Gut Check!

I have a tremendous idea for a new biosolids research project, but first….

It was no big surprise that one of my wife’s Christmas gifts to me was Gut: The Inside Story of our Body's Most Underrated Organ.  I have displayed at home, as well as in my biosolids commentaries, an abnormally high interest in the human gut microbiome.  To my delight, this book, translated from German and written by Giulia Enders, a young female, award-winning, Ted-talk-giving, science writer, is a breezy and comprehensive work. It is, as Amazon says, a “beguiling manifesto.”

Clearly, one of its main messages is that the health of the human gut microbiome effects the health and well-being of its host, that is you and me.  I checked with Amazon, and Ender’s “gut” book shares the virtual bookshelves with a whole host of similar titles, also drawing on the connection between happy microbes and happy people: The Microbiome Cookbook: 150 Delicious Recipes to Nourish your Microbiome and Restore your Gut Health, The Mind-Gut Connection: How the Hidden Conversation Within Our Bodies Impacts Our Mood, Our Choices, and Our Overall Health,  The Good Gut: Taking Control of Your Weight, Your Mood, and Your Long-term Health

This flurry of book is all very new, each book printed in 2016.

Then the news services on January 3rd reported that a new organ had been uncovered in the human body, one connected to the intestines, and called the “mesentery.” Another young female science writer with Live Science, Sarah G. Miller, wrote the article Gut Decision: Scientists Identify New Organ in Humans:  “scientists can now focus on learning more about how the organ functions, Coffey said. In addition, they can also learn about diseases associated with the mesentery, he added.” 

I can confidently assert that we will be hearing a lot about gut flora over the next decade, and we should take note of this for our work with biosolids, particularly for the positive connection between microbial communities and human health. A major research question was which gut microbes caused major gastrointestinal illnesses, such as Crohn’s Disease and ulcerative colitis, in hope of an easy path for medical control. But the nature of gut ecosystems was too complex for a simple answer. Instead researchers turned to the question how the gut ecosystem actively keeps us all healthy, particularly when so many species of gut microbes are known human pathogens.  

Over the past several years, journal articles have addressed these questions:

·        Does choice of foods affect the microbiome? Well, yes, at least in part (Long‐term monitoring of the human intestinal microbiota composition).

·        Does use of antibiotics alter the gut flora? Well, yes, at least in part (Diversity, stability and resilience of the human gut microbiota).

·        Does consuming daily doses of probiotics alter the gut flora? Well, yes, at least in part (Intestinal microbiota in human health and disease: the impact of probiotics). 

·        Is obesity influenced by gut flora? Yes, at least in part  (Linking the gut microbiota to human health).  

·        Can gut flora really influence an individual’s emotional well-being? Well, yes, at least in part (Better living through microbial action: the benefits of the mammalian gastrointestinal microbiota on the host).

Wow! Who would have guessed that our health and well-being is really the result of our wonderful gut flora?

I realized in reading these reports that I had only a foggy idea of what comprised the human gut flora.  We are all familiar with E coli as an important class of bacteria, but its distinction for us is not in its role in the human microbiome but its choice as an indicator of environmental contamination.  And, as it turns out, it is not a particularly good indicator at that.  Escherichia coli is just one species in a large class of protobacteriods, a group that together makes up perhaps a quarter of the 3 trillion microbes in the adult human gut. E coli’s role is relatively small in the gut, but its presence in activated sludge treatment works turns out to be very significant, which is one reason (along with its easy culturability in the laboratory) we know so much about it, why we track it, and why we regulate it.

But we are learning of far more important microbes.  One particularly interesting microbial group in the gut is called Lachnospiraceae.  Besides its very dominant role in the gut flora in a class of organisms called the Firmicutes, this group is interesting because it connects to my next topic, the sewerage system. One young, female professor in Wisconsin, Sandra L. McLellan, has emerged as a leader in researching the unique microbial ecosystem of sewers. She has identified the class of bacteria Lachnospiraceae as a robust indicator of human fecal waste, occurring in the human gut and in the sewer, and being distinct from microbes from other animal and environmental sources.  Check out her paper, Sewage reflects the distribution of human faecal Lachnospiraceae, showing that public sewers fed with human-sourced food are the habitat for unique microbial communities, and this one microbe class that can be readily tracked, the Lachnopriracea. You heard it here first.

Just as we are on the early part of the learning curve of the microbial communities of sewers, the same is true with biosolids itself.  This brings me to Kyle Bibby’s work while a PhD student at Yale University, where he characterized the biota of different biosolids products.  In his paper, Pyrosequencing of the 16S rRNA gene to reveal bacterial pathogen diversity in biosolids, his intention is to clarify the potential array of pathogenic organisms, viruses as well as bacteria, that may be present in biosolids. But his work necessarily included a broader survey of microbial.  He discovered that different processes, such as aerobic versus mesophilic anaerobic digestion vs composting, resulted in biosolids with microbial ecosystems common within processes but different between processes.  Wastewater plants grow out of the influent food and microbes different biosolids-based microbial communities, each characteristic of treatment facility processes.

