Two types of Filtralite® Pure filter beds at Gäddvik (SE)
Gäddvik´s drinking water treatment plant produces water for 65.000 inhabitants
The new drinking water treatment plant in Gäddvik, located just outside Luleå, was built in 2013-2015 and produces water for 65,000 inhabitants. The raw water comes from groundwater, with groundwater continuously refilled through the production of artificial groundwater.
Surface water is filtered through Filtralite® to produce artificial groundwater
Water from the Luleå River is pre-filtered through rapid filters where turbidity is reduced before the water is pumped to the infiltration basins. These rapid filters use Filtralite Mono-Multi as filter media.
Filter beds are 2-meter deep and are used with a filtration rate of 15m/h. Turbidity is reduced from 2 to 0.5-0.6 NTU. No flocculation normally takes place before filtration, but the plant is technically organized for this option to be enabled if necessary.
It takes more than a month for the water from the infiltration basins to reach the groundwater natural reservoir.
Filtralite® is also used to produce drinking water
After being pumped, groundwater goes through filtration filter beds. Just upstream of the filters, pH and alkalinity are adjusted using lime and carbonic acid. Flocculant are also added.
In total, 8 filters using Filtralite Mono-Multi as filter media are working on the plant. These beds are 2-meter deep and filtrate water at 5m/h, achieving a reduction of turbidity up to 0.02-0.03 NTU.
Backwashing takes place every 6 days.
pH and alkalinity are adjusted once more and finally the water is UV-desinfected.
More details are available here.