Water dispenser Q&A
Water filtration technologies
Membrane filtration employs a thin layer of a material to retain specific particles or molecules. This method is employed for dissolved substances, filtering out particles of a certain size, and letting smaller particles pass through. In BRITA water dispensers, the membrane filters – included in the BRITA CLARITY Protect and CLARITY Safe X3 filter cartridges – are located at the dispenser water inlet and, as a second safeguard, directly upstream of the dispenser outlet tap. When you dispense water, the membrane removes bacteria, microbial cysts and other unwanted impurities that may come from the mains – right then and there. This final layer of protection guarantees water of outstanding quality and hygiene every time you use your dispenser.
Depending on the mineral composition of the local mains water, ion exchangers remove specific unwanted ions, e.g. calcium and magnesium, that could otherwise cause limescale deposits in equipment, including hot water dispensers such as BRITA VIVREAU Extra C-Tap. The ion-exchanger releases other ions into the water while it binds the unwanted ions on its surface. This technology is featured, for example, in the BRITA PURITY C Dispenser filter.
Activated carbon is a natural material of high microporosity, and with a huge internal surface area. It is therefore able to effectively absorb and bind substances. The carbon is often sourced from wood, peat, coal or coconut shells. BRITA activated carbon is made from coconut shells, as these are a renewable resource. Activated carbon filtration reduces organic substances in water, such as residues from pesticides or industrial dyes. It also reduces substances that could impact taste and aroma, such as chlorine and chlorine compounds, organic compounds and metabolic products from bacteria. Activated carbon is a key component in BRITA filters, and has a special role in cold water filtration in particular.
The first step in filtration is to remove particles and reduce turbidity. Particles in drinking water typically come from piping, and are in most cases not harmful to health. However, particles can cause blockages in e.g. water dispensers, leading to equipment downtime. During filtration, the filter fleece retains particles by acting as a sieve; particles are trapped on the surface of the filter, and within the fleece itself. All BRITA water filters combine particle filters with activated carbon, and some models include an ion exchanger.
Impurities targeted by filtration
Pharmaceutical and hormone residues, and their by-products, can enter the environment via waste water. They can then end up in mains water, though only in very small quantities. Water is often tested for naproxen, lindane and estrone, as these substances are particularly common.
Particles in water mainly come from deposits formed in piping. In chemical terms, they include a mixture of limescale, gypsum, silicates (sand), and substances from pipe corrosion (rust). Pressure surges or simply the normal flow of water can dislodge particles.
Metals are not usually found in mains water, but can be introduced via corroding pipes. Residential piping can be made of galvanised steel, copper, stainless steel, brass – and in rare cases, lead. Water stagnation in plumbing can raise the concentration of metals above specified thresholds.
During treatment, chlorine and chlorine compounds are added to water in the lowest quantities possible – ideally below the odour threshold. However, higher levels of chlorine may be needed for transmission over longer distances. Chlorine can also form compounds with organic substances, negatively affecting water’s taste and aroma.
Organic contaminants include diverse chemical compounds – from industrial substances, such as solvents (e.g. benzene), to residues from medicines and pesticides, to natural organic compounds. They enter mains water through emissions, for instance.
During the water cycle, rain absorbs CO2 in the air. It becomes slightly acidic and falls, dissolving minerals in the ground, e.g. calcium carbonate. This raises water’s carbonate hardness. However, too much mineral content in water can affect how beverages taste, and lead to limescale deposits in equipment.
Asbestos is a heat-resistant fibrous silicate mineral. It has been widely used e.g. as insulation, as an anti-corrosion coating and, in the past, as a building material. Asbestos fibres can enter water via piping, including asbestos-cement pipes (which were permissible in the past) and coated pipes.
Microplastics are, simply put, plastic fragments smaller than 5 mm. They can be found in mains water, and include primary microplastics, e.g. cosmetics, facial scrubs, and cleaning agents, as well as secondary microplastics, e.g. from the degradation of plastic products and car tires.
By definition, mains water is clean – but not sterile. It is treated to meet established microbiological limits. However, as water is transported via the mains system, germs (e.g. bacteria and cysts) can multiply. This is especially true of stagnant water.