, no article in WEF Access Water discuss measurements of these attributes. Chemical fertilizer and wood pellet industries are keen to prevent pellets from turning to dust, a property they term durability. Hence, these industries deploy a “product durability index” and measure this with “product durability testers.” The PDI is “a standardized parameter for specifying the ability of the fuel pellets to resist degradation caused by shipping and handling.” For, under $4,000 you, too, can own a “Two Compartment Pellet Durability Tester.”  This tester subjects pellets to a tumbler that simulates conveyance and transport handling, and test results are reported as a percentage of pellet mass that degrades into dusty particles. This sounds as though this device ought to have a place in measuring durability and dryness of biosolids pellets, but it does not.

Though durability and dustiness seem to be secondary objectives in choice of treatment technologies, various pre-drying and post-drying options at the plant can modify these product attributes. Fine screening and digestion are treatment steps that reduce fibers and low-density organic matter, and subsequent dried product is denser than undigested biosolids. Post-drying screening is another step, and Challenger reports: “screenings are recycled back to the head of the dryer and blended with the cake product to avoid the “sticky” phase of the biosolids product typically returning and blending fine particles into the cake feeding the dryers, results in a denser product. “ 

What is more, the world stands ready to help with durability and dustiness. Many manufacturers provide granulators that could help us create a durable pellet, such as a Compost Pellet Machines and a Powder Granulator Machines; you can even buy on Amazon a Feed Pellet Machine. Though granulated products may still be dusty and odorous, you can add to it a coating.  Surface Chemists of Florida can customize a coating for dried biosolids; its SurPhase FLOW promises to “preserve your product’s integrity.” Similarly, ArrMaz can design a special DUSTROL® or GALORYL® dust control coating for biosolids.  Yet, these machines and coatings are an on-going expense to fix a situation that might have been otherwise avoided with better technology selection upfront.

The matter of control of biosolids dust is no light matter. Biosolids products that lack durability, that fail to withstand transport and land spreading and that consequently pose a risk of bioaerosol release are unlikely to be part of an economical, sustainable program. Each component of treatment, from screening, to digestion, to dewatering, to subsequent stabilization, warrants evaluation for its contribution to the “product’s integrity.” Just as the SARS-CoV-2 virus has raised global fears about invisible particles in the air we breathe, our industry cannot afford to be a source of invisible particles that raise public fears.  We ought to recalibrate our focus on technologies that minimize dust and bioaerosol releases in response to new health concerns and scientific capabilities, because Biosolids Dust is a Big Deal.   

Biosolids Boost to Productivity: Is biosolids a "multivitamin for the soil"?

 

They [farmers on Eastern Shore of Maryland] put in an order for pellets because they hear it keeps deer away from the beans, but they make a second order because they see a difference. I am not sure what it is, but it might be micronutrients.”  I was asking Synagro’s Steve McMahon about the aspects of dried biosolids that “sell.” This was not the first time I had heard these “pitches:” pellets are a deer repellent; pellets are like a vitamin pill for the soil. Are either of these aspects of biosolids true?

As we are experiencing with COVID-19 and with presidential politics, the lies we tell ourselves and the truths we hold as “self-evident” are hard to dig into. Can science help us avoid unexamined biases we hold and the lies we tell ourselves? With respect to biosolids, can science tell us if biosolids pellets repel deer and if biosolids are a vitamin for the soil?

Fascinatingly, even though billions of people are concerned with nutrition and many hundred thousand scientists attend to human and environmental health issues, clear irrefutable answers to basic questions are in short supply. Can there be any surprise, then, that clear irrefutable answers on biosolids are also in short supply?

Issue of human health remain controversial, and how science works to clarify these issues is a metaphor for how we use science to demonstrate the benefits of biosolids.

Isn’t it true that vitamins for the human body are good? Science is mostly NO, not supporting multi-vitamins.  “There is no indication that supplementation is necessary for healthy, non-pregnant, non-lactating adults” according to a 2019 review article Minimal Purposes of Multivitamins. Science supports Vitamin D for people without sun exposure, iron for women of child-bearing age, and folic acid for pregnant women, but almost nothing else. “Essential minerals,” like zinc, seem unsupported as necessary supplements. So, can we be sure biosolids as vitamin are necessarily good?

Is it true that foods labeled organic are more nutritious than conventional foods? The science is mixed, YES and NO. One review article (A literature‐based comparison of nutrient and contaminant contents between organic and conventional vegetables and potatoes) says, sometimes yes, sometimes no, but “it becomes difficult to justify general claims indicating a surplus value of organic over conventional vegetables and potatoes.” So, can we be sure the “organic” label would connote better nutrition.

Is it true that a wholly plant-based diet confers greater health than a meat-eating diet? The science is not clear, and mostly NO. A major study (Nutrition and Health – The Association between Eating Behavior and Various Health Parameters: A Matched Sample Study) out of Austria suggests that vegetarians are less healthy overall than folks eating conventionally. So, can we be sure biosolids users deploy biosolids for the right reasons?

Is it true that bacon is no good!? The scientific evidence is YES (Aw, say it is not true!). The 2020 review article Red and Processed Meats and Health Risks: How Strong Is the Evidence?  says“…dietary guidelines should continue to emphasize dietary patterns low in red and processed meats and high in minimally processed plant foods such as fruits and vegetables, whole grains, nuts, and legumes.” So, can we be sure biosolids is always good for soil, particularly considering pH changes, high phosphorus and low potassium.

Is it true that vegetarianism is better for the planet? The answer is YES, BUT. As the commentary “Why the debate between vegans and meat-eaters is pointless” says “it is a complex question exactly what kind of food system would be ideal… Keep an open mind.” So, are biosolids nutrients, contributing to the circular economy, infallibly preferred to fossilized sources?

Isn’t it true that avoiding GMOs makes a difference in a person’s health?  Again, the science is not clear.  As one large German study (Republished study: long-term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize) concluded: “Our findings imply that long-term (2 year) feeding trials need to be conducted to thoroughly evaluate the safety of GM foods and pesticides in their full commercial formulations.” So, are the organic micropollutants added to soil with biosolids clearly without risks?

