High-Efficiency Sand Filter for Water Purification

1. Introduction

Sand filters are essential components in water treatment systems designed to remove suspended solids, turbidity, and particulate impurities. They are widely used for their simplicity, efficiency, and cost-effectiveness. By utilizing layered sand media, these filters provide a natural and robust filtration solution for various applications.

2. Design Structure

• Cylindrical Filter Tank: Made of carbon steel, stainless steel, or fiberglass reinforced plastic (FRP) for corrosion resistance.

• Inlet/Outlet Ports: Flanged or threaded connections for easy integration.

• Multi-Layer Filter Bed: Typically consists of coarse to fine graded sand, optionally combined with anthracite or garnet.

• Underdrain Assembly: Ensures uniform water distribution and efficient backwashing.

• Backwash System: Manual or automatic valves with air scouring options.

• Control Panel: Digital or analog interface for monitoring and control.

3. Operating Process

During filtration, water enters the tank from the top or side, passes through the sand bed, and exits at the bottom. Suspended particles are trapped in the upper layers of the sand. When pressure drop reaches a set limit, a backwash cycle is initiated, reversing the flow to clean the media and remove debris.

4. Advantages

• Stable performance with consistent water quality output.

• Low operational cost with long media life and minimal maintenance.

• Easy installation and user-friendly interface.

• Customizable flow capacities to meet different project needs.

• Eco-friendly—no chemicals required for filtration.

• Flexible configurations—can be installed in single or multi-unit arrangements.

5. Industrial Applications

• Food & Beverage water pre-treatment

• HVAC cooling tower filtration

• Textile and dyeing water clarification

• Pulp and paper process water

• Mining and metal processing wastewater

• Desalination plant pre-filtration

6. Key Selection Criteria

• Flow rate capacity

• Water source characteristics (turbidity, solids load)

• Desired outlet water quality

• Filter media type and depth

• Pressure drop tolerance

• Control type (manual, semi-auto, fully automatic)

FAQ

1. What types of sand media are used?

• Quartz sand, garnet, anthracite, and sometimes gravel.

2. How long does the filter media last?

• Typically 2 to 5 years depending on water quality and usage.

3. Can sand filters remove bacteria?

• Not effectively; additional disinfection methods are needed.

4. What is the maximum operating pressure?

• Most designs support up to 0.6–1.0 MPa (6–10 bar).

5. Do I need chemicals for backwashing?

• No, backwashing is typically done with clean water or air-water mix.

6. How frequently should backwashing be done?

• Frequency depends on solids load, typically once every 1–3 days.

7. Is automation available?

• Yes, with differential  pressure sensors and programmable controllers.

8. Can it be used in high-temperature applications?

• Yes, stainless steel versions can handle higher temperatures.