Ozone – an introduction
Ozone has been used for disinfection of drinking water in the Municipal Water Industry in Europe for over 100 years and is used by many Water Companies, where ozone generator capacities more than 100 kg/h are common.
Ozone can be used for water and air treatment. Most infections occur because of the invasion of anaerobes that do not thrive in an oxygen rich environment. Depriving the cells of oxygen encourages anaerobic microbes to flourish. An abundance of harmful microbes will cause a breakdown of enzymatic reactions, an overload of metabolic wastes and eventually the cells will die.
Ozone is sometimes called “Breath of the Gods” as it is powerful.
Ozone is a bluish water-soluble gas with a distinct smell and a long history therapeutic use. The name ozone comes from the Greek word “ozein” which means smell. The equivalent Hebrew word means “the Breath of God”.
Ozone – safe for the environment with the proper ozone generator system
Because ozone is made of oxygen and reverts to pure oxygen, it vanishes without trace once it has been used. Compare this with other disinfectants.
When Ozone disinfects or breaks down harmful bacteria or pollutants, there are generally no by-products, unlike most disinfecting agents.
History of ozone
Past developments in ozone application
A Dutch chemist called Van Marum was probably the first person to detect ozone gas sensorially. In the description of his experiments, he mentioned the notion of a characteristic smell around his electrifier.
However, the discovery of ozone was only just mentioned by name decennia later, in a writing of Schönbein that dates back to 1840. This discovery was presented to the University of München. Schönbein had noticed the same characteristic smell during his experiments, that Van Marum had tried to identify earlier. He called this gas ‘ozone’, which is distracted from ozein; the Greek word for scent. Generally, the discovery of ozone is ascribed to Schönbein. Moreover, Schönbein is mentioned as the first person to research the reaction mechanisms of ozone and organic matter.
After 1840, many studies on the disinfection mechanism of ozone followed. The first ozone generator was manufactured in Berlin by Von Siemens. This manufacturer also wrote a book about ozone application in water. This caused many pilot projects to take place, during which the disinfection mechanism of ozone was researched.
The French chemist Marius Paul Otto received a doctorate at the French University, for his essay on ozone. He was the first person to start a specialized company for the manufacture of ozone installations: ‘Compagnie des Eaux et de l’Ozone’.
The first technical-scale application of ozone took place in Oudshoorn, Netherlands, in 1893. This ozone installation was thoroughly studied by French scientists, and another unit was installed in Nice after that (in 1906). Since then, ozone was applied in Nice continuously, causing Nice to be called the ‘place of birth of ozone for drinking water treatment’.
In the years prior to World War I, there was an increase in the use of ozone installations in various countries. Around 1916, 49 ozone installations were in use throughout Europe (26 of which were located in France). However, this increase faltered soon afterwards. This was consequential to research of toxic gases, which evidently lead to the development of chlorine. This disinfectant appeared to be a suitable alternative to ozone, as it did not have the shortcomings in management, such as low applicative guarantee and low yield of ozone generation. Ozone production did not reach its prior level until after World War II. In 1940, the number of ozone installations that were in use worldwide had only grown to 119. In 1977 this number, had increased to 1043 ozone installations. More than half of the installations were in France. Around 1985, the number of applied ozone installations was estimated >2000.
Today, chlorine is still preferred over ozone for water disinfection. However, the last decennia the application of ozone applications did start to increase again. This was caused by the discovery of trihalomethanes (THM) as a harmful disinfection by product of chlorine disinfection, in 1973. Consequentially, scientists started looking for alternative disinfectants.
Another problem was an increase in disturbing, difficultly removable organic micropollutants in surface waters. These compounds appeared to be oxidized by ozone faster than by chlorine and chlorine compounds.
Furthermore, ozone turned out to deactivate even those microorganisms that develop resistance to disinfectants, such as Cryptosporidium.
Finally, there has been a progress in the abolishment of shortcomings in ozone management.
