Some scientific info

Ozone (O3) is a molecule, consisting of three oxygen atoms. It is an allotrope oxygen that is much less stable than the diatomic O2. The ozone layer in the upper atmosphere filters potentially damaging ultraviolet light from reaching the Earth’s surface. It is present in low concentrations throughout the Earth’s atmosphere. It has many industrial and consumer applications.

Ozone can be used to remove manganese from water, forming a precipitate which can be filtered:

2 Mn2+ + 2 O3 + 4 H2O → 2 MnO (OH) 2 (s) + 2 O2 + 4 H+

Ozone will also turn cyanides to the one thousand times less toxic cyanates:

CN- + O3 → CNO- + O2

Industrial Use

Mainly the ozone is used in the preparation of pharmaceuticals, synthetic lubricants and other organic compounds. It is also be used to bleach substances and for killing microorganisms in air and water sources. Many drinking water systems kill bacteria with ozone instead of the more common chlorine as it does not form organ chlorine compounds, nor does it remain in the water after treatment. The Safe Drinking Water Act mandate that these systems introduce an amount of chlorine to maintain a minimum of 0.2 ppm residual Free Chlorine in the pipes, based on results of regular testing. Ozone is also a cost-effective method of treating water, where there is electric power since it is produced on demand and does not require transportation and storage of hazardous chemicals. Once it has decayed, it leaves no taste or odor in drinking water. Other important applications of ozone:

  • Disinfect water in place of chlorine
  • Kill bacteria on food or on contact surfaces;
  • Sanitize swimming pools and spas
  • Kill insects in stored grain
  • Scrub yeast and mold spores from the air in food processing plants;
  • Wash fresh fruits and vegetables to kill yeast, mold and bacteria;
  • Chemically attack contaminants in water (iron, arsenic, hydrogen sulfide, nitrites and complex organics stick together as “color”);
  • Eradicate water borne parasites such as Giardia lamblia and Cryptosporidium in surface water treatment plants.

Swimming Pools

Ozone has been in regular use for more than fifty years in the west European countries, such as France, Germany and others as they realize the consequences of chlorine gas.

Ozone has also been in use in Europe since the 1890’s for drinking water purification. Some large cities in the United States such as Los Angeles and Milwaukee now boast the best drinking water in America since they began using Ozone as a purification method.

Ozone, although a disinfectant or sanitizer and oxidizer, it is normally referred to as the primary oxidizer and alternative sanitizer when referring to its use in swimming pools in the United States.

Here are some useful details that have to be mentioned when speaking of ozone:

  • Ozone destroys viruses and bacteria such as e-coli and legionaries, and others.
  • Ozone is over one thousand times faster acting than chlorine at oxidizing and destroying bather load in a swimming pool. This drastically reduces chlorine requirements.
  • Decreased chemical usage – significant savings considering the cost of chlorine
  • Better water clarity
  • Reduction or total elimination of chloramines
  • Reduction or total elimination of odors-particularly valuable in indoor pool environments
  • Smoother water feel
  • No red itching eyes normally caused by chloramines
  • Very effective at destroying viruses and organisms
  • pH neutral

Ozone gas is introduced into water by means of either a venturi injector creating a vacuum to suck ozone gas into the water or with direct injection or diffusers by pushing the air into the water with an air pump. The Ozone gas mixes with the water. The best saturation of Ozone in water is obtained when many fine bubbles of Ozone is introduced which provide more total surface area of Ozone contact.

There are basically two ways that Ozone is produced by man or by nature. One is known as Corona Discharge (CD) and the other is passing air across special Vacuum Ultra Violet lamps. (VUV) often times referred to as UV Ozone or Very Ultra Violet Ozone.

Manufacturers of each of these technologies say the other technology uses more electricity. In reality they are pretty equal. In some applications VUV lamps use less and others Corona uses less, but in any event, not by much and not an issue. Neither uses much electricity.

Another statement by manufacturers is ease of maintenance between the two technologies. This is also subjective and used by who is selling what. Corona manufacturers require replacing check valves and hoses annually, and to wear protective gloves when doing so. Corona cell components also need periodic maintenance. VUV Lamp Ozone manufacturers state their lamps run between 9,000 and 20,000 hours, so they may need replacing depending upon pool filtration run time every several to seven or so years.

Both Vacuum Ultra Violet lamp Ozone systems and Corona Discharge systems are available for use in commercial swimming pools ranging to the millions of gallons.

Extremely large Corona Discharge systems are used for large metropolitan municipal water treatment systems.

