Sand filter design and standardisation using CFD

Our customer the Dutch drinking water company Vitens wants to standardise the design of it's rapid sand filters. Many design types exist (circular, rectangular, with different dimensions). Using a very realistic CFD model, we assessed:

• The filtration cycle: is loading over the bed equally distributed?
• The backwash cycle: can we shorten or optimise the backwash?

Methodology

We applied a 3-phase CFD model that very realistically modelled different full-scale sand fitlers in 3D.

Outcomes

The placement of inlet/outlet gutters, nozzles, filter dimensions, filter aspect ratio's, water levels, .... were assessed. We could propose optimal inlet configurations that led to a more homogeneous distribution (and loading) over the filter.

We also proposed improvements for the bottom part of the filter (nozzles and space under the filter).

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