What New in Biosolids Research


Sally Brown contributes monthly summaries of research topics pertinent to biosolids and sustainable wastewater management

Dr. Brown is helping out here.  While not a new topic for her, many of us had not been paying attention until NEBRA's Ned Beecher called the alarm for a regulatory threat arising in New Hampshire for the future of land application. That threat is tied to PFOAs (perfluorooctanoic acids), or more generally to the class called PFAS (perfluoroalkyl substances), "emerging" as a compound of human health concern. These compounds arrive in biosolids from consumer products and tapwater; they do not degrade; and when placed on the ground, some portion can migrate to groundwater. Not what we want to know.  Many new science articles are appearing, and Dr. Brown gives us an overview.

FEBRUARY 2017 RESEARCH UPDATE

Dr. Sally Brown revisits an old friend of mine in her February Biosolids Research Update. Well, not really a friend, but a chemical I lived pretty close to and grew very familiar with back in 1993 when Phildelphia's biosolids program was upended by a large illegal discharge of polychlorinated biphenyls. Dr. Brown recently reviewed the topic of PCBs in biosolids. This follows from a call of a concerned citizen out in western Washington from a recently published journal article on risks of PCBs in biosolids. She read some key assumptions in this new paper that sent her back to original journal articles. The bottom line is that, no, PCBs are not compounds of significant concern in biosolids today. Read Dr. Brown's blog on how she can be so confident in this position.

DECEMBER 2016 RESEARCH UPDATE

Dr. Brown serves up a Holiday Greeting, a blurb of thankgiving to the wonderful work of wastewater treatment and biosolids practitiones in providing safe and clean water, and serving to improve soils. Hers is an endearing note. And Read Dr. Brown's Thank You to Biosolids Practitioners.

NOVEMBER 2016 RESEARCH UPDATE

Dr Sally Brown is concerned with our expression, the way we speak, and how that reflects our thoughts. She responds in this blog to findings, reported at the NBMA BioFest, of the public knowledge of and interest in biosolids topics. The advent of social media is providing a whole new way to understand, almost in real time, the formation of attitudes and judgments, and our realization of these factors will help us better communicate. Read Dr. Brown's Blog on why we must not use the "D" word.

OCTOBER 2016 RESEARCH UPDATE

Dr. Sally Brown's October Research Update reports on a light-hearted presentation from the Northwest Biosolids Management Association's Biofest in mid September. Her argument underscores the need for a balanced viewpoint of risks and exposures in the interpretation of scientific results, at the juncture with policy. The lessons learned in the work of the last generation on trace element chemistry in soll-plant interactions are relevant to the study of residues of pharmaceutical products, Brown argues. More importantly, we need to guard against the alarmism that the hunt for research money engenders. Read Dr. Brown's Blog on Science of Micropollutants here.

SEPTEMBER 2016 RESEARCH UPDATE

Dr. Brown frames for us in this month's blog the issue of food waste in the U.S., and its extraordinary financial and environmental cost to society. And, of course, her interest is in how the solution to this issue of increasing public awareness may be solved by initiative at our public wastewater treatment works. Most of us know that the interest in "co-digestion" has grown strong in our conference gatherings and among policy leaders. Sally reaffirms in her selection of research articles to review this month the exciting potential of anaerobic digestion facilities as a low-cost, high benefit solution for communities. Read Dr. Brown's blog on food waste management here.

AUGUST 2016 RESEARCH SUMMARY

The August resaearch summary is an overview of Dr. Chaney's work with cadmium, one of the key elements of concern at the dawn of biosolids regulations in the 1980s. Dr. Chaney showed the importance of the biosoldis matrix in influencing the biochemical reactions of biosolids in the environment. He also drew the connection between dietary balance of elements and the potential for absorption of pollutants. This is great work, for which the honors given Dr, Chaney in his career are so well deserved. Read Dr. Brown's blog on her mentor's work here.

