THE STEP BIO-P PROCESS AT LETHBRIDGE — OVER ONE FULL YEAR OF OPERATION

In 1998, the City of Lethbridge completed an extensive plant upgrade program in order to meet strict ammonia and phosphorus requirements. The plant was commissioned in late 1998 as a full-scale Step Bio-P facility, after having retrofitted the plant to a new process that includes BNR in combination with step feed technology. Of interest, the plant receives significant loads from local food processing industries, and in particular a seasonal corn processor. The plant was in startup mode during the first (1998) corn processing season. Peak seasonal load conditions were therefore encountered for the first time during autumn of 1999, during which time extensive analyses of the plant performance and operation were conducted. This facility has now been operated and intensively studied for over one year, and data is now available to analyze the process under various conditions.This paper will provide a detailed analysis of the first 16 months of operation at Lethbridge, including an intensive review of the seasonal effect of the corn processing loads on process performance. The lessons learned from the successful operation in Lethbridge will benefit other plants that may wish to consider this innovative upgrade technology.