The Science of Ozone Laundry Systems
By Darrell Weeter
There are huge developments in the methods we use to do laundry. The largest change is the realization that we can achieve high-quality standards without using hot water or hazardous chemicals. When we think about doing laundry, we typically think of detergents, fabric softeners and hot water. The US EPA says that ingredients from detergents may contain hazardous materials, better known as VOCs. Education about the VOCs that are currently being used in detergents is important in understanding why developments in the way we do laundry are helping us go green.
Some ingredients used in a popular brand of laundry detergent that are listed (according to their public Material Safety Data Sheets) as hazardous ingredients include: Ethyl alcohol, 2-aminoethanol, anionic surfactants (alcohol ethoxysulfate, alcohol sulfates, benzene sulfonic acid), nonionic surfactants (alcohol ethoxylate). From just the laundry process, the release of some of these detergent VOCs can be off-gassed back into the air (which we then breathe) and also into our fabrics from residual detergent that remains after the wash cycle.
VOCs exposed through off-gassing into the air is a common hazard. In the 2012 Guide to Healthy Cleaning, EWG noted that products labeled fragrance-free are often scented with synthetic compounds that mask the smells of the other chemicals they contain. You won’t see these masking chemicals named on product labels either, since manufacturers generally regard them as trade secrets and are not required to list them. As a result of cleaners and other toxic household products, the US EPA reports that air inside the typical home is two to five times more polluted than the air immediately outside—and in extreme cases, 100 times more contaminated. Products that contain VOCs recommend that they should be used in well-ventilated areas, which means bringing in fresh, outdoor air to mix with indoor air. Laundry rooms are not typically well-ventilated areas and VOCs may cause severe health effects when breathed in over periods of time. Andrew Weil, MD, noted that, “We know that VOCs can cause respiratory irritation.”
Residual detergent that remains in fabrics after the wash cycle may cause other health-related concerns. Joan Tamburro, MD, of the Cleveland Clinic, stated, “There are two types of skin problems caused from detergents and other soaps left in fabrics. Irritation (a red, itchy rash) usually occurs right away, as soon as you put a piece of clothing on, for instance. Irritation goes away fairly quickly when the irritant is removed. Allergic contact dermatitis also appears as a red, itchy rash, but usually not with immediate contact. If you have a true allergy to laundry detergent or fabric softeners, you may notice redness or itching for up to a week. It can take the immune system a while to identify allergens; you can be exposed to a substance multiple times before having a response.”
It is important to talk about the health benefits of ozone use in laundry applications. It’s been found in multiple studies that ozone-oxygen mixtures at the correct levels can be used to inactivate a variety of microorganisms living not only in our clothing, but all fabrics as well. The newest technology provides major developments to avoid harmful chemicals, using ozone as a detergent-less laundry solution. As a cleaning solution, it kills microorganisms found in dirty laundry and does so approximately 3,000 times faster than bleach.
Ozone is a fantastic way to kill what we know as ‘super bugs’ such as bacteria, fungi and live viruses. It has been stated in the report, Oxidative Stress: An Essential Factor in the Pathogenesis of Gastrointestinal Mucosal Diseases, that reactive oxygen species (ROS) are natural byproducts of cellular oxidative metabolism and play important roles in the modulation of cell survival, cell death, differentiation, cell signaling and inflammation-related factor production. Ozone is considered a potent ROS that can, during half-life, cause oxidative damage to biological molecules. In the study Investigation of the mechanisms of ozone-mediated viral inactivation by Seiga Ohmine, it was found that ozone kills viruses and bacteria at extraordinary rates. His data suggested that a wide range of viruses can be inactivated through use of an innovative ozone delivery system.
It is also important to discuss how ozone can be used. Sheila Baker, PhD, Professor in the Department of Chemical Engineering at the University of Missouri-Columbia, scientifically examined the technology behind the use of ozone for detergent-less laundry solutions and in her research, covered different methods to use ozone in detergent-less laundry systems. She noted, “The method for cleaning by ozone in water is based on two reaction mechanisms: a direct and an indirect mechanism. The direct method occurs when ozone acts as the oxidizer itself to break chemical bonds. The indirect method involves ozone reacting first with water to produce OH radicals followed by the OH radicals oxidizing chemical bonds. When ozone and OH radicals come in contact with soils and stains in linen, they help break chemical bonds to release the stain or soil. One kind of reaction (direct or indirect) will dominate, depending on various factors, such as temperature, pH and chemical composition of the water. The higher the pH and temperature, the more OH radicals will be produced. While OH radicals have even greater oxidizing power than ozone, they are very short-lived in solution. We have found through testing that ozone does work for removing stains from laundry stains from laundry through an oxidation mechanism, whereby ozone and an OH radical (a breakdown product from ozone and cold water) can both work as oxidants. Ozone is considerably more effective at lower water temperatures, such as cold- or ambient-temperature water. It is an unstable molecule and heat energy causes it to break down much more rapidly. The colder the water, the more stable ozone is and the longer it lasts. Ozone solubility decreases with a rise in water temperature and other parameters, including pH, alkalinity and ozone demand by oxidizable substances that may be present. In temperatures above 95 degrees, ozone loses all of its effectiveness because heat causes it to break down and come out of solution or off-gas. At temperatures above 85 degrees, ozone half-life diminishes quickly and mass transfer is very weak.”
