Dissolve ozone in water with bubble diffusers

Ozone gas can be dissolved into liquid with simple bubble diffusers, similar to what is commonly used in the bottom of a fish aquarium for aeration. This is a simple and cost-effective method to dissolve ozone gas into liquid. As ozone is partially soluble into liquid the ozone gas will transfer into liquid immediately at the interface between the ozone gas bubble surface and the surrounding water.

Diffusers implement a gas permeable membrane that will disperse the gas stream into many smaller ozone gas bubbles in the water. As these ozone gas bubbles naturally rise to the surface of the water that ozone will transfer into the water due to contact between the liquid and gas bubble.

Advantages:

  • Low cost
  • Easy to setup
  • Low energy – does not require water pumps or elevated water pressures
  • Simple, reliable operation long-term

Disadvantages:

  • Generally the least efficient method of dissolving ozone into liquid
  • Diffusers can become plugged and may require periodic replacement
  • Difficult to use in pressurized water flows

Ozone gas is partially soluble into liquid. However, using proper methods and equipment high mass transfer efficiencies can be realized with any method of dissolving ozone into water. Review the tips below for success using an ozone gas bubble diffuser in your ozone application.

Fundamentals of ozone solubility:

  • Lower temperatures increase the solubility rate of ozone gas into liquid
  • Higher pressures increase the solubility rate of ozone gas into liquid
  • Higher ozone gas concentrations increase the solubility rate of ozone gas into liquid

Design considerations for your bubble diffuser and column:

Diffuser micron ratings – smaller is better!

Ozone gas bubble diffusers will be rated in micron size, or resulting bubble size the diffuser will create. The membrane that splits the gas stream into small bubbles will have pore sizes, smaller pores will result in smaller bubbles. This pore size or bubble size is normally referred to in a micron rating.

Micron = micrometer. Equal to 0.001 millimeter, or about 0.000039 inch

Smaller bubbles create more surface area of the gas the ozone is flowing in. Greater surface area will increase the ability of ozone gas to transfer into the liquid. See the example below:

Ozone gas bubble size compared

The image above shows the same gas volume (1 ft3) shown in one bubble, 8 identical bubbles, and 512 (8 tall x 8 wide x 8 deep) identical bubbles.

  • One 1 cubic foot sphere = 4.8 ft2 surface area
  • Eight 0.125 cubic foot spheres = 1 cubic foot = 1.2 ft2 each = 9.66 ft2 total surface area
  • Eighty 0.0125 cubic foot spheres = 1 cubic foot = 0.26 ft2 each = 20.8 ft2 total surface area
  • 512 0.001953 cubic foot spheres = 1 cubic foot = 0.07567 each = 38.7 ft2 total surface area

A bubble size ¼ the size (4.8 / 4 = 1.2) results in 8x more bubbles and double the overall surface area.

Relating this to your ozone gas flow. A 25 micron diffeser will create bubble sizes ¼ the size of a diffuser rated for 100 micron therefore creating more than 2x the surface area of gas contacting the water at the same flow-rate of gas flowing into water.

Smaller really is better!

Tank design – skinny is better!

Gas bubbles will naturally rise to the surface of water due to buoyancy. Therefore, the taller your tank, column or ozone tank is the longer your gas bubble will remain in the water increasing the opportunity for the gas to transfer into the liquid.

Taller tanks will also increase the water 

pressure at the bottom of the tank where the ozone gas diffuser will likely be placed. Greater water pressure will increase the natural solubility of ozone gas into liquid. For example:

11.33 feet of water = 5 PSI

5 PSI = 34% increase in ozone solubility vs 0 PSI

Increasing your water column by 11.33 feet will increase your solubility of ozone, or your mas potential ppm of ozone in water by 34%.

1 ppm becomes 1.34 ppm with no other changes.

A great example of separate columns is shown in the image and dimensions below. Both columns are 3 liters in volume, with a change in diameter from 2” to 4” the height is increased from 12” to 58”

If you have the opportunity when desiring your tank or reactor, choose the smallest diameter possible.

Skinny really is better!

