Updated: July 2002
Uniflo Sand Filter (Movable bed type upward flow continuous filter)1. Purpose
The sand filter has become widely circulated in these days, to improve the effluent water quality, and to utilize the water resource. For the conventional sand filter, it was necessary to interrupt the operation temporarily and to wash the sand to recover the filtration capacity. On the other hand, the movable bed type upward flow continuous filter (UNIFLO SAND FILTER) is a newly developed sand filter which allows the continuous filtration without interrupting the operation to wash the sand.
2. Performance and Characteristics
1) It is possible to filtrate the influent suspended solid up to the concentration of approx. 100 mg/l
2) The pressure loss is extremely limited, or is normally 1,960-2,940 Pa
3) It is possible to execute coagulation/filtration treatment.
3. Features
1) Since the filter is back-washed at all times continuously during operation, it is possible to obtain stabilized and high-quality filtrated water.
2) Since the suspended solid contained in the raw water is captured by the clean filter sand, it is also possible to filtrate the high-turbidity sewage.
3) Since the filtration and back-washing are performed continuously, the miscellaneous units for back-washing will not be required and the equipment itself can be simplified, thus resulting in reduced trouble and easy maintenance/control.
4) It is necessary to arrange the limited number of control units, as the equipment uses the continuous back-washing.
5) Since only the raw water pump and compressor are prepared for the drive source, the filtration pressure loss is smaller and more stabilized than that of other method, and the drive consumption is limited, resulting in reduced maintenance cost.
4. Construction and Principle
1) Filtration process
The sewage is raised into the filter bed through the feeder tube and the feed distributor. During this process, the suspended solid is removed, and the filtrated water is collected by the discharge trough.
2) Back-washing process
The filter media is washed together with the filtration of raw water. The contaminated sand is absorbed from the bottom side of the air lift pump, and is mixed with air and water for washing, while it is rising. The back-washing water is separated from the washing filter material by the separator, by which the sand is washed by the sand washer and is returned again to the filter bed surface.
5. Application Field (Achievement)
Sewage treatment water, living discharge water, catering discharge water, food discharge water, wastewater from hospital, night soil treatment water, bilge flooded from land fill, general plating wastewater glass polishing wastewater, chemical factory wastewater, pool water, fish farm water, pre-treatment of raw drinking water, construction road discharge turbid water, etc.
