“References: Bader H. and J. Hoigné, “Determination of Ozone in Water by the Indigo Method,” Water Research Vol. 15, pp. 449-456, 1981. APHA Standard Methods, 23rd ed., Method 4500-03 B-1997.
With the indigo method, indigo trisulfonate dye immediately reacts with ozone. The color of the blue dye decreases in intensity in proportion to the amount of ozone present in the sample. The test reagent is formulated with malonic acid to prevent interference from up to at least 10 ppm chlorine. Results are expressed as ppm (mg/L) O3.The CHEMetrics Indigo Ozone Vacu-vials® Kit employs an innovative “self-zeroing” feature to eliminate the need to generate a reagent blank. Each Vacu-vials® ampoule is measured before and after being snapped in sample. The change in color intensity, measured in absorbance, between reagent in the unsnapped and snapped ampoule is used to determine the ozone concentration of the sample.”
The indigo test kit can be purchased at the Oxidation Technologies web store. Indigo test kit.
The I-2022 Dissolved Ozone Meter is designed for accurately and quickly measuring ozone in water levels from 0 – 0.75 ppm. This device uses the Indigo Method for testing. This method is based on the colorization of dye by ozone, where the loss of color is directly proportional to the ozone concentration. The results are then displayed on the monitor in ppm (mg/L) of ozone present.
This device has LED display for precise and accurate readout and is easy to use. Once the I-2022 has been purchased the cost per test is only $1.02.
Next, use the dilute method to measure higher concentrations of ozone.
The Indigo snap method test kits will measure up to 0.75 so a dilute procedure can be used to derive an accurate measurement. The video uses the K-7404 kit which used the DPT method, but the principle can be applied to the Indigo kit as well.
Feel free to contact Oxidation Technolgies with any ozone questions.
Our journey to the center of an ozone generating plasma cell begins with a ride around a not-so-lazy river. Perhaps you’ve enjoyed floating in a raft around a lazy river at a hotel or water park. Picture these rafts as electrons flowing through a circuit. Moving magnetic fields are pushing electrons through the fluid media of metal atoms. They follow the circular paths of circuits like rafts floating around and around the lazy river ride. A pump continually pushes the water along.
Unlike the continuous flow in one direction of direct current (DC), alternating current continuously reverses the flow of electrons. Imagine the lazy river model constantly changing direction. The electrons first flow one way, slow, reverse, and rush the other way. The electric supply to your home goes through 60 cycles per second. Our lazy river model begins to defy imagination at this rate of change. You can think of electrons as virtually weightless, unlike all the water and rafts in a lazy river. Electrons are quite capable of reversing direction very quickly.
Energy Transfer The flow of electrons through a wire might be apparent from the glow of a light bulb. As electrons squeeze through a resistive part of the circuit, the wire heats up transferring energy to heat and light. Other things are happening outside the wire. Hold a compass near a wire in which current is flowing, and the needle is pulled away from North. Whenever an electric current flows, a magnetic field develops around the wire. Stop the flow, and the field collapses.
Wrap this conductor into a coil, and the magnetic field is intensified. Add an iron core, and a magnet is born. A continuous flow supports a useful magnetic field, capable of pushing the rotor of a motor or the lever of a switch. Again we notice a transfer of energy, this time from electric current flow to some mechanical motion. Energy transfer doesn’t stop there.
Energy transfer is reversed in a magnetic field when the electric current stops. When current stops or reverses, the magnetic field collapses. The collapsing magnetic field gives electrons a push in the coiled conductor. This phenomena opens up the possibility of generating a flow of electrons in a second circuit that is isolated from the first circuit. It also introduces radio waves. Imagine a second lazy river next to yours. It doesn’t have a pump, so the water is still. But imagine an invisible force generated by the flowing of the first river pushing the water along in the second. Such a transfer of energy happens with the flow of electrons and is essential to ozone production within a plasma cell.
A Dam in the River: The Plasma Cell Heart
A dam in the lazy river brings the rafts to a halt, but build two Olympic sized pools on either side of the dam. Now the river continues to flow awhile even with a dam because it takes time to fill the pool. Depending on the strength of the pump, the water flows for a while as one pool gets a little deeper while the other is drawn down. If you can pump one pool much deeper than the other, a significant stress builds on the dam. Our lazy river could get exciting if the dam were to burst. We are getting closer to the center of a plasma cell.