Although this discussion is dealing with swimming pools, there are many applications for both Ozone technologies such as, but not limited to, water cooling towers, laundry systems, drinking water, wells and cisterns, wastewater treatment, aquariums, fruits and vegetables, meats, odors, medical, ice machines, many more.

Corona Discharge (CD) Ozone Generators

Corona discharge is a high electrical energy field such as lightning in natural occurrences, and by man using two highly energized metal or ceramic plates or chambers with a narrow gap in which air flows through. The arcing of this high electrical energy called the corona field alters the electron structure of all elements in the air passing through the chamber.

When man made corona discharge ozone generator systems are fed pure oxygen input and also very dry air passed through an air drier, they produce high quantities of Ozone. When manufacturers of Corona Discharge Ozone systems provide Ozone output production graphs, they sometimes use pure oxygen and very low humidity or dry air in testing. At a minimum, they often use drier air than normally found in many areas of the United States.

In reality, Oxygen concentrators and air dryers are price prohibitive for the backyard pool so ambient air only is passed through the cell. Pure Oxygen does not exist in ambient air, and in some areas of the country, humidity is very high. Commercial CD systems that can afford the cost, and do provide Oxygen concentrators require additional maintenance such as cleaning concentrator filters, and life cycle issues. They also require Ozone monitoring safety devices.

(Ambient air: A colorless, odorless, tasteless, gaseous mixture, mainly nitrogen (approximately 78 percent) and oxygen (approximately 21 percent) with lesser amounts of argon, carbon dioxide, hydrogen, neon, helium, and other gases.

b. This mixture with varying amounts of moisture and particulate matter, enveloping the earth; the atmosphere.)

Corona Discharge systems provided with ambient air input to the chamber such as backyard pools have certain issues that arise. Below are two primary issues.

One issue is the high Nitrogen content of ambient air. As mentioned previously, all elements passing through a Corona chamber are altered. Nitrogen is the primary substance in air, and altering its state creates harmful byproducts such as nitric acid (nitric acid: A clear, colorless to yellow liquid that is very corrosive and can dissolve most metals. It is used to make fertilizers, explosives, dyes, and rocket fuels) and Nitric oxide (nitric oxide n. A colorless, poisonous gas), along with other Nitrous byproducts. To top it off, Nitrates. Nitrates are Algae food.

Another issue is Humidity. Ever wonder why it is that when you reach for something or someone in the winter time where the air is dry and you are zapped by a bolt of static electricity? Ever wonder why in the summer time, or when outdoors this does not occur? These answers are simple—Ambient Air Humidity. If humidity affects electrical conductivity in ambient air, could it not directly relate to the electrical field in a Corona Discharge cell hindering output?

In review: Corona Discharge systems that are supplied pure Oxygen and dry air produce high levels of pure Ozone. Corona Discharge units that are provided only ambient air, such as backyard pool applications, create Nitrogen byproducts and may experience diminished outputs with increased humidity.

Vacuum Ultra Violet (VUV) Ozone Generators

VUV lamp Ozone generators simulate nature’s way of creating the Earth’s outer Ozone layer. This is accomplished by creating the equivalent of the Sun’s solar light energy spectrum in the 185 nanometer range.

The outer Ozone layer is a continual process of the spectrum interacting with Oxygen and is considered very beneficial to our existence.

There are differences in Ozone generation using VUV lamps versus Corona Discharge (CD) equipment.

Ozone lamps are not affected by humidity. In fact, humidity is said to increase the effective oxidizing potential of Ozone generating lamps by drawing properties of the germicidal spectrum through the filtering quartz. Some refer to this as Advanced Oxidation Technology (AOT) and others Advanced Oxidation Process (AOP). Ozone lamp systems perform very well in humid places, where there are issues with ambient air CD systems.

As with CD technology, the greater and purer the Oxygen amount introduced to the input chamber of the lamps, the higher output of Ozone.

Unlike CD systems that create potentially harmful Nitrogen byproducts with ambient air, Ozone lamps only alter Oxygen converting it to Ozone. Ozone lamps are not known to create harmful byproducts.

Ozone lamp systems normally do not require the maintenance of CD systems. The nitrogen byproducts created by CD hinder the effectiveness of check valves, injectors, and hoses which is not as evident with lamp Ozone generators. No special clothing or gloves are required for maintenance of lamp Ozone systems. Note: Do not look directly at an Ozone lamp. Ozone lamps also contain mercury, so proper disposal must be considered.

In review: VUV Lamp Ozone generating systems perform very well in all environments. They normally require less maintenance than CD systems. Warranties are often longer in duration. Ozone lamp systems are normally less expensive to purchase.

Check our shop to see available swimming pool ozone generators.