ABSTRACT
After secondary treatment to remove BOD 5 and solids, wastewater may still contain large numbers of microorganisms. Some of these microbes may be pathogenic and may cause epidemics if discharged to the receiving waters. Wastewater treatment functions to reduce the possibility of this happening. As with other steps (unit processes) of treatment, there are many processes available to achieve disinfection. The most widely used process is chlorination. Other processes include ultraviolet (UV) light, ozonation (ozone treatment), and bromine chloride addi tions. Only the chlorination process is discussed in Volume 1 of this handbook; the other disinfection processes are covered in Volumes 2 and 3.
