Ozone: Its Properties and Industrial Uses
» Table of Contents
In the following pages is a brief summary of Ozone and its related uses. This information is intended to give the readers a general overview of Ozone. It is not to be used for engineering specific ozone treatment systems. Nutech 03 only guarantees, that it's ozone generators will produce the specified quantities of ozone, as described in the product data sheets. Nutech 03 does not guarantee that any specified quantity of ozone will produce water, or any other liquids, of any quality or chemical content. Please direct specific questions to Nutech 03, Inc.
» What is Ozone?
Ozone is formed naturally in the atmosphere, as a colorless gas having a very pungent odor. Ozone, chemically, is the triatomic, allotropic form of oxygen having the chemical symbol 03 and a molecular weight of 48. Ozone, under standard atmospheric temperature and pressure, is an unstable gas that decomposes readily into molecular oxygen.
Ozone is a very powerful oxidant, with a redox potential of 2.07 and it has many commercial and industrial applications. It is used commercially in potable and non-potable water treatment, and as an industrial oxidant. The considerable oxidizing power of ozone and its molecular oxygen by-products make it a first choice for oxidation or disinfection.
» A Brief Look at Ozone
In 1785, Van Marum noticed that air near his electrostatic machine acquired a characteristic odor when electric sparks were passed. In 1801, Cruickshank observed the same odor at the anode during the electrolysis of water. In 1840 Shonbein named the substance, which gave off this odor, "ozone", from the Greek word "ozein" - to smell. In 1857 Siemens designed an ozone generator that has since evolved into the present day, cylindrical dielectric type that makes up most of the commercially available ozone generators in use, and which has sometimes been called the "Siemens Type" ozone generator.
The first drinking water plant to use ozone was built at Oudshoom, Holland in 1893. Another, drinking water plant began operations at Nice, France, in 1906. Since Nice has been using ozone since that time, it is generally referred to as the "birthplace of ozonation for drinking water treatment.".
Ozone has rapidly gained public acceptance, in the United States, with the introduction of the modem ozone generating equipment. This new technology makes it feasible to generate substantial concentrations of ozone for a multitude of applications. Recently, ozone has been granted G.RA.S. status (generally recognized as safe) by the U.S. Food and Drug Administration. (F.D.A.)
» Advantages Compared With Disinfectants and Oxidants
Ozone bas several significant advantages over its chemical alternatives:
» Oxidants and Reaction Potentials
- Ozone can be generated on-site.
- Ozone is one of the most active, readily available oxidizing agents.
- Ozone rapidly decomposes to oxygen leaving no traces.
- Reactions do not produce toxic halogenated compounds.
- Ozone acts more rapidly, and more completely than other common disinfecting agents do.
- Ozone reacts swiftly and effectively on all strains of viruses.
(MATERIAL I VOLTS)
» How Ozone Works
- Free Radical -2.80
- Ozone - 2.07
- Hydrogen Peroxide - 1.78
- Potassium Pennanganate - 1.70
- Hypobromus Acid - 1.59
- Hypochlorus Acid - 1.49
- Chlorine - 1.36
- Chlorine Dioxide - 1.27
- Oxygen - 1.23
- Bromine - 1.09
- Iodine - 0.54 (More Stable)
Ozone acts by direct or indirect oxidation, by ozonolysis, and by catalysis. The three major action pathways occur as follows:
» The Commercial Production of Ozone
- Direct oxidation reactions of ozone, resulting from the action of an atom of oxygen, are typical first order, high redox potential reactions.
- In indirect oxidation reactions of ozone, the ozone molecule decomposes to form free radicals (OR) which react quickly to oxidize organic and inorganic compounds.
- Ozone may also act by ozonolysis, by fixing the complete molecule on double linked atoms, producing two simple molecules with differing properties and molecular characteristics.
Large quantities of ozone are produced commercially in a modem ozone generator, in the same manner that ozone is formed naturally by the discharge of electricity during a thunderstorm.
