Digestate Dryer Manufacturer in the United States
See how we dry Digestate FibreLooking for digestate dryers manufacturers in the United States? STRONGA builds FlowDrya lines to order at its Hertfordshire works and supplies them to the United States — see the regulatory and economic context below.
FlowDrya digestate dryers are engineered to order at STRONGA's Hertfordshire works and supplied to American anaerobic-digestion operators, though no FlowDrya digestate line is documented on US soil yet. Drying matters here because separated digestate fibre, if it is to be land-applied as a biosolid, must satisfy the federal 40 CFR Part 503 standards, and a Class A product achieved through heat and drying carries the fewest restrictions on where it may go. Stabilising the fibre to a low, even moisture concentrates its nitrogen and phosphate and protects it in storage. Because separated fibre is acidic and ammonia-laden, American digestate machines are supplied with a stainless-steel package.
Supplying the United States
We supply the United States from our Hertfordshire works — we have no documented Digestate Fibre installation in the United States yet.
Regulatory context
Non-hazardous solid waste is regulated under Subtitle D of the federal Resource Conservation and Recovery Act (RCRA): open dumping is banned and municipal solid waste landfills must meet the minimum national criteria of 40 CFR Part 258, but the individual states run the permitting programs and may set stricter rules, so the requirements a drying or waste-processing plant faces vary from state to state.
Source: https://www.ecfr.gov/current/title-40/chapter-I/subchapter-I/part-258 · checked 2026-08
Biosolids and other sewage-sludge-derived materials applied to farmland are governed by the federal Standards for the Use or Disposal of Sewage Sludge at 40 CFR Part 503, which set Class A and Class B pathogen-reduction pathways; a Class A product achieved through heat and drying carries the fewest land-application restrictions.
Source: https://www.epa.gov/biosolids/land-application-biosolids · checked 2026-08
There is no single federal compost standard; instead, marketable compost quality is demonstrated through the US Composting Council's Seal of Testing Assurance (STA) Certified Compost program, which uses the TMECC test methods and is referenced by a growing number of state and municipal purchasing specifications.
Source: https://www.compostingcouncil.org/page/STARequirements · checked 2026-08
Renewable natural gas produced from anaerobic-digester biogas can earn tradable RIN credits under EPA's Renewable Fuel Standard (D3 cellulosic or D5 advanced, depending on feedstock), which strengthens the economics of digestion sites that must also separate and dry the resulting digestate fibre.
Source: https://www.epa.gov/agstar/renewable-natural-gas-agricultural-based-adbiogas-systems · checked 2026-08
Applicable standards: EN ISO 21640, EN ISO 17225-4, EN ISO 18134, US Composting Council STA (TMECC), 40 CFR Part 503.
Economic context
US landfill tipping fees have climbed year on year — the latest national survey by the Environmental Research & Education Foundation (EREF) put the average at $62.28 per ton, roughly 10% up on the prior year, and large or private landfills charge appreciably more — so avoiding disposal is a growing cost saving.
Source: https://www.recyclingmonster.com/article/eref-us-landfill-tipping-fees-soared-10-in-2024/4251 · checked 2026-08
US industrial customers paid an average of roughly 8.29 cents per kWh for electricity in 2025 (EIA Electric Power Monthly, Table 5.6.A) — cheaper than in Europe but still well above the cost of recovered process heat, so a dryer that runs on waste heat and draws little grid power protects the operating margin.
Source: https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a · checked 2026-08
US industrial natural gas is inexpensive by world standards — recent EIA data put it at $4.07 per thousand cubic feet — which favours drying systems designed around gas-fired or biomass-fired heat, or recovered kiln and boiler exhaust, rather than electric heating.
Source: https://www.eia.gov/dnav/ng/hist/n3035us3a.htm · checked 2026-08
The USDA Rural Energy for America Program (REAP) offers agricultural producers and rural small businesses grants covering up to 50% of eligible project cost — up to $1 million for a renewable-energy system — which can offset the capital cost of an on-farm dryer or an associated biogas or heat system.
Source: https://www.rd.usda.gov/programs-services/energy-programs/rural-energy-america-program-renewable-energy-systems-energy-efficiency-improvement-guaranteed-loans · checked 2026-08
Worked illustration (assumptions stated):
A US digestion operator earns from more than the fibre. Renewable natural gas upgraded from the biogas can generate RIN credits under the federal Renewable Fuel Standard, so many sites are already cash-generative before the digestate is dried. Drying then converts a storage-and-hauling liability into a saleable Part 503 soil amendment, animal bedding or solid fuel, avoiding the tankering of wet material and a landfill tipping fee averaging $62.28 per ton on any rejected fibre. Running the dryer on the plant's own combined-heat surplus, or on gas at $4.07 per thousand cubic feet, keeps the operating cost low, and a USDA REAP grant can fund up to 50% of the equipment. Assumptions: incentive eligibility and offtake prices are site-specific.
Figures are indicative and were last reviewed August 2026; energy and disposal prices move — contact us for a current assessment.
Digestate Dryer Manufacturer in the United States — FAQ
Do you have a US digestate drying installation?
Not yet. We will not imply an American digestate reference we do not hold; our documented lines dry digestate fibre, bark and woodchips in Britain, on the identical FlowDrya platform.
How does drying protect digestate's land-application status?
Land application as a biosolid depends on meeting 40 CFR Part 503. Drying the fibre to a stable low moisture supports a Class A pathogen result and concentrates the nutrients, keeping the product within the specification a buyer relies on.
Which rules govern digestate here?
Sludge- and digestate-derived biosolids applied to land fall under 40 CFR Part 503, while the digestion and drying operation itself sits within RCRA and state permitting. A dried, specified product is far easier to place compliantly.
What end markets take dried digestate fibre?
Depending on grade, buyers include arable growers seeking a phosphate-rich soil amendment, livestock yards wanting absorbent bedding, and pellet mills producing a compact renewable fuel. A drier, friable fibre travels economically and blends predictably.
Does the FlowDrya suit corrosive digestate long term?
Yes. The stainless-steel enclosure resists the acidic, ammonia-laden vapour that shortens the working life of mild-steel dryers, giving anaerobic-digestion operators a durable asset with decades of expected service.
How does renewable natural gas improve the economics?
Upgrading biogas to renewable natural gas can earn RIN credits under the Renewable Fuel Standard, adding a revenue stream that helps fund the digestate-handling and drying equipment the site still needs.