Sterilisation the Chemical-Free Way

A safe, environmentally-friendly solution to water disinfection

The problems associated with water storage

Over the past few years water has become a scarce and valuable resource as populations and consumption rise and our climate continues to evolve. As such, many people have either put in rain water harvesting systems or have invested in boreholes and store their own water on their properties.

However a humid water tank provides the perfect breeding ground for bacteria and pathogens, which can either already be present in the water or pocket of air above the water level. When direct sun shines on the tank, the water evaporates and condenses where it comes into contact with any air-borne bacteria found in the headspace. It then falls back into the tank as contaminated water. These conditions proliferate during the warm summer months and even more so if the water in the tank is not circulated.

Stagnant can pose a major health risk as it provides a better incubator than running water for many kinds of bacteria and parasites. Tanks that are not sealed properly allow pests such as mosquitos which can carry serious diseases such as malaria, dengue, and yellow fever, an opportunity to breed inside the tank. The foul smell associated with stagnant water is the direct result of the bacteria replicating.

Harvested rain water can contain many contaminants such as dead insects and bird droppings which contain e-coli. Dust, smoke, and soot from the air can be dissolved in rainwater before it lands on your roof. Roofing materials, gutters and piping can also introduce harmful chemicals to the water. Various water disinfection methods can be used to address the need for water treatment.

The benefits of UV sterilisation

UV-C disinfection has a long and honourable history in cleaning room air especially in the medical industry. Surface UV treatment of food has been used to extend shelf life in supermarkets, resulting in less food waste and lower stockholdings. In recent years it has grown in popularity for more applications such as high tech volume liquid treatment in breweries, distilleries, canneries and bottling facilities as well as hydroponics, fish hatcheries and domestic ponds.

UV treatment is considered safe. Since it does not add anything, it leaves no residue and therefore has as it has no effect on the taste, colour or smell of the water. There are also no health hazards associated with the use of some more harmful, corrosive chemicals used for disinfection.

UV-C light is germicidal and operates most efficiently at a wavelength of 250 – 260 nanometers. It has a photolytic effect whereby the radiation destroys or inactivates the microorganism so that it can no longer multiply and is rendered inactive.

A chemical-free water disinfection solution

Ozonetek has developed a unique Germicidal Tank Lamp (GTL) that keeps stored water hygienic by sterilising not only the water but the headspace in the tank as well.

The system was fully tested and certified overseas. Approved by the International Electrotechnical Committee (IEC), it now complies with stringent local and international standards set out for household electrical appliances and more specifically for UV radiation water treatment appliances.

Water analysis from an independant SANAS accredited testing laboratory showed a 99.8% reduction in total coliforms and 100% reduction of e-coli and faecel coliforms using the GTL. Coliforms are a broad class of bacteria found in our environment, including the faeces of man and other warm-blooded animals. The presence of coliform bacteria in drinking water may indicate a possible presence of harmful, disease-causing organisms.

The system is energy-efficient and easy to install and provided that the water is already clear or treated, will require very little maintenance. It was designed so that when the lamps reach their 12 000 hour life-span, they can easily be changed.

A single lamp can sterilise and maintain a tank of up to 5 000 litres using around 50W of power (once warmed up) operating on 220-240V.

Leave a Reply