Anaerobic / aerobic activated sludge treatment method and apparatus

摘要

PROBLEM TO BE SOLVED: To provide an anaerobic and aerobic activated sludge treating method which is capable of stably maintaining the good removal of a BOD component and nutrient salt component for a long period. SOLUTION: The device is provided with a second activated sludge treating vessel 3 in communication with a first activated sludge treating vessel 2 into which a water to be treated flows continuously. The respective treating vessels are provided with aerators 14 and 24 for putting the inside of the treating vessels into an aerobic or anaerobic state by the aeration quantity or aeration stoppage meeting an input control signal. The respective treating vessels are provided with pH meters 11 and 21, DO meters 12 and 22 and ORP meters 13 and 23 and pH maximal point detecting means 17 and 27 with noise removal filters are connected to the respective pH meters. A calculating means 28 for a DO decreasing rate in the anaerobic state is connected to the DO meter of the second treating vessel. The fuzzy control rule 33 having each of the anaerobic and aerobic states of the respective treating vessels, the time for detection of the pH, DO, ORP and pH maximal point and the DO decreasing rate of the second treating vessel 3 as a precondition part variable and the aeration quantity of the aerators 15 and 25 as a post condition part variable is stored into a controller 30. The switching of the anaerobic and aerobic states of the respective treating vessels and the adequate aeration quantity are controlled in accordance with the control rule 33.