To provide water that is safe for human consumption, there are a number of processes that the water treatment industry use.
Coagulation and flocculation are often the first steps in water treatment. Chemicals with a positive charge are added to the water. The positive charge of these chemicals neutralises the negative charge of dirt and other dissolved particles in the water. When this occurs, the particles bind with the chemicals and form larger particles, called floc. To separate the floc from the water, it is allowed to settle and fall to the bottom of the water during the sedimentation process. The clear water is then passed through various filtration compositions and sizes to remove any remaining dissolved particles. Finally, the water is disinfected with further chemicals, such as chlorine, to kill any bacteria and protect the water as it is piped to homes and businesses.
The chemicals used during the water treatment process pass through metering equipment in a dosing system. In the system, the solution is at its strongest and the chemicals are often corrosive and can be flammable. The plant room or dosing cabinet needs to be ventilated to prevent a harmful build-up of chemicals in the air around the equipment. Plant room and cabinets can be vented directly to the outside air or, more commonly, through an air filtration system. A filtration system is the more environmentally friendly option as it helps keep the air surrounding the water treatment site clear of harmful chemicals.
The corrosive nature of the air to be extracted means that standard metal fans would be adversely affected and not withstand the environment for long, therefore, fans made from polypropylene are needed in this application. Axair Fan’s ‘Storm’ range of polypropylene fans are best suited to this application as they are designed to perform in the corrosive air, providing a relatively low air flow rate against elevated system pressures. ATEX rated versions are also available on request for circumstances where the chemicals in use create the potential for explosions due to their flammable nature.
Axair Fans UK Limited have been associated with fan for various applications within the water treatment industry for many years and supply products to a number of industry leaders involved in the build and installation of chemical dosing equipment. A full range of accessories are available including weather protecting pedestals, energy efficient speed controllers to match fan performance to the application requirements, anti-vibration mounts and flexible connectors.
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