1. Field of the Invention
Ozone has been called "mother nature's elluent treatment". Ozone (O.sub.3) has been used throughout Europe to disinfect and improve the quality of drinking water since 1906. When the first commercial plant for an application of this sort began operating at Nice, France. Several thousand installations are now in operation, the most of which are in Europe. Ozone is used principally in water treatment for taste and odor enhancement. Present day demands for cleaner effluent streams from Industrial Plants, along with simpler, more efficient means of treating municipal sewage indicate the much greater use of ozone, if its cost of production can be kept competitive with chlorine, chlorine dioxide, peroxide, and permanganate.
The more recent findings that chlorinated water may produce carcinogens with trace hydrocarbons is a further reason to expand the use of ozone as a disinfectant and sterilant.
2. Description of Prior Art
The basic elements of an ozonation system are an ozone generator and a mixing tank or column.
The heart of the generator is the ozone producer consisting of a pair of large-area electrodes, either flat or concentric tubular, separated by an air gap and a presence of a high-voltage, high frequency silent electric discharge, or corona, ozone is generated from oxygen in the gap between the electrodes. Most generating units are designed to operate in the 5000 to 25,000 volt range, and at frequencies up to 1000, or more H.sub.z.
Many of the operating problems encountered in this type equipment is the heat in the generating area, along with accumulations of nitric acid and nitrogen oxides which occur as by-products of ozone generation from air having a dew point above -40.degree. C. Use of air not only requires drying prior to introduction to the generator, but decreases the oxygen conversion to ozone to 50% of that produced when pure oxygen is used.
Several improvements have been developed in the generation of ozone. Acid-resistant materials have reduced the need for dry air; and electronic circuitry has been fruitful in the design and use of "tuned" circuits that is - spaced or shaped surges of power set resonant circuits "ringing" with a series of descending electronic echoes that maintain the corona at an ozone generating energy level between pulses. This form of electronic coasting has significantly reduced power consumption. Power consumption of 20 watts per gram of ozone has been reduced to 10.+-..