Multimedia Filtration is the first line of defense in water treatment
Multi-Media Filtration is often used to:
q Reduce the level of turbidity caused by particulate matter that is suspended in incoming process feedwater from a surface, well, or municipal water supply
q Prevent larger particulate matter from “fouling” downstream filtration components
q Prevent suspended particulate matter, such as clay, silt, ferric iron, and oxidized manganese or sulfur, from passing downstream
Suspended particles, whether they are mineral or biological in nature, can foul downstream filtration and process equipment, reducing their effectiveness, or even causing accelerated wear and destruction of pumps, seals, and related equipment. Multi-Media Filtration is often the first line of defense against particles in the 15-50 micron range from entering a process water stream. Depending on the application requirements, tanks are made of Fiberglass Reinforced Plastic (FRP) or Steel. Tank sizes, number of units, and control functions depend on flow requirements and duty cycles.
Advantages of Multi-Media Filtration Include:
q Relatively Inexpensive with no Recurring Cost of Consumable Chemicals
q Easily Cleaned and Maintained
q Resistant to Fouling (Clogging)
q Filtration Media is Inexpensive and Long-Lasting
q Multi-Media Filtration Technology is among the Oldest, Well Understood, and Tested forms of Water Treatment
q Systems are Robust with no Moving Parts inside the Tanks
q Control Valves are Modular and Designed for Operational Flexibility
Multi-Media Filtration Operating Cycles:
Service Cycle: Filters remove solids from water. The water flows downward through the media and is clarified. The solids accumulate in the media bed, while the purified water passes through to downstream processes.
Backwash Cycle: When the filter begins to clog or when the head loss (pressure drop) though the bed increases, flow rates are reduced. To prevent solids “break through“ and the resulting degradation of water quality, the Service Cycle flow is reversed, fluidizing the media bed. The reverse flow is directed, by the control valve(s) to drain, carrying with it, the particulate matter that has built up during the Service Cycle. The flow required is specific to the media and is essential to properly cleaning the Media Bed.
Continuous Versus Periodic Service: In most operations, demand for process water is tied to work shifts. If those work shifts consume all 24 hours each day, and the demand for process water is constant, the Multi-Media system may need to be designed to operate in stages across multiple tanks, so that the Backwash Cycle can occur in one or more tanks while the other tanks are operating in the Service Cycle mode. If the demand for process water is periodic, Backwashing can usually occur during off hours, which decreases the size and complexity of the Multi-Media Filtration system. Our standard products are designed to accommodate either scenario up to 400 gallons per minute; however, specific applications may require additional design modifications.
Other Types of Media:
In addition to sand and various sizes of gravel and garnet, many other specialized forms of media are available which are designed to remove contaminants such as iron, tannins, and a wide variety of other chemical constituents and toxins. Please consult our water treatment specialists for more information on the treatment and/or removal of specific contaminants.
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