JULY 2016 RESEARCH SUMMARY

In the July Research Update, Dr. Sally Brown brings us words of joy and comfort, if you are a fan of carbon sequestration and biosolids recycling. She explains that scientists now understand that stable increases to the reserve of organic carbon in soils are not due alone to the amount of carbon amendment added to the soil, but to the overall balance of nutrients added along with the carbon. Without those nutrients, carbon doesn't hang around. You guessed it, biosolids provides that kind of balanced nutrition favoriing a permanent kick upward in soil carbon. This is great news, for biosolids and carbon sequestration as a greenhouse gas mitigation tool.To read Dr, Brown's blog, click here.

JUNE 2016 RESEARCH SUMMARY

Dr. Brown introduces the concept of soil microbes as the "highly exposed individuals" of concern to risk assessment in the use of biosolids. The bottom line is that biosolids doesn't effect soil nearly as much as the act of farming itself. But between that conclusion and the question of soil microbial communities, we realize a very complex world exists about which the new tools of genomic analysis is just opening to our understanding. To read Dr. Brown's blog, click here.

MAY 2016 RESEARCH SUMMARY

Sally takes on the biggest of all environmental stories in the press today, that of the element lead, especially the issues raised by exposures in Flint, Michigan. She reviews for us the chemistry of lead that makes our water infrastructure vulnerable to lead releases, and how that can translate into exposure to humans, with the most serious exposures being young children and their developing brains and nervous systems. The issue has been cast in Flint as an environmental justice issue, but the truth is that all water systems need to have integrity in their treatment and distribution system management. For her blog on the topic, click here.

APRIL 2016 RESEARCH SUMMARY

Dr Brown gives us her favorite topic, the use of biosolids to reclaim scarred minelands. She draws on the seminal work of her mentors long-ago in the 1970s, including early work in Virginia and Pennsylvania, and then to work by Chicago and agencies in the State of Washington, now her home state. While the issues over the years has shifted, from a focus on metals to now persistent organic compounds, what has not changed is the astonishing results of the reclamation work in restoring soil. For that result we can all be proud and take home lessons. To read her blog, click here.

MARCH 2016 RESEARCH SUMMARY

Dr. Sally Brown's essay this month is about one of the microconstituents of the day -- PFOAs. We need no reminding that biosolids is reservoir for persistent chemicals in widespread use in commercial products. In this case, the chemical is perfluorinated organic compounds, your non-stick chemical additives. They have been in widespread use for many decades, but relatively recently have scientists sought to detect their occurrences throughout the biosphere. And, yes, they are everywhere, including biosolids. But that does not mean that the biosolids constitutes a significant source or environmental risk. In this review below, Dr. Brown provides a commentary on useful research abstracts, any one of which I can help you obtain. You can read her blurb here.

FEBRUARY 2016 RESEARCH SUMMARY

Dr. Sally Brown's essay this month is a "back to basics." That is, she review the fundamentals of the use of biosolids as a source of nitrogen fertility for crops. As she points out, the biochemistry of nitrogen in the soil matrix is complicated, and it is a core aspect of our work with biosolids that we use the best information available from her cited publications to meet farmers's needs and prevent unnecessary losses. Dr. Brown's message is a reminder to me that deploying biosolids-borne N makes sense as a sustainable practice for protecting Earth's environment. To read her blurb, click here

DECEMBER 2015 RESEARCH SUMMARY

Dr. Sally Brown provides us an essay that appeared in the November 2015 BioCycle. She leaps into a long comparison of the loadings of contaminants in biosolids used for vegetable production to the loadings that a fictional character of a recent Matt Damon movie would have experienced in recycling his own pee and poop. The challenge for our industry is to have our recycling stories come across as compelling as this Martian survival story. To read Dr. Brown's blurb, in a BioCycle reprint, go here.

NOVEMBER 2015 RESEARCH SUMMARY

Dr. Sally Brown is taking on biosolids-borne pharmaceuticals. This focus arises from media attention to a recent article in Engineering Science and Technology that asserts plant growth impacts from anti-epileptic drug uptake by vegetable crops. As was so customary back in the days of heavy metal research, the scientist used extraordinarily high concentrations, used the compounds in their pure formulation, absent biosolids, and then lept to unsupportable conclusions regarding potential effects from biosolids. This absolutely has Dr Brown at her most focused and incisive review. To read her blurb, go here.

