CWEA Grade 3 Lab Analyst Practice Exam 2025 – Complete Prep Guide

The technique of filtration followed by gravimetric analysis is the established method for quantifying total suspended solids (TSS) in water. This process involves passing a defined volume of water through a filter that retains suspended solids. After filtration, the solids collected on the filter are dried to remove moisture and then weighed. The difference in mass before and after filtration provides a direct measure of the total suspended solids in the water sample.

This method is preferred for its accuracy and reliability because it allows for the direct measurement of solids without interference from other components. Other techniques may involve complex procedures that are not specifically tailored for quantifying TSS or may not provide a direct measurement of the solid material. For instance, colorimetric analysis followed by electron microscopy is not a common method for TSS as it is more suitable for analyzing specific compounds rather than total solids. Similarly, digestive sampling followed by spectrophotometry or centrifugation followed by pH measurement do not directly target the mass of suspended solids and, therefore, are not adequate methods for this analysis.