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 in water and waste water treatment processes, and in 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™ is an almost odourless powder. Stir a package of PowerOxide A with a package of PowerOxide B into water, and almost instantly a strong solution of chlorine dioxide is produced – one of the most powerful disinfectants available. 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.
Hydrogen peroxide (perhaps best known for its use in hair bleach) is useful in 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).
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.
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 has a wide range of applications from shock oxidation/disinfection of 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.
Bisulfite bleach (also referred to as 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.
DisOx™ is a multi-purpose disinfectant with a wide spectrum of activity against viruses, fungi, and bacteria. It contains potassium monopersulfate (KMPS) as the main ingredient, sodium dodecylbenzenesulfonate (a powerful surfactant), and an acid/hydrogencarbonate for foam generation. DisOx™ is typically used for cleaning up potentially infectious spills, and disinfecting surfaces and soaking equipment. The solution is used in hospitals, laboratories, nursing homes, funeral homes, dental and veterinary facilities, animal husbandry operations, and anywhere else pathogen control is required.