How to Purify Water
Whether in the wilderness or your home, knowing how to purify water is vital for survival. Purification of water removes contaminants like toxins, bacteria and viruses.
The simplest way to purify water is to boil it for one minute. This will kill bacteria, viruses and parasites.
Many plants can also naturally purify and filter water. Some examples include fruit peels and the inner bark of Oregon Grape.
Pretreatment
Water pretreatment removes physical, chemical and biological contaminants from raw water to prevent the contamination of other processes or equipment. It also improves the organoleptic qualities of water such as taste, odor, color and hardness. Pretreatment is essential for industries because it protects equipment by reducing purification of water the concentration of chemical contaminants, thereby extending the life of pumps and filters. It also reduces the amount of energy needed for filtration, which saves money and reduces carbon emissions.
There are many different ways to pre-treat water, depending on the quality of the raw (source) water and the standards required for filtered water. For example, aeration is used to remove volatile chemicals such as benzene and trichloroethylene, dichloroethylene, perchloroethylene and methyl chloride (solvents used in dry-cleaning and industrial processes). It can also be used to eliminate odors and to raise the pH of the water. Carbon dioxide can also be removed from the water through aeration, which can cause bubbles or by adding lime.
Other common pretreatment techniques include fluoride removal (which is added to many public water supplies) and ozonation. It is important that these chemicals are well mixed with the source water before treatment to avoid short-circuiting and plugged pipes. Chemicals are typically fed to the water through dry chemical feeders and solution (metering) pumps. Your Aqua Clear field engineer can advise on optimal pretreatment chemistry to achieve the desired results for your application.
Filtration
Filtration is the separation of solid particles from a liquid using a material with pores that can only be occupied by fluid. The resulting clear liquid is known as the filtrate. Filtration is a very important step in water purification. It removes many of the bacteria, viruses and protozoans that are found in drinking water. This is also one of the reasons why public water supplies are typically treated by filtration.
Historically, people obtained clean water by scooping a hole in the sand of a muddy river and watching as clear water filtered through. Modern water purification processes are much more elaborate, but the basic idea remains the same. Particles in water can be either organic (algae, fungi and bacteria) or inorganic (clay and silt). Both types of particles contribute to turbidity and should be removed.
Most of the time, the most effective way to remove the inorganic particles is with a coagulation basin and metal salt coagulants (coagulants). The more common organic polymers are also sometimes used as coagulant aids or replacements for the metal salt coagulants.
Unfortunately, boiling water does not remove all the impurities and contaminants present in most drinking waters. That is purification of water manufacturer why chemical analysis is necessary to determine which kind of treatment, if any, is required. This can include a wide range of physical and chemical tests to determine if bacteria, viruses, heavy metals or other chemicals are present in the water supply.
Disinfection
Water must be disinfected to kill any pathogens present and prevent further contamination. Boiling is one of the easiest and safest methods of disinfection. Several minutes of a rolling boil will sterilize most bacteria and other organisms.
Other methods include filtration, sedimentation, ion exchange and distillation. All of these physical approaches utilize the phenomenon that solids have a lower boiling point than water. Filtration removes organic matter, sediment and turbidity by interposing a medium that retains the material while allowing water to pass through. Sedimentation and ion exchange are both based on the principle that mineral salts have different charged ions (cations and anions). Ion exchange raises water pH by using lime or soda ash to add positively charged cations to the water which then attach to an insoluble substance and are removed from the solution.
Disinfection uses chemical agents such as halogens to inactivate microorganisms and their cyst forms. However, the effectiveness of any disinfectant depends on the species, strain and condition of the test microorganisms. In addition, many raw water contaminants exert a demand for the disinfectant; they react with and consume it.
Bleach is a simple, inexpensive and effective emergency disinfectant that can be used to kill viruses, bacteria and protozoa (cyst stage). It is important to use household liquid bleach only as the product label directs. Other chemical treatments such as iodine or products sold in camping and military surplus stores should not be used.
Disposal
Water can be purified to a variety of levels for a variety of uses. The process involves removing unwanted particulate matter, pathogens and other contaminants. The main purpose of purification is to make the water safe for human consumption, but it can also be used for medical, industrial and chemical applications. The different processes of water purification include pretreatment, filtration and disinfection.
Physical approaches to purification involve the use of filters, sedimentation and distillation. Filtration is based on the separation of solids from fluids, using a medium that retains the solid particles while passing the liquid through it. Sedimentation uses gravity to remove sediment from a body of water, while distillation transforms a liquid into vapor before condensing it back into water.
Brine waste streams are concentrated salt solutions that occur naturally as seawater or deep ocean pools or as a byproduct of industrial production processes. The waste can contain a wide range of contaminants, depending on which industry it is produced by. To purify brine, it can undergo a number of processes, including ion exchange and reverse osmosis. When used properly, these systems reduce contaminates to levels that meet regulatory requirements for drinking water. They also eliminate the need for the addition of chemicals. The disposal of brine is important to ensure that it does not contaminate groundwater sources or surface waters.
