Actibated Sludge

Activated sludge is a common method used to biologically treat municipal wastewater. The method was first developed in England in the early 1900’s. In 1912, H. W. Clarke studied the use of microorganisms in the purification of sewage through aeration. Edward Arden and William Lockett followed by carrying out similar experiments. They determined that high levels of purification could be reached through this biological process. They also integrated the use of recycle to the aeration stage. Arden and Lockett reported their findings to the Society of Chemical Industry in 19142. Since then, the theory of activated sludge as a wastewater treatment process has continued to develop in small steps to the present day.
The activated sludge method typically consists of a well-agitated and aerated reactor and a settling tank. Depending on the design, the reactor can either model a plug-flow reactor, or a CFSTR. If the reactor is designed to be long and narrow, it will model a PFR...