Mankind, in its pursuit of scientific and technological advancement, has exacted a terrible toll on the planet. Add a rapidly increasing global population and a fast depleting ozone layer to the pollution equation, and one starts to feel extremely sorry for Mother Nature. One of the direst consequences of such rampant pollution is a lack of clean, usable water.
The Methods Employed
Water filters were introduced to remove such impurities from water through various methods to make it usable for a variety of purposes, such as drinking, agricultural use, swimming pools etc. Water can be filtered by using a physical barrier or through biological and/or chemical processes. The more popular methods include sieving, ion exchanges and adsorption.
The Filters Used
There are several different types of water filters available. They differ according to the processes they employ for filtration. The most common types of water filters include: sand filter, cloth filters, screen filters, slow sand filter beds, media filters, rapid sand filter beds, disk filters and point-of-use filters.
The point-of-use filters include a sub-set of filters which normally we called drinking water system, such as: granular-activated carbon (GAC) filters, microporous ceramic filters, microfiltration and ultrafiltration membranes, carbon block resin (CBR), and metallic alloy filters.
Portable water filters are also available, and these can come in extremely handy. The military makes extensive use of them, while they come in handy for humanitarian aid organizations and hikers as well. These filters help combat disease-causing bacteria, microbial cysts and protozoa, and are usually light-weight and easy to carry around.
All the Certifications
Since water filters serve such a crucial purpose, it is only natural that they should be governed by a few rules and regulations and certifications. The American National Standards Institute has accredited three organizations to use the ANSI/NSF standards when certifying products. These standards are issued for both health and aesthetic concerns, and require verification of certain measures, such as the structural integrity of the product, the materials used, the contaminant reduction performance claims, and an overall evaluation of the unit.
The three accredit organizations, which certify compliance with the ANSI/NSF and the Environmental Protection Agency (EPA) standards, are:
NSF International: The basic purpose of the NSF Water Treatment Device Certification Program is to ensure that the requirements of the national standards are met, and to reassure the customers of such compliance. The production facilities are audited without any warnings and the products are tested extensively in order to accomplish this purpose.
Underwriters Laboratories: This is an independent organization that tests the aesthetic concerns, materials safety, structural integrity, and the contaminant reduction of water filter systems and certifies their compliance with the regulatory standards.
Water Quality Association: This association works similarly to the Underwriters Laboratories, except that it awards a Gold Seal to the water filters that meet the EPA and the ANSI/NSF standards.
With the availability of clean, usable water declining rapidly, the need for water filters in the various aspects of life – such as drinking, hygiene, irrigation – has increased and they have become nigh indispensable.