Donovan's Dairy

2,000 cows | Mechanical Separation

Dairy yard is flood washed after each milking using freshwater 2 x 9000 L Food Wash Tanks. Dairy wash-down and yard effluent is collected in a rectangular sump. The sump was constructed to function as a trafficable solids trap, however the separation boards were removed when the mechancal separator was installed. A front-end loader can access the trap from either end. Approximate capacity 120 m3. The sump contains a submersible effluent pump and a bridge mounted submersible effluent pump and a bridge mounted stirrer.

Prior to the pump operating, the stirrer agitates the sump to re-suspend sand and manure that has settled out of solution. The stirrer, pump and separator are controlled by a PLC. Agitated effluent is pumped up to the Press Screw Separator (PSS). The PSS is elevated on a platform to enable the separated effluent to gravitate to the storage pond, and the solids to stockpile underneath the separator. The separated solids are removed 2-3 times per week and stockpiled in an area not accessed by the cows. The separated solids have a similar consistency to wet sawdust.

Application areas include: 

  • Liquid effluent is injected into centre pivots and applied to pasture during the summer irrigation period. The effluent is shandied with irrigation water at a rate of 4%
  • 4 kW helical rotor pump transfers effluent to the pivots and travelling irrigator
  • 100 ha of area available for effluent irrigation
  • A contractor spreads solids back on the property every 18 months. A travelling irrigator is used to irrigate effluent during the winter period
  • 20 ha of area available for effluent irrigation
  • slide