Dairy & Slurry
Slurry vs Manure vs Crops
Slurry, manure and crops all work as AD feedstock, but behave very differently in the digester and change what equipment and handling a plant needs.
6 min readRead Guide
Dairy & Slurry
What Can You Put Into a Farm Anaerobic Digester?
Not everything biodegradable belongs in a digester. Here's what UK farm systems commonly use, and why feedstock choice needs deciding early.
6 min read · Reviewed September 2026
Quick Answer
Farm anaerobic digesters can process materials including cattle slurry, manure and suitable plant material. However, what a specific plant can accept depends on its process design and the regulatory regime applying to the site. Adding imported waste or animal by-products can significantly alter the requirements.
Key Points
- Common agricultural feedstocks include cattle slurry, manure and suitable plant material
- Being biodegradable doesn't automatically mean a plant is designed to accept it
- External waste can move an installation into a different regulatory category
- More energetic feedstock isn't automatically better once cost and complexity are weighed in
Common agricultural feedstocks
UK farm-scale AD commonly involves cattle slurry, farmyard manure, plant material, crop residues, silage, and purpose-grown crops on some systems.
- ·Cattle slurry — the most common UK farm feedstock
- ·Farmyard manure
- ·Silage and other crop residues
- ·Purpose-grown crops, on some systems
Can you put anything biodegradable into a digester?
No. Something being biodegradable doesn't automatically mean the plant is designed for it, the pumps can handle it, it's biologically suitable, or it's legally permitted. Feedstock decisions affect gas production, pumping, mixing, digester loading, retention, storage, digestate status and regulation.
What about waste from outside the farm?
This needs particular care. Taking external waste can move an installation into a different regulatory category, and some animal by-products are subject to additional controls. Feedstock should be agreed before plant design, rather than treated as an opportunistic decision later.
Is more energetic feedstock always better?
Not necessarily. Higher gas yield may be attractive, but additional feedstocks can introduce purchase cost, transport, storage, permitting and contamination risks. For many dairy farms, the attraction of slurry-only AD is precisely that the farm already produces the feedstock, without adding operational complexity.
Frequently Asked Questions
Sources
Related AD Guides
Getting Started
What Is Anaerobic Digestion?
The basics of farm-scale anaerobic digestion — what goes in, what comes out, and the infrastructure a working plant actually needs.
10 min readRead Guide
Dairy & Slurry
Can AD Run on Slurry Alone?
Yes — slurry-only AD is already operating on UK dairy farms. Here's what affects gas production, how slurry actually moves through the system, and what it needs to work well.
10 min readRead Guide
Costs & Feasibility
AD Plant Cost in the UK
There's no single reliable price for a farm AD plant — total project cost depends on the plant plus civils, infrastructure, installation and site-specific requirements.
11 min readRead Guide
PLANNING AN AD INSTALLATION?
Need help with the practical side of an AD project?
Charlie Bell Building supports farm-scale anaerobic digestion installations from site preparation and groundworks through to equipment installation and commissioning support.