In his presentation to the MABA Annual Symposium, The role of microbes on soil health and questions for biosolids research, Dr. Jeffrey Buyer had covered Bibby’s work, but then extended the conversation to the effects of biosolids on soil microbial communities. He summarized soils research that showed many soil communities are stable, just as in the human gut, and that additions of various organic feedstocks, biosolids along with manures, help to push around, but not to fundamentally change, those soil microbial communities.  Where we humans might eat a carton of Greek yogurt for our daily dose of probiotics, our annual application of biosolids may do the same for a healthy soil.  Biosolids microbial communities make soils happy.

Dr. Buyer’s presentation this past November reminded me that Dr. Xunzhong Zhang at Virginia Tech, made a presentation to the 2013 MABA Annual Symposium, “Biostimulants Released from Biosolids have impact on Crop Stress Tolerance and Yield.”  Dr. Zhang showed that biosolids release auxins and stimulate soil microbes to do the same, which together significantly increase crop growth. He shows that biosolids makes for happy soil microbes, in turn making plants happy.

So where have I gone with this? Our historical engagement with biosolids microbes has largely been in what goes wrong in controlling pathogen indicators in our treatment processes or where their presence in the environment is a marker for pollution. Instead, what we are learning, starting with the human microbiome, is how critical complex microbial communities are for health -- the health of our bodies, the health of transformative processes in sewers, the health of our activated sludge treatment systems, and in the health-giving properties of biosolids for plant growth. 

The analytical tools are at hand and affordable, and only our imagination limits the questions we can ask. This is my research question.  What attributes of biosolids microbial communities contribute most to a positive growth response in plants, and how can we design our treatment plant equipment to optimize those attributes?  Instead of “high quality biosolids” research focusing mainly on attributes of odor, aesthetics, and handleability that influence human sensibilities, let’s look at biosolids from the viewpoint of the healthy plant.  That would be a worthy research project. At least, that is what my gut tells me!

Stop the POP!

Research on POPs is really popping.  We are learning at an accelerating rate of the fate of “persistent organic pollutants,” or the POPs, flushed down home drains and treated in systems where biosolids are destined for farm soils.

Our POP research rate may not be fast enough for some, as I learned very recently. David Lewis, long-retired from EPA but not from anti-biosolids activism, has posted to the United Sludge Free Alliance his recommendation for a new EPA Clean Soil Standard. I was reminded of just how “chemophobic” or “chemonoic” some people can be.  Dr. Lewis’s report would have you believe the threat from POPs is significant and growing. It is neither, and accumulating research shows this to be true.

We are not only learning about POPs, we are reducing POPs.  Back in the summer, the FDA issued a rule banning triclosan, triclocarban and other antibacterial POPs found in soaps and toothpaste.  We learned from Dr. Arjun Venkatesan, Arizona State University, in his presentation to the MABA Annual Symposium, that this action will remove more than half of the POPs that find their way into biosolids. 

Dr. Venkatesan has a unique vantage point to see POPs in biosolids. He is principal author of 7 science reports stemming from exhaustive analyses of the U.S. National Sewage Sludge Repository. The repository is a collection of representative biosolids samples, originating with three national surveys conducted by the US EPA two decades back, and now under the direction of Dr. Rolf Halden, Center for Environmental Security. Dr. Halden is “a noted expert in determining where in the environment mass-produced chemicals wind up…” and that expertise encompasses biosolids.

Dr. Halden has recently made the point that widespread use of industrial chemicals ensures that new questions about these chemicals will arise continually and science will be ongoingly playing catch-up to understand their potential effects on human and environmental health. Dr. Rolf Halden described the generation-long process well in Epistemology of contaminants of emerging concern and literature meta-analysis.

As environmental stewards, we biosolids practitioners necessarily need to support sound scholarship into POPs.  The chemical and biological matrix in which POPs occur is highly complex and reactive, and the science will be deeply complicated.

The European Union seems to lead the way in addressing the fate of POPs.  It has for two decades guided the testing for degradability of chemicals (OECD Degradability Testing) with a guidance document listing 7 types of tests. One test deploys a “301C sludge,” an “activated sludge precultured with synthetic sewage containing glucose and peptone.” Another is the 314 test which simulates transformations of chemicals in a sewer system.

In the US, the Water Environment & Research Foundation has led the way in POP research.  Currently at work is Dr. Drew McAvoy, the principal investigator of the fate of flame retardants and two antibiotics in biosolids. His project on  “Priority Trace Organics” appears right above “High Quality Biosolids from Wastewater” on WE&RF’s list of Recent Contract Awards. 

Those of us with an eye on biosolids may not be fully aware that POP degradability is being studied in different portions of the wastewater system.  These include the sewer system, the activated sludge process, nutrient removal processes and several kinds of digestion. Researchers are learning that unique microbial communities at work in each step can be important to the attenuation of POPs.

