In 1893, the first full scale ozone system for drinking water was commissioned in the Netherlands. Today, more than 2,000 installations worldwide use ozone to treat potable water and its use is increasing rapidly due to rapid advancement in technology, decreasing capital equipment cost & maintenance costs, and the continuing discovery of new process applications . Applications of ozone for municipal water include the following:
Water is the one substance from which the earth can conceal nothing; it sucks out its innermost secrets and brings them to our very lips. — Jean GiraudouX (1882-1944)
The most common application of ozone is for primary disinfection. Ozone technology for potable water reduces the risk of dangerous disinfection byproducts such as trihalomethanes (THM). As one of the strongest oxidants on earth, ozone effectively destroys a broad spectrum of pathogens and microbes including all known viruses, bacteria, Giardia, Cryptosporidium and Amoebae.
Oxidation of Metals
Ozone is commonly used to oxidize heavy metals from water such as iron, arsenic (in the presence of iron) manganese, cadmium, chromium, copper, lead, and zinc. At a higher oxidation state, these metals form a less soluble oxides that are easy to separate by filtration. Unlike chlorine oxidation, ozone does not form a dangerous level of bromate when bromide is present in raw water.
Oxidation of Organics
Ozone is an effective, fast-acting oxidizer of organic compounds such as sulfate, hydrogen sulfide, algae, and synthetic organic compounds such as pesticides and solvents.
Odor, Taste, & Color Removal
For municipal distribution systems, the majority of customer complaints are related to taste and odor issues. Virtually all bottled water manufacturers incorporate ozone into their treatment train to produce the most desirable taste and clarity for their product.
Ozone is an efficient oxidizer of odor, taste and color-causing compounds. Color is linked to the presence of humic and fulvic acids that consume a large volume of chlorine and form halogenated volatile organic compounds; ozone reduces the formation of these compounds.
Oxidation of CEC’s
An issue of expanding public and political interest is the presence of constituents of emerging concern (CECs) in nearly all water sources. This term is used to include a broad range of unregulated chemical components found at trace levels.
These compounds include trace organic contaminants (TOrCs), personal care products (PPCPs), pharmaceuticals, endocrine disrupting compounds (EDCs) and microconstituents. The list of CECs is expanding further to include known disinfection byproducts, such as N-nitrosodimethylamine (NDMA).
Reducing and or eliminating CEC compounds with ozone / advanced oxidation processes is an effective method. Although ozone reacts preferentially with most compounds depending on their structure, it can also react with natural organic matter to for hydroxyl radicals and indirectly oxidize a greater number of constituents. Hormones are compounds that react well with ozone, as are most pharmaceuticals that have been tested.
Ozone is effective at oxidizing some of the most frequently detected CEC’s, such as carbamazepine (anti-epileptic drug), cotinine (nicotine metabolite), caffeine, and atrazine (pesticide).
Ozone Assisted Biological Treatment
Biological treatment processes rely on the metabolic activity of a diverse population of bacteria to degrade organic material in water. Most natural and organic compounds are biodegradable by microorganisms as part of their metabolism for energy and growth.
Ozone pretreatment can degrade inorganic compounds to structurally simpler molecules that can be consumed by microorganisms. Since ozone is an unstable molecule, it quickly converts to oxygen to aid biological activity, thus reduces backwashing requirements and increases media (GAC/Sand) life-span.
Advanced Oxidation Process (AOP)
Basic AOP processes where ozone is applied simultaneously with ultra-violet radiation (UV) or hydrogen peroxide, produce an aggressive hydroxyl radical that enhances the oxidation rate of contaminants.
AOP’s attack nearly all organic complexes and have a high potential to degrade contaminants that are not affected by ozone or sodium hypochlorite. Hydroxyl radicals have shown to effectively oxidize pharmaceuticals, personal care products and 1,4-dioxane.
Pureflow Ozone Division, in conjunction with our partners, possess the ability to pilot, design and manufacture state-of-the-art advanced oxidation process for the municipal water marketplace.