What really happened to our tap water and underground water?

Clean water is one of the most important needs of our bodies. It is a sad fact that something as essential to life as clean drinking water can no longer be granted to us. Unsafe water is not just a third world problem. In fact, safe drinking water is even harder to find especially in industrially developed countries such as the U.S.

According to research articles and news, most tap and well water in the U.S. now are not safe for drinking due to heavy industrial and environmental pollution. We have reached a point that all sources of our drinking water, including municipal water systems, wells, lakes, rivers, and even glaciers, contain some level of contamination. Contaminants range from naturally-occurring minerals to man-made chemicals and by-products. While many contaminants are found at levels not enough to cause immediate discomfort or sickness, it is proven that even low-level exposure to many common contaminants will, over time, cause severe illnesses including liver damage, cancer, and other serious ailments. Even the chemicals commonly used to treat municipal water supplies such as chlorine and fluoride are toxic and are known to have significant adverse effects on the human body.

2. Groundwater: The water emerging from some deep ground sources may have fallen as rain many decades, hundreds, thousands or in some cases millions of years ago. Soil and rock layers naturally filter the ground water to a high degree of clarity before it is pumped to the treatment plant. Such water may emerge as springs, artesian springs, or may be extracted from boreholes or wells. Deep ground water is generally of very high bacteriological quality (i.e., pathogenic bacteria or the pathogenic protozoa are typically absent), but the water is typically rich in dissolved solids, especially carbonates and sulfates of calcium and magnesium. Depending on the strata through which the water has flowed, other ions may also be present including chloride, and bicarbonate. There may be a requirement to reduce the iron or manganese content of this water to make it pleasant for drinking, cooking, and laundry use. Disinfection may also be required.

3. Hardness of natural waters is caused largely by calcium and magnesium salts and to a small extent by iron, aluminum, and other metals. Hardness resulting from the bicarbonates and carbonates of calcium and magnesium is called temporary hardness and can be removed by boiling, which also sterilizes the water. The residual hardness is known as noncarbonate, or permanent, hardness. The methods of softening noncarbonate hardness include the addition of sodium carbonate and lime and filtration through natural or artificial zeolites which absorb the hardness-producing metallic ions and release sodium ions to the water. Sequestering agents in detergents serve to inactivate the substances that make water hard.

4. Treatment. If the water in a consumer's home has the problems with turbidity, taste, odor, or color, what can be done? Fortunately, there are several products available that can be directly installed in the home to treat these problems. Point-of-Use (POU) and Point-of-Entry (POE) technologies can treat water in the home and reduce these problems. A process that is effective in reducing most of these aesthetic problems is the use of an activated carbon filter. These filters are specially designed for the removal of solid particles from the water. Activated carbon is a unique material known for its ability to adsorb (bind to its surface) soluble organic compounds and certain gases. This quality makes it specially suited for use in water treatment and allows it to act as a fine screen which traps solid particles, but allows the water to pass through. Activated carbon filters are available in three forms: solid block, precoat, and granular. Carbon filters may either attach directly to the faucet, or may be installed under the sink; filters for the whole house may also be used to treat staining and odor problems. Most taste and odor problems can be reduced with the use of an activated carbon filter. To combat the taste and odor problem of excess amounts of chlorine, for example, many consumers install a filter at the kitchen tap. The filter adsorbs the excess chlorine, and produces tasty, clean water for cooking and drinking.

Turbidity may also be removed with an activated carbon filter, or a particulate filter. The particulate filter will trap the fine particles that cause a cloudy appearance, and its use will result in a clear, clean appearance.

5. The problem of hydrogen sulfide in water is more complex than many other odor problems. If the concentration of hydrogen sulfide is very low, then an activated carbon filter may be used. For greater concentrations, an iron removal filter should be effective in correcting the problem. For high concentrations of hydrogen sulfide, a chlorination system with activated carbon filtration would likely be the best solution. Chlorine is potentially harmful, and must be handled carefully.

6. Treatment techniques. A treatment technique commonly used in the home is a process called reverse osmosis (RO). In this process, the water to be treated is forced against a semi-permeable membrane, which rejects contaminants suspended in the water. The membrane permits the new water to pass to a holding tank where it is then available for use. RO is effective in treating water that has a metallic taste, as well as reducing numerous other health contaminants. It is also often paired with an activated carbon filter.

Distillation is also often used for water treatment. A distillation system raises the water temperature to boiling. The water turns to vapor, leaving behind contaminants that have been dissolved in it, as well as microscopic solids, microorganisms, and organic materials. The clean water vapor enters a condenser where it is cooled, and returned to its liquid state. This process produces clean, clear water with a distinctive clarity.

To treat water that is colored as a result of humic acids, an anion exchange resin may be used. The resin adsorbs the organic bodies that cause the discoloration, and will leave behind clear water. For color problems that are due to low or moderate levels of dissolved iron, a household water softener may remove the impurity. The soluble iron is removed from the water by ion exchange, in the same way that hardness is removed by a water softener. If much of the iron is already precipitated, or the iron concentration is too high for a water softener, an iron removal filter should be used.

7. Whether a water problem involves turbidity, taste, odor, or color, the first step to its treatment is to have the water tested. Testing determines the precise cause of the problem so the ideal treatment may be applied.

When the safety of the water is in question, it should be tested by a state certified, EPA certified, or other reputable laboratory. Testing for turbidity, taste, odor, or color problems may be performed in the home by a professional water treatment dealer. Before purchasing a product, become an educated consumer. Determine what water problems the proposed product reduces, and to what level. Check the product's performance capabilities, maintenance provisions, and warranty. Aesthetic water problems have some easy solutions.

8. The United States has made tremendous advances in the past 25 years to clean up the aquatic environment by controlling pollution from industries and sewage treatment plants. Unfortunately, we did not do enough to control pollution from diffuse, or nonpoint, sources. Today, nonpoint source (NPS) pollution remains the Nation's largest source of water quality problems. It's the main reason that approximately 40 percent of our surveyed rivers, lakes, and estuaries are not clean enough to meet basic uses such as fishing or swimming.

NPS pollution occurs when rainfall, snowmelt, or irrigation runs over land or through the ground, picks up pollutants, and deposits them into rivers, lakes, and coastal waters or introduces them into ground water. Imagine the path taken by a drop of rain from the time it hits the ground to when it reaches a river, ground water, or the ocean. Any pollutant it picks up on its journey can become part of the NPS problem. NPS pollution also includes adverse changes to the vegetation, and flow of streams and other aquatic systems.

NPS pollution is widespread because it can occur any time activities disturb the land or water. Agriculture, forestry, septic systems, recreational boating, urban runoff, construction, physical changes to stream channels, and habitat degradation are potential sources of NPS pollution. Careless or uninformed household management also contributes to NPS pollution problems.

The most common NPS pollutants are sediment and nutrients. These wash into water bodies from agricultural land, small and medium-sized animal feeding operations, construction sites, and other areas of disturbance. Other common NPS pollutants include pesticides, pathogens (bacteria and viruses), salts, oil, grease, toxic chemicals, and heavy metals. Beach closures, destroyed habitat, unsafe drinking water, fish kills, and many other severe environmental and human health problems result from NPS pollutants. Each year the United States spends millions of dollars to restore and protect the areas damaged by NPS pollutants.

Дата добавления: 2015-07-14