swimming pool water treatment manual

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Swimming pool water treatment manualand elimination chlorine reaction products

No sore eyes and clean clear water, every pool should be like this, a safe place to play and exercise

Benefits of AFM 80% reduced chlorine consumption Cryptosporidium control Reduced bacterial risk Solids removal down to sub micron levels Lower THM levels Reduce or eliminate trichloramines Life cycle cost benefits, water & energy give a return in capital in under 18 months 100% environmentally sustainable

A water filtration project for Life & the Environment. Support by the European Commission LIFE 02 ENV/UK/000146 AFM Dr.Howard Dryden Dryden Aqua 2007 Revised 3/4/09

Application for AFM Drinking water Tertiary treatment of sewage effluent Industrial waste water and grey water Swimming pools Desalination pretreatment Cooling towers Public aquaria

AFM filtration of swimming pool and Spa water, THM`s, trichloramine and water quality problems solved. Public health protected, asthma & respiratory related health risk reduced.


Water filtration in Swimming pools & spasIn recent years there have been many reports in the press regarding trichloramine and its potential implications as a precursor for causing occupational asthma and asthma among children in swimming pools, spas and sports centres. However, as yet there has been no published mechanism why trichloramine is produced or any means of solving the problem. In addition to Trichloramines, THMs (chloroform) is also of concern because of the highly carcinogenic nature of the chemical and its ability to rapidly enter your blood stream via your lungs. Equipment such as Ultra Violet disinfections and ozone systems are now being advocated, however in many cases this technology can actually cause the problems. Swimming is an ideal exercise which should be encouraged, as long as the water quality and atmospheric conditions above the surface of the water are not detrimental to health. This report covers the source of the chlorine reaction products and for the first time their mechanism of production and a solution to the problem. In effect we give a way forward and strategy for the entire swimming pool industry.

Trichloramine production and bacteria levelsChloramines are formed in water by reaction between ammonia and chlorine, the reactions are pH and concentration dependent, the following equations are taken from German DIN standards 19643.H3O+ + NH3 (bacterial mineralisation decomposition of urea from urine, sweat, etc.) NH4+ + H2O NH2Cl monochloramine......................................................... pH 4 to pH 10 NH3 + Cl2 NH2Cl + Cl2 NHCl2 dichloramine .............................................................. < pH7.2 NCl3 trichloramine ............................................................. < pH4 NHCl2 + Cl2 NHRCl alkylmonochloramine NH2R + Cl2 ( denotes a reversible (equilibrium) reaction; denotes a forward reaction.)

It is important to note that dichloramine, trichloramine and organochloramine (alkyl-monchlorammine) reactions are not reversible. Once the condition exists for their formation, their concentration will continue to increase unless the chemicals are destroyed or removed. Coagulation followed by flocculation and AFM filtration will remove them from the water. UVc and Ozone will oxidise the chemicals but will form volatile THMs and nerve toxins such as cyanogen chloride. The only safe route is coagulation, flocculation and AFM filtration. The primary source of ammonium in swimming pools is the mineralisation of urea (NH2)2CO, amino acids and proteins by bacteria. UVc and ozone will also crack organics and release ammonium into the water. With AFM systems using good filtration, NoPhos with coagulation and flocculation but without the use of UVc or ozone, you do not actually form ammonium and the chloramine level is extremelyDryden Aqua Ltd | Butlerfield | Bonnyrigg | Edinburgh EH19 3KQ | Scotland UK | Tel +44 (0) 18758 22222 Fax +44 (0) 18748 22229 www.AFM.eu LIFE 02 ENV/UK/000146 AFM

AFM filtration of swimming pool and Spa water, THM`s, trichloramine and water quality problems solved. Public health protected, asthma & respiratory related health risk reduced.


low. Dichloramine and trichloramine essentially do not exist, however the DPD3 reagents used to test for combined chlorine suffer serious interference from alkyl ammonium chloramine groups and as such the reading for inorganic combined chlorine can be out by as much as 90% reading too high for AFM systems in comparison to a sand filtration system. Sand filters operate as bacteriological filters, bacteria growing on the sand will remove the dissolved organics from the water and generate ammonium from the urea. The bacterial biofilm also has a low pH and this is the zone in which trichloramine if formed. Sand filtration systems will therefore tend to operate with a lower dissolved organic content but much higher combined chloramine concentration. AFM removes organics by adsorption, similar to the reactions found with activated carbon, however most of the organics and urea are removed by coagulation, flocculation and then mechanical filtration by the AFM media. Coagulation and flocculation is therefore very important with AFM systems. The added advantage is that good coagulation and flocculation followed by AFM filtration will provide a much more robust form of filtration and will not allow cryptosporidium oocysts to pass.

