Fenno Water Ltd Oy products

We manufacture pressurised suspended solid filters for steel tanks. The filter cylinder is placed inside a pressurised tank. The filter cylinder is rotated during the backwash flushing. The flushing water nozzles are installed on the cylindrical wall of the external tank. Flushing sludge is removed automatically according to the timer programme or pressure measurement. The flushing takes a very short time, only lowering the pressure in the purified water piping for a moment. We also sell pressurised continuous solid matter filters where the filter surface is cleaned with a rotary brush. This model does not need flushing water because the solids brushed off the filter surface are removed from the filter by the inlet water pressure. In this filter type, brushing and the removal of solids are done automatically, controlled by pressure measurement.

In terms of sand filters, “continuous” means that the sand bed of the filter is continuously pumped through the washer using an air pump, from the bottom of the bed to the surface of the bed. Continuous flushing ensures an even flow of flushing sludge with lower flows. No flushing water and reject sludge basins are needed for storage in this case. Flushing air requirement is divided over a longer period of time, and there is no need to use a flushing water pump. Chemical precipitation can be used before filtration to improve the filtering efficiency. These filters are available for steel and concrete tanks. The filter works automatically, controlled by the pneumatics control panel. Four sizes are available of the steel tank models. Concrete tank models are designed on a case-by-case basis.

We design and manufacture sand filters based on gravitational pressure. The filters are installed in steel or concrete basins. Inlet water is brought into the filter through piping and automatic valves or through a channel and automatic closing plates. The thickness of the sand bed is slightly more or less than 1.5 metres. The sand bed is flushed with pressurised backwash air and pressurised backwash water. The durations and intervals of air and water flushing of the sand bed vary according to the sludge type. Flushing air and water are fed in evenly through special nozzles placed in the flushing piping or intermediate floor underneath the bed. Flushing sludge is discharged into the overflow channel by rising the water level during flushing. The sludge is led out of the channel into the sludge or reject water process. The operation of the filters is controlled by automatic valves and/or automatic closing plates.

We manufacture lamella pack clarification devices with the lamellae installed into a frame, i.e. a pack. Water flows in from the bottom of the lamella pack from both side, and the clarified water exists from the top into overflow channels and out of the clarification basin. Fast and slow mixing devices can also be combined with the basins connected to the clarification unit. The lamella pack is delivered to the purification plant pre-installed and lowered into a concrete basin. Lamella pack clarification devices are available for square, rectangular and round basins. Rotary scrapers with central traction or chain scrapers according to the tank size and shape are used for scraping sediment from the bottom. Our delivery includes overflow channels that are pre-installed into the lamella pack. Inlet piping can also be included in the delivery.