There are a number of stringent measures in place for pool operators. The have a range that pool water is to be kept between to ensure effective disinfection, the pool operators will take regular water samples throughout the day measuring the amount of free and total chlorine. There will be a regular cleansing programme in palce for maintenance of pool water, this will based on a number of different factors. There are also regular water samples taken by independant specialists for micrbiological analysis.
There are a variety of different ways to achieve effective disinfection in pools; chlorine, chlorine and ozone; bromine; uv - massive advances are being made with new technologies all the time. I have worked in a variety in my time, all had their different good points.
There will be a number of set procedures in place to pool water in tip top condition, and to deal with variety of things that swimmers do in the water (probably not for open discussion on a family friendly forum, ask by pm). Theses will be standardised for us here is the UK, when researching this on the web, a lot of the guidance that you find will be US based, the run to different protocols over there.
You will generally find that levels of disinfection in pools in the uk much higher than in europe. People are normally covered with a range of non-pathogenic and pathogenic organisms, particularly in the mouth and intestines, and when bathing these can contaminate the water. Going to the toilet and showering before swimming can reduce both the microbiological and organic (sweat and urine) contamination of the water and should be encouraged. Customers should be advised not to swim if they are suffering from an infection that may be passed on through the water, particularly if they have diarrhoea. Ideally they should not swim within a fortnight of diarrhoeal disease. In order to reduce transmission of the organisms shed by infected individuals, a residual disinfectant concentration is maintained which should kill most of these organisms and prevent cross transmission through water that has not passed through the treatment plant since it was contaminated.
A number of infections can be passed whenever a group of people are in close contact. Respiratory infections in particular are probably transmitted as readily in swimming pool environments as in other social situations but adequate disinfection should ensure that transmission through pool water is not common. If disinfection is inadequate, or if hygiene standards are not maintained, infection via pool water may happen.
Hepatitis B virus and the human immunodeficiency virus (HIV) are carried in blood and other body fluids. Infections are transmitted by inoculation into body tissue - by sexual intercourse, injection, cuts, etc. The viruses are susceptible to the action of disinfectant and neither of these viruses can be transmitted as the result of using a swimming pool or spa pool. Sexual activity within pools probably carries the same infection risks as sexual activity anywhere else, and is not related to pool treatment.
Staphylococcus aureus can cause boils, abscesses and infected wounds. Where S aureus is resistant to methicillin and other antibiotics it is termed MRSA. There is no evidence that S aureus or MRSA can be transmitted through normal swimming pool use. There is no evidence to justify the exclusion of MRSA carriers from swimming pools or hydrotherapy pools but people with wounds contaminated with MRSA should be excluded from using pools, particularly hydrotherapy pools
There is an excellece source of information for any pool operator: http://www.pwtag.org/home.html
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