E-Coli Summary

E.coli Reduction with Ozone

The most common topic for discussion around workplace water coolers is not bacteria. However, there is a certain strain of bacteria that has generated a good amount of press and discussion. The strain of bacteria, E. coli O157:H7 has become popular in the media, which has caused many people to have a healthy fear of this bacteria.

Escherichia coli (E. coli) is a strain of bacteria that is commonly found in the intestines of animals and humans, and are known to be dangerous and can cause food borne illnesses. The strain of bacteria, E. coli O157:H7, can be life threatening and has resulted in an estimated 2,100 hospitalizations, and is one of the most dangerous strains of E. coli.

Many vegetables, meats and even water supply can contain this strain of E. coli. The biggest cause of infections from E. coli are from food borne illnesses like under cooked ground beef. However, some waterborne illnesses have been found as well. The Canadian town of Walkerton, Ontario had a municipal water supply contaminated by this strain of E. coli in May of 2000. As a result, the pathogen has been blamed for over 2,000 illnesses and 7 deaths.

Solutions to reduce food borne pathogens are becoming very rare. For example, in the past, chlorine has been widely used as a cheap and effective oxidizer to kill a variety of pathogens. However, chlorine is being used less and less as the side effects of the chemical are slowly becoming more apparent. Other chemicals such as methyl bromide, chlorine dioxide, and sodium hypochlorite, that have been used to combat pathogens in the past are also being used less because of the awareness of side-effects.

Ozone is found to be a new and effective method of antimicrobial intervention. In certain industries, such as drinking water, food processing, and surface sanitation, ozone is becoming very popular. Ozone has been proven to be an effective disinfectant against many different pathogens, but studies needed to be conducted in order to prove it was useful against this particular strain of E. coli O157:H7. After research was conducted, it was proven that ozone is effective against this strain of E. coli.

Below is an excerpt from the Direct food additive Petition presented to the FDA in August 2000 to achieve GRAS status for the use of ozone to inactivate E. coli O157:H7, along with other pathogens.

Implementation of Ozone

Aqueous Ozone

The most common method of using ozone for pathogen reduction is dissolving ozone into water. Aqueous ozone is very stable, safe, and easy to manage. Typically, ozone is dissolved into water using an ozone injection system, and then sprayed onto the surface requiring disinfection. This surface may be a hard equipment surface, or the surface of a food product.

Ozone levels of 2.0 ppm are commonly used for E. coli O157:H7 reduction. Only a few seconds of contact time of the aqueous ozone with the pathogen is necessary for inactivation. See chart below.

Using this data, a determination of spray nozzles, spray bars, or even conveyers can be established. It is clearly shown that 2.0 ppm of aqueous ozone is very effective in only a short period of time, while higher ozone levels show only marginal improvement.

Ozone can be used in drinking water to inactivate E. coli O157:H7. This has been confirmed by the EPA and recognized as a suitable disinfectant for water.

Gaseous Ozone

The use of gaseous ozone for the elimination of pathogens is less common. There is also less research showing the effects of gaseous ozone on bacteria. The application of gaseous ozone is dependent upon the temperature, humidity, contact time, and ozone levels. Research has been conducted to determine that gaseous ozone will reduce and inactivate E. coli O157:H7, however more research is necessary to determine the effectiveness of ozone within different variables.

Corona vs. UV Ozone

Many users of ozone are made to believe that it will help in every scenario. Ozone chemistry is often totally ignored. UV Ozone, in India, is often recommended for water disinfection, when in reality, ozone offers no benefits in water treatment. Benefits, not the cost, should be the only criteria for selection.

Ozone is a very good disinfectant and many people know it by that. However, the benefits and effectiveness of ozone will depend on the method of ozone generation.

Primarily, there are two ways of producing ozone:

-Ozone using UV lamps

-Ozone by the Corona discharge method

Role of Ozonation

The purpose of ozone is both to perform oxidation, as well as disinfection (oxidation to remove organic and inorganic contaminants, and disinfection to kill bacteria, etc).

Regardless of how much ozone is generated per hour, a minimum concentration of at least 1% is required for both oxidation and disinfection. UV ozone generators cannot perform oxidation and disinfection at the same time at this concentration.

