MidAtlantic Biosolids Association

Biosolids Research Updates: Blurbs by Dr. Sally Brown

Get the Lead Out

Lead contaminated soils in inner cities is a widespread problem with historical roots.  Back in the day lead (Pb) was added to paints to make them dry faster and last longer and to gasoline to stop engine knocks.  That all stopped by the time I was in middle school (aka a very long time ago).  But that lead doesn’t go anywhere.  If you sample soils in a city, particularly in the older parts of that city, there is a good chance that the total soil Pb will measure well over background, likely in the 100s of ppms. 

The big concern with Pb in soils is for little kids.  The kids are at risk first because they find dirt a lot more appetizing than grownups and second because their bodies are so much more efficient at absorbing the metal.  Lead exposure can cause a range of problems including impaired brain function and development.  We typically measure Pb concentration in blood and as our understanding of the impact of elevated blood Pb has expanded, the regulatory limits for acceptable blood Pb have decreased.  At mining sites, where there is a legacy of soil Pb contamination from mining and smelting, the EPA Superfund program has had a dig and haul policy- dig out the contaminated soil and put it in a repository.  Replace it with clean stuff (see Pb graffiti below.  That approach doesn’t work so well for Brooklyn, Oakland, St. Louis…. 

First- where would you put all that soil from Brooklyn (remember that trees do grow there- https://en.wikipedia.org/wiki/A_Tree_Grows_in_Brooklyn_(novel))?  Then what would you put in its place?  This month’s library is all about soil Pb in urban areas and how composts and biosolids are the solution to this problem.  The first article is a new one from Howard Mielke and others.  Dr. Mielke is a professor at Tulane and he believes that the appropriate/ safe concentration of Pb in soils is about zero.  He is well respected but very cautious.  For some perspective, the normal long standing EPA regulatory value for soil Pb is 300 ppm for areas where children are likely to be exposed.  This paper follows the Pb concentration in soils in New Orleans and notes that as they have gone done, children’s blood Pb levels have also decreased.  Much of the decrease is attributed to Hurricane Katrina which deposited new materials on surface soils, effectively reducing the Pb concentrations.  This article shows a link between the areas where flooding occurred, effectively reducing the soil Pb concentration and decreases in children’s blood Pb levels. 

The next article, also co- authored by Dr. Mielke takes us to Brooklyn.  Here the focus is eggplants, rather than trees.  The authors are looking for some clean dirt to use in community gardens.  There is limited composting done in NY and despite Pam Elardo moving from the King County WWTD to lead the NYC wastewater program, most of the biosolids are landfilled.  They found some sediment and had some food/yard compost donated from a local group.  All manufactured soils had low Pb and the plants grown in these gardens were also very low in Pb.  I would be more than happy to send you a paper that I co-authored with Ganga Hettairachchi and Rufus Chaney about the use of composts to reduce concerns about Pb in urban agriculture- but it has been in the library before and here I wanted to show that Mielke who is so worried about urban soil Pb sees compost and clean soils as a solution. 

From here we go to the way back time machine and paper #3.  This starts the tale of why composts and biosolids are not just good for urban soils because they are typically low in Pb, but because they actually make the Pb in the soils less dangerous.  This paper reports on finding from a WEF study.  I did this work while working with Rufus Chaney at USDA.  We took different types of biosolids and added them to a high Pb soil from Baltimore.  We tested changes in Pb availability by feeding the soil to mice and by using different soil extracts.  What we found was pretty impressive.  The biosolids compost produced using high iron biosolids (DC Water) reduced not only total Pb concentrations but also the portion of the Pb that was dangerous.  We saw about a 30% reduction in Pb bioavailability.  Important to note here that the high lime biosolids actually increased the Pb availability.  This was the beginning of a larger body of work showing that biosolids can reduce the hazards associated with Pb by changing the mineral form of the metal.  The high lime biosolids made more of the lead convert to lead carbonate (cerrusite) which is easily dissolved in an acid stomach.  The high Fe biosolids caused the Pb to partition to iron oxides and to organic matter.  I can send you more papers on this stuff- just let me know.  But the point of this work comes out in the 4th paper. 

For the 4th paper we go back to Dr. Mielke.  I had known him through Rufus and when he was in Seattle he looked me up.  We had lunch with his daughter, a medical Dr. at UW and I took him down to Tagro.  He had a tour of the facility and we went to see some of the community gardens that had the Tagro delivered.  He thought that this biosolids stuff was a great idea for the Pb problem.  We ended up bringing several bags of the potting soil back to his daughters’ house in Magnolia.  It made enough of an impression on him that he asked me to contribute to a review article on biosolids as a solution for urban Pb contaminated soils.  That review article is #4 in the library.  Very nice to see that biosolids are considered as a solution by one of the most cautious and highly respected scientists in the field.

