Air Ionization: Don’t Confuse It With Photoionization or Ozonation
During another of my recent presentations of the Aerisa air purification technology, a client asked, “Your odor control systems appear much safer than photoionization or ozonation–Would you please explain the differences?”
As stated in my recent email, confusion about this has been unfortunately created by inaccurate, misleading, or non-information given by others. Air ionization is a different technology than ozonation or photoionization (or more accurately, photocatalytic oxidation).
Air ionization systems supply highly-ionized air (i.e., with O2+, O2– ions) into the space to proactively attack the contaminants at their source while vastly improving in-area working conditions. As a second purification step, outside air may be ionized and mixed with pre-treated facility air to deliver high quality exhaust.
The ions created by air ionization are completely natural and safe– you’re breathing them at some concentration right now! The Aerisa technology increases these oxidative ions in the application area (e.g., headworks building, dewatering room, tank headspace, large pump station) to safely provide odor and corrosion control.
Photocatalytic Oxidation (PCO) is a new odor control technology that utilizes numerous UV bulbs, a metal (titanium or potassium) compound supported on media (such as granular carbon) and humidity to treat exhaust from a space. This technology produces hydroxyl radicals and
unstable peroxides, very oxidative compounds, but extremely harmful to humans and which must be used in an exhaust-only configuration. In my opinion, PCO is meant for low flow rate, highly contaminated gas streams, as 20+ UV bulbs are needed per 1000 cfm. Thus, scalability for large flow rates is questionable as bulb maintenance, media replacement and
power costs will be unactractive. PCO also generates sulfuric acid that must be drained to waste.
Ozonation was discussed in my recent email. Though the equipment itself may appear similar, ozone (O3) generators commonly operate at 30,000-40,000 volts, whereas Aerisa’s ionizers operate at less than 3,000 volts to negate ozone production. As stated previously, the OSHA standard for ozone is 0.10 ppm average over an 8-hour work shift-so, it doesn’t take much to be a personnel safety issue. Therefore, gas phase O3 applications are typically for high concentration odors and for unattended, small spaces such as pump stations. Ozone attacks natural rubber, nitrile, nylon, and mild steel–this too must be considered.