Dynamic Sand Filters

Excellent treatment systems for the removal of solids and other contaminants from a water/wastewater stream.

About The Technology

Colloide‘s Dynamic Sand Filter is always on line, continually filtering the incoming water while continually backwashing a small portion of the sand bed.

Summary of the Dynamic Sand Filter process:

  • The feed water is fed into the filter at the base of the active sand bed through the distribution ring.
  • It then flows upward through the downward moving sand bed where the solids are filtered out.
  • The clean filtrate exits the filter through the overflow weir. The continuous reject flow of washing water is discharged through a separate outlet.
  • The dirty sand is continuously removed from the active sand bed thanks to the action of the air-lift pump. This pump draws the contaminated sand from the bottom of the filter body.
  • A mixture of sand, dirty particles and water is transported upward through the air-lift pipe into the washing chamber at the top of the filter.

These filters can also be designed as Ammonia Removal filters, denitrifying filters and/or phosphorous filters.

All wetted parts are in stainless steel AISI 304L. Special construction materials available upon request.

Solutions for installation in a concrete basin of several basic filter inserts is available, as is that for single concrete filters of various sizes.


Why our Dynamic Sand Filters?

Absence of any mechanical moving parts.

Higher suspended solids content in feed, high efficiency in removing fine solids.

Very low pressure drop across the filter, gravity feed is possible in many instances Easy maintenance thanks to the internal sand air-lift system.

Unique continuous back-wash system using counter current variable velocity washing.

Colloidal particles efficiently removed through simple in-line dosage of coagulants.

Simple plant with no backwash water storage and backwash pumps.

Coagulation, flocculation and filtration in one step thanks to the deep active bed.


  • Polishing of process waters for recycling oil, phosphorus and ammonia removal.
  • Tertiary filtration.
  • Denitrification.
  • Cooling tower water filtration.
  • Drinking water filtration.
  • Algae removal.
  • Pre-membrane filtration.
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Derryloran Industrial Estate, Cookstown, BT80 9LU