Anlysis Of Water Quality Measuring And Sludge Characteristics By Means Of UV And Fluorescence Spectroscopy

Water quality measuring plays an important role in sewage treatment processes.Traditional measuring methods are mainly chemical methods. The measuring processesof chemical methods are complex, time-consuming and consume more chemicals evensome of which are dangerous substance. Spectroscopy measurement have beengradually used in water treatment process in the past two decades since the process issimple, fast, does not require the consumption of chemical reagents and is easy todevelop on-line measurement, etc.This paper study feasibility of using spectroscopy to characterize the concentrationof pollutants, sludge characteristics and control of water treatment process byfluorescence spectrophotometer, UV-visible spectrophotometer combined withmeasuring water quality parameters and kinetic parameters. The contents and results ofthe research are as follows:(1) A model is achieved by partial least squares for UV spectrum to predictconcentration of COD and nitrate in domestic sewage. R2for COD is0.8753. R2fornitrate nitrogen is0.9526. The results show UV spectroscopy can realize forecast ofnitrate nitrogen and COD concentration.(2) In endogenous respiration process, fluorescence and UV spectrumcharacteristics are as follows: during the rapid decline period of endogenous respiration,humic acid peak fluorescence intensity increases4.9%, excitation and emissionwavelengths appeare5nm,6nm blue shift, respectively, f450/500is decreased by9.3%,humification index HIX is increased by4.9%, the peak of UV spectrum has7nmredshift, UV spectrum absorbance increases; during the slow decline period of endogenous respiration, humic peak fluorescence intensity is increased by13.6%,f450/500is increased by4.7%, HIX is decreased by3.5%, UV spectrum absorbanceincreases; during endogenous respiration stable period, humic acid peak fluorescenceintensity is substantially unchanged, f450/500is decreased by4.2%, HIX is increased by29.8%, UV spectrum absorbance increases.(3) Fluorescence spectra of water samples from sewage plant shows that thefluorescence spectra have microbial metabolite peak and humic peak. Changes aboutfluorescence intensity and peak position are mainly turn out in the anaerobic tank.Thechanges are as follows: excitation and emission wavelength of humic acid peak has redshift of5nm and11nm, respectively. Microbial metabolite peak is reduced by67%. theexcitation and emission wavelength has blue shift of5nm and4nm, respectively.(4) In A2/O reactor, protein-like peak is reduced order to anaerobic tank, anoxictank and aerobic tank. Excitation wavelength of protein-like fluorescence peak appears5nm blue shift in anoxic tank. For SBR reactor, excitation wavelength of protein-likepeak has10nm blueshift, humic peak excitation wavelength has5nm redshift, andprotein-like peak and humic acid peak increase after aerating60min. After aerating120min, excitation wavelength of protein-like peak has10nm redshift, excitationwavelength of humic peak has10nm blueshift, fluorescence intensity of protein-likepeak and humic acid peak fall.