Patent ID: 6743362
Filing Date: 2004-06-01
Classification: C02F,Y02W,Y10S

Abstract:
In a sewage treatment plant and process having a liquid side in which nitrogen removal is effected, a method of operating the liquid side of the treatment process so as to effect nitrification and denitrification within a single tank and simultaneously to remove water, comprising:maintaining an aerobic/anoxic zone in a tank receiving plant influent wastewater, wherein nitrification and denitrification occur simultaneously and continuously, maintaining dissolved oxygen concentration in the aerobic/anoxic zone in a fluctuating range, allowing dissolved oxygen concentration to approach the lower end of said range and monitoring the status of bacteria in the aerobic/anoxic zone and detecting when some of the bacteria in the zone turn anaerobic, after the anaerobic condition has been detected, increasing dissolved oxygen in the aerobic/anoxic zone by increasing aeration to promote nitrification with the formation of nitrates, then reducing aeration to the aerobic/anoxic zone to an extent to allow the bacteria to consume dissolved oxygen and then to consume nitrates in a denitrification cycle, releasing nitrogen gas, repeating the steps of monitoring, increasing dissolved oxygen and reducing aeration, and simultaneously removing filtrate water from the wastewater in the aerobic/anoxic zone while conducting the above steps, using at least one membrane separator in the aerobic/anoxic zone, whereby need for separate clarification on the liquid side of the plant is eliminated.