Chlorination terminology in water treatment: Raw water treated only with chlorine, without any preceding conventional treatment, is referred to as which type of chlorination?

Introduction / Context:
Chlorination terms are used to specify where and how chlorine is applied in the treatment train. Precise terminology helps operators and designers communicate process intent and monitor residuals.

Given Data / Assumptions:

• No coagulation, sedimentation, or filtration is performed before chlorination.
• Chlorine is the sole treatment applied to raw water prior to distribution or storage.

Concept / Approach:
Plain chlorination: chlorine is applied directly to raw water (often for small systems where raw water is already low in turbidity and contamination).Pre-chlorination: chlorine dosing prior to coagulation/sedimentation to control algae/odors.De-chlorination: removal of residual chlorine (e.g., with sulfur compounds).

Step-by-Step Solution:

Verification / Alternative check:
Review utility SOPs; small ground-water systems often employ plain chlorination when raw water meets other standards.

Why Other Options Are Wrong:
Pre-chlorination implies upstream of other steps; first-chlorination is non-standard wording; de-chlorination removes chlorine rather than applying it; breakpoint describes dose–residual behavior, not the process location.

Common Pitfalls:
Using plain chlorination on highly turbid water; inadequate contact time leading to poor disinfection.

