There are 326,000,000 cubic miles of water on this planet. With more than 50 billion gallons per person available, we must ask “where’s the shortage?” There is no shortage but water is not distributed evenly to all regions of the planet. Over 99% of all water on Earth is either seawater or ice and what little there is left needs serious treatment to make it useable for human existence.
Because of water’s unique polarity, it is an excellent solvent. A little bit of everything it touches becomes dissolved in it. While this is an essential property of water, it also explains why water becomes so easily contaminated as it makes its journey from place to place.
Where do water contaminants come from?
Water, passing through the atmosphere as snow or rain, picks up carbon dioxide (CO2) and other acid gases and reaches the Earth’s surface as a weakly acidic solution (CO2 + H2O to H2CO3). As this water soaks in, it passes through various strata containing limestone (CaCO) which neutralizes the acid forming a soluble calcium bicarbonate salt (H2CO3 + CaCO3 to Ca (HCO3)2 which then dissociates into ions. (Ca++) ions with a plus 2 positive charge becomes a cation and HCO3- with a single negative charge becomes two anions. This is how calcium (and magnesium) end up in your water supply. We know these waters as “hard” waters.
Organics from natural decomposition of plant materials as well as carelessly disposed of man- made materials also find their way into ground and surface waters. Treatment of these waters with chlorine and other disinfectants may form a whole new family of compounds and many of these organics are toxic (known as tri-halo methanes or THMs). Often, industrial waste from plating or chemical manufacturing will find its way to streams and eventually to the water supply. Heavy metals such as chrome, lead and copper must be reduced as should be arsenic. Nitrates from agricultural run-off and field drainage are very damaging to infants and the elderly.
Finally, raw water will contain suspended solids which make the water colored or cloudy. Although not all cloudy water is harmful, water haze is often a sign of microbial growth and organic decay which not only tastes bad but can be harmful. Broken sewer pipes can leak raw contaminants into the ground where leaks in water lines can pull them in. Distribution systems must be very well maintained to be reliably safe from cross contamination with sewage.
How are these contaminants best removed?
The traditional treatment for suspended material in water is filtration. All municipalities do some form of filtration to improve the clarity of water and remove certain harmful inorganics, organics and microbials. Following filtration, water must be disinfected, usually with chlorine or ozone to rid it of live bacteria, virus and cysts.
Often, activated carbon may be used to adsorb organic byproducts from the chlorination procedures and then the water must be specifically treated to remove harmful inorganics such as heavy metals and arsenic. Municipally supplied water is generally not treated at all for scale causing hardness or high dissolved mineral.
What problems can unfiltered water cause me and my family?
Unfiltered water might well have an off taste and odor caused by the presence of inorganic and organic constituents as well as bacteria or algae. Even if the water tastes good enough to drink, it might not be safe. Many contaminants have no taste or odor. The World Health Organization as well as USEPA has established standards called Maximum Contamination Levels (MCLs) which serve as guidelines for safe water. The only way to make sure your water is safe is to have it tested by a competent laboratory with certifications for accuracy.
Water hardness is not toxic. In fact, the minerals are considered beneficial for human health. But when hard water is heated, the Ca(HCO3)2 decomposes to CaCO3 and evolves CO2 gas and H2O (water). CaCO3 is insoluble and deposits on the surfaces of water heaters, boilers, coffee makers, pipes and in fabrics, creating a hard scale (known as calcite, lime scale, boiler scale or hardness scale). Scale is a poor conductor of heat so it takes more energy to heat water if the heater has scale. Scale can also clog pipes and appliances and reduces the life of fabrics due to its abrasive nature. In addition, even the soluble calcium and magnesium salts will react with soap causing the familiar bathtub ring and soap scum. Needless to say, it is often desirable to remove hardness ions (or otherwise control them), before using the water in residential or industrial applications.
