AERATED ACTIVATED SLUDGE BASICS
Successful BOD removal in an activated sludge process depends on studying and controlling some basics such as wastewater characteristics.
Aeration is used to operate activated sludge process units and is perhaps the most frequently used process to remove biochemical oxygen demand (BOD) from wastewater. Successful BOD removal in an activated sludge process depends on studying and controlling some basics – such as wastewater sources and quantities, wastewater characteristics, and needed execution in any required preliminary and primary treatment. After performing these operations, the primary treated wastewater entering the activated sludge system achieves BOD removal based on the details below.
The activated sludge process is a biological wastewater treatment operation. This means that treatment occurs through many different microorganisms using pollutants as a food source. It is a suspended growth process – since the organisms are suspended in wastewater rather than attached to a medium, as they are in a trickling filter or rotating biological contact process. Since this is a biological process, understanding some basic biology is useful.
Some organism terms and definitions that should be known are:
Anaerobic – needs no dissolved oxygen (DO) or nitrate oxygen
Aerobic – must have DO
Facultative – can exist with or without DO
Heterotrophic – consumes organics in the wastewater
Autotrophic – able to use inorganic compounds as a food source