Interest rising in biosolids
By SEAN CLOUGHERTY
In the midst of record-setting fertilizer prices, farmers are eyeing ways to reduce input costs but maintain productivity in their fields.
One avenue gaining more attention this year is in using municipal biosolids.
“I’m definitely hearing it around the region and moreso globally,” said Mary Firestone, executive director of the Mid-Atlantic Biosolids Association, referring to more interest coming from farmers.
Firestone said with more farmers turning to biosolids for a share of their crop nutrient needs, seeing how it performs firsthand may have them opting for more long-term use.
“It’s likely the calalyst that we need,” she said.
DC Water, which treats the wastewater from about 2.5 million people in Washington D.C. and some surrounding Maryland and Virginia counties since mid-February was sold out of its Class A Exceptional Quality biosolids product branded as Bloom through May, according to Holly Kiser, Bloom’s agriculture sales representative.
“In the spring we usually sell out or get close. This year we sold out before the spring even hit,” Kiser said. “I’m super popular and not popular because when I can’t get people what they want they’re not happy.”
Kiser said growers are using biosolids in concert with commercial fertilizers an animal manure to meet nutrient needs in accordance with their nutrient management plans.
Along with its use in growing field crops like corn, soybeans and hay, Kiser said greenhouse and nursery operators are using it in growing flowers and ornamentals.
It is also marketed to home gardeners, community gardens and landscapers.
John Uzupis, technical services director for Synagro, a Baltimore-based biosolids handler, said that they have also seen an uptick in interest from farmers.
He said new clients are gravitating toward its Class A Granulite product with existing clients holding to both the Class A and Class B products.
“Interest in biosolids use has been strong over the last few years, but farming is a unique business beholden to external challenges such as weather and market volatility,” Uzupis said in a written statement. “Overall, the extraordinarily high price of fertilizer combined with availability issues farmers are experiencing, has increased interest in biosolids use this year.”
Montgomery County, Md., farmer Eric Spates has used DC Water’s Bloom on fields the last three years.
Spates said he hoped to secure enough of the product to cover a third of his overall nutrient needs but with the increased interest, will likely fall short.
“Everybody is looking for something to offset fertilizer costs,” said.
Using biosolids still comes with logistical hurdles, he said. With lower nutrient value per ton, it takes longer to spread than commercial fertilizer.
An applicator spreading chemical fertilizer can cover hundreds of acres per day compared to only about 12 acres per day with the bloom product with Spates’ equipment.
That also means more trips into the field, which can result in compaction issues.
Chemical fertilizer also has the flexibility to customize blends for specific needs.
But, Spates said along with cost, the benefits include building up the soil with organic matter and adding micro nutrients make it a good resource for many of his farm fields.
“It’s kind of the ultimate in nutrient recycling,” Spates said.
Like any nutrient source, biosolids used in excess can lead to negative effects on soil and water quality.
Odor is often another challenge worrisome to farmers by way of nuisance complaints.
Recently, a farm in Trappe, Md., had multiple odor complaints filed against it from nearby residents after municipal biosolids from Ocean City, Md., and byproducts from poultry and seafood processing were land applied last year.
The complaints were heard by the Talbot County Agriculture Resolution Board which is tasked with recommending whether or not the county’s Right to Farm law protects the farm’s practices.
At the committee’s Feb. 28 meeting on the issue, the farm’s attorney said the farmer would cease applying the seafood processing product which appeared to generate the most complaints and future applications of organic nutrients will be incorporated in the soil with conventional tillage instead of the turbo-till practice he had been doing.
In discussing Bloom’s use, Kiser noted no odor complaints have been recorded in the last two years with about 165,000 tons of the product distributed each year.
As a product, Bloom was born about six years ago after DC Water invested in anerobic digesters and a patented thermal hydrolysis system to meet the EPA Class A Exceptional Quality (EQ) requirements, allowing for sale and distribution to the public.
The $470 million project has a 75 year lifespan and a 14 year payback, according to Chris Peot, DC Water’s director resource recovery.
The system has reduced carbon emissions by 50,000 metric tons annually and now generates 64 percent less end product and fewer truck trips, clean green renewable energy, renewable energy credits, and a higher quality soil amendment product as compared to the years prior to the digestion.
Key to the treatment process and high quality Bloom product is the patented Cambi THP technology, a pressurized high heat system.
The first of its kind in North America, the hydrolysis process operates with no external energy — utilizing heat recovery from on-site turbines and acts as a “giant pressure cooker,” Chris Peot, DC Water’s director of resource recovery said.
After solids are separated from wastewater and screened, each batch is heated and pressurized with steam, sitting for about 20 minutes at over 300 degrees F (well above the requirements for pasteurization) and 6 atmospheres of pressure.
The heat kills the pathogens and the pressure bursts the cells, making the carbon a very available food source for the microbes in the digesters, whose job it is to convert organic matter into methane.
“It absolutely obliterates all the pathogens,” Peot said. “The digesters are like the stomach of the city, taking excess carbon and converting it to energy, much like our digestive system does when we eat food.”
Leaders in the regional biosolids industry said the increase in interest also comes as technology has advanced to make more consistent and safer products.
Firestone said most biosolids producers use a multi-stage filtering process compared to one or two steps many years ago.
“It has been remarkable to see how much technology has come to this industry,” said Anne Marek, president of the MABA. “The outlook of what the wastewater treatment process is has definitely progressed from something that used to go to a landfill to go to a beneficial suite of uses. Technology has helped that happen safely.”