There is little doubt that the La Ventana and El Sargento Municipal (SAPA) water is both interesting and "challenging" to a water treatment and conditioning company.
In the USA the permitted and regulated amount of TDS (Total Dissolved Solids) in Municipal Water is 500 ppm (parts per million). In Mexico this, largely unregulated level, is 1,000 ppm, and, of course, nobody is there to regulate the Regulators. In most of BCS the level ranges from 500 ppm to 850 ppm TDS, as is the case in La Paz.
In La Ventana the level is around 3,250 ppm TDS. This is a result of sea-water intrusion into the local Aquifers located in Los Planes. In addition there are trace amounts of naturally occurring Arsenic plus possible additional Arsenic and Cyanide coming into the local water table from nearby Mines. The Municipal water is also high in TSS (Total Suspended Solids) which include the pathogen family of Virus, Bacteria, Cysts and Algae. Problems are compounded by the high winds and unpaved roads which cause copious amounts of sand and other debris to swirl around and, as we are sure that people are aware, sand gets in anything and everything, including underground Cisternas and roof-top Tinaco's.
Finally the water is extremely hard, because of high amounts of calcium and magnesium that abound in the local desert soil. This result is around 25 grains per gallon of hardness and, by comparison to the USA, 5 grains per gallon is considered hard.
We have the capability of removing anything from water, but this always comes at a cost….the challenge of treatment and conditioning is to balance the capital cost with the running cost. Consequently, we have spent over 5 years developing a water treatment system that incorporates fully certified, State-of-the-Art technology, that is not readily available in Mexico.
Whole house RO (Reverse Osmosis) for around 200 to 250 gpd (gallons per day) of Permeate water is both expensive and extremely wasteful of water, a precious commodity down here. For the Brackish water of La Ventana one can expect around 10% to 20% recovery i.e. requiring feed water of between 1,000 and 2,500 gpd with between 800 and 2,250 gpd going to waste. This has a high cost implication as has the electrical energy to pump 1,000 to 2,500 gpd of feed water at around 250 psi through the system and R.O. membranes. New technology incorporating a wind generator, solar panels and a new RO 48 VDC High Pressure Pump delivering 30% recovery is also now available, although the capital cost will be prohibitive for most people.
Our recommended solution therefore, is a 5-stage filtration & conditioning system:
1. The placement of a sand filter before the Cisterna or Tinaco (we assume that people have a hydro/pneumatic Pump and Tank that delivers the water around their Casa and that they do not rely on a gravity-feed roof-top Tinaco). This special filter pushes the water through a 250 mesh screen (around 60 microns) in a circular process that allows the sand and any other suspended solids, that are heavier than water, to drop to the bottom of the filter where there is an on/off valve which can be opened for a few seconds every week to flush out the collected debris. People will be amazed at the amount of sand etc which is collected by this filter.
2. We would follow this with a 20 micron Pleated Sediment filter which can be rinsed out once a month or as required.
3. This would be followed by a proprietary Blue Angel whole house filter with a 5 micron washable Sediment Pleated Filter similar to the first filter in the first Filter Housing. This would be followed by a 0.1 micron double-wrapped, with Nano-Silver (Ag+), Argonide™ Nano Ceram Filter with a carbon block center core (as developed for the US NASA Space program and used for purifying drinking water in the Space Shuttles and on the International Space Station).
4. Finally, the 3rd Filter Housing contains a "ScaleStop™" media cartridge which crystallizes the Calcium & Magnesium Ions. Eventually a sub-micron crystal breaks free from the ScaleStop media and in this form the crystals cannot cause scale deposits. At this stage the water entering your Casa will be virtually free from TSS and accord full protection to household appliances including Washing M/C, Dishwasher and Hot Water Heater or Boiler. People will experience excellent quality showers and will soften the skin and hair. In addition, the water will deliver soft and fluffy towels and other fabrics, greatly enhancing people's lifestyles. On human consumption the crystals will convert back into "highly beneficial" Calcium and Magnesium.
The treated and conditioned water will be pathogenically safe to drink. However the vast majority of the TDS will still be in the water. In general terms this is not a problem although, according to the sensitivity of one's palette, some people may detect a salty taste.
5. Consequently, we would recommend the installation of an additional under-sink system to treat all of the water for cooking and drinking and ice-making. This is a new technology system, specially developed for us by Charles "Chubb" Michaud of Systematix in Southern California. You will see Chubb's profile in our website (www.aguadebaja.com). Chubb is one of our Technical Directors and is universally considered by the US Water Treatment and Conditioning Industry (WQA) as being "the Master of us all".
This system removes all Heavy Metals and Arsenic and has an RO membrane to remove 95% of the remaining TDS including the sodium. The system is monitored and will automatically shut-down after 3,000 gallons (around 2-3 years of average usage). The water from this system will be almost pristine and taste excellent. When installed we can test the water and see if any pH adjustment is required or if there is a need for an additional "ionizer" cartridge.
The whole system, professionally installed, will cost US$3,250.00 plus 11% IVA. The running cost (basically replacement filters) will cost around US$1.25 to 1.75 per day, dependent upon occupancy levels and amount of water consumption. The system has minimal water wastage, requires no chemicals or added salt and no additional electricity. It really is a totally Green" solution.
We apologize for this long report, but as we said at the start, the La Ventana area Municipal water is "challenging". Please feel free to e-mail or call me for any further information or clarification that may be required.