A filter is a device which removes impurities from water by means of physical barrier. Filters are used to treat water for irrigation, drinking water, aquariums, and swimming pools.
Reverse osmosis water filter
Reverse osmosis is a water treatment process whereby dissolved salts, such as sodium, chloride, calcium carbonate, and calcium sulfate may be separated from water by forcing the water through a semi-permeable membrane under high pressure. The water diffuses through the membrane and the dissolved salts remain behind on the surface of the membrane.
A water ionizer is an appliance that reportedly ionizes water, although it is not entirely clear what is meant by this claim. It is interesting to note that water, even pure water, in its liquid form naturally self-ionizes to 10-14 M, and that it is impossible to force water permanently into a higher state of ionization without the addition of other chemicals (for example, by creating an acidic or basic solution).
A water softener reduces the calcium or magnesium ion concentration in hard water. These "hardness ions" cause three major kinds of problems. The metal ions react with soaps and calcium sensitive detergents, hindering their ability to lather properly and forming an unsightly precipitate— the familiar scum or "bathtub ring". Presence of "hardness ions" also inhibits the cleaning effect of detergent formulations. More seriously, calcium and magnesium carbonates tend to adhere to the surfaces of pipes and heat exchanger surfaces. The resulting scale build-up can restrict water flow in pipes. In boilers, the deposits act as thermal insulation that impedes the flow of heat into the water; this not only reduces heating efficiency, but allows the metal to overheat which, in a pressurized system, can lead to failure. The presence of ions in an electrolyte can also lead to galvanic corrosion, in which one metal will preferentially corrode when in contact with another type of metal. The use of water softeners can aggravate this and cause sacrificial anodes in hot water heaters to corrode more quickly.
Water cooler and dispenser
A water cooler (more commonly denoted by the single word "watercooler") is a device that cools and dispenses water. For devices that cool air, by use of water evaporation, see evaporative cooler. They are generally broken up in two categories: bottle-less and bottled water coolers. Bottle-less water coolers are hooked up to the water supply, while bottled water coolers require delivery of water in large bottles from vendors.
Water Filter Replacement Cartridges
Recommended filter service life and change cycle
- Sediment Pre-Filter - Change every 3 - 6 months (more often in areas with very high turbidity in water).
- Carbon Pre-Filter - These filters should be changed every 6 - 12 months. This is necessary to help insure membrane life and water quality.
- R.O. Membrane - The R.O. membrane would be changed when rejection rate falls to 80%. The rejection rate should be tested every 6 to 12 months. The membrane can last up to 5 years depending on the water quality, the hardness of the water coming into the system and the frequency of filter changes. The only way to know when it is time to change the membrane is to know when the rejection rate of TDS falls below 80%. To do this you will need a TDS tester (total dissolved solids) This allows you to compare the amount of TDS in the incoming water vs. the drinking water. TDS testers are a basic tool in proper maintenance on any reverse osmosis system
- Carbon Post Filter - This filter needs to be changed every 6 - 12 months to insure quality water. Do not wait until taste is a problem.
All Reverse Osmosis systems require some periodic maintenance to insure you are getting the same water quality as when the system was new. There is no maintenance more important than timely filter changes. Filters need to be replaced at recommended intervals because they retain a considerable amount of debris and contaminants. Failure to change filters or use of lower quality filters, can reduce membrane life and water quality dramatically. DO NOT WAIT UNTIL YOUR WATER TASTES BAD TO REPLACE YOUR FILTERS. Remember - most contaminants don't have a foul taste except in extreme quantities
The complexity of water quality as a subject is reflected in the many types of measurements of water and Wastewater quality indicators. These measurements include (from simple and basic to more complex):
- Electrical conductivity
- Dissolved Oxygen
- Color of water
- Taste and odor (geosmin, 2-methylisoborneol (MIB), etc)
- Total suspended solids (TSS)
- Dissolved metals and salts (sodium, chloride, potassium, calcium, manganese, magnesium)
- Chemical oxygen demand (COD)
- Biochemical oxygen demand (BOD)
- Microorganisms such as fecal coliform bacteria (Escherichia coli), Cryptosporidium, and Giardia lamblia
- Nutrients, such as nitrogen and phosphorus
- Dissolved metals and metalloids (lead, Mercury (element),arsenic, etc.)
- Dissolved organics: Colored Dissolved Organic Matter (CDOM), Dissolved Organic Carbon (DOC)
- Heavy Metals
- Hormone analogs
Some of the simple measurements listed above can be made on-site (temperature, pH, dissolved oxygen, conductivity), in direct contact with the water source in question. More complex measurements that must be made in a lab setting require a water sample to be collected, preserved, and analyzed at another location. Making these complex measurements can be expensive.
Because direct measurements of water quality can be expensive, ongoing monitoring programs are typical conducted by government agencies. Individuals interested in monitoring water quality who cannot afford or manage lab scale analysis can also use biological indicators to get a general reading of water quality. Biological monitoring metrics have been developed in many places, and one widely used measure is the presence and abundance of members of the insect orders Ephemeroptera, Plecoptera and Trichoptera (EPT). EPT indexes will naturally vary from region to region, but generally, within a region, the greater the number of taxa from these orders, the better the water quality. A number of websites originating in the United States offer guidance on developing a monitoring program and identifying members of these and other aquatic insect orders.