If we still believe the sewerage system is a mere collector, how wrong we are!  One paper shows that “biodegradation in the sewer has a substantial impact on levels of surfactants and surfactant metabolites that ultimately reach wastewater treatment plants” (Biodegradation of nonionic and anionic surfactants in domestic wastewater under simulated sewer conditions). Another researcher, hoping to track illegal drug use, complained “in sewage epidemiology, it is essential to have relevant information of the sewer system” (Effects of sewer conditions on the degradation of selected illicit drug residues in wastewater) .

The fate of POPs within the treatment plant has proved enormously difficult to characterize. Classes of compounds degrade through different mechanisms, with water solubility being a key discriminator for biosolids-borne or effluent-borne POP discharges.  Plant configurations vary, with the cycling of aeration, anoxic and anaerobic processes apparently having great influence on POP degradation. One article pointed out that “biotransformation parameters are impacted by in-situ carbon loading and redox conditions (Factors impacting biotransformation kinetics of trace organic compounds in lab-scale activated sludge systems performing nitrification and denitrification).   An early review of this topic, Refinement of biodegradation tests methodologies and the proposed utility of new microbial ecology techniques, explained: “We were also able to compare various processes and pointed out activated sludge with nitrogen treatment and membrane bioreactor as the most efficient ones.”  It seems we may one day learn how to design our treatment plants specifically to increase POP degradation.  Hold that thought!

Our choice of biosolids stabilization technologies makes a big difference. I won’t get into the effects of digestion here, which are significant in their own right, but I will admit that, for POP reduction, composting is one of my favorite stabilization methods. A large body of research shows how robust composting is for POP degradation.  The abundance of compost/POP research is in part because composting applies not only to biosolids but to the much vaster supply of animal manures, which like biosolids contain POPs. The good news is that fairly rudimentary composting techniques yield good results:  “low-level manure management, such as stockpiling, after an initial adjustment of water content may be a practical and economical option for livestock producers in reducing antibiotic levels in manure before land application ( Antibiotic Degradation during Manure Composting).

Compost/POP research also stems from the concern that compost is a consumer product, with a direct exposure pathway to humans. But compost has consistently shown strong results in mitigating risks.  For one paper (Organic Micropollutant Degradation in Sewage Sludge during Composting under Thermophilic Conditions)  concluded “concentrations of all 12 micropollutants decreased during composting, and degradation was statistically significant for 7 of the 12 micropollutants.”

Much of our Biosolids/POP research has been with the pathway of biosolids to soil to micro/macro fauna (including humans). Understanding the gaps in the research record on these pathways was an early WE&RF concern.  Trace Organic Chemicals in Biosolids-Amended Soils: State-of-the-Science Review provided the backdrop to the work that Dr. McAvoy now has underway. 

For the most part, the research record for many types of biosolids-borne POPs re-affirms the capacity of the land treatment system, consisting of soil minerals, organic matter and in synergistic relationships with microbial communities, to trap and degrade a wide range of POPs.  From among many dozens of recent journal articles in this domain, one review article, Plant uptake of pharmaceutical and personal care products from recycled water and biosolids: a review, concluded: “Field studies showed that the concentration levels of PPCPs in crops that were irrigated with treated wastewater or applied with biosolids were very low.”  In another pertaining to potential human health risks, “our assessment indicates that the majority of individual PPCPs in the edible tissue of plants due to biosolids or manure amendment or wastewater irrigation represent a de minimis risk to human health” ( Human health risk assessment of pharmaceuticals and personal care products in plant tissue due to biosolids and manure amendments, and wastewater irrigation ).  Nevertheless, in recognizing the enormous complexity of biological and chemical systems, “highlighting the significance of contaminant and soil properties in influencing risk assessment,” we must inevitably turn to risk modeling: A quantitative risk ranking model to evaluate emerging organic contaminants in biosolid amended land and potential transport to drinking water. 

Modeling may seem to be the poor cousin to comprehensive analytical investigations, but it may be the great way forward. Imagine a future in which you “dial-in” options for source control, sewer maintenance, in-plant processes, biosolids stabilization methods and land treatment protocols, all of which, when taken together, accomplish nearly complete removal of POPs from pathways of human and environmental exposure. To accomplish so grand an endpoint, however, means making POP degradation an intentional and central goal of biosolids management, not an incidental consequence.

How about we ”’POP’ the clutch” and accelerate our research into the fate of POPs through the entire treatment system and DRIVE THE POP OUT OF BIOSOLIDS.

Learning to be Proud!

This is a HUGE opportunity, posted just days ago, so act now!

“Teach Yourself Deep Learning with TensorFlow and Udacity.   Deep learning has become one of the hottest topics in machine learning in recent years. With TensorFlow, the deep learning platform that we recently released as an open-source project, our goal was to bring the capabilities of deep learning to everyone.”

Why wouldn’t everyone want “deep learning?” But what the heck is it?  It is what has Google rolling out driverless cars. It is what has medical imagining equipment more successfully identifying skin cancers than board certified dermatologists. It is what has operator-less wastewater plants working so well. Just joking about this last one. Google is providing inexpensive, often free training to the entire world. This is how exciting innovation is fostered globally!

