ABSTRACT
Th e r e are a number of kinds of sewage that come to the treatment plants. Domestic waste is what most people think of. This is all the wastewater that comes from the household. Manufacturing plants will con tribute industrial waste. This could contain dissolved metals from a plating company or heavy organic materials from a jelly factory. In these cases the company may have to pretreat their waste to reduce the heavy loading on the wastewater treatment plant. The combination of domestic waste and industrial waste is called municipal waste. A sewer that contains only municipal waste is known as a sanitary sewer (see Figure 1.1).