In 2009, a California hotel conducted an energy-savings study over a two-month period in a facility with 104 rooms, to compare traditional laundering and an ozone laundering system. They found the annual costs of ozone versus traditional laundry was less in certain categories: electrical (30%), natural gas (81%), chemical (21%), water (26%) and labor (39%) savings. A 2012 hotel study, Ozone Laundry–95 Room Hotel Payback Study, showed similar results and a savings of almost $780 per month. They found that the ozone laundry system saved over 47 percent of fuel costs for boiler and dryer operation, with a 74-percent savings for the boilers (hot water) alone. In addition, the system eliminated softener costs, reduced electrical costs for the washers and dryers by about 13 percent and reduced linen replacement costs by 10 percent.
Questions have arisen in the past about whether the ozone technologies are safe to use. The answer is yes, as the technologies have become more advanced. A perfect explanation of the common systems used was written by Mark E. Moore, a 40-year expert in institutional ozonized laundry use: “The most common ozone generator used is the corona-cell discharge type where two close-tolerance surfaces are charged with electricity (one positive and one negative). These surfaces create a high-voltage arc of electricity (lightning) between them. As oxygen flows through this arc, one to 10 percent of the oxygen is converted into ozone.”
“The most common injection method is by Venturi injection, where the applied water pressure passes through a narrow throat that constricts the flow of water (this increases the water velocity and decreases the pressure of the water passing through it), creating a partial vacuum to an atmospheric connection port immediately after the constriction. This vacuum is what permits the ozone transfer to the water, thereby creating the mass transfer mentioned previously. When applied to this suction port, 85 to 90 percent of the ozone gas is instantly dissolved into the water. This makes Venturi injection a much more reliable and stable way to dissolve ozone into water. The disadvantage of the Venturi injection is that it costs more to build this type of system. A Venturi injection system instantly fills the washer with highly concentrated ozonated water that instantly starts the cleaning and sanitizing process. Finally, some Venturi injection systems on the market allow for larger than normal fill valves and water lines to be utilized. This will allow for much faster fill times.”
There are a lot of engineering mechanics inside of these products. An expert in measuring ozone levels for safety from Oxidation Technology stated that these types of units should be all stainless steel, especially around the corona cell, to prevent rust. All units should have parts that are compatible with ozone to prevent acidic build up throughout the machines, which can destroy the circuit board and other electronics in the unit. These units should assure ozone injection with some type of vacuum-like suction to pull the ozone from the corona cell to the injector, to ensure the product will work as intended. There should also be some type of dryer to keep humidity out of the unit. Most machines rely on the corona cell and if/when the spark gap gets too damp from humidity, there’s less of an arc, which reduces how much ozone is being produced. Additionally, an Ozotech expert noted that ozone in these systems should be injected at a rate where the ozone is being mixed into the water at a rate that meets or exceeds the requirements set forth by the Food and Drug Administration (FDA) and US EPA, for disinfection purposes.
Overall, ozone as a detergent-less laundry system can be compared to electricity. When electricity first emerged as a power source, people were afraid of it. With use, there should be forms of control. Be sure to use a high-quality product, backed up with a good warranty and excellent customer service. We are still studying ozone but the pros outweigh the cons and the technology is advancing more each day. It is definitely a new, exciting business to be in. The technology is a huge development for achieving green standards.
- US EPA. Volatile Organic Compounds. https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality. Accessed July 2017.
- Material Safety Data Sheet. https://sites.ewu.edu/centralstores/files/2017/01/Liquid-2X-Tide-Products-MSDS-updated-04-08-2015.pdf. The Procter & Gamble Company. April 2015. Accessed July 2017.
- Andrew Weil, M. Scented Detergents are Harmful. https://www.drweil.com/health-wellness/balanced-living/healthy-home/are-unscented-detergents-harmful/. Accessed July 2017.
- Tamburro, Joan, DO. Is Laundry Detergent Causing Your Child’s Skin Rash? https://health.clevelandclinic.org/2014/12/is-laundry-detergent-causing-your-childs-skin-rash/. December 2014.
- Environmental Working Group. Cleaning Supplies and Your Health. www.ewg.org/guides/cleaners/content/cleaners_and_health#.WWkrsojyuUk. Accessed July 2017.
- Ohmine, Seiga. “Investigation of the mechanisms of ozone-mediated viral inactivation.” 2010.
Sheila Baker, M.D. The Science. n.d. www.Oxidizeit.com. Accessed July 2017.
- Rice, Rip; DeBrum, Marc; Cardis, Dick and Tapp, Cameron. “Microbiological Benefits of Ozone in Laundering Systems.” Ozone: Science & Engineering (2009).
- Moore, Mark E. Benefits of Venturi Injection Versus Diffuser. n.d. www.absoluteozone.com/benefits-of-using-venturi-injection-over-diffuser-in-commercial-ozone-laundry.html. Accessed July 2017.
About the author
Darrell Weeter is Owner, President and CEO of OXIDIZER PRO and Filtropur subsidiaries of FVS INC., which he opened in 1986. In 2015, he became interested in water technologies when he sampled different products in the water industry. As a result, Weeter invested in ozone technology and assets.
About the company
Oxidizer PRO INC., is an American company located in Broadview Heights, OH. The company combines aggressive strategic marketing with quality products and services at competitive prices to provide the best products for its consumers. They will realize this mission by setting the highest standards in service and reliability within the industry.
About the product
The Oxidize-IT product has been improved and continues to grow with the latest and greatest technologies available. It is the first of its kind, in which the company can provide technologies inside the machine, such as: an air dryer, a vacuum switch that insures 03 injections and a stainless-steel corona cell. The system is designed in such a way as to guarantee a longer product life with a five-year warranty.