Science cannot give us firm answers to such huge questions of human and environmental health. What can we expect of the answers about the safety and effectiveness of biosolids as a fertilizer, as a vitamin for soils that deters deer?

Are biosolids safe to use? The answer is a firm YES, at least as firm a conclusion as scientists are apt to make. My original “go-to” document is the iconic 2005 journal article Sustainable land application: An overview. No less significant is the 2002 WERF report Evaluating risks and benefits of soil amendments used in agriculture,” with its many hundreds of journal citations. But nothing quite rises to the most current resource than the collective response by soil scientists in the W4170 group, in its technical answers to the EPA OIG Report. The OIG “Report: EPA Unable to Assess the Impact of Hundreds of Unregulated Pollutants in Land-Applied Biosolids on Human Health and the Environment” was regarded as ill-informed and misleading by scientists familiar with the original regulatory development. Their response was brought together in the release of W4170 Multistate Research Committee Response to USEPA OIG Report No. 19-P-0002. The elements and compounds for which research into risks is warranted are countable on two hands.

Are agricultural soils in need of micronutrient supplementation? Science suggests the answer generally is NO. But this is a complicated question, and scientific answers require more resources of time and money than usually available.  One article that underscores this is Effects of Nutrient Antagonism and Synergism on Yield and Fertilizer Use Efficiency. This study starts out “great potential to increase the nutrient use efficiency, and consequently, yield levels by considering all essential plant nutrients (macronutrients N, P, K, Ca, Mg, and S and micronutrients Cl, Fe, B, Mn, Zn, Cu, Mo, and Ni) in fertilizer products and fertilization strategies.” The authors point out that “Studies about the effects of an annual fertilization with micronutrients to compensate for the removal by crop are rare.” Yet they hold the point of view that “balancing the composition, amount, timing, and mode of delivery of fertilizers to plants and soil, thereby aiming to overcome antagonism and stimulate synergism.” Does biosolids accomplish this balancing?

Can the balance of nutrients in soil affect the nutrient quality of the crops growing on them?  The answer seems to be YES. This area of scientific inquiry stands as its own discipline. A publication on this topic is Fertilizing Crops to Improve Human Health: a Scientific Review.  The conclusion of this report is “Fertilizer contributes to both the quantity and quality of the food produced. Used in the right way-applying the right source at the right rate, time and place-and on the right crops, it contributes immensely to the health and well-being of humanity.”

Do the micronutrients in biosolids impart a natural balance of micronutrients to the soil? The answer is “LIKELY YES.” The abundance and order of nutrient concentrations in biosolids mirrors that of the concentrations in plant tissues. This can be seen by lining up in rank order the essential nutrients for plant growth (K>N>Ca>S>Cl>P>Mg>Mn>Fe>Zn>Cu>B >Ni [Source: Plant nutrient functions and deficiency and toxicity symptom]) against the abundance and order of micronutrients in biosolids (Ca>N>P>Fe>Mg>Mn>K>Zn>Cu>B>Mo>Ni [derived from Targeted National Sewage Sludge Surveys). The primary outlier is potassium (K). Because K is a very soluble cation, it passes out in wastewater effluent rather than attach well to biosolids organic matter.  Biosolids concentrations better mirror plant tissue concentrations than soil concentrations.  Soil micronutrients loadings do not reflect micronutrient availability to crop roots  Vegetable crop scientist George Antonious demonstrates this fact in Elevated concentrations of trace elements in soil do not necessarily reflect metals available to plants.

Can the micronutrients in biosolids boost the yield and nutrient content of crops? The answer is LIKELY NO. I checked in with several of the scientists who worked on the W4170 report. First, most crops are not subject to deficiencies in micronutrients, so additions through biosolids will not register an effect.  Second, the vast majority of farmers we would be working with are among the top producers by design of our programs, with implemented nutrient management and conservation plans, with soils adjusted for proper soil pH, and with established soil metals test results. One of our science friends said a farmer once provided anecdotal testimonial to a zinc deficiency corrected by biosolids. Another researcher had worked on a coarse-textured, iron-deficient soil, and biosolids had demonstrated yield benefits. Another scientist cautioned about the opposite concern; deficiencies of Zn, Mn and Cu could be induced by lime-stabilized biosolids. But, in general, crop yield increases from the micronutrients contained in biosolids are not a “thing.”

Can biosolids be the basis for repairing soils with a demonstrably damaged balance of nutrients? The answer is YES. Iconic work by Rufus Chaney and Sally Brown showed how biosolids products repaired mine sites and damaged urban soils ( In situ soil treatments to reduce the phyto- and bioavailability of lead, zinc, and cadmium, Greening a Steel Mill Slag Brownfield with Biosolids and Sediments: A Case Study, and Biosolids Products for Urban Agriculture). What is more, biosolids enable poor soils to sustain economically valuable production, as in biofuel crops (Sylvis to support green coal mine reclamation project in Alberta).

The question of real importance:  can biosolids repel deer? Most likely YES!  The evidence is not just anecdotal. First, Milorganite stands behind this benefit of its dried biosolids product. It posts several “science” articles in its support (e.g., Using Milorganite® to temporarily repel white-tailed deer from food plots). Various professional columnists (e.g., Gardens All) and technical bodies (e.g., University of Georgia Extension) recommend use of Milorganite as deer repellant.

That is good enough for me. Certain lifestyle choices and biases are best held as faith, clear and true, rather than subjected to scientific scrutiny, incomplete and messy. My breakfast will continue to embrace blueberries and granola, full of antioxidants and fiber, and I will continue to have faith in biosolids as a “multivitamin for soil.”

Odor Denial Syndrome: Can we have an "impossible biosolids" without odor?

