Presentations from the W3170 Meeting in Chicago

I found my trip to Chicago for the two-day W3170 meeting at the end of June not just full of challenging biosolids science, but one of surprises.
Many of you may not recognize the W3170. This is the group of more than 40 soil scientists at land grant universities who coordinate interstate research efforts as the W3170: Beneficial Reuse of Residuals and Reclaimed Water: Impact on Soil Ecosystem and Human Health (formerly W2170). In the late 1980s it was the W170 that provided the critical review of Part 503 regulations which resulted in extensive revisions that proved workable and are still in effect today. This review role is one that EPA acknowledges even today (Partnering to Ensure Effective Biosolids Management).

I was surprised to learn that W3170 has been meeting each year. This year’s meeting, held over three days, was organized as 15-minute presentations by the W3170 scientists on current research topics.  The setting encourages debate and inquiry, and it accommodates the testing of new ideas and methods in a friendly setting.  

This year was a bit different in that the W3170 is tasked with a re-write of a five-year research agenda which it will send to the USDA later this year.  The W3170 group had invited me, along with the managers of other regional biosolids associations, to be stakeholders in this re-write and submittal. I was asked, as part of the meeting agenda, to describe MABA’s mission, its current research program and the needs of its members for future research. The other regional biosolids associations did the same. And that was my big surprise: the take-home message from the W3170 is that we biosolids practitioners must not shirk our duty to support with time and money the mission of biosolids research and scholarship.

Sally Brown was the most direct with me at the meeting on this point. She chided MABA for having no research budget. Scientists in the W170 group thirty years ago had performed the research upon which Part 503 was based. While today’s scientists do their best to follow current issues, they hardly have adequate support today from public and regulatory agencies. The consequence is weak science for regulators (viz. PFAS) and a diminished pipeline of graduate students lining up to replace the longer standing panel of W3170 researchers.

The challenge: how can we step up? I have no clear answer to that rhetorical question. But I do want to introduce you to some of the key researchers who attended W3170 this year, describing their presentations and recent publications.  Maybe you will see why we all have a stake in the W3170 mission, and why we need to see that they are adequately funded in the future.

First, you may need to be reminded that this group sponsored a conference back in 2004, the proceedings of which were the basis for one of the best review articles ever put out for our industry. That is Sustainable Land Application “… an introduction to a subset of papers and posters presented at the conference, ‘Sustainable Land Application,’ … The overriding conference objectives were to highlight significant developments in land treatment theory and practice, and to identify future research needs to address critical gaps in the knowledge base that must be addressed to ensure sustainable land application of residuals.”

The lead author on that 2004 sustainability review article was George O’Connor [University of Florida, Soil and Water Science,,  352-392-1803]. Dr. O’Connor is one of the investigators for the WRF project Developing Exposure and Toxicity Data for Priority Trace Organics in Biosolids (TOBI2R15), which has the goal “to help develop a better understanding of fate and exposure of biosolids-borne constituents and their potential effects on terrestrial ecological health, and groundwater quality for the purpose of guiding decision makers, water agencies, regulators, product manufacturers, and consumers.” For the W3170 meeting, Dr. O’Connor discussed an aspect of this work, describing “Risks of Biosolids-Borne AZ [ azithromycin] and CIP [ ciprofloxacin].” He showed, through lab studies and risk assessment methodologies, the risks to be exceedingly low. Dr. O’Connor has had a history with this kind of research; in 2010 he was a principal in a WERF report TRACE ORGANIC CHEMICALS IN BIOSOLIDS-AMENDED SOILS. From this investigation came a journal article Risk assessment of land-applied biosolids-borne triclocarban (TCC), having the conclusion “The majority of biosolids-borne TCC exposure pathways resulted in no screening-level HQ [hazard quotient] values indicative of significant risks to exposed organisms (including humans), even under worst-case land application scenarios.” 

