Ammonia‐Based Feedforward and Feedback Aeration Control in Activated Sludge Processes. (1st January 2014)

• Record Type: Journal Article
• Authors: Rieger, Leiv; Jones, Richard M.; Dold, Peter L.; Bott, Charles B.
• Is Part Of: Water environment research. Volume 86:Number 1(2014)
• Page Start: 63
• Page End: 73
• Publication Date: 2014-01-01
• Subjects: aeration control -- ammonia‐based control -- feedforward control -- feedback control -- energy savings -- wastewater treatment; Water quality management -- Periodicals; Water -- Purification -- Periodicals; Water -- Pollution -- Periodicals; Water -- Pollution; Water -- Purification; Water quality management; Sewage; Water Pollution; Periodicals; Electronic journals; Periodicals; 628.16
• DOI: 10.2175/106143013X13596524516987
• Languages: English
• ISSNs: 1061-4303

Abstract

ABSTRACT: Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio‐P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia‐based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.