In your mind you need to convert the Olympic sized swimming pools in our lazy river circuit to large flat pieces of metal. In the electron world, the dam between these two plates is an insulator, a material that prevents the flow of electrons. Electrons pile up on one side while they are drawn down on the other side. Electrons are the negative charge. Pulling electrons away leaves one side with deficiency of electrons: a positive charge. If the insulator were breached, a powerful surge of electrons would create a dramatic spark. It would be equivalent to the deep swimming pool emptying to the shallow one in milliseconds.
It is here at the “dam” where we discover the center of a plasma cell. When the distance between the two electrically charged plates is made smaller, the electrostatic forces between them grow exponentially. In other words, a thinner dam makes a more powerful electrostatic field. But a thin dam is also weaker and more susceptible to failure. The goal is a material that is strong and a good electrical insulator. Ceramic and quartz serve well for this purpose. But without some oxygen present in this high electrical pressure environment, we only have a capacitor and no ozone production.
We need to introduce one more element: a thin layer of oxygen as part of the “electron dam.” We can think of the dam as a sandwich of two insulators with a very thin slice of oxygen between them. When oxygen is exposed to the tremendous electrostatic forces found within this space between highly charged surfaces, the oxygen molecules are pulled apart and re-combine in highly energized forms. I would like to zoom in for a closer look at this sliver of space.
A Peak Inside the World Between Dielectric Barriers
Photographs of this space between the two insulators reveals what appears to be a mini, but intense electrical storm. We are used to thinking about lightning bolts jumping from one charged conductor to another, but in this electrostatic microcosm, the mini “bolts of lightning” are jumping from the surface of one insulator to the surface of the second insulator. In the presence of the strong electric field, the molecules within the insulator become polarized. This means that the electrons are pulled by the positive electrode toward one end of the molecule that make up the insulator. Even though electrons are unable to flow through the insulator, the polarization sets up “pools” of electrons on the surface. We call the insulating material used in in this application a “dielectric.” The type of ozone generator we are entering here is a dielectric barrier discharge (DBD) generator.
Exactly what is happening in this high electrical pressure world between dielectric barriers has been and continues to be a topic of considerable research and study. Already around 1897, John Townsend discovered that the strong electric field in the oxygen space between dielectrics initiates electron avalanches. A free electron among the oxygen atoms accelerates very quickly because it is attracted to the positively charged plate (anode). When it reaches a high enough velocity and collides with an oxygen molecule, it knocks off another electron, turning the molecule into a positively charged ion. This ion begins to move in the opposite direction toward the negatively charged plate (cathode) while the two electrons further accelerate toward the anode and collide with more oxygen molecules. As the growing electron cloud races toward the anode, it leaves a trail of positively charged ions in its wake.
This trail of ions and free electrons is conductive, and allows for a discharge of electric current through the oxygen. The discharge is the flow of electrons that has gathered on the surface of the dielectric towards the positive charge on the other side of the oxygen gap. It is this discharge of energy that breaks the oxygen molecule bonds releasing free oxygen atoms. Some re-combine with single atoms, and others combine with pairs to form highly energized ozone molecules made of three oxygen atoms. The world here at the center of an ozone generator is a stormy one swarming with surges of electrons.
DBD: A Specialized Form of Corona Discharge
The discharge is similar to a spark, but not nearly as hot. It does not result in a discharge of the electrodes. Only small areas of the inside surface of the dielectric discharge with each electron avalanche. The strong electric field induces a secondary, high voltage mini-circuit within the oxygen gap. Thousands of these discharges can be repeated as long as the voltage supplied to the anode and cathode continues to increase.
The power supply for an ozone generator alternates this electric field thousands of time each second. When the pressure (voltage) rises through the threshold that sets off electron avalanches, the discharge storm erupts. Since the electric field changes thousands of times each second, the oxygen gap experiences thousands of storms each second. The optimal frequency and voltage depends on the gap size and oxygen pressure. The electronics controlling the voltage need to be tuned to match the particular dielectric arrangement for optimal ozone production.
