Mixing System for Anaerobic Digesters
Maximum Reliability. Zero Digester Downtime.
Landia GasMix delivers a highly reliable mixing solution for anaerobic digesters, designed to keep the digester in operation at all times.
All equipment is externally mounted, meaning there are no rotating parts inside the digester. The complete system, including pumps and nozzles, is installed outside the tank.
This eliminates the need to open the digester for inspection, service or repair of the mixing system.
For the operator, this means:
• Continuous operation with no digester downtime
• No loss of gas production due to maintenance
• Full service access without process interruption
• Improved safety with no confined space entry
• Low and predictable maintenance costs
During operation, sludge is drawn from the bottom of the digester into the GasMix chopper pump, where solids are reduced before being returned to the tank.
This:
• Improves digestion efficiency
• Prevents clogging of pipes and nozzles
• Ensures stable, predictable operation
Mixing is carried out in multiple zones to ensure complete and stable conditions throughout the digester.
• Upper-zone injection entrains biogas, supporting gas release and biological activity
• Lower-zone injection delivers powerful bulk mixing
• Optional top injection prevents surface crust formation
The Digester Mixing System.
Mixing Nozzle UpperCrust Breaker Landia GasMix Nozzle
In the second stage, sludge is injected into the upper part of the digester, where biogas is entrained and mixed into the flow, supporting gas release and process stability.
Depending on digester type and size, a third stage can be included, where sludge is injected into the top zone to prevent surface crust formation.
The mixing process is carried out in stages:
In the first stage, sludge is injected into the lower part of the tank, creating powerful bulk mixing and preventing sedimentation.
Recirculation through the upper and lower nozzles creates rotational flow throughout the digester, ensuring complete mixing.
A key component of the GasMix system is the chopper pump. It delivers the required flow and pressure to the nozzles while reducing solids to smaller particles, supporting a stable and efficient biogas process.
• Mixing Nozzle
Mixing Nozzle
GasMix Nozzle
The uniqueness of the Landia GasMix system lies in the design of the GasMix nozzle, developed over many years to achieve highly efficient performance.
When sludge is pumped through the nozzle, biogas is drawn from the headspace, mixed with the sludge, and re-injected into the digester under pressure.
This creates both horizontal and vertical flow patterns, ensuring complete and effective 3D mixing throughout the
Automated Valves
Chopper Pump
Why Choose Landia GasMix?
• 100% gas-tight system
No loss of methane or CO2
• Easy service and routine maintenance
Fewer man-hours required
• Improved health & safety
No personnel working in the gas zone
• No gas leaks or temperature drop
During maintenance
• Landia chopper pump technology
Effective solids reduction - prevents clogging
• Lower lifecycle assessment
Reduced demands on tank construction
• Minimal space required for service
Compared to other digester mixers
Hot Tap Drilling Installation for Zero-Downtime Digester Upgrades
The Landia GasMix system can be installed without emptying the digester, as all work is carried out externally.
This allows the digester to remain in operation throughout the installation process, eliminating downtime and avoiding loss of production.
Installation begins with positioning the tank wall connections, followed by controlled drilling through the tank wall.
A sealing arrangement is then applied to ensure a secure and leak-tight connection, after which the system is inserted without the need to open or empty the digester.
The result is a fast, safe and cost-efficient installation with minimal environmental impact.
• No Downtime
• Cost Efficient
• Safe and quicker installation
• Environmental Benefits
