Disinfection
One of the most viable of primary techniques designed for destructing and inactivating pathogenic organisms or microbes in a sample like domestic wastewater is disinfection – a process that minimizes or impedes the spread of waterborne diseases to downstream users and the environment. Harmful organisms that  usually thrive in municipal/domestic wastewater are pathogenic enteric bacteria, viruses, helminthes and their eggs, and protozoan cysts – all of which are bearers of many dangerous waterborne diseases such as typhoid and paratyphoid fever, cholera, bacillary dysentery, giardiasis, crytosporidiosis, amoebic dysentery, poliomyelitis, infectious hepatitis, aseptic meningitis, encephalitis, gastroenteritis, and chronic anemia. Disinfection as a sterilizing method helps in reducing the number of pathogens in the wastewater stream so that the risk of all these diseases are minimized to a great extent.
Common Disinfection Methods Boiling
This is probably the most simple of all disinfection processes. Here, harmful bacteria present in water is effectively destructed by boiling the water at a high temperature. However, the process is not suitable for purifying huge amounts of water. The process also does not warrant against possible future contamination.
Treatment with Excess Lime
Lime when added to water increases its pH value and makes it extremely alkaline. This extreme alkalinity disrupts growth and survival of bacteria in the treated water. This method should however be followed by treatment like recarbonation for lime removal, before the treated water is supplied for drinking or cooking to the general public.
Treatment with Ozone
Ozone easily breaks down into normal oxygen, liberating nascent oxygen in the process. This nascent oxygen is a very strong oxidizing agent that helps in eliminating harmful bacteria from the water. Ozone is used as a primary disinfectant in many countries.
Chlorination
Chlorine acts as an excellent disinfectant in the solid, liquid as well as the gaseous form. Chlorine when used as a disinfectant penetrates the cell walls of bacteria and disrupts the enzymes which are imperative for the metabolic processes of living organisms.
UV Radiation
UV radiation is another disinfection method that effectively destroys pathogenic bacteria and viruses by disrupting the biological processes and reproduction. This disinfection method is preferred by most people as it is relatively simple, produces no known toxic residuals, and requires short contact times. This method is however not suitable for purifying water that has high levels of turbidity, color, suspended solids or soluble organic matter.
Factors Affecting Disinfection
A few factors that affect the disinfection process of wastewater are:
- Contact time
- pH
- Concentration
- Type of disinfectant used
- Wastewater demand
- Wastewater temperature
- Flow rate
- Presence and concentration of interfering substances.
|
Home 
Contact Us
Sitemap
is continually depleting with its increasing demand. Key reasons that account for the growing demand of water.