Another author on the 2004 sustainability review was Nick Basta [Nicholas T. Basta, Ohio State University, School of Natural Resources,, 614-292-2265].  Dr. Basta has been a major investigator on the behavior of lead in soils and its mitigation through a variety of practicable treatments.  In his recent journal article, Using Public Health Data for Soil Pb Hazard Management in Ohio, Dr. Basta reported ”Multiple Pb hazards were identified, including bare soil (74% frequency), deteriorated exterior Pb paint (74%), deteriorated interior Pb paint (72%), and settled Pb dust (72%). Bare soil collected from identified dripline areas contained 2638 ppm Pb above soils collected from bare soil play areas (P = .02).” For the W3170, he described his role in working with California regulators to recognize bioavailability as a necessary characteristic of environmental rulemaking (“Progress on bioavailability regulatory acceptance last year (ITRC, California)”).

Chip Elliott was a third author on “Sustainability” [Herschel Elliott, Pennsylvania State University, Agricultural and Biological Engineering,, 814-863-2062]. For W3170, Chip reported on the work he has been doing on the High Quality Biosolids from Wastewater, on which I and other MABA members have worked, particularly DC Water.  Dr. Elliott’s summary, “Biosolids Odors: Processing Effects and Predictive Modeling,” described a model that looked at such input parameters as dewatering method, oxygen uptake (measured by OxiTop), methionine ( a sulfur-containing protein) and iron content to predict odor qualities. But much of Chip’s work has been with water treatment residuals, phosphorus and environmental risks, with a very notable contribution to our industry in testifying at legislative and community meetings. Evidence of his willingness to be in front of issues is a recently published journal article, Relationship between total dissolved solids and electrical conductivity in Marcellus hydraulic fracturing fluids, where he determined that, contrary to current regulatory approaches, a “ single linear relationship is unreliable as a predictor of brine strength and, in turn, potential water quality and soil impacts from accidental releases or the suitability of HFFs for industrial wastewater treatment.”

Behind all compelling research over the past 40 years on the environmental effects of biosolids has been Rufus Chaney []. He attended W3170, even though he has been retired more than a year from the USDA.  This makes perfect sense if you consider the number of journal articles that have borne his name in the first half of 2018 alone, an astonishing SIX! For the W3170, he described a recent project with cadmium: “Using biosolids compost to limit Cd accumulation by spinach and lettuce grown on Salinas Valley Cd-mineralized soil.” But, when given the chance, Dr. Chaney eagerly described his current hot button work as an international soil consultant on phyto-mining for nickel with hyperaccumulating plants; this connects to his 2018 article Agronomy of ‘Metal Crops’ Used in Agromining. And, given my recent interest in the use of spent gypsum as a barrier to movement of phosphorus from farm fields, I was particularly interested in another of Dr. Chaney’s 2018 articles titled Impact of Flue Gas Desulfurization Gypsum and Manure Application on Transfer of Potentially Toxic Elements to Plants, Soil, and Runoff.   This showed that “the application of FGD gypsum significantly reduced P, As, and Fe concentrations in runoff, indicating that FGD gypsum can reduce the negative impact of manure surface application on surface water degradation.” Geez, we need this guy to keep working!!!

Our “Biosolids Blurb” superstar researcher attended W3170, but Chicago was just one stop on a professional trip to Bangladesh. This researcher is, of course, Sally Brown [University of Washington,, 206-616-1299]. Dr. Brown, who has always been the bridge between the theoretical and the practicable, spoke on “Making a topsoil product from San Francisco biosolids.” This foreshadows SFPUC’s steps toward advanced digestion and a DC Water-like commitment to urban soil blends. Dr. Brown seems to be almost single-handedly populating key Green Infrastructure job openings on the West Coast with her enthusiastic, visionary and well-trained students. A further example of her recent focus is the journal article Predictors of Phosphorus Leaching from Bioretention Soil Media. The issue of P loss from soil blends is important to future market-building for biosolids-based soils. In this paper, Dr. Brown reports: “The PSR was found to be a good predictor of P leaching from all BSMs with an R2 of 0.73 for total mass of P leached across all leaching events. The PSI was a poor predictor (R2< 0.3). The PSR also predicted total P in leachate for individual events more effectively than the PSI. Total P in the BSMs had no relationship to P in the leachate.”