The benefits of setting off thousands of mini discharges in a space between insulators instead of simply allowing a spark to ark between the positive and negative electrodes are the following: 1) an arc generates so much heat that it melts most materials. Such an arc is useful for welding or plasma torches, but would destroy an ozone generator. 2) Ozone production is minimal with an arc. Most of the energy is converted to heat and the heat destroys ozone. 3) Producing many small discharges from dielectric surfaces within a strong electrical field stays cooler and yields more ozone.
This form of ozone generation is called “Dielectric Barrier Discharge” (DBD). DBD belongs to a category of corona discharge. Corona discharge was observed by ancient sailors on the masts of their ships as a flare of luminous plasma at the tips of the mast and other pointed parts of their ship when the atmosphere is highly charged. The phenomenon occurs when strong electrostatic forces concentrate at sharp points and break down air to form plasma. You can observe this phenomena with an electrostatic generator in a dark room. Many of the small ozone generators sold for home use rely on a form of corona discharge from sharp points. Higher quantities of high concentration ozone used in commercial applications often use DBD type ozone generators.
Ozone can also be produced with ultraviolet light and radiation bombardment. The ozone layer which protects earth from harmful radiation is produced by ultraviolet light with a wavelength less than 200 nm. Ultraviolet light between about 200 and 300 nm destroys ozone. The ozone layer is maintained with a balance of ozone generation and destruction with ultraviolet light. Ozone can be created in water with electrolysis. Passing an electric current through water breaks the water molecules into hydrogen and oxygen. Using specific electrodes results in oxygen combining to form ozone.
Here at Oxidation Technologies we do not build DBD plasma cells, but we rely on companies who continue to research and build quality generators for a wide range of applications. We specialize in integrating the right ozone generators into specific applications. Dissolving ozone into water requires ozone generators that make higher concentrations of ozone. Many applications can utilize low pressure or even slight vacuum to minimize the danger of ozone leaks. Sometimes controlling precise levels of low ozone concentrations can best be attained with an ultraviolet ozone generator. Whatever your application, we have the expertise to integrate the right ozone generator to your process.
Every day, pharmaceutical companies around the world produce tons of products that people use to enhance their quality of life. This realm of products has been lumped into a category called “Pharmaceuticals & Personal Care Products,” (PPCPs). These products and drugs do not disappear, but are found increasingly in the water being discharged from wastewater treatment plants. The impact that this cocktail of chemicals has on the animals and people dependent on this water is not fully understood, but the evidence is clear that it is not good.
Ozone is a powerful oxidant capable of breaking troublesome molecules. What impact does ozone have on PPCPs? A recent laboratory study published in the engineering journal of the International Ozone Association (IOA) exposed water containing thirty seven different PPCPs to investigate the degradability of these chemicals.
Eight of the thirty five were very quickly degraded to or below their limit of detection with a dissolved ozone dose of 1ppm within 5 minutes. Five more were degraded with a dissolved ozone dose of 2ppm within 5 minutes. Five more required at least 10 minutes of retention time at 2 ppm.
The other half of the thirty five required more time and a higher dose of ozone. Three of them, (DEET, Ketoprophen, and Primidone) did not degrade below their limit of detection even when exposed to 9ppm of dissolved ozone for 15 minutes.
Ozone clearly has a significant role to play with PPCP cleanup. Further study is sure to discover ways to optimize the process and make it more effective. Oxidation Technologies specializes in integrating ozone into the specific process of diverse customers. We continue to pursue a better understanding of ozone use in a variety of applications.
N. Evelin Paucar, Ilho Kim, Hiroaki Tanaka & Chikashi Sato (2019) Ozonetreatment process for the removal of pharmaceuticals and personal care products in wastewater, Ozone: Science & Engineering, 41:1, 3-16, DOI: 10.1080/01919512.2018.1482456
Legionnaires’ disease is a bacterial pneumonia caused by breathing mist from water containing the bacteria. The bacteria thrive in the warm water found in whirlpool spas, cooling towers, fountains, humidifiers, produce misters, etc. Symptoms of Legionnaires’ disease include high fever, a cough, and sometimes muscle aches and headaches.
