MidAtlantic Biosolids Association

SPOTLIGHT on Biosolids YP (Young Professionals)

This SPOTLIGHT is a special treat for us all as it celebrates the young talent in our environmental realm. What is more, we are able to call out several special opportunities.  1. Join the YP Committee, by notifying [email protected] to be added to the list and putting Tuesday, May 18th at 10 am. on your calendar for the next YP meeting.  2. Speak at our July Symposium, as the Programming Committee is reserving a slot during the July Virtual Biosolids Symposium for a YP presentation; so while the official deadline from proposals is passed, send yours by the end of this week to Howard Matteson, [email protected] 3. Be the MABA Social Media Guru, as the Communications Committee is in need of a social media savvy young person to help MABA better engage through its Facebook, LinkedIn, Twitter, Instagram, and YouTube pages; contact [email protected]  with your ideas. 

Carolyn Christy 

Carolyn Christy

Carolyn Christy, RDP Technologies, ([email protected], 610-574-3037). Carolyn has a degree in environmental earth sciences with a minor in soil science and a minor in agricultural business from Cal Poly San Luis Obispo. She has been working for RDP Technologies for over 5 years doing sales support and marketing. RDP is a family-owned manufacturing company that specializes in lime chemical feed equipment. Carolyn says, “I am passionate about creating a quality biosolids end product for regenerative agriculture. I have given a number of papers on this subject. I am also starting the YP subcommittee for MABA and am looking for more people to get involved.” If you are in the YP category, consider attending the next MABA YP Committee meeting! Carolyn enjoys being outside doing recreational sports. Her favorites are hiking, running, swimming, skiing, and road biking.  The picture shows Carolyn hiking Zion national park in the fall of 2019. 

DJ Wacker          

DJ WackerDJ Wacker, Project Engineer, RK&K (410-462-9192, [email protected]). DJ’s introduction into the world of biosolids started about 10 years ago as an intern at RK&K. He was tasked with collecting and lugging several 5-gallon samples of undigested sludge out of the lower level of a pumping station in the 95-degree summer heat. Somehow that did not deter him from biosolids, in fact, he went on to design that plant’s dewatering facility. DJ reports, “I ended up doing my master’s thesis on anaerobic digestion and never looked back.”  DJ loves seeing projects from conception all the way through commissioning and has had the opportunity to work on a wide range of biosolids projects from thickening and anaerobic digestion to thermal drying, digester gas utilization, and RNG. He also loves innovation in technology and helping clients find the right process that suits their needs and goals. DJ is now carrying his biosolids enthusiasm out into the wider world; check out his recent blog by clicking HERE. When not working in the world of biosolids or wastewater, DJ typically looks for his next destination to travel to and/or thrill-seeking adventure. You can see that in this picture of DJ running with the bulls in Spain.

  Emma Yates 

Emma YatesEmma Yates, Sales Rep, WeCare Denali – Hilburn, NY (845-521-6568, [email protected]). Emma has served as a Business Development Representative for WeCare Denali for the past four years. In this position, she is responsible to sell and market WeCare Compost®. Emma graduated from Allegheny College where she majored in Environmental Science. While she tried to avoid taking any classes related to soil, Emma ended up in a class where they were tasked to increase their school's carbon sequestration through composting. She became smitten with compost and found her home at WeCare Denali where she could create a large-scale impact in the industry and work on an incredible team of composting experts. Marketing biosolids and green waste compost in the tri-state area is a dynamic operation that has provided her with countless connections, learning opportunities, challenges, and enjoyment. Emma currently resides in Jersey City, NJ, and spends her free time practicing yoga, hiking, or exploring the area’s food scene. 

 Garrett Benisch     

Garrett BenischGarrett Benisch, Director of Design Development, Bioforcetech ([email protected], (973) 985-4265). From a young age, Garrett has been fascinated by materials. He says, “As my mother would work on custom centerpieces for parties in our backyard, I would be completely content ‘painting’ water on the railings of our wooden deck just to watch it change color, absorb the water, and then dry out again.”  Still today, Garrett walks through a park or cuts vegetables while cooking, intrigued by how materials change and transform as people interact with them.  He completed his Master's thesis in Industrial Design, Sum Waste, which envisioned turning biosolids into clean valuable resources that society could interact with directly. Shortly after graduating, he met Valentino Villa at the MABA Summer Symposium, and soon after joined the Bioforcetech team to research and develop what he now calls OurCarbon.™  The new job took him from Brooklyn to San Francisco in the midst of a world-changing pandemic, spending time on the phone with testing labs, manufacturers, and Instagram influencers alike.  When not tinkering with OurCarbon™ in the office, Garrett can be found at Ocean Beach with his dog, Hoya, or catching waves in the surf, with very little grace and a really big smile.


