INTRODUCTION
The volume of industrial and domestic waste water is increasing significantly year by year with the change in the lifestyle based on mass consumption and mass disposal brought about by the dramatic development of economies and industries. Therefore, effective advanced wastewater treatment is required because wastewater contains a variety of constituents such as particles, organic materials, and emulsion depending on the resource. However, residual chemicals that remain during the treatment of wastewaters form a variety of known and unknown by-products through reactions between the chemicals and some pollutants. Chronic exposure to these by-products or residual chemicals through the ingestion of drinking water, inhalation and dermal contact during regular indoor activities (e.g., showering, bathing, cooking) may pose cancer and non-cancer risks to human health. For example, residual aluminium salts in treated water may cause Alzheimer's disease (AD). As for carbon nanotubes (CNTs), despite their potential impacts on human health and the environment having been receiving more and more attention in the recent past, existing information on the toxicity of CNTs in drinking water is limited with many open questions. Furthermore, though general topics on the human health impacts of traditional water treatment chemicals have been studied, no comparative analysis has been done. Therefore, a qualitative comparison of the human health effects of both residual CNTs and traditional water treatment chemicals is given in this paper. In addition, it is also important to cover and compare the human health effects of CNTs to those of traditional water treatment chemicals together in one review because they are both used for water treatment and purification.
Overview
The water delivered to your house is purified to ensure it is safe to drink. Water treatment plants use a variety of chemicals to remove contaminates that affect the taste, odor, cloudiness and overall safety of water. Waste-water treatment plants similarly treat used water before releasing it into the environment. The effectiveness of these chemicals is balanced with the potential health effects.
Significance
Industrial water treatment chemicals kill bacteria and viruses in the water supply. This prevents gastrointestinal illness that causes diarrhea, vomiting and cramps. Water treatment chemicals are also used to induce coagulation of particles. This reduces the cloudiness of water. Chemicals such as polyphosphate are used in waste-water treatment to remove iron and magnesium. This maintains a clear water color by eliminating mineral staining.
Treatments
Several chemicals are used to treat drinking water in order to meet safety guidelines. Chloramines, chlorine and chlorine dioxide are used as disinfectants for drinking water. Aluminium sulfate, polyaluminum chloride or ferric sulfates are used as coagulants in drinking water. In addition, coagulant aids containing residual acrylamide or epichlorohydrin monomers may be used to reduce turbidity and organic buildup. Sodium hydroxide may be added to control the pH of water and fluoride may be added as a nutritional supplement in drinking water.
Effectiveness
Water treatment chemicals are highly effective. A heterotrophic plate count measures the amount of bacteria present in the water supply. It indicates how well the chemical disinfectants are handling bacterial contamination. Another method used to determine the effectiveness of disinfection is to measure the residual chlorine in the water supply. A concentration of 4mg/L is ideal. If the concentration is higher, it means less bacteria is present. If the concentration is lower, it means more bacteria is present. The amount of chlorine added is modified to compensate.
Safety
Chemicals used to treat water may also have side effects. In the process of disinfection, byproducts are formed. Bromate, chlorite, haloacetic acids and trihalomethanes are byproducts of water disinfection. These chemicals are linked to an increased risk of cancer, anemia, liver problems, kidney problems and effects on the nervous system. According to the EPA, this risk exists for people who drink water with chemical levels in excess of the EPA's standard.
The volume of industrial and domestic waste water is increasing significantly year by year with the change in the lifestyle based on mass consumption and mass disposal brought about by the dramatic development of economies and industries. Therefore, effective advanced wastewater treatment is required because wastewater contains a variety of constituents such as particles, organic materials, and emulsion depending on the resource. However, residual chemicals that remain during the treatment of wastewaters form a variety of known and unknown by-products through reactions between the chemicals and some pollutants. Chronic exposure to these by-products or residual chemicals through the ingestion of drinking water, inhalation and dermal contact during regular indoor activities (e.g., showering, bathing, cooking) may pose cancer and non-cancer risks to human health. For example, residual aluminium salts in treated water may cause Alzheimer's disease (AD). As for carbon nanotubes (CNTs), despite their potential impacts on human health and the environment having been receiving more and more attention in the recent past, existing information on the toxicity of CNTs in drinking water is limited with many open questions. Furthermore, though general topics on the human health impacts of traditional water treatment chemicals have been studied, no comparative analysis has been done. Therefore, a qualitative comparison of the human health effects of both residual CNTs and traditional water treatment chemicals is given in this paper. In addition, it is also important to cover and compare the human health effects of CNTs to those of traditional water treatment chemicals together in one review because they are both used for water treatment and purification.
Overview
The water delivered to your house is purified to ensure it is safe to drink. Water treatment plants use a variety of chemicals to remove contaminates that affect the taste, odor, cloudiness and overall safety of water. Waste-water treatment plants similarly treat used water before releasing it into the environment. The effectiveness of these chemicals is balanced with the potential health effects.
Significance
Industrial water treatment chemicals kill bacteria and viruses in the water supply. This prevents gastrointestinal illness that causes diarrhea, vomiting and cramps. Water treatment chemicals are also used to induce coagulation of particles. This reduces the cloudiness of water. Chemicals such as polyphosphate are used in waste-water treatment to remove iron and magnesium. This maintains a clear water color by eliminating mineral staining.
Treatments
Several chemicals are used to treat drinking water in order to meet safety guidelines. Chloramines, chlorine and chlorine dioxide are used as disinfectants for drinking water. Aluminium sulfate, polyaluminum chloride or ferric sulfates are used as coagulants in drinking water. In addition, coagulant aids containing residual acrylamide or epichlorohydrin monomers may be used to reduce turbidity and organic buildup. Sodium hydroxide may be added to control the pH of water and fluoride may be added as a nutritional supplement in drinking water.
Effectiveness
Water treatment chemicals are highly effective. A heterotrophic plate count measures the amount of bacteria present in the water supply. It indicates how well the chemical disinfectants are handling bacterial contamination. Another method used to determine the effectiveness of disinfection is to measure the residual chlorine in the water supply. A concentration of 4mg/L is ideal. If the concentration is higher, it means less bacteria is present. If the concentration is lower, it means more bacteria is present. The amount of chlorine added is modified to compensate.
Safety
Chemicals used to treat water may also have side effects. In the process of disinfection, byproducts are formed. Bromate, chlorite, haloacetic acids and trihalomethanes are byproducts of water disinfection. These chemicals are linked to an increased risk of cancer, anemia, liver problems, kidney problems and effects on the nervous system. According to the EPA, this risk exists for people who drink water with chemical levels in excess of the EPA's standard.