Resin and Media Supplies

Anthracite (filter coal)

Although its potential for water treatment has been recognized since ancient times, anthracite coal was not used for this purpose until the beginning of the 20th century. Crushed Anthracite makes an excellent medium density filtration media. Clack Anthracite is mined from the finest Pennsylvania coal. It is specifically selected for water treatment, and during its production goes through several sizing inspections. Representative samples are randomly chosen for a complete laboratory quality control analysis for effective size, uniformity coefficient, specific gravity, acid solubility and hardness. Because of its angular shape, some of the sediment penetrates deeper into the bed. When compared to equivalent filter sands, this means longer filter runs and less head loss. Backwash rates are also reduced. Because of its unique density, Clack Anthracite can be used in multi-media filters. At 50 lbs/ft³, it will hydraulically classify and remain above heavier media such as Filter Sand or Manganese Greensand, providing a prefiltration layer.

Birm (Iron/ Manganese reduction Media)

Birm® is an efficient and economical media for the reduction of dissolved iron and manganese compounds from raw water supplies. It may be used in either gravity fed or pressurized water treatment systems. Birm acts as an insoluble catalyst to enhance the reaction between dissolved
oxygen (D.O.) and the iron compounds. In ground waters the dissolved iron is usually in the ferrous bicarbonate state due to the excess of free carbon dioxide and is not filterable. Birm, acting as a catalyst between the oxygen and the soluble iron compounds, enhances the
oxidation reaction of Fe++ to Fe+++ and produces ferric hydroxide which precipitates and may be easily filtered. The physical characteristics of Birm provide an excellent filter media which is easily cleaned by backwashing to remove the precipitant. Birm is not consumed in the iron
removal operation and therefore offers a tremendous economic advantage over many other iron removal methods.

Calcite (pH Correction)

Calcite is a naturally occurring calcium carbonate media. One of the advantages of Calcite is its self-limiting property. When properly applied, it corrects pH only enough to reach a non-corrosive equilibrium. It does not overcorrect under normal conditions. Upon contact with Calcite, acidic
waters slowly dissolve the calcium carbonate to raise the pH which reduces the potential leaching of copper, lead and other metals found in typical plumbing systems. Periodic backwashing will prevent packing, reclassify the bed and maintain high service rates. Depending on pH, water chemistry and service flow, the Calcite bed will have to be periodically replenished as the Calcite is depleted. As the Calcite’s calcium carbonate neutralizes the water, it will increase hardness and a softener may become necessary after the neutralizing filter. Calcite can be effectively combined with Clack Corosex to combine the high flow neutralization properties of Corosex, along with the slower reacting low flow properties of Calcite, increasing the ability to correct low pH.

Filter Ag (light weight filter media)

Clack Filter-Ag® has many outstanding advantages over the more common granular filter medias used for suspended solids reduction. Its fractured edges and irregular surface provides a high surface area and complex flow path for efficient removal of suspended matter throughout the filter bed, typically reducing suspended solids down to the 20-40 micron range. Filter-Ag’s larger particle size creates less pressure loss through the filter and allows deeper sediment penetration into the bed for higher sediment loading and longer filter runs. The large and irregular shape prevents the screening and caking of sediment in the top several inches of the filter bed as happens in the
typical sand filter, thus preventing a rapid buildup of headloss and blinding problems.Filter-Ag’s light weight means lower backwash rates and better bed expansion to release trapped sediment and rinse the filter media during the backwash cycle. Filter Ag Plus Cack Filter-Ag Plus is a unique natural ore called clinoptilolite that has many outstanding advantages over common granular filter sands and multimedia used for suspended solids reduction. Viewed under an electron scanning microscope, the granules reveal an angular shape, rough surface
and microporous void spaces as small as 3 microns. This creates a surface area over 100 times greater than silica sand. The angularity of the granules and the tapered internal pore spaces allow for reduction of dirt, silt and organic matter suspended in water by bridging, straining and adhesion. The rough surface and internal porosity provide a high surface area for efficient reduction of suspended matter. Utilizing deep bed filtration can typically reduce suspended solids down to the 5 micron or less range. Filter-Ag Plus’ structure typically creates less pressure loss through the filter and allows deeper sediment penetration into the bed for higher sediment loading and longer filter runs. The deep bed filtration capacity of Filter-Ag Plus prevents a rapid buildup of head loss and blinding problems that are associated with typical sand filters.

