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Kärkölä municipality – rationalization of waste water plant

Situation in the beginning

  • two Brush aerators  capacity is not sufficient duringthe peaks
  • Brush aerators demand relatively lot maintenance and are in the end of their working life
  • The flow is not sufficient  part of the sludge lands on the bottom of ring basin
  • Direct feedback connection from the oxygen sensor to the aerator via AC Drive is not possible because the Brush aerator creates water flow

Execution of project

Phase 1 – May 2006

  • Two Waterix AIRIT® 200 aerators are installed in addition to the existing brush aerators
  • Mixing is boosted by Waterix AIRIT® 200 aerators and no sludge lands on the bottom of the ring basin

Phase 2 – December 2006

  • Waterix AIRIT® 200 control by oxygen sensor, 2 mg02/value is set

Phase 3 – 1 H 2008

  • Brush aerators are removed
  • Flow generators and four additional Waterix AIRIT® 200 aerators are installed

Kärkölä municipality – achieved benefits

  • Inexpensive solution compared with fine bubble diffusion (cost + installation)
  • Capacity is sufficient during the peaks
  • No sludge on the bottom of the basin
  • Aerator controls by oxygen sensor – > energy savings
  • No process cut offs during aerator maintenance
  • Easy to add aerators for future capacity needs
  • Better efficiency compared with fine bubble diffusion systems (basin depth 3,5 m)