Counter Current Flow

Ozone contacting basins can be designed with counter-current flow, where the water flows counter-current to the gas bubbles. While gas bubbles will naturally rise to the surface of the liquid due to buoyancy liquid can be forced into the path of the gas bubble to create additional turbulence. The diagram below shows a simple contactor basin design using baffles to create counter-current and con-current flows of ozone gas to liquid

Ozone gas countercurrent flow with bubble diffuser

This same technique can be applied to any column in flowing water using piping water flowing down a column that ozone gas is rising within. Consider this simple technique when designing your tank or piping system

Full page info on ozone diffusers HERE

Fundementals on ozone solubility into liquid HERE

Understand dissolved ozone vs ozone dosage

Purchase ozone diffusers here

Ozone Dosage vs Dissolved Ozone

Ozone dosage = the amount of ozone applied to the water

Dissolved ozone = the amount of ozone measured in the water

Ozone dosage into water does not equal dissolved ozone in water. Ozone is generated as gas and must be dissolved into water in many applications. As ozone is only partially soluble in water mechanical mixing equipment is necessary to dissolve ozone into water efficiently. There are no systems that will achieve 100% mass transfer of ozone gas into water, therefore the dissolved ozone levels will always be lower than the applied ozone, or ozone dosage rate.

Final measured dissolved ozone levels in water will be affected by water quality contamination, water temperature, and the efficiency of your mechanical mixing equipment used to dissolve ozone into water.

To achieve a specific, targeted dissolved ozone level the oxidizable compounds in the water must be overcome along with any other ozone scavenging conditions, also keep in mind the ozone half-life may come into play depending upon the duration of time used to achieve your target dissolved ozone level.

The quantity of ozone you attempt to put into the water will always exceed the amount of ozone actually absorbed into the solution.

Due to the low solubility rate of ozone gas into a liquid and due to system inefficiencies, a portion of the ozone off-gases without being absorbed into the water. This off-gassed ozone must then be vented outside or destroyed with an ozone destruct unit.

The ratio of ozone gas dosage to the final dissolved level is commonly referred to as the mass transfer rate. This refers to the amount of ozone gas that was measured as dissolved vs the ozone dosage rate. This is commonly referred to as a percentage. Such as a 90% mass transfer rate of ozone would indicate that 90% of the ozone dosage, 1ppm for example, would result in 0.9 ppm of ozone measured in water.

Different methods of ozone injection will achieve different dissolved ozone levels into water due to different efficiencies and mass transfer of ozone into water.  A few examples of these options are shown in the images below:

Ozone dissolved into water with bubble diffusers
Ozone dissolved with a bubble diffuser is simple and cost effective. However, in most cases offers the lowest mass transfer efficiency of any method used and therefore the greatest difference between ozone dosage and measured dissolved ozone in water.
Ozone dissolved into water via pump and venturi
Ozone dissolved with a pump and venturi injector is simple to set-up and fairly efficient. This will mix water in the tank well and achieve higher mass transfer of ozone into water than a typical bubble diffuser due to the forceful mixing action of a venturi.
Ozone dissolved into water via an ozone injection skid
Ozone dissolved into water with an ozone injection skid. In this application a dedicated, pressurized ozone mixing tank can be used to increase mass transfer of ozone into water as ozone solubility increases as water pressure increases. A system like this will have the lowest difference between ozone gas dosed into water and resulting measured dissolved ozone in water.

More info ozone solubility found HERE

Full Webpage on this topic HERE

Measuring Dissolved Ozone in Chloronated Water

How to dilute sample to extend test range

Is there a way to measure dissolved ozone (0.5 to 3.0 ppm) in water with a high chlorine level. Yes, there is a way to to this.

First, be sure to use the Indigo Method.

The Indigo Method

“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.

MAX-Series Oxygen concentrators

We have recently started selling the MAX-Series of oxygen concentrators. This is a great addition to our oxygen concentrator line-up. We believe these units are a higher build-quality, at a lower cost, than the other units we have been selling, and have faster lead-times.

Max Pro O2 Series Oxygen Generator
MAX-10 Oxygen Generator

The MAX-Series oxygen concentrators are available in three sizes:

  • MAX-5 = 5 LPM (10.5 SCFH) oxygen at 7 PSI
  • MAX-8 = 8 LPM (16.8 SCFH) oxygen at 15 PSI
  • MAX-10 = 10 LPM (21 SCFH) oxygen at 21 PSI

The MAX series of oxygen concentrators has the following features that are shared by many other brands of oxygen concentrators:

  • Built-in flow-meter
  • Flow adjusting knob
  • Vibration isolation feet for air compressor
  • Replaceable compressed air filter
  • Mounting/leveling feet
  • Hour-meter

The MAX Series has features that are exclusive to this device that set it apart from the other lines we sell.

