Typical total solids in domestic sewage: Approximately how many kilograms of total solids are present in 1000 kg of typical domestic sewage?

Introduction / Context:
Total solids (TS) in domestic sewage are a key indicator for process design and loading of primary settling and biological treatment units. Knowing the approximate fraction of solids helps estimate sludge production and clarifier performance.

Given Data / Assumptions:

• Typical municipal sewage (mainly domestic) without undue industrial loads.
• Representative TS concentration around 1000–2000 mg/L (0.1–0.2% by mass).
• 1000 kg of sewage is roughly 1000 L for estimation because the density is close to water.

Concept / Approach:
Domestic sewage often contains about 0.1% by weight of solids, sometimes up to 0.2% depending on local conditions. Converting this mass fraction to kilograms per 1000 kg gives an easy estimate of total solids present.

Step-by-Step Solution:
Assume TS mass fraction ≈ 0.1–0.2%.Compute solids in 1000 kg: 0.001–0.002 of 1000 kg = 1.0–2.0 kg.Hence the best approximate range is 1.0 to 2.0 kg.

Verification / Alternative check:
Standard texts report TS ≈ 500–1200 mg/L (volatile + fixed) for domestic sewage; many systems see near 1000 mg/L, supporting ~1 kg per 1000 kg, and up to ~2 kg where stronger wastewater occurs.

Why Other Options Are Wrong:
0.5–1.0 kg: can be low for typical domestic sewage.5.0–10.0 kg: implies 0.5–1.0% solids, which is far higher than usual domestic sewage.15–20 kg: much too high for typical cases.

Common Pitfalls:

• Confusing total solids with suspended solids only.
• Using industrial-strength wastewater values for domestic sewers.

Final Answer:
1.0 to 2.0 kg