Sanitation terminology clarification: “Sullage” (wastewater excluding human excreta) does NOT include wastewater from which household source?

Introduction / Context:
Sanitation engineering distinguishes between blackwater (containing human excreta) and greywater (also called sullage) that originates from non-toilet fixtures. Proper classification influences system design, treatment requirements, and reuse options.

Given Data / Assumptions:

• Household wastewater streams considered: wash basins, bathrooms, kitchen sinks, laundry, and toilets.
• Terminology: “sullage” or greywater excludes human excreta.

Concept / Approach:
Greywater/sullage is typically lower in pathogens and organics than blackwater and may be treated and reused more readily. Toilet wastewater (blackwater) contains fecal matter and urine and demands higher treatment standards.

Step-by-Step Solution:
1) Define sullage: wastewater from non-toilet uses (baths, basins, kitchens, laundry).2) Identify the source that contains human excreta: toilets.3) Therefore, sullage does not include toilet wastewater.

Verification / Alternative check:
Design codes and decentralized wastewater guidelines consistently classify toilet discharge as blackwater, separate from sullage/greywater streams.

Why Other Options Are Wrong:
Wash basins, bathrooms, kitchens, laundry: All produce greywater; contaminants include soap, oils, and food particles but no fecal matter by design.

Common Pitfalls:

• Confusing the terms “sludge” (settled solids in treatment units) and “sullage” (greywater).
• Assuming kitchen wastewater is blackwater; it is greywater but often grease-rich.

Final Answer:
Toilets