Advanced Nutrient Removal & Resource Recoverymedium
The 'volatile suspended solids' (VSS) to 'total suspended solids' (TSS) ratio in activated sludge is typically:
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Correct Answer
0.7–0.85, reflecting the predominantly organic nature of biological sludge with some inorganic content from influent TSS and chemical addition
VSS/TSS ratio of 0.7–0.85 is typical for activated sludge: VSS represents the active biological fraction (bacteria, protozoa) plus non-volatile organics; TSS includes VSS plus inorganic solids (from influent, chemical precipitation). Ratio decreases with chemical P removal (adds inorganic solids) or high inorganic influent TSS.
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