Due to its unique density, 0.8 grs/cm3, anthracite can be used in multimedia filters. It is hydraulically adequate and will remain on top of other heavier media, such as sand or granite, creating another filtration layer. This yields to longer runs, lower pressure drop across the filter, no to mention the backwash frequency reduction, which translates into a huge water consumption reduction for this stage.
It's a high density and hardness granular filter media. It's commonly used as the finest filtration of a multi layer filter working down-flow. This configuration of bigger grains accommodated on top finer grains is accomplished using materials with different sizes and specific weight. Granite has a specific weight of 4.0 and forms the lowest layer of fine grains; its effective size of 0.3 mm can retain particles in a range of 10-20 microns.
TURBIDEX / FILTER-AG
A new filtration system, much more effective than previous ones, is the media Turbidex, a high surface, high porosity, alumino-silicate mineral that provides exceptional suspended solids removal.
Turbidez allows for filtration at levels below 5 micrones in particle size. These results are obtained, not only by physical separation, but also through electrostatic absorption, flocculation and Ion Exchange. As a result of the filtration trough Turbidex, water reaches a turbidity lower than 0,1 NTU.
One of the main advantages of the filter is that water requires no additional filtration to be used, as it occurs with regular multimedia filters, or sand filters, after which other filters are needed.
On the other hand, this technology reduces the chemical consumption and changing frequency of cartridges filters, on top of extending the time between chemical cleaning and life of membranes of equipments installed after the filter. Another advantage is the simplicity of working with a single media, instead of layers of different media, with different density, weight and packaging.
When designing the filter, it is important to take into account the backwash frequency, the flux (between 12 and 30 m/h), the bed height (approximately 1 m), the freeboard ( 0,3 - 0,5 m) and the pump capacity to operate both when filtering as when backwashing the bed.
For further information, please visit: www.turbidex.com
ADSORBSIA is a DOW development for the reduction of Arsenic and other heavy metals. The granular media made mostly of Titanium Dioxide is disposable and keeps the kinetic properties of its nanocrystalline structure, maintaining a physically stable structure. Studies in The United States have proven that ADSORBSIA presents kinetics ten times higher than regular media, made of Iron oxides.
One of the main advantages of the media is its robustness on removing arsenic while it's exposed to variable pH conditions. Even under these conditions, it consistently removes As, which is extremely important when there are seasonal changes on feed pH.
ADSORBSIA is a one-time use media, usually operated downflow. Periodical backwashes may be needed, with the single objective of expanding the bed, although the typical frequency is very low. Since the media is disposed after exhausted, no arsenic containing flows are generated, so no additional treatment is required. Due to its high affinity with arsenic, it is safe and easy to dispose off the media as landfill, since it´s a non hazardous waste.