The rate of reported cases has increased over 5 fold since 2000, and deadly outbreaks continue today unabated. The reason or reasons behind this increase are unclear at this point, but ozone has proven to be effective at controlling the bacteria in water. Whether the bacteria are flourishing within a 100 gallon fountain or a 1000 ton cooling tower, the engineers at Oxidation Technologies will maintain will provide the precise dose of ozone needed for safe water.
Ozone that is safely dissolved into water has a tremendous disinfectant power and simply turns back into oxygen after expending its energy. As little as 0.01 ppm (1 part ozone to 100 million parts water) prevents the growth of these bacteria. We provide cost effective equipment and long term service to ensure safe and effective use of ozone for bacteria control.
The equipment needed to dissolve low levels of ozone into water can be very cost effective and sustainable for many water systems. A home well-water system uses one of the smallest ozone generators we sell to dissolve enough ozone when the well pump runs to disinfect all the water needed in a typical home. As a general rule of thumb for industrial cooling towers, five grams of ozone per hour is needed for every 100 tons of tower cooling capacity.
The 50 g/h ozone generator needed to supply a 1000 ton cooling tower will also require an oxygen concentrator, venturi, ORP controller, and sometimes a booster pump. The oxygen concentrator and controller comes in a complete package with our OXG systems. The following study conducted by Mazzei reports a one year payback for ozone use due to lower chemical and cleaning costs.
We also provide the convenience of a quarterly preventative maintenance plan to make sure the system continues to perform at peak efficiency and avoid costly repairs due to neglected maintenance. We often work with an independent water company that provides routine testing for the customer to make sure water quality remains good and inform us of any problems.
High iron content in water often results in disagreeable metallic taste and unappealing color in cooked vegetables. Although not a health threat, iron bacteria thrive in this water and contribute to biofilm and discoloration. Dissolved iron eventually leads to ugly stains on fixtures and clogged pipes. Removing iron from your water supply is well worth the investment.
The most common piece of water treatment equipment for homeowners is the water softener. Your water softener is designed to remove calcium from the water. It may remove some of the iron, but iron is prone to stick to the resin bed and is difficult to flush out.
An iron filter is a much more effective method for removing iron. There are a variety of filter systems, but they all follow the two step process of oxidizing the iron and then filtering it out. Iron that is dissolved in water can’t be filtered out until it is oxidized or made into larger rust particles that are large enough to be filtered.
Simply aerating water containing dissolved iron will begin the oxidation process needed for filtration. This method is simple, but can introduce some new problems such as increased bacteria growth. It is also slower and difficult to control effectively.
Some compact home iron filtration devices contain media which accelerates the oxidization process and also serves as a filter to remove the oxidized particles. Like a water softener, these systems require periodic back flushing and eventually require chemical regeneration. The effectiveness of these systems is dependent on PH levels and do not disinfect the water. Iron bacteria can still cause problems by leaving ugly stains on water fixtures.
Adding a chemical feed pump to introduce chlorine, calcium hypochlorite or potassium permanganate increases the oxidation. These systems are able to remove higher iron levels and also serve to disinfect the water. The disadvantage is the ongoing cost of dangerous chemicals.
Ozone has been used for water treatment for over a hundred hears. It is used extensively for bottled water treatment because it is an effective disinfectant and improves taste and color. Oxidation Technologies specializes in harnessing the power of ozone for a variety of water treatment needs.
During some recent lab testing I had some high concentration dissolved ozone solution to play with. It was easy to see a 50 ppm ozone solution rapidly destroying color molecules in water. Ozone breaks apart bacterial, viruses and other water contaminants like it breaks apart the color molecules. Here at Oxidation Technologies we do a variety of product exposure testing with ozone. We are always happy to talk to you about harnessing the power of ozone for your application. Give us a call at 515-635-5854. Check out our website for fast and easy source of all ozone related supplies.
Efficient and accurate ozone production requires accurate measurements of gas flow rates. The rota-meter style flow-meter is a simple, robust, and accurate way to measure the flow of gas or liquid. The only moving part is a metal ball (float) within a tapered transparent tube. As flow rate increases, the ball rises. Try out this quick, one-question quiz to test your ability to read this instrument.
