The use of culture fluorescence monitoring for the control and optimization of biological nutrient removal from wastewater
Creators: name: Mah, Terrance Jock
Publisher: name: University of British Columbia
Year: 2009

description: The objectives of this research were to test the efficacy of continuous real time monitoring of culture fluorescence, associated with intracellular NADH, as an indicator of changes in the biological activity of biological nutrient removal processes, and to determine the usefulness of this tool for the development of control and optimization strategies to improve the efficiency and consistency of biological nutrient removal processes. For that purpose, intensive studies comparing a number of key process variables with culture fluorescence measurements were done at operating pilot and full scale biological nutrient removal facilities. Results demonstrated several consistent relationships between culture fluorescence and specific key variables. The particular relationships between these variables and fluorescence measurements seemed to be affected by process operating configurations. The gross trends in culture fluorescence showed good correlation with process mixed liquor suspended solids levels in each of the process zones, while the smaller, transient changes in fluorescence related to changes in biological activity. Primary effluent culture fluorescence corresponded to VFA concentrations at all of the plants studied. The consistency of the general fluorescence correlations at each plant allowed general changes in primary effluent VFA content to be predicted on a real time basis from the on-line culture fluorescence data. Similarly, consistent patterns were found between anaerobic zone culture fluorescence and changes in specific anaerobic zone VFA consumption, anaerobic zone mass phosphate release, and anaerobic zone PHA storage. The pattern between anaerobic zone culture fluorescence and specific anaerobic VFA consumption demonstrated the strongest correlation. The consistency of all the patterns should allow changes in anaerobic zone biological activity to be predicted from the changes in measured culture fluorescence. Comparison of the relative differences between anaerobic zone and anoxic zone levels of fluorescence provided an indication of biological denitrification activity. The patterns observed between the various parameters and culture fluorescence could each be attributed to specific mechanisms and/or metabolic patterns. The ability to conveniently and rapidly monitor changes in biological activity, using fluorescence monitoring, that altered the process characteristics suggested potential applications for optimizing the biological nutrient removal process through fluorescence-based control. Specifically, these strategies outlined methodology for improving the consistency of effluent phosphorus quality and biological denitrification that involved fluorescence-based regulation of process nutrient load, biological activity, process aeration, and internal recycle control. Preliminary testing at a full scale biological nutrient removal facility demonstrated the ability to achieve continuous, real time nutrient load regulation using culture fluorescence measurements. From the results obtained with pilot and full scale testing, sludge fluorescence is an indicator of changes in biological activity. Continuous monitoring of this fluorescence is useful, real time technology for the development of control and optimization strategies to improve the performance of biological nutrient removal processes.