Common Faults And Solutions Of Multi-media Filters During Operation

reason :

(Accumulation, aging, adsorption saturation)

Or the influent pretreatment failed.

Uneven water distribution (clogged filter head, deformed filter plate)

Solution :

Backwash or replace the worn-out filter media

Enhanced pretreatment (adjusting coagulant dosage, adding sedimentation tanks)

Inspect the water distribution system (clean the filter heads, replace damaged filter plates).

2. The pressure difference between the inlet and outlet is too large (>0.15MPa)

 reason :

(Impurities accumulate, biofilm grows)

The influent turbidity is too high (>20 NTU).

Incomplete backwashing or filter media with excessively small particle size

解Solution :

Combined air-water backwashing (with acid soaking to treat iron and manganese scale)

Shorten the filtration cycle and add pretreatment equipment (bar screen, sedimentation tank).

Replace with filter media with slightly larger particle size

 reason :

(Insufficient water/gas supply)

Incorrect backwashing sequence (air washing to loosen contaminants was not performed first).

Uneven distribution of backwash water/air (pipe blockage, valve malfunction)

 Solution :
Optimize backwashing parameters (air wash intensity 18-25 m³/(m²・h), water wash intensity 8-12 L/(m²・s))

Strictly follow the sequence of "air washing → combined air and water washing → water rinsing".

Inspect the backwash system (clean pipes, calibrate flow meters)

 4. Filter media leakage (filter media particles are present in the effluent)

reason :

(Insufficient gradation and thickness)

 Filter head damaged, filter plate cracked

Backwash intensity is too high (flow rate is too high)

Solution :

Replace damaged filter head and repair cracked filter plate

 Re-lay the support layer (total thickness ≥ 300mm).

 Reduce the backwash flow rate (control it at 15-20 m/h).

5. Abnormal noises or vibrations during equipment operation

 The inlet pump head is too high (water flow impacts the filter layer).

There is air inside the pipe (cavitation phenomenon).

Backwash water pump/air compressor malfunction (impeller wear, loose bearings)

Solution :

 Reduce the inlet water pressure (control the inlet pressure to ≤0.3MPa).

Exhaust air and check pipe seals

Overhaul power equipment (replace worn impellers and bearings)

 Regular maintenance :

Clean up debris around the equipment weekly and check valve flexibility.

Calibrate the instrument monthly and replenish the filter media (when the height drops by more than 50mm).

Clean the water distributor and check the motor/pump lubricating oil every quarter.

nspect the anti-corrosion coating every six months and replace any aging seals.

Standard operating procedure : Strictly follow the backwashing procedure and avoid frequent start-ups and shutdowns of the equipment.