I believe our biosolids profession suffers from an “Odor Denial Syndrome.”  Despite repeated evidence in my Google Alerts for “biosolids” that odor complaints precipitate most cases of adverse media coverage, you wouldn’t guess that this is a problem for us, based on the scant attention to odors during recent months of technical conferences.  April’s WEF biosolids conference in Fort Lauderdale offered 100 technical papers, yet only one dealt with odors, and those odors were in-plant emissions during drying. The IWA’s Leading Edge Conference on Water and Wastewater Technologies was held in Edinburgh in June 2019, and no technologies offered odor mitigation as an attribute. Our own organization, Mid Atlantic Biosolids Association, put out a call this past winter for presentations for its July 2019 conference, and no presentation proposal dealt with odors. (Still, please come, it will be great! Check out the brochure!)

The Merriam-Webster on-line definition of “syndrome” is “a set of concurrent things (such as emotions or actions) that usually form an identifiable pattern.” One non-medical example posted to the Internet is a “not-in-my-backyard syndrome.” So, I think I have a case here for calling out our “odor denial syndrome.” It is a concurrence of odor nuisance complaints by communities and an absence of effective mitigation measures by agencies and their contractors.

The power of syndromes was hammered home in what was, frankly, an unexpected article in the New York Times about the “Havana Syndrome”. This is a strange “brain” ailment suffered by employees of the U.S. Embassy in Cuba, first reported several years ago.  One suggested cause of the brain ailment was a microwave “acoustic attack” (Microwave weapon caused syndrome in diplomats in Cuba, US medical team believes), and another suggestion was poisonings (Were the Cuban ‘Sonic Attack’ Victims Actually Poisoned?).  But by the time of the recent NYTimes article Was It an Invisible Attack on U.S. Diplomats, or Something Stranger? a third hypothesis had gained primacy: “the diplomats’ symptoms are primarily psychogenic.” In other words, the diplomats’ ailments were what is popularly called “mass hysteria,” but more scientifically termed “mass psychogenic illness,” a premise well covered in the article “Mad Gassers, toxic buses and the Havana Syndrome: What society still gets wrong about the way stress can make us sick.”

I have been following the term “mass psychogenic illness” with Google Alerts for well over a decade, since I first made a case for biosolids odorants as a trigger for a special kind of syndrome. I put together a research paper in 2007 titled Biosolids Odorant Emissions as a Cause of Somatic Disease:  What is Our Profession’s Response? I argued that biosolids odorants are of a chemical nature likely to trigger in susceptible people a “psychogenic illness,” which manifests as symptoms that align with the “sludge syndrome” put forth in Ellen Z Harrison’s paper Investigation of alleged health incidents associated with land application of sewage sludges.  According to Harrison, the symptoms of the sludge syndrome “most common are respiratory and gastrointestinal symptoms, skin disorders and headaches. Other symptoms frequently reported by numerous people include nosebleeds, burning eyes, throat or nose, flu-like symptoms, and fatigue.” 

In my 2007 paper, I argued that “sludge syndrome” symptoms arising from odor nuisances are predictable.  The human nose is exquisitely sensitive to organic sulfide and nitrogen compounds, and adverse reactions may be genetically “hard-wired.” I argued that biosolids managers ought to plan for maximum odor containment and be prepared with an appropriate, proactive response to those people who display such reactions. I had push back from the some biosolids practitioners because I had amplified the suggestion of adverse health effects from odors.  Activists caught wind of the paper and were angered by my assertion that the “sludge syndrome” was all in their heads. I couldn’t win. What is more, the Havana Syndrome is, for me, evidence of how powerful psychological responses are as “health effects,” and of how important it is for our industry to better manage biosolids odorant emissions. If highly trained intelligence officials can be brought down by environmental triggers, so too can the neighbors to our land application sites.

What has been the history of our wastewater industry’s response to the very significant issues of odors? Well, until about the year 2000, we had had essentially no response. In that year we pulled together, both through MABA and joined by the Water Environment Research Foundation, a significant research focus. Now that we are in 2019, can we say we have solved our odor problems?  After all, many dozens of journal articles and conference presentations have been prepared, and WERF has its four-phase report, leading to the “Biosolids Odor Reduction Roadmap.” We learned that adding iron salts ahead of dewatering seemed to be one strategy, that using presses instead of centrifuges for dewatering seems to be an option, and that waiting a couple of days after dewatering for odorants to subside was also a useful idea.  But, for all our effort, no breakthrough on odor mitigation was discovered.  Yet, it seems that WERF declared the research done. My faithful attendance at technical conferences and recent Google Scholar searches did not reveal any recent U.S. based research project.

That is why I was so amazed at the odor research work coming out of Australia over the past several years. Specifically, this is research that has Ruth M. Fisher’s name on it, a research associate at the University of New South Wale’s Water Research Centre.  I have now in my library her eight journal articles on the topic of biosolids odorants published between 2017 and 2019 (mind you, Dr. Fisher is only one year out from completing her PhD). Let me list these publications:

·         Variations of odorous VOCs detected by different assessors via gas chromatography coupled with mass spectrometry and olfactory detection port (ODP) system 

·         Odorous volatile organic compound (VOC) emissions from ageing anaerobically stabilised biosolids

·         Distribution and sensorial relevance of volatile organic compounds emitted throughout wastewater biosolids processing

·         Influence of Biosolids Processing on the Production of Odorous Emissions at Wastewater Treatment Plants

·         Sewer catchment effects on wastewater and biosolids odour management

·         Framework for the use of odour wheels to manage odours throughout wastewater biosolids processing

·         Emissions of volatile sulfur compounds (VSCs) throughout wastewater biosolids processing

But it is Fisher’s 2019 review article on biosolids odors that, if I had my way, would be mandatory reading for all practitioners -- Review of the effects of wastewater biosolids stabilization processes on odor emissions.  She reviews over 200 papers, and, importantly, she makes sharp observations and points us to important work ahead.