  • Built-in oxygen purity meter alarm
  • Oxygen filter
  • Air cooler and moisture trap to remove bulk-moisture from the compressed air supply

Learn more about the MAX-Series at the great video we put together below:

Should you have questions about these units, or any oxygen generator we sell, please contact our technical sales staff for help.

How to Measure Dissolved Ozone Using the I-2019 Digital Handheld Meter

The Chemetrics I-2019 Dissolved Ozone Meter is a handheld, battery operated device with an LCD screen readout of dissolved ozone levels. The items needed for taking a test of the levels of ozone dissolved in water include: the I-2019 meter, a zeroing cylinder, a new testing ampoule, a light cover, a test cup, activator solution, and, of course, the sample of dissolved ozone.

Always remember that the steps for taking the test must be done quickly to avoid O3 breakdown before the test is completed. Ozone reverts quickly back to oxygen (O2), and if too much time passes from when you add the dissolved ozone to the test cup to when you take the reading, the reading will be lower than what the true ozone level is in your application.

These are the steps:
1. Turn on the I-2019 meter by pressing the ON/OFF button. The O3 symbol will appear on the screen.
2. Place the zeroing ampoule in the meter’s sample port.
3. Place the light shield over the zeroing ampoule.
4. Press ZERO/TEST button. The O3 symbol will flash for 8 seconds, after which the screen readout will read 0.0.0.
5. Remove the zeroing ampoule and set that aside. Keep the light shield for the next steps.
6. Fill the test cup to the 25 mL line with dissolved ozone.
7. Add 5 drops of activator solution to the test cup.
8. Place tip of new testing ampoule in sample cup and snap off tip against the bottom of the test cup. The vial is vacuum sealed and will fill instantly with the sample.
9. Dry the vial, place it in meter’s test port, and cover with the light shield.
10. Wait 1 minute for the test to develop.
11. Press ZERO/TEST button. The O3 symbol will flash for 3 seconds, and then the reading of the dissolved ozone level will appear on the meter’s screen.

Purchase I-2019 Battery Operated Ozone Meter here: https://www.oxidationtech.com/i-2019.html

Watch Video Showing the Steps for Measuring Dissolved Ozone with I-2019 Meter:

Resolution of D16 PortaSens III Portable Detector with Ozone 00-1009 Sensor

The D16 PortaSens III Handheld Monitor with the Ozone Sensor part number 00-1009 can have the detecting range set by the user at any range from 0-5 ppm ozone up to 0-200 ppm ozone. The resolution is 0.1 ppm ozone at any range from 0-5 ppm up to 0-49.9 ppm ozone. The resolution of the readout on the screen is 1 ppm ozone when set at the range of 0-50 ppm up to 0-200 ppm. The standard range for this sensor is 0-20 ppm ozone, which has a resolution of 0.1 ppm.

Purchase D16 Handheld Monitor with O3 Sensor 00-1009 here: https://www.oxidationtech.com/d-16-gas-detector.html#970=307

If you already have a C16 or D16 PortaSens monitor and need only the replacement ozone sensor, you can purchase just the sensor cartridge PN# 00-1009 here: https://www.oxidationtech.com/ati-ozone-sensor-00-1009.html

Watch Video Showing Resolution at Various Range Settings:

Video Showing How Resolution of Sensor 00-1009 Increases with Lower Range Settings

How to Wire OS-6 Ozone Monitor to Remote Alarm Panel for O3 Safety Monitoring

The EcoSensors OS-6 Ozone Monitor has a safety control relay built in that is set to activate above the ozone human safety limit of 0.1 ppm. When this relay is wired to the Remote Alarm Panel (RAP-1), a loud audible alarm and flashing light will activate when ozone levels go above 0.1 ppm. This blog explains how to wire the RAP-1 to the safety control relay on the OS-6 Ozone Monitor.

Step 1: Remove the front panel on the OS-6.
Step 2: Insert tip of RAP-1 free cable through one of the nipples on the bottom of the OS-6 monitor.
Step 3: Locate the control relay labeled “ABOVE 0.1 PPM.” Connect the red wire to the Normally Open (N/O) terminal and the black wire to the Common (COM) terminal.
Step 4: Replace the OS-6 front panel.

The OS-6 is now wired to the RAP-1. When mounted on a wall and powered on, an audible and visual alarm will now activate when the ozone levels are above the human safety limit of 0.1 ppm.