OCTOBER 2015 RESEARCH SUMMARY

Sally takes a look at the research of fear. WHy is this? Well, despite an aggresive program of public outreach and education, there is heat in the Northwest. Again, why is this? A familiar story -- a mismanaged contract with a low bid cotractor and no genuine mechansim to conduct publid outreach. It turns out much is know and much is knowable about what works and deosn't work in dealing with public communications. Why is it that we don't seem to learn? Sally doesn't really answer that quesiton, but here research summary gets at some important points, so click here.

SEPTEMBER 2015 RESEARCH SUMMARY

Dr. Sally Brown recommends Mork & Mindy reruns. You can find them on Hulu. She is revisiting the issue of nano particles in biosolids and their potential risk to the soil and plant environment via the biosolids exposure pathway. Her concern is that a reputable journal, the Journal of Environmental Science & Technology, published companion papers that seem to point to a significant effect. But the sticky wicket is that the method of simulating wastewater treatment is so flawed as to mirror the errors made a generation ago in presuming metal salts behaved the same as biosolids-borne metals at the soil-plant interface. In the case of nano-materials, as in metals, they plain don't. So you might as well spend your time with "nanu-nanu" with Robin Williams as with "nano-nano" in these journal articles, as at least Williams is fun. To see Dr. Brown's comments, click here.

AUGUST 2015 RESEARCH SUMMARY

Dr. Brown deals with the metaphysics of microconstituents. She notes that some scientists in this arena of research seem to found their work on a premise that any imprint of human-made chemical is unacceptable, presuming that one only need to continue searching deep and long enough and dire effects will be revealed. For another group, they look for the clear evidence of harm and suggest that until such is demonstrated we should call no unnecessary alarms. A third group says we need to be smarter in the future in projecting fate of new chemicals before introducing them to the environments. No one way is best. Scientific tools are rapidly advancing to allow us to hold anyone of the three metaphysical positions and engage in useful research. But the work needs to proceed. See Sally's blurb here.

JULY 2015 RESEARCH SUMMARY

Dr. Brown confronts head-on a kind of scientific naivete regarding the treatment and use of biosolids. If I were more pessimistic by nature, I would wonder if an intention to mislead was behind some of the representations made about the consistutents of biosolids. But if you stand back, squint a bit, you might see the point that, over the long haul, the resources that are "conservative" after human use can be recovered, and those that are "decomposable" can be transformed. This aligns with The Natural Step prnciples (Google it...). And the ideas align with the concept of resource reusie. See Sally's blurb here.

JUNE 2015 RESEARCH SUMMARY

Dr. Brown takes on one of the most serious of all global environmental issues, that is the discharge of reactive nitrogen and phosphorus from agricultural activities and wastewaters. The concept that is explored is the role of treatment and waste recovery strategies for capturing and repurposing nitrogen and phosphorus to protect environmental quality and reserve resources for future generations. These concepts provide a huge and significant context for the work we biosolids managers do on a daily basis. They give us the language to explain the vital aspects of our goals. See Sally's blurb here.

MAY 2015 RESEARCH SUMMARY

Dr. Brown provides this month a primer on microplastics. It is the newest pollutant category about which you have never heard, about which you can easily imagine disaster, and about which scientists are still baffled about its potential effects. These are very, very small plastic beads used to in cosmetics and clothes, which mean they get flushed down the drain daily. Some get in the biosolids, some stay in the effluent., When you start to look for them, you can find them in aquatic systems and soils at biosolids application sites. They seem to be ingested by aquatic microfauna, but whether this is a crisis for the bottom of the food chain is a question still being explored. These are the subjects of this month's updates. See Sally's May blurb here.

APRIL 2015 RESEARCH SUMMARY

Sally flies above the banal biosolids issues to survey the country's water infrastructure challenges. The nation's treatment systems are deployed to do much more than they were in the past designed to do, including storm water pollution control, treatment for water reuse, supplementation of stream flow, removal of trace chemicals, and other enviromental services. What are the costs and benefits of such services, and how can reinvestment in infrastructure contribute to social and economic beneifts? These are some of this month's topcs in the research updates. See Sally's April blurb here.

