In municipal sanitation terminology, identify the incorrect statement about sewage and sewerage systems.

Introduction / Context:
Accurate use of sanitation terminology is foundational for design, regulation, and public communication. This question checks understanding of basic definitions and system comparisons.

Given Data / Assumptions:

• Sewage includes domestic, commercial, and in some cases industrial wastewater with varying dilution.
• Effluent reuse for irrigation is practiced under guidelines.
• Conservancy systems historically relied on manual collection rather than water-carriage.

Concept / Approach:
The water-carried sewerage system is globally preferred over the conservancy system due to hygiene, labor safety, odor control, and scalability. Definitions of sewage and sewerage are standardized across engineering literature.

Step-by-Step Solution:
Check (a): correct—sewage is wastewater plus carried waste products.Check (b): correct—treated effluent irrigation is practiced where standards permit.Check (c): correct—sewerage encompasses the full system and processes.Check (d): incorrect—conservancy is outdated and inferior on public-health grounds.

Verification / Alternative check:
Modern codes mandate water-carried sewerage or on-site systems meeting strict criteria; conservancy is maintained only in exceptional legacy contexts.

Why Other Options Are Wrong:

• (a), (b), and (c) are standard definitions and practices.
• (e) is wrong because (d) is demonstrably incorrect.

Common Pitfalls:
Confusing the terms sewage (the wastewater) and sewerage (the system). Also assuming all effluents are reusable without treatment—standards must be met first.

Final Answer:
The old conservancy system was definitely better than the water-carried sewerage system.