One principal theme of W3170’s two-day program was revisiting the “time-bomb” hypothesis of biosolids risks. This hypothesis argues that, in the years following biosolids application, the oxidation of biosolids-sourced organic matter causes a release of contaminant metals for plant uptake or for leaching. This year’s Master of Ceremonies for W3170, Jim Ippolito [James Ippolito, Colorado State University, Soil and Crop Sciences,, 970-491-6501] spoke on this theme. He presented the case “Evaluation of time-bomb effect: metals availability after the cessation of long-term biosolids land application in Colorado.” To that Western U.S. case was added the presentation by Greg Evanylo [Virginia Polytechnic Institute and State University (VA Tech), Crop and Soil Environmental Sciences,, 540-231-9739] on “Evaluation of time-bomb effect: metals availability after the cessation of long-term biosolids application in Virginia.”

The “time-bomb” hypothesis was also addressed by this year’s W3170  host, the Metropolitan Water Reclamation District of Greater Chicago (MWRD). Chicago is the model every large public agency ought to follow, having a strong research group employing soil scientists [Environmental Monitoring and Research Division, Monitoring and Research Department, Metropolitan Water Reclamation District of Greater Chicago, 6001 W. Pershing Road, Cicero, IL 60804, USA]. Dr. Albert Cox reported “Accumulation of metals in edible tissue of garden vegetables after the cessation of Nu Earth biosolids application,” and Guanglong Tian presented “Crop uptake coefficient of metals at 10, 20, 30 years after the cessation of long-term biosolids application in Illinois.”

Altogether, four presentations on the “time-bomb” were made, and, NOPE, zero scientific evidence to support the “time-bomb” hypothesis was reported.

With that said, today’s research focus is not on this old, tired, time-bomb hypothesis. Rather, Dr. Ippolito is working with soil health. Dr. Evanylo is working on soil blends and nitrogen mineralization. Dr. Cox is working with land restoration, and his Chicago colleagues are doing carbon sequestration from biosolids and algae biomass production. All these topics address current issues and have immediate importance to biosolids.

Of great interest to the entire group was information on the fate of organic pollutants, because biosolids may be a “vector” for their movement from house drain to farm soil.  As mentioned above, Dr. O’Connor reported on the fate of two recalcitrant antibiotics, azithromycin and ciprofloxacin. Hui Li [, Michigan State University] discussed “Plant uptake of pharmaceuticals from soil.” Drawing upon his recent publication Uptake and Accumulation of Pharmaceuticals in Overhead- and Surface-Irrigated Greenhouse Lettuce, Dr. Li explained that neutral-charged, small molecules are taken up by roots and translocated into plant tops; large, charged molecules are not. His published research includes studies of carbamazepine and tetracycline, both which can persist in soil and get into plants.

But the real bugaboo in biosolids today is not pharmaceutical residues, but the “pollutant of the day” PFAS, or Polyfluoroalkyl Substances. PFAS is an umbrella term that takes in an array of old Teflon and Scotchgard formulations that resist degradation during wastewater treatment, that are water soluble and leachable and that may be a health concern at low concentrations in drinking water. Biosolids contain PFAS, inevitably. Relentlessly energetic Purdue PhD student Rooney Kim Lazcano had ground breaking results to share on “Per- and Polyfluoroalkyl Acids (PFAAs) in Commercial Biosolids-based and Non Biosolids Fertilizers.” NEBRA’s representative, soil scientist Andrew Carpenter [Northern Tilth, P.O. Box 361, Belfast, ME,, 207-338-5500] described the results of NEBRA’s recently completed, voluntary survey of PFAS from New England wastewater and paper mill residuals. These two presentations set the stage for an awkward conversation about the inadequacy of current analytical procedures and of EPA guidance for analysis of these compounds. In some states, the issue of PFAS has the very real potential to stop land application of biosolids, despite this inadequacy. That is serious business, and we need capable scientists to step up and be heard.  

Are you now convinced? Do we not have an amazing group of scientific centers-of-excellence ready to address an array of biosolids issues? Do you need reminding of the issues needing scientific attention? We are facing evidence of nitrogen and phosphorus releases, risks from persistent pollutants, the ongoing need to mitigate odor nuisances, the concern for antibiotic resistance gene migration, and the opportunity to restore soil health, to name a few big ones.  Our industry’s integrity and reputation are at risk if we fail to support the level of scholarship that can apply current tools, knowledge and scientific skills to these topics and to questions reasonably posed by our customers and regulators. I say, the time has come for us to re-invest in science. If you do, prepare yourself for the many Surprises of Biosolids Science.