MARCH 2015 RESEARCH SUMMARY

Sally takes on our own version of the "merchant of doubts." My cultural reference here is to the new movie who features the well-paid craftsmen whom in the past brought us stymied anti-tobacco regulation a generation ago, and whom in the presence stymie action of greenhouse gas emissions. Sally, without the benefit of the new movie, explores research into the mechanisms by which vaccination-deniers have peddled falsehoods about risks of MMR(Measle, Mumps and Rubella) vaccinations. The results of the intentional misinformation on risks is real public health issues. We face the same kind of misinformation campaigns, but the task in front of us constitutes a very formidible one. See Sally's blurb here.

FEBRUARY 2015 RESEARCH SUMMARY

Sally takes up again metals. She reminds us that that the issue of high metals carried in biosolids is an historical one. Today's biosolids bears closer resemblance to manure and food in its profile of metals. Two important reminders is that the organic and mineral matrix of biosolids holds metals agains environmental and some of the metals are valuable necessary nutrients. See her blurb here.

DECEMBER 2014 RESEARCH SUMMARY

Sally takes on the Whole Foods mind-set again. That is, she takes on Whole Foods for its unfounded presumption that animal manures used in "organic farming" comprise acceptable risks compared to biosolids. A primary area of concern is the issue of known risks from pathogen transmission from manures. Pork is a leading culprit. That animal production is increasingly international and feedlot based has raised risks. Biosolids ought to be the least of Whole Foods worries. See her blurb here.

NOVEMBER 2014 RESEARCH SUMMARY

Sally is inspired by Whole Foods wholely mis-guided biosolids policy to make the point that USDA Organic Rule fails to stand up to scrutiny as the "gold standard" for food safety. She points out that, for the most part, biosolids would be by far the safer alternative for use in growing vegetables. This is the first of several reviews Dr. Brown will provide on the subject of biosolids vs manure and the extent of mis-guided policies that have evolved. See her blurb here.

OCTOBER 2014 RESEARCH SUMMARY

Sally reviews the genesis of nitrosamines. One of the health scares that proved, with more research, to not be so scary was nitrites in cold cuts and bacon, a chemical that tamped down botulism. Nitrite converts to nitrosamines, and nitrosamines are believed to be carcinogenic, so the fearsome notion was that bacon causes cancer. Well, all said and done, USDA regulated nitrite additions, and now the concern with bacon is its other properties. But that doesn't keep some researchers, specifically the one that brought the triclocarbam issue to us, to suggest that nitrosamines in biosolids warrants gobs of research dollars. Check out Sally's research summary, and particularly her blurb here.

SEPTEMBER 2014 RESEARCH SUMMARY

Dr Brown uses Toledo as a "teachable moment" about the priority attention for nutrient sources to our lakes and rivers. The attention must be given to agricultural practices. She argues that the kind of compelling regulatory frameowrk that has accomplished a transformation in municipal wastewater treatment practices has been missing if agriculture. The impacts of that vacuum plays out in Toledo's algae bloom, as it continues to do in the Gulf of Mexico dead zone. The next time that biosolids recycling is singled out for attack, be prepared with the kind of big picture assessment we are given in Dr Brown's blurb here.

AUGUST 2014 RESEARCH SUMMARY

Sally takes us down the worm hole this month. Earthworms are a favorite companion of soil toxicologists seeking to understand how persistent pollutants flow through the environment. While studies show that fertility and tilth improvements arising from biosolids applications stimulate worm growth, how can we be sure that those next trophic levels consuming worms are not providng pathways for exposures to compounds contained in the biosolids. So, here we go. The research seems pretty good for our team, but you better check for yourself. Read Dr. Brown's blurb here.

