Reverse Osmosis Filtration Systems – The Pros and Cons
Reverse Osmosis Filtration Systems is extremely popular for use in water treatment plants. They remove large particulates and biological contaminants from water, which is a key requirement for effective public health and environmental protection. They can remove such pollutants as THMs (trihalomethanes), VOCs (volatile organic compounds), and pesticides. They also lower the mineral and pH content of water, removing the need for additional chemicals to adjust the taste and pH level of water. All of this allows you to use tap water without the expensive cost and waste of using RO or distillation to remove contaminants. In fact, many RO systems have a provision for the addition of a carbon filter at the point-of-entry to remove chlorine.
There are two main types of reverse osmosis filtration systems. The first is a semi-permeable membrane system that traps small particles in a thin film. The second type of system works by using a three-stage filtration process. These types of systems have different stages, which are based on the size, gravity, and size of the particle that needs to be trapped.
The first type of system works by forcing water through a semi-permeable membrane. This passes through several layers of micron sized porous materials, where the smaller pores on the surface of the membrane attracts larger dissolved solids, and the larger solids repel smaller dissolved solids. The larger solids can then pass through a resin bed, where they become separated from the larger suspended solids. The last process through the system removes the larger insoluble matter. The semi-permeable membrane can trap some naturally occurring contaminants, which can be beneficial, but most systems contain a balance of naturally occurring and synthetic chemicals that can remove some of the naturally occurring contaminants. The system also removes certain trace minerals from the tap water.
The other type of reverse osmosis filtration systems are either point of use filters or point of entry systems. Point of use filters attach directly to the faucet or showerhead, or to the counter or sink. They allow filtered water to be consumed directly, or they can be used as showerheads, to filter water before it enters the shower. Point of entry systems must be attached to the pipes that transport tap water into the home, typically in the basement or garage. This system requires more frequent maintenance because the water will not be flowing clean into the house at all times and will need to be replaced from time to time. It is cost effective over the long run, however, because it does not require any replacement of the filter material.
Some reverse osmosis filtration systems combine both stages of the filtering process. One membrane is placed over the contaminated water. As the water passes through the membrane, the contaminants are filtered. Then the remaining water is pushed through a second, larger membrane, leaving the contaminants behind, but the remaining liquid sanitized and filtered.
Since this is only one method of purifying tap water, there are a number of advantages and disadvantages of using reverse osmosis systems. First, it is slower to process than the natural process known as adsorption. This means that you will have to process more water, which could be expensive if you need it on a regular basis. Second, it does not remove any of the most common contaminants found in tap water. Third, it does not remove chemicals such as herbicides or pesticides. Fourth, it does not remove lead, copper, or mercury.
This post was written by a water treatment expert at Pure Blue H2O They offer whole home water solutions such as reverse osmosis systems, shower head filtration, filter replacements, and a variety of similar products. Their focus is to provide Americans with safe and clean water throughout the home.