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The Pseudomonas Aeruginosa Bacterium In the last issue of SPN, Robbie Phillips, STA’s Lead Pool Plant Expert, shared his knowledge on Pseudomonas aeruginosa, a growing problem for pool operators. Here, in the second part of the feature, he discusses prevention methods for this harmful and prolific bacterium


n recent years, pool operators across the UK have been experiencing Pseudomonas aeruginosa (P. aeruginosa) outbreaks at their facilities, in record numbers. Prevention is important, as it is an opportunistic pathogenic bacterium that is responsible for both acute and chronic infections. To prevent the uncontrolled growth of (P. aeruginosa), the following practices are recommended for pool plant operators: 1. Collect water samples from the pools and spas etc., monthly and have these analysed by an accredited laboratory (test for the recommended suite of bacteria). On an annual basis, take water samples and swabs from inside the filters, balance tanks, overflow channels, skimmers etc, for bacteriological water analysis. Act on the results if necessary. 2. Simple tests for Pseudomonas are available and can be done by the knowledgeable pool manager to supplement lab tests. 3. Pressure test the pool recirculation systems to make sure there are no suction side breaks in the lines which may be allowing dirt to enter the closed systems. 4. Institute rigorous poolside and shower area maintenance procedures. The purpose of cleaning decks is two–fold. Oil, grease, dirt, bacteria and organic debris must be removed through sweeping, rinsing, power washing, and scrubbing with an all purpose cleaner, detergent, or degreaser which is compatible with chlorinated pool water. But more importantly, decks






must be disinfected to prevent bacterial growth, including P. aeruginosa, and the formation of a slippery biofilm layer. The best, and least expensive way to disinfect a pool deck, is to spray a 20 to 1 solution of water and sodium hypochlorite on the deck, and rinse with a high-pressure nozzle and hose. For clean–up of blood or bodily fluids, and to preventing transmission of blood borne pathogens, the surfaces, or any contaminated surface, should be cleaned with 5.25% sodium hypochlorite diluted to between 1:10 and 1:100 with water. This is equivalent to disinfecting with a 1:20 solution of 10–12% sodium hypochlorite (liquid pool chlorine). Clean and disinfect the decks on a nightly or at least twice weekly basis, depending on the level of facility use, and, immediately after any contamination with blood or bodily fluids. Attempt to keep patrons in street shoes off the poolside and where possible poolside/changing wet areas. Ensure both filters and balance tanks are inspected, particularly for biofilm contamination (yearly for pools and bi-annually for spas). Ensure appropriate treatment if required. Spa balance tanks should be subject to periodic rigorous physical and chemical cleansing (see STA PPO Manual). Require that infants and young children who are not yet toilet trained wear tight fitting rubber (neoprene) pants over swim diapers (double nappy system as recommended by STA) while in the pool. Aerosols on an inflatable are a possible source of infection

Institute rigorous poolside and shower area maintenance procedures to avoid problems such as contaminated gratings

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Also, ensure that adequate nappy change provisions are present and maintained at a high level of hygiene. 10. Shock spas daily and pools at least weekly where required, and/or per risk assessment or as needed if combined available chlorine levels exceed recommended levels. 11. Any shock dosing requires robust risk assessments and controls by competent persons. These assessments and controls apply to all staff and contractors involved. 12. Do not remove high levels of chlorine from the water with sodium thiosulphate, dilution is the best way from a freshwater source. Wherever possible let chlorine levels return to normal gradually after the breakpoint has been achieved. 13. Dilute the water regularly to control for TDS build up. This dilution will also control combined chlorine levels. If repeated high levels of Pseudomonas are found in the pool or other facilities, the following procedures should be followed: 1. Rinse pool circulation pipes, balance tanks and all circulation ancillary equipment with high levels of free chlorine, then where practical drain the spa, small pool etc. completely. It may be necessary to clean all practical sections physically. 2. If necessary, remove the sand or other filter media from the filter tanks, and either dispose of the media safely and hygienically or chemically cleanse the media. 3. Read the material safety data sheets (MSDS) before beginning work. And finally, all treatment and inspections should be carried out using robust risk assessments and controls, and be to recommended UK standards. For further information on the points discussed in both Pseudomonas aeruginosa articles, and for further advice on pool and spa plant training, call the STA, email them at or visit their website. STA 01922 645097 28/05/2017 17:58

SPN (Swimming Pool News) June 2017  

Informing the pool and spa industry since 1959. Covering the UK's wet leisure market, SPN (Swimming Pool News) is the UK's longest running a...

SPN (Swimming Pool News) June 2017  

Informing the pool and spa industry since 1959. Covering the UK's wet leisure market, SPN (Swimming Pool News) is the UK's longest running a...