Finally we get to paper #5.  So they work well in the lab but do they stand the test of time?  People might wonder about the efficacy of biosolids in binding soil Pb.  As part of the work that started with the 2003 paper, we ended up testing that high Fe biosolids compost at a smelter contaminated site in Joplin, MO.  We set up field plots testing a range of different types of phosphorus, compost, and iron rich materials, alone and in combination.  We had the compost shipped out from DC Water.  Here it is below right on top of the plots

Below is a shot of the field site itself

That was back in about 1997.  Turns out that scientists went back and collected more soil from the field site recently.  More mice were fed and the Pb speciation was determined using X-Ray adsorption spectroscopy.  The compost (with added P, they didn’t test the compost alone treatments) worked better than ever.  In fact the compost (as well as the high Fe material + P) were more effective than the phosphorus treatments at reducing the Pb availability.  Phosphorus has long been seen as a gold standard here as it can precipitate with the Pb to form pyromorphite- a highly insoluble Pb mineral.  The reduced adsorption of Pb by the mice was accompanied by changes in the mineral form of the metal, as measured in the fed soil as well as the mice feces. 

Take home of the library- soil Pb in urban areas is a problem.  Biosolids and composts- as long as they are low in Pb and not high in lime, are the solution. 

I love being the solution. 

To view the journal article citations, click here.

Sally Brown, University of Washington


Biosolids NewsClips: Connecting Biosolids to the World

News from Within the MABA Region

Somerset County Wastewater Treatment Plant Accepts Potentially Contaminated Runoff
Somerset County, NJ (11/9/19) - “A wastewater treatment plant in Somerset County, N.J. accepted more than 250,000 gal of runoff from a New Hampshire landfill potentially contaminated with per- and polyfluoroalkyl substances (PFAS).”

News from Beyond the MABA Region

EPA to Offer $4.8 Million in Grants to Study Impact of PFAS
National (11/22/19) - The EPA has offered $4.8 million in grants to study the impact of PFAS. It hopes to measure “PFAS occurrence, fate, and transport in water sources used by rural communities and agricultural operations.” The EPA also seeks data on PFAS treatments that will help remove PFAS from “small drinking water and wastewater systems,” as well as biosolids produced by wastewater plants and sold to farmers as fertilizer.

Burlington, N.C. Wastewater Treatment Plants Being Sued for PFAS Pollution
Burlington, NC (11/8/19) - “The Southern Environmental Law Center issued a notice with the intent to sue Burlington, N.C. for per- and polyfluoroalkyl substances (PFAS) pollution in Haw River and Jordan Lake.”
Haw River Assembly to Sue Burlington Over Chemicals in Sewage
SELC Plans to Sue Burlington Over PFAS, 1,4-Dioxane Pollution in Drinking Water, Sludge

Debate Over Science and Risks Shapes 3M's Lawsuit Against N.H.'s PFAS Water Standards
New Hampshire (11/4/19) - Former state Rep. Mindi Messmer, sponsored the bill that led the New Hampshire Department of Environmental Services this year to set the strictest PFAS limits of their kind in the country. 3M, the chemical company that helped invent PFAS, initiated a lawsuit against the new regulations. A cattle farmer, a fertilizer company and a town water utility all joined 3M opposing the regulations. 
Wastewater Monitoring Continues

 Clinton, Miss., Wastewater Facility Named 'Plant of the Year' by MWEA
Clinton, MI (11/7/19) - The Southside Wastewater Treatment Plant in Clinton, Mississippi was named Plant of the Year by MWEA. The plant is one of two plants in MI, that converts sludge into biosolids.

West Lafayette and Lafayette Leaders Looking into Combining Centers for Bio-Solid Waste
Lafayette, IN (11/12/19) - Lafayette and West Lafayette leaders are looking into combining centers for biosolids. Indiana Finance Authority awarded the city of West Lafayette a $30,000 grant. Part of those funds will go toward conducting a study examining how much biosolids they're collecting.

Turning (More) Fat and Sewage into Natural Gas
North Carolina State (11/13/2019) - North Carolina State University researchers have been exploring what the best balance of biosolids and GIW for maximizing methane production is in a wastewater treatment plant. 
Sewage Sludge, Grease Combine to Create More Methane

In King County, Washington, Human Waste is a Climate Solution
King County, WA (11/19/19) - Climate Connections published this article shining light on the benefits of land applying biosolids. The article shines light on King County’s Loop program as a program that has developed various partnerships in order to help conserve various natural resources. 