Water hardness is usually reported in grains per gallon or parts per million (mg/L) as calcium carbonate (CaCO3). There are 17.1 mg/L as CaCO3 equal to 1 grain per gallon (gpg). The term CaCO3 defines a convention representing the number of molecules to be exchanged. The water analysis is usually presented in mg/L (as the element) which has to be converted to ppm (parts per million) as CaCO3 using conversion factors. The factor for Ca is 2.5. You then multiply the mg/L by 2.5 to get ppm as CaCO3. For Mg, the factor is 4.1. Once you have the hardness calculated you add them to get total hardness (as CaCO3) and then divide by 17.1 to get grains per gallon. Water with less than 1 grain per gallon (gpg) is considered “soft” and does not exhibit many of the negative properties of “hard” water. Water above 3 grains is hard enough to produce hardness scale and interfere with sudsing while washing clothes, dishes or bathing.
What are the best methods of treatment for typical problem waters?
To duplicate municipal systems for providing safe drinking water, a water treatment device must (1) clarify, (2) disinfect and (3) remove all contaminants reported above the MCL listed for the specific contaminant. This is very difficult to do with a single technology. Therefore, multiple proven technologies must be employed. In addition, once safe water is provided, it is still advisable to treat that water further to (4) reduce scaling tendencies a, (5) improve the taste and (6) reduce its salinity when necessary.
Water clarification usually involves only a filtration step along with a coagulant to make it more efficient for retaining sub-micron particles. Chemicals are injected to flocculate fine sediment and form larger particles that are more easily removed with typical filtration systems. Chlorine or ozone may be used along with filtration to rid the water of live micro organisms. Then the water is treated for specific contaminants such as arsenic and nitrates. Water that is high in salt (TDS) is usually blended with other sources to reduce so the water does not have a salty taste. Although safe to drink, water will have a more refreshing taste if the salt content is reduced to below 300 or so ppm.
One common method of treatment for hardness is the use of ion exchange systems. Here, the divalent hardness ions are exchanged for non-scale producing monovalent ions (such as sodium or potassium) by passing the feed water over a bed of ion exchange resins.. Although very effective, this method of treatment has come under much fire in the draught stricken sections of the western USA because it adds considerable salt to the discharge which eventually finds its way back into the water table and deteriorating its quality.
Sequestering agents such as polyphosphates can be added to cold water to inhibit scale formation. This is best done with commercial and industrial systems not intended for human consumption since high phosphates can be upsetting to the digestive system. Magnetic devices claim to control scale but none have passed any scale control standards designed by internationally recognized third party testing agencies. Would be buyers of such devices should rely more on scientific proof of performance rather than anecdotal accounts reported by users.
Designing Solutions for Baja California Sur (BCS)
Cost-effective solutions need to be designed for specific water conditions, which may vary from region to region. The Municipal delivered potable water of BCS is a typical example. They tend to be extremely hard (around 15 grain) and can often contain higher than recommended concentrations of heavy metals, particularly Arsenic and Vanadium. Nitrates can also be present. In addition, pathogenic contaminants can be present which can lead to severe bouts of the infamous “Moctezuma’s revenge”. Invariably, these enter the water supply, via leakage and cross contamination from the returning sewerage lines during the distribution train, especially when the water supply is not running due to shortages or rationing.
Obviously water softeners are not a recommended solution as the returning salt discharge will be a nightmare for the much-maligned and under-funded BCS water utility companies. Uncertified magnetic solutions will not work.
Consequently, H2O Profesionales Internacionales, S.A. de C.V. has developed and designed a cost-effective solution incorporating hitherto unavailable State-of-the Art and Space-Age technologies. This has led to the birth of the Blue Angel Combo’s.
Typically, Reverse Osmosis (R.O.) under-the-sink systems for Bottled Water quality drinking water will waste far too much water in BCS and expert guidance is required before you select one of these products to ensure that water wastage is kept to a bare minimum, or a solution designed-in to re-use this most precious resource. The expert consultants at H2O Profesionales Internacionales, S.A. de C.V. will guide you through these choices.