Disinfection Process in Water Treatment
The filtered water obtained after filtration may still contain harmful disease-causing microorganisms and bacteria. These microorganisms must be destroyed to make the water safe for drinking purposes.
The chemicals or methods used to destroy harmful microorganisms are called disinfectants, and the process is known as disinfection.
Disinfection is one of the most important final stages of the water treatment process, as it helps prevent waterborne diseases and ensures a safe and reliable drinking water supply.
Objectives of Disinfection
– To destroy harmful bacteria, viruses, and other microorganisms
– To make water safe for human consumption
– To prevent waterborne diseases
– To maintain hygienic water quality during storage and distribution
Types of Disinfection Methods
- Chlorine Gas Disinfection :Chlorine gas is widely used in large water treatment plants for disinfection. It is highly effective in killing bacteria and maintaining residual chlorine throughout the water distribution system.
- Chlorination Using Sodium Hypochlorite : In this method, sodium hypochlorite solution is used as a disinfectant. It is commonly used in small treatment plants, industries, and water storage tanks.
- Chlorination Using Calcium Hypochlorite : Calcium hypochlorite is available in solid form and is commonly used for disinfection in rural water supply systems, swimming pools, and emergency water treatment applications.
- Chlorine Dioxide (ClO₂): Chlorine dioxide is an effective disinfectant used to control bacteria, viruses, as well as odour and taste problems in water.
- Hydrogen Peroxide (H₂O₂) : Hydrogen peroxide is used as an oxidising and disinfecting agent in specific water treatment applications.
- Ozonation : Ozone is a powerful oxidising agent used for water disinfection. It effectively destroys microorganisms and improves water quality without leaving harmful residues.
- Ultraviolet (UV) Disinfection : UV disinfection uses ultraviolet light to destroy bacteria, viruses, and other microorganisms. It is a chemical-free disinfection method that is widely used in modern water treatment systems.
Importance of Disinfection
Disinfection is essential because untreated or partially treated water can spread serious waterborne diseases, such as:
– Cholera
– Typhoid
– Dysentery
– Diarrhoea
Therefore, proper disinfection plays a vital role in providing safe, clean, and healthy drinking water for the public while protecting public health and ensuring the effectiveness of the water treatment process.
Mr. Prashant Walke
Trainer & Coordinator
Water & Wastewater Management Course
AISSMS College of Engineering, Pune