Combined chlorine analysisDPD2 reagents are specific to mono-chloramine and do not suffer the same interference experienced by DPD3 reagents. Total combined chlorine equates with approximately 1.4 times DPD2 (monochloramine) concentration when using sand filters. For AFM filtration systems because dichloramine and trichloramine levels are very low, the total combined chlorine level equates with 1 times DPD2 monochloramine concentration. Interference from organics and surfactants brings DPD3 analysis into question for swimming pool water, however DPD3 is still a useful analysis to perform, and the results just have to be looked at from a different perspective. If DPD2 gives an under estimate of combined chlorine as measure by DPD3, and there are no smells of trichloramine or sore eyes among the bathers, this means that there are high levels of organics such as surfactants, protein and amino acids in the water. In this situation DPD3 DPD2 result equates with organo-chloramines and interfering chemicals such as surfactants in the water. The following table relates to the key aspects that will cause DPD3 to over-estimate the combined chlorine level. Organo-chloramines are large non volatile and non toxic dissolved molecules. This means that organochloramine molecules will not leave the surface of the water as such they cannot be absorbed through you lung tissue nor enter your blood. Organochloramines therefore do not cause a problem. Surfactants from soap and cleaning agents on the other hand are a more serious issue, the chemicals will prevent coagulation and flocculation reaction from working properly prior to filtration. This means that the public could be put at risk from a plug of bacteria or cryptosporidium oocysts being dumped into the product water after the filters. The surfactants can stop the coagulation and flocculation reactions working properly, the chemicals can also break up the solids on top of the filter, be it sand or AFM, and allow the solids to pass through the filter. Any cleaning agent that contains surfactants, especially anionic surfactants should not be allowed in any swimming pool building. There are even anionic pool products that are being added to the water, such a situation has the potential for being very dangerous. Only use, filter media, equipment and chemical products that have been certified safe and proper.

Dryden Aqua Ltd | Butlerfield | Bonnyrigg | Edinburgh EH19 3KQ | Scotland UK | Tel +44 (0) 18758 22222 Fax +44 (0) 18748 22229 www.AFM.eu LIFE 02 ENV/UK/000146 AFM

AFM filtration of swimming pool and Spa water, THM`s, trichloramine and water quality problems solved. Public health protected, asthma & respiratory related health risk reduced.


Key points that may cause high organo-chloramine levels in AFM systems as measured by DPD3Problem high water flow rates through the filters no coagulation or flocculation incorrect injection point for APF incorrect injection point for chlorine Solution reduce water flow through the filters to less than 15 m/hr start APF coagulation at 1 ml of APF per cubic metre of water filtered per hour inject between the pumps and the filters, directly into a ZPM unit or static mixer inject chlorine after the filter (never before the filters)

for a typical public pool the turn over rate is 4 hours through the filters, for a private pool this may be 6 hours. If the turn over rate is too slow water quality will deteriorate in the pool. Turn over rate through the filters should be appropriate for the installation, however slow turn over rate it is also a good idea to recycle the water the water around the filters and through the pool and a ZPM unit at a higher rate. The simple action of moving the water actually improves water quality and insure a more stable chemistry. what goes into a filter must come out again or the organics retained by the filter will react back-wash filters at with the chlorine and be digested by bacteria. It is recommended that you air purge for 5 correct flow rate minutes at 95 m/hr prior to a back-wash. Back-wash frequency should be at least once a week at 45 m/hr for 2 to 5 minutes. For private filters the air purge is not necessary. all bathers must shower before entering the pool, oils soap, sun tan lotion etc etc must be the bathers removed for hair and skin, this is very important do not use surfactants, a


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