The SuperSand Filter is an original Nordic Water product. It was invented, patented and developed by a direct predecessor of Nordic Water. It has been a great success with more than 25,000 units installed worldwide. It is now recognized as the state- of- the art in sand filtration.
The technology centre has always been in Sweden. The unique characteristics of the DynaSand made it possible to use it as a process tool. The technology centre in Sweden has developed and patented the following proprietary technologies:
- Continuous Contact Filtration
- Phosphorus removal
- BOD/COD removal
- Nitrogen removal
- Two stage filtration for highest purity
- Activated carbon treatment
The filters are made as freestanding units in stainless steel or reinforced plastic, with various filter areas and filter bed depths. DynaSand filters are also manufactured as units to be built into concrete tanks.
The SuperSand filter is a compact filter without moving parts. No rinsing water supply tanks, sludge water tanks, rinsing pumps or automatic backwashing systems are required.
The standard SuperSand filter system consists of a cylindrical filter container with a conical lower section. The inlet pipe, distributor, air-lift pump and the sand washer are built into the container as standard. A SuperSand filter plant consists of a number of parallel filter units which match with the capacity required. The filter units are connected via an array of pipes to distribute the inflowing water, and to drain the filtrate and the wash water.
Units for installation in concrete tanks
SuperSand filter plants with high throughput quantities are generally made of concrete. In this type of construction, several filter units are integrated in a single concrete tank and form a connected filter bed. Cones attached to the floor of the tank ensure that the sand bed is distributed evenly. SuperaSand concrete filter plants can be designed for filters of any surface area required.
Processes / applications
The most simple form of filtration is mechanical filtration, i.e. filtration without filter aids. Mechanical filters retain suspended filterable matter and are used as:
- Filter steps after final sedimentation tank for retaining floating sludge flocks (e.g. bulking sludge or scum)
- Filter steps after industrial waste water treatment (e.g. neutralisation) for retaining floating metal hydroxide flocks
- Partial flow filtration in cooling water circuits
- Filter steps in steel and rolling mills for precipitating coarse and fine scale in water circuits.
Thanks to the continuous operation of DynaSand filters, the filter can cope with fluids with a high ratio of solids.
Contact filtration (flocculation filtration) is characterised by the addition of precipitants (e.g. Al- or Fe- salt solution) to the supply pipeline of the filter. The goal is to flocculate the matter in the filter bed, which retains primarily colloidal, organic and inorganic compounds and coarse, difficult to filter, particles. Real dissolved water contaminants (e.g. orthophosphate) are also precipitated and retained.
Contact filtration is primarily used when treating surface water to create drinking and industrial water or to eliminate phosphorus in municipal sewage treatment plants; phosphorus concentrations < 0.1 mg/l are reached in the outlet of the DynaSand filter.
Biologically activated filtration
The filter material in the SuperSand filter is especially suitable as a carrier for a biofilm. The filter bed can be used to degrade BOD/COD and for nitrogen reduction by colonising micro-organisms. This is a significant development which offers new areas of application for the purification of waste water and drinking water.
The SuperSand Oxy and SuperSand Deni systems work according to the same continuous process principle as the tried and trusted SuperSand sand filter.