Tennessee Wastewater Operator Practice Exam

What test method should be used to determine the concentration of organic solids in a digester if the estimated TS concentration is 5%?

1. Total Suspended Solids

2. Total Volatile Solids

3. Biochemical Oxygen Demand

4. Chemical Oxygen Demand

The correct answer is: Total Volatile Solids

The appropriate test method to determine the concentration of organic solids in a digester, especially when the total solids (TS) concentration is estimated to be 5%, is Total Volatile Solids (TVS). Total Volatile Solids specifically measure the organic portion of the solid waste, which is crucial in evaluating the effectiveness of the digestion process. In anaerobic digestion, for example, it is the organic solids that are broken down by microorganisms, producing biogas and leaving behind inert materials. By assessing the TVS, operators can gain insight into how much organic material is potentially available for degradation. In contrast, Total Suspended Solids (TSS) would provide a measure of all suspended solids, both organic and inorganic, making it less suitable for specifically determining organic content. Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) are important parameters that assess the biodegradability and oxidizable material but do not specifically quantify the amount of organic solids in a digester. Hence, Total Volatile Solids is the best choice for this scenario, allowing operators to focus on the organic constituents critical for digestion processes.