Purified Water is Water that has been mechanically filtered or processed to remove impurities and make it suitable for use in several commercial and residential applications. Distilled water has been a common form of purified Water but Water is more frequently purified by other processes including deionization, reverse osmosis, carbon filtration, microfiltration, ultrafiltration, UV Oxidation, and EDI.
Combinations of a number of these processes have come into use to produce water of such high purity that its trace contaminants are measured in parts per billion (ppb) ot parts per trillion (ppt) purified water has many uses, largely in the production of medications in science and engineering laboratories and industries, and is produced in a range of purities. It can be produced on site for immediate use or purchased in containers. Purified Water in colloquial English can also refer to water which has been treated to neutralize but not necessarily remove contaminants considered harmful to humans or animals.
Deionized water is a type of purified water with mineral ions (salts) removed. These mineral ions include sodium, calcium, iron, chloride, and bromide. Deionized water is created by taking conventional water and exposing it to electricilly charged resins that attract and bind to salts, removing them from water. Because most of the impurities in water are mineral salts, deionized water is mostly pure, but it does still contain numerous bacteria and viruses, which have no charge and therefore are not attracted to the electrified resins.
Granular Activated Carbon (GAC) is commonly used for removing organic constituents and residual disinfectants in water supplies. This not only improves taste and minimizes health hazards; it protects other water treatment units such as reverse osmosis membranes and ion exchange resins from possible damage due to oxidation or organic fouling. Activated carbon is a favored water treatment technique because of its multifunctional nature and the fact that it adds nothing detrimental to the treated water.
Most activated carbon is made from raw materials such as coconut and coal. Typical surface area for activated carbon is approx. 1,000 square meters per gram. However, different raw materials produce different types of activated carbon varying in hardness, density, pore and particle sizes, surface areas, extractables, ash, and pH. These differences in properties make certain carbons preferable over others in different applications.
The two principle mechanisms by which activated carbon removes contaminants from water are absorption and catalytic reduction. Organics are removed by adsorption and residual disinfectants are removed by catalytic reduction.
Total Dissolved Solids (TDS) is a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular (colloidalsol) suspended form. Generally the operational definition is that the solids must be small enough to survive filtration through a filter with two-micrometer (nominal size or smaller) pores. TDS are normally discussed only for fresh water systems, as salinity includes some of the ions constituting the definition of TDS. The principle application of TDS is the study of water quality for streams, rivers, lakes, although TDS is not generally considered a primary pollutant it is used as an indication of aesthetic characteristics of drinking water and as an aggregate indicator of the presence of a broad array of chemical contaminants.
Primary sources for TDS in receiving waters are agricultural and residential runoff, clay rich mountain waters, leaching of soil contamination and point source water pollution discharge from industrial or sewage treatment plants. The most common chemical constituents are calcium, phosphates, nitrates, sodium, potassium, and Chloride, which are found in nutrient runoff, general storm Water runoff and runoff from snowy climates where road de-icing salts are applied. The chemicals may be cations, anions, molecules or agglomerations on the order of one thousand or fewer molecules,so long as a soluble micro-granule is formed. More exotic and harmful elements of TDS are pesticides arising from surface runoff. Certain naturally occurring TDS arise from the weathering and dissolution of rocks and soils. The USA has established a secondary water quality standard of 500 – 1000 mg/l to provide a palatability of drinking water.
TDS are differentiated from total suspended solids (TSS) in that the latter cannot pass through a sieve of two micrometers and yet are indefinitely suspended in solution. The term “settleable solids” refers to material of any size that will not remain suspended or dissolved in a holding tank not subject to to motion, and excludes both TDS and TSS. Settleable solids may include larger particulate matter or insoluble molecules.
Natural sources of iron and manganese are more common in deeper wells where the water has been in contact with rock for a longer period of time. In coal mining regions of the state, these metals may also occur from both deep and surface mining activities. Iron and manganese often occur together in groundwater but manganese usually occurs in much lower concentrations than iron.
Both iron and manganese are readily apparent in drinking water supplies. Both impart a strong metallic taste to the water and both cause staining. Water coming from wells and springs with high iron and/or manganese may appear colorless initially but orange-brown (iron) or black (manganese) stains or particals quickly appear as the water is exposed to oxygen.
Ultraviolet water purification (UV) lamps produce UV-C or germicidal UV, radiation of much greater intensity than sunlight. Almost all of a UV lamps output is concentrated in the 254 nanometers (nm) region in order to take full advantage of the germicidal properties of this wavelength. Most UV systems are combined with various forms of filtration, as UV light is only capable of killing microorganisms such as bacteria, viruses, molds, algae, yeast, oocysts like cryptosporidium and giardia.
UV light generally has no impact on chlorine, VOCs, heavy metals, and other chemical contaminants. Nevertheless, it is probably the most cost effective and efficient technology available to eliminate a wide range of biological contaminants from the water supply. Recent testing has also shown that UV can be effective at destroying certain VOCs, although we would not specifically recommend the technology for VOC reduction.
UV water treatment offers many advantages over other forms of water treatment for microbiological contaminants. Most importantly, it does not introduce any chemicals to the water, it produces no bi-products, and it does not alter the taste, pH, or other properties of the water. Accordingly, in addition to produce safe drinking water, it is not harmful to piping systems.
