In 1000 kg of typical domestic sewage, how much matter is present in suspension and in solution? Identify the correct combination based on standard composition ranges used in sanitation design.

Introduction / Context:
Understanding typical concentrations of suspended and dissolved solids in sewage is essential for sizing screens, grit chambers, primary sedimentation, and biological treatment. Textbook values provide reasonable design estimates when site-specific data are not yet available.

Given Data / Assumptions:

• Total mass of sewage considered: 1000 kg.
• Representative domestic sewage (no unusual industrial inputs).
• We are comparing given standard figures for suspended and dissolved fractions.

Concept / Approach:
Standard references commonly cite order-of-magnitude values for typical sewage: a small fraction is present as suspended solids (settleable and non-settleable), and another fraction as dissolved solids. Among the given options, 0.112 kg in suspension together with 0.225 kg in solution is the pair that matches widely taught benchmark values for preliminary design exercises.

Step-by-Step Solution:
1) Interpret the options: individual masses in suspension or solution versus a combined statement.2) Compare with standard indicative values used in many MCQs and handbooks (suspended ≈ 0.112 kg/1000 kg; dissolved ≈ 0.225 kg/1000 kg).3) Select the option that includes both correct figures: the combined statement.

Verification / Alternative check:
These numbers are consistent with the notion that total solids in domestic sewage typically fall well below 1% by mass, validating that suspended and dissolved portions are of the order of a few hundred grams per 1000 kg.

Why Other Options Are Wrong:

• 0.112 kg in solution: Misplaces the value; 0.112 kg is cited for suspended solids.
• 0.450 kg in suspension: Exaggerated for typical domestic sewage; would imply unusually high SS.
• Single-value options omit the dissolved fraction that is commonly cited together.

Common Pitfalls:
Assuming the suspended fraction dominates total solids; in domestic sewage, dissolved and colloidal fractions are significant.

Final Answer:
both 0.112 kg in suspension and 0.225 kg in solution