DEL Ozone Disinfection is Tested and True
How do you measure ozone’s performance? Ozone is undetectable by human senses when properly dissolved in water the way it is with well-engineered systems like DEL’s. How do you measure it?
DEL Ozone does not simply assert the power of ozone – we test and verify it. Our customers and their clients depend on ozone sanitation or disinfection where effectiveness is critical. We seek and use objective information.
DEL continuously tests its own equipment for reliability, effectiveness and safety, but it also engages accepted third-party test agencies such as NSF, UL,and assorted accredited independent testing labs to perform objective critical testing against government and/or industry standards. Our claims for health and safety protection are based on these tests, not chemical theories or wishful thinking.
Below is a sample of the tests we have commissioned over the past 25 years, and you can link out to PDFs to see the information directly (warning: these are scientific documents and may be a lengthy read). Other tests are taking place on a continuous basis, and will be added to this page in the future.
3rd Party Tests and Validations of DEL Ozone Systems Disinfection Performance
Ozone Disinfection of Cryptosporidium parvum
With the rising concern about Cryptosporidium parvum outbreaks in public aquatic facilities, DEL determined to test the ability of its ozone generation and injection techniques to kill this virulent microorganism. The test was designed to measure the efficacy of ozone in reducing Crypto disbursed into a tank of almost 3,000 gallons capacity (simulating a pool), under carefully measured conditions. The result was a 3 log (99.9%) reduction of the organism. More graphically, there were more than 6,600 oocysts per liter in the input of the recirculation line from the water tank and zero oocysts per liter in the recirculation output line back to the tank.
Testing Ozone for Use as a Disinfectant 
The Toxicology Group, LLC, a Division of NSF International, tested the efficacy of DEL ozone for its ability to kill E. coli. The test, repeated 3 times, used measured doses of ozone dissolved in water that was infected with E. coli, controlling for water condition and time of exposure to ozone. The result was that ozone reduced the number of E. coli organisms by 99.999% in both deionized and hard water within 30 seconds of exposure. This test meets the AOAC Official Method 960.09 (the AOAC, known variously as the Association of Official Analytical Chemists or the Association of Analytical Communities, is a 125-year-old organization that establishes uniform chemical analysis methods that are used as standards internationally).
Testing Germicidal Spray Disinfection Effectiveness of Ozone
Another test performed by NSF evaluated DEL Ozone systems for their ability to disinfect nonporous surfaces (substrates tested included: glass, stainless steel, concrete, painted concrete and plastic) using an ozone saturated spray. This test was performed using the AOAC Method 961.02 as required by the EPA’s Office of Pesticide Programs (OPP) Disinfectant Technical Scientific Section (DIS/TSS-1) (1982). The tests evaluated the efficacy of the ozone spray to eradicate various micro-organisms, including Listeria monocytogenes, Aspergillus flavus, Campylobacter jejuni, Brettanomyces bruxellensis, and Trichophyton mentagrophytes, requiring an immediate 4 log to 6 log (99.99-99.999%) reduction. The report concludes: "Based on these findings, DEL ozone systems meet the performance requirements for both broad-spectrum and hospital/medical environment efficacy claims as specified in the US EPA DIS/TSS-1."
Ozone Injection in a Warm Water Stream as a Disinfectant 
In 2006, NSF’s Engineering Test Lab evaluated the effectiveness of a DEL ozone system (identical to systems installed in public swimming venues) to determine compliance with the NSF/ANSI Standard 50 Annex H. Standard 50 specifies “evaluation criteria for materials, components, products, equipment and systems for use at recreational water facilities” including spas or hot tubs and pools, both public and residential. The research was designed to test ozone effectiveness in killing Enterococcus faecium and Pseudomonas aeruginosa bacteria distributed in a tank of water (simulating a pool or spa). The ozone was injected by standard DEL methods, and repeated measures of the water were made after various lengths of exposure. The ozone was observed to produce a 6.6 to 6.7 log reduction (greater than 99.9999%) in these organisms within 6 minutes after startup, fully meeting the Standard 50 Annex H requirements.
A Safety Analysis of Agricultural Ozone Disinfection 
Due to concerns about the safety of ozone for operators, DEL engaged NSF in 2002 to perform a “Hazard and Safety Assessment of DEL’s Ozone Surface Sanitation Systems.” These tests were performed in compliance with OSHA regulations. The result of the test was: "It is the professional opinion of the Toxicology Group, LLC that the DEL agricultural devices deliver a consistent applied ozone dose which meets both the critical level required to ensure the antimicrobial efficacy claims while still maintaining exposures below the OSHA PEL."
We’re Working On It
The development and testing of ozone sanitation equipment is continuous. As we find new applications or improved methods for ozone sanitation, we continue to perform new rounds of testing. This work is never done, but the benefits are real and on-going.