Renergi VBH Water Treatment System

Sand filter's central role

The condensate, which is contaminated by particles, first passes through the trap tower where large particles are filtered out in a lamella system. The lamella system is sufficiently large that no precipitants need to be added. The bottom sediment from the trap tower is pumped out.

From the trap tower, the substantially clean water passes to an open sand filter, which is the central component. The condensate passes slowly through the sand bed where the smaller particles are separated and is finally collected in the clean water tank. The clean water is then fed into the normal system.

Backspolning

Ju mer förorenat sandfiltret blir desto högre blir tryckfallet genom sandbädden. Detta visar sig genom att vattennivån i sandfiltret stiger. När vattennivån har nått ett givet maximalläge indikerar en flottör att sandfiltret behöver backspolas. Vid backspolning pumpas vatten från klarvattentanken, tillsammans med luft från en blåsmaskin, in i botten av sandfiltret och fördelas via munstycken jämt över bädden. Genom luftinblandningen fluidiseras sanden, och vattnet transporterar bort alla föroreningar till fälltornets så kallade samlingstank. Efter backspolningen pumpas samlingstankens förorenade vatten till fälltornets lameller och därmed är backspolningsprocessen är avslutad.

Backflushing

The higher the content of impurities in the sand filter, the greater the pressure drop becomes across the sand bed. This is evident when the water level in the sand filter rises. When the water level has reached a pre-defined maximum level, a float indicates that the sand filter needs to be backflushed.

In backflushing, water is pumped from the clean water tank together with air from a blower into the bottom of the sand filter and distributed evenly across the sand bed by nozzles. With the infusion of air, the sand becomes fluid, and the water carries all impurities to the trap tower's collection tank.

After the backflushing procedure, the collection tank's contaminated water is pumped to the trap tower's lamellae and the backflushing process is complete.

Static filter with stationary bed

The open sand filter has the advantage, compared with a continuous filter, that it is static and remains stationary during the filtering process. This results in a high degree of particle separation. Measurements on which the particle content is 3-5 mg/l are common.