QUESTION: WHAT IS OZONE?
ANSWER: Ozone is a molecule that consists of three oxygen atoms (O3), with a delta negative and a delta positive electric charge. The ozone molecule is very unstable and has a short half-life. Therefore, it will decay after some time into its original form.
In essence, ozone is nothing more than oxygen (O2), with an extra oxygen atom, formed by an electric high charge an extra oxygen atom. In nature ozone is produced by some chemical reactions. The most familiar example is of course the ozone layer, where ozone is produced from the sun’s ultra-violet (UV) rays. But ozone is also produced at thunderstorms and waterfalls. The extreme high voltages attended with thunderstorms produce ozone from oxygen. The special “fresh, clean, spring rain” smell is a result from nature-produced ozone. Ozone derives from the Greek word ozein, which means to smell. Ozone is a bluish water-soluble gas with a distinct smell and a long history therapeutic use. The name ozone comes from the Greek word “ozein” which means smell. The equivalent Hebrew word means “the Breath of God”.
Ozone is only produced under extreme circumstances. This can also be created by ozone generators. Ozone generators produce ozone with extreme high voltages or with UV-light.
QUESTION: HOW DOES OZONE WORK?
ANSWER: Ozone operates according the principle of oxidation. When the static loaded ozone molecule (O3) contacts with something “oxidation able”, the charge of the ozone molecule will directly flow over. This is because ozone is very instable and likes to turn back in its original form (O2). Ozone can oxidize with all kinds of materials, but also has smell and microorganisms like viruses, moulds and bacteria’s. The extra oxygen atom releases from the ozone molecule and binds with the other material. Eventually remains only the pure and stable oxygen molecule.
Ozone is one of the strongest oxidation agents technical available for use to oxidize solutes. The extra-added oxygen atom will bind (=oxidation) in a split second to every component that comes into contact with ozone.
Ozone can be used for a broad of area of purification. For the biggest part ozone is applied in the municipal wastewater and potable water treatment plants (for disinfection). However, ozone is used more and more in the industrial branch. In the food industry for example ozone is used for disinfection and in the paper- and textile industry it is used for the oxidation of wastewater. The main benefit of ozone is its clean character, because it only oxidizes materials, with forming almost no by-products. Because ozone has a strong recognizable smell, very low concentrations will soon be perceived. This makes it generally safe to work with ozone.
QUESTION: HOW IS OZONE PRODUCED?
ANSWER: Ozone can be produced artificially according the same principle as it occurs in nature, which means by UV light (ozone layer) or via corona-discharge (high voltages, thunderstorm). In both methods the connection between the oxygen molecules is broken up. Consequently, oxygen radicals are produced, which connect with the oxygen molecule to O3 (ozone). For the production of ozone, corona discharge is used more because of the greater advantages of this method. Advantages are the lower costs for ozone production (more cost-efficient) and the greater durability of the system. For the feed inlet ambient air can be used as well as pure oxygen. For pure oxygen, oxygen generators can be used to concentrate oxygen out of air. When pure oxygen is used a higher concentration of ozone can be produced to Ozonate cosmetics take at least 40 days of infusion of the base oil, so it is not an off the shelf product made in mass production as most other cosmetics are
QUESTION: WHAT IS THE HALF-LIFE OF OZONE?
ANSWER: For the purification of water and air, it’s needed to produce ozone on-site. Because of its short half-life, ozone will decay soon when produced. The half-life of ozone in water is about 30 minutes, which means that every half hour the ozone concentration will be reduced to half its initial concentration. For example, when you have 8 g/l, the concentration reduces every 30 minutes as follows: 8; 4; 2; 1; etc. In practice the half-life is shorter because a lot of factors can influence the half-life. Factors are temperature, pH, concentration and concentration and sort solutes. Because ozone reacts with all kinds of components, the concentration ozone will reduce quickly. When most of the components are oxidized, the residual ozone will remain, and the concentration ozone will reduce less fast.