The purpose of disinfection in the treatment of waste water is to substantially reduce the number of microorganisms in the water to be discharged back into the environment for the later use of drinking, bathing, irrigation, etc. The effectiveness of disinfection depends on the quality of the water being treated (e.g., cloudiness, pH, etc.) the type of disinfection being used, the disinfectant dosage (concentration and time), and other environmental variables.
The most common form of waste water disinfection due to its low cost and long-term history of effectiveness .Sodium Hypochlorite solution may be used.
UV light can be used instead of chlorine, or other chemicals. UV radiation causes damage to the genetic structure of bacteria, viruses, and other pathogens, making them incapable of reproduction.
O3 is generated by passing oxygen (O2) through a high voltage potential resulting in a third oxygen atom becoming attached and forming O3. Ozone is very unstable and reactive and oxidizes most organic material it comes in contact with, thereby destroying many pathogenic microorganisms. Ozonator may be used for this system.
|Safty to opraters||Involve strong chemical handling and storage, risk to opraters||minimal chemical handling involved, chemicals are used only occasionally for cleaning lamps|
|Environmental Impacts||Possible formation of disinfection byproducts. Risk of discharge of chlorinated effluent should dechlorination system fail||UV bulbs are returned to a recycler after replacement with new bulbs. Non-toxic effluent|
|Proven Technology||Most commonly used disinfection process for wastewater treatment||Being operated in many small to medium sized wastewater treatment plants with proven success|
|Space Impacts||Larger footprint||Smaller footprint|
|Complexity||Simple process. Chlorination is currently practiced at the plant, therefore operators are familiar with system||Simple process, More operator training required|