<title>Laser scattering technique for noninvasive analysis of wastewater</title>

Abstract

Fluorescence spectra of final effluent samples from three sewage treatment plants show a remarkable similarity. For raw sewage samples, the fluorescence intensity is comparatively much higher than those of the final effluent and varies from sample to sample, although the spectral shapes are very similar. Fluorescence spectra of both raw sewage and final effluent samples, collected periodically over an eight-month period were recorded, and the UV- absorbance, pH, and conductivity of each sample were measured. The water Raman normalized fluorescence intensities of the samples from a particular plant at 350 nm emission wavelength are found to be correlated with the corresponding biochemical oxygen demand (BOD<SUB>5</SUB>) values. When appropriate correction for chemical and environmental parameters are applied to the fluorescence data, the technique is considered to be suitable for real-time assessment of biodegradable carbon loading in sewage treatment plants for on-line process control.