In Medium and Low Strength Organic Wastewater Treatment, activated sludge process is one of the most widely used methods with the most reliable operation. Its technology is mature, with relatively broad technical divisions. Besides, it has the advantages as investment-saving, easy to start up and good process effect and so on.
       However, since the activated sludge method consumpts lots of energy in aeration, leading to terribly high processing expenditure, while the aeration in the air will easily produce foam, which is hard for oxygenation, and easily produce sludge bulking once there is bad management,thus limits its application.