Concentration of Ozone

CD ozone generators can produce ozone at a concentration ranging from 1-16% w/w, compared to 0.1-0.001% w/w by UV ozone. This means that CD ozone generators can produce at concentration from 10 to 1000 times higher than that of UV ozone. The amount of air needed for UV ozone generators is 10 times more than what is needed for a CD ozone generator.

UV Lamps Used

A majority of UV ozone generators will use 454 manometers (nm) radiation. 89% of relative spectral energy of UV lamps are at 254 nm, and low of 218 nm. The maximum production of UV ozone happens at 260-265 nm. Therefore, by using 254 nm UV bulbs, it is impossible to produce more than just traces of ozone.

Mechanism of Action

That is the most important difference between UV ozone generation and CD ozone generation. Ozone generated by UV ozone is immediately decomposed by the UV radiation, which then forms free hydroxyl radicals. In aqueous ozone solutions, these free radicals (OH+) can be very powerful oxidizing agents. However, the disadvantage to these free radicals is that their half-life is around microseconds, and compared to 22 minutes of ozone. Because of this, ozone that is generated by the UV method, cannot be expected to remain in the solution for a sufficient period of time that allows adequate disinfection, even though chemical oxidation can occur.

Recently, UV ozone has started using 172 nm bulbs. These bulbs produce a higher concentration of ozone, but the bulbs themselves have not been commercially available or tested yet.

Why Concentration of Ozone is Significant?

There is only a partial solubility of ozone in water that is governed by Henry’s Law (the solubility of the gas in water is directly proportional to its partial pressure in the gas phase). Because of Henry’s Law, the higher the ozone concentration means the greater the solubility into water. The more ozone that is dissolved into water, the more effective it can be as a disinfectant. Through research and studies, it is clear that through UV radiation, there is not much ozone available in the water for both oxidation and disinfection.

Chicks Law Factor

The process in which ozone disinfects is governed by Chick’s Law. This law follows the Contact Time factor. For each strain of bacteria/virus, ozone has different contact times needed to kill that strain. Contact time needs to be controlled or maintained in order for the full benefits of ozone disinfecting to work. Just like antibiotics, each particular antibiotic needs a certain amount of time for it to work effectively. For ozone disinfecting to work, there needs to be enough contact time for it to do its job properly. The most important factors in ozone disinfection are concentration and time, both are not achievable with UV ozone generation.

Ozone can more easily destroy air-borne bacteria and viruses rather than water borne organisms. That is why the ozone requirement for air treatment is so low. That is another reason that UV ozone is only used in air treatment – high concentrations of ozone are not required for disinfecting. Ozone only has to spread in the air in order to work effectively, whereas in water ozone needs to first be dissolved in order to work.

To view all of our ozone generators, please click here.

Cooling Tower Water Ozonation: Ozone Wonder

Cooling towers use a large amount of toxic chemicals in order to keep the cooling water clean, protecting the cooling towers. Blow down water is discharged to keep the cooling tower safe, and before each discharge the water needs to be treated and cleaned. Environmentalists are putting pressure on officials to make a change.

There has been a wide acceptance of the use of ozone technology around the globe, however, the use of ozone in India has been under question because of the lack of quantified studies and references. OTSIL and WEDECO have undergone some very extensive studies with the use of ozone in cooling towers over the past 5 years, and have quantified the benefits that go with it for the first time.

The use of ozone provides the following benefits in a nutshell:

  • Completely eliminates Biocides, making the discharge water cleaner.
  • More than reduces 90% of Sulphuric acids and de-scalents for large towers.
  • No hazardous chemical storage and Handling such as gas chlorine.
  • Enables the CT (contact time) to be operated at Higher COC (cycle of concentration), eliminates controlled blow down.
  • Prevents scaling, corrosion and reduces algal growth.
  • Saves energy in operation of the Cooling tower.
  • Finally Saves water, saves chemicals costs, allows the power plant comply with environmental needs and make them environmentally friendly.

The same quality of MUW allows the cooling tower to more than double the COC of chemically treated tower, while using ozone.