Fort Worth Considers Drying Human Waste to Make Better Fertilizer
Fort Worth TX (11/19/19) - The city of Fort Worth is looking to install a dryer at its facility to reduce the weight of the biosolids it trucks out of the plant. This is part of a larger plan to have a contractor sell biosolids as a fertilizer. 

Neighbors Question Odors, Unassessed Pollutants in Biosolids Spread Across Ohio Fields
Cardington, OH (11/21/19) - Neighbors to farms land applying biosolids near Cardington, Ohio have complained about the odor of the material and expressed concerns about the pollutants it may contain.

News from Abroad

2019 European Biosolids and Organic Resources Conference – Programme Unveiled
Greater Manchester, England (11/4/19) - Aqua Enviro has announced the program for the 2019 European Biosolids and Organic Resources Conference. For full event details and to register your place visit www.european-biosolids.com.

Recycling Sewage Sludge Ash While Recovering Phosphorus and Producing Sustainable Concrete
Technical University of Denmark (11/19/19) - Countries in Europe are starting to create legislation requiring mono-incineration of sewage sludge and recovery of phosphorus from the sludge ash. “EasyMining is currently building full-scale plants (in Sweden and Germany) to recover phosphorus from sewage sludge ash through their Ash2Phos technology.”

Turtle Valley Stops Roadblock for Winter, Awaits News on Kamloops' Biosolids Plan
Kamloops, BC, Canada (11/7/19) - The city of Kamloops has been trying to work through challenges of land applying their biosolids at two different sites. Protesters have prevented the trucks hauling biosolids from accessing land in Turtle Valley and delays in permitting have slowed application to the other site. One thing many groups are waiting on is the review of the Organic Matter Recycling Regulation (OMRR) of B.C. “The regulation has been undergoing a comprehensive review since 2018 to ensure it remains protective of human health and the environment.”


Biosolids TOPICs: Interesting Ideas Connected to the World

Say YES! to Biosolids Carbon Storage

Mark sat across from me finishing off his lunchtime appetizer of pea soup and main dish of goulash and spaetzle with a dessert of chocolate pecan pie. “I just twitch my elbow and I will burn off this pie, so fast is my metabolism. That’s the thing with me, the more fuel I put in the tank, the faster I burn.” His girlfriend, Laura, visibly annoyed, replied: “Let me have just one bite, but it is going straight to my hips, and I don’t need that.” I mused over the inexplicably different pathways of food in the human body; how can pathways of carbon energy be so different, with one “good” (like Mark’s muscle burn) and one “bad” (like Laura’s belly fat storage)?

I would like to flip this judgment: storage is good and burning is bad. When given the chance, I like to explain that biosolids is well-balanced nutrition for the soil, full of carbon energy and nutrients, containing every trace element necessary for plant and soil microbe health.   As biosolids managers, we get to choose the end goals and the pathways to get there. Do we want to blow the biosolids carbon through processes that extract energy and release it as atmospheric carbon? Or, do we instead direct biosolids carbon to storage in the soil?

You would think all soil scientists would jump at the soil storage option. Nevertheless, keeping biosolids carbon away from the soil seemed the message from a recent “biosolids webinar” sponsored by the Pennsylvania Farmers Union. The guest scientist was Cornell’s Murray McBride, who poured through his litany of concerns (see Case for Caution Revisited), including familiar elements like molybdenum and less familiar ones like thallium, including familiar fears of persistent pollutants, and including familiar concerns like excess nutrients.  The bottom-line message from McBride was that we should apply the precautionary principle to soil management, in which case farmers would avoid biosolids.

I, of course, hold the entirely opposite view.  That is, wise soil management demands use of biosolids. I am compelled by the message of a large group of scientists that the urgent need is to restore soil carbon. I hold that biosolids recycling to soil is a valuable climate change mitigation measure.

You may have noted the cosmic irony that the report of  World Scientists’ Warning of a Climate Emergency came literally one day after the media attention to the U.S. submittal of paperwork to withdraw from the Paris climate accord (On the U.S. Withdrawal from the Paris Agreement). The statement, ratified by 11,000 scientists, says “We should leave remaining stocks of fossil fuels in the ground,” while Secretary Pompeo’s press release says the U.S. approach “uses all energy sources and technologies cleanly and efficiently, including fossils fuels.”  Importantly, the scientists assert that “an immense increase of scale in endeavors to conserve our biosphere is needed to avoid untold suffering due to the climate crisis.” Efforts, they say, should include “natural climate solutions [NCS].”  A recent article on  Natural climate solutions says “NCS offer a powerful set of options for nations to deliver on the Paris Climate Agreement while improving soil productivity, cleaning our air and water, and maintaining biodiversity.”