Ozone Levels Below 0.1 PPM – Alarm Not Activated
Ozone Levels Above 0.1 PPM – Alarm Activated

Purchase OS-6 Ozone Safety Monitor Here: https://www.oxidationtech.com/os6-ozone-monitor.html
Purchase RAP-1 Remote Alarm Panel Here: https://www.oxidationtech.com/rap-1.html

Watch video showing how to wire OS-6 Ozone Detector to RAP-1:

Ambient air Ozone Scrubber

New Product! Destroy ozone safely in ambient air with the CDA-250 catalytic ozone scrubber.

Catalytic ozone scrubber destroys ozone in ambient air at an air flow-rate of 250 CFM.  Built-in fans flow air past catalyst material designed to revert ozone safely back to oxygen.90% efficient at 250 CFM air flow-rate.

Ambient air ozone scrubber
CDA-250 Ozone Scrubber

Features:

  • 250 CFM airflow rate from internal fans
  • Catalytic material is used for long-life
  • >90% ozone destruction efficiency at high ozone levels
  • The catalyst material is replaceable 
  • Magnetic levitation fans are used for longevity
  • No steel ball bearings or other oxidizable metal parts are used
  • Destruct catalyst is at the inlet, electrical components and fans are exposed to lower levels of azone only.
  • Fans operate on 24 VDC for safety
  • External UL listed 24 VDC power supply provided to power from 120 or 220 VAC power.
  • Handles provided for easy transport or carrying
  • Plastic feet mounted to the bottom provide firm footing on the floor or bench.
CDA-250 Ozone Scrubber

For information on more ozone scrubbers see link below:

https://www.oxidationtech.com/products/accessories/ozone-destruct.html

Ozone air disinfection

Ozone is a very effective disinfectant and is effective against all viruses and bacteria. Ozone operates according the principle of oxidation. Ozone (O3) is instable and will revert to oxygen (O2) on it’s own, or when it contacts something it can oxidize. Living cells found in bacteria and viruses are very susceptible to oxidation. As ozone enters cells, it oxidizes (destroys) their components including the cell wall. Once ozone has entered, the process destroys all essential components (enzymes, proteins, DNA, RNA). When the cellular membrane is damaged during this process, the cell will fall apart. This is called lysis — the disintegration of a cell by rupture of the cell wall or membrane. From this point there is no recovery and the pathogen is inactivated. Due to the direct oxidation ozone causes (loosing the oxygen atom) there is greater energy to ozone oxidation vs other comparable chemicals.

Most commonly ozone is used dissolved into water. When dissolved in water ozone increases the ORP (oxidation reduction potential) of the water, all of the water is now a sanitizer with electrical potential for pathogen inactivation through lysis. When the water (with sufficient ozone levels) contacts a pathogen it will react with that pathogen inactivity it. This is extremely efficient and effective.

Ozone can also be used in the ambient air in the gaseous form for antimicrobial applications. Ozone in air is a spacial consideration.  The air is not charged as water is when ozone is dissolved in water. Air simply has ozone in within it.

An example. 0.1 ppm ozone is the safe limit for humans in air for an 8 hour period of time.  20.0 ppm is a relatively high level used in rooms at times for disinfection.  This means 20 parts of every 1 million parts of the air are ozone.   This ozone molecule needs to react with a pathogen cell to inactivate it. The likely-hood of this in a short period of time is low. 

As ozone reverts back to oxygen quickly and frequently, longer the exposure times increase the odds of ozone reacting with the pathogen. Ozone reverts back to oxygen faster (shorter half-life) as temperatures and humidity increase. Therefore, higher ozone levels, higher temperatures, and higher humidity will increase the opportunity for ozone to react with pathogens on surfaces.

Ozone levels used for sanitation should be chosen based upon the goals and requirements for this space, and the ambient conditions present. Reasonable levels of 5-10 ppm are commonly used. Higher levels are also possible. Keep in mind any natural rubber materials will be damaged by ozone use at high levels over long periods of time. Therefore, keep ozone levels and frequency of use reasonable.

Attached are documents on the use of ozone in air for antimicrobial uses. These are great resources to use to ensure ozone is the right solution for your application. Should you need more specific information let us know, we will provide what we have.

A few options we have for ozone sanitation in rooms are listed below. These systems can also all be used in an HVAC system to maintain low levels of ozone in a building for room air disinfection.

HTU-500

0.5 g/hr ozone production

https://www.oxidationtech.com/products/ozone-generators/o3/htu500.html

The HTU-500 with an internal air pump will produce 0.5 g/hr ozone from 3 LPM air.