Fisher makes clear that we do not yet have adequate odor analysis methods, protocols and tools. Let me provide quotations from her review:

·         “However, due to the large range of odorants which have been reported for all stabilization methods, the use any single analyte to represent odor is likely insufficient and will lead to the underestimation of odor impacts… the focus on only TVOSCs is potentially limiting.”

·         “From a methodological perspective, both sensorial and analytical methods are needed for odor characterization.”

·         “…the dominant burnt odor quality detected in emissions from dried biosolids has not currently been linked to a responsible compound, however, it is likely an important odorant.”

·         “...a Dried Sludge Odor Wheel, which reported odorants… shows a need for emission analysis using a combination of chemical and olfactory measurement methods.”

·         “…qualitative approaches to odor control… are limited due to our lack of understanding of emission composition. The identification of odorants and the sensorial implications can provide a clear link between process performance and nuisance impacts.”

Fisher believes we need to study far closer than we have to date the link between processes and odors.  Again, here are some pertinent quotations:

·         “…the upstream plant configuration or operational performance were rarely reported, which makes links between emissions and WWTP performance difficult to establish.”

·         “To date little success has been reported in predicting the odor quality of biosolids produced using other (than anaerobic digestion) stabilization processes based on process operation.”

·         “Despite the large amount of research into emissions from anaerobically stabilized biosolids, no single operational parameter was found to predict biosolids odor. However, general trends between odor emissions and dewatering, storage, digestion and chemical dosing have been identified.... none were able to reliably predict the resulting biosolids odor quality…”

Even when we have some clear relationships between process and odors, Fisher suggests that actions that would reduce odor risks are not chosen. Here are some quotations:

·         “The choice of stabilization methods for biosolids processing should be influenced as much by the operational requirements of the process as the desired properties of the biosolids product.”

·         “It is vital that the odor implications also be considered when evaluating process performance.”

·         “…the emerging relationships between process instability and downstream biosolids odor emissions, reinforce the importance of stable operation and good process monitoring and control.”

·         “Stabilization processes which rely on the disinfection of biosolids, such as alkaline or thermal treatment, are heavily influenced by previous sludge handling as the organic content has not been significantly altered during stabilization.”

·         “When wetted and applied to soil, the dried un-stabilized biosolids were judged as the most offensive, presumably due to the production of VFAs and sulfur compounds due to microbial activity on the remaining organic matter.”

·         “the storage or land application of the stabilized biosolids with high organic matter content typically lead to more unpleasant of odors, compared to those which had originally been digested and had lower organic matter contents.”

The Odor Denial Syndrome is far worse than I have acknowledged to myself in the past. It leaves us vulnerable to justifiable public criticism, and it undermines our claim to environmental stewardship.  Odorant emissions are the biggest source of risk to the wastewater profession arising from community, political and regulatory upset. Yet, our industry persistently fails to hold as a central focus in its design of facilities and operations the objective of minimizing odorant qualities of biosolids. New treatment technologies are almost never evaluated for the odor quality of the biosolids they produce. Standard operating procedures at our plants do not generally encompass “best practices” for minimizing odorant formation in the biosolids product.  Public bidding documents for land application services seldom accommodate contractor activities that are responsive to minimizing odor releases, as might be accomplished through responsive storage and application practices.

I propose we fashion for ourselves an alternative narrative about biosolids odors and to genuinely commit to its outcome: we must develop technologies and practices that prevent public odor nuisances.  To do so, we need to be committed to change.  I recently read that “2019 is the year of faux meat,” as start-up companies are successfully introducing the plant-based Impossible Burger and Beyond Burger for those who wish to change their meat-eating habits. With apologies to their marketing gurus, I propose that we have an alternative so incredibly transformational that we can brand our new narrative the Impossible Biosolids. 

Blockchain Biosolids: How Digital Technology Can Revolutionize Biosolids Management

 

“Trust and Transparency,” that is the promise. I was snagged by the Facebook Ad offer for a lecture by George Gilder on how the coming revolution in digital technology would protect privacy, honor creativity, and guarantee security, hence accomplishing “trust and transparency.” If I had two words to describe what biosolids managers are missing most in their work with customers, community, and regulators it is those very things - trust and transparency.

I ordered for $13 Gilder’s book, Life After Google. This was not much of a risk in my mind. After all, I had intended to learn more about 5G, bitcoin, blockchain, and other terms that have been entering the lexicon of savvy professionals. And if I could learn how to achieve “trust and transparency,” $13 was worth the risk.

Wastewater professionals see themselves as the “hidden infrastructure.” Compared to roads and bridges, that is true, but compared to the digital infrastructure, we do not compare. Even the very digitally “woke” among us are likely to see the digital infrastructure as opaque. Yet the scale is beyond most imaginings, with a typically large data center a million square feet, costing a billion dollars to build and requiring 100 MW of power. These comprise not a culmination of technology investment, but a way station on a moving sidewalk that has not slowed over the decades. That the “cloud” now shapes much of the way even wastewater managers upload and download facility data, against a recordkeeping approach that is keyboard-typed spreadsheets on desktops, the next step may involve “sky” technology and a system of data reading that bypasses human eyes, comprising “life after Google.” George Gilder’s book is an introduction into the post data-center world, that of networked supercomputers, laptops, and cellphones in vast, distributed relationships. Pulling these together is "Distributed Ledger Technology (DLT)," also known as Blockchain Technology. The “block” in blockchain are "transaction blocks," information units that are assigned a "cryptographic code" to which participants in the transaction have secure access. 

The global digital revolution has not greatly transformed municipal wastewater treatment. But what might biosolids management look like if a “Life after Google” type transformation took hold?  Bitcoin is the most familiar transaction block that is tracked by DLT, but what if a load of biosolids was just such a block?