NCS is an opportunity for the wastewater industry.  As environmental professionals, we can choose to use biosolids projects that lock ourselves into infrastructure and programs that sequester biosolids carbon in soil and support NCS.

Do we know that the carbon in biosolids can be sequestered? The science of soil organic matter is complicated, and the fate of biosolids-borne carbon is especially so. The study Soil Carbon Sequestration Resulting from Biosolids Application  offers this challenge: “there is still limited knowledge on soil sequestration mechanisms of biosolids-borne C or the main factors influencing this capacity.”

Nevertheless, a clear and affirmative answer is emerging.  A scan of Google Scholar reveals an impressive record of evidence that biosolids benefits soil carbon. The journal article Relationship Between Mineral Soil Surface Area and Carbon Sequestration Rate for Biosolids Added to Soil concluded “[t]herefore, land application of biosolids is an effective way to enhance carbon sequestration in soils and reduce greenhouse gas (GHG) emissions.” 

Biosolids has been shown to sequester carbon in a variety of cropping systems.  Biosolids works for dry wheat land soils. In Soil carbon and nitrogen fraction accumulation with long-term biosolids applications researchers concluded “Biosolids markedly elevated total, stable and LF [light fraction] soil C and N pools in semiarid conditions, while maintaining comparable wheat productivity to commercially fertilized wheat-fallow.”  It works for Midwest corn.  The report Soil carbon sequestration resulting from long-term application of biosolids for land reclamation” found “[o]ur results indicate that biosolids applications can turn Midwest Corn Belt soils from current C-neutral to C-sink.”  Biosolids also worked well for the cultivation of a willow bioenergy crops. The report Life cycle assessment of a willow bioenergy cropping system  reported that the “[r]esults from the LCA support the assertion that willow biomass crops are sustainable from an energy balance perspective and contribute additional environmental benefits.”

Biosolids of different forms all generally yield increases in soil carbon stores.  This was the specific focus of the report The effects of fertilization with anaerobic, composted and pelletized sewage sludge on soil, tree growth, pasture production and biodiversity in a silvopastoral system under ash (Fraxinus excelsior L.).  It found “[a]naerobic sludge had a higher initial effect on both tree and pasture productivity. Pelletized sludge sustained better tree and pasture production. Composted sludge was found to be the most appropriate treatment for improving soil characteristics over the long term on sandy soils. It was concluded that pelletized sludge should be promoted because it enhances productivity, allows for better nutrient recovery and is less costly to store and apply compared with anaerobic sludge and composted sludge.”

Is the carbon added to soil by biosolids is transitory? Nutrient-rich biosolids might stimulate microbial decomposition of organic matter, thereby blowing off the carbon might, instead of storing it.  This was addressed by Soil Carbon Characterization 10 to 15 Years After Organic Residual Application.  This study showed that: “The addition of organic residuals… thus improves long-term soil C stability.”

Biosolids contribution to soil carbon storage is recognized by international experts.  The United Nations Climate Change Convention has formally granted carbon credits for such mitigation measures. The biochemistry was worked out for biosolids in the report Degradation rate model [DRM} formulation to estimate soil carbon sequestration from repeated biosolids application: “Based on the 34-yr database, the DRM simulates the process that decomposes SOC [soil organic carbon] produced by biosolids application into C in biosolids that have not been degraded….  and provides an easy quantitative method for evaluating C credits from biosolids added to soil.”

Another question answered affirmatively was that when biosolids is used for carbon sequestration no negative effects are seen in soil health. A study in the U.K., Long-term Effects of Biosolids on Soil Quality and Fertility, concluded “no adverse effects on crop quality were observed.”  Soil fauna seems to benefit from biosolids nutrition. In Effect of biosolid amendment on enzyme activities in earthworm (Lumbricus terrestris) casts scientists determined “Enzyme activity… and the contents of organic matter and nutrients N and P in earthworm casts and surrounding soil increased with increasing biosolid application.”

Repeated applications of biosolids are also effective for carbon storage and compatible with soil health. The report Long-Term Effects of Land Application of Class B Biosolids on the Soil Microbial Populations, Pathogens, and Activity concluded “[o]verall, the 20 annual land applications showed no long-term adverse effects, and therefore, this study documents that land application of biosolids at this particular site was sustainable throughout the 20-yr period, with respect to soil microbial properties.”

We have a big “thumbs up” for use of biosolids for carbon storage in soil.  Chocolate pecan pie may have its detractors in the healthy-eating arena, but undoubtedly it offers carbon for storage in the human body. Biosolids may have its detractors in the organic farming arena, but undoubtedly it offers carbon for storage in the soil. There is only one sensible step to take when faced with the option: Say Yes to Storage!



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2019 Summer Symposium

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