Basic Wastewater Operator Practice Exam

What is the ash content remaining at the end of a VSS test equal to?

1. Inorganic solids

2. Organic solids

3. Semi-volatile organics

4. Volatile organic compounds

The correct answer is: Inorganic solids

The ash content remaining at the end of a Volatile Suspended Solids (VSS) test represents inorganic solids. In the VSS test, a sample of wastewater is subjected to heating, which causes the organic solids to combust and evaporate, leaving behind the inorganic material in the form of ash. This ash consists of non-combustible substances such as minerals, metals, and other inorganic compounds. Understanding this concept is crucial because distinguishing between organic and inorganic solids helps in assessing the composition of the wastewater and determining the efficiency of treatment processes. The presence of significant inorganic solids can affect processes such as digestion and stabilization in wastewater treatment systems. Thus, recognizing that the remainder after the VSS test signifies inorganic solids provides valuable insights into the characteristics of the wastewater being analyzed.