This listing of chemicals used in the treatment of drinking water classifies them according to th... more This listing of chemicals used in the treatment of drinking water classifies them according to their purpose in water treatment. We have also listed any special properties of the chemicals and safe handling procedures of the hazardous chemicals. D. Appendix-Common Chemicals used in Public Water System Treatment: i. pH/Alkalinity Adjustments: A discussion of the chemicals used in pH and alkalinity adjustments exists not just because there is a desired level of pH and alkalinity in finished water, but because the pH levels and alkalinity levels of water throughout the treatment process affects the dosing and effectiveness of other chemicals involved in the water treatment process. For example, in the coagulation/flocculation basins the alkalinity in the water will be consumed by the formation of flocs. This means that an adequate amount of bicarbonate must be present to offset the loss of alkalinity to floc formation. There are several chemicals that can be added to offset the loss of alkalinity or to make adjustments to the pH during the water treatment process. Six chemicals that are commonly used in West Virginia plants include: 1. Sodium carbonate (Na 2 CO 3): Sodium carbonate or soda ash is a very common chemical used to raise the pH levels of the water from a more acidic level into the neutral range. It is also known as a water softener. Mildly alkaline, it is produced from inexpensive and plentiful raw materials. Soda ash is a white, odorless powder with a slightly alkaline taste. The handler should follow standard safety precautions to minimize health hazards. A ventilation system is recommended to control the dust and keep operator exposure as low as possible. The dust of this compound can irritate the mucous membranes and potentially cause sores in the nasal passage. Protective gear like safety goggles and dust respirators should be worn during handling. Additionally, exposed skin surfaces should be protected with a cream or petroleum jelly. The storage containers must be designed to protect the chemical from heat and moisture. 2. Lime (Ca(OH) 2 and/or CaO): Lime is the generic term used to describe hydrated lime and quicklime. Calcium hydroxide (hydrated lime) and calcium oxide (quicklime) are chemicals frequently used to raise the pH of raw water before the water is treated with alum or ferric sulfates for coagulation/flocculation. Hydrated lime and quicklime are colorless crystals or white powders that are available for purchase in bags, bulk or by truckload. Care in handling of both forms should be taken since the dust can be quite irritating to the skin and eyes. Hydrated lime is commonly used by small facilities because it can be directly applied to the water treatment process. Quicklime, (in pellet form), must first be slaked, or mixed with water then heated to turn it into hydrated lime before use. When quicklime is mixed with water there is a potential for explosions due to the heat released from the chemical combinations. Lime also has reactions with alum and ferric sulfates so direct mixing should be avoided. Storage of these products should be in cool, dry places. Always wear goggles, a dust mask and protective clothing when handling lime. A face shield should be worn when inspecting lime slakers due to splattering.
This listing of chemicals used in the treatment of drinking water classifies them according to th... more This listing of chemicals used in the treatment of drinking water classifies them according to their purpose in water treatment. We have also listed any special properties of the chemicals and safe handling procedures of the hazardous chemicals. D. Appendix-Common Chemicals used in Public Water System Treatment: i. pH/Alkalinity Adjustments: A discussion of the chemicals used in pH and alkalinity adjustments exists not just because there is a desired level of pH and alkalinity in finished water, but because the pH levels and alkalinity levels of water throughout the treatment process affects the dosing and effectiveness of other chemicals involved in the water treatment process. For example, in the coagulation/flocculation basins the alkalinity in the water will be consumed by the formation of flocs. This means that an adequate amount of bicarbonate must be present to offset the loss of alkalinity to floc formation. There are several chemicals that can be added to offset the loss of alkalinity or to make adjustments to the pH during the water treatment process. Six chemicals that are commonly used in West Virginia plants include: 1. Sodium carbonate (Na 2 CO 3): Sodium carbonate or soda ash is a very common chemical used to raise the pH levels of the water from a more acidic level into the neutral range. It is also known as a water softener. Mildly alkaline, it is produced from inexpensive and plentiful raw materials. Soda ash is a white, odorless powder with a slightly alkaline taste. The handler should follow standard safety precautions to minimize health hazards. A ventilation system is recommended to control the dust and keep operator exposure as low as possible. The dust of this compound can irritate the mucous membranes and potentially cause sores in the nasal passage. Protective gear like safety goggles and dust respirators should be worn during handling. Additionally, exposed skin surfaces should be protected with a cream or petroleum jelly. The storage containers must be designed to protect the chemical from heat and moisture. 2. Lime (Ca(OH) 2 and/or CaO): Lime is the generic term used to describe hydrated lime and quicklime. Calcium hydroxide (hydrated lime) and calcium oxide (quicklime) are chemicals frequently used to raise the pH of raw water before the water is treated with alum or ferric sulfates for coagulation/flocculation. Hydrated lime and quicklime are colorless crystals or white powders that are available for purchase in bags, bulk or by truckload. Care in handling of both forms should be taken since the dust can be quite irritating to the skin and eyes. Hydrated lime is commonly used by small facilities because it can be directly applied to the water treatment process. Quicklime, (in pellet form), must first be slaked, or mixed with water then heated to turn it into hydrated lime before use. When quicklime is mixed with water there is a potential for explosions due to the heat released from the chemical combinations. Lime also has reactions with alum and ferric sulfates so direct mixing should be avoided. Storage of these products should be in cool, dry places. Always wear goggles, a dust mask and protective clothing when handling lime. A face shield should be worn when inspecting lime slakers due to splattering.
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