Wells

Until recently, the point-of-use water treatment industry focused on improving the aesthetic quality of drinking water. The industry has lately been thrust into the forefront of treatment of contaminated drinking waters that pose a serious health hazard. The response has been a plethora of companies and products promising to render the consumer’s drinking water safe and contaminant free. The individual is left to sift through advertising claims and technical data to select the appropriate treatment method.

Water is often called the universal solvent. As water moves underground or over land, it dissolves a variety of compounds including minerals, salts, and organic compounds. The concentration of “total dissolved solids” (TDS) in a water sample is a measure of the dissolved compounds in the water small enough to pass through a 2-micrometer sieve. For comparison, one human hair is approximately 100 micrometers in diameter. A TDS test measures the amount, but does not identify the individual compounds or their sources.

Sulfate (SO4) is a naturally occurring mineral that can be dissolved into groundwater. Hydrogen sulfide (H2S) is a colorless gas that gives water a distinctive sulfur or “rotten egg” smell and taste, which may be especially noticeable in hot water. The presence of low levels of hydrogen sulfide in household water is not a health hazard, but hydrogen sulfide can make water more corrosive, which can result in leaching of metals present in the plumbing system. The offensive odor and other nuisance problems associated with hydrogen sulfide may make treatment desirable.

Knowing the amount of sodium in your drinking water is important for your health, especially if you have high blood pressure. Sodium is an essential mineral for maintaining a healthy fluid balance and is important for brain function and muscle contractions but consuming too much sodium can elevate your blood pressure.

Sodium and chloride, which together compose common table salt, often occur naturally in groundwater as it dissolves minerals underground. Higher levels of sodium and chloride in household water, however, often come from manmade sources such as road salt, industrial wastes, sewage, fertilizers, or water softeners. In coastal areas, sodium and chloride can also enter groundwater via salt water intrusion into fresh water aquifers. In high enough concentrations, salt water intrusion can render groundwater unsuitable for drinking, cooking, or irrigating.

Iron and manganese are naturally occurring minerals found in certain rocks and soils that can be dissolved by groundwater. Corroding iron or galvanized steel pipes may also be a source of iron in household water. Typically, neither iron nor manganese presents a health risk to humans when present in a household water supply; however, a portion of the population suffering from hemochromatosis (excess iron in the body) may be especially sensitive to iron in drinking water. Iron and manganese are primarily associated with nuisance problems such as staining of clothes and plumbing fixtures or objectionable taste. Iron and manganese are similar chemically and therefore produce similar problems. Iron and manganese are usually either dissolved (in solution) in water or found in particulate form.

Concerns about personal and family health may lead you to question the safety of the water used in your household. Perhaps you have been alarmed by recent publicity about water pollution problems and their effect on water used in the home for drinking, cooking, and many other purposes. You may be particularly uncertain about the quality of your household water if you rely on your own well or other private water supply. With the availability of modern water treatment equipment and the aggressive marketing of these devices, you may wonder about the need to install such equipment in your home.

Reclaimed water is wastewater from a municipal sewage treatment facility that has been treated to be suitable for beneficial use. Reclaimed water is categorized into four water quality Classes (I-IV) which govern their potential uses based on the level of treatment (or quality) attained. These guidelines apply only to use of Class IV reclaimed water generated from a centralized wastewater treatment works. Guidance on the use of Class I, II and III reclaimed water can be found in the Department’s Guidelines for Land Application/Reuse of Treated Municipal Wastewaters (MDE-WMA-001-04/10).

Greywater is any household wastewater other than that used for toilet flushing. This water could be reused around the home (for purposes other than drinking water). An example of greywater use is landscape irrigation. Wastewater that comes in contact with human waste is referred to as blackwater. However, the definition of greywater varies according to state regulations. In many states greywater is defined as household wastewater from baths, showers, laundry washing, and lavatory sinks. However, greywater does not include wastewater from kitchen sinks, dishwashers, and toilets. Kitchen sink and dishwasher wastewater is often classified as blackwater because it may contain higher levels of organic materials (such as food waste) compared to greywater sources. The high organic content of these blackwater sources can lead to low oxygen content and greater microbial activity, and thus may require more stringent treatment. Additionally, if laundry water is used for diaper washing it is usually classified as blackwater rather than greywater since it has come in contact with human waste.

Artículo preparado originalmente para el boletín de Headwaters (Número 1, Volumen 8).