Studies have shown that there is a buildup (0.1 in) of calcium carbonate scale on the heat exchanger surface that reduces the heat transfer by as much as 40%. The energy savings happen because virtually limited scaling is noted with ozone treatment, and reduction in scale thickness also improves heat transfer efficiency of an ozonated cooling tower, saving power. The power savings is anticipated to be around or above 10%.

Make up water quality is the most important criteria that influences the performance of the cooling tower. If it is good quality, then ozone can be introduced directly into the CT tower basin. By using ozone, you can ensure that the tower water will be very good quality. Ozone is able to remove many dissolved organics in the water, including the ones responsible for odor and color. The presence of organic matter in cooling towers will contaminate the entire cooling tower loop including the condenser, and could be the main reason bio fouling that induces scaling and corrosion. The presence of other bacteria’s as well, including the SRB bacteria, would also increase anaerobic reactions within the tower. It is an accepted fact that ozone in MUW and side stream filtration in a cooling tower can solve more than 60% of problems that cooling tower operators face.

Product Spotlight: Used Ozone Products

The Perfect Combination of Variety and Discounted Prices

With the large volume of products we have coming in, it is a good time to spotlight the used products that we have in stock. The used products are in excellent condition, and are still being offered at a great discount. All used products that come back to us are re-inspected, ensuring that you are getting a like-new product that runs as if it were just being taking out of the box. Used products are listed for sale, but they can also be rented out if you looking for Ozone equipment that would just be used for a temporary period of time. All items sold also come with a warranty. Whether it’s an Ozone Generator, Monitor, System, or Oxygen Concentrator, we have the used products you need, at a great discounted price.

We have a wide variety of Used Ozone Generators in different sizes for sale. If cannot find the used generator that you were looking for, just contact our office and we be happy find an alternative option that can fulfill your needs. When it comes to Used Ozone Monitors, we always have units that are in testing or calibration that have not been posted on the website yet. From units like the Q45H/64 Ozone Transmitter, to the D16 Ozone Monitor, the wide variety ensures that you will be able to find the used monitor you need at a fraction of the typical sale price. Much like the Ozone monitors and generators, the Ozone systems and Oxygen concentrators variety and pricing is sure to give you the best bang for your buck.

Once again, all used products have been re-tested and are sold with warranty to maximize piece of mind that you are getting a product in perfect running condition.

If you are looking for a used product that isn’t on the website, please contact us and we’ll find the best product for you.

To view all of our used Ozone Products, please click here.

Air Preparation for Ozone Generation

For ozone to be produced from ambient air, it requires the air to be prepared and made suitable for production. Air contains gases including nitrogen and oxygen, apart from particles of dust, moisture, and small amounts of oil accumulated from the compressor used. Dry and prepared air keeps ozone equipment running at peak efficiency and will also extend the service life of the dielectric cells. Dry air will help ensure everything is quality throughout the process. Since the oxygen in the air is converted to ozone through electric discharge (high voltage), impurities in the air will interfere with ozone production, and could even produce unwanted chemical reactions that can be detrimental to the equipment used.

Moisture – Where Does it Come From?

Atmospheric air will always contain moisture, or water vapor.  A significant drop or increase in temperature will cause moisture to condense out of the air. Saturation point is the point where air is holding all the water vapor it possibly can (100% relative humidity). If more water vapor is added to the saturated air, all of the water vapor would condense into a liquid. Condensation is the changing of water vapor into a liquid. The dew point is the temperature where water vapor would condense into a liquid.

What are the Effects of Moisture and Contaminants on Ozone Production?

Any contaminants in compressed air will negatively affect all components of the air distribution system, as well as the ozone cells themselves. Water vapor and any other contaminants in the ambient air will enter the compressor intake. The air contains Nitrogen, and as ozone is formed in the equipment, the presence of moisture will complete the chemical reaction that forms nitrous oxide with oxidation, proceeding fully into Nitrous and Nitric acids. These acids are very corrosive and tend to corrode all parts of the ozone generator, which reduces the effective life of the equipment as well as increases the maintenance cost. If dust is present, it could cause sparks and inconsistent corona, which in turn reduces the ozone production as well as producing what are known as pin holes in the glass di-electric, over time. This will result in the failure of equipment. Additionally, if ozone is used in water and air treatment, the presence of these acids could be expected to be in the water and the air which is not advisable.

