Activated Carbon Filters


Many water sources in the UK contain free chlorine to reduce the level of bacteria present in the water; however this can add taste and odour as well as a strong oxidant. This can potentially attack water treatment medias such as ion exchange resin and reverse osmosis membranes. For these reasons, it is sometimes beneficial to remove the free chlorine. Surface waters may similarly contain high levels of organics which can add an unpleasant colour to water and can also foul reverse osmosis membranes.


Activated Carbon (AC) is a specialised water filter media, primarily used for the reduction of chlorine and related contaminants from mains water supplies. Activated Carbon is most often a coconut shell product treated with steam and pressure to create a media with a large number of porous sites in, and over, the entire surface; these sites being positively charged. As water passes across the carbon media, the contaminants are held within deep fissures on the surface, or are altered by the catalytic action of the media; backwashing subsequently cleaning the filter bed.


AC performance will vary depending on contact time; with extended contact time often being required for effective colouration and organic removal.

Iron and Manganese Filters


Along the side of water hardness, the presence of Iron and Manganese in water is probably the most common water concern. Iron and manganese, in excess of the suggested maximum contaminant levels (MCL) may result in the discolouration of water causing staining of equipment and final product; it can also give a metallic taste to water or to manufactured foodstuffs.


Filtration of Iron and Manganese is typically carried out using a Manganese Dioxide based media (a catalytic media converting dissolved iron and manganese to an insoluble, and subsequently, readily filtered, substance).

In some instances a mixture of sand and Manganese Dioxide can be used but more often a proprietary product such as Filox R or Burgess Iron Removal Media (BIRM) is used, offering operational advantage to the procedure.

Multi Media Filter 


Multi Media Filter is a term usually used to refer to a filter containing media layers of anthracite, graded sand and a lower gravel support bed; such filters are used primarily for removal of suspended solids (particulates sizes as low as 10-20 microns) and turbidity.

Periodic backwashing of the filter media carries away trapped solids to drain. Backwash initiation of small filters is typically carried out on a timed basis whilst larger filters sometimes employ measurement of differential pressure across the filter bed to initiate backwashing, or to act as a back-up to timed initiation.

pH Correction Filter 


Many borehole water or spring supplies have a pH of less than 7. These waters are considered to be acidic and potentially damaging causing staining and corrosion.


Treatment, by means of a pH correction filter, involves the use of a neutralising media, generally composed of crushed and processed limestone. This media dissolves into the water as it passes through the filter and the natural alkalinity of the filter media raises the pH. It is important to note however that due to the calcium level within the filtration media, the hardness of the water is also affected and may be expected to rise by around 50ppm. In such instances additional treatment by water softener may also be required.

Cartridge Filters 


Puretech Ltd can provide a range of Cartridge Filters to suit all applications. Our range, predominantly manufactured in the UK, includes:


  • Depth Filter Cartridges

  • Pleated and Membrane Filter Cartridges

  • Activated Carbon Filters Cartridge


Depth Filters provide an inexpensive solution to filtration requirements particularly where the filtrate bears a high particulate loading. The graded porous media allows a high level of dirt trapping and retention whilst the extruded core of the filter offers high collapse strength, the sum providing long filter service life and lower consumable cost.


Available as nominal or absolute rated filters this range offers removal of particulate from 1 - 200 microsiemens; filter lengths from 4 7/8" - 40" and filter media constructed of polypropylene, nylon, cotton fibres and glass fibre.

Filters can be supplied in standard format or as large diameter to suit your specific application and requirement.


Pleated and Membrane Filters offer a wider range of suitability, a number of options being available from the nominally rated Economy Polyester Pleated Range through to the absolute rated Polyethylene Pleated Range providing filtration at >99.98% removal (at the stated rating) temperature.


  • Our Economy Range is designed to maximise dirt holding capacity and minimise pressure drop at high flow rates. The polyester media is bacteria and chemical resistant and has an extremely high wet strength offering an ideal solution for pre and final filtration of a wide variety of processes, giving long service life at minimal cost.


  • Our Premier Range comprises absolute rated pleated cartridges constructed using technically advanced, carefully specified, high quality filter media. From general purpose use to fine particulate removal, pre-filtration duties and microbial reduction in pure water systems, these filters, batch numbered to enable full traceability, offer a cost effective solution across a broad range of applications.


  • Our Ultra Range, manufactured under clean environmental conditions, provides the highest possible standard of quality assurance and performance. All products are fusion bonded into pure polypropylene hardware. The absence of any adhesives results in low extractables and simplifies the assessment of chemical compatibility.


Available in filter lengths from 97/8" to 40" and rated from 0.2 - 100 microsiemens filters can be supplied in standard format or as large diameter to suit your specific application and requirement.


Activated Carbon Filters - Many water sources in the UK contain free chlorine to reduce the level of bacteria present in the water however this can add taste and odour and as a strong oxidant, this can also attack water treatment medias such as ion exchange resin and reverse osmosis membranes. Activated carbon provides effective removal of such contaminants.


Our range of radial flow activated carbon filters available in lengths from 97/8" - 40" offer the benefit of a pre filtration layer (to intercept gels and large particle) and high quality extruded carbon providing long service life and superior absorption performance.


Bags Filters, Housings and Accessories 


Bag filtration is often employed in similar applications to cartridge filters; however major advantage can be achieved where high volume, high viscosity filtration is required. Additional benefits of bag filtration are:


  • The achievement of high flow rates in a filter housing just a fraction of the size of a cartridge vessel, thus reducing initial capital expenditure and space.

  • A reduced consumables cost pro-rata to the contaminants removed.

  • A vast range of filter bag capability (from 1 to 800 microns).

  • Simple and quick change-out, reducing expense and potential downtime.

When bag filtration is correctly specified it is can provide an exceptionally low cost solution.