AFM and swimming pools, some FAQ
What is AFM?
AFM is a filter media manufactured from green container glass. The glass has been purified, heated to over 1000 deg C and then reduced in size to a very specific particle size and shape. The glass is then treated by a two stage chemical and third stage thermal process to produce an activated mesoporous surface which is 300 times greater area. The surface can adsorb organics such as chloramines and particles down to 1 micron
How is AFM superior to sand , zeolite and other forms of glass?
AFM filters 97% of all particles in the water down to 5 microns at a water flow of 20m/hr, sand achieves 72% so in terms of what is left in the water, 3% for AFM and 28% for sand, AFM is almost 10 times better than sand. The mechanical filtration performance of zeolite and all crushed glass products tested by independent analysis confirms that AFM is best followed by a good quality silica sand.
The biggest problem in swimming pools and spas is ammonia. Ammonia introduced into the pool by bathers in sweat and urine. How well will your product cope with this major problem?
Nitrogen input to pools is 9% ammonium 85% urea and the remainder is creatine, amino acids and peptides. AFM does not support the growth of bacteria. Sand filters, zeolite filters and to a lesser extent crushed glass filters become biofilters. Urea is converted to ammonium by urease bacterium enzymes. The extra ammonium produced is under the acidic conditions on the surface of biofilms. The ammonium almost instantly reacts with chlorine to forms trichloramine. This does not happen with AFM, so all AFM pools will have virtually no smell, and bathers will not complain of sore eyes. However there will be a organo-chlorine such as chlorourea, so total combined chlorine may remain the same. This is why we introduce APF coagualtion with ZPM in order to remove the dissolved organics.
Will the use of AFM reduce chemical costs?
Yes because there is an improvement in filtration, the chlorine oxidation demand of the water will be reduced by 50% to 90%.
What effect will AFM have on chloramines such as mono, di-chloramine and tichloramine?
The inorganic chloramines will be reduced by 80% to 90%. In addition the production of THM's and cyanogen chloride will also be reduced.
Grease from makeup, sun tan oil, deodorants, causes some filter medias to become ‘mud balls’ What effect will this have on AFM?
Mud balls are primarily caused by bacterial coagulation as opposed to sun tan oils and other cosmetics. Bacteria coagulation and mud balling will happen in many sand filters, especially if the filter is of a poor design and is not managed properly. It is really important to fluidise the bed by at least 20% on a back-wash.
It is stated that AFM will pay for itself within a reasonably short time, How is this achievable?
Chemical, energy, media replacement and water savings. Reduction in chlorine and acid by 50% to 90%, reduced pumping energy and requirement for ventilation, AFM never needs to be replaced and we can reduce the back-wash water requirement by up to 50%. Independent life cycle cost analysis confirms an ROI ranging from 6 to 18 months.
With sand filters it is recommended that weekly back-washing should take place, is it the same for AFM.
AFM should be back-washed on a weekly basis for a minimum time frame of 3 minutes.
How long will AFM last, how often will it need replacing?
AFM will last for the life of the filtration system, technically it never needs to be replaced. Sand deteriorates with time, AFM actually gets better with time. If AFM is removed from a filter, Dryden Aqua will pay for the delivery of old AFM back to Edinburgh. We will reprocess the media and use again.
What effect will AFM have on water clarity?
AFM will usually double the clarity of the water. Turbidity is caused by dead bacteria and bits of bacterial cell biomass. Dead bacteria are almost as dangerous as living bacteria. AFM when used properly will reduce turbidity to under 0.05NTU which is equivalent to more than 25meters of clear visibility through the water. If you have essentially zero turbidity then you also remove cryptosporidium oocysts that are the main reason for disease out-breaks from pools.