Application of multi-wavelength fluorometry for monitoring wastewater treatment process dynamics

• Published in: Water research (Oxford) 1996-12, Vol.30 (12), p.2941-2948
• Main Authors: Tartakovsky, Boris, Lishman, Lori A., Legge, Raymond L.
• Format: Article
• Language: English
• Subjects: activated sludge process; Applied sciences; Biological and medical sciences; Biological treatment of waters; bioprocess monitoring; Biotechnology; Environment and pollution; Exact sciences and technology; fluorescent spectroscopy; Fundamental and applied biological sciences. Psychology; General purification processes; Industrial applications and implications. Economical aspects; Pollution; regression analysis; wastewater treatment; Wastewaters; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(96)00196-0

Much of the methodology employed for characterizing wastewater and in modeling wastewater treatment processes employs off-line analysis. Off-line analysis is time consuming and not ideally suited to developing process control strategies. Clearly a rapid, inexpensive and reliable method suitable for following organic consumption and biomass production on-line would be very useful. In this study multiple excitation—multiple emission fluorometry was examined as a method for monitoring wastewater treatment processes. Results were first obtained for defined protein solutions and activated sludge to identify characteristic excitation and emission wavelength pairs. These results were then used to develop a rapid off-line assay for measurement of synthetic feeds consisting of protein substrates for batch aerobic and anoxic wastewater treatment processes and for on-line monitoring of cellular metabolic states in an anoxic process. Step-wise multiple regression and principal component analysis were employed for data analysis. The former was used to determine the most informative excitation and emission wavelength pairs while the latter was applied to reduce fluorescent spectra dimensions. Analysis of the batch kinetics suggests that this approach is valid and revealed some dynamic features of protein utilization and biomass accumulation under aerobic and anoxic conditions. A correlation was developed between COD-removal rates and the fluorescence signals in the two processes using fluorescent emission spectra rather than single signals. The data suggests that this multiple excitation—multiple emission fluorometry may be a suitable method for following wastewater and activated sludge dynamics and could be used as the basis for the development of expert system based biosensors.