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Water Practice & Technology © IWA Publishing 2008  |  doi:10.2166/wpt.2008.064

Real-Time Efficiency Monitoring for Wastewater Aeration Systems

Shao-Yuan Leu^a, Diego Rosso^b, Pan Jiang^a, Lory E. Larson^c and Michael K. Stenstrom^a

^aCivil and Environmental Engineering Department, 5714 Boelter Hall, University of California, Los Angeles, Los Angeles, CA 90095-1593, U.S.A.
Email: stenstro@seas.ucla.edu
^bCivil and Environmental Engineering Department, University of California, Irvine, CA 92697, U.S.A.
^cSouthern California Edison, Rosemead, CA 91770, U.S.A.

Aeration is the most energy intensive unit operation in municipal wastewater treatment. To improve oxygen transfer rate, fine-pore diffusers have been wildly applied in aeration practice. However, during operation, this type of diffuser suffers from fouling and scaling problems, which cause a rapid decline in aeration performance and significant increase in energy consumption. Diffusers must be cleaned periodically to reduce energy costs. The cleaning frequency of diffusers is site-specific, and can be evaluated by oxygen transfer efficiency (OTE) measurements over time in operation. Off-gas testing is the only technique that directly measures oxygen transfer efficiency in real-time. This paper presents a time-series of off-gas measurements which demonstrate the value of implementing energy-conservation practices. Our results include the real-time prediction of plant load and alpha factors from off-gas testing, as well as the quantification of the increased energy costs caused by fouling. Our off-gas analyzer can be used to develop an aeration efficiency monitoring protocols, and an aeration feedback control system for blowers.

Keywords: Aeration; off-gas technique; oxygen-transfer efficiency

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