Multimedia Filter System – Alternative to Sand Filters

Multimedia filter system can be used as the alternative to sand filter system. It adopts FRP vessels (also available for stainless steel or carbon steel vessels) as vessels and anthracite coal, sand and garnet as filter media.

It is used to reduce the level of SDI (Silt Density Index). TTS (Total Suspended Solids) in incoming water. Suspended solids include small particles, such as silt, clay, grit, organic matters, algae and other microorganisms. Only remove the suspended solids, can reduce the high-pressure drop and guarantee the effectiveness of downstream filtration equipment such as precision filters, reverse osmosis membranes, EDI, UV as well as ion exchange polishing.

A multimedia filter system structure.
  • Filter Tank. Our FRP tanks (including universal FRP tanks and FRP tanks with upper loading and lower discharge port) are popular during multimedia filter system. Stainless steel tanks are available.
  • Media. This system includes different types of media, including anthracite coal, sand and garnet as media. Other media are available if you needed.
  • Water distributors. Upper and bottom distributors may needed in this system. The bottom distributors can prevent media from escaping, while the upper distributor can enable uniform water distribution.
  • Multiport control valves. This device can reduce your pipeline placement and make the system stable and smart running. Manual and automatic valves options are provided.
  • Flowmeter. It is installed on the drain outlet to control the backwash flow rate and prevent the media from escaping to the drain.

Compared with sand filters, multimedia filter system is composed of three filtration medias in different porosity, which can guarantee trap and retain all particles from large to small orderly. It has higher filtering efficiency and saves occupying are for the projects.

Besides, the backwash system, media depth and bottom distributors arrangement can guarantee the sediments filtered out throughout without losing the filtering media. In this way, the system service life is extended.

Treated Elements

  • Silt
  • Clay
  • Grit
  • Organic Matters
  • Algae
  • Other microorganisms

Water Quality

  • Reduce SDI < 3
  • Reduce turbidity < 0.2 NTU
Working Principle

Arrangement. In the multimedia filter system, there are multiple graded media layers. The most common multimedia filter consist of sand and anthracite coal as the filter media. Where the larger and lighter media (anthracite coal) is placed at the top and the smaller and heavier media (sand) at the bottom. This arrangement can enable large contaminates are filtered out of the water before smaller contaminates and the filtration efficiency for the volume of filter media is increase.
The whole system including filter and backwash stage.

Filter. When the running system, the waters to be filtered enters the tank from the upper distributors and impurities are captured by the multiple layers of medias, which large impurities are captured by the upper layers and small impurities are captured by the bottom layers. Then the filtered water are enters next process from outlet.

Backwash. When the contaminant materials build up too much that either the water flow is hindered or the filtered water quality can not achieve set standard. It should start to backwash. The backwash running is opposite to the filter system, which can remove both large and small contaminants from the drainage outlet.

Filter, backwash and wash condition of multimedia filter system.
  • Suspended solids and turbidity reduction
  • Iron and manganese removal
  • Groundwater remediation
  • Pre-treatment for RO/NF and membrane system
  • Pre-treatment for UV sterilizers
  • Filtration of gray, river or surface water
  • Tertiary treatment for waste water
  • Cooling tower and heat exchanger
  • Water features (fountains, etc.)
  • Industrial process water
  • Storm water
  • Irrigation water
  • Swimming pool water
  • Potable (drinking) water
  • Hotels and resorts
  • Beverage and food processing