Automatic Continuous Sand Filtration

Mobile sand filtration unit from Service in Separation are compact, energy-efficient, that cleans itself continuously.

The filters operate without interruption and deliver high-quality, clear effluent.
It is ideal for both industrial wastewater treatment, process water, and tertiary (effluent) polishing.

Continuous sand filtration as a temporary, mobile system is mainly used in situation where clarifiers are overloaded and effluent qualities are out of range.

How does it work?

Influent flows upward through a bed of filter sand. Suspended solids are retained in the sand bed. At the same time, a continuous internal backwash takes place: contaminated sand is transported upwards, washed, and returned as clean sand while filtration continues without interruption.

Control

Sand circulation and washing intensity are automatically controlled based on pressure drop and water quality. This ensures robust and reliable operation, even under fluctuating loads.

Maintenance

Because the filter cleans itself, no shutdowns or large backwash cycles are required. This reduces operating costs and minimizes maintenance.

Key benefits

• High effluent quality: very low suspended solids, suitable for discharge or reuse.
• Low water and energy consumption: no large backwash cycles required.
• Operational reliability: simple, robust mechanics with few moving parts.
• Fully automated: PLC/SCADA integration with trend logging and alarms.
• Compact: high capacity with a small footprint.
• Flexible: suitable for polishing, tertiary treatment, or membrane pre-treatment.

Applications

• Municipal WWTP – tertiary polishing
• Industrial process water (food & beverage, paper, chemicals)
• Effluent reuse (cooling water, utility water)
• Pre-filtration before UF/RO membranes
• Iron/phosphate removal after coagulation
• Polishing after biological treatment (MBBR or activated sludge)

Process steps

• Influent – water enters via the bottom
• Filtration – suspended solids are retained in the sand bed
• Continuous wash – contaminated sand is transported upwards and washed
• Clean sand return – washed sand returns to the bed
• Effluent – clear water exits via the top
• Sludge – wash water with concentrated solids is discharged