Noroviruses are the major etiological agent of gastroenteritis in all age groups worldwide and are transmitted via fecal-oral route. As important waterborne and food-borne pathogens, they are included on the U.S. EPA Contaminant . Water can be contaminated by Norovirus containing feces released from either symptomatic or asymptomatic patients. Noroviruses have been linked to many waterborne disease outbreaks in the U.S. They have been detected in sewage effluent and in ambient water .
Noroviruses cause a gastroenteritis, which usually lasts 24 to 48 hours. Symptoms include vomiting, abdominal cramps, and diarrhea.
Owing to its high effectiveness of ozone as a strong oxidant and lack of residue after disinfection, ozone can be used for both surface and groundwater disinfection. Several studies have proven ozone effectiveness on removing the Norovirus. It has been shown that ozone eradicates the Norovirus.
More than 99% of the Norovirus can be inactivated by ozone at 1 mg/liter within 2 min .
. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Feb. 2010, p. 1120–1124, accessed August 2015.
. Parshionikar, S.U., S. Willian-True, G.S. Fout, D.E. Robbins, S.A. Seys, J.D. Cassady, and R. Harris. “ Waterborne outbreak of gasteroenteritis associated with a norovirus”, Applied and Environmental Microbiology. 69(9):5263-5268, 2003.
. Mi Young Lim, Ju-Mi Kim, Jung Eun Lee, and GwangPyo Ko, “Characterization of Ozone Disinfection of Murine Norovirus”, APPLIED AND ENVIRONMENTAL MICROBIOLOGY, , p. 1120–1124, 2010.
Metropolitan Board Authorizes Ozone Retrofit at District’s Oldest Water Treatment Plant
F.E. Weymouth plant in La Verne is final treatment facility to receive ozone upgrade
The Metropolitan Board of Directors today authorized construction of $140.4 million of new ozone facilities at the district’s oldest treatment plant, a project that will help boost the regional and state’s economy, add up to 1,200 jobs during construction while enhancing Southern California’s drinking water quality.
The new facilities will use ozone to replace chlorine as the primary disinfectant at Metropolitan’s F.E. Weymouth Water Treatment Plant in La Verne.
“One of Metropolitan’s primary responsibilities is to provide high-quality water within its six-county service area and to fully meet current and future drinking water quality standards,” said Metropolitan board Chairman John V. Foley. “Nearly 20 years ago, we identified ozone disinfection as a more effective treatment process. Today’s action is another significant step in our comprehensive plan to convert all five Metropolitan treatment plants to ozone technology.”
Metropolitan General Manager Jeffrey Kightlinger called ozone treatment the most beneficial and cost-effective way to improve and protect the quality of drinking water served to 19 million Southern Californians.
There have been a lot of question about the efficacy of ozone in warm/hot water. Yes – ozone does work in hot water! See the supporting documentation below.
Ozone Efficacy in Hot Water – PDF
EPA Chart showing log 4 virus inactivation with ozone vs. temperature
R.N. Kinman (1975) & E. Katzenelson, et al. (1974) reported “As temperature increases, ozone becomes less soluble and less stable in water; however, the disinfection and chemical oxidation rates remain relatively stable. Studies have shown that although increasing the temperature from 0 to 30 deg C can significantly reduce the solubility of ozone and increases its decomposition rate, temperature has virtually no effect on the disinfection rate of bacteria.”
In other words, the disinfection rate was found to be relatively independent of temperature despite the reduction in solubility and reduced stability at higher temperatures.
If hot water reduces the solubility of ozone, how is Ozone Solutions addressing the lower solubility issue?
Generating high ozone gas concentrations provides better ozone mass transfer into water. We generate these high concentrations by:
using an oxygen concentrator to provide a 90% pure oxygen feed gas to the corona cell thereby increasing the generated ozone concentration
A popular page on the Ozone Solutions webpage is the ozone properties page. Recently the Ozone Solubility chart on this page was expanded. The chart below shows what we now have on our website. This data replaces the old chart with only 9 data points that were a little more difficult to understand due to the units used.
This new chart shows the huge difference in ozone solubility based on water temperature and ozone concentration. This data is very helpful when designing a new ozone water treatment system, or troubleshooting existing ozone systems. This data shows that if your water temperature increases the resulting dissolved ozone level may change dramatically. Or, if ozone is generated at only a slightly lower concentration dissolved ozone levels will be dramatically lower.
The solubility of ozone depends on the water temperature and the ozone concentration in the gas phase: Units in g/m3.
Iron and manganese removal is one of the more common uses for ozone in drinking water systems. Iron and manganese are easily oxidized by ozone. This document will serve to help understand the fundamentals of iron and manganese oxidation with ozone. We will also cover the practical application of ozone in this application while offering helpful tips learned over the years.
