Abstract: This disclosure relates to an apparatus for measuring the transmittance of several wavelengths of light through a liquid sample in order to measure or estimate established and novel quality parameters that are descriptive of the quality of the liquid being monitored. The apparatus comprises at least two light emitting diode (LED) modules; each comprising an LED light source and a beam splitter window; a cylindrical rigid structure, a mounting structure, a window aperture, a mechanism for fixing the position of the LED modules, at least one LED light detector, a liquid sample light detector, a microprocessor, and an enclosing structure surrounding the apparatus. The apparatus provides a means for fine tuning the alignment of the light beams generated by the LED light sources, which ensures that the light beams are propagated optimally within the apparatus body and measured accurately by the light detectors.

Abstract: Monitoring and detection of algae in surface water and wastewater is of significant importance, yet there is currently no quick and simple method to achieve this. The present work illustrates a new method to determine the concentration of algae in water and wastewater samples using spectrophotometry, the first derivative of absorbance, and a smoothing technique applied to the first derivative of absorbance (e.g. Savitzky-Golay). The relationship between algal concentration and absorbance for three types of water samples (distilled, surface, and wastewater) was determined in the visible wavelength range, and the effect of using the first derivative of absorbance method on improving algal concentration detection limit was established. Using the first derivative of absorbance method improves algal detection limits, reduces the effect of background absorbance and the resolution of overlapping spectra.

Abstract: Monitoring and detection of algae in surface water and wastewater is of significant importance, yet there is currently no quick and simple method to achieve this. The present work illustrates a new method to determine the concentration of algae in water and wastewater samples using spectrophotometry, the first derivative of absorbance, and a smoothing technique applied to the first derivative of absorbance (e.g. Savitzky-Golay). The relationship between algal concentration and absorbance for three types of water samples (distilled, surface, and wastewater) was determined in the visible wavelength range, and the effect of using the first derivative of absorbance method on improving algal concentration detection limit was established. Using the first derivative of absorbance method improves algal detection limits, reduces the effect of background absorbance and the resolution of overlapping spectra.