One limitation to this device is its inability to factor in gas pressure in a direct reading. Gas under pressure is squeezed together so more gas is able to flow past the ball than it reads. Some flow-meters are calibrated for a specific gas pressure. Such meters are accurate only at that pressure. This limitation is easily overcome with a simple calculation. You can calculate an accurate flow rate at any pressure when you know the gas pressure of the gas flowing through the meter. How did you do on the quiz? If you haven’t tried it yet, check out our calculator page for better chance of getting it right.
Our lab was doing some ozone exposure testing on a water sample and I noticed a beautiful magenta color developing. Toward the end of the exposure test, the foam in the water column began to take on a pinkish color. When the ozone was turned off, the foam quickly reduced to the magenta colored liquid you see in the picture. After a few minutes, it became colorless again. Intrigued, I asked why it changed colors, and learned that it had to do with Manganese Dioxide. I did some further research, and learned that Manganese has a number of oxidation states from +2 to +7. Manganese is often found dissolved in water. As such it can not be filtered from the water. Ozone will oxidize the manganese to manganese dioxide MnO2 which is particulate and can then be filtered from water. Further ozone exposure as was done in the water sample eventually forms soluble permanganate MnO4- which has a purplish color. See our water treatment equipment for removal of iron and manganese from well water.
Last year we did some lab testing that required water with a dissolved ozone concentration over 100 ppm. https://www.oxidationtech.com/blog/the-color-of-ozone/. Here we could distinctly see the bluish color of ozone. The intense colors only hint at the power of ozone even in much lower concentrations.
Oxidation Technologies will custom build a wide variety of specialized ozone applications. In the 9 months I have been working here, few projects have been the same. We have designed and built specialized pilot systems for customers exploring the new applications for ozone in their industry. We’ve produced a variety of systems for sanitation in the food industry and organic food storage. Our systems are solving tough problems in the pet products industry, and pharmaceutical research. We design systems for applications from bottled water treatment & dairy operations to municipal water, groundwater remediation, and sewage treatment. Our systems are helping customers in the ocean well drilling as well as the airline industry. We have designed custom treatment chambers for laboratories, allergy treatment, and product treatment. We’ve done in-house materials testing on a variety of dry and liquid materials. We continue to develop precise and safe control systems. Oxidation Technologies support the whole spectrum of ozone as well as other gas use with analyzers, sensors, parts and supplies. We have worked with customers all around the world. Everyone here works hard to understand needs and develop systems that will meet those needs. The leadership here have a tenacious spirit for overcoming obstacles and refuse to give up. The phones here are always in use providing excellent customer service. We are willing to travel and visit sites when needed or on a routine maintenance basis. From design to build, every project is steeped in cost consciousness, quality, the best materials and equipment for the job. Systems are built to work well, and last for a long time. After nine months working here, I continue to grow in my appreciation for the amazing potential of ozone, the depth of expertise laying the foundation of Oxidation Technologies, and the integrity and enthusiasm for applying the power of ozone to meet customers’ needs. At the same time, I have come to realize that what I have seen so far is only the tip of the iceberg. I am confident that the culture of growth and learning here will nourish my growth in understanding ozone and our ability to harness the power of ozone for your needs.
Recently Oxidation Tech updated our calibration chamber and process. We have been using a smaller chamber or individual processes to calibrate each sensor we receive one by one. With our new calibration chamber, we can calibrate as many as 10-15 ozone monitors at one time.
This calibration chamber still uses our Thermo Fischer Transfer Standard Ozone Analyzer to measure and control ozone levels inside the chamber. However, with the use of an external ozone generator and automated control system a precise ozone level can be maintained inside the chamber at all times. This saves time and potentially provides a higher quality, more accurate calibration for your device.
Our ozone calibration chamber can also be used to high range calibrations up to 1,000 ppm, or can be used for ozone exposure testing. As this sealed chamber has great capacity and automation any device a customer may need to be exposed to ozone can be placed in the chamber to be exposed to known and tightly controlled ozone levels.
We also offer ozone exposure testing for higher range ozone levels, and lower range ozone levels in a smaller chamber. Ozone exposure chambers are also a part of our standard product line as these are a popular requirement for many material testing facilities.