Digital records of today’s biosolids processing and use are not deliberately “chained” together. But what if we changed that?  What if, with DLT, or Blockchain Technology, the data we could collect at every step of the biosolids value-chain, from influent, through the WRRF, out to the user and into the soil or energy facility, were the input to Blockchain Biosolids records? A large, and increasing, number of monitoring, reporting and verification data (MRV) could be collected and “chained:” sensing influent quality, measuring nutrient and pollutant concentrations, reporting processing statistics, tracking transportation movements, documenting land applications, connecting to crop yields and soil test results, matching to unmanned drone photos, estimating carbon sequestration, nitrogen and phosphorus loadings to farm soils, and connecting to odor complaints. These data could be used for complying with regulations, monetizing nutrient trading, and meeting agronomic targets. Farther in the future, as wastewater systems work to improve effluent quality, blockchain networks can be used to track, for instance, the surveillance of pollutants in consumer products and pathogen releases to sewage.  The digital revolution and data management through blockchain could empower treatment plant owners to accomplish improved biosolids quality. 

The first step on the Biosolids Blockchain is wastewater quality. Wastewater surveillance is an upcoming digital technology that ought to benefit the quality of biosolids. The 2019 WEFTEC paper “Effective Utility Management in a Digital World“ speaks to a Memphis project with ”the opportunity to intervene on pollutants and to maximize the destruction of pollutants and biological constituents.” The novel coronavirus has ensured a place in popular culture for a growing interest in sensing influent pathogens (Computational analysis of SARS-CoV-2/COVID-19 surveillance by wastewater-based epidemiology locally and globally: Feasibility, economy, opportunities and challenges).  But researchers have targeted poliovirus (Evaluation of Secondary Concentration Methods for Poliovirus Detection in Wastewater) and other compounds public health interest (24-hour multi-omics analysis of residential sewage reflects human activity and informs public health), such as  illicit drugs, smoking prevalence and dietary habits (e.g., Alcohol and nicotine consumption trends in three U.S. communities determined by wastewater-based epidemiology and in the Assessing the Potential To Monitor Plant-Based Diet Trends in Communities Using a Wastewater-Based Epidemiology (WBE) Approach).

The second step of Biosolids Blockchain is treatment plant performance. Digital technology promises a future of optimized effluent treatment. It could be something apparently easy, such as  Evaluating the performance of a simple phenomenological model for online forecasting of ammonium concentrations at WWTP inlets; this is a report of an effort to optimize energy and chemical inputs for aeration and nitrogen removal.  WRRFs of the future could be highly automated, monitored in real time and controlled remotely, as offered in this article Augmented reality, an ally in water treatment processes.  The “holy grail” is a fully integrated system for an entire plant, as envisioned in Artificial Intelligence in Wastewater Treatment Facilities: Implementing Practical New Technologies for the End User. Accenture Water Analytics, IBM Intelligent Water Platform and Veolia Water Technologies Aquavista are three initiatives in the smart wastewater space.

Two stops in the treatment plant seem to cry out for digital enhancement of the biosolids “value chain.” The first is automated control of stabilization, e.g., anaerobic digestion. Automatic process control in anaerobic digestion technology: A critical review evaluated available automatic control technologies that can be implemented in AD processes at different scales, and other papers (Lessons learnt from 15 years of ICA [instrumentation, control and automation] in anaerobic digesters  and Nonlinear process control of anaerobic sludge digester) offered cautious notes about the practicability of digitally-guided operations, even as such tools as “proportional-integral-derivative (PID) controls,” “fuzzy logic controls (FLC),” neural networks, and artificial intelligence are applied. The second stop for digitally enhanced biosolids “value chain” is dewatering. Optimal solids content in biosolids is an interplay of feed quality, chemical inputs, and equipment settings to which sensors and feedforward and feedback control logic can be applied. Three leading offerings in this area are Valmet, with its dry solids measurement equipment, Hach with its RTC-SD (Real Time Controls for Sludge Dewatering), and RealTech on sensors of excess polymer dosing.  Each point of data collection is a “block” in the chain of information on biosolids quality.

After a Biosolids Blockchain record has taken in data on influent quality, stabilization performance and dewatering, the next stop on the value chain for data collection is transportation of biosolids loads to the user or customer. Over the past decade, the vehicle tracking system is nearly universally adopted, providing origin and destination data of biosolids haulage, matching weigh tickets issues at the production plant with records at the field.

Precision agriculture sets a high bar for digitalization of farming operations. Documentation of field application of biosolids is the next step in blockchain.  John Deere introduced two decades ago its GPS guidance systems to record farm tractor operations, and the firm even has the HarvestLab 3000 “manure constituents sensing laboratories” outfitted on manure application equipment to calculate in real time nutrient applications. An up-and-coming technology is UAVs, or “unmanned aerial vehicles” that can check on nutrient needs, soil conditions and equipment operations (see, for instance, The Role of Drone Technology in Sustainable Agriculture.)  At harvest time, digital equipment can estimate crop yield, as with the John Deere ActiveYield.  Were digital information collected at the farm site of biosolids spreading and crop performance, this would be another block added to the chain, with the connection between biosolids and crop growth objectively documented.

Biosolids recycling benefits soil, and blockchain can provide the records demonstrating this benefit. The United States is an international leader in creating digital agricultural laboratories.  Major issues in agricultural use of biosolids, such as soil phosphorus accumulation, pollutant concentrations and soil organic matter, are all subject to analytical documentation through soil tests. Analytical reports of soil samples linked to biosolids applications in time and location can be exported automatically from the laboratory to the biosolids blockchain records. With this data record, the blockchain is complete, from influent through to soil.

Global climate change is an urgent issue about which biosolids managers can play a role, particularly if blockchain is part of rigorous recordkeeping system from which biosolids managers work. This opportunity is offered, for example, by green technology investment advisors in The Time is Now: The Blockchain Platform for Carbon Offsetting, Green Financing and Sustainable Investments.  Privately funded ventures propose deploying “value-chain incentives” for carbon sequestration, as with the “deep demonstrations of turning landscapes from carbon sources to sinks” described in About Landscapes as Carbon Sinks.  The rigor of the blockchain data system can make this possible for the wastewater profession, as it facilitates conformance by our industry to rigorous procedures for carbon accounting. For instance, the Soil Enrichment Protocol: Reducing emissions and enhancing soil carbon sequestration on agricultural lands is nearing adoption by the Climate Action Reserve.

