Abstract: A system for controlling the aerobic phase of a wastewater treatment cycle in a sequencing batch reactor, comprising a tank, an air blower, at least one sensor for measuring the concentration of dissolved oxygen in the tank, and means to control the length of time that the air blower introduces air into the wastewater and to maintain at a constant level the volume of air introduced per time by the air blower. The length of time that the air blower introduces air is determined by the change in the slope of the curve representing the concentration of dissolved oxygen in the wastewater. The volume of air to be introduced per time by the air blower is determined based on the average concentration of dissolved oxygen from the previous wastewater treatment cycle.

Abstract: A system for controlling the aerobic phase of a wastewater treatment cycle in a sequencing batch reactor, comprising a tank, an air blower, at least one sensor for measuring the concentration of dissolved oxygen in the tank, and means to control the length of time that the air blower introduces air into the wastewater and to maintain at a constant level the volume of air introduced per time by the air blower. The length of time that the air blower introduces air is determined by the change in the slope of the curve representing the concentration of dissolved oxygen in the wastewater. The volume of air to be introduced per time by the air blower is determined based on the average concentration of dissolved oxygen from the previous wastewater treatment cycle.

Abstract: In a data communications system, including an infrastructure arranged to communicate over a data channel with a plurality of data terminals, a method of detecting data decryption errors in a data packet includes receiving an encrypted data packet (213); decrypting the encrypted data packet to provide a decrypted data packet; and comparing a reference value to a portion of the decrypted data packet to determine when a predetermined relationship is satisfied (221).

Abstract: In a data communication system (100) including infrastructure (101) arranged to communicate with a plurality of terminals (103) over a channel (109), a method of adaptable channel access practiced at a terminal (103) including determining an access priority value (303), responsive thereto ascertaining when the channel is available (305), and then executing a channel access attempt (307). The access priority value is determined with information received by the terminal or information available to the terminal.