20pts) Discuss the advantages and disadvantages of using chlorine as a disinfectant and also name east two alternative disinfectants for drinking water treatment. Solution Advantages of chlorination 1. Chlorine is a powerful oxidizing agent thereby kills bacteria and fungi in water. 2. Chlorine is commercially available 3. Chlorine is very economical 4. chlorine is more cost-effective than other disinfection methods (except when dechlorination is needed and fire code requirements must be met). 5. The chlorine residual that remains in the discharged wastewater can prolong disinfection even after initial treatment and also provides a measure of the effectiveness. Disadvantages 1. The chlorine residual, even at low concentrations, is toxic to aquatic life and may require dechlorination. 2. All forms of chlorine are highly corrosive and toxic. Thus, storage, shipping, and handling pose safety risks. 3. Chlorine oxidizes organic matter in wastewater, sometimes creating compounds that could be harmful to humans and the environment. 4. The chloride content of the wastewater is increased. 5. Certain types of microorganisms have shown resistance to low doses of chlorine. 6. The long-term effects of discharging dechlorinated compounds into the environment are unknown. In addition to chlorination there are many methods. Few of them are 1. OZONALYSIS (Addition of ozone) 2. Boiling. (Boiling water is the cheapest and safest method of water purification.) .. .

1. 20pts) Discuss the advantages and disadvantages of using chlorine as a disinfectant and also
name east two alternative disinfectants for drinking water treatment.
Solution
Advantages of chlorination
1. Chlorine is a powerful oxidizing agent thereby kills bacteria and fungi in water.
2. Chlorine is commercially available
3. Chlorine is very economical
4. chlorine is more cost-effective than other disinfection methods (except when dechlorination is
needed and fire code requirements must be met).
5. The chlorine residual that remains in the discharged wastewater can prolong disinfection even
after initial treatment and also provides a measure of the effectiveness.
Disadvantages
1. The chlorine residual, even at low concentrations, is toxic to aquatic life and may require
dechlorination.
2. All forms of chlorine are highly corrosive and toxic. Thus, storage, shipping, and handling
pose safety risks.
3. Chlorine oxidizes organic matter in wastewater, sometimes creating compounds that could be
harmful to humans and the environment.
4. The chloride content of the wastewater is increased.
5. Certain types of microorganisms have shown resistance to low doses of chlorine.
6. The long-term effects of discharging dechlorinated compounds into the environment are
unknown.

2. In addition to chlorination there are many methods. Few of them are
1. OZONALYSIS (Addition of ozone)
2. Boiling. (Boiling water is the cheapest and safest method of water purification.) ..