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Water Treatment Systems
Water treatment systems purify the raw water supply. They remove contaminants and impurities that can be harmful to the human body and damage the natural water cycle when they are returned back to environmental pathways.
Water treatment systems use several technologies, each designed to target specific contaminants. Some of the more common include: coagulation to cause fine particles to clump together and be skimmed or drained away, filtration for removing large sediment and chemicals and Ion exchange (IX) for chemical removal such as lime softening.
Activated Carbon Filters
Activated carbon filters work by using a process called adsorption, which allows for contaminants to become trapped on the surface of activated carbon. The contaminant molecules can then be removed by the filter, leaving you with filtered water that is safe to drink.
Carbon filters work to eliminate contaminants like chlorine, phenols, chloride, herbicides, pesticides, and VOCs (volatile organic compounds). They can also remove bad tastes and odors from water. They work to remove these contaminants from your water before they can be ingested, breathed in, or absorbed through the skin while bathing.
The pore structure of the activated carbon is what determines which contaminants it will be able to trap. To create the pore structure, the carbon is heated in the absence of oxygen at high temperatures and then “activated”. This process transforms the atoms in the carbon into millions of tiny pores that can trap large molecules.
Generally, there are two types of carbon used in water filters: powdered activated carbon (PAC) and extruded activated carbon. PAC contains incredibly fine particles made up of crushed or ground carbon, and is often added directly to other water treatment processes such as rapid mix basins and clarifiers.
Extruded carbon has a larger pore size than PAC and is often used in point of use home filters, such as refrigerator water filters, faucet water filters, or carbon block water filters. It is highly effective at removing organics and chlorine, as well as reducing VOCs. It can also be effective in removing chloramines and trihalomethanes from water.
Mechanical Filters
Biological and chemical water treatment systems need the help of mechanical filters to remove particulates from the system. While these filtration methods are effective at targeting specific types of contaminants, they cannot tackle the wide range of sediments that can enter commercial water treatment systems water systems. These include the dirt and sand commonly found in pipes from leaking or cracked lines, as well as the chemicals introduced by a variety of business practices.
These particles can be incredibly small and hard to target with a standard mesh or sponge, which is why mechanical filters use a series of progressively smaller sieves. These filters can be made of sand, silt, clay or other screening materials and are typically made to be reusable for ease of maintenance. These filters also work to reduce turbidity, intercept organic matter, chlorination smell and other impurities from water.
These filters are often found in a variety of forms including bag or cartridge units mounted on the end of a pipe, hang-on-the-back (HOB) systems and tank units that treat an entire building’s water supply. They can be used alone or in conjunction with a number of other filtration solutions for a comprehensive, complementary treatment process. Typically, these filters are cleaned with chemicals that dissolve impurities and help the filter to remain effective for longer periods of time between cleanings.
Reverse Osmosis
Reverse Osmosis (RO) is a highly effective way to get water clean on a molecular level. The process uses a semi-permeable membrane that separates pure water molecules from other molecules and particles such as chlorine, dirt, salt and microorganisms. Water that passes through the membrane leaves behind a stream of reject water (often called “concentrate”). This system is ideal for those who live in well-water areas where contaminants from pesticides on nearby farms, animal waste, industrial pollution and other environmental sources can contaminate groundwater supplies.
Reverse osmosis systems usually include four stages of filtration: a sediment filter, a pre-carbon block, an RO membrane and a carbon post filter. The first step, the sediment filter, removes large particulate such as sand, rust and clay to prevent clogging of subsequent filters. The second, the pre-carbon filter, binds with positively charged ions to prevent chemical compounds, like chlorine and chloramines from passing through to the membrane.
The third, the reverse osmosis membrane, removes dissolved molecules that are larger than water, such as sodium and high levels of lead. It also eliminates bacterial contamination, microorganisms and volatile organic compounds.
The fourth, a carbon post filter, eliminates any remaining unwanted flavors and odors and polishes the water for drinking. Some point-of-use RO systems use a fifth stage of ultraviolet sterilization water treatment systems supplier to ensure the safest possible water for cooking, drinking and bathing.
Whole House Filtration
Unlike point-of-use filters that are placed at individual water outlets, whole house filters are hooked up directly to your home’s main water line. This ensures every faucet, showerhead, toilet and household appliance receives filtered water. They also reduce mineral build-up and clogging that can reduce the lifespan of pipes and water-using appliances.
While advanced whole-house systems can filter out potential hazards like volatile organic compounds, pesticides and heavy metals, they’re often expensive—and can be overkill for most households. A simpler option is a whole-house water filtration system that combines carbon and sediment filtration to remove chlorine taste and odor, as well as sand, silt, clay and other particles.
The most affordable options feature a non-backwashing or upflow design that uses mechanical filtration to keep the filter tower clean and remove contaminants. These systems typically use a pre-filter to remove dirt, soil and rust flecks from the water, then a carbon filter that absorbs harmful chemicals, minerals and bacteria, then a sediment filter that traps unwanted particulates.
Other more comprehensive whole-house filters are backed by either an activated carbon or reverse osmosis treatment process that eliminates many types of contaminants, including arsenic, fluoride, chlorine, heavy metals, herbicides and other toxins. Activated carbon systems filter the water by adsorption, with the carbon material having a large surface area to trap and reduce contaminants as it passes through the filter. A reverse osmosis system filters the water through a multistage filtration process that can include water softening, an active carbon filter and an RO membrane.