I was on a search for great examples for on-line course work on the basics of biosolids land application, particularly videos. I found pitches for new centrifuges, and I found happy stories about biosolids use, particularly wonderful ones for Loop.  

But I did not find many detailed on-line instruction on best practices for production of good quality biosolids and for its application to land.  I did not find courses on biosolids use that were verified by course exams and documented with certificates of completion.  

I did, however, find many interesting, vaguely related stuff.

You can become a certified master gardener.  State universities throughout the MABA region offer coursework. Virginia Tech offers its Master Gardener Program, as do Extension Services for Penn State, Rutgers, Cornell and University of Maryland. But, if you want to learn to be a master gardener on-line, you need to go to the Pacific Northwest, of course, as in Oregon’s Master Gardener Online.

You can become a certified master composter.  The Master Composter/Soil Builder Program is an on-line program offered by Seattle Tilth, also from the computer savvy Pacific Northwest. Like gardening, each state and some municipalities offer compost certification.

Google is very distracting.  I found a slew of other fascinating on-line training programs.

You can become a certified master marijuana grower. Check out the Online Certification Course at CTU, that is the Cannabis Training University, and you can even work toward your Medical Marijuana Certificate, offered by the TMCIGlobal (The Medical Cannabis Institute).

How about a being a certified master beer drinker?  You can join the exclusive club of 2,500 Certified Cicerones; start your program by taking a free, 8 session online course on the chemistry of beer, and, can you believe it, you can work toward a certificate in beer and food pairing!

Wow! Mastering gardens, composting, marijuana and beer, from the comfort of your home and with a certificate to prove your accomplishment!

But what if you want to be a certified master biosolids manager?  This will take some digging.

A number of years ago a team of us worked with the Association of Boards of Certification to create the Land Appliers Certification Exam and a companion WEF/ABC Biosolids Land Appliers Guide to Preparing for the Certification Examination. But these tools and exams are not on-line and their use has languished.

The Water Environment Federation (WEF) is an important source of biosolids training, but mostly for managers and engineers.  WEF offers engineering type education, including a large number of “distance learning” modules, one which is Solids Handling, and for which engineers can obtain professional development hours, or PDHs. WEF also sells, for a rather steep $600 ($400 for members), its Biosolids Management Bundle, based on the Biosolids Environmental Management System (BEMS). This is a high-level, management type cut at biosolids practices, not qualifying for PDHs or CEUs.   The National Biosolids Partnership, now a program of WEF, produced a webcast in October 2012 called “BIOSOLIDS 101” -- Fundamentals of Practice. This is available for free view on WEF’s YouTube channel, the playlist of “Webcasts of the Month,” number 16 of 19, and offering 1.75 hours of PDH credits. You need to hunt for it by name to find it.  

Several states do biosolids land application training.  Of the seven states in the MABA region, biosolids courses are provided by the environmental agencies in two. Pennsylvania DEP has its “Land Application of Biosolids Training Course,” generally offered in classroom settings twice annually, and Virginia DEQ offers classes in “Biosolids Land Applicator Certification Training and Exam,“  both for initial certification and continuing education.  Field operators and supervisors in these states are required to undergo classroom training, and state coursework provides drilling on actions necessary for compliance with regulations. These courses are necessarily well attended by local operators, but they even attract practitioners from outside states. But they need to be in classrooms, which can be difficult for some operators to attend.

State requirements to maintain professional engineer licenses create demand for courses and training, biosolids one among many topics. These requirements may be met by attendance at professional conferences, including MABA’s, but a second avenue is online training.  One such avenue is provided by PDHOnline, an education firm that offers two biosolids courses. Both are presented by talented senior operator, Jim Newton, at the Kent (DE) County Public Works. These are: C267 Land Application of Biosolids/Septage and C402 Operations of Municipal WWTPs:Solids Processes, and each will set you back $200. Jim has been a prodigious course instructor, with a hundred or so in his quiver, most not in wastewater, ranging in length from one hour to eight, including one on co-digestion.

State universities provide limited biosolids training.  Most state extension services limit their outreach to issuing technical bulletins on field application practices (e.g., Pennsylvania’s on Biosolids Quality was pretty good, for its day, some 20 years ago).  Virginia has put some energy into a more modern, webinar-type instruction. Still available on a link through WebEx is Land Application of Biosolids, three one-hour episodes hosted and led by Dr. Greg Evanylo, covering the character of biosolids, aspects of potential environmental effects, and its use and management. I recommend the series, though it is rather simple, designed more for local officials than for practitioners.

I still have this underlying unanswered question: how are treatment plant operators and field application technicians getting their training? This important group, the very employees directly responsible for careful, compliant biosolids generation and utilization, are not served, at least not consistently, by convenient training opportunities. The Eastern PA Water Pollution Control Operators Association has two biosolids courses approved by the Pennsylvania DEP to meet continuing education unit requirements for operator licensing. But the courses are seldom held, and some of the volunteer instructors have retired.  Similarly, the Maryland Center for Environmental Training offers one course on “Solids Handling,” at its Harford County location, most likely handling in-plant topics.  

