greg-cws
04-23-2009, 08:58 PM
Chlorine, a cheap and efficient killer
The water that we drink is stored, treated and distributed to our homes by public and private water utilities. Algae, bacteria, fungi and viruses can often be found in untreated water. Americans have grown to expect a safe drinking water supply, but achieving that safety is not a simple task.
Unsafe Water
One hundred and fifty years ago, much of the USA's water supply was teeming with various forms of aquatic organisms. Waterborne diseases, such as cholera, typhoid, and dysentery, were a serious health problem, and they are still major concerns in third-world nations where over a billion people lack clean drinking water and almost two billion lack sewage systems. In 1992, the World Bank rated drinking water as first on its list of preventable environmental hazards worldwide. Since 1991 the largest cholera epidemic in recent history has infected over 800,000 people from Peru to Mexico.
Waterborne microorganisms include coliform and heterotrophic bacteria, viruses, and protozoa. These organisms range in size from extremely small viruses to relatively large protozoan cysts. They also vary greatly in the nature of their surface, living, and replication characteristics. These pathogenic icroorganisms occur naturally in lakes, streams, reservoirs, and most surface water sources. Groundwater supplies are now becoming a subject of increasing concern, because enteric viruses and other organisms can leach into the groundwater system from the land application or burial of sewage sludge and ther treatment wastes.
Since water utilities first began using filtration and disinfection systems a century ago, the risk of disease from drinking water in first-world countries has been greatly reduced. Despite the significant progress that has been made, there are still numerous disease cases resulting from contaminated drinking water in the United States. Health risks from aquatic pathogens range from mild gastrointestinal distress to systemic disease and, in severe cases, death. Americans consume over three and a half billion gallons of treated water daily. There are nearly 250,000 public water supply systems in the United States, serving everything from the smallest towns to major metropolitan centers. Ninety percent of the population receives its water through these community water systems, with the rest using private wells or other individual sources. The United States Environmental Protection Agency (EPA) ranks drinking water pollution as one of the top four environmental threats to health
From 1971 to 1988, there were nearly 137,000 cases of waterborne disease--or an average of 7,600 cases per year--reported in this country. It is suspected that there were numerous undocumented cases as well, because many cases of gastrointestinal illness are not recognized as part of a pattern of waterborne disease. It has been estimated that only half of waterborne disease outbreaks in community water systems and about one third of those in non community systems are detected, investigated, and reported. Microbes in tap water may be responsible for as much as one in three cases of gastrointestinal illness in the United States. Rates of waterborne illness as high as 900,000 cases and 900
deaths per year have been estimated by the Natural Resources Defense Council (Lee 1993).
A Cheap and Efficient Killer
The first health standard for drinking water was established in 1914 by the U.S. Public Health Service to protect against acute bacterial diseases. Standards have since been added to include water source protection as well as regulation of radioactivity and a host of other organic and inorganic chemicals, radionuclides, and microorganisms. In the nineteenth century, progressive American communities began to separate drinking water delivered to users from reservoirs and wells, from household and industrial wastes discharged by users into sewage water systems. Many people in developing countries still do not have separate drinking water and sewer systems. Water utilities in the USA began treating drinking water with chlorine in 1908.
Chlorine and it's compounds and by-products are currently used by over 98 percent of all U.S. water utilities that disinfect drinking water. It is a cheap and efficient killer. By adding chlorine and it's compounds and by-products to drinking water, almost all organisms living in the water are killed. Chlorine and it's by-products remain in the water as it is distributed to homes and businesses, thereby retaining it's ability to kill organisms that they come in contact with.
Although chlorine's disinfectant value has been known for nearly a century, the mechanism by which the compound kills or inactivates microorganisms is not clearly understood.
The Process
The water treatment process involves a series of different steps. Some of the major steps include flocculation and coagulation (the joining of small particles of matter in the water into larger ones that can more readily be removed), sedimentation (the settling of suspended particles in the water to the bottom of basins from which they can be removed), and filtration (the filtering or straining of the water through various types of materials to remove much of the remaining suspended particles), as well as chemical disinfection.
Chlorination is usually performed at several stages of the treatment process. Prechlorination may be performed in the initial stages to combat the algae and other aquatic life that may interfere with treatment equipment and other stages in the process. The major chlorination stage, however, occurs as the final treatment step after the completion of the other major cleaning processes, where the concentration and residual content of the chlorine can be closely monitored. In this post chlorination phase, the chemical is more effective in the filtered water, and less contact time is required for the chemical to disinfect the water supply. Chlorination can deactivate microorganisms by a variety of mechanisms, such as damage to cell membranes, inhibition of specific enzymes, destruction of nucleic acids, and other lethal effects to vital functions . The effectiveness of the chlorination process depends upon a variety of factors, however, including chlorine concentration and contact time, water temperature, pH value, and level of turbidity.
Disinfectant concentrations and contact times vary widely, usually depending on the characteristics of the water being treated.
Chlorination is the cheapest, most effective way to disinfect water that is stored, processed and distributed to our homes. It is a cheap, efficient killer that helps protect us from deadly microbial diseases.
Chlorine and its by-products must be removed from your water before you or your family bathe, shower in it, or drink it.
