Bacteria are common in the environment and that includes well water, but generally they are not harmful. However some are and their presence in drinking water are classified into two groups, one verifying that the water is certainly contaminated with animal or human waste and the other indicating that this may also be the case, but it is not certain. The certain evidence of contamination is indicated by the presence of E. coli, which is also referred to as Faecal Coliform, the less important evidence is indicated by the presence of coliform bacteria in general and these are referred to as Total Coliforms.
E. coli or Faecal Coliform
The presence of this type of bacteria in the water confirms that the water is indeed contaminated with animal or human waste. Some microorganisms in this waste may cause only short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. Some severe strains are much more dangerous and may occasionally cause acute diarrhea that can lead on to kidney failure and death. Because E.coli are only present in animal and human waste and in very high numbers, they are definite proof that faecal contamination (animal or human waste) is present in the water.
Coliforms are a group of closely related bacteria, of which most are harmless; however, the presence of coliform bacteria in drinking water suggests that there may well be disease-causing microorganisms in the water. These coliforms are a broad class of bacteria which are found in the natural environment, but they also live in the digestive tracts of humans and many animals. The presence of coliform bacteria in tap water suggests that there may be a problem, because these bacteria are frequently found in locations similar to the kind of environment preferred by the type of bacteria that cause disease.
Although many types of coliform bacteria are harmless, their presence indicates that the water may be contaminated by animal or human waste and although E. coli may not be present in the water, the presence of Total Coliforms may well cause some health problems, which include diarrhea, cramps, nausea and vomiting, but at levels that are less serious for healthy people, but they can lead to more serious problems for people with a weakened immune systems, such as the very young and elderly.
To protect against bacteria Ultraviolet Sterilisers are used.
The Solution To Bacteria In Water
Ultraviolet water purification lamps produce UV-C or “germicidal UV,” radiation of much greater intensity than sunlight. Almost all of a UV lamp’s output is concentrated in the 254 nanometers (nm) region in order to take full advantage of the germicidal properties of this wavelength. Most ultraviolet purification systems are combined with various forms of filtration, as UV light is only capable of killing microorganisms such as bacteria, viruses, moulds, algae, yeast and oocysts like cryptosporidium and giardia. UV light generally has no impact on chlorine, VOCs, heavy metals and other chemical contaminants. Nevertheless, it is probably the most cost effective and efficient technology available to homeowners to eliminate a wide range of biological contaminants from their water supply. The UV bulb has to be replaced every 12 months to ensure ongoing efficiency and can be supplied and or fitted by us as required.
UV water treatment offers many advantages over other forms of water treatment for micobiological contaminants. Most importantly, it does not introduce any chemicals to the water, it produces no bi-products and it does not alter the taste, pH, or other properties of the water. Accordingly, in addition to producing safe drinking water, it is not harmful to your plumbing and septic system. Further, it is easy and cost-effective to install and maintain without any special training.
How it Works
Ultraviolet purification uses a UV light source (lamp) which is enclosed in a protective transparent sleeve (usually quartz). The lamp is mounted such that water passing through a flow chamber is exposed to the UV-C light rays. When harmful microbes are exposed to the UV rays, their nucleic acid absorbs the UV energy, which then scrambles the DNA structure of the organism. The cell is rendered sterile and can no longer reproduce. The cell is now considered dead and is no longer a threat.
What Contaminants Does Ultraviolet Remove?
There are no micro-organisms known to be resistant to UV, unlike chlorination. UV is known to be highly effective against bacteria, viruses, algae, moulds and yeasts and disease causing oocysts like cryptosporidium and giardia. In practice, bacteria and viruses are the cause of most major waterborne pathogenic diseases. Of these enteric viruses, hepatitis virus and Legionella pneumophila have been shown to survive for considerable periods in the presence of chlorine, but are readily eliminated by UV treatment. For most microorganisms, the removal efficiency of UV for microbiological contaminants such as bacteria and virus generally exceeds 99.99%. Specifically, the following are moved to an efficiency of greater than 99.99%: E-coli, Salmonella typhl (Typhoid fever), Salmonella enteritidis (Gastroenteritis), Vibrio cholerae (Cholera), Mycobacetrium Tuberculosis (Tuberculosis), Legionella pneumophila (Legionnaires’ Disease), Influenza Virus, Polio virus and Hepatitus A Virus (better than 90%). Countertop UV systems are generally not recommended for removing oocysts such as giardia and cryptosporidium unless equipped with a 0.5 micron carbon block pre-filter since the exposure time the contaminant has to the UV ray is not always long enough to provide an adequate UV dose for disinfection of these more complex organisms. Whole house UV systems like our Aqualightech UV on the other hand, are capable of killing waterborne oocysts at household flow rates when a properly sized model is selected for the application.