The passage of a high voltage, alternating electric discharge (A.C.) through a gas stream containing oxygen will result in the breakdown of molecular oxygen, to atomic oxygen. Some of the atoms of oxygen thus liberated reform into ozone, while others recombine to form oxygen. In order to control the electrical discharge, and maintain a "corona" or silent discharge in the gas space, a dielectric space or discharge gap is formed, using a dielectric material such as glass or ceramic. A ground electrode, constructed usually in 316L stainless steel (a material which has demonstrated high resistance to ozone induced corrosion in the gas phase) serves as the other boundary to the discharge gap. This can be accomplished in many ways, but the most frequently employed geometry is that of the cylindrical dielectric (or Siemens Type) ozone generator. The cylindrical dielectric is more space efficient than other shapes and consequently more economical to manufacture.
Ozone produced commercially for oxidation reactions is always produced as a gas, from air at concentrations between 1.0 and 2.0 percent by weight, or from oxygen at concentrations greater than 2% and up to 8% (or greater) by weight Since ozone is highly reactive, and has a short half-life, it can not be stored as a gas and transported, consequently ozone is always generated on site for immediate use.
» Typical Applications for Ozone
Drinking Water Treatment
» Material Safety Information
When ozone is applied, as a gas, for drinking water treatment, it is done primarily because of its oxidative strength. This powerful oxidation potential allows ozone to be effective in the reduction or elimination of color, after taste and odor, all of which may be fundamental problems associated with a specific water supply. More importantly, ozone will effectively destroy bacteria and inactivate viruses more rapidly than any other disinfectant chemical.
Ozone will also oxidize heavy metals. Iron and manganese can be reduced to very low, safe levels in water supplies through ozone oxidation. 11rls same process is used to liberate organically bound heavy metals, which are otherwise not easily removed.
When properly applied at the start of a water treatment process, ozone will not lead to the formation of halogenated compounds such as Trihalomethanes (THM's) which are formed when chlorine is added to the raw water containing humic materials. Once a THM is formed, it is quite difficult, if not impossible to oxidize, even with ozone. Thus, ozone can be used as an oxidant, where it is applied at the latter stages of water treatment
There are more than two thousand installations worldwide that use ozone to treat drinking water. In Canada, there are over sixty water treatment plants, which use ozone in some capacity. Due to the implementation of the Environmental Protection Agency's, Safe Drinking Water Regulations, the use of ozone in the treatment of drinking water in the United States has increased dramatically. More than two hundred and fifty ozone treatment plants are now under design or construction in the United States. In the next five years many hundreds of larger municipalities will be adding ozone to their water treatment plants.
As water treatment plants respond to EP A regulations, more than 10,000 smaller drinking water treatment facilities will be considering adding the ozone oxidation processes to their drinking water treatment.
Ozone is an effective disinfectant for treating municipal and industrial wastewater, enabling the end user to meet E.P.A. pre-treatment standards. Ozone is effective in treating numerous complex, toxic chemicals including:
Hydrogen Cyanide, Acetic Acid, Propane, Formaldehyde, Liquefied Petroleum Gas, Butoxythanol, Isopropyl Alcohol, Methyl-Ethyl Ketone, Benzene, n-Butyl Phthalate Camphor, Para-Phenylenediamone, Styrene, Xylene, Acetone, Cetyl Alcohol, Glycerol, Propylene Glycol, Benzyl Alcohol, n-Butyl Acetate, Mythelacrylic Acid, Triccresyl Phosphate, Toluene, Mineral Spirits, Ammonia, Ammonium Persulfate and Non-Ionic Detergents.
For some compounds, it may be necessary to combine ozone treatment with ultra violent light or ultra sound to increase reaction time. Quantities of ozone required to treat a specific chemical compound, and the required contact time, will vary.
The treatment of wastewater with ozone, again primarily for disinfection was a key focus of its application in the United States, during the late 1970's and early 1980's. The main use of ozone was however, disinfection. This approach is again being considered in light of the desire to avoid using chlorine as the primary disinfectant.
Ultra-pure and De-ionized (D.I.) Water Systems
The use of ozone in the printed and integrated circuit board industry for the production of Ultra-pure water is a well-documented application. Ozone is also applied to the de-ionized water that is used to wash substrates during the production of printed circuit boards.