JULY 2014 RESEARCH SUMMARY

Again, a commentary on the "micro" constituents in biosolids. Dr. Brown takes us to a few special investigations into the presence in urban wastewaters of compounds derived from illicit drug usage. I suspect easier ways exist for surveying illegal drug trafficking, particularly as the transformations of chemicals within the human body, through the sewer and through the treatment process are not well known. What is more, the mere presence in the biosolids or effluents do not lead to any particular understanding of adverse effects on the environment. So, what does it all matter? But sometimes we can't predict the outcomes of science pursued for its own ends. Read Dr. Brown's take on the issue in the blurb here.

JUNE 2014 RESEARCH SUMMARY

This month, like the last, the hot topic in biosolids is the fate during wastewater treatment system of organic compounds manufactured for use in personal care products, in clothing and furniture, and in pharmaceutical drugs. But this is the special case in which biosolids are composted, thereby subjecting these compounds to the microbes and heat of composting. This helps to answer the question whether composting can reduce organic compounds in the product. Read Dr. Browns blurb here.

MAY 2014 RESEARCH SUMMARY

This week Dr. Brown brings our attention back to compounds of concern (COCs). Four of our papers this week shed light on an unfortunate story. Compounds such as Triclosan (TCS), 4 nonylphenol, 4-t-octylphenol and bisphenol A degrade in soil, but at slower rates than previously expected. Our final paper forces us to ask ourselves (and others) the question, isn’t it time we look at why we are using antimicrobials such as TCS and TCC in our household (soap and toothpaste)? Aren’t there safer alternatives? We all know biosolids provide countless benefits so wouldn’t it be a win-win for activists to fight against having the COCs in items we come into contact with every day? Read Dr. Brown's blurb here.

APRIL 2014 RESEARCH SUMMARY

Dr. Brown explores the "science" of communication science. The bottom line is grim. We might believe the message "sound science" sells when we shout out why biosolids is good. But this doesn't play with the public. You don't need to go much further than the most recent story about the fate of carbon dioxide and methane emissions regulation to see how science is a "non-starter." Interestingly, one message is that we need to frame different messages for different people if we are to have a broad impact. Please read Dr. Brown's blurb here.

MARCH 2014 RESEARCH SUMMARY

Dr. Brown takes aim at what is apparently an incomplete scientific examination of the effects of persistent organic compounds that was widely published by researchers at Duke University. The subject was the effects of triclosan and trichlocarban, two antibacterial compounds that have become widely used in consumer products and that can pass to biosolids, and, hence, to soils. As Dr. Brown shows, by lining up a series of other peer-reviewed articles, the Duke University researchers seem to have let their prejudgment of biosolids cloud their interpretation of their results and also their thoroughness in reviewing the scientific article. You can read her blurb here.

FEBRUARY 2014 RESEARCH SUMMARY

With only a single month break during the holiday season, Dr. Brown returns to tackle the so very complex arena of persistent chemicals in the class that includes flame retardants, waterproofing, non-stick surfaces. These are the perfluoroalkyl acids, a class that can be extremely varied in their formula. What makes them unusual is their ubiquity in clothing, furniture and packaging, such that their release to the environment from mulitple sources is practically a foregone conclusion. And while hope had been held that the substances would proof resistant to mobilization through soil and plants, the story is much more complicated. It is important to read Dr. Brown's blurb here, as it helps to pull this complicated topic together for easy soundbite.

DECEMBER 2013 RESEARCH SUMMARY

Dr. Brown draws on the work of a University of Washington PhD student, Caitlin Youngquist to look at recent research in the engagement of citizens in managing risks of undesirable land uses. The message is that professional credibility is earned through a communication process, and that a genuinely open process of soliciting input, done with an eye to genuine two way dialogue, can yield good project results. Read the blurb here.

NOVEMBER 2013 RESEARCH SUMMARY

Dr. Brown enters the stormy world of sewers to explore ways that biosolids can be part of evolving "green infrastructure" solutions that many cities are considering for solving their Combined Sewer Overflow situations. Her review shows that bioretention facilities are among the effective green options. For these to work, designer soils are needed. Research reports she summarizes suggests that biosolids-based soil products can be important ingredients for soils in bioretention basins. Read Dr. Brown's November Blurb for her take on the role of biosolids in green infrastructure.

