Accidental Release of Faeces or Vomitus into a Pool
Accidental Faeces Release (AFR) can occur quite frequently and in many cases, such incidents can go undetected. AFR into a swimming pool can however lead to outbreaks of numerous infections that are directly associated with viruses, bacteria, and pathogenic protozoa. Vomitus can have a similar effect.
A pool Operator faced with any form of AFR or vomitus in the pool water must act immediately.
If the faecal release is a solid stool, it should be retrieved quickly and discarded appropriately, via the sewer. The scoop used for any such retrieval must be disinfected after use, so that any bacteria and viruses adhering to it are inactivated and will not be returned to the pool the next time the scoop is used. As long as the pool is, in all other respects, operating properly (with the required disinfectant residuals) no further action may be necessary. If, however, the response time has not been immediate (and if the contaminant is not truly solid) there is a need to take decisive and immediate action directing all bathers to leave the contaminated pool, whereby the pool can be closed to all swimmers.
In the above case, the chlorine level within the pool should be raised to at least 20ppm throughout the whole pool, for at least 3 hours. Disinfection concentrations must be measured at least three times in different locations in the pool. The pH must also be maintained between 6.8 and 7.6 at all times. Reopen the pool after the disinfection process and continue to maintain free chlorine at operational levels.
If the stool is in any way runny, (as with diarrhoea) or if there is vomitus material, the situation is potentially far more hazardous. Even though disinfection will deal (reasonably well) with the many bacterial and viral agents (that are contained with AFR and vomitus), the possibility exists that the incident is from someone infected with one of the protozoal parasites, such as Cryptosporidium or Giardia.
For the above reasons, the following procedures should be adopted:-
Direct all bathers to leave the pool immediately.
Shut off the plant to reduce the spread of any contaminants.
Physically remove as much of the offending solid matter as is possible.
Vacuum clean any such offending sedimentation direct to waste, using a mobile vacuum (disinfect the vacuum cleaner plant immediately after its use)
Thoroughly clean and disinfect any affected deck surface with 100ppm chlorine
Turn on the PWT plant and ensure that it is operating at its maximum efficiency.
Raise and maintain the free available chlorine in the pool to 20ppm for 8- hours (as in hyper-chlorination). A mixed solution of Calcium
Hypochlorite may be the most convenient chemical to achieve this result quickly.
Ensure that the chlorine concentration is found consistently throughout the whole pool by testing a minimum of three widely spaced locations.
DPD test kit for normal use cannot be easily used for this purpose. Better results will be obtained by using “chlorine test strip” with a far broader test range. Alternatively, careful ‘dilution’ testing can be employed.
Disconnect, or disable, the automatic chemical controller and all heating equipment and run the plant continuously throughout the 8 hour long disinfection process.
Backwash the filter plant at the end of the disinfection process. Extend the backwash process for as long as possible. Use the manual bypass valve on the water make-up system to support an extended backwash process. Monitor the rising water levels with the Backwash Detention Tank appropriately.
Re-open the pool at the end of the disinfection process, when free available chlorine is reduced to acceptable operational limits. Chlorine levels can be reduced using sodium thiosulphate.
The willingness of Lifeguards and Pool/Plant Operators to act is both critical and problematic. It is unlikely that Pool Operators will know (with any certainty) what, or who, caused the diarrhoea incident. Similarly, a significant number of incidents could happen without staff being aware of them. The most important contribution that a Pool Operator can make to the problem is to guard against it with good public education and vigilance, whereby all Lifeguards and other staff are fully aware of the public health risks.
When hyper-chlorination is warranted, don’t forget to turn-off the pool system.
Important Note: The above information is provided as guide. Future best practice may require change to these requirements. Any guidance or instruction that is available from the relevant State or Territory Departments of Health (either now or in the future) should take clear precedence over the above information.