The application of ozone or ozone in combination with other chemicals for the treatment of malodorous air has a long history of success. Typically, in wastewater treatment plants, foul air can be collected and treated with ozone to reduce the odor. Ozone is usually applied in combination with wet scrubbing equipment.
Using ozone instead of chlorine has some significant advantages. First, the ozone can1er gas will increase the dissolved oxygen level in the fish tanks. Second, the fish will not be exposed to the by-products of chlorination with all the ramifications that are entailed. Dosage rates for fish hatcheries are typically in the same order of magnitude as for low level water treatment.
Ozone is rapidly becoming the oxidant of choice in many industries as they look for alternatives to chlorine. Ozone is used extensively as a process gas for manufacturing in a wide range of industries. Water dependant industries, such as commercial laundries, are utilizing ozonation as a way to reduce both chemicals and wastewater discharge, while maintaining superior disinfection due to ozone's strong oxidation powers.
Pulp and Paper (bleaching, wastewater disinfection)
As general negative reaction to the dispersion of waste effluents containing chlorinated disinfection by-products grows, the consideration of the use of ozone in the many phases of the pulping process grows. It should be pointed out that the pulp and paper industry has been examining the use of ozone for many years. Ozone can be applied as a final polishing treatment to the waste effluent from the plant. Ozone is also applicable in the bleaching process and, similar to wastewater plant foul air deodorization, can be applied to the odor which emanates from the process.
Other Applications of Ozone:
Air Pollution Control (Odor Control)
Aquaculture / Fish Farms (Disinfecting)
Bleaching (Paper & Pulp)
Bottled Water / Beverage Industry (Bottle & Can Sterilization/Process uses)
COD/BOD Reduction (Water & Wastewater)
Cold Storage Facilities (Cooling Towers)
Commercial Car Wash Operations (Water & Wastewater, Chemical reduction) Containers and Food Storage Tank Wash Down (Sterilization)
Cooling Tower Treatment (Bio-fouling control/Chemical replacement)
Cyanide Destruction (Wastewater)
Disinfecting (Water & Wastewater)
Drinking Water (Pre / Post treatment)
Dye Removal (Reuse)
Food Processing (Sterilization / Fruit Washing)
Heavy Metals Reduction (Wastewater)
Landscape Architecture (Fountains, Mirror Ponds, Waterfall Bio-fouling control)
Laundry Water - Commercial (Chlorine replacement-Low temperature washing - Recycling) Medical Applications (Equipment Sterilization)
Micro Flocculation of Suspended Solids (Chemical Alternative)
Odor Removal, Control and Elimination (Water & Air)
Organic Oxidation (Water & Wastewater)
Pesticide Removal (Water & Wastewater)
Pharmaceutical Industry (Process & Ultra purity)
Swimming Pools and Spas (Chemical Alternative)
Textile Processes (Dye removal)
Turbidity (Water Clarity, Water & Wastewater)
Ultra-pure / D.I. Water (Semiconductor Manufacturing)
Wastewater Treatment (BOD / COD reduction)
Water Reuse Applications (Disinfecting & Chemical reduction)
Zoos and Public Aquariums (Disinfection - Sanitation]
* Treating contaminated water with ozone will, in many instances, enable the end user to meet U.S. E.P.A. pretreatment standards.
Product Name: Ozone Synonyms: Triatomic Oxygen, 03 Chemical Family: Oxidizer Molecular Formula: 03 Molecular Weight: 48.0
Components: Ozone Gas Concentration: 0-20% by weight Gas Registry Number: 10028-15-6
Solubility in Water by weight at 20 C: 0.003 g/l (3 ppm)
Appearance and Odor: Ozone is colorless at all concentrations experienced in Industry. It has a very pungent characteristic odor usually associated with electrical sparks. Ozone odor is generally detectable at concentrations of 0.02-0.05 ppm.
This information is being provided to give a general overview of ozone and its uses. This information is not meant to be used for engineering and designing of any Ozone based water treatment system. Nutech 03, Inc. makes no claims as to the accuracy of this information.