Ozone oxidation of iron and manganese is an extremely fast reaction. In many ozone applications elevated levels of iron and manganese can cause nuisance issues due to soluble iron and manganese inadvertently oxidizing by ozone and dropping out of solution in less than ideal locations. If those concerns are what brought you here, keep reading, we will offer helpful tips to mitigate these issues as best as possible.
Iron and manganese in water cause no health related issues, the main purpose for iron and manganese removal is aesthetics due to the discoloration of water. Removal also may be necessary due to buildup of iron and manganese on pipes, fixtures, and other surfaces.
Both Iron Fe(II) and Manganese Mn(II) are soluble (non-removable) in water causing them to flow directly through conventional filtration without some form of oxidation to transform them into particulates (removable).
Soluble Iron Fe(II) is called ferrous iron. Ferrous Iron Fe(II) is oxidized to Ferric Iron Fe(III) by ozone. This Ferric Iron Fe(III) will then hydrolyze to form Fe(OH)3 which is a particulate and can be removed by standard filtration. The reaction of Ferrous Iron Fe(II) to Ferric Iron Fe(II) consumes 0.43 mg of ozone per mg of Fe(II). Iron can also be oxidized by oxygen. Due to the oxidation of iron by oxygen, an Ozone System for iron removal may be more efficient that the calculated ozone demand of 0.43 mg ozone per mg iron. The oxidation of ferrous iron requires only an electron exchange and therefore is a fast reaction. The speed of this reaction will typically consume almost all ozone in iron oxidation reaction prior to any manganese oxidation.
Soluble Manganese Mn(II) is oxidized by ozone to form manganese dioxide MnO2 which is a particulate and can be easily removed by standard filtration. This process consumes 0.88 mg of ozone per mg of Manganese Mn(II). However, over oxidation of manganese will form soluble permanganate MnO4-. While permanganate will normally return to manganese dioxide MnO2 over time (20-30 minutes) it is best to design a manganese removal system with the proper ozone dosages and integrate controls to prevent over oxidation.
Ozone will oxidize iron and manganese to form insoluble particulates that can easily be filtered from the water. Iron and manganese will build up on the filter over time and must be removed from the process water. A back-washable filter is highly recommended for these applications. Sand filters are widely used for iron and manganese removal due to the simple design and the long lasting filter media. In continuous use systems it will be necessary to use two (2) filters in parallel and time the back-wash cycles to occur at opposite times.
The back-wash water from these filters will have extremely high levels of iron and manganese and must be disposed of with care. While neither iron or manganese have any health or safety risks, there are plumbing considerations to keep in mind as drain pipes may become obstructed with iron and manganese build-up over time.
The use of ozone for iron and manganese removal is very common and has been in use for many years. The reaction of ozone and these metals is fairly simple and straight forward. There are a few design considerations that should be accounted for prior to installing an Ozone System for iron and manganese removal.
Sizing an Ozone System for iron and manganese removal can be fairly straight forward. Basic ozone demand must be calculated to determine how much ozone is necessary to oxidize both iron and manganese. Keep in mind that all other elements in the water may react with ozone and consume some ozone. Other potential reactions must be accounted for and entered into the calculations. For simplicity we will assume only iron and manganese are in our sample water.
The stoichiometric ozone demand rates were covered in the chemistry section of this document. They are 0.43 mg for iron and 0.88 mg for manganese.
Ozone dosage into water is calculated using the following formula:
(3.78 * 60 * GPM * PPM) / 1000 = g/hr
If for example incoming water of 10 gallons per minutes (GPM) has 3 ppm of iron and 0.5 ppm manganese the following calculations would be used
This calculation provides the necessary ozone in grams per hour (g/hr) to oxidize the iron and manganese. Additional ozone production may be necessary to overcome system inefficiencies, water temperature, or other factors. (This is for demonstration purposes only.)
Due to the fast reaction of ozone and iron oxidation there are some important design considerations that must be evaluated prior to system implementation. For an example of a working system design review the diagram below.
Clean, filtered water is used for ozone injection. Due to the fast reaction of ozone and iron it is common for ozone injectors, pumps, and other piping to become obstructed due to iron build-up. Using clean water for the ozone injection loop eliminates this potential.
Aqueous ozone is mixed with the incoming water in a contact tank to allow the reaction of iron and manganese to occur in a tank that will off-gas all excess ozone safely.
Redundant sand filters are used to filter the oxidized iron and manganese from the water stream.
ORP meters or dissolved ozone meters can be used to automate the Ozone System. These probes must be placed in the clean water stream to eliminate fouling.
