High-quality suspended particle filtration from a small-footprint filter bed with no moving parts or backwash equipment requirements.
DynaSand® is a continuous upflow vertical sand filter for low-power, low-maintenance filtration of potable water and tertiary treatment of final effluent discharge from sewage and industrial wastewater treatment plants.
DynaSand® delivers high-quality suspended particle filtration from a small footprint filter bed with no moving parts or backwash equipment requirements.
As the water flows upwards through the filter bed to the filtrate outlet, precipitated particles are deposited on the sand grains. Flocculation chemicals may be injected directly into the DynaSand® inlet stream if required. The sand is continuously circulated by an airlift pump and impurities washed from the sand in the separate sand washer, to be discharged for additional treatment or disposal.
DynaSand® handles high concentrations of suspended solids efficiently without requirements for settlement tanks and has a 90% smaller footprint than the equivalent horizontal filter bed.
With the addition of metal salts, DynaSand® can provide phosphorus removals down to 0.1 mg/l whilst also removing effluent BOD and TSS down to 10 mg/l. Read about how DynaSand® has been protecting the lakes of Växjö in Sweden for over 20 years.
DynaSand® provides efficient removal of fine suspended solids, such as silts and peat, from reservoir, river and lake water, prior to sterilisation treatments where required.
DynaSand® is suitable for final treatment and polishing of sewage and industrial wastewaters prior to final discharge. Using aluminium or iron-based flocculants, highly effective removal of fine suspended solids and reductions in phosphate content can be achieved to meet the strict environmental standards.
With the addition of metal salts, DynaSand® can also provide phosphorus removal down to 0.1 mg/l.
DynaSand® ensures precipitation of metallic ions and their removal through sedimentation and filtration, providing low residual ion concentrations and meeting strict environmental discharge criteria.
The DynaSand® filter is based on the counter flow principle. The water to be treated (red arrow) is admitted through the inlet distributor (1) in the lower section of the unit and is cleaned as it flows upwards through the sand bed, prior to discharge (blue arrow) through the filtrate outlet (2) at the top. The sand containing the entrapped solids is conveyed from the tapered bottom section of the unit (3), by means of an airlift pump (4), to the sand washer (5) at the top.
Cleaning of the sand commences in the pump itself where impurities are separated from the sand grains by the turbulent mixing action. The contaminated sand spills from the pump outlet into the washer labyrinth (6) in which it is washed by a small counter current flow of clean water. The separated solids (brown arrow) are discharged through the wash water outlet (7), while the grains of clean sand (which are heavier) are returned to the sand bed (8). As a result, the bed is in slow, constant downward motion through the unit. Compressed air for the sand pump is provided by via the control panel.
Water purification and sand washing both take place continuously enabling the filter to remain in service without interruption.
* effluent standards quoted to 95%ile
** annual average