CWEA Grade 3 Lab Analyst Practice Exam

The biochemical composition of wastewater is often measured using spectrophotometric analysis due to its ability to quantify concentrations of various compounds in liquid samples by measuring the intensity of light absorbed at specific wavelengths. This method is particularly useful for determining parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), and concentrations of organic and inorganic substances in the water.

Spectrophotometry is favored in wastewater analysis because it is relatively quick, requires minimal sample preparation, and can handle a wide range of concentrations and sample types. This makes it a practical tool for routine monitoring in wastewater treatment facilities.

Other methods, while useful in specific contexts, may not offer the same level of efficiency or direct applicability for the biochemical analysis of wastewater. For example, gas chromatography is typically used for volatile compounds, HPLC (High-Performance Liquid Chromatography) is more suited for complex organic mixtures, and microbial testing focuses on the presence of specific microorganisms rather than providing a broad biochemical profile.