How are Moisture and Contaminants Removed?

After-coolers are a good firs step. The compressed air is lowered to a safe, usable level and remove up to 70% of the water vapor, yet the water is still saturated. A further drop in temperature cases an additional condensation to occur in the downstream air lines. The air dryers remove the water vapor and lower the dew point temperature of the compressed air. This will prevent liquid water from forming downstream, but it does not eliminate all of the entrained contaminants. Filters and separators then remove the liquid water, and solid and gas contaminants that will adversely affect the air system. Drains discharge the accumulated water and liquid contaminants from the various points through the system.

How Do I Select the Right Air Dryer?

Considered these factors when determining the most cost-effective, compressed air-drying system that is suitable for the application. The varying factors are their dew point, initial cost, and ongoing maintenance requirements.

Point to Remember

-Choose a dew point temperature below the lowest ambient temperature to which your compressed air system will be exposed.

-Determine which dryers will produce the required dew point. 

-Consider initial and operating costs. The lower the dew point, the more expensive the dryer is to purchase and operate but the More the ozone is produced.

Calculations: Air vs. Oxygen as Feed Gas for Generating Ozone

Ozone Generation: Air Feed

Air is one method for ozone generation. The ozone concentrations achieved by using air as the feed gas are low. The maximum concentration achievable with the best technology is 5%. The effectiveness of the ozone however, is not in anyway inferior to the effectiveness of ozone produced with oxygen as the feed gas.

The process requirement is what determines whether you should use air or oxygen as the feed gas. The rule of thumb is: the larger the volume of water, the more volume of gas is required and therefor air is most suitable. E.G. municipal water ozonation. The lower the volume of water, the better it is to use oxygen as feed gas. E.G. waste water treatment.

The effectiveness of ozone is governed by Henrys law, Chicks law, etc., in most cases. Air only contains 21% oxygen and requires 4 times the volume of air to generate the same quantity of ozone as oxygen being the feed gas. For large requirements of ozone, like for industrial applications such as effluent treatment, processing etc., ozone is best produced with oxygen. The total costs of ozone generation for large doses of ozone will be much lower for ozone produced with air instead of oxygen. For smaller requirements of ozone, production with air will be more economical than with oxygen.

Calculations

Molecular weight of air: 1293 (1 m3 of air weighs 1293 grams) Air Feed 1% ozone concentration: 1293 x 1/100 = 12.96 g/m3 of air 2% ozone concentration: 1293 X 2/100 = 25.86 g/m3 of air 3% ozone concentration: 1293 x 3/100 = 38.79 g/m3 of air 4% ozone concentration: 1293 x 4/100 = 51.72 g/m3 of air 5% ozone concentration: 1293 x 5/100 = 64.64 g/m3 of air

Oxygen Feed

It may be better to use oxygen as feed gas in areas that water quantities are low. That way the gas quantity will be low and easily manageable, the high concentration are likely to increase ozone dissolution, per Henrys law.

Molecular weight of oxygen: 1428 (1 m3 of oxygen weighs 1428 grams)

Oxygen Feed

6% ozone concentration: 1428 x 6/100 = 74.88 g/Nm3 of O2

7% ozone concentration: 1428 x 7/100 = 99.96 g/Nm3 of O2

8% ozone concentration: 1428 x 8/100 = 114.24 g/Nm3 of O2

9% ozone concentration: 1428 x 9/100 = 128.52 g/Nm3 of O2

10% ozone concentration: 1428 x 10/100 = 142.80 g/Nm3 of O2

11% ozone concentration: 1428 x 11/100 = 157.08 g/Nm3 of O2

12% ozone concentration: 1428 x 12/100 = 171.36 g/Nm3 of O2

It is very difficult to economically produce 13% concentration and beyond. Since the higher the concentration the power is consumed and at 13% this becomes disproportional to be economically viable.

