• sand
  • gravel
  • carbon
  • manganese-dioxide
  • anthracite
  • garnet-sand
  • support-garnet

Media Selection

Media Selection

Media selection and its placement are two of the most important aspects of any filter refurbishment project as these directly affect the resulting efficiency and quality of output.

Treatment plant custodians should consider all aspects of the work as short term cost savings can lead to an overall increase in life cycle costs where compromises in either filter media quality or the choice of contractors are made.

The choice of filter media and support layers is dependant on the required filtration rate, the water being treated and the use for the resulting filtered water. Other factors affecting the media choice include the ambient temperature and the local environment which can, seasonally, change the treatment water significantly as to warrant additional filter media to be able to handle changes.

  • Sand - The standard filter medium for water treatment normally available from suppliers in various grades depending on application e.g. slow sand filter, rapid gravity filters. Size defined as either a mesh size or, more commonly, as a BS ( British Standard ) spec e.g. BS16/30

  • Gravel - Various sizes of gravel are available . Support gravel used as the first layer in filter bed and should be installed and levelled off prior to any other media placement. During the backwash cycle this layer of support media should not be disturbed ( this is why the selection of grade size is very important ) .

  • Carbon - Relatively expensive filter media used , primarily , for taste and odour removal with other uses such as dechlorination and organics removal. Manufactured from coconut shell and coal based carbons using a thermal process it contains thousands of pores. It is these pores which trap organics and chlorine.

  • Manganese Dioxide - Principally found mixed with normal filter sand to remove both iron and manganese from potable water where there is an increased concentration of those elements in the treatment liquor. The use of manganese dioxide will normally reduce the concentration of Manganese and Iron in water from 0.5mg/l and 3mg/l to 0.02mg/l and 0.05mg/l respectively ( given the correct conditions of alkalinity and pH ).

  • Anthracite - Typically found in dual media filters it is used to increase filter runs due to its relative bulk density and coarseness which makes it suitable to trap larger particulates at the top of the filter bed.

  • Garnet Sand - Normally used in multimedia filter applications to trap smaller particulates where normal filter sands do not provide the required inter-grain sizes. Its specific gravity and small size will ensure that it is found closest to the filter nozzles which must be chosen to prevent media migration.

Whether it's the delivery of thousands of tonnes for a major CDM contract or the upgrade of a rural water treatment works in the north of Scotland,Filtec Water Services. Filtec delivers on time every time.

Media can be placed as part of our normal service offerings. Read More »