LanceMix® Sludge Mixing Systems

The LanceMix^® system has been designed to effect the homogeneous mixing of the sludge within the digester to ensure uniform temperature throughout the sludge and also to prevent the formation of a surface scum layer.

Bio gas is drawn from the gasholder cover by the gas compressors. After the bio gas is pressurised by the compressors it is returned to the digester for injection into the sludge at depth, via one of the stainless steel lances. Five lances are fitted, but only one lance works at any time. The lances work in a sequence and for the time set in the plant control system.

Each lance is fitted with its own pneumatically actuated, anti static, fire safe ball valve. Each actuator is fitted with open and close limit switches. When a lance operating sequence change is signalled, a new lance valve must be proved open by its limit switch before the old lance valve is permitted to close. Valve closure must also be proved or a fault is indicated.

The bio gas compressors will shut down in the event of the following faults :

• Low bio gas delivery side flow rate
• Low compressor seal water flow rate