Equipment
AD Pipework
The shortest pipe route isn't always the best one. Route, bends, valves and future maintenance access all shape what a real AD pipework design looks like.
5 min readRead Guide
Equipment
Pumps and Mixers in Anaerobic Digestion: A Farmer's Guide
The digester gets most of the attention, but pumps and mixers are what actually keep material — and the process — moving.
6 min read · Reviewed September 2026
Quick Answer
Pumps move slurry and digestate through an AD installation, while mixers help maintain suitable material conditions in tanks and digesters. Equipment needs to be selected around the actual duty, including flow, pressure, solids, slurry consistency, pipe length and operating conditions. Correct installation and maintenance access are as important as selecting the equipment itself.
Key Points
- Pumps move material between collection, reception, the digester and digestate storage
- Pump duty needs matching to the actual hydraulic system, not a generic slurry pump
- Mixers help distribute material and maintain consistent digester conditions
- Installation and access for future removal matter as much as the equipment itself
Why are pumps important?
Without reliable material transfer, the biological process can't operate as intended. Pumps may be required between slurry collection and reception, reception and the digester, and the digester and digestate storage, among other process stages.
Why can't you just use any slurry pump?
Because the duty matters — required flow, vertical lift, pipe length, pipe diameter, bends, slurry consistency, solids and operating hours all need considering together. A pump needs to work against the actual hydraulic system it's installed into, not a generic spec sheet.
What about dilution?
AFBI notes that pumping and mixing characteristics are influenced by feedstock dry matter, and that farm slurry can become significantly diluted by yard water and washings — which affects both the biological process and the equipment duty required.
What do mixers do?
Mixing can help distribute incoming material, maintain consistent conditions, reduce settling and improve contact between microorganisms and feedstock. The exact mixing arrangement depends on the digester technology being used.
Why does installation matter?
Even the correct pump can become difficult to operate if installed poorly — isolation, removal, lifting, access, pipe supports, valves and electrical connection all need thinking through at the layout stage. One practical question is always worth asking: how will this pump actually be replaced when it eventually needs to come out?
CBB and specialist pump suppliers
Charlie Bell Building works with specialist suppliers, including TT Pumps, when selecting and installing pumps and associated equipment for farm AD projects.
Frequently Asked Questions
Sources
Related AD Guides
Installation
What Does AD Installation Involve?
Installing an AD plant involves far more than delivering the digester — from site assessment and agreed scope through groundworks, connections, testing and commissioning.
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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.
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Equipment
What Size Digester Do I Need?
Digester size can't be calculated from cow numbers alone — it depends on feedstock volume, dry matter, retention time and the farm's actual energy demand.
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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.