Performance Enhancement of a BNR Wastewater Treatment Facility Utilizing a Microcosm Reactor Equipped With a Biological Activity Meter B. R. Schwegler, Jr. Walt Disney Imagineering* J. W. Hubbard, Reedy Creek Energy Services, Inc. R. C. Kirkpatrick, Reedy Creek Energy Services, Inc. T. W. McKim, Reedy Creek Energy Services, Inc. 1. Walt Disney Imagineering, 1401 Flower St., Glendale, CA 91221 Abstract Many domestic wastewater treatment facilities (WWTF) are now using biological nutrient removal (BNR) technologies to meet increasingly stringent effluent nutrient discharge standards. While BNR processes can be both effective and economical, they often are difficult to control due to the temporally dynamic nature of domestic wastewaters, with respect to both flow and composition. A number of sensor technologies and process models recently have been developed to enhance process monitoring and capabilities of BNR facilities. In this manuscript, we describe the use of a Biological Activity Meter (BAM) to enhance performance of the Reedy Creek Improvement District (RCID) 5-stage Bardenpho WWTF. The RCID WWTF has four identical process trains, each consisting of a series of cascading continuously stirred tank reactors. Upon plant commissioning in 1993, the influent wastewater flow averaged 31,600 m3/day (8.35 MGD), substantially higher than the 18,900 m3/day (5 MGD) rating of each process train. Initial operations using both one and two process trains were unsatisfactory: effluent quality met permit guidelines, but the nitrogen (N) removal processes were unstable. In an attempt to better control biological N and phosphorous (P) removal, we deployed BAM units at three locations in the BNR. A BAM is a small, computer-controlled, in situ batch reactor that can capture, isolate and analyze a sample of the mixed liquor. The BAM is equipped with an optical probe that measures biological activity based on microbial NAD(P)H fluorescence. We used data from the BAM unit to manipulate several processes, including the return location and flow rate of the internally recycled mixed liquor. Through process enhancement, we have now successfully operated with one treatment train up to flows of 46,600 m3/day (12.3 MGD), which in turn has provided substantial operational cost savings.