Your guide to residential water treatment.
Choosing the right water treatment system for your specific needs.
Since there is a glut of water treatment options in the market place today, it is important that you have the proper information to make an informed choice.
As a well informed consumer, you can minimize the confusion associated with purchasing a home water treatment system. First things first though. The decision automatically gets split into two based upon whether your water supply is from a city water source or a private well.
Municipal Water vs Well Water
If you are on a municipal water supply, then the decision is relatively simple and straightforward. If you are on a private well water source, then it gets a bit more involved.
Municipal (City) Water
Municipal water generally comes down to deciding to’cure’ some taste, odor and hardness issues. Typical treatment options for city water are: water softeners, carbon filters and reverse osmosis drinking water systems. Sometimes, some people feel the need to further refine the taste of the drinking water so a Reverse Osmosis system is added to the mix.
Activated Carbon is considered the workhorse of water treatment filtration. It has an amazing capacity for contaminant removal – approximately one million gallons per cubic ft (45 lbs). It has a high affinity for chlorine reduction, organic compound reduction and greatly improves the taste and odor of municipal water.
It is said that coconut shell carbon gives water a ‘sweet’ taste.
Carbon Filters come in 2 different forms – Cartridge Filters & Granular Carbon Filters.
Carbon cartridge filters are produced in several different sizes. The size of the filter will be related to the flow rate capacity of the filter. The larger the filter, the higher the potential flow rate capacity of the filter. The cartridge is typically contained within a plastic filter housing. Drinking water carbon filter cartridges (point-of-use) are typically 2 1/2′ dia x 10′ ht. Whole house carbon filter cartridges are typically 4 1/2′ dia x 10′ or 20′ ht. Carbon filter cartridges typically have a useful life of 6 to 12 months before they need to be changed. Cartridge filters are nice since they are easy to change.
Granular carbon filters are designed for whole house applications. The granular carbon is contained within a fiberglass mineral tank which typically has an automatic control valve attached to the top of the tank which initiates an automatic backwash of the granular carbon on a periodic basis. This backwash ‘re-classifies’ the carbon which means that new surface area is being exposed to the flow of water. The backwash procedure also purges any dirt or solids from the mineral tank. Granular carbon filters have a very high capacity for filtration. The rule of thumb is that for every cubic ft of granular carbon you can expect 1 million gallons of filtration capacity. A 1 cubic ft granular carbon filter measures 9′ dia x 48′ ht.
Water softening is a ‘balck & white’ treatment process – the actual hardness is removed from the water so either the water will test hard or soft. The resin beads in a water softener tank actually physically remove the water hardness (calcium) from the water. The positively charged calcium ions are attracted to and bond with the resin beads. This process results in the physical removal of the calcium from the water. The affect on the aesthetic and functional use of the water is fairly dramatic. Water hardness creates havoc in many ways – it leaves behind scale deposits and significantly interferes with the effectiveness of cleaning and grooming products.
A water softener will consist of a mineral tank bedded with softening resin, an automatic control valve to regenerate the exhausted resin and a brine tank. A water softener works likes this: water passes through the bed of resin, the calcium ions bond with the resin, the bed becomes saturated with calcium ions, the automatic control valve initiates a regeneration of the resin, the brine solution in the brine tank is drawn into the softening tank and coats the resin beads with either potassium or sodium ions, the calcium ions are dislodged from the resin beads and are washed into a drain receptacle, the water softener is then ready for another service cycle.
Water softening has lost some popularity in recent times due to the fact that it does require salt or potassium to ‘clean’ the resin on a regular basis. This process results in extra salts being deposited into the municipal water supply. The municipalities are then left to deal with this extra salinity to deal with. Just one softener makes little impact in this regard but when you multiply the affect by the total number of softeners in one municipal region, the affect can be significant. Many cities are trying to legislate a ban on new water softeners being installed in their jurisdiction. This has led to new ways of dealing with water hardness that do not require the use of salt.
