MidAtlantic Biosolids Association

Biosolids Research Updates: Blurbs by Dr. Sally Brown

A High Note for Biosolids

I decided to end the year on a high note (pun intended).  This month’s library takes us into the great and expanding unknown.  I am not talking about black holes here- rather the realm of kush aka cannabis.  I will dispense with trying to sound cool for the rest of the library.  It is way too much of a stretch.  

As of writing this library summary cannabis is legal for recreational use in 10 states, 7 of which tax purchases in retail stores.   If you consider states where medical use is legal- the majority of the country is included.  Canada- that big progressive country up north went full legal just recently.

Legalization has taken an industry that has been operating under cover for decades and brought it- or is working to bring it to light.  Cannabis sales in Washington State in 2018 totaled $534 billion with excise tax revenues of over $120 billion (https://data.lcb.wa.gov/stories/s/WSLCB-Marijuana-Dashboard/hbnp-ia6v/).  That is a lot of material and a lot of money.  The point for this library is that growing this material is a potential huge market for biosolids and composts.  How big and how best to enter it are questions that remain to be answered.

The library has typically focused on peer reviewed research.  Because cannabis is still illegal on a federal level the agronomic research as has been done for just about every crop, with associated extension bulletins is completely lacking.  Land grant universities rely on federal funding and federal funding essentially prohibits any research on banned substances.  While the peer reviewed literature didn’t turn up anything on growing cannabis in biosolids- it did provide some insight on the industry that can help in figuring out the best ways to enter this market.

Home growers

The first article reports on a survey of growers.  Here the authors went to Facebook to distribute their survey.  They got responses primarily from men (76.4%) and found that a significant number across all surveyed had grown their own (56%).  The survey included respondents from states where laws range from fully illegal to home cultivation allowed to home cultivation + dispensaries are legal.  A significant number of those who had grown in the past were still growing and again- this went across the legal spectrum.  Of those that grow about half throw out their leftover plant material while the other half compost it.  What this article tells us is that there is a significant market for growing materials for the home or hobby grower.  There is also likely a significant market for compost feedstocks from those growing operations.

Environmental impacts

It may be a hobby for some- but it is more than scraping by for others.  The cannabis industry is big business with associated environmental impacts.  As legal cultivation is a relatively new phenomenon we can look at Northern California for an understanding of what is involved in growing grass.   Humboldt and Mendocino counties were the center of cannabis cultivation.  It was believed before the legalization revolution really got underway, that CA growers supplied up to 79% of the pot consumed in the US (article 2) and most of it was grown in these counties.  When cultivation was illegal, much of it took place on federal or state forest lands.  Growers would clear parcels and grow on hillsides and in the woods.  Article #2 provides anecdotal information on the environmental repercussions of outdoor growing operations.  Impact to water quality as a result of unrestricted use of fertilizers and pesticides is discussed as are carbon emissions associated with clearing trees and planting weed.  The authors note that the high irrigation water requirements for cannabis cultivation in this region meant illegal use of fresh water diverted from streams.  That illegal water use has resulted in some of these streams going dry.  Illegal growing outdoors without the benefit of regulation has had big and bad environmental impacts.  The article includes many quotes and information from the grey literature- again showing it is hard to write science about stuff that is going on below the radar. 

The third article provides an evaluation of energy use for indoor cultivation.  Growing illegally outdoors may suck for the environment- but indoor growing isn’t exactly carbon friendly.  The article goes through the various aspects that use energy for indoor cannabis cultivation.  See figure 1 below:

It turns out that lighting (33%), ventilation and dehumidifiers (27%) and air conditioning(19%) account for most of the energy use.  The article, from 2012, estimates that indoor cannabis production used 3% of California’s total electricity or 1% of the electricity used in the US as a whole.  That is about as much power as is used in 1 million CA homes.  Production and distribution of cannabis resulted in emission of 15 million tons of CO2 or about 3 million cars’ worth.  You know how 1 ton of food scraps diverted from landfill to compost gives you about a ton of CO2 credits?  Well each kg of cannabis produced emits 4.3 tons of CO2.  So illegal outdoor cultivation is an environmental disaster and indoor cultivation is an incredibly high user of energy.  Here is a comparison in MJ per $1000 of product of different crops.

The authors of this 3rd article argue that outdoor cultivation can produce as high quality a product as indoor cultivation if done properly.  They also argue that much of the energy used for indoor cultivation is above and beyond what is needed. 

What do we know?