The converse calculations will be used to determine the quantity of air/oxygen required to produce ozone at a predetermined concentration of ozone.

Let us assume that you want to produce ozone say 2000 grams of ozone at 8% concentration with oxygen as feed gas. Then the quantity of oxygen required will be: (2000/0.08) / molecular weight of oxygen: i.e. = (2000/0.08)/1428 = 17.5 m3 of oxygen /hour. You will than design the oxygen plant accordingly. Of course, you will adjust the quantity based on the purity of oxygen and atmospheric pressure.

Please follow these links to browse our collection of Ozone Generators and Oxygen Concentrators.

Product Spotlight: Ozone Accessories

To match our vast product line of systems, concentrators, and generators, here at Oxidation Technologies, we also offer a wide array of Ozone accessories. The often low-priced and extremely usable Ozone accessories will help ensure that you are able to get your Ozone systems back up-and-running as soon and as easy as possible. Whether it’s the tubing, check valves, diffusers, or one of our many other Ozone accessories, we have all the products you need to make sure your Ozone systems are always running at peak performance.

Fittings

With over 80 options, we are sure that you will be able to find the Kynar Fitting that you are looking for. The fittings are made out of PVDF (polyvinylidene fluoride), a thermoplastic material that is compatible with Ozone. Creating these fittings from PVDF makes a fitting that is resistant to abrasion, as well as chemical corrosion, the result is a fitting that is perfect for situations containing corrosive fluids. They are also equipped with a plastic gripper nut, guaranteeing that you will get an incredibly tight grip on plastic tubing every time.

Tubing

FEP (Fluorinated ethylene-propylene) Tubing is the best tubing on the market when it comes to working with Ozone. FEP tubing is 100% Ozone resistant, capable of working with very high temperatures, and it is also made with maximum flexibility in mind. FEP tubing is what we using when building our own Ozone systems, so it is always in stock at our warehouse and can typically ship in any length you would like. If you prefer a specific coil length or spool, please call or e-mail us and we’ll be happy to accommodate.

Ozone Diffusers

Ozone Diffusers are just another one of the great Ozone accessories that we offer, and when it comes to diffusers, nothing compares to the SS6-12 Diffuser. The SS6 has a 20-micron rating and is capable of bubbling ozone into water at flow rates up to 5 CFM. The SS6 creates bubbles at both low and high-rates so there is absolutely no compromise on the mass transfer at any flow-rate. The SS6 is great for treating wastewater, groundwater remediation, and many other applications. Click here to see our other Diffuser options.

And Even More

It is also important to note impressive products such as our Venturi Injectors, and our Check Valves. Our Venturi injectors are created with a Black Kynar material that promises longevity because of its optimal ozone resistance. We offer a wide array of injectors that work with almost any flow rate so you will be able to find the right product that works for you. The injector is perfect for ozonating a continual stream of water. Our check valves work with the injectors so you are left with a connection that is leak-proof and durable.

To see all of our Ozone Accessories, please click here.

60 g/hr Ozone Generator for rent

60 g/hr Ozone Generator for Rent

Oxidation Technologies is now offering a rental Ozone Generator that is capable of efficiently producing 60 g/hr of Ozone. This product can operate well on both 50 hz or 60 hz of power with no changes or alterations needed. This generator also has an adjustable output standard. The 60 g/hr generator is incredibly easy to install and operate. It also comes in a plastic enclosure, making it incredibly durable.

If you are looking to purchase an Ozone Generator with similar performance specifications, we highly recommend checking out either the OXG-60, or the OXP-60 Ozone Generators.

All other Ozone Generators from Oxidation Technologies can be found on our website following this link.

Oxidation Tech Rental Terms

-Pre-payment required for all rentals – payment can be made online with credit card

-Shipping both to/from is paid by the customer – ground shipping is alright

-Equipment is guaranteed to come in working order, damage to equipment will be billed

-Terms of the rental can be extended at any time throughout the duration of the rental

-There are discount for longer rental terms, arrangements have to be made pre-purchase

More information/purchasing options regarding the 60 g/hr Ozone Generator Rental can be found here.