The wastewater profession’s capacity to collect data on processes and practices has typically outstripped its capacity to draw out knowledge and meaning from that data. The kind of digital revolution and “internet of things” that has propelled Google and others to the world’s center stage has widened the gap between our customary practices and the reasonable expectations of our customers for how environmental technologies ought to work in a digital world. The “trust and transparency” that seems to be missing in our relationship with customers and neighbors is not an intentional strategy but rather a failure to invest talent and resources in bringing digital technology solutions to biosolids management. We need a digital revolution, and that revolution can begin by Embracing Blockchain Biosolids.

Remarkable Memes

Just blame Maile.  Because of Maile Lono-Batura, executive director of Northwest Biosolids, I have spent (wasted?) several hours trying to figure out “memes.”  According to the website 50 Internet Memes that Have Won Our Hearts: Viral humor, bizarre curiosities, and infectious storytelling, “Memes are cultural symbols and social ideas that spread virally. The meme content itself is usually something of minor every day. The noteworthy aspect of a meme is its infectious nature: It invites people to spread it through social media, email, and photo-sharing.”

Did you get that? Memes are those pesky distractions you get when you are moving through the internet, something catches your attention, and, suddenly, you are off course.  Clearly, I don’t get distracted enough or I would not have missed The Extreme Diet Coke & Mentos Experiments and Build Your Own Demotivational Calendar. Had I come across this “meme,” featuring one of my heroes, I would have been guilty of assisting its “virality:” Mr. Rogers Remixed: Garden of Your Mind. But believe it or not, I had no idea that number one on the list of “50 favorite memes” is the meme “Be Like Bill,” for which I am flattered, sort of.  Be Like Bill is “a passive-aggressive meme, featuring a stick figure, that comments on people's life choices.”  For example, “This is Bill. Bill is on the Internet. Bill sees something that offends him. Bill moves on. Bill is smart. Be Like Bill.” I guess that is what happens when I see a post from a familiar anti-biosolids activists.

Maile and I were discussing viral internet postings last week.  I mentioned I had heard an interview on TED Radio Hour with internet marketer/blogger Seth Godin.  Godin’s website urges us to “Go make something happen,”  which I try to do every day, but with small effect. In his TED Radio Hour interview, What makes an idea go viral , Godin says that for ideas to go viral they need be “remarkable.” That is, the idea or product is so engaging that people are motivated to “remark” to family, friends and others about the idea. Hence, spontaneous person-to-person remarks make the idea go viral.

In our biosolids world, very few of us have the goal for our biosolids to be “remarkable,” because the remarks are usually of the wrong kinds, and they go viral for the wrong reasons.  That is what we need to change. We need to tell our “remarkable” stories, and we need positive viral results.

Maile and I mused over what it would take for the biosolids profession to tell “remarkable” stories. This is when Maile told me about crickets. A Portland based company, Cricket Flours, poses on its website the question: “Are You Ready for Crickets? Natural, sustainable, protein,” and goes on to explain “Cricket Flours LLC was founded in 2014 to provide an environmentally friendly and sustainable source of protein and nutrition for the world’s expanding population.”

But it is a Brooklyn NY company using cricket flour that introduced a unique communication approach, with a useful lesson for biosolids. Exo Protein is a start-up enterprise founded in 2013 by two Brown University graduates who, following a lecture on sustainable business, came up with the idea of manufacturing high protein nutrition bars using cricket flour.   The company is pumping along happily with their Exo Cricket Protein Bar when it unexpectedly starts getting nasty posts on its comment page. The good folks at Exo Protein were stunned.  As the company explains on its website: “We’ve also received our share of hate mail, from internet trolls to the flat-out squeamish. Some of these comments are simply too great to keep to ourselves. Check out the best (worst?) below. And to all of them we say: Haters Gonna Hate.”

“Haters Gonna Hate” is a meme. According to LifeWire: “'Haters gonna hate' is an expression of personal pride and individuality. It means 'I'm just going to ignore the cruel and hateful comments of other people'. The 'haters gonna hate' expression is commonly used when a person (or animal) performs some kind of public strutting move that demonstrates individuality, and that person wants to shout, 'I don't care what other people think!'
If there is a meme that biosolids managers might be able to embrace for themselves, when confronted by media and local opposition, it is “haters gonna hate.”

Exo Protein’s hate comments, which they posted bravely on its website, included these two: “You “environmentally conscious” morons can eat bugs and #$%$ for all I care” and “How much longer before these idiots try to get us to eat our own #$%$?“.

We have here a literary conflation of icky bugs and poop. I wasn’t expecting this, but it struck a chord. 
I was reminded of a paper I presented at the 1998 WEF RBC Opening General Session, “The Horror, Humor and Heroes of Biosolids.” I opened up with a news article that featured a very special biosolids utilization outlet: hamburgers.  Fortunately, Google has archived the article from World Weekly News: The World’s Only Reliable News. You can read it for yourself. “Potty Patties: Hamburgers made from raw sewage are a big hit in Japan.” 
Back in 1998 I had tracked down and reported on the very, very small kernel of truth behind this story. Here is what I wrote: “The Japanese actually did undertake this research!  Mr. Tomozane, in an email message to me, writes ‘We have now completed the project of creating artificial meat from the sludge left over after waste water treatment and have a real product.  We have both dried out meat for immediate usage and we also preserve the meat by storing it in vacuum packs… We have further plans to investigate and research into new areas of using extracted protein for valid purposes.’ “

To my delight, the “urban legend” of sewage to hamburger did not die in 1998.  In 2011, we read:  Japanese scientist creates 'poop burger'? Surely not: “A Japanese scientist reportedly finds a way to do something ecologically useful: create artificial meat from sewage containing feces. But doesn't the story smell just a little funny?”  This comes complete with a YouTube video Solution to the Global Food Crisis - Let them eat TURD BURGERS.