Kelli Timbrook

Kelli TimbrookKelli Timbrook, Facilities Manager, Casella Resource Solutions (518-631-3763, [email protected]). As a lifelong environmentalist, Kelli got her start in traditional recycling helping to build municipal and K-12 recycling programs. She then transferred those waste diversion skills into beneficial use of residual organics, always with the same goal of reuse, diverting as much material as possible from the landfill. In her seven years with Casella, she has contributed to the diversion of over 10,000 tons of organic materials, such as biosolids, paper mill residuals, and food scraps. In addition to her work with Casella, Kelli is a Board member of the New York State Association of Reduction, Reuse and Recycling (NYSAR3) since 2012, serving two terms as President from 2016-2020, and Vice Chairperson of the Federation of Solid Waste Association of NY.  When she is not hanging out at compost facilities or WWTPs, Kelli is busy dragging her two kids and husband around both local trails and the Adirondacks (she aspires to be a 46er, climbing all 46 peaks in the Adirondacks) while commenting on the soil and crop health of all the farm fields they pass along the way. 


Biosolids News You Can Use

ScienceTalk: Benefits to be reaped if we don't let wastewater go to waste
The Strait Times, Singapore (4/12/21) - Wastewater treatment processes also produce sludge that needs to be treated before it can be safely discharged to a landfill or incinerated (typically, the ash generated from the incineration will end up in a landfill too). A common sludge treatment method is anaerobic digestion (AD) - a biological process that not only treats the sludge by removing the undesirable organics in it but also reduces the volume of sludge that needs to be discarded or incinerated.

A link to the article can be found here.
Microplastics in Sewage Become 'Hubs' for Drug-Resistant Bacteria: Study
New Jersey Institute of Technology (3/27/21) - A new study shows microplastics can be a hub for drug-resistant bacteria. Researchers inoculated batches of sludge with polyethylene and polystyrene and observed what species tend to grow on the microplastics. “The researchers found that three genes in particular — sul1, sul2, and intI1— known to aid resistance to common antibiotics, sulfonamides, were found to be up to 30 times greater on the microplastic biofilms than in the lab's control tests using sand biofilms after just three days.”

MNS, IWK Plant 100 Trees to Revitalise Urban Forest
Malaysia, Kuala Lumpur (3/25/21) - The Malaysian Nature Society (MNS) used 500kg of biosolids as a soil amendment when planting 100 forest trees as part of the “Adopt a Tree” campaign in an urban forest known as Khazanah Rimba. The biosolids came from Indah Water Konsortium’s (IWK) sewage treatment plants, part of Malaysia’s national sewerage company. 

Biosolid Storage Facility Issue Back on Table, LPAT to Decide in May
Adelaide Metcalfe ON, Canada (3/24/21) - LaSalle Agri Fertilizer wants to construct a facility to store biosolids pellets in Adelaide Metcalfe, but the company and landowner of the proposed site are meeting resistance from the community. 

Ohio EPA Issues Permit for Emerald BioEnergy
Westfield Township, OH (3/30/21) - Ohio EPA has issued a permit renewal to Emerald BioEnergy to update requirements for biosolids storage and land application. Emerald BioEnergy is no longer accepting sewage sludge or biosolids and the renewed permit updates requirements for biosolids storage and land application for what remains. “When land applying treated digestate, the facility is required to adhere to the final permit until a land application management plan (LAMP) and permit to install (PTI) are approved. After all of the biosolids are removed from the storage ponds and a LAMP and PTI have been issued, the final permit may be terminated.”

New Tokyo Facility to Produce Hydrogen from Sewage Sludge
Tokyo, Japan (4/2/21) - The city of Tokyo has welcomed the end of construction work on a facility that will turn sewage sludge into hydrogen fuel for fuel-cell vehicles and power generation. Japan Blue Energy Co Ltd was the company that developed the technology the facility will use for converting waste into hydrogen. Located at the Sunamachi Water Reclamation Center near Tokyo Bay, the facility will produce 90 - 110 pounds of hydrogen per day, using 1 ton of dried sewage sludge. This output is enough to fuel 10 passenger vehicles or 25 fuel-cell e-bikes.


