Disinfection of Water Using Chemicals and UV
Clean, safe drinking water is essential for public health, industrial applications, and agricultural needs. However, untreated or poorly treated water can contain harmful pathogens such as bacteria, viruses, and protozoa, which pose serious health risks. To mitigate these risks, various methods of disinfection of water are employed worldwide. Among these, chemical disinfection of water and ultraviolet disinfection of water are two of the most widely used and effective solutions.
This article explores the principles, applications, advantages, and limitations of disinfection of water using chemicals and UV technologies.
Why Disinfection of Water Is Critical?
Disinfection is the final barrier in the water treatment process and ensures that the water reaching end users is microbiologically safe. The primary goal is to destroy or inactivate pathogenic microorganisms that can cause diseases such as cholera, dysentery, and hepatitis. Without proper disinfection, even treated water can become a source of contamination during storage or distribution.
Common Methods of Disinfection
There are several methods of disinfection used in water treatment systems across the globe. These include:
- Boiling (in small-scale or emergency)
- Filtration with disinfection (such as ultrafiltration combined with UV or chemicals)
- Chemical disinfection of water
- Ultraviolet disinfection of water
While boiling and filtration can remove many contaminants, they are often impractical at scale. Hence, disinfection of water by chlorine and UV treatment has emerged as a reliable and scalable technology.
Chemical Disinfection of Water
Chemical disinfection of water primarily involves the use of oxidizing agents that kill or deactivate pathogens. The most commonly used chemical is chlorine, although others such as chloramine, chlorine dioxide, and ozone are also used in specific applications.
Disinfection of Water by Chlorine
Disinfection of water by chlorine is one of the most traditional and widely used practices globally. Chlorine is effective against a broad spectrum of pathogens and leaves a residual concentration in the water, offering continued protection during storage and distribution.
Advantages:
- Effective against bacteria and viruses
- Economical and easy to apply
- Provides residual disinfection
Limitations:
- Less effective against certain protozoa, like Cryptosporidium
- Can form disinfection by-products (DBPs) like trihalomethanes (THMs), which may be harmful in high concentrations
- Taste and odor concerns
Despite its limitations, chemical disinfection of water using chlorine continues to be a preferred method for municipal and industrial water treatment due to its reliability and simplicity.
Ultraviolet Disinfection of Water
Ultraviolet disinfection of water is a physical process that uses UV-C light (wavelengths between 200–280 nm) to inactivate microorganisms by damaging their DNA or RNA. This method does not involve the addition of any chemicals, making it an environmentally friendly option.
UV systems are often installed as a final disinfection step, especially in systems where chemical residues are undesirable, such as food and beverage processing, pharmaceuticals, or in eco-sensitive areas.
Advantages:
- No chemical usage or by-products
- Effective against bacteria, viruses, and protozoa (including chlorine-resistant strains)
- Rapid disinfection with minimal contact time
- Minimal alteration to the taste or smell of water
Limitations:
- No residual disinfection, so post-treatment contamination must be prevented
- Requires clear water for optimal UV transmission
- Higher upfront costs compared to chlorine systems
While UV disinfection alone cannot provide residual protection, it is often used in combination with chemical disinfectants for comprehensive control, particularly in advanced treatment plants.
Comparing UV and Chemical Disinfection
Both chemical disinfection of water and ultraviolet disinfection of water have their place in modern water treatment processes. The choice between them depends on various factors such as:
- Water quality and clarity
- Presence of specific pathogens
- Regulatory standards
- Infrastructure and operational capacity
- Cost considerations
In many advanced water treatment systems, a hybrid approach is adopted where UV is used for primary disinfection, followed by chlorine for residual protection throughout the distribution network.
Applications Across Sectors
These methods of disinfection of water are not limited to municipal use. They are critical across industries such as:
- Pharmaceuticals: Where ultrapure water is required
- Food & Beverage: Ensuring product safety without chemical residue
- Power Plants: For boiler feed water treatment
- Hospitals & Laboratories: Where microbial control is paramount
- Residential Systems: UV units are increasingly used in homes for point-of-entry or point-of-use disinfection
Reliable and Cost-Effective Disinfection with INDION CHLOGEN Chlorine Dioxide Generator
Ion Exchange offers advanced disinfection solutions combining high performance with cost-efficiency and low maintenance. Among these, the INDION CHLOGEN Chlorine Dioxide Generator stands out for its safe, simple, and effective production of chlorine dioxide. Designed for ease of operation and reduced operational cost, CHLOGEN is suitable for industries such as dairy, beverage, pulp and paper, food processing, poultry, textile, hospitals, and more. It comes equipped with features like HAZOP study compliance, high generation efficiency, auto/manual operation modes, and minimal chlorine residuals. It supports both gas and acid-based production technologies, offering a capacity range from 0.4 kg/h to 1 kg/h.Â
The system delivers efficient bio-dispersant and microbial control, approved for drinking water treatment, with a long shelf life and less corrosiveness. Notably, it does not form harmful trihalomethanes (THMs) or react with bromides and ammonia, enhancing overall disinfection effectiveness. Ion Exchange also provides a range of disinfection methods, including chlorine, electrochlorination, ozone, hydrogen peroxide, ultraviolet radiation, and thermal techniques like boiling and steaming, making it a one-stop solution for potable, wastewater, and process water disinfection.
Conclusion
Safe drinking water is a cornerstone of health, industry, and sustainable development. The disinfection of water, whether through chemical disinfection of water methods like chlorination or ultraviolet disinfection of water plays a vital role in ensuring its safety. While each approach has distinct benefits and limitations, their combined use can offer a robust solution for a wide variety of applications.
As water quality standards become more stringent and environmental sustainability gains priority, choosing the right methods of disinfection of water is more important than ever. Whether you’re setting up a municipal treatment plant, an industrial water system, or a residential purification unit, expert guidance is essential.