Ozone use for iron and manganese oxidation can be a great solution to what may have been a difficult problem to solve using other technologies. Ozone can be implemented very easily and reliably with no major maintenance or operation costs. However, ozone can also be difficult to manage if not installed properly. Iron can precipitate from solution in undesirable locations, and manganese can be over-oxidized and pass through filtration even after ozone treatment. This informational document serves to offer some helpful tips and useful information. If you think ozone may be a solution for your application give our office a call and speak with one of our Application Engineers to help design a solution that is right for you.
Ozone is increasingly used in aquaculture due to its numerous advantages over traditional water treatment methods. Supplementing or replacing an existing system, ozone implementation has the potential to boost the competitive advantage of your aquaculture application.
The Flash Reactor manufactured by Mazzei Injector Company is yet another great tool to dissolving ozone gas into water. This product has been in production for a few years now. I wanted to take the time explain a little about where these might be used in an ozone injection system.
Typically a Flash Reactor would be used in conjunction with an Ozone Injector. The Flash Reactor can be placed in line after the ozone injector to aid in mass transfer of ozone into the water. Following is the description of the Flash Reactor from the Mazzei website.
The patented Mazzei® Flash Reactor™ is a uniquely innovative mixing chamber that incorporates a re-directional and shearing design of the gas/liquid water mixture that allows for a rapid dissolution and attainment of gas/liquid equilibrium. The result is high mass transfer efficiency with minimal time required.
Research done on the flash reactor and ozone injector was performed by the Civil and Environmental Engineering Department, 3-093 Markin/CNRL Natural Resources Engineering Facility, University of Alberta, Edmonton, Canada. This research abstract can be viewed HERE at the Mazzei Website.
A great use of the flash reactor is when ozone injected into water with an ozone injector at low pressures and improved mass transfer of ozone is desired. Many systems can benefit from the addition of a Flash Reactor into the system to improve mass transfer of ozone without any other modifications of the system.
A few of our rental ozone injection systems have been added to our website, and are officially available for rental. We now rent 2 new ozone injection systems mounted inside weather tight enclosures. These systems can be placed in harsh plant environments, or the elements of the outdoors if necessary. This offers a greater amount of flexibility for you, the user.
These systems both require only compressed air and electrical power for operation. No other utilities are required. With simple installation and durable construction these make a great pilot, or temporary ozone injection system for many applications. For questions contact our application engineers today.
Ozone has many applications. One of these applications is a biocide in cooling towers. Cooling towers recirculate the same water over and over again within a mostly closed loop system. This water must have chemical treatment to maintain clean water with no bacteria or algae growth. Ozone can replace traditional chemicals and offer a green solution to this application.
We have recently completed an installation of a 300 g/hr ozone generation system into a large cooling tower at an ethanol plant. The use of ozone will replace chlorine and bi-sulfate chemical additions. Using ozone will eliminate the need to transport, store, and purchase bulk chemicals.
The ozone system produces ozone from a 300 g/hr water cooled ozone generator. This will produce 300 g/hr of ozone from 40 LPM of oxygen at 9% by weight from oxygen. Oxygen is provided by an Air-Sep AS-D oxygen concentrator using compressed air to provide 40 LPM of oxygen feed gas for the ozone generator. The AS-D is fed with compressed air supplied by the customers current compressed air systems.
Ozone is injected directly into a water recirculation line using a custom ozone injection point. The picture below shows the ozone gas plumbed into this injection point. This injection point will diffuse the ozone into the pipe via micro bubbles. This pipe recirculates ~300 gpm of water, this water travels 150 yards then discharges into the cooling tower basin. This pipe distance allows the ozone to achieve excellent mass transfer efficiency.
Currently this ozone system is rented by the customer with the option to purchase at any time. This offers great flexibility for the customer, and cost savings over the previous chemical additions. For information on our ozone solutions for your application contact us today.
This Ozone Journal is a blog managed by the employees of Ozone Solutions. The purpose of this blog is to inform and educate the readers about the world of Ozone, provide news about the ozone industry, and have an easy opportunity to inform about new ozone products.
Check back often, ask questions, and let us know if there is anything you would like to hear about.
What is ozone?
Ozone is an oxidant. Ozone (O3), sometimes called “activated oxygen", or "triatomic oxygen", contains three atoms of oxygen rather than the two atoms we normally breathe. Ozone is the second most powerful oxidant in the world and can be used to destroy bacteria, viruses, and odors.
Ozone is a gas at ambient temperatures and pressures with a strong odor. Ozone can be produced as a gas from oxygen in air, or concentrated oxygen. This ozone gas can be dissolved into water, or used in the gas phase for a variety of applications discussed in this Journal.