Adequate in a 5 m3 space for short-term sanitation applications.

Adequate in a 100 m3 space for low occupied spaces for air disinfection

HTU-500 installed in HVAC system for room air disinfection
HTU-500 installed with HVAC system. Ozone is plumbed into the HVAC system after the fan and after the furnace filter.

VMUS-4 = $1,335

2 g/hr ozone production

https://www.oxidationtech.com/products/ozone-generators/o3/vmus4.html

The VMUS-4 with internal air pump will produce 2 g/hr ozone from 3 LPM air.

Adequate in a 22 m3 space for short-term sanitation applications.

Adequate in a 450 m3 space for low occupied spaces for air disinfection

VMUS-4 wall mount ozone generator for use with HVAC system
VMUS-4 wall-mount ozone generator

VMUS-4 + pump + Air drer = $2,455

4 g/hr ozone production

https://www.oxidationtech.com/products/ozone-generators/o3/vmus4.html

https://www.oxidationtech.com/vmd-8.html

The VMUS-4 with external air pump will produce 4 g/hr ozone from 8 LPM air flow

Adequate in a 45 m3 space for short-term sanitation applications.

Adequate in a 900 m3 space for low occupied spaces for air disinfection

VMUS-4 ozone generator with air dryer and pump for room air disinfection
VMUS-4 installed with an external high-flow air pump and air dryer.

VMUS-4 + Oxygen = $2,682

10 g/hr ozone production

https://www.oxidationtech.com/products/ozone-generators/o3/vmus4.html

https://www.oxidationtech.com/max-series.html

The VMUS-4 with oxygen concentrator will produce 10 g/hr ozone from 6 LPM oxygen

Adequate in a 100 m3 space for short-term sanitation applications.

Adequate in a 2,000 m3 space for low occupied spaces for air disinfection

Oxygen can also be provided from external source, or from a portable oxygen bottle.

VMUS-4 installed with an oxygen concentrator to produce 10 g/hr ozone.

Ozone monitoring and control

For control purposes, an ozone monitor can be used. This can turn the ozone generator ON/OFF based on safe levels of ozone, or verify that ozone levels achieved the desired level for disinfection.

OS-6 remote ozone monitor

  • 0-20 or 0-50 ppm range
  • 0.01 ppm resolution
  • 10% accuracy
  • 0.1 ppm relay, and 1 user-settable relay

The OS-6 ozone monitor is the perfect device for ozone level controls. This unit has 2 separate relays, one set to 0.1 ppm for human safety, while the other can be set for any set-point desired.

OS-6 Remote ozone monitor

https://www.oxidationtech.com/products/ozone-monitors/fixed-ozone-monitor/os6-ozone-monitor.html

S-200 handheld or remote ozone monitor

  • 0-0.5, and 0-10 ppm ranges
  • 0.001 ppm resolution
  • 10% accuracy
  • Min/Max/Average on the screen
  • Optional on-board data logging with the S-500

The S-200 ozone monitor will measure ozone as a handheld or with an optional remote sensor. Min/Max/Average ozone levels displayed on the screen along with current ozone levels.

Aeroqual Series-200 ozone monitor
S-200 Aeroqual ozone monitor

UV-106L

  • 0-100 ppm range (optional 0-1,000 or 0-10,000 ppm ranges)
  • 0.0001 ppm resolution
  • 2% accuracy

For higher ozone levels with greater accuracy the UV-106L ozone analyzer can be used to measure and control ozone levels. The UV-106L includes built-in data-logging and accuracy to within 2% of reading. With a faster warm-up period, and greater accuracy the UV-106L is a great option for portable systems or systems that require greater accuracy.

https://www.oxidationtech.com/uv106l-ozone-analyzer.html

UV-106 Ozone analyzer

Ambient ozone destruct

Ozone levels in the room can be quickly converted safely back to oxygen via an ambient ozone destruct unit. The CDA-250 is a great device for this purpose. It flows 250 CFM air through the unit and destroys at least 90% of the ozone via a catalytic material in each pass. Using this device will lower ozone levels to a safe level quickly for faster turn-around time for your ozone disinfection room or chamber.

Ambient air ozone scrubber
CDA-250 Ozone Destruct Device

Gas gas can be an effective disinfectant in the gaseous form, but must be used safely and with proper caution. Should you have questions on this application, or any details, please contact our office.

For additional information see papers at link below on this ozone application.