I think this article is further evidence that our culture is turning the corner on its relationship to poop management.

Have you seen the short film Gut Hack?  Biohacker Josiah Zayner has been plagued by gastrointestinal pain: “Rather than swigging some Pepto-Bismol, Zayner has other ideas, searching for someone ‘hopefully really athletic and attractive’ to swap out bacteria with to see if it’ll improve his health.”   He swallowed home-made capsules of donated feces. His gut microbiome was transformed, and he was restored to good gastrointestinal health.

Popular culture is embracing the gut microbiome and its effect on our health. A Johns Hopkins website describes Fecal transplantation (or bacteriotherapy):“This is the transfer of stool from a healthy donor into the gastrointestinal tract for the purpose of treating recurrent C. difficile colitis.”   We learn from the Open Biome website about  Fecal Microbiota Transplantation, and we learn How to Own Your Gut Bacteria and Fix Leaky Gut Syndrome. Even more extreme, in line with “Gut Hack,” we can learn The Power of Poop, with “DIY Fecal Transplants at Home.” At home?!
I sense from the “meme” interest in this topic that we may be witnessing in society decreasing “fecaphobia,” broadening interest in the cycle of wastewater, and newly positive associations with “germs.” AsapSCIENCE, with funding by SquareSpace  (coincidentally MABA’s new website host) produced this supportive description of The Poop Cycle.  I can tell you from personal experience how exciting it was to receive my gut microbe profile from American Gut; I have 13 times more organisms of the genus Prevotella than is typical in the U.S.  NYC Radiolab, which has done the biosolids industry great service by producing two programs: Poop Train (9/24/2013)  and The Sludge at the Bottom of the Sea (11/13/2013), this past week featured a story, Funky Hand Jive, describing the transmission of microbes by handshakes.

Radiolab’s special guest for this “handshake” show was astrophysicist Neil deGrasse Tyson.  Dr. Tyson is one of the nation’s most recognized science popularizer, filling holes left by Carl Sagan’s death and David Attenborough’s age. The 1 May 2017 issue of Chemical and Engineering News acknowledged Dr. Tyson’s importance, in a commentary by the 2017 American Chemical Society president Allison A. Campbell, Communicating science effectively to the public. Her concern, reflecting on the March for Science demonstrations this past Earth Day, was that “Social media, predominant as they are today, amplify the perceived risks of communicating with the nonscientific public.” She urged us to move past the perceived risk and instead to commit to communicating the science behind our work. She suggested we adopt four principles: understand the audience, tell good stories, speak plainly, and play the long game.

We certainly have a way to go, as we prefer to talk to ourselves, tell complicated stories, use jargon, and worry about tomorrow’s news articles.

And, we resist being remarkable.  I don’t have a good answer yet on the kind of “remarkable” meme that would spark a positive, viral interest in biosolids recycling. It might have elements of ‘Haters Gonna Hate’ and ‘Gut Hack’, but I would prefer it come from the kind of work that is done in support of compost by Kiss the Ground, which celebrates the role of microbes in the soil-food web and in building soil health.

I spoke to Charlotte’s Jean Creech last week. She said she was taking the cue from California Association of Sanitation Agencies and Northwest Biosolids to turn the conversation away from nutrients, regulations and risk and toward soil health. This is where we can tell our remarkable stories. This is  the foundational “long game” issue, and we can focus on good results, not on technologies. We need to keep our audience in mind, or in this case, the REMARKABLE MEME IN MIND.

Hot Stuff in Landfills?

My spouse shook my world the other day!  A tedious conference call at work had her scrolling her Facebook feed, and, as she is a nerd like me, her feed has some great science stories. I was busy with my own biosolids science inquiry, so I was inclined at first to ignore her FB messenger notes.

But how can you ignore Records Found in Dusty Basement Undermine Decades of Dietary Advice? We all know a plant-based diet is the pathway to good health. But National Institutes of Health employee Christopher Ramsden had uncovered a trove of 9,000 patient files of a seminal nutrition study completed 40 year ago, the data from which, when reanalyzed, turned upside down the conventional wisdom that a diet high in saturated fats increased risk of deaths due to heart disease. The data showed the opposite!

What?! I have been eating bean burgers when my health would have been better served by beef burgers?

And, a short while later, another FB Messenger note from my wife excitedly urged me to read about plastic-eating waxworms. We all know that the health of soils and oceans, on which human existence depends, is ultimately doomed by accumulation of plastic, particularly of the micro kind.  But here the LA Times was announcing, in Stubborn plastic may have finally met its match: the hungry wax worm, “researchers set wax worms loose on a polyethylene film, watching holes appear after just 40 minutes… So far, the scientists are not sure whether this ability is due to the wax moth larva, or to the microbes within its gut.”  I went to Google Scholar to find, despite being a faithful reader of Engineering Science & Technology, I had missed an article back in November 2014 (Evidence of polyethylene biodegradation by bacterial strains from the guts of plastic-eating waxworms) announcing “the results demonstrated the presence of PE-degrading bacteria in the guts of waxworms and provided promising evidence for the biodegradation of PE in the environment.”

I should have known, gut bacteria are the heroes; they even eat plastic. Maybe humanity is not doomed, not yet at least, by plastic.

All of this “news” had distracted me from my own biosolids investigation of the bizarre. I had been uncovering a wholly unexpected adverse environmental effect of biosolids.  Let me hasten to say, there is NO FIRM EVIDENCE, not yet at least, that biosolids is responsible for this: Elevated Temperature Landfills.  

For the better part of 30 years I have held the firm conviction that biosolids co-disposal with municipal solid waste (MSW) is a win-win, filling in space-wasting voids in the emplaced trash, hastening biogas production and accelerating settling. Biosolids co-disposal is so beneficial for MSW landfills that it warrants a discounted tipping fee, I would argue (unsuccessfully so with landfill companies).