The No-Salt market has erupted in the past few years. No salt water conditioners are a nice ‘green’ alternative to water softeners but buyer beware. Since it is strictly an opinion based product debate, it is nearly impossible to make a strong recommendation on which type of no-salt systems work best. Since the calcium is left in the water with a no salt system, the results can’t really be tested scientifically – it is strictly a feel thing. The results can only be measured by trial and subsequent opinion. A water softener can be easily tested with an inexpensive test kit and will yield a definitive result on whether the water is hard or soft. The no-salt systems actually do not remove the calcium from the water but alters it in such way to minimize the affects of hard water. By leaving the calcium in the water, the test kits that are employed in testing for hard or soft water do not work for no-salt systems. The unfortunate fact that no salt water conditioners can’t be tested (easily) lends to the suspicous nature of this type of product. It is a fact that the dramatic results experienced with a water softener are not quite realized with a no-salt system. The results are much more subjective in nature,
Although carbon filtration can significantly improve the taste and odor of drinking water, some areas of the country have too high of a mineral content in the water which can create a negative taste in drinking water. Spring water seems to have the ideal level of dissolved minerals – usually ranging between 50 ppm to 100 ppm TDS. Any levels higher than this can cause a salty taste to the water. In order to remove the salts (minerals) from the drinking water, you will have to pass the water through a semi-permeable membrane which is better known as reverse osmosis. Forcing water through a reverse osmosis membrane separates the water (H2O) from everything else. Since RO systems produce water rather slowly, it is required to store the pure water in a pressurized storage tank for proper flow rate delivery. The rejection is sent to the drain system of the house. When drinking water is desired, you simply dispense the water from a dedicated faucet (not your kitchen faucet). When the tank is drawn down to a certain point, the reverse osmosis system begins to make water into the tank to recover the water that has been used. RO water must first be stored since the production rate of most systems is too slow to produce water fast enough to meet flow rate demand. The average useful life of the filters is typically 1 to 2 years (depending on your water quality). Filters are relatively easy to change and a filter/membrane kit should run about $100.00.
If your water source is a private well, then things could get a bit more problematic. Sometime you get lucky with your well water quality and sometimes you don’t.
Iron and manganese represent themselves by either brownish/reddish stains or black stains. Although iron in your water is a terrible nuisance, it poses no health risks to speak of. Any iron content above 0.3 ppm or mg/l will result in iron staining.3 ppm). Manganese is very similar to iron related problems but is a far less prevalent problem as compared to iron. The treatment process for manganese is near identical as compared to iron treatment. When iron is oxidized, it precipitates into a solid (as opposed to a dissolved solid when it is in solution). When this occurs, it can buildup in the plumbing system and plumbing fixtures and cause expensive repair situations. Aesthetically speaking, it could ruin every bit of laundry you own and stain your prize glassware and dishware. Iron staining is not limited to household problems, it can ruin stone masonry surfaces on the exterior of your home as well.
There are several treatment options when it comes to iron. The best choice (in my opinion) is Birm Filtration. A huge advantage of birm filtration is that it does not require any salt or chemical regeneration. Birm acts as a catalyst between the natural oxygen content of the water and the iron compounds. The catalytic reaction serves to precipitate the dissolved iron into a solid which then becomes somewhat easy to filter out from the water. The solid iron particles get trapped in the Birm filter and are later back-washed and rinsed from the filter during the automatic backwash sequence. Birm also treats manganese in the same manner. Birm is pH dependent (6.8 or higher).
Next to iron related problems, hydrogen sulfide odor is also a very prevalent well water problem. It is usually referred to as ‘Rotten-Egg Odor’. The easiest solution for this problem is with the use of Catalytic High Activated Carbon filtration (CAT-HAC). The catalytic property of this carbon filtration media makes it very effective in significantly reducing the affects of hydrogen sulfide odor. CAT-HAC requires periodic backwashing to eliminate any buildup of suspended solids. Although CAT-HAC has a very high service capacity, it must be replaced periodically once all of the available surface area is used-up. CAT-HAC is contained within a fiberglass mineral tank with an automatic control valve attached to it. The automatic control is what initiates the backwash cycle periodically. The water to be treated should be relatively free of solids and oil and the dissolved oxygen content of the water should be 4 ppm.
