In wastewater analysis, which term encompasses the combined amount of solids that are suspended, settleable, and dissolved?

• A. Suspended Solids
• B. Settleable Solids
• C. Total Solids
• D. Dissolved Solids

Answer: (C)

In wastewater analysis, solids exist as dissolved material and as particulate matter, some of which may settle out. Total Solids is the term that includes every solid present in the sample—both dissolved and all particulate forms, including what would settle under gravity. In practice, TS equals the dissolved solids plus the suspended solids (TS = TDS + TSS), with settleable solids being part of the suspended fraction. The other terms describe only specific portions: dissolved solids are those dissolved in the water; suspended solids are the solids remaining in suspension; settleable solids are the part that settles. Therefore, Total Solids best represents the combined amount of solids that are suspended, settleable, and dissolved.