Understanding Chlorination In Water Treatment

Water has always been a precious resource that is essential for human survival. However, not all water sources are safe for consumption due to harmful microorganisms and contaminants. As a result, different water treatment processes and some advanced water purification systems are utilized to fix the issue. One of the most common methods used in water treatment is chlorination. 

This article explains the concept of chlorination in water treatment, its purpose, and how it works.

What Is Chlorination?

Chlorination is adding chlorine, a powerful disinfectant, to water to kill or inactivate harmful microorganisms such as bacteria, viruses, and protozoan parasites. It is a widely used method for water treatment in municipal water supplies, swimming pools, and other water systems to ensure that the water is safe for human consumption and other uses.

The primary purpose of chlorination in water treatment is to prevent the spread of waterborne diseases. Microorganisms in water can cause illnesses such as cholera, dysentery, and typhoid fever, which can have severe health impacts, especially in developing countries with limited access to clean water. Chlorine effectively kills or inactivates these microorganisms, making the water safe for consumption.

How Chlorination Works

So, how does chlorination work in water treatment? Chlorine can be added to water in different forms, such as chlorine gas (Cl2), sodium hypochlorite (NaClO), or calcium hypochlorite (Ca(ClO)2). When chlorine is added to water, it reacts with water to form hypochlorous acid (HOCl) and hypochlorite ions (OCl-), collectively known as free available chlorine (FAC). These reactive chlorine species attack the microorganisms by disrupting their cell walls and other essential structures, ultimately killing or inactivating them.

Two types of chlorination are: pre-chlorination and post-chlorination. Pre-chlorination involves adding chlorine to water before it enters the treatment process. This helps to disinfect the water and prevent the growth of microorganisms in the treatment equipment and pipelines. On the other hand, post-chlorination involves adding chlorine to water after it has been treated to ensure that it remains disinfected as it travels through the distribution system and reaches the consumers' taps.

How Effective Is Chlorination?

Chlorination is a highly effective method for water disinfection due to its broad-spectrum activity against various microorganisms. It has been proven to reduce the risk of waterborne diseases significantly and has been widely adopted worldwide as a critical step in water treatment processes. However, it is essential to note that chlorination has some limitations. 

For example, the process may not effectively remove certain chemical contaminants or taste and odor issues in water. Moreover, the disinfection byproducts (DBPs) formed during chlorination, such as trihalomethanes (THMs), can pose potential health risks in high concentrations. Therefore, careful monitoring and regulation of chlorine levels and other water quality parameters are crucial to ensure the treated water is safe. Further purification processes, like the reverse osmosis filter system, can also combat these limitations and ensure that the water delivered for consumption is entirely clean and safe.