Nitrates are a colorless, odorless & tasteless compound present i some groundwaters. Nitrates can be expressed as NO3 (nitrate) or NO3-N (nitrate/nitrogen). Nitrate levels above the EPA Maximum Contaminant Level (MCL) of 10mg/l NO3- N or 45 mg/l NO3 may cause methemoglobinemia or blue baby syndrome.
The formation of nitrates is an important part of the nitrogen cycle in our environment. In moderate amounts, nitrate is a harmless constituent of food and water. Plants use nitrates from the soil to satisfy nutrient requirements and may accumulate nitrate in their leaves and stems. Due to its high mobility, nitrate also can leach into groundwater. If people or animals drink water high in nitrate, it may cause methemoglobinemia, an illness found especially in infants. Infants are more at risk from nitrated due to the fact that their stomach acid is not as strong as it is in older children or adults. This causes an increase in bacteria that can readily convert nitrate to nitrite (NO2). Do not let infants drink water that exceeds 10 mg/l NO3-N. This includes formula preparation.
Pregnant women, are also susceptible to the effects of nitrate consumption.
Healthy adults can consume fairly large amounts of nitrate with few known health effects.
Although there is no enforceable drinking water standard for livestock, do not allow animals to drink water with more than 100 mg/l NO3-N. This is especially true of young animals. They are affected by nitrates the same way as human babies. Older animals may tolerate higher levels.
The most effective methods of treating nitrates in your water are Reverse Osmosis and Nitrate Select Exchange Resin.
Reverse Osmosis will actually significantly reject the nitrate molecule from passing through to the drinking water supply. It is rejected to the drain source.Some states offer Nitrate Certified RO systems but most any RO system will significantly reduce the nitrate content of water. It is recommended that you utilize a Thin Film Composite membrane (TFC) and make sure you have at least 60 to 100 psi available to the feed water connection.
Nitrate Select Resin is much like a standard water softener but rather than attracting to calcium to the resin’s surface, it attracts the nitrate molecule. This type of system will treat water to the entire household (vs RO which only treats the drinking water). Once the resin is exhausted, the system is regenerated with a brine solution (sodium or potassium chloride) and the resin beads are cleaned of the accumulated nitrate molecules. The nitrates are carried away to the drain source or septic system.
Water hardness is water hardness whether it be from a municipal water source or private well. However, on a private well, the potential for really hard water is possible. Regardless of the water hardness level, the water softening equipment employed is basically the same, The only difference between moderately hard water (municipal) and very hard water (some wells) is that you will go through much more regenerant (sodium or potassium chloride). This is so because the throughput of a water softener is reduced when the water hardness rises. Thus, more frequent regenerations will be required in very hard water scenarios. Service flow rates must be tightly maintained in very hard water situations. Flow the water too fast through a water softener with very high hardness may result in hardness breakthrough. Moderately hard water is considered to be between 10 to 20 grains per gallon. Very hard water is anything above this level.
High Total Dissolved Solids (TDS) – ‘Salty Water’
Much like water hardness, excessive mineral content can also occur in well water much like municipal water. It is true that some wells may be relatively low in TDS (mineral content) but some wells may be very high. When this is the case, much like the municipal situation, reverse osmosis is the best treatment approach. However, in this case, it typically becomes necessary to treat all of the taps in the household vs. just the drinkng water tap. In order to accomplish, a Whole House Sized Reverse Osmosis System is required. It works pretty much identical to an under the counter RO system but the equipment size is larger and the system produces enough purified water to operate a typical family household. Whole House Reverse Osmosis will produce excellent quality water at every tap but the price tag is typically high – over $10,000 in most cases. Unfortunately, if your well water is very high in a mixture of dissolved minerals, then Whole House Reverse Osmosis is the only solution.
Well, given my experience in the water treatment field, these are pretty much the ‘Usual Suspects’ when it comes to treating municipal & well water sources.
I hope it was helpful.
‘Expert water treatment Guy’
Your Guide to Residential Water Treatment – How to choose the best water treatment system for your needs.
- What is Rapid Sand Filter? (poolfiltration.net)
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