Filtering stage: The Fiber Disc Filter is composed of thread wound trapeze units. 18 trapeze units join to form a round disc. The number of discs defines the volume of the filter.
During filtration, the contaminated water flows through the filter tank, across the threads that are wound around the discs, and into a central collecting pipe. The water flow is spread out evenly across the whole disc area. The initial step of the filtration process occurs at the first contact of the water with the stretched upper threads. This layer is the first barrier to the dirt. Further filtration occurs as the water flows through the micron channels inside the many layers of threads. The structure of the threads, their designed surface area and the material’s winding characteristics (tension, gaps, number of layers, etc) enable the smallest suspended solids to be intercepted and adhere to the threads. The result is a remarkable, fine filtration.
Backwash stage: The Fiber Disc Filter has an effective backwash self-rinsing system, activated either by time intervals or differential pressure. The backwash mechanism functions by utilizing high pressure water jets that create turbulence and movement of the threads layers. The high pressure water jets from the washing nuzzle penetrate the winded fibers and hit the disc base. The water then bounces back through the fiber layers, collects the dirt on its way and ensures the contaminated water is drained at the bottom of the filter vessel. To guarantee an efficient wash, and an even distribution by the water jet flow across the whole disc area, a combined movement of the nuzzle arm and the discs themselves has been developped. The disc rotates in a variable speed, while the nuzzle arm moves in a straight direction back and forth.
Each backwash sequence takes about 8 minutes, and uses only 1.5% of the filtration cycle’s overall water flow.