What I know is true, like plastic is forever and animal fat ruins hearts, may not be true!

Eminent emeritus Virginia Tech professor John Novak had first planted the doubt, which I mostly ignored. In his keynote presentation to the 2015 WEF biosolids conference, Dr. Novak darkly warned, almost off-handedly, against over reliance on co-disposal at landfills, as disposal challenges go beyond odors. In a casual follow-up conversation with Dr. Novak I first heard the phrase “elevated temperatures.”

There the matter lay, until the recent 2017 WEF Conference in Seattle. From another industry insider, I learned a research project had been launched to study Elevated Temperature Landfills (ETLF). This was no small investigation. Major companies had gotten together to fund it. A highly-credentialed team had been assembled. Some extraordinary situations had been reported by the press. 

I did some Internet sleuthing and followed with interviewing. The Environmental Research and Education Foundation, formed as a research arm of the solid waste industry in 1998, requested proposal to study ETLF in 2015, resulting in CCL receives Environmental Research & Education Foundation (EREF) funds research grant on elevated landfill temperatures.  This team is led by Dr. Marco J. Castaldi, an engineering professor at the City University of New York (CUNY) and includes Dr. Morton A. Barlaz, professor at North Carolina State University.  A PowerPoint presentation posted by Dr. Barlaz, Heat Generation and Accumulation at Municipal Solid Waste Landfills Experiencing Elevated Temperatures, provides eye-popping descriptions of ETLF at work and the importance of the new study.

A Google search points to at least one shocking situation. The online waste industry publication Waste360 has tackled this topic, first with a March 2016 overview ( Elevated Landfill Temperatures a Concern for Operators ) and then with a three-part series of articles on elevated temperature landfills ( Diagnosing and Understanding Elevated Temperature Landfills ).  In November 2016, Waste360 provided  The Bridgeton Landfill "Fire" Explained (Updated), in which the story of the St. Louis, Missouri, landfill owned by Republic Services, is described.  This is already national news, albeit National Public Radio:  Landfill Fire Threatens Nuclear Waste Site Outside St. Louis.  According to the NPR article, “Specifically, Acting EPA Regional Administrator Mark Hague says there is "no imminent threat" of the underground fire in what's known as the Bridgeton Landfill reaching the radioactive waste at the adjacent West Lake Landfill.”

Do you feel reassured?

Another research team in Louisiana is “hot” on the trail of symptoms and causes of elevated temperature landfills. Navid H. Jafari is the lead author of Spatial and temporal characteristics of elevated temperatures in municipal solid waste landfills. The authors state: “In particular, MSW landfills undergo changes in behavior that typically follow a progression of indicators, e.g., elevated temperatures, changes in gas composition, elevated gas pressures, increased leachate migration, slope movement, and unusual and rapid surface settlement.”

So far, no mention of biosolids in on-line PowerPoints or by the media.

Nevertheless, the hallway conversation in Seattle turned to a recent tragedy at Greentree Landfill in Kersey, PA, this past February.  One article among many is Worker’s Body Found After Being Buried In Trash At Pa. Landfill.  The speculation heard in Seattle is that the surface instability at Greentree arose from a “hot spot” associated with a high proportion of biosolids disposal accepted at this landfill. 

When Waste Management, Inc., (WM) took steps in February 2015 to change its policies on biosolids acceptance, the principal assumption was its impetus was odor complaints.  That this step should apply to WM’s Pennsylvania facilities seemed to be reasonable (Pennsylvania Orders Waste Management to Close Tullytown Landfill by 2017). After all, NYC DEP, a major customer at the time, does not certify its biosolids as compliant with Class B pathogen standards or with Vector Attraction Reduction standards, and Pennsylvania regulations seem to require this level of stabilization for landfill acceptance.

But WM’s policy on biosolids co-disposal may include other considerations – for instance a risk of elevated temperature.  A recently retired WM engineer explained in a recent interview that no WM landfills receiving a proportion of biosolids lower than 10 percent of daily trash acceptance had displayed problems with elevated temperatures. While this is not a basis for a cause/effect relationship, if you are a landfill operator a reasonable course of action is to impose a 10% maximum acceptance rate for biosolids. That is what WM did in 2015.  Other landfill owners, including Greentree’s, did not.

But how could biosolids be involved with elevated temperatures?  In Waste360’s  Diagnosing and Understanding Elevated Temperature Landfills (Part 3), the authors suggest the reaction is  “Pyrolysis… the thermochemical decomposition of organic matter at elevated temperature in the absence of oxygen.”  As a follower of the WE&RF LIFT program, I recalled the proposal from a start-up enterprise, HydroTORR’s ZIP-Carb (Zero Input Process Carbonization), deploying hydrothermal carbonization (HTC), a wet-state thermal decomposition under elevated temperature and pressure in an oxygen starved environment, very pyrolysis-like.  That modern landfills are hundreds of feet thick, totally insulated, oxygen-free and wet with recirculating leachate, internal conditions are seemingly consonant with HTC.

One researcher involved with HydroTORR is Dr. M Toufiq Reza, formerly of University of Nevada, now at Ohio University, Athens. He has a specialization in “applied bioenergy.” When I put my hypothesis to him, Dr. Reza gave it a few hours consideration and in an email back to me suggested that high strength leachate combined with biosolids sealed in waste cells under pressure “might go for an exothermic decarboxilation reaction resulting in CO₂ and heat.” These are the two key indicators of elevated temperature landfills.  

The science is still not there to link biosolids and elevated temperatures, at least not yet. But, if science can surprise me with contrary conclusions on plastic and lard, it can surprise me with contrary conclusions on biosolids in landfills.

I participated in the March for Science in Philadelphia on Earth Day. It was a perfect venue for me to recommit to keeping science front and center with biosolids. Dr. Reza wrote: “To test the hypothesis, I may need to test the leachate sludge and aged-sludge.”  He stands ready to do some research, and I invite you to join me in elevating the SCIENCE OF HOT BIOSOLIDS.