An overview of recent relevant research and knowledge By Alan Lewis
Pool and Spa owners and maintenance people are concerned about the need to keep the pool water safe and healthy at all times. Most know that the aim of disinfection is to kill pathogens in 50 seconds (WHO standards). This is all the time it takes to transmit diseases between bathers in a pool or spa. Such a requirement can often be found laid down in official regulations and guidelines.
There is however a general lack of awareness that pathogenic cells can be found present in most pool environments in two forms: “ Planktonic ” – floating in the water – and/or “ Sessile ” – attached to a wet surfaces.
A LURKING HEALTH HAZARD
A biofilm is a symbiotic community of microorganisms attached to a solid wet surface. It can include bacteria, fungi, yeasts, protozoa and other microorganisms, some of which are likely to be pathogens. They happily colonise many household surfaces such as toilets, sinks, cutting boards, and more insidiously the linings of our water pipes – both supply and disposal. This is also why we are encouraged to clean our teeth everyday. Usually, the spa or pool owner / operator is not cognisant of their presence. No amount of shock treatments of disinfectants or UV, can remedy the situation. Not many pool services, technicians, chemists or consultants, are able to identify the real source of this phenomenon, as there is little or no ready evidence of its existence. Even fewer service people do much to either prevent the Biofilm from developing in the system, or offer an effective way of removing it once it has established itself.
In fact, once established, biofilms are incredibly difficult to remove since copious doses of biocides can impact on their surface only. The outer layer of dead organisms then acts to protect and feed the thriving community beneath. This is very like spraying a populous aphid colonisation on a rose bud. The spray will kill only those aphids that are actually exposed to the pesticide, while the inner protected layers will continue to feed off the bud. When these Biofilms develop in pipes we have no way of verifying their existence – and until recently, very little could be done to remove or prevent them.
DISCOVERY CAN BE DIFFICULT
State Health Departments and local government health bodies rarely legislate, act upon, or warn of these dangers in pools, until there is a critical event such as illness from, Legionella, Meningicoccal, Psuedomonas aeruginosa, or Cryptosporidiosis, which attract great concern because of their lethal portent. One way of discovering the existence of a Biofilm in a pool filtration system is by simply removing an inspection opening, or multi- port valve of the filter, and digging a hand into the media. The sand will feel sticky and slimy to the touch. In cases where filters have transparent inspection plates – a close look at the media is a much simpler way of monitoring this development, although immature Biofilms would not be visible to the naked eye. Generally we can assume that the Biofilm is there. How thick and dangerous it is, is another matter.
THE FALLACY OF LABORATORY TESTING
Over a century ago, Robert Koch showed the world how to isolate, study and grow pure cultures of microorganisms. Ever since, microbiologists have, like him, been able to discover, and isolate, the sources of many diseases and develop strategies to prevent contagion. This German Nobel prize winner discovered the source of the spread of Tubercolosis, (amongst others) and proposed ways of successfully eliminating it. The methodology he employed in discovering bacteria and studying them, are still used today in establishing whether or not samples of water taken from swimming pools or spas contain significant levels of pathogens which ultimately render that water unsafe for bathers.
Paradoxically, this has brought about the situation where these testing methods fail to expose the dangers lurking in the Biofilm – because, a sample taken from the pool might give no indication what so ever, of the presence of the millions of pathogens multiplying in this discrete layer. The dislodgment of conglomerates from the Biofilm is haphazard and irregular. Scientists studying Biofilms in air conditioning cooling towers found that 99% of the Legionella Bacteria exist in the Biofilm. One recommended spa decontamination procedure in the US requires treating the spa system with 100 ppm of free chlorine!! We know today that this would probably not dislodge the biolfilm effectively.
A NEW FOCUS FOR SCIENTIFIC RESEARCH
Since the early 1990s, many Universities around the world with Schools of Water Science, or Medical Research, devoted significant portion of their research resources to studies of the Biofilm in such areas as: the water supply, air conditioning systems, on our teeth or in our bodies. Some have even devoted studies to the build up of Biofilm in pools and spas. The Pool Water Treatment Advisory Group (PWTAG) in the UK produced a press release relating to the Biofilm, in 1999, when both a spa at a garden centre, and another at a flower show in Amsterdam – unused by bathers and lacking in disinfectant, contaminated visitors with Legionella.
THE STEALTHY BEGINNINGS OF A BIOFILM
Bathers using warm spas and pools, who neglect to shower before entering the water, contribute body oils, suntan lotion, make-up, hair products, and perspiration, to the poolwater. These materials are all nutrients, which accelerate the growth of the Biofilm. In fact it has been found that bacteria actually feed and breed vigorously in this protective Biofilm environment. As a Biofilm continues to grow, eventually unstable chunks break off into the circulating water stream. These contain huge numbers of potentially pathogenic cells which are quickly dispersed by the pumps throughout the pool. Spas are also equipped with jets and air blowers, which effervesce, and can aerosol infective organsims into the air above, where they can be inhaled by bathers. The vagaries of Legionella are well chronicled under these circumstances. *(Refer to an incident in the spa of the Collingwood Football club in June – July 2000) Pool and Spa owners with repetetive mechanical failures in their circulation, or dosing mechanisms, invite accelerated growth of this menace.
