In raw sewage, the solid content is closest to:

In raw sewage, the solid content is closest to:

• A. 0.1% solids
• B. 5% solids
• C. 20% solids
• D. 50% solids

Answer: (A)

Raw sewage is mostly water; the solid material makes up only a tiny fraction of the total mass. In typical influent, solids are about one-tenth of a percent by weight, which translates to roughly one gram of solids per liter of wastewater. That’s why the closest value is 0.1% solids. The other options imply far more solids than raw wastewater normally contains—5%, 20%, or 50% would be thick sludges, not ordinary influent.

Raw sewage is mostly water; the solid material makes up only a tiny fraction of the total mass. In typical influent, solids are about one-tenth of a percent by weight, which translates to roughly one gram of solids per liter of wastewater. That’s why the closest value is 0.1% solids. The other options imply far more solids than raw wastewater normally contains—5%, 20%, or 50% would be thick sludges, not ordinary influent.