So now in most places cannabis cultivation is legal.  Growers range from individual hobbyists to professionals.  Growing operations take place outdoors and in greenhouses.  In both cases- growing cannabis has been terrible for the environment.  To me this means that these growers need us!  The 4th article in the library is from cannabistraininguniversity.com.    Not sure if you need to take the SATS to get admitted there.  It is all about the benefits of growing cannabis with compost.  Read this and you realize how much potential there is for growth and compost use in this sector.  And how little you would learn as compost professionals from enrolling at Cannabis U. 

Avid readers of the Biobull might remember a study that we did with hemp.  Looks and smells like the real deal but with lower THC content.  We tested Tagro and Tagro + char against Happy Frog- a growing media popular in Humboldt, CA.  We got an exceptional response.  The Happy Frog plants are on the right.  

After that piece was published in the Biobull Tagro got an order for 800 yards from a grower outside of Ellensburg and two phone inquiries from other growers.  They were sold out and so couldn’t provide the material.  According to Dan Eberhardt a number of smaller growers come into the plant to buy their Tagro.  The staff have heard that the Tagro works great.

It would seem that these growers would like to ‘grow green’.  There are no organics standards for cannabis cultivation.  It seems like high time (there I go again) to develop products that specifically target these growers.  Ask compost producers in Northern California what it takes to enter a market.  Look at the resources for your state where it is legal to identify growers to partner with.  This is a growth industry that needs to grow greener.  Let us help.

Finally- the last article in the library is just the nonsense that we’ve come to expect.  It is a recent article from Environmental Science & Technology- a high profile journal that loves crying wolf.  The article talks about expanding cannabis use and pharmaceuticals derived from cannabis that are entering the market.  These compounds- the article cautions will and are already entering our nations’ wastewater systems.  They present a potentially dangerous new class of pharmaceuticals and by products that could pose a risk.  The authors detail the chemical structures of these compounds and discuss why we need to worry. 

Don’t let this bring you down.  It is just the normal stuff that we have to deal with.  At least it may get people’s minds off of PFAS.  In the meantime- start thinking about this great opportunity and have a lovely holiday. 

If you want to see the citations for the articles above, click here.

See you in February.  

Sally Brown, University of Washington


Biosolids NewsClips: Connecting Biosolids to the World

Kingston Breached Contract with Maker of Fertilizer Pellets, Appeals Court Rules
Kingston, NY (1/10/2020) - The NY state appeals court has ruled the city of Kingston breached its original contract with Aslan Environmental Services that made fertilizer pellets from sludge processed at Kingston's wastewater treatment plant. The 2005 amendment extending that deal was also determined to be void. 

Greene County Residents Try to Block Large Waste Ponds
Bath Township, OH (1/12/2020) - “A Bath Twp. resident is seeking sanctions against the Ohio Environmental Protection Agency and Dovetail Energy, asking the agency to revoke Dovetail’s permit to build large ponds in Greene County to store biosolids.”

Savannah Close to Implementing Long-Term Solution for Bio-solids Facility Odor Issue
Savannah, GA (1/9/2020) - In May 2019, Savannah City Council approved the emergency purchase of an odor control system for the President Street Bio-Solids Facility; that was meant to be a temporary solution, to buy time to come up with a permanent solution.The permanent odor control solution, which has been installed, is a two-stage chemical scrubber made from fiberglass reinforced plastic which includes a mist eliminator for each stage, blower, supply and interconnecting duct work, chemical re-circulation system, and instrumentation and local control panel.

PFAS Filtration System Explained
Marinette, WI (1/10/2020) - Tyco Fire Products LP invited government officials from the City of Marinette, City of Peshtigo and Town of Peshtigo to tour a Marinette facility that houses a Granular Activated Carbon (GAC) filtration system for PFAS compounds. The facility offers a look into the technology and machinery that local communities could use to address PFAS contamination.

Infamous ‘Poop Train’ Could Roll Back into West Jefferson County
Birmingham, AL (1/7/2020) - Biosolids from New York may be hauled to Big Sky Environmental once again. After the outcry of residents complaining about the smell of the biosolids that sat on the train tracks near Big Sky in 2017, residents are concerned about the potential of it happening again. Biosolids are considered fertilizer which cannot be refused entrance into the state. The Alabama Department of Environmental Management has called a hearing to make changes to the state’s solid waste program.