*In this incident footballers bathed in a poorly maintained spa in their club – several contracted Legionair’s Disease.
PROTEINS THAT AID MICROBIOLOGICAL CHEMICAL REACTIONS
All living organisms are composed of a significant proportion of various proteins. These are polymers made up of amino acids, nature ’ s building blocks. Within this group of organic proteins is a sub-group known as enzymes. Enzymes are biochemical catalysts, which control the formation and digestion of virtually all biological molecules. Thousands of these have been identified in living cells. For example, we exhale carbon Dioxide (CO2) which is produced from Carbonic Acid in our blood and converted, with the aid of an enzyme (Carbonic anhydrase), to the exhaled gas, when the blood cells enter the aveoli of the lungs. The enzymes speed up this process to about 10,000 times that at which it would occur without them.
Catalase is a different Enzyme which leaps to the protection of P. aeruginosa when hospital staff try to disinfect instruments with hydrogen peroxide (H 2 O 2) by quickly disarming its potency and converting it to water and oxygen:
2H 2 O 2 >> 2H 2 O + O 2
This enzyme is found in the “slime” emission of P. aeruginosa and can decompose 40 million molecules of hydrogen peroxide in a second.
A NEW METHOD OF BIOFILM REMOVAL
How then can we enlist the aid of enzymes to remove the Biofilm from all of the surfaces of our pools and spas, the associated pipe work, filters, pumps and other equipment which conceal its insidious presence? Many will be surprised to learn that one of the world leaders in the development of enzyme treatments for Biofilm removal has come up with the most successful product available in the marketplace today, known as Multizyme**. That leader of research and development is none other than Novapharm Research (Australia) P/L in Sydney whose active enzyme cleaners are used in hospitals worldwide, to clean surgical instruments after each cycle of use. When the Multizyme formulation is dosed into the pool or spa water, it strips (digests) the Biofilm from all the interior surfaces of the pool or spa plant within hours, by circulating the dosed pool water constantly. [ ** Now known as Aeris Guard ]
Previous products of this nature were unfortunately not successful in removing the built up Biofilm, mainly due to the lack of technology at the time which sustains enzyme activity during the treatment. There are hundreds of enzymes to choose from. Some work at very low pH while others at very high pH. They are quite different to bacteriophages each of which attack only one specific bacteria. In nature each has a very specific task – so we must be thankful that we now have an effective answer for enzymatic Biofilm removal in heated spas and pools and in warmer tropical climates where the Biofilm thrives all year round.
A STRAIGHFORWARD TECHNOLOGY
Within hours of application to a pool or spa the enzymes digest the Biofilm, resulting in very unhealthy water. Clumps of the Biofilm including the slime and other detritus together with the micro-organisms that were entrapped in the pipe continue to circulate until such time as the entire biofilm is released into the body of the pool or spa. In one application of this technology I actually collected samples of the pool water every two hours. After submitting the labeled samples to microbiological tests we found that it had taken 12-14 hours to release all of the bacteria into the water. This conclusion was exposed at the point where the steady increase in the microorganisms (from sample to sample) in the water stopped and we were able to conclude that the process of stripping was complete.
This water must then be dumped and the system briefly flushed out with fresh water, which should then be totally removed from the pool or spa. Biocides such as chlorine and bromine render these enzymes ineffective – so treatment should begin when the free chlorine or bromine residual in the water is very low or non existent. Alternatively, a chlorine quencher such as Sodium Thiosulphate (at the rate of 1 gram / 1000 litres/ 1 ppm of free chlorine to be reduced) will remove the active chlorine from the water – prior to beginning the treatment. If Ozone or UV generators are installed they should be switched off during this process. To be doubly sure that the pool surface is entirely free of contaminants a quick swab of the inner pool surface with liquid chlorine will ensure that no active pathogens remain in the system before refilling.
As the pool or spa fills it is a good idea to dose 3 mg/l of free chlorine (granular or liquid) just to ensure that no live pathogens are still around to start up the Biofilm again.
Regular periodic maintenance treatments would avoid the need for the final flushing with fresh water. In the case of a domestic spa for example, the spa should be dumped every two to three months at the very least, as a regular maintenance procedure. Prior to this, the Biofilm can be stripped as described above. In public spas this should happen as often as the TDS rises to 2000 ppm. In busy places this might happen twice or three times per week, depending on the bather load. In these cases the spa can be dumped early morning before opening after a thorough 12 hour Multizyme – Spa treatment over night, on a monthly basis. The pool or spa must be closed during this treatment for obvious reasons.
Heavily loaded public pools would need to do this exercise at least once a year, while Hydrotherapy and Learn To Swim pools would need two to three treatments per year, to keep them safe. Domestic heated pools should find that an annual Multizyme treatment (during a noliday break) would keep it safe from contamination. Multizyme is pH neutral and does not act as a biocide. Its job is to break down the organic compounds binding the bacteria to one another and to the interior of a spa or pool or the plant surfaces.
Alan Lewis email : email@example.com