| Summary: | 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. === Applied Science, Faculty of === Civil Engineering, Department of === Graduate
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