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CESCO offers a few different kinds of gravity filters.
Upflow Filter:
The upflow media filter offers high bed loading for solids removal and fine removal of solids and colloidal silica. This design is used extensively on river water for pretreatment for cooling water or boiler makeup water. It can remove 3 times the solids of conventional downflow media filters. It operates at 6 gpm/sq ft for most applications. It is used as a standard in the brine industry.
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Main Components of the Upflow Gravity Filter |
Key benefits over conventional clarification/sand filtration include: installed cost is less, total automation and minimum levels of chemical addition (1-4 ppm) keep operating costs low, requires 75% less space, demineralizer resin life is lengthened due to a process stream virtually free of suspended solids and metal sulfates such as alum. Removal of colloidal silica to levels of <0.1 mg/l eliminates cost of cleaning silica from turbine blades.
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This graph demonstrates the effectiveness of the upflow filter in removing total suspended solids. Curves marked "A" show influent and effluent levels on a 760 gpm system. Note that the effluent levels did not exceed 0.45 mg/l , while the influent varies from 25 to 100 mg/l. Curves marked "B" show a similar effectiveness in removal of suspended solids in a 1,200 gpm system. Effluent quality remained below 0.4 mg/l, while the influent quality varied from 13 to 32 mg/l. |
Contaminant particles are removed via an adsorbtion mechanism, rather than mechanical straining, resulting in the ability to remove submicron particles. It is ideal for dirty river and lake feed water process streams, boiler feed pre-treatment, injection water, chlor-alkali plants, colloidal silica removal, SDI reduction, color removal, iron removal, and ion exchange & membrane system protection. It is also used for removal of hardness precipitation in brine service.
The capacity of the upflow filter system ranges from 60 to 1,000 gpm. Multiple units can be coupled to accommodate any larger flow requirements. By forcing the collected solids deep into the media, the upflow media filter achieves greater operational cycle time. Filter media types can vary or even be combined for maximum efficiency in a given application. Options include silica sand, garnet and anthracite coal. It is available in vertical open top or pressure vessels.
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These five 13' diameter upflow gravity filters each
produce 800 gpm from the Savannah River. The
effluent water is consistently <1 NTU and < 5APHA
color units and is used for total plant process water. |
Model details:
| Materials of Construction: |
Carbon Steel, Coated Steel, Stainless Steel |
| Maximum Flow: |
1,000 GPM |
| Maximum Pressure: |
300 PSI |
| Minimum Flow |
60 GPM |
| Minimum Pressure: |
0 PSI | High Rate Downflow Sand Filter:
The High Rate Downflow Sand Filter offers high performance filtration and longer operating cycles for greater economy and efficiency. It uses an advanced design to allow operation at high flow rates of 12 to 20 gpm per square foot of filter area. The filter's innovative distribution system controls velocity and hydraulic balance within the filter protecting the media during high rate operation.
The capacity of the High Rate Downflow system ranges from 60 to 3,500 gpm. Multiple units can be coupled to accommodate any larger flow requirements. By forcing the collected solids deep into the media, the High Rate Downflow Sand Filter achieves greater operational cycle time. Filter media types can vary or even be combined for maximum efficiency in a given application. Options include silica sand, garnet and anthracite coal. Available in vertical or horizontal configurations, this high rate filtration system is designed for effective removal of oil and suspended solids from sea water, cooling water and oil field brine. It is also ideal for treating industrial wastewater, tertiary sewage and mill scale.
Standard designs available, as follows:
| Materials of Construction: |
Carbon Steel, Coated Steel, Stainless Steel |
| Maximum Flow: |
3,500 GPM |
| Maximum Pressure: |
300 PSI |
| Minimum Flow |
60 GPM |
| Minimum Pressure: |
50 PSI |
Nitrate Ion Exchanger Filter:
This unit is used to remove nitrates from drinking water supplies in areas that experience nitrate leaching in well waters. An anion exchange resin is used and regenerated with brine to reduce the nitrates in exchange for chlorides on the resin.
The latest technology is employed for regenerating the ion exchange resins to reduce the amount of salt and waste water. In the Southern California area, disposal of waste brine is becoming very expensive and utilizing techniques that minimize the amounts of salt and waste water are required. Additionally, the use of counter current regeneration is necessary to obtain the highest efficiency and lowest nitrate leakage from the resin.
Benefits of using Nitrate removal units:
- Counter current regeneration to best utilize salt and regeneration water with the addition of packed bed or resin hold down methods to reduce waste water volume.
- Rinse water recycle tanks to allow for reuse of low salt content water and reduce the waste volume to drain.
- Fully Automated control panels using PLC logic to control the operation of the NRU.
- Blending of feed water and treated water to obtain the lowest cost operation.
Softener Filters:
Designed to soften produced water, by using an appropriate ion exchange media.
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