Applications of (KDF) Filter Media in Water Treatment

KDF (Kinetic Fiber Deposition) media are widely used in pretreatment, primary treatment, and wastewater treatment equipment. They are often used in conjunction with activated carbon granular filters, carbon blocks, or in-tube filters, but can also be used alone.

Using KDF media for water pretreatment is a simple and low-cost method. For microfiltration, ultrafiltration, reverse osmosis membranes, ion exchange resins, and granular activated carbon, KDF media can protect these expensive and fragile water treatment components from chlorine, microorganisms, and scaling. Furthermore, KDF media can remove up to 98% of heavy metals such as Pb, Cd, Ce, Ag, Ar, Al, Se, Cu, and Hg. Additionally, the redox reactions that occur on KDF media can reduce carbonates, nitrates, and sulfates in water.

The main problem affecting the efficiency of membrane separation processes is the deposition of various contaminants on the membrane surface, causing pore blockage—this is an indisputable fact. Compared to microfiltration, ultrafiltration, reverse osmosis membranes, ion exchange resins, and granular activated carbon, KDF media offers numerous advantages in improving water treatment efficiency and maintaining high efficiency, while consuming less.

(1) Removal of Residual Chlorine from Municipal Drinking Water

KDF media is increasingly being used to replace or in conjunction with activated carbon filters to remove residual chlorine from municipal tap water (up to 99%). Its main advantage is its long service life. KDF media pretreatment extends the lifespan of granular activated carbon and protects the activated carbon bed from bacterial contamination. It increases the carbon's cleaning power by up to 15 times, and KDF enables the use of smaller carbon filters, thus reducing operating costs.

(2) Protection of Reverse Osmosis Units

Reverse osmosis membranes are easily corroded by chlorine. KDF media can replace activated carbon treatment to protect reverse osmosis (RO) units from chlorine and bacterial contamination. Activated carbon filters can also effectively remove residual chlorine, but because activated carbon quickly becomes saturated in high-chlorine water, the concentration of chlorine in the water must be strictly controlled during operation. Furthermore, activated carbon filter beds are prone to bacterial growth. KDF treatment media has a high chlorine removal rate. It also inhibits microbial growth, thus providing stable and long-term protection for reverse osmosis membranes.

(3) Inhibiting the growth of bacteria and algae in cooling water and reducing scaling

Water in cooling towers and water-cooled heat exchangers is often heated and exposed to air—thus becoming an excellent breeding ground for bacteria and algae (e.g., Legionella can be obtained from cooling towers). Traditional chemical methods control the growth of algae and bacteria in cooling towers by adding chemicals, which is expensive and results in high subsequent wastewater treatment costs. KDF treatment media treats cooling water at a low cost, effectively controls the growth of algae and bacteria, and does not use environmentally harmful chemicals. In addition, water treated with KDF media reduces the formation of hard scale. (4) KDF Treatment Media and Other Water Purification Systems

KDF media can control bacteria, algae, and their reproduction within granular activated carbon layers or activated carbon filter cartridges. When activated carbon is used in conjunction with KDF treatment media, the ability of activated carbon to remove organic impurities and residual chlorine is enhanced.

KDF treatment media can also replace silver-impregnated activated carbon, thereby reducing costs and avoiding the potential dangers caused by the toxicity of silver in silver-impregnated activated carbon.

(5) Removal of Harmful Heavy Metals and Other Soluble Heavy Metal Ions

KDF media can be used alone to remove harmful heavy metals such as lead, mercury, and arsenic from water to meet drinking water requirements. For example, in the 1994 issue 4 of the American magazine *Water Industry*, when the influent arsenic content was 5 mg/L, the arsenic content in the water after KDF filtration was reduced to 0.01 mg/L, achieving a removal rate of 99.7%. When using KDF for arsenic removal, no reagents are required, and the equipment is relatively simple, requiring only one KDF filter. The treatment process is also very rapid, with a filtration speed three times that of mechanical filters using quartz sand, thus requiring less space.

Other advantages of KDF: The long lifespan of KDF treatment media. All water treatment media have a limited lifespan. Silica sand (SiO2) is undoubtedly the longest-lasting filter media, followed by KDF. There are two situations that shorten the lifespan of KDF, each with a long duration. The first is when the residual chlorine content in the water is much higher than the dissolved zinc content. Municipal tap water with a residual chlorine concentration of 0.55 ppm will only produce 0.25 ppm of zinc after passing through KDF. Even after removing 10 ppm of chlorine, the zinc content will not exceed the standard. The second type is the physical degradation of KDF, such as corrosion, friction, or wear. However, physical effects have a minimal impact on the lifespan of KDF, conservatively estimated to be over 10 years.

KDF, a natural, non-toxic, high-purity copper-zinc alloy, provides high-quality domestic water. It reduces bacteria, heavy metals, chlorine, and other harmful components in drinking water and other household water, making the effects of chlorine invisible to users. This results in reduced flaky skin, rough hair, and algae in bathtubs and showerheads, leading to better-tasting water with fewer odors.

KDF is already widely used in the international water treatment industry. It is foreseeable that as domestic companies gradually understand KDF, its application in the domestic water treatment industry will become even more widespread.