Water Disinfectants and Oxidants
150 years ago when chlorine was first introduced as a water disinfectant, it was the only choice for treating drinking water.
Today there are many more options available for disinfecting water: ozone, hydrogen peroxide, chlorine dioxide, potassium monoperoxysulfate (KMPS) - each of these chemicals is a disinfectant of a different strength, suitable for different applications. They are all effective for water disinfection, and avoid some of the negatives/complications associated with the use of chlorine.
Oxidants are water additives that remove organic and inorganic components in water and wastewater by a chemical process called oxidation. Ozone, hydrogen peroxide, chlorine dioxide, chlorine, potassium permanganate, and potassium monoperoxysulphate (KMPS) are well known and widely used oxidants. UV radiation also triggers oxidation by direct photolysis of molecules. One of the strongest oxidants is formed during UV light dissociation of hydrogen peroxide. This reaction produces hydroxyl radicals, the strongest known oxidant in water treatment.
Chlorine dioxide (ClO2) has quite different properties than chlorine (Cl2). Chlorine dioxide is used as an advanced disinfectant for water and waste water treatment, as well as for disinfection of swimming pools. Unlike chlorine, it does not produce carcinogenic chlorinated organic compounds as a by-product of the disinfection process. For drinking water applications, chlorine dioxide technology has operational advantages over UV disinfection and standard chlorination, while operating at a comparable cost level. Chlorine dioxide has a long lasting disinfection effect through the residual concentration – something that neither chlorine, ozone, nor UV can provide.
PowerOxide™ kit is a powder for production of chlorine dioxide. Although the preparation of these concentrated chlorine dioxide solutions is less controllable than with the use of a chlorine dioxide generator, this method is often used when the capital investment in a generator system is not feasible, or when only single batches of chlorine dioxide are needed. PowerOxideTM components are ANSI60 certified for application in drinking water.
KMPS, potassium monoperoxysulfate (the “K” comes from “kalium”, the Latin word for potassium) in its stable form is a triple salt and a highly active oxidant. KMPS powder has a wide range of applications from shock oxidation/disinfection of drinking water and waste water lagoons prior to discharge, to super-disinfection of swimming pools, and rapid sanitation of water reservoirs (dugouts) for small communities. KMPS can be used together with sodium or calcium hypochlorite. KMPS is ANSI60 certified for application in drinking water.
Hydrogen peroxide (perhaps best known for its use in hair bleach) is used for water treatment as a very strong oxidant and as a slowly acting but strong disinfectant. The oxidation potential of hydrogen peroxide even exceeds that of potassium permanganate. It is most beneficial for oxidizing organic matter in raw water, enabling its easy removal through flocculation. Hydrogen peroxide can be used in treatment processes together with chlorine dioxide (but not with chlorine or hypochlorite).
Sodium Hypochlorite (Liquid Chlorine, Bleach)
Sodium hypochlorite is a chemical compound with the formula NaClO. It is usually called bleach, or liquid chlorine. The disinfection compound in the sodium hypochlorite is hypochlorous acid. Hypochlorous acid (HOCl or HClO) is an acid that is formed when chlorine gas dissolves in water. The hypochlorous acid can not be isolated from sodium hypochlorite solution, because it exists in equilibrium with its precursors. This equilibrium depends on numerous factors. One of the most important factors is pH. The disinfection efficiency of sodium hypochlorite depends on pH of water. Acceptable pH range for efficient disinfection is 6.8 – 7.5. Hypochlorous acid reacts with organic compounds and forms THMs (trihalomethanes).
Hypochlorous acid reacts with ammonia and forms chloramines, which are used as week secondary disinfectant. There are different types of chloramines. For water disinfection are used only monochloramines, which are formed in the pH range of 7.5 – 9.0. The most acceptable pH for water chloramination is 8.2 – 8.3.
Stabilized Sulphur Dioxide
Stabilized Sulphur Dioxide (also referred to as bisulfite bleach, sodium hydrogen sulfite or sodium bifulfite) is one of the few reducing disinfectants. It is a colourless solution with the distinct smell of sulfur dioxide. Bisulfate bleach is commonly used to reduce residual chlorine in chlorinated drinking water and waste water prior to discharge. It can also be used to prevent oxidative corrosion.
Please visit Osorno Store if you would like to purchase Stabilized Sulphur Dioxide Solution.
Ozone (O3) is a chemical produced when oxygen (O2) is exposed to UV light. Ozone is a powerful oxidant and is used in water and air treatment applications. Because ozone decays quickly, it cannot be manufactured and transported like other industrial gases. Osorno installs ozone generators for water and air treatment applications.