Chloramines

N-chloropiperidine

Chloramines are chemical compounds that contain the chlorine and nitrogen atoms connected together. They are formed when chlorine is used to disinfect water containing organic nitrogen compounds, leading to the formation of monochloramine, dichloramine, and trichloramine. These compounds are of significant interest due to their applications in water treatment, their effects on water quality, and their implications for public health.

Formation and Types

Chloramines are formed through the reaction of chlorine with ammonia. The process can produce three main types of chloramines:

• Monochloramine (NH2Cl), which is often used in drinking water treatment due to its stability and lower tendency to form disinfection by-products compared to free chlorine.
• Dichloramine (NHCl2), which is more effective as a disinfectant than monochloramine but is also more likely to form unwanted by-products.
• Trichloramine (NCl3), which is not intentionally produced in drinking water treatment due to its strong, unpleasant odor and potential health risks.

Uses

The primary use of chloramines is in water treatment as secondary disinfectants. They are preferred in some systems over chlorine because they provide longer-lasting disinfection as the water moves through pipes to consumers. Chloramines are also less likely to react with organic matter in water to form harmful disinfection by-products, such as trihalomethanes and haloacetic acids, which are linked to cancer and other health problems.

Health and Environmental Impact

While chloramines are effective in controlling pathogens in water supplies, their presence in drinking water has raised concerns regarding potential health effects. Exposure to water that contains chloramines can lead to skin irritation, eye irritation, and respiratory problems for some individuals. Moreover, chloramines can be toxic to aquatic life, necessitating careful management of water discharge from treatment plants.

Regulation and Management

In the United States, the Environmental Protection Agency (EPA) regulates the levels of chloramines in drinking water to ensure safety for human consumption. Water utilities that use chloramines must adhere to specific treatment and monitoring requirements to minimize the formation of harmful by-products and to protect public health.

Removal from Water

Removing chloramines from water requires different methods than those used for chlorine. Techniques such as activated carbon filtration, campden tablets, or ascorbic acid can be effective in reducing chloramine levels for applications such as aquariums, where chloramines can be harmful to fish.

Conclusion

Chloramines play a crucial role in maintaining the safety of drinking water by providing an alternative disinfection method that reduces the formation of harmful by-products. However, their use must be carefully managed to mitigate potential health and environmental impacts. Ongoing research and regulation are essential to ensure that water treatment practices continue to protect public health while minimizing adverse effects.