Reverse Osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove ions, molecules, and larger particles from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property, that is driven by chemical potential differences in the solvent, a thermodynamic parameter. Reverse Osmosis can remove many types of dissolved and suspended species from water, including bacteria, and is used in both industrial processes and the production of potable water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be selective, this membrane should not allow large molecules or ions through the pores, but should allow smaller components of the solution to pass freely.
The normal osmosis process, the solvent naturally moves from an area of low solute concentration, through a membrane, to an area of high solute concentration. The driving force for the movement of the solvent is the reduction in the free energy of the system when the difference in solvent concentration on either side of the membrane is reduced, generating osmotic pressure due to the solvent moving into the more concentrated solution. Applying an external pressure to reverse the natural flow of pure solvent, thus, in reverse osmosis. The process is similar to other membrane technology applications. However, key differences are found between reverse osmosis and filtration. The predominant removal mechanism in membrane filtration is straining, or size exclusion, so the process can theoretically achieve perfect efficiency regardless of parameters such as the solutions pressure and concentration. RO also involves diffusion, making the process dependent on pressure, flow rate, and other conditions. RO is also known for its use in drinking water purification from sea water, removing the salt and other effluent materials from the water molecules.
PH is a measure of hydrogen ion concentration; a measure of acidity or alkalinity of a solution. The pH scale usually ranges from 0-14. Aqueous solutions at 25C with a pH less than seven are acidic, while those with a pH greater than seven are basic or alkaline. A pH level of 7.0 at 25C I’ds defines as ‘Neutral’. Very strong acids may have a negative pH, while very strong bases may have a pH greater than 14.
Examples of pH values of common chemicals
we work with many acids (low pH0 and bases (high pH) every day. Examples of pH values of lab chemicals and household products include:
0 – hydrochloride acid
2.0 – lemon juice
2.2 – vinegar
4.0 – wine
7.0 – pure water (Neutral)
7.4 – human blood
13.0 – lye
14.0 sodium hydroxide
Not all liquids have a pH value, pH only has meaning in an aqueous solution (in water). Meny chemicals, including liquids, do not have pH values. If there’s no water there’s no pH! For example, there is no pH value for vegetable oil, gasoline, or pure alcohol. pH is used in everyday life as well as science and industry. It is used in cooking, to design cocktails, in cleaners, and in food preservation.
Let’s talk about how critical proper pre treatment is for any reverse osmosis system large or small and whether the raw water source is municipal or a private well. As we discussed in earlier blogs there are several materials or contaminants in the water that can foul the taste of your brew and it is some of the same things that can foul your RO system.
Before any water treatment equipment is sized and designed you should consult your latest water quality report. If you are on a municipal water supply you can simply Google the current water analysis from your local water company and find out exactly what is in your water. If you are on a private well water supply you should have the water supply tested by a local reputable lab. We here at http://www.microbrewwwatersystems.com will read and consult you on any report at no charge.
the most common fouling and scaling materials to RO are turbidity, iron, manganese, calcium, magnesium, organics, chlorine, and Chloramines. You can find all of these pesky things in most water supplies some higher and some lower. If you have have high turbidity which is generally found in in untreated well water you will require a http://www.microbrewwatersystems.com NXT sand Filter. Common levels of iron and manganese can be treated with a http://www.microbrewwatersystems.com BrewSoft system. The most common is water hardness resulting from calcium and magnesium and trust me you have it….a good antiscalent system or BrewSoft will eliminate if not slow down those problems. And for some of the worst enemies, chlorine and CHLORAMINES. Remember that we talked about standard granulated carbon and how it will not work with chlorimines but will work with chlorine and organics. This will require our http://www.microbrewwatersystems.com special carbon blend that takes care of all of those issues.
Sizing is also very critical in all pre treatment systems for proper flow rates, contact times, flow, and pressure.
Please Brewers ….do your homework when it comes to the proper pre treatment design for your RO investment…if not it will come back to bite you in a very expensive way.
Of course we here at http://www.microbrewwatersystems.com can do your home work for you..
see ya next time
Most municipal water supplies are treated with chlorine and now more than ever Chloramine which becomes a big problem for brewing bringing bad things to the flavor of your beer.
Chlorine has been used for more than 100 years for disinfection of drinking water to protect public health from diseases which are caused by bacteria, viruses, and others orgnisms. Chlorine was fairly easy to remove within the brewing process you could simply boil it off, let the water stand for a few hours, or use a basic carbon filter.
Now more than ever Chloramine is being added to our municipal water supplies and its primary purpose is to maintain disinfection for a much longer period of time in the distribution system. This is a completely different problem that is not so easy to deal with. Chloramines are produced by combining chlorine and ammonia. While highly toxic at high levels, neither pose health concerns to us at the level used for drinking water but do cause problems for Brewers large and small.
one of the problems is that yeast eat Chloramine and chlorine and produce ‘chlorophenols’. These phenols have extremely low taste thresholds; you can taste them even if they exist in only a few parts per billion. Your beer will have a difficult time on defining it’s true flavor and will have an almost chemical or medicinal after taste.
The best way of treating both of these problems is by using a high quality Catalytic Activated Carbon System such as our http://www.microbrewwater.com SC System. Standard GAC or activated carbon will not remove chloramines. Our product has a high capacity and a high flow rate design to maximize its efficiency and give you the flavor you want without the after tastes and brewing problems.
Next time we will discuss the many benefits of using REVERSE OSMOSIS…