The Smart Bottle Home Empowered Water System is specially designed to address water hardness, heavy metals, pesticides, herbicides, chlorine, chloramine, tastes, and odors. (http://www.smartbottlesystem.com)
The water that we drink is stored, treated and distributed to our homes by public and private water utilities. Algae, bacteria, fungi and viruses can often be found in untreated water. Americans have grown to expect a safe drinking water supply, but achieving that safety is not a simple task.
Unsafe Water
One hundred and fifty years ago, much of the USA's water supply was teeming with various forms of aquatic organisms. Waterborne diseases, such as cholera, typhoid, and dysentery, were a serious health problem, and they are still major concerns in third-world nations where over a billion people lack clean drinking water and almost two billion lack sewage systems. In 1992, the World Bank rated drinking water as first on its list of preventable environmental hazards worldwide. Since 1991 the largest cholera epidemic in recent history has infected over 800,000 people from Peru to Mexico.
Waterborne microorganisms include coliform and heterotrophic bacteria, viruses, and protozoa. These organisms range in size from extremely small viruses to relatively large protozoan cysts. They also vary greatly in the nature of their surface, living, and replication characteristics. These pathogenic icroorganisms occur naturally in lakes, streams, reservoirs, and most surface water sources. Groundwater supplies are now becoming a subject of increasing concern, because enteric viruses and other organisms can leach into the groundwater system from the land application or burial of sewage sludge and ther treatment wastes.
Since water utilities first began using filtration and disinfection systems a century ago, the risk of disease from drinking water in first-world countries has been greatly reduced. Despite the significant progress that has been made, there are still numerous disease cases resulting from contaminated drinking water in the United States. Health risks from aquatic pathogens range from mild gastrointestinal distress to systemic disease and, in severe cases, death. Americans consume over three and a half billion gallons of treated water daily. There are nearly 250,000 public water supply systems in the United States, serving everything from the smallest towns to major metropolitan centers. Ninety percent of the population receives its water through these community water systems, with the rest using private wells or other individual sources. The United States Environmental Protection Agency (EPA) ranks drinking water pollution as one of the top four environmental threats to health
From 1971 to 1988, there were nearly 137,000 cases of waterborne disease--or an average of 7,600 cases per year--reported in this country. It is suspected that there were numerous undocumented cases as well, because many cases of gastrointestinal illness are not recognized as part of a pattern of waterborne disease. It has been estimated that only half of waterborne disease outbreaks in community water systems and about one third of those in non community systems are detected, investigated, and reported. Microbes in tap water may be responsible for as much as one in three cases of gastrointestinal illness in the United States. Rates of waterborne illness as high as 900,000 cases and 900
deaths per year have been estimated by the Natural Resources Defense Council (Lee 1993).
A Cheap and Efficient Killer
The first health standard for drinking water was established in 1914 by the U.S. Public Health Service to protect against acute bacterial diseases. Standards have since been added to include water source protection as well as regulation of radioactivity and a host of other organic and inorganic chemicals, radionuclides, and microorganisms. In the nineteenth century, progressive American communities began to separate drinking water delivered to users from reservoirs and wells, from household and industrial wastes discharged by users into sewage water systems. Many people in developing countries still do not have separate drinking water and sewer systems. Water utilities in the USA began treating drinking water with chlorine in 1908.
Chlorine and it's compounds and by-products are currently used by over 98 percent of all U.S. water utilities that disinfect drinking water. It is a cheap and efficient killer. By adding chlorine and it's compounds and by-products to drinking water, almost all organisms living in the water are killed. Chlorine and it's by-products remain in the water as it is distributed to homes and businesses, thereby retaining it's ability to kill organisms that they come in contact with.
Although chlorine's disinfectant value has been known for nearly a century, the mechanism by which the compound kills or inactivates microorganisms is not clearly understood.
The Process
The water treatment process involves a series of different steps. Some of the major steps include flocculation and coagulation (the joining of small particles of matter in the water into larger ones that can more readily be removed), sedimentation (the settling of suspended particles in the water to the bottom of basins from which they can be removed), and filtration (the filtering or straining of the water through various types of materials to remove much of the remaining suspended particles), as well as chemical disinfection.
Chlorination is usually performed at several stages of the treatment process. Prechlorination may be performed in the initial stages to combat the algae and other aquatic life that may interfere with treatment equipment and other stages in the process. The major chlorination stage, however, occurs as the final treatment step after the completion of the other major cleaning processes, where the concentration and residual content of the chlorine can be closely monitored. In this post chlorination phase, the chemical is more effective in the filtered water, and less contact time is required for the chemical to disinfect the water supply. Chlorination can deactivate microorganisms by a variety of mechanisms, such as damage to cell membranes, inhibition of specific enzymes, destruction of nucleic acids, and other lethal effects to vital functions . The effectiveness of the chlorination process depends upon a variety of factors, however, including chlorine concentration and contact time, water temperature, pH value, and level of turbidity.
Disinfectant concentrations and contact times vary widely, usually depending on the characteristics of the water being treated.
Chlorination is the cheapest, most effective way to disinfect water that is stored, processed and distributed to our homes. It is a cheap, efficient killer that helps protect us from deadly microbial diseases.
Chlorine and its by-products must be removed from your water before you or your family bathe, shower in it, or drink it.
The Smart Bottle Home Empowered Water System is specially designed to address water hardness, heavy metals, pesticides, herbicides, chlorine, chloramine, tastes, and odors. (http://www.smartbottlesystem.com)