Water Treatment Chemicals

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Chemicals serve many purposes in the water treatment process. They remove undesirable substances from water, kill harmful bacteria, help prevent cavities, and help prevent the corrosion of water pipes.

Some water treatment chemicals used in Greensboro:

Sodium Permanganate

Sodium permanganate (NAMNO4) is an oxidizing agent normally added to the water coming into the plant from  Lake Brandt. It helps remove iron, manganese, and objectionable tastes and odors. When iron and manganese are oxidized, they become insoluble in water and can then be removed by sedimentation and filtration processes. 

Sodium permanganate is also used to oxidize the organic contaminants that cause taste and odor problems.

Ferric Sulfate

This is an iron-based coagulant which does very well in removing natural organics from raw water. Ferric Sulfate is a versatile coagulant that can maintain its effectiveness through a broad pH range.

Lime/Caustic

These are alkaline compounds and added to the water for pH and alkalinity adjustment.

Chlorine (Sodium Hypochlorite)

Hypochlorite is added to disinfect water. It work as chlorine for primary disinfectant inside the plant and work as mono-chloramines which is produced when mixed with Ammonia for secondary disinfectant throughout the distribution system.

Orthophosphate

This is a blend of Ortho-Poly Phosphate. It prevents corrosion inside the water pipes.

Fluoride

Fluoridation is used to maintain fluoride concentration in drinking water at levels known to reduce tooth decay for children. At optimum levels, fluoride can reduce the incidence of tooth decay among children by 65%. The amount of fluoride added is regulated by the Environmental Protection Agency (EPA) and North Carolina Department of Environmental and Natural resources- Public Water Supply Section (DENR-PWSS). Based on EPA’s recommendations, NC regulators have recommended control limits of 0.7-1.0 mg/L of fluoride. Fluoride is received as 25% of Hydrofluosilicic acid. This solution is fed at the final treatment step before the water enters the distribution system.

Liquid Ammonium Sulfate (LAS)

LAS is added at certain proportion with chlorine at the final treatment steps before water leaves the plant. LAS reacts with Hypochlorite (Chlorine) to form mono-chloramines. Mono-chloramines remains with water throughout the distribution system which acts as secondary disinfectant. The advantage of mono-chloramines is that it does not react with organics to form disinfection bi-product (THM) like chlorine does. 

Questions?
The City's drinking water laboratory will provide a professional water analysis upon request. If you have questions about your drinking water, call 336-373-7527.