Dust to Dust

Dust is a big deal! Viruses have so commanded the front stage of our news media that you may have missed other big “dust” stories. China is having a BIG dust problem. The article “Apocalyptic skies as Beijing hit by worst sandstorm in a decade” (March 15, 2021) explains winds off Mongolia are carrying a dense cloud of dust to Beijing. This is not an issue with serious health and environmental implications (Characterization of the composition of dust fallout and identification of dust sources in arid and semiarid North China. The newspapers are happy to remind us that early Spring brings tree pollen, a phenomenon steeped in science  Pollen calendars and maps of allergenic pollen in North America.  Two weeks of dry weather in the mid-Atlantic, and wildfires are releasing unhealthy soot: “Wildland firefighter smoke exposure and risk of lung cancer and cardiovascular disease mortality.” While the dangers of dust-borne lead in homes is well established (Children’s Lead Exposure: A Multimedia Modeling Analysis to Guide Public Health Decision-Making), household dust contains many more compounds of concern, many of which we see also in our wastewater and biosolids, such as flame retardants and phthalates: Tracing the chemistry of household dust The sloughing skin that joins cloth fibers in the household dust. Worse yet, some of the dust may be radioactive (Health Implications of Fallout from Nuclear Weapons Testing through 1961). On a lighter note, we also learned in a January 2021 news article that amidst the load of anthropogenic dust, which has greatly accumulated in my house during the pandemic lockdown, is some very ancient dust (7 billion-year-old stardust is oldest material found on Earth), older than our solar system. Yes, dust is a big deal for scientists, inhabitants, and life in the world.

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

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

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

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

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

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

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

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

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

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

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

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


Research Update from Sally Brown, University of Washington

Biochar from Biosolids

Happy spring to all, hopefully, a shot in the arm both literally and figuratively. 

BioforceA year ago, the library was all about SARS-CoV-2 and covid 19.  This year we are back to a more mundane and annoying topic -- pyrolyzed biosolids or biosolids-based biochar.  I was asked to review an analysis of this treatment option recently and declined, but the request did show that the interest in this option is still out there.  I’ve also been told by a highly reliable source (Andrew Carpenter) that there is a biosolids pyrolysis plant in operation in California.  So however much I want this to go away, my wishes have not yet been granted.  Proponents of this stabilization technology argue that the finished material can be used as a soil amendment.  I checked to see if there was any literature on the topic.  There is, but not that much.  Here is what I found.

The first paper in the library (Biochar from Biosolids Pyrolysis: A Review) has Jorge Paz-Ferreiroas a first author.  He is from Australia and is faculty in the school of engineering.  He is a co-author of a number of papers on this topic.  This one is a general review.  You can skip much of the first part. It is a general review of the basics of biosolids with a focus on hazards.  The focus goes to pyrolysis, starting with section 2.3.  You can (in my opinion) see that he comes to this with a clear bias, stating early on that pyrolysis is a lower carbon footprint option.  Obviously, he hasn’t looked at our BEAM model.  However, the review provides a good summary of the process, factors that can impact the output, and characteristics of the final product.  Some key points: higher burn temperatures increase P and K content of the material (good), but decrease N (bad).  Higher temperatures also decrease salts (good) but increase heavy metals (bad).  There is also a table of growth studies.  Here a basic take-home message is that biosolids char does not work as well as biosolids for plant growth.  Reduced total and available N is generally to blame.  Phosphorus in biosolids chars seems to be plant available with total concentration not reduced by the cooking process.  There is also a discussion of the impact of pyrolysis on organic contaminants in biosolids with studies showing the removal of antimicrobials and some PAHs.  This discussion implies that this process might alter PFAS, but that implication is in my brain rather than in the paper.  The authors point out that some heavy metals of historical (mercury and arsenic) volatilize during the process, becoming the atmosphere’s problem.  While other metals concentrate, metals in the biochar matrix typically have low availability.   He talks about using this material as a component of compost mixtures to reduce N loss.  Also, he mentions a study that tested biosolids char as a replacement for a portion of the peat used in horticultural applications.  The world is the oyster here.
The second paper (Physicochemical Properties of Biochars Produced from Biosolids in Victoria, Australia) includes the same author, but instead of a review of the literature, the authors present original data.  They took biosolids from several plants near Melbourne, Australia, and analyzed them as is and post pyrolysis at 500°C and 700°C.   The paper has a few tables of data that show you what happens.  Here are the results in an easy-to-read form.