Filter Ag Plus

Cack Filter-Ag Plus is a unique natural ore called clinoptilolite that has many outstanding advantages over common granular filter sands and multimedia used for suspended solids reduction. Viewed under an electron scanning microscope, the granules reveal an angular shape, rough surface and microporous void spaces as small as 3 microns. This creates a surface area over 100 times greater than silica sand. The angularity of the granules and the tapered internal pore spaces allow for reduction of dirt, silt and organic matter suspended in water by bridging, straining and adhesion. The rough surface and internal porosity provide a high surface area for efficient reduction of suspended matter. Utilizing deep bed filtration can typically reduce suspended solids down to the 5 micron or less range. Filter-Ag Plus’ structure typically creates less pressure loss through the filter and allows deeper sediment penetration into the bed for higher sediment loading and longer filter runs. The deep bed filtration capacity of Filter-Ag Plus prevents a rapid buildup of head loss and blinding problems that are associated with typical sand filters. 

Filter Sands

Filter Sand and Gravel are naturally occurring, river washed, glacial deposit products. Their excellent chemical properties – high silica content and low soluble calcium, magnesium and iron compounds -. Precision sizing and uniform grading to close limits meet the rigid specifications of
professional engineers throughout the world. . These products have been specified and used nationally and internationally because of their high quality, desirable chemical properties, colour, and wide range of precision sizing. Processing and regular analysis of production are supervised by registered professional engineers. Clack Filter Sand is graded specifically for water filtration plants. It can be used in municipal, industrial or residential applications for sediment filtration. Clack Uncrushed Gravel has a highly spherical shape that promotes good flow and even distribution in support beds. Gravel is low in soluble impurities and it will maintain the quality of the treated water, especially
in softeners. Three-inch layers are recommended in graded support beds.

Water Softening Resin

In this application, ion-exchange resins are used to replace the magnesium and calcium ions found in hard water with sodium ions. When the resin is fresh, it contains sodium ions at its active sites. When in contact with a solution containing magnesium and calcium ions (but a low concentration of sodium ions), the magnesium and calcium ions preferentially migrate out of solution to the active sites on the resin, being replaced in solution by sodium ions. This process reaches equilibrium with a much lower concentration of magnesium and calcium ions in solution than was started with.

Idealised image of water-softening process, involving replacement of calcium ions in water with sodium ions donated by a cation-exchange resin

The resin can be recharged by washing it with a solution containing a high concentration of sodium ions (e.g. it has large amounts of common salt (NaCl) dissolved in it). The calcium and magnesium ions migrate from the resin, being replaced by sodium ions from the solution until a new equilibrium is reached. The salt is used to recharge an ion-exchange resin, which itself is used to soften the water.

Types of resins

Most typical ion-exchange resins are based on crosslinked polystyrene. The actual ion-exchanging sites are introduced after polymerisation. Additionally, in the case of polystyrene, crosslinking is introduced by copolymerisation of styrene and a few percent of divinylbenzene. Crosslinking decreases ion-exchange capacity of the resin and prolongs the time needed to accomplish the ion-exchange processes but improves the robustness of the resin. Particle size also influences the resin parameters; smaller particles have larger outer surface, but cause larger head loss in the column processes.[2]

Besides being made as bead-shaped materials, ion-exchange resins are also produced as membranes. These ion-exchange membranes, which are made of highly cross-linked ion-exchange resins that allow passage of ions, but not of water, are used for electrodialysis.

Four main types of ion-exchange resins differ in their functional groups:

• strongly acidic, typically featuring sulfonic acid groups, e.g. sodium polystyrene sulfonate or polyAMPS,
• strongly basic, typically featuring quaternary amino groups, for example, trimethylammonium groups, e.g. polyAPTAC),
• weakly acidic, typically featuring carboxylic acid groups,
• weakly basic, typically featuring primary, secondary, and/or tertiary amino groups, e.g. polyethylene amine.

Specialised ion-exchange resins are also known such as chelating resins (iminodiacetic acid, thiourea-based resins, and many others).

Anion resins and cation resins are the two most common resins used in the ion-exchange process. While anion resins attract negatively charged ions, cation resins attract positively charged ions.

Anion resins

Anion resins may be either strongly or weakly basic. Strongly basic anion resins maintain their positive charge across a wide pH range, whereas weakly basic anion resins are neutralized at higher pH levels.[3] Weakly basic resins do not maintain their charge at a high pH because they undergo deprotonation.[3] They do, however, offer excellent mechanical and chemical stability. This, combined with a high rate of ion exchange, make weakly base anion resins well suited for the organic salts.

For anion resins, regeneration typically involves treatment of the resin with a strongly basic solution, e.g. aqueous sodium hydroxide. During regeneration, the regenerant chemical is passed through the resin, and trapped negative ions are flushed out, renewing the resin exchange capacity.

Cation-exchange resin

The cation exchange method removes the hardness of water but induces acidity in it, which is further removed in the next stage of treatment of water by passing this acidic water through an anion exchange process. Formula: R−H acidic