Difference between Free Chlorine and Total Chlorine
Chlorine is a commonly used disinfectant in water treatment plants, swimming pools, and other water-based environments. It plays a crucial role in eliminating harmful bacteria, viruses, and other pathogens that can cause diseases. However, there are two types of chlorine that are often used and measured in water quality testing: free chlorine and total chlorine. Understanding the difference between these two is essential for maintaining safe and healthy water conditions.
Free Chlorine
Free chlorine refers to the chlorine that is not combined with other substances in the water. It is the most active form of chlorine and is responsible for the disinfection process. Free chlorine can effectively kill pathogens and prevent them from re-growth. The concentration of free chlorine in water is typically measured in parts per million (ppm) and is considered to be the most accurate indicator of water quality.
Total Chlorine
Total chlorine, on the other hand, is the sum of free chlorine and combined chlorine. Combined chlorine refers to the chlorine that has reacted with organic matter, such as ammonia or organic nitrogen, in the water. This reaction forms chloramines, which are less effective at killing pathogens compared to free chlorine. Total chlorine is also measured in ppm and is used to assess the overall chlorine level in water.
Key Differences
The main difference between free chlorine and total chlorine lies in their effectiveness and stability. Free chlorine is more potent and can quickly eliminate pathogens, while combined chlorine is less effective and can persist in the water for a longer period. Here are some key differences between the two:
1. Disinfection: Free chlorine is more effective at killing pathogens, making it the preferred choice for water disinfection. Combined chlorine, on the other hand, is less effective and can contribute to the growth of some bacteria.
2. Stability: Free chlorine is highly reactive and can be easily degraded by sunlight, organic matter, and other chemicals in the water. Combined chlorine is more stable and can remain in the water for an extended period.
3. Measurement: Free chlorine is measured directly, while total chlorine is measured by adding the concentration of free chlorine and combined chlorine. This means that total chlorine can provide a more comprehensive picture of the chlorine level in water.
4. Health Risks: High levels of combined chlorine can cause irritation to the skin, eyes, and respiratory system. Free chlorine, when used in appropriate concentrations, is generally considered safe for human consumption.
Conclusion
In conclusion, the difference between free chlorine and total chlorine is significant in terms of their effectiveness, stability, and health risks. While free chlorine is the most potent form of chlorine and is crucial for water disinfection, total chlorine provides a more comprehensive assessment of the chlorine level in water. Understanding these differences is essential for maintaining safe and healthy water conditions in various applications.
