Symptoms
Air flow rate reduction
Increased headloss in the air line
Main causes
High dust content in the air
Oil content in the air due to air compressor faulty operation
Rust presence in the air pipeline due to the condensing moisture
Organic material growth or solids precipitation over air diffusers
Solid deposition over air diffusers during aeration interruption
Investigations and analyses
Check the dust, rust and oil content in the air flowing to the diffusers
Check breaks presence in the air pipeline through which mixed liquor could enter during aeration interruption
Remedial actions
Keep air compressors as much regularly operated as possible
Check regularly the air filtration system
Install oil trap on the air compressor
Periodical maintenance of the air pipeline
Enhance degritting and screening