The Natural Alternative
As published in the AHGA - Australian Hydroponic & Greenhouse Association
Soilless Australia Magazine Vol 2 2009.
AHGA is now known as PCA - Protected Cropping Australia.
Ozone or O3 is one of the most effective bactericides known to science, but for many people it is still a mystery. Put simply ozone is a gaseous form of concentrated oxygen O2. It can be naturally observed as the fresh smell during a thunderstorm.
The use of ozone in hydroponic agricultural applications is expanding as farmers seek to increase crop yields, reduce operating costs and reduce environmental degradation by minimising the use of water and chemicals on the farm. Significant water savings can be achieved be reusing the feed water in a closed system but the potential for disease outbreaks is greatly increased, so this risk needs to be carefully managed.
Ozone is pH neutral and is one of the most powerful, fast acting oxidizing agents available for the sterilization of water. On the oxidation chart it lists above chlorine, iodine and bromine. However, unlike these chemical options, ozone dissolved in water will simply break down into oxygen within about 20 minutes, leaving no chemical residues.
This also makes ozonated water the ideal sanitizing agent for washing produce to remove bacteria, fungi and moulds. This process greatly extends the shelf life of the produce without the use of any chemicals such as chlorine. Ozone use in food production has been granted GRAS status (Generally Recognised As Safe) by the US FDA (Food & Drug Administration).
As ozone is generated on site there are no storage costs, nor the ongoing costs of purchasing chemicals. The safety risks involved with chlorination systems and the storage of dangerous chemicals such as hydrogen peroxide are also eliminated.
There are two types of ozone generators, UV (Ultra Violet) lamp units and CD (Corona Discharge) units. Black Max Ozone GeneratorsTM only use the UV method of ozone production because it is extremely reliable, requires virtually no maintenance, needs no air dryer, has a constant output even in high humidity locations and will not produce nitric acid as a potential unwanted by-product.
The Black Max Ozone SystemTM injects ozone directly into the holding tank and/or nutrient solution. The ozone destroys organochlorines, controls algae and breaks down many herbicides and pesticides. Ozone also destroys the fungi, pathogenic bacteria and viruses which thrive in oxygen depleted water. These disease causing microbes can greatly reduce plant growth and yields, or even destroy a whole crop.
The level of dissolved ozone will naturally adjust as the injected ozone does its job and excess ozone simply gases off through the water. The water will become super oxygenated as the ozone breaks down into oxygen. The beneficial aerobic bacteria will thrive in the oxygen rich environment.
Normally oxygen levels can be very low in the nutrient solution and become even more depleted as the temperature rises. This is the ideal breading ground for bacteria and viruses. Feeding the plants with disease free ozonated water, containing abundant oxygen, promotes rapid healthy root development, faster plant growth, healthier plants and higher yields.
There are two ways to introduce the ozone into the water. One is to use the vacuum created by an ozone jet or venturi. This jet can be attached to a submersible pump and placed into the tank water. Alternately the jet can be attached to a pipe placed into the tank with the water feed to operate it coming from an external pump.
The other way is to use an injector or injector manifold where the ozone is also introduced under a vacuum created by the injector, but the injector is located in the external pipe work. In this case the ozone can interact with the water in the plumbing as well as in the tank. Which system you use is dependant on the pump size, available water flow rates and the type of installation.
Hydroponic farmers typically report no more problems with waterborne diseases and are very happy with their crop after installing one of our Ozone Systems.
In summary, to make the most of your available water, oxygenate your water, reduce the risk of disease outbreaks, minimising the use of chemicals and save money along the way, you would have to say that ozone is the natural alternative
By Gary Davies