Durable Sand Filter for Industrial & Municipal Water Treatment

1. Working Principle

A sand filter uses a multi-layer bed of granular media (typically quartz sand) to capture and remove suspended solids from water. Water flows through the filter bed under pressure. Impurities are retained within the sand layers while clean water flows out. Periodic backwashing is performed to clean the filter media by reversing the flow and flushing out collected debris.

2. Component Materials

• Filter Housing: Carbon steel with epoxy coating, stainless steel (SS304/316), or FRP

• Filter Media: Graded quartz sand, anthracite, or garnet

• Internal Piping: UPVC or stainless steel

• Backwash Valves: Cast iron or stainless steel with electric or manual control

• Underdrain System: High-strength ABS or stainless steel nozzles

• Instrumentation: Pressure gauges and sight glass, stainless steel

3. Applications

• Municipal drinking water pre-treatment

• Industrial cooling water systems

• Agricultural irrigation water filtration

• Pretreatment for reverse osmosis systems

• Swimming pools and aquaculture tanks

• Wastewater reuse and tertiary treatment

4. Selection Parameters to Confirm

• Flow rate (m³/h or GPM)

• Water quality (turbidity, suspended solids concentration)

• Filtration accuracy (20–100 microns standard)

• Tank diameter and height

• Backwash method (manual, automatic, air-assisted)

• Operating pressure and temperature requirements

5. System Features

• Robust construction for long service life

• High filtration efficiency with minimal pressure drop

• Automatic or manual backwash system

• Easy to install and operate

• Scalable design for multi-unit installation

• Compatible with various filter media types

6. Operation & Maintenance

• Regularly monitor pressure differential

• Initiate backwash when pressure drop exceeds 0.1 MPa

• Check and clean nozzles and internal piping during maintenance

• Replace filter media every 2–3 years based on usage

• Inspect valves and seals for leakage or wear

• Ensure uninterrupted inlet flow during filtration and stable backwash supply

FAQ

1. What is the minimum micron rating for sand filters?

• Typically 20 microns, depending on media size.

2. Can I use sand filters for oily water?

• Sand filters are not suitable for oil-heavy fluids; consider multimedia or coalescer filters.

3. Is a sand filter suitable for well water?

• Yes, especially for removing sediments and iron particles.

4. Do sand filters require continuous supervision?

• No, automatic backwash systems reduce manual intervention.

5. Can multiple sand filters be installed in parallel?

• Yes, to handle higher flow rates or provide redundancy.

6. How is the backwash triggered?

• Either by time, differential pressure, or manually, based on the control system.

7. Is filter media replacement costly?

• No, quartz sand and anthracite are relatively low-cost and long-lasting.

8. What is the typical backwash duration?

• 5–10 minutes depending on filter size and contamination level.