Twice a Year, Human Waste Goes Back to the Land
Dakota County, MN (12/27/2019) - Sewage going to Metropolitan Council Environmental Services’ Empire Wastewater Treatment Plant, is processed into biosolids and spread on farm land in Dakota County. The Met. Council will be constructing a roof for their biosolids storage area and making other improvements to the biosolids pads. These investments will help expand the plants biosolids storage capacity and improve the drying process.

Springfield Residents Fight Stench with Signs: 'No Sewer Sludge in Our Neighborhood'
Springfield, TN (12/27/19) - “Tycowa LLC signed a five-year contract with Metro Nashville for the beneficial reuse of biosolids, which includes shipping it from Nashville to Springfield.” Now people living near the biosolids storage facility are speaking out against the facility because of odor issues.

EPA to Settle Clean Water Act Violations from Biosolids Land Application
Mid-West, USA (1/3/2020) - “Recently, the U.S. Environmental Protection Agency (EPA) announced that it completed four federal enforcement actions in Iowa, Kansas, Missouri and Nebraska to settle Clean Water Act violations that resulted from land application of biosolids in 2019. The four Region 7 facilities were among nine announced nationally Dec. 18… The violations addressed by these settlements include the land application of biosolids when pathogens, such as E. coli and Salmonella, and heavy metals, such as cadmium, lead, nickel and molybdenum, exceeded limits.” 

Scientists Validate a New Technology that Transforms Sewage Sludge into Fertilizer More Efficiently
Granada, Spain (1/10/2020) - “Research Group RNM-271 of the Department of Chemical Engineering at the University of Córdoba, in conjunction with Research Group RNM-270 of the University of Granada, has successfully validated a new technology that transforms wastewater sludge more efficiently. The system, tested on an industrial scale, avoids the foul odors that are generated during the composting process. In addition, it reduces by up to two months the time needed to stabilize and sterilize the organic matter from the sludge and convert it into fertilizer.” The technology uses a series of movable and semi-permeable membranes, under which the composting process takes place. These covers allow molecules such as carbon dioxide to pass through, while blocking others such as ammonia, which causes the foul odors.

Victoria Plans to Ship Tons of Sewage Biosolids to Richmond
Harltand, B.C. Canada (1/3/2020) - “The Capital Regional District (CRD) is seeking proposals from trucking companies to carry dried biosolids from Hartland to Richmond. The request for proposals closes Jan. 22, and the CRD is striving to choose a company near the end of February.” The CRD is seeking hauling companies able to transport the biosolids. This is part of a larger, long-term biosolids plan they hope develop by mid-2023. 

Biosolids Blockade Ends, Waste Won’t be Dumped at Shuswap Bison Ranch
Kamloops, B.C. Canada (1/6/2020) - Biosolids from Kamloops will not be transported and dumped at the Turtle Valley Bison Ranch. The city is working closely with Arrow Transport to find other locations for the product, though nothing has been identified to date.

Compost Location Found?
Okanagan-Similkameen, BC, Canada (1/6/2020) - The Regional District of Okanagan Similkameen is considering purchasing property near the Campbell Mountain Landfill for a new organics and biosolids waste composting facility. A new grant program has been identified that could fund up to 83 per cent of the expected $17.2-million price tag for the facility, which would utilize “in-vessel” composting to minimize odors.


Biosolids TOPICs: Interesting Ideas Connected to the World

When Biosolids is Hot Stuff

On nearly every Thanksgiving Day over the past 30 years, a moment inevitably comes to me when I recall, with a slight shudder, the great Thanksgiving Day conflagration of biosolids compost that threatened to shut down Philadelphia’s international airport. A huge pile of Philadelphia’s unscreened compost had caught fire spontaneously on that windy holiday morning and was billowing acrid smoke across the runway approach path. The FAA got involved, asking should it halt flights into the airport.  It did not; the compost was spread out and sprayed with water, and the fire and smoke were finally extinguished.

Spontaneous combustion.  This is a serious issue with any operation in which biomass is stored in big piles for extensive periods. That is just as true for biosolids products as it is for other organic materials. The National Fire Protection Association (NFPA) reports over 14,000 fire department responses annually to fires believe to have started spontaneously (Investigating Claims Involving Spontaneous Combustion). A quick Google Search of news articles on “spontaneous combustion” reveals an amazing array of such fires.  Tempura flakes spontaneously combusted in Wisconsin in 2019 , which recalled spontaneous nacho chip fires (Flakes Aflame, Spontaneously combusting tempura flakes spark blazes, recalling 2018 nacho incident”). MBM, or meat and bone meal, is vulnerable, as described in the Japanese Failure Knowledge Database (”Spontaneous ignition of meat and bone meal under storage caused due to fermentation with rain water”), and by the French (Self-ignition of animal meal). Soy meal is similarly at risk: Spontaneous combustion sparks fire in previously flooded mountain of soya beans.  Manure is a major culprit, as explained by state extension agencies ( e.g., Delaware ).  International news services have covered fires in Spain (Manure pile spontaneously combusts to spark 13,000-acre wildfire, Spanish authorities say), as well as the U.S.  (Spontaneous combustion concerns lead to warnings over height of chicken manure piles and  Crap's Spontaneously Combusting in Upstate New York.)  And hay is, too, at major risk for spontaneous combustion (Firefighters battle combine blaze to save crops ); the U.K. reports that damages due to haybale fires rank above other causes for insurance payouts (Fires cost farming industry more than rural crime).

Closer to home, several items in the home are culprits.  Oily fabric rags are worst, as in the news story from November 2019, Improperly stored rags cause house fire in New York State and ‘Spontaneous combustion’ causes North Hollywood auto shop fire  in California. And in today’s high tech world, an emerging source of spontaneous combustion is lithium batteries (Lithium Batteries Rechargeable batteries in your favorite devices can ignite and burn down your house). The solid waste industry is close to this issue, recommending management of transfer station pits (see A combinational approach). A less appreciated spontaneous combustion risk is laundry. Recently washed, dried and folded cotton towels seem to be a culprit (Could your laundry burn your house down? Fire started when washing spontaneously combusted after being folded and put away).  This is true, too, for  commercial laundering facilities, leading one manufacturer to provide this to brochure to customers: Preventing Laundromat Fires - Spontaneous Combustion in Dryers.

Spontaneous combustion of wood piles is a major issue, and many kinds are vulnerable, including wood chips, bark, yard trimmings and wood biofuel pellets. A review article from nearly 20 years ago, Self-Heating In Yard Trimmings: Conditions Leading To Spontaneous Combustion, concluded “the bigger the pile, the lower the ambient temperature at which SC may occur.” It usefully pointed to earlier research by the coal industry (SPONTANEOUS COMBUSTION OF COAL: “There are many factors which may contribute to spontaneous combustion including: pile size, atmospheric moisture content, wind, coal type, internal heat and oxygen transfer.” The emergence of a vigorous marketplace for wood pellet biofuel has focused research into methods of avoiding pile fires: Recent Health and Safety Incident Trends Related to the Storage of Woody Biomass: A Need for Improved Monitoring Strategies. This arises from a few incidents that have caught the industry’s attention, especially a sequence of fires at a Georgia manufacturer (Wood pellets 'spontaneously combust' at Logistec). Such landmark events have pointed to the importance of industry guidance documents, such as Self-heating Hazards of Biomass Materials, describing equipment operational risks,  and Early Detection of Spontaneous Combustion in Pellet Mills, describing product storage risks, for which remote monitoring for pile temperatures and carbon monoxide are recommended.

What does all of this have to do with biosolids? If you are truly a hands-on, field-tested biosolids managers you know the answer. Many biosolids products are subject to spontaneous combustion. Air-dried granules, heat-dried pellets and biosolids compost are all prone to spontaneous combustion; it’s not a matter of if, but of when.

Conference papers, journal articles and technical manuals on the mechanisms of biosolids fires and the best practices for preventing and managing fires are rare. To its credit, the US EPA covered the risk of self-heating and spontaneous combustion in the 2000 Guide to Field Storage of Biosolids, but in cursory fashion. In 2006, at the 11th, European biosolids conference,  Steven Manchester, owner of a specialty consultancy BRE Global Ltd., discussed how to characterize the propensity of different biosolids products to self-heat (“Application of Self-Heating Test Data to the Safe Handling and Storage of Dried Sewage Sludge”), and in 2007 at the 12th annual conference Manchester discussed the risk of thermal dryers (“Fire Risk Assessment of Sewage Sludge Dryers”), but these papers appear no longer accessible. Recent journal articles are not terrifically helpful, with the article Flammability properties of thermally dried sewage sludge confirming dried sludge will burn, and Self-heating of dried wastewater sludge telling us dried biosolids can self-heat.

Research on non-biosolids residuals has been more robust than biosolids and provides some information on the mechanisms that may be involved with biosolids self-combustion.  One study of dried sludges from industrial treatment explored the complex interplay of moisture content, air flow/permeability and particle size.  The report,  Self-heating of dried industrial wastewater sludge: Lab-scale investigation of supporting conditions, explained ”[t]he higher the O2 concentration, the higher the solids heating rate. More added water prolongs the exothermic phase… The sludge particles size strongly determines the strength and extent of the heat release, indicating that surface reactions are taking place. In pelletized particles, limitations to water and air permeability mitigates the reaction course.”  Another study, also on industrial sludges, showed an influence of iron on self-heating. Iron is used for phosphorus and odor control in some wastewater plants, and the biosolids in these plants run high in iron concentrations.  Research suggest that iron reactions may accelerate self-heating to the point of combustion: Self-heating of dried industrial tannery wastewater sludge induced by pyrophoric iron sulfides formation.  Research on wood pellets (Self-Heating and Spontaneous Combustion of Wood Pellets during Storage)  shows that slow temperature rise from oxidation to the boiling point of water can initiate a pyrolytic (absent of oxygen) reaction that causes rapid self-heating: “the heat generated from the pyrolysis reaction is too large to be dissipated, leading to the accumulation of heat in the silo center,” a condition it terms “thermal runaway.” 

How ought we manage risks of spontaneous combustion?   We need to turn to our network of colleagues who are “in the trenches.” For operations, Brandon Gott offers the GHD Fire and Explosion Hazard Assessment and Training and lectures on “Dust Hazard analysis & Thermal Dryer Design Safety Considerations.”  Robert Pepperman, Synagro’s director of product sales (AllGro biosolids compost and Granulite biosolids pellets), advises his large, nationwide customer base on management of bulk products distributed to agricultural and horticultural users, including storage challenges. Other fire-tested colleagues of ours include Chicago’s Dan Collins, compost consultant Craig Coker (see his January 2019 BioCycle article Managing Compost And Mulch Fires), and Inland Empire’s (California) Jeff Ziegenbein.

A first step is to know your product and the vulnerable aspects of your production process. Laboratory characterization of the biosolids product for aspects of flammability can inform storage monitoring. Synagro has developed for its own company’s laboratory protocol for judging the tendency of biosolids pellets to heat during storage. Pellets with high iron and oil contents are flagged for higher risk. Outdoor storage presents more risks of spontaneous combustion than covered storage, but storage facilities need to be built with fire risks in mind. Inland Empire’s indoor composting has smoke monitors that compel immediate actions to dismantle and cool piles when smoke is detected, and happily such events have been rare because Inland Empire aggressively moves compost through the entire plant in 60 days. Inland Empire also has written procedures kept close at hand for fire emergencies, and these plans have been reviewed with local fire fighters.  Compost and pellet customers are advised regularly by both Synagro and Inland Empire to avoid long storage and to use products promptly, and they are instructed to carefully break into hot spots and douse them with water.

Here is additional advice culled from written work and interviews applicable to mitigating spontaneous combustion of biosolids compost and pellets: 1. Keep pile size small, (e.g., under 8 feet tall) which allows for heat dissipation. 2.  Do not let piles become too dry, as moisture will slow heat build-up, and not too moist, as moisture spurs heat-generating microbial activity. 3. Do not allow piles to age too long, as old piles tend to trap heat and decompose. 4. Constantly monitor piles for hot spots, using automatic equipment (such as thermocouples and infrared detectors), as appropriate, and, also, visual inspection for smoldering areas, and once heat is detected, take action, as in pile breakdown. 5.  Anticipate adverse weather factors that increase risks, such as rain, strong winds and warm air temperatures and increase inspections accordingly during such weather.

Even so, unexpected events of spontaneous combustion can occur. One customer of Philadelphia’s compost asked for reimbursement for a wooden fence the customer needed to replace. What I observed when I visited the site was an event of spontaneous combustion in which a 2-inch layer of biosolids compost had been overlain by an inch of triple screened hardwood mulch, effectively sealing the biosolids from heat dissipation after a rainfall had stimulated microbial heating. Smoldering biosolids compost led to a burning fence posts, which led ultimately to a burning fence. Had I not seen this for my own eyes, I would not have guessed this phenomenon possible. In a similar way, had not a security camera at a sushi restaurant in Wisconsin recorded ignition of tempura flakes, the cause of the restaurant fire would have remained unknown. Biosolids, like sushi, is a complex material, and no less so when the Biosolids is Hot Stuff.


Symposiums & Presentations

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