For the third paper, we will leave Jorge Paz-Ferreiro for some other authors.  Most authors of paper #3 (Pyrolysis methods impact biosolids-derived biochar composition, maize growth, and nutrition) come from Brazil, with some help from Nick Comerford from the University of Florida.  Nick is a former president of the Soils Society, so I am hoping this work is well done.  The authors here tested two types of methods to make char and examined the effect of the two materials on corn germination and growth. In both cases, biosolids were used as the feedstock.  The first batch was made in a kiln, representative of small-scale operations, and the second batch was made in a muffle furnace, as would be done on a treatment plant scale.  The authors then tested each product for seed germination and plant response.  Application rates for each material were 0, 5, 10, 20, and 60 Mg/ha.  All treatments got supplemental fertilizer.  You read that right. With biosolids biochar, the authors added extra fertilizer.  The bottom line on the growth trial here was that yields were all the same, with one exception.  The small-scale biosolids biochar added at the highest rate grew smaller corn than all of the other treatments.  The large-scale char did the same as the control across all application rates.  In other words, making char from biosolids takes away the biosolids magic that farmers have come to appreciate. 

The 4th paper (Direct and residual effect of biochar derived from biosolids on soil phosphorus pools: A four-year field assessment) marks the 3rd and final appearance of Paz-Ferreiro with a continuation of the Brazilian influence.  Here the authors focus on P availability in tropical soils amended with biosolids biochar.  Tropical soils have extremely high concentrations of iron that impart their red color.  The same way that adding Fe to wastewater treatment removes P from solution, having so much Fe makes the soil good at binding P.  Before the study even started, the authors added P and K to the whole field twice.  This is a very different scenario from fields on less weathered soils where excess P is a concern.  Their two biochars were cooked at 300° and 500°C.  At 300°C there was no loss of N, with only a slight loss observed at 500°C.  So, the biochar in this study is a much better source of fertility than in the 2nd study in the library.  The authors found big increases in soil P because of the char application in comparison to the fertilizer.  The corn wasn’t so sure. 

Across all 4 growing seasons, corn yields were as good as the fertilizer for the 300°C char and almost as good for the 500°C char, better than the first corn study for sure.  Gold medal quality not quite, but in this case a good option. 

The final paper in the library (Impacts and interactions of biochar and biosolids on agricultural soil microbial communities during dry and wet-dry cycles) compares the impact of biosolids and char on soil microbial communities.  The char is from walnut shells and the biosolids that were tested was the tried-and-true commercial material from Wisconsin -- Milorganite.  This work was done at UC Davis and has Kate Scow as the last author.  You can trust this paper.  This is a little different from the other papers as the char isn’t from biosolids.  However, many have touted the benefits of char for the soil microbial community.  With increasing focus on soil health, it seemed good to add this in.  Here the authors looked at the impact that biosolids alone and biosolids + char had on the soil microbial community as it was subjected to different wet and dry cycles to mimic drought stress.  They used a PFLA (phospholipid–derived fatty acid analysis) to characterize the response to different groups of bugs. They found that the char alone only increased microbial biomass during one measurement interval.  Biosolids increased microbial biomass across all moisture regimes by 55% over the 12 weeks of the study.  The biosolids also helped to mitigate the impact of the wet/dry cycles.  They talk about biochar as a good combination with biosolids, but not so much as a tool on its own. 

The take-home here: biosolids-based biochar seems to fall into the “does not do much harm” category, but it is not clear that biosolids-based biochar does much good though.  Go this way if you have money to burn. But for me, I still like the cake. 


MABA Event Presentations

2020 November Phosphorus 101 Webinar

2020 Summer Webinar Series

2019 Summer Symposium

2018 Annual Meeting & Symposium

2018 Summer Symposium

2017 Annual Meeting & Symposium

2017 Summer Symposium

2017 NJWEA Workshop

2016 Annual Meeting & Symposium

2016 Summer Symposium

2016 NJWEA Workshop