Innovative technique for analysis of wastewater contaminants using hyperspectral imaging

Accurate, fast, quantitative on-site analysis of wastewater is an environmental necessity. Therefore, we report a quantitative spectroscopic study in order to analyse organic contaminants in wastewater. For this purpose, two spectroscopy-based techniques were utilised and their results are compared. The first technique is ultraviolet/visible (UV/vis) spectrophotometry. This technique is a standard laboratory technique, however, it is inappropriate for working in the field. Besides, the analysis results of the standard laboratory technique display low accuracy in detecting small concentrations of wastewater contaminants such as methylene blue (< 20 ppm). Accordingly, there is a need for another technique to overcome the shortcomings of UV/vis spectrophotometry. Hyperspectral imaging (HSI) combines imaging and spectrometry. HSI works on-site since it is port-able and easy to operate. The analysis of the data acquired by HSI showed a higher efficacy in accurately detecting both low (< 20 ppm) and high concentrations (> 50 ppm) of water contaminants such as methylene blue and methyl orange. For verification, Pearson correlation coefficients were computed between the concentration of contaminants and their absorbance for all the operating spectral bands. The results of the two techniques were statistically compared using Bland and Altman’s limit of agreement. This study showed that HSI is potentially a promising technique for the analysis of wastewater contaminants on-site.