OCTOBER 2013 RESEARCH SUMMARY

This month, Dr. Brown takes us on a tour of reports on surveys of public acceptance for biosolids recycling. Transparency, credible health effects information, agency reputation are among the positive attributes supporting positive public opinions. In the bottom analysis, very few programs seem to successfully support public opinion through demonstrating the positive plant growth results that biosolids produce. Read Dr. Brown's October Blurb for a global view of biosolids recycling acceptance.

SEPTEMBER 2013 RESEARCH SUMMARY

Dr. Brown looks at recent literatura on biochar produced from biosolids or used in conjunction with biosolids. One of Dr. Brown's observations is that thermal processes producing biochar cause a loss of N. While the interaction of soil, nutrients, biosolids and biochar are very complicated and hard to generalize, one phenomenon that seems to bear out is the capacity of a blend of biochar and biosolids to retain applied nitrogen within the soil. Read Dr. Brown's September Blurb to better understand this complicated research area.

AUGUST 2013 RESEARCH SUMMARY

This month Dr. Brown takes on antibiotic resistance. This is an area of environmental affect that has Dr. Brown concerned, but the concern is mostly with the big boys, the producers of animal manure and health wastes. But that doesn't let wastewater facilities off the hook. The choice of treatment technologies and application techniques can affect the fate of genes entering the environment that alter the expression of microbial resistance to antibiotic compounds. Read Dr. Brown's August Blurb to learn more.

JULY 2013 RESEARCH SUMMARY

Sally Brown gives us a summary of her search of the world's peer-reviewed literature for "triple bottom line" analysis of biosolids management programs. The "bottom line" was that there is not much out there, not even for the overall wastewater treatment system. Biosolids present some unique challenges, which Dr. Brown underscores in her commentary. Also, she discusses the work of one of her graduate students in understanding the flows of material and energy as they can be tallied in this accounting system. Read Dr. Brown's view on this in her July Blurb.

JUNE 2013 RESEARCH SUMMARY

This month Dr. Brown provides recent scientific studies of the fate of a common pharmaceutical compound that resists decomposition in conventional wastewater treatment facilities, and thereby becomes a chemical that is added to soil during land application. As she shows, this compound strongly adheres to the soil and is not transmitted to groundwater or to plants. Read Dr. Brown's take on this in her June Blurb.

MAY 2013 RESEARCH SUMMARY

Dr. Brown revisits the controversy of a decade ago of the occurrence of flame retardants in biosolids. The scientific community has since discovered that these compounds are present throughout the ecosystem. When applied to land via the small loading in biosolids, these compounds go nowhere. Read Dr. Brown's synopsis in her May Blurb.

APRIL 2013 RESEARCH SUMMARY

This month, as our lawns begin to cry for a first mowing, Dr. Brown describes in her biosolids blurb for April the benefits of biosolids products for turf grass as reported in the peer-reviewed research.

MARCH 2013 RESEARCH SUMMARY

Dr. Brown discusses, in her biosolids "blurb," the unique qualities of the phosphorus that is in biosolids, and how research helps to clarify its potential for release to crops and, now importantly, to the environment.

FEBRUARY 2013 RESEARCH SUMMARY

Dr. Brown makes the case for biosolids products playing a big role in the exploding urban agriculture scene. See her blog here.

Nanoparticles and Biosolids

In this essay, Greg Kester, Biosolids Program Manager of the California Association of Sanitation Agencies, responds to recent publication in science journals of articles dealing with potential environmental pathways of exposure to metal nanoparticles. The bottom line is that nanoparticles react within the treatment process to produced non-available forms of metals. Two of the research reports do not treat the nanoparticles before applying them to soil, and thereby draw wrong conclusions about environmental risks.

