Symptoms

• Clogging of the extraction line

• Incorrect operation of the extraction sludge pumps

• Sand presence in the clarifier

Main causes

• High content of sand or clay

• Low velocity in extraction sludge line

Investigations and analyses

• Measure the sand and clay content in the collected sludge

• Evaluate flow velocity in the extraction pipe

Remedial actions

• Back-wash the clogged line

• Enhance the grit chamber efficiency

• Remove the sludge more frequently, trying to remove curves and valves

• If needed reduce the sludge pipe diameter