With the rapid growth of new, convenient training tools, we as an environmental practice ought to be doing better.  If we commit to a high level of performance in biosolids generation and utilization. with attractive, odor-free product, with landowners happy with productive soils, and supportive neighbors, we need a highly-trained and diligent workforce. Smart phones, webinars, on-line courses, customized feedback…  these are available widely in much of today’s world. How can we apply these tools to providing training for our workforce?

Why are we so late to the on-line training and certification? I have been told the most important missing element is the lack of state-level mandate for such training and certification. In today’s anti-government climate, it’s a far stretch to expect that to change any time soon. What we are left with is a need for inspired leadership for training coming from within our profession.

Marijuana growers and beer drinkers can muster this “professional” self-training, and I believe we can, too. Perhaps we need a clever marketing twist. Let’s call this program, for instance, the Certified Residual Application Professional.  C.R.A.P. could give us a reason to be proud.

Biosolids Goes Viral

Bacteria usually command front page, sort of the Donald of the microbe world. This week the Listeria bacteria powerfully disrupted Dole’s sale of bagged greens from Ohio (CDC: 1 Dead In Michigan From Listeria Linked To Dole Salads ), and several weeks back E coli shuttered Chipotle in various states, but particularly Oregon. 

But the more menacing of microbe stories this past week centered on viruses.

While Chipotle had its problem with E coli contamination, it also suffered from a virus, the norovirus, tied to unclean workers and food handling practices. Norovirus made ill a far larger number of patrons and workers than had E coli, not just in one locale, but in two, California and in Massachusetts (Chipotle’s Norovirus Outbreak Is Not A Typical Norovirus Outbreak ).

If you like this kind of stuff, you can’t beat the CDC reports of its investigations:  Vital Signs: Multistate Foodborne Outbreaks — United States, 2010–2014). (Hint: beware of organic alfalfa sprouts.) You can learn also of the viral causes of the over 100 million GI illnesses in the U.S. annually, particularly noroviruses and Norfolk-Like Viruses (NLVs).

Over the past two years, viruses clearly win the popular vote for health-scare. We had Ebola show its terrible rapid spread in 2014 into 2015. We in the wastewater industry have learned a bit about risks associated with discharge of human fluids to publicly owned sewers, and we have federal guidance to help us (Frequently Asked Questions (FAQs) on Interim Guidance for Managers and Workers Handling Untreated Sewage from Suspected or Confirmed Individuals with Ebola in the U.S.)  You  may have caught the news from WHO that “all known chains of transmission” of Ebola infections were closed (Latest Ebola outbreak over in Liberia; West Africa is at zero, but new flare-ups are likely to occur ). The next day the report came out that an Ebola case, an isolated one, had been reported. The world is not Ebola-free.

The latest viral scare, of course, is Zika. Zika is a mosquito-borne virus, like the better known West Nile Virus (WNV), but is scary for the horrifying birth defects and potentially debilitating paralysis. That it is not carried in animal, as is WNV in birds, will help limit Zika’s spread among humans in the United States.

This past week also witnessed another viral scare, an outbreak of avian flu in Indiana. The outbreak in Indiana was not the highly pathogenic avian influenza (NPAI) that resulted in loss last year of 48 million poultry and $3.3 billion, but a lesser pathogen.  Is there a risk to human health? We need to wait and see.

But we have increased viral risks from that great vector – stupid people. I found these two CDC reports of potential viral risks.  A New Jersey woman administered dozens of flu shots with the same unsanitary needle, and we had an NGO issue fraudulent rabies vaccine certificate to dogs imported to the U.S. from Egypt.

Stupid people seem to be the vector for water risks in Flint, Michigan., Yes, this is a lead issue, not a pathogen issue, but fundamentally the Flint story is about egregiously negligent government officials.  

Flint raises my biosolids guard.  With viruses emerging in prominence as world health issues, and with the failures of municipal utility management causing people serious harm, how can we in biosolids not pause to revisit our own responsibility for ensuring public health?  Are we sufficiently informed about connections between viruses in biosolids and human health risks, and do connect our choice of biosolids processes and practices to specific targets for viral pathogen reduction?  Are we witnessing a failure to advance the science behind biosolids pathogen and vector attraction reduction regulations? Have we ever witnessed biosolids folks doing stupid things? Yes, these are rhetorical questions.

If you haven’t reviewed the literature on viruses in biosolids over the past several years, you may not be aware of how rapidly our knowledge-base has increased about biosolids-borne viruses. 

Researchers have applied new DNA analytical tools to scan biosolids for a wide variety of virus types.  instead of focusing on a few potential indicators viruses, an array of viruses are measured.  The Yale University research team, headed by Dr. Jordan Peccia, in  Viral metagenome analysis to guide human pathogen monitoring in environmental samples , found “the RNA viruses parechovirus and coronavirus and the DNA virus herpesvirus were the most abundant human viruses in the biosolid sample tested here, [so that in the future we can] ensure that highly enriched and relevant pathogens are not neglected in exposure and risk assessments.” Their hope is that “as the costs of next-generation sequencing decrease, the pathogen diversity described by virus metagenomes will provide an unbiased guide for subsequent cell culture and quantitative pathogen analyses and ensures that highly enriched and relevant pathogens are not neglected in exposure and risk assessments.”