Effect of Ferric Chloride Addition and Polymer Dose on Odors from Anaerobically Digested Biosolids

Matthew J. Higgins, Bucknell University Sudhir N. Murthy, DCWASA Douglas P. Yarosz, Bucknell University Srikanth Yamani, Bucknell University Dietmar Glindemann, Virginia Tech

Factors affecting odor production in Philadelphia Water Department Biosolids

Matthew J. Higgins, Bucknell University, Lewisburg, PA 17837 Sudhir N. Murthy, CH2M Hill William E. Toffey, Philadelphia Water Department Bradley Striebig, Penn State University Seth Hepner, Penn State University Douglas Yarosz, Bucknell University Srikanth Yamani, Bucknell University

IMPACT OF HIGH SHEAR SOLIDS PROCESSING ON PRODUCTION OF VOLATILE SULFUR COMPOUNDS FROM ANAEROBICALLY DIGESTED BIOSOLIDS

Sudhir Murthy, Ph.D., P.E., District of Columbia Water and Sewer Authority,5000 Overlook Avenue, SW Washington, DC 20032 Bob Forbes, Peter Burrowes, Tommy Esqueda, CH2M HILL Dietmar Glindemann, John Novak, Virginia Tech Matthew Higgins, Bucknell University Trille Mendenhall, Charlotte-Mecklenburg Utilities William Toffey, Philadelphia Water Department

Effect of Chemical addition on Production of Volatile Sulfur Compounds and Odor from Anaerobically Digested Biosolids Matthew J. Higgins, Bucknell University, Lewisburg, PA Sudhir N. Murthy, DC Water and Sewer Authority Douglas P. Yarosz, Bucknell University John T. Novak and Dietmar Glindemen, Virginia Tech William E. Toffey, Philadelphia Water Department Mohammad Abu-Orf, US Filter

MECHANISMS OF VOLATILE SULFUR COMPOUND AND ODOR PRODUCTION IN DIGESTED BIOSOLIDS

Matthew J. Higgins Dept. of Civil and Env. Eng. Bucknell University, Lewisburg, PA 17837 mhiggins@bucknell.edu Douglas P. Yarosz, Brown and Caldwell Yen-Chih Chen, Bucknell University Sudhir N. Murthy, DC WASA N.A. Mass, Bucknell University J.R. Cooney, Bucknell University

INFLUENCE OF SOLIDS CHARACTERISTICS AND DEWATERING PROCESS ON VSC PRODUCTION FROM ANAEROBICALLY DIGESTED BIOSOLIDS

Sudhir Murthy Ph.D., P.E., District of Columbia Water and Sewer Authority, 5000 Overlook Avenue, SW Washington, DC 20032 Matthew Higgins, Ph.D. and Yen-Chih Chen, Ph.D., Bucknell University William Toffey and Jim Golembeski, Philadelphia Water Department

HIGH-SOLIDS CENTRIFUGE IS A BOON AND A CURSE FOR MANAGING ANAEROBICALLY DIGESTED BIOSOLIDS

Sudhir Murthy, Matthew Higgins†, Yen-Chih Chen†, Christopher Peot and William Toffey‡ *DC Water and Sewer Authority, Washington, DC 20032, USA †Bucknell University, Lewisburg, PA 17837, USA ‡Philadelphia Water Department, Philadelphia, PA 19153, USA

PHILADELPHIA’S EXPERIENCE USING STATIC, NON-AERATED CURING TO PRODUCE LOW ODOR BIOSOLIDS

Ralph Eschborn, Mixing & Mass Transfer Technologies, LLC Matthew J. Higgins, Dept. of Civil and Env. Eng. Bucknell University, Lewisburg, PA 17837 mhiggins@bucknell.edu Trudy Johnston, Material Matters, Inc. William Toffey, Philadelphia Water Department Yen-Chih Chen, Bucknell University

Y. Chen, M.J. Higgins, S.M. Beightol, G.G. Araujo, S.N. Murthy, E.J. Barben, and W.E. Toffey_Department of Civil & Environmental Engineering, Bucknell University, Lewisburg, PA, U.S.A. (E-mail: cheny@bucknell.edu; mhiggins@bucknell.edu; smb038@bucknell.edu; garaujo@bucknell.edu; ebarben@bucknell.edu) DC Water and Sewer Authority, Washington, DC, U.S.A. (E-mail: SudhirMurthy@dcwasa.com)_Philadelphia Water Department