Electrochemical Ozone Generation

An interesting review article on electrochemical ozone generation will appear in the journal of Ozone Science and Engineering:

The Electrochemical Generation of Ozone: A Review, Paul Andrew Christensen a , Taner Yonar b & Khalid Zakaria c
a School of Chemical Engineering and Advanced Materials, Bedson Building, Newcastle
University, Newcastle upon Tyne, NE1 7RU, United Kingdom
b Engineering and Architecture Faculty, Uludağ Universitesi, 16059, Bursa, Turkey
c School of Civil Engineering and Geosciences, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
Accepted author version posted online: 15 Feb 2013.Published online: 23 Apr 2013.

A brief summary of the article is shown below. A discussion of all methods of ozone generation can be found at the Sparta website.

Most commonly, ozone is produced in the gas phase using the corna discharge method, but it can also be generated in solution at an anode elecrochemically. The electrochemical generation of ozone has advantages including: low voltage operation, the possibility of generating high concentrations of ozone in the gas and liquid phases with high current efficiency, no need for
gas feeds and simple system design.

Essentially, if you directly produce the ozone in water you eliminate the need for feed gas preparation and dissolution steps for ozone water treatment applications. While the process has been shown to work well, it has not scaled up as economically as corona discharge systems and thus large scale ozone generation is done in the gas phase. Nonetheless, commercial electrochemical systems are used in smaller scale systems such as ultrapure water and other applicatios.

Electrochemical ozone generators have employed a variety of materials and designs. Anodes materials typically used are Pt, PbO2 and Boron doped Diamond. Both separated and no separated cells have been employed including so call solid polymer elecrolyte cells using Nafion membrane technology.

While a generally accepted mechanism for electrochemical ozone generation has been proposed, different anode materials result in drastically different results with small quantities of impurities greatly affecting performance.

The early studies of electrochemical ozone generation were carried out at low temperatures in corrosive and, in some
cases, expensive electrolytes and primarily using Pt anodes. Later, the favored anode material was PbO2 in more conventional, acidic electrolytes, at temperatures around 0 ◦C. These materials require high current densities for high
current efficiencies, typically ca. 1 A cm−2. It is clear that high ozone current efficiencies can obtained at certain anodes like diamond, but at high energy cost. Ni/Sb-SnO2 anodes show high activity at low current densities which means low production per unit area. some of these new catalysts might be directly deposited on nafion lowering overall cell costs.

While the polymer electrolyte systems offer attractive potential they may preclude use of real world water since Nafion is very sensitive to hardness that can significantly shorten the membrane life time. Another issue with electrochemical ozone systems is either the cost, lifetime or toxicity of the materials used. Despite these issues niche applications are already being developed and the long term potential of electrochemical ozone generation appears bright.

Share

2013 World Congress of the International Ozone Association (IOA) and International UV Association (IUVA) to Run 9/23-26 in Las Vegas

The IOA/IUVA World Congress will take place in las Vegas, NV from September 23rd to September 26th. The world congress of these two organizations is held every two years and roates between the US/Canada, Europe and Japan.

The congress will feature comprehensive techemical sessions covering various aspects of ozone, UV and advanced oxidation processes, a commercial exhibition many ozone and UV system suppliers as well as a social program of receptions and dinners to allow for networking.

The technical program will cover primarily ozone water treatment, UV water treatment and advanced oxidation applications. Authors from around the world will present papers, many of which will ultimately appears in refereed scientific journals. Time is allowed during and after the technical sessions to ask questions of the speakers to get a more in depth understanding of the tiopics.

To register visit worldcongress2013.org.

Share

Clearwater Florida Installing RO/Ozone Water Treatment System

Clearwater Florida is installing a system to convert 6.5 MGD of brackish water into drinking water. The process involves using RO to remove the dissolved solids. The RO water is then treated with ozone. Poole & Kent Co of Florida has been awarded a contract for the installation of the equipment.

Ozone water treatment is used extensively in Florida and the US for drinking water treatment to remove various contaminates and to disinfect drinking water to make it safe for human consumption. Ozone is produced using ozone generators from air or oxygen. Onnce it disinfects the water, the ozone reverts back to oxygen leaving no residual chemicals. It is also one of the strongest disinfectants used by municipal drinking water facilities killing all the major desease causing organisms.

Share

Milwaukee Now a Leader In Water Testing and Treatment

20 years ago Cryptosporidium passed through a Milwaukee water treatment plant. The microorganism caused an estimated 400,000 cases of gastrointestinal illness and at least 69 deaths. It was the largest waterborne desease outbreak recorded in U.S. history.

Since the outbreak, the city’s water utility, which draws its supply from Lake Michigan, has invested $417 million in improvements to infrastructure, monitoring and treatment.

Beginning in 2004, Milwaukee Water Works launched an aggressive program to monitor for emerging contaminants including estrogen and testosterone, flame retardants, pesticides, explosives and pharmaceuticals. Milwaukee Water Works tests for more than 500 chemicals annually, and posts its monitoring results online. The majority of water systems in the US focus only on a standard list of 91 contaminants regulated by the U.S. Environmental Protection Agency.

Since the Cryptosporidium outbreak of 1993, Milwaukee has made numerous improvements to its drinking water treatment. An $11 million project extended the Howard Avenue water intake 4,200 feet to a distance of two miles off Lake Michigan’s shoreline, beyond the path of contamination from the city’s industrial harbor. The water enters a nine-step treatment process that includes ozone disinfection, sedimentation and filtration.

At the other end of the city’s water system, the Milwaukee Metropolitan Sewerage District tested a state-of-the-art sewage filtration system. The goal was to catch emerging contaminants resistant to removal by conventional wastewater treatment along with phosphorus, a nutrient that contributes to algae blooms and fish kills.

As a result of the improvements, Milwaukee has become a leading municipality with respect to drinking water treatment.

Share

San Diego Moves Forward with IPR Demonstration Employing Advanced Oxidation

San Diego City Council members approved a Water Purification Demonstration project using a indirect potable reuse (IPR) program.

Implementation of an IPR would provide a significant new local water supply, while reducing the amount of primary effluent discharged to the ocean, helping the City avoid a $1.5 billion upgrade of the Point Loma Wastewater Treatment Plant.

IPR projects take tertiary treated municipal wastewater through an extensive filtration process using membranes followed by some form of advanced oxidation. Advanced oxidation methods used include ozone/peroxide and UV/peroxide. These methods can remove micro pollutants and kill any remaining micro organisms. The water is then normally injected into a well field for later recovery for drinking water use. A direct potable reuse project (DPR) would take the water directly to a drinking water treatment plant.

A two-year study of a 1 MGD (3,785 m3/d) demonstration project at the North City Water Reclamation Facility (WRF) demonstrated the robustness of the multi-barrier MF/RO and advanced oxidation arrangement to produce better-than-potable-quality water from tertiary effluent. The California Department of Public Health (CDPH) gave conditional approval to the proposed IPR concept.

Share