Better biogas starts before digestion
Feedstock handling and dewatering can determine up to 30% of your methane yield – before the reactor ever starts. We engineer what happens first.
Most biogas plants are engineered from the reactor outward
They invest in anaerobic digestion technology, gas upgrading, and CHP units. The feedstock handling gets whatever is left in the budget — a screw press here, a standard pump there.
The result: inconsistent loading, excessive water in the digester, unpredictable retention times, and yield 15–30% below what the feedstock actually contains. The problem is not the biology — it's the front end.
We build from the feedstock in. Getting the front end right is the single highest-return investment in any biogas plant.
Haarslev Engineering Principle
Six reasons to start upstream
Every improvement in feedstock quality compounds through the entire process. These are the gains that show up in the operating numbers.
Higher Methane Yield
Better-separated, higher-solids feedstock ferments more completely. More organic matter goes to gas, less is wasted as undigested residue.
Lower Pumping Energy
Dewatered sludge moves in screw conveyors, not centrifugal pumps. Removing water early cuts energy consumption at every downstream step.
Reduced Chemical Dosing
Consistent feedstock composition means fewer conditioning chemicals. Predictable inputs produce predictable biochemistry.
Stable Digester Loading
Eliminate the process variation that disrupts microbial communities and suppresses yield. Steady in, steady out.
Easier Digestate Management
More water removed before digestion means drier, more stable digestate — simpler to handle, store, and spread.
Smaller Reactor Volume
Higher total solids concentration means smaller hydraulic retention volume is needed for the same throughput. Capital cost drops.
What Haarslev delivers
Engineered as a system, not a collection of machines. Every component is sized and positioned for your specific feedstock, flow rate, and dry-solids target.
- Screw presses & belt presses
- Disc and paddle dryers
- Depackaging & pre-sorting systems
- Mixing & homogenisation tanks
- Heat exchangers for sludge pre-heating
- High-dry-solids pumping & conveying
Whether you're building new or retrofitting an existing plant, Haarslev supplies individual machines or complete pre-treatment systems — with full integration support.
How it works — four steps to reliable yield
Receive & Sort
Depackaging, screening, and pre-sorting remove contaminants before they reach your process. Consistent input from the first step.
Pre-treat & Dewater
Screw presses and centrifuges pull water from primary sludge and biowaste, increasing dry-solids content to target specification.
Condition & Mix
Mixing systems blend multiple feedstocks to target composition — balancing carbon-to-nitrogen ratio, pH, and solids consistency.
Feed to Digester
Controlled, metered feed at specified solids content. The digester receives exactly what it needs — nothing more, nothing less.
Modular by design. Scalable by intent.
New installations
Complete pre-treatment systems designed from the ground up — sized for your specific feedstock mix and plant capacity.
Retrofits
Drop-in improvements to existing plants. Screw presses, mixers, and heat exchangers integrated with your current digester without disrupting operation.
Single machines
When you have a specific bottleneck — dewatering capacity, feedstock sorting, dry-solids mixing — we supply the right machine, not the whole plant.
Engineered for real plant conditions
Biogas feedstocks are abrasive, corrosive, and variable. Our equipment is designed for those conditions — not for a laboratory with controlled inputs.
Wear-resistant contact surfaces, sealed bearings, CIP-compatible cleaning, and remote monitoring capability are standard. Maintenance windows are short by design.
The same engineering, applied elsewhere
Better biogas starts with a conversation
Tell us your feedstock, your capacity, and where you are in the project cycle. We'll tell you where the value is — and what it takes to capture it.