Energy-Efficient Effluent Filtration

Effluent filtration serves for increased removal of suspended solids (SS), BOD, COD, phosphorus (P) and nitrogen (N). About 20 % of German effluent is filtered.

The following filters are in common use:

• Multi-layer and multi-chamber sand filters with periodic water and air backwashing consume around 2.0 kWh/(PE•a) power;
• Continuous moving bed sand filter (e.g. our CONTIFLOW® Sandfilter CFSF) consume about 1.5 kWh/(PE•a);
• Microstrainers with a mesh size of 10 – 100 micron (e.g. our RoDisc® Rotary Mesh Screen) consume ca. 1.0 kWh/(PE•a);
• Membrane Bio-Reactors perform not only biological treatment, but also excellent filtration.

Where precipitation or flocculation is required, sand filters should be provided. Multi-layer sand filters are used at large wastewater plants, while continuous sand filters are more economic at small to medium-size plants.

Microstrainers are less effective than sand filters, but they are significantly less expensive and consume less power.

The following table provides a comparison: