When designing a pump room there are many things to consider and none of which are typically set in stone either. Indoor versus outdoor facilities have different requirements and needs and most of the time it is much more difficult to design an indoor facility… properly. We're going to give you in order some of the most important aspects to consider and give you an explanation as to why.
Essentials to Designing a Pump Room
Filter it FAST!
One of the first and most important factors in designing a pool system is the turn-over-rate (TOR). The TOR is the amount of time it takes for all the water in the pool to circulate through the filtration system. This is one factor that can separate a good pool design from a great pool design. For example, a TOR of one hour for a 100,000 Gallon pool means that about 60% of the water is filtered every hour. Keep in mind this is a statistical number that is giving a general idea of how much water could actually be filtered in that time taking the dilution factor into account. So, if there were some unwanted microorganisms present in the water brought in by one or more of the many bathers’ present or by some other means, we can expect that 60% of the water to see the filter system every hour. Most pools have an average of 6 - hours for a TOR, which completely changes everything. So, from the same view it would take 6 hours for 60% of all the water in the pool to be filtered. That’s a big difference when you consider that there may be anywhere between 1 – 50 new bathers being introduced into the water every couple hours. In turn that means that the TOR extends another 6-hours every time new bathers are introduced. If you compare it to the 1-hour TOR, there really is no comparison since 60% of the water is being filtered every hour of the day vs every 6-hours.
A great TOR means that the system can quickly FILTER the water in 1- hour-- not disinfect or oxidize it, but just filter it. Keep in mind microorganisms are very small, as small as 4 microns in some cases and some of the most common filter systems only filter down to 25 microns, some only at 10 microns, and a small percentage at 4. What does that mean for these microorganisms? It means we have a highly efficient way of spreading them quickly throughout the entire pool!
Greater Filtration Area!
Great filtration is key to keeping your pool crystal clear for any occasion. What we mean by any occasion is that time during that particular week, weeks, or month when your pool is at breaking point with the maximum number of bathers under the hottest time of the season. That's what you prepare for in the first place! It's these times that aquatic managers and staff start stressing on how to be better prepared. It’s almost like preparing for competition and you’re not sure whether or not you are truly prepared to win.
The slower the flow through filtration the greater the removal rate of unwanted dirt and debris in the water. This is known as the “filter media rate". This is how fast the water moves through a given type of filter media. Take for example a raging river: is it clean or dirty? Most likely its extremely dirty! Compare that with a trickling stream. Is the stream clean or dirty? Streams are most likely very clean and clear. We already know that mother nature is a pro when it comes to filtering water. Those streams and springs you see coming out the side of mountains that are sometimes so crystal clear and clean we can drink it right from the spot. How many types of media, and how deep do you think that water traveled to get that clean? Probably more than you could ever imagine!
How do we try to mimic mother natures way of filtering water? We add more filters and make them deeper than the standard 24” bed depth. More filtration means that there is more surface area of filter media to take out particulates from the water. It also means that the dirt and debris are less likely to be driven into the filter media bed that can later lead to channeling. Adding more filters lowers the filter pressure, reduces stress on the filters, reduces stress on the pump, and can allow for isolation. Ultimately, it can also increase the life expectancy of the equipment due to the reduction in stress.
Most sand filters on the market today offer a bed depth of about 24” on average. It doesn’t matter if they are the large commercial horizontal filters or the small round filters you so often see at hotels, HOA’s, and commercial facilities. When you change the bed depth to almost twice the standard you can also increase the amount of particulates that are removed from the water as well. When you get the opportunity to visit a pool with a properly sized deep bed sand filtration system with a bed depth of 40 + inches, it’s a truly impressive sight.
Finally, the last item for filtration is the type of filter media used to remove unwanted dirt and debris. The standard #20 silica sand that has been used for years has proven to do a good job and provide some good water quality. We also know that over time it can channel and wear out from backwashing. There are other types of filter media available on the market that can provide a much higher level of particle removal than the standard sand. Glass media, zeolite, perlite, and ceramic are the next levels up from sand. When filtration is properly sized the chosen media can make a huge difference in water quality at many levels. Furthermore, there is yet another layer that can be added to filters such as flocculants like alum and Poly A tabs. When properly paired with enough filtration your new level of filtration could be as low as 1.5 microns! That’s a huge difference when we look back at the average pool being only at 25. However, not only does this mean a smaller particle removal rate but also the removal of those dreaded harmful microorganisms that could be lurking in your water as well.
Now let’s do a short review of what we have already created. We now have a TOR of 1-hour, filtration area large enough to handle the fast-flowing water, and filter media dense enough to filter down to 1.5 microns. We are now ready to handle the large bather loads whenever they arise and be rest assured that 60% of our water will be highly filtered every hour on the hour 24/7. I already feel much safer with this fictitious pool!
Disinfection to the Limit!
Disinfection is next in line in creating an effective and efficient pump room. As we mentioned earlier, if we can quickly filter the water, we don’t want to spread those unwanted microorganisms throughout the pool. Instead we want to be able to kill ALL or at least the vast majority of them that pass through the system.
Let’s first start with what a standard system looks like and how it works. Most pools have some sort of chlorination system that provides a residual amount of chlorine in the water that is typically around 3 PPM. This residual chlorine is meant to disinfect and oxidize the vast majority of contaminants as they’re introduced into the water. However, when you’re dealing with tough chlorine resistant organisms that can live for days in the pool, such as Crypto, it doesn’t seem to be so effective anymore. Unfortunately, the only way we find out about this unwanted microorganism lurking in the water is when someone gets sick and goes to the doctor to identify it. Microorganisms are not something you can see with the naked eye and can’t be tested for at the aquatic facility either. We must prepare our systems as best as we can to prevent them from transmitting to other bathers present in the water. The question is, how do we do that” efficiently and effectively?
There are several secondary disinfection systems available on the market today. Some more effective in one way or another than the other. There are ozone systems, ultraviolet systems with both low and medium pressure, oxygen systems, and magnets just to name a few. Did you know that all these elements are utilized by mother nature in some way or another? All of them are part of a natural way of disinfecting water, but none of which are capable of doing all they work alone. We just need to understand the sequence of how these systems are used and the benefits each provide.
Ozone is one of the strongest disinfectants and oxidizers available on the market today and is a natural element. It can be 20 – 3000 times stronger than chlorine alone and can KILL the toughest of organisms very quickly with the right dosages. Since most ozone systems are designed to run 24/7 they provide an excellent layer of protection to our bathers. It can kill one of the toughest microorganisms like Crypto in 3-minutes or less depending on dosage. Going back to our 1-hour TOR, as the water continuously runs through the pump room we know that 60% of the pool is being disinfected and oxidized every hour of the day. That’s pretty good when you think about Crypto being capable of lurking in the water for days with just chlorine as a primary disinfectant and your average 25-micron sand filter allows its safe passage each and every turn-over. Keep in mind Crypto is only 4 microns so when we look back at our average filtration systems they do a great job of spreading this little bugger all around our pool without harming or removing it!
UV (ultraviolet) systems can be a great addition to the pool. When properly sized for flow they can sterilize Crypto and prevent it from reproducing. It doesn’t kill the microorganism, but it does keep it from harming people. UV unfortunately does not provide any oxidizing power and can be hindered from poor water quality. As the day gets hotter and more and more people come in and out of the water it can become cloudy and hinder the effects of UV systems. Lotions and oils in the water will and can also hinder the UV systems from fully penetrating the water to sterilize these microorganisms as well. More powerful medium pressure systems, without proper controls, can burn off chlorine and increase operational costs. Low pressure UV systems have a smaller wavelength of light, but do not burn off the chlorine in the water and can have a lower operation cost when properly sized. This is why we talked about filtration first and that it is the foundation of building an efficient and effective pool system. UV does however treat 100% of the flow that passes through the pump room. This is important to understand when we go to the next items on the list.
One of the newest systems on the market is “Hyper Dissolved Oxygen” systems known as AquaGen. This system takes 97% +/- pure oxygen and diffuses millions of Ultra Fine Bubbles, AKA Nano bubbles, into the water increasing the dissolved oxygen content. Most bodies of water contain anywhere from 6 – 8 ppm of dissolved oxygen depending on water balance, temperature, and elevation. This system can crank the water up to as much as 30+ PPM of oxygen and keep it in the water for days at a time. Oxygen by itself is a mild oxidizer and disinfectant, so the extra millions upon millions of oxygen can assist with the disinfection and oxidation process as well. Not to mention it is yet another level of residual in the pool to help with the entire treatment process. When used in conjunction with low pressure UV systems it can provide an even greater benefit as it passes through the pump room. Some low-pressure UV systems utilize 185nm of light which in turn creates ozone. Some manufacturers design these systems with this specific wavelength of light to further enhance the UV’s capabilities by creating a little bit of ozone from the normal oxygen levels (6 – 8ppm) present in the water. However, when there is an AquaGen on the system you have 2 – 4 times the ozone being created from the same UV because of the heightened amount of oxygen present.
We’re not done quite yet though. There is one more process on the list that raises the bar to extreme levels above the norm. The Advanced Oxidation Process (AOP) is a method of running ozone through the UV system. When properly sized this methodology can destroy just about anything that passes through the UV system. When ozone passes through the UV chamber it creates what is know as “Hydroxyl Radicals.” These radicals are extremely reactive at destroying both organics and microorganisms very fast. As they pass through the chamber there are millions upon millions of reactions taking place in fractions of a time. Since these hydroxyls are so short lived they are not carried back to the pool to continue the process. They only work as the water carries the ozone through the UV system.
Our fast TOR, large filtration area, dense filter media, and strong sanitizing systems have pretty much left us with, and sometimes better than, drinking water quality in our swimming pool. We know that every hour 60% of the water is being rid of and completely sanitized of any microorganisms that could be present. This is 100 times better than super chlorination used to treat for Crypto after an outbreak. Regulation for Crypto treatment is raising the chlorine level to 20PPM for 12.75hours to have a 99.9% kill rate. However, with a TOR of 1-hour means that 99% of the pool will be rid of this bugger in just 4 hours. Sure, we could kick it up a notch for safety and say 6-hours just to be safe. Don’t forget that just because you raised it to 20 PPM and left it there for almost 13-hours means that you destroyed this little pest. Those that use stabilizer or Cyanuric acid in the water hinder the chlorines effectiveness greatly depending on the level present. It could take two or three times the level of chlorine and time to completely rid this nuisance.
This pretty much sums up the most important part of building a highly effective and efficient pump room system. It doesn’t however include the remaining controls and balance systems to help operate this masterpiece. That’s a completely different topic that we’ll talk about in the next section.