Colloide designs and manufactures Deep Bed Sand Filters. Their unique filter under- drain system is designed to maximise efficiency and life span of the filters.

Colloide filters are designed with a filter bed depth of between 1000—2000 mm, and the media is carefully selected with the correct size, uniformity coefficient, roundness and material qualities.

  • High filtration velocities are achievable, typically in the range of 10-15m3/m2/h.

  • Colloide can design and build systems to suit concrete or steel filter tanks, depending on the plant flow rates and client preferences.

  • The filter can handle high solids loading.

  • The deep bed effectively guarantees a high solids capture and high performance.

  • Colloide's filter under-drain system is designed to reduce the overall height of the filter while maximising the backwash efficiency. Furthermore, it has a very long life and does not block.

  • The coarse media encourages solids to penetrate the bed, allowing the bed to store a large quantity of solids, resulting in longer run times and less backwashing.

  • A central launder runs along the length of the filter and is used to evenly distribute the incoming flow along the filter and then to collect the dirty washwater.

Deep bed sand filters are designed with a filter bed depth of 1000-2000mm, and the media is carefully selected with the correct size, uniformity coefficient, roundness and material qualities. The media is supported on a bed of gravel to provide the necessary support during filtration and distribution of water and air during the filter backwashing process.

The water travels downwards through the filter bed, the solids are captured by the filter media, and the clean water is discharged through the base of the filter.

In order to clean the filters, Colloide uses a state-of-the-art backwashing system, backwashing with air and water. An individual filter is taken off-line, backwashed and then returned to service. The backwashing process takes approximately 2 minutes to complete.

The filters are generally PLC-controlled with an operator interface panel or PC used to allow the operator to view the plant operation and change parameters.

Applications

Water and wastewater

The main function of deep bed sand filters is to remove solids from the incoming water / wastewater.

When used on drinking water, these filters provide an effective barrier to many drinking water contaminants, with excellent removal of turbidity, metals, microorganisms and colour.

When used for wastewater treatment, the solids removal reduces BOD / COD levels in the treated wastewater. These deep bed filters may also be used for nitrate (NO3-N) removal and / or phosphate removal. The filter achieves SS removal, BOD removal, phosphate and / or nitrate removal in a single step.