What are Total Fixed Solids (TFS) used to determine?

Total Fixed Solids (TFS) refer to the portion of solids that remains after a sample is evaporated and then ignited. This analytical process determines the weight of solids that do not volatilize at high temperatures, distinguishing them from volatile solids, which can include organic materials that may be lost during the ignition process.

Understanding TFS is crucial in various fields such as water quality assessment and treatment processes, where it helps quantify the amount of non-volatile components left in a sample after it is subjected to heat. This information can be used to assess the quality of wastewater and other water bodies, contributing to appropriate treatment methods and regulatory compliance.

In contrast, the other options focus on different aspects of solid measurements in water. For example, the concentration of dissolved solids addresses characteristics associated with materials that do not settle out. The effectiveness of disinfection involves microbial assessments, which do not relate directly to TFS measurements. Similarly, the total volume of settled solids pertains to sedimentation processes rather than the fixed solid content that remains after ignition. Therefore, the weight of solids remaining after the ignition process aligns perfectly with the definition and purpose of measuring Total Fixed Solids.