Treatment processes don’t necessarily serve as adequate barriers to all pathogens. For example, the Yale team, in  Survey of Wastewater Indicators and Human Pathogen Genomes in Biosolids Produced by Class A and Class B Stabilization Treatments, reported that in biosolids composting systems Legionella bacteria seemed have the potential to proliferate during composting to thrive in biosolids composting processes.”  The authors also argued that “we can translate these infectious adenovirus concentrations in bulk biosolid samples to a downwind aerosol concentration using a previously described and calibrated aerosol transport model for respirable biosolid material at off-site locations.”

The Yale team’s results also offer ideas for improving regular monitoring of biosolids products.  The paper stated that in “…a cross section of biosolid samples (Fig. 1), male-specific coliphages appear to be a more stringent test of inactivation.  …pathogen concentrations for a given sample were more comparable to male-specific coliphage values; this result suggests that they would be more useful for documenting pathogen presence than fecal coliforms.”  In another recent journal article by this team, Identification of viral pathogen diversity in sewage sludge by metagenome analysis, the authors recommended that the industry should “consider a broader selection of viruses in environmental fate and transport studies, and importance of considering multiple human exposure routes to sewage sludge and wastewater.”

The EPA lab in Cincinnati has contributed recently to the evolving science of measuring viruses.  Eric Rhodes, head of the team at USEPA Cincinnati Labs, authored a recent article Determining Pathogen and Indicator Levels in Class B Municipal Organic Residuals Used for Land Application.  Dr Rhodes writes: “Overall, this study reveals that high concentrations of enteric pathogens (e.g., Cryptosporidium, Giardia, and HAdV) are present in biosolids throughout the United States. …. A more thorough analysis of the relationship between pathogenic HAdV and fecal indicator organisms is warranted. Nonetheless, these results reveal the potential risks associated with exposure to human adenovirus and protozoan pathogens present Class B treated biosolids.”

Research results that enumerate viral organism in biosolids provide inputs to new tools for assessing health risks and for decision making. A Swedish research team headed by Robin Harder published  Including Pathogen Risk in Life Cycle Assessment of Wastewater Management. 1. Estimating the Burden of Disease Associated with Pathogens , followed by Including Pathogen Risk in Life Cycle Assessment of Wastewater Management. Implications for Selecting the Functional Unit. This team conducted an evaluation “based on eight previous QMRA (quantitative microbial risk assessment) studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.279 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 287,600 persons and for the pathogens and exposure pathways included in this study.”

Yes, a lot of new science and new assessments. This deserves our attention and, what is more, even in the absence of EPA funding, it deserves investment of our money. The pay back might be most keen in providing incentives for companies to evolve treatment technologies and for public agencies to institute best practices. The pay back is also in our pride when we well-serve our ratepayers and communities.  And, best of all, it may remind us Don't Be Stupid.  

Digesters on a Low-fat Diet

The maintenance manager at Landis Sewerage Authority was quite graphic in his description of the fibrous mess in his digester’s sampling port. Landis has been accepting FOG (fats, oil and grease) and liquid HSOW (high strength organic wastes) for about a year.  The operators believe rags are coming in with restaurant grease trap wastes. These are ground up at the liquid waste receiving station, and, once in the digester, the rag fibers have attracted grease and human hair. The maintenance team had seen these fibrous grease balls clogging the sampling port pipe, congealed into an indurated, hairy mess.  The pipe had to be cut out, and the manager intended to make a cross-sectional cut of the pipe for illustrative purposes. He hadn’t seen a mess quite like this before Landis had begun accepting the wonderful FOG and HSOW that had allowed its digester to nearly double biogas production.

Hmmm, this is a downside of co-digestion that I hadn’t heard articulated so graphically – raggy, hard grease balls.  I had for many years listened to operator stories of mysterious mop heads in digesters.  But the clog in the Landis digester pipes seemed a particularly nasty version of these.

I recalled a 2010 presentation by Virginia Tech professor, now emeritus, John Novak, about the complexity of oils and fats and their fate in mesophilic anaerobic digesters.  This was a presentation to the Mid Atlantic Biosolids Association specialty conference on co-digestion substrates in 2010. Dr. Novak made the point in his presentation, “Codigestion at WWTPs – Digester Operations,” that not all grease is good for biogas production in digesters. Specifically, certain heavy lipids (chains of 16 and 18 carbons of saturated and mono-unsaturated fats) resist digestion, are difficult to solubilize in digesters, and may exert toxicity. Meat-sourced oils (forming stearic acid) and favorite cooking oils such as palm and coconut (forming palmitic and myristic acids) are just such long-chain saturated fats. These oils degrade into fatty acids that agglomerate and form “micelles,” or what are more commonly known as grease balls. A fatty acid such as stearic acid can then saponify (form a soap) and, in the presence of calcium ions, become hard, greasy lumps, long before microbes can convert the fatty acids into biogas. 

The sources of saturated fats that clog our digesters are the same staples in the American diet that clog our arteries – pizza and burgers, garnished with cheese, bacon and sausage.  You can see this in a table of the sources of stearic acid.  

While the biochemistry of the different fats in wastewater operations is not well understood, the subject is now gaining research interest, as in “Anaerobic co-digestion of fat, oil, and grease (FOG): A review of gas production and process limitations.”  This work was done at a laboratory of Dr. Francis L. de los Reyes III,  at North Carolina State University, whose paper observed: “anaerobic digestion of high lipid wastes has been reported to cause inhibition of acetoclastic and methanogenic bacteria, substrate, and product transport limitation, sludge flotation, digester foaming, blockages of pipes and pumps, and clogging of gas collection and handling systems.”

Clogging…. This is an essential issue for Landis. For all of the trouble that grease balls and mop heads present to wastewater operations, I am curious that they receive very little scientific and engineering attention.  And the role of rags in the formation of grease balls and mop heads has been barely noticed in the technical literature.  A word search of the WEF Manual of Operations on solids treatment came up with not a single reference to rags.

To my delight, the same Dr. de los Reyes who is researching the digestion of lipids has done some works with rags.  He practically stands alone in this field of research, testimony perhaps to how hard it must be to find engineering graduate students with senses of humor sufficient to study the physiochemical behavior or rags and grease in wastewater. But they do have a recent landmark study of sewer collectors, in which rags play a big part: Evidence for Fat, Oil, and Grease (FOG) Deposit Formation Mechanisms in Sewer Lines.

Our treatment plant operators are experts on what typically happens when rags get to the plant in the influent stream.  If the way treatment plant operators manage rags is to trap as many as possible on headworks bar screens, then to catch the rags that get through the screens within the scum collectors, or then to unwrap the rags loose from bars and chains in the treatment tanks, what happens when the rags ultimately get into the digesters?  Not much, except to presume they reside in the digester, gathering together with hair and grease to form mop heads, until the next digester cleaning.

If in accepting liquid wastes directly into the digesters your agency is thereby bypassing those several rag-trapping steps between the headworks and the digesters, how are you handling the rag challenge?  Aren’t you asking for a good deal more rags and fibers in the digesters than is typical in wastewater operations? Do we sufficiently understand how rags and fibers react with oils, grease and hair to know if we can take steps to avoid excessive grease ball formation and clogging?  

This is where real-world experience counts.  Derry Township, Pennsylvania, has been taken in high strength wastes for a decade. It’s not hard to get Executive Director Wayne Schutz to bottom-line his advice: “NEVER, EVER, EVER feed that FOG stuff directly to the digester!!!  Aerate, mix, chop, and bio-augment to break the long chains VFAs; do a pH adjust; screen, de-grit, settle, grind, macerate, chop and macerate again; then feed to digester!!”

Dr. Novak offered in his 2010 presentation several ideas about the grease balls.  He suggested that those agencies looking at trucking in HSWO containing long-chain oils consider deploying advanced digestion, such as acid-phase digestion and/or thermophilic digestion. He recommended vigorous digester mixing, to help break up the agglomeration of grease balls.  He believes that microbial communities will, over time, acclimate to the character of the feedstock to digesters, so plant managers ought to work toward lining up steady, consistent sources of HSOW. But, as Landis Sewerage Authority has discovered, this can be a difficult task in the dog-eat-dog world of waste haulers, for whom a fraction of a cent per gallon lower disposal price down the street has them drive past the reliable neighborhood treatment plant. 

If your digesters have gotten filled with grease balls and mop heads, what can you do?  I spoke to Dr. de los Reyes about the challenges of rags and oils in digesters. He noted the difficulty of projecting from lab-scale digesters the behavior of the full range of FOG in full-scale sludge digesters: “Once the structure is there, it is difficult for the bugs to get to the grease.” He has been examining approaches that include increased digester mixing, microbial community acclimation, bio-augmentation and biodegradable detergent supplementation to see if such tailored strategies might deal with the challenge of grease balls and mop heads.  But his most effective tool is old-school: “What I see is digester shut downs and companies coming in to pump it all out.” 

There you have it. If you take in an assortment of FOG and HSOW, be prepared for frequent digester cleaning.  For our anaerobic digesters, healthy co-digestion means Digesters on a Low Fiber Diet.

Closing the Circle with Biosolids

The “virtuous circle” is what I long ago termed the recovery of resource value from biosolids, so self-evident to me is the wisdom of our biosolids recycling enterprise. I bookmarked in my browser the Ellen McArthur Foundation’s Circular Economy website a decade ago, so immediately compelled I was to see a connection to our biosolids profession's mission of environmental stewardship. Two years back I wrote a piece on biosolids as part of the circle of life, starting out with a quotation from New-Age philosopher Deepak Chopra. I have a website launched to celebrate the “gospel” of biosolids recycling, The Resource Circle, and, even though I haven’t promoted it with a full-out effort, the site has already attracted a few detractors.  You see, I am “all in” with this "circle" concept.

You can imagine my instant interest, then, in the front cover feature of the June 27th issue of Chemical & Engineering News --”Closing the loop on material recycling: Big brands and regulators seek to jump-start the circular economy.”  While one article dealt with challenges faced by brand-name clothing manufacturers, the pertinent article for our profession is “Europe circles the circular economy,”  

While the U.K. and the European Union have a vigorous political dialogue underway with Brexit, between its chemists and environmentalists is a vigorous science debate on how to implement a Circular Economy.   The European Commission launched in January 2016 its “Circular Economy Strategy,” in a public summary report entitled Closing the loop: New circular economy package. 

This initiative has very ambitious goals for 2030. One of these, to my mind, has “biosolids” written all over it: “The action plan for the circular economy aims to 'close the loop'…. This production and consumption model is based on two complementary loops drawing inspiration from biological cycles: one for 'biological' materials (which can be decomposed by living organisms) and one for 'technical' materials (which cannot be decomposed by living organisms). In both cases, the aim is to limit the leakage of resources as much as possible.”

We, especially, don’t want biosolids leakage.

The tagline to the C&E News article was particularly provocative. It said: “Tempers flare over how to deal with hazardous chemicals in closed loop systems of the future.”  The “flared tempers” have direct parallels to biosolids issues.

The article reported:  “Environmental activists say the 169 substances of very high concern, which include some phthalate plasticizers used in flexible PVC, that are already controlled under the EU’s Registration, Evaluation & Authorisation of Chemicals (REACH) chemical management law, should be automatically excluded from recycling systems under any circular economy legislation.”

The person representing chemists at the Helsinki Chemicals Forum in Finland is Peter Smith, executive director of product stewardship for the European Chemical Industry Council.  He said: “The devil is in the details…”  The article points out that “one devilish detail is which chemicals would be included in closed-loop recycling systems and which would be excluded on grounds that they present an unacceptable hazard to society.”  In Helsinki, Smith argues “Inclusion or exclusion should be made on a case-by-case basis by looking at costs and benefits.” The environmentalists yelled back, literally.

Herein lies the dilemma. Can there be an a priori sorting of good versus bad chemicals in products present tin today’s marketplace which dictate which loops are closed and which are not? Is biosolids in or out of the loop-closing exercise when such a priori choices are made?

I say they are well within the loop based on sound science.  From a public policy and opinion basis, and perhaps even from a science basis, the answer is still an open  one.

Work still lies ahead to close the loop regarding the effect of chemicals on loop-closing projects.  Europe’s Commission says the loop-closing effort needs to meet three simultaneous conditions:

1. Manufactures and government need to show they can adequately “characterize the health and environmental effects of thousands of chemicals, with new molecules constantly being developed.
2. ”Regulators and policy makers need to “…create market signals and framework conditions that will encourage rapid adoption of new technologies and practices.”
3.  Government and business need to activate in the market place for “sustainable consumption on a large scale.”

The European community has jumped out ahead on this project of almost mind-numbing complexity. Where is the U.S. in all of this?

While environmental policies have not been so clearly framed in terms of loop closing, a few such compatible initiatives live in the U.S.   To advocate for the design of sustainable “green products,” the Product Stewardship Institute brings together manufacturers, the waste industry and government. One of PSI’s advocacies is for adoption in the U.S. of a 15-year-old European initiative called Extended Producer Responsibility (EPR) laws. PSI is thinking pharmaceutical take-back programs, for instance -- a good thing for those of us who see the consequence of drugs flushed to the sewer.  To promote use of sustainable products, the Sustainability Consortium, constituted by many trade associations, large manufacturers and a few “civil society” organizations, claims “Members play an essential role in helping us get closer to achieving our mission to improve sustainability of consumer goods at scale.” It would be great for our industry when, for example, flame retardants and anti-bacterial compounds are phased out of use.  To create a commercial marketplace, Sustainable Purchasing Leadership Council, supports procurement standards for green products.    

How can the biosolids profession get into the loop-closing game?

What if we biosolids practitioners were to join the “closing the loop” movement by demonstrating that biosolids are a part of the emerging “bioeconomy,” in contrast to the “fossil economy.” We, too, could help produce fun videos explaining how our biosolids-based products are good for communities and the environment, as the Brits did with the YouTube animation “The bioeconomy starts here!”  We, too, could get our biosolids-based materials classified as a “biobased products,” or perhaps even designated by the USDA as “biopreferred.”

What if we leaders of the nation’s wastewater systems were, with a coordinated voice, to take part in the “activation of sustainable consumption on a large scale”? As organizations that serve every flushing customer, which is everybody, we could ask them to choose products and practices that improved the quality of their community’s biosolids, earning them the privilege to “close the loop.”  

To date we have been strangely silent in the kind of debate that was reported in Helsinki of how to deal with persistent pollutants, but we can reverse that silence, and put ourselves on the side of the activists as beneficiaries of reduced use of persistent organic chemicals in consumer products.

We need New Ideas to Close the Circle.