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Dried layer manure in store
Guide · Layer manure

Dry layer manure within 48 hours

Take the water out quickly and the manure keeps its nitrogen, loses more than half its weight and becomes a stable product.

Forged Innovation · 29 September 2026 · 5 min read

Try it

More water, more heat: where drying stops paying

Material
Pays for itselfTipping point ▸ Energy in the solids, 3–5 kWh/kg 20%40%60%80%95%035812 Water content as producedDrying heat, kWh per kg of solids –
Pays for itselfBreak-even, ~78–85% waterToo wet, above ~85% water
Water to remove, per tonne–
Drying heat, per tonne–
Drying heat, per kg of solids–
Energy in those solids3–5 kWh

Each tonne dried to 80% dry matter (20% water) at 0.8–1.0 kWh per kg of water; the line is the mid case, the shaded band the range. Typical water content as produced: broiler litter ~30%, layer manure ~70%, separated fibre ~70%, slurry 90–98% (Defra RB209 slurry categories of 10%, 6% and 2% dry matter; 90% is the thickest).

70%

of fresh layer manure is water

48h

to 60–80% dry matter in a ventilated drying tunnel

625kg

of water removed from every tonne dried to 80% dry matter

62%

less weight to store and move

Why speed matters

The nitrogen in fresh manure is mostly uric acid, and microbes need water to break it down. Dry it past about 60% dry matter within roughly 50 hours and the breakdown barely starts, so the nitrogen stays in the manure where it has value. Defra’s Code of Good Agricultural Practice recommends clearing belts two or three times a week and notes that ventilated drying tunnels reach 60–80% dry matter in under 48 hours. The mechanism in detail →

What drying does to a tonne
StateMoistureMassWater removedWeight saved
Fresh from the belt70%1,000 kg——
60% dry matter40%500 kg500 kg50%
80% dry matter20%375 kg625 kg62%

Per tonne at 70% moisture (300 kg of dry solids). Only water is removed.

Where the heat comes from

Practical dryers use 0.8–1.0 kWh of heat per kilogram of water, so taking a tonne to 80% dry matter needs about 500–625 kWh. The heat source sets the running cost:

House exhaust airFree warm air over belts or through a tunnel; suits partial drying
Biomass or recovered heatNeeded for high dry matter consistently, especially in winter
Heat from the manure itselfPyrolysis of dried manure supplies the heat to dry the incoming material
Indirect heating and permitting

An indirectly heated dryer, where hot water or air passes through heat exchangers and the drying air never touches combustion gas, keeps the dryer exhaust and any combustion flue as separate, measurable streams. That is the arrangement UK permitting is built around.

Other manures compared
Material (typical)Dry matter as producedWater to evaporate per kg solidsDrying heat per kg solidsVerdict
Broiler litter~70%~0.2 kg~0.1–0.2 kWhLittle drying needed
Layer manure~30%~2.1 kg~1.7–2.1 kWhThe sweet spot: dry fast at source
Separated fibre~30%~2.1 kg~1.7–2.1 kWhFeasible with a reliable heat source
Cattle or pig slurry~2–10%~8.8–49 kg~7–49 kWhSeparate first

Taking each to 80% dry matter at 0.8–1.0 kWh per kg of water. Slurry dry matter from the Defra RB209 standard categories (2%, 6%, 10%). Manure solids typically hold 3–5 kWh per kg.

What dry manure makes possible

Stable storageNo heating, compacting or breaking down in store
Lower haulage and feesMost fees and freight scale with weight and moisture
A saleable productPelleted or sold as fertiliser, moved to where nutrients are needed
A processing feedstockThe right start for pyrolysis: heat plus a stable biochar
Nitrogen keptValue stays in the product
Less to moveUp to 62% lighter at 80% dry matter

Getting it right

  • Match removal to drying. Size the dryer for the daily flow from belts cleared every two to three days.
  • Keep it moving. Wet layer manure is sticky and abrasive; hoppers, augers and conveyors have to be designed for it.
  • Size the heat for winter. Exhaust air is weakest when the manure is wettest.
  • Measure it. Moisture in and out proves the system works and gives buyers and regulators a record.
How we can help

Handling, drying and heat, designed together

We design the handling that keeps wet manure moving, the heat and mass balance that sizes the dryer, and ZEDE on-farm pyrolysis that supplies the drying heat from the manure itself.

Book an auditSee ZEDE

Read next: April 2027: where will 600,000 tonnes of poultry litter go?

Sources

  1. Defra, Code of Good Agricultural Practice for reducing ammonia emissions
  2. Best Available Techniques conclusions for the intensive rearing of poultry or pigs

Energy figures are engineering approximations: the latent heat of water sets the floor, and practical consumption depends on dryer design, air temperature and heat recovery.