Multi-media filters are core equipment in water treatment systems used to remove suspended solids, colloids and other impurities. Their daily maintenance is crucial to ensuring effluent water quality and extending equipment life. The following are the key tasks and specific operating points for daily maintenance of multi-media filters:
1. Operation monitoring and parameter adjustment
Flow and pressure monitoring
Flow control : Set the water inlet flow rate according to the design parameters to avoid overload operation resulting in decreased filtration effect or media loss.
Pressure observation : Regularly record the inlet and outlet pressure difference. If the pressure difference exceeds 30%-50% of the initial value (such as rising from 0.05MPa to 0.08MPa), backwash immediately or check for blockage.
Water quality testing
Influent water quality : Monitor indicators such as turbidity and SS (suspended solids concentration). If the influent turbidity suddenly increases (e.g. >10 NTU), adjust the backwash frequency or pretreatment measures in advance.
Outlet water quality : Test the turbidity of the outlet water daily to ensure that it meets the standard (usually ≤1NTU). If it exceeds the standard, check for problems such as medium compaction and filter layer disorder.
2. Backwash operation and cycle management
Backwash process
Air washing (optional) : First, introduce compressed air (about 5-10 minutes) to loosen the filter material and enhance the backwash effect.
Water washing : Backwash at 2-3 times the design flow rate for 10-15 minutes until the water is clear.
Forward wash : After backwashing, switch to forward water inlet to flush out residual impurities (about 5 minutes) to ensure the stability of the filter layer.
Backwash cycle determination
Fixed cycle : set according to water quality and operating experience (such as backwash once every 24 hours).
Dynamic adjustment : If the pressure difference rises rapidly or the effluent water quality deteriorates, shorten the backwash interval; if the pressure difference is stable and the water quality is good, it can be appropriately extended.
3. Filter material maintenance and replacement
Filter material inspection
Regular sampling : Check the filter media layer height, color and impurity content every quarter.
Compaction treatment : If the filter material is agglomerated, it needs to be broken up by mechanical stirring or high-pressure water gun. If it is serious, it needs to be replaced.
Loss replenishment : If the thickness of the upper filter material (such as anthracite) decreases by more than 10%, new material must be added.
Filter media replacement standards
Expiration of service life : Filter media such as quartz sand are usually replaced every 3-5 years, depending on water quality and operating intensity.
Severe pollution : When the filter material is contaminated by oil, organic matter, etc. and cannot be restored by backwashing, it needs to be replaced as a whole.
4. Equipment Cleaning and Anti-corrosion
Tank cleaning
Internal flushing : During annual maintenance, use a high-pressure water gun to flush the inner wall of the tank to remove attachments.
External rust prevention : Check the tank body welds, manholes and other parts, remove rust from the rusted areas and apply anti-corrosion paint.
Accessories maintenance
Check the water distributor : ensure that the water distribution holes are not blocked and are evenly distributed to avoid partial failure of the filter media due to biased flow.
Valve sealing : Regularly test the sealing of the water inlet valve and backwash valve to prevent internal leakage from affecting the filtration effect.
5. Preventive maintenance measures
Preprocessing optimization
Add a flocculation sedimentation tank or dosing device in front of the multi-media filter to reduce the entry of large particles of impurities and reduce the filter material load.
Winter protection
In northern regions, equipment pipelines need to be insulated to prevent freezing and cracking; water in the tank must be drained when out of use.
Spare parts management
Stock up on commonly used accessories (such as filter caps, seals, and pressure gauges) to ensure quick replacement in case of failure.
6. Recording and Data Analysis
Run log
Record daily water inlet flow, pressure difference, backwash time, outlet water quality and other data to form a trend analysis chart.
Exception handling
If the pressure difference remains high or the outlet turbidity increases suddenly, investigate the cause (such as filter material failure, valve failure, etc.) based on historical data and formulate a corrective plan.
7. Safety Precautions
Operation specification : When backwashing, ensure that the pressure in the tank is released before opening the manhole to avoid high-pressure splashing and injuring people.
Electrical safety : Check the control cabinet wiring regularly to prevent short circuit or leakage.
Protective equipment : Wear goggles and gloves during maintenance to prevent filter dust or chemicals from contacting your skin.
Through systematic daily maintenance, the operating stability of the multi-media filter can be significantly improved, the failure rate can be reduced, and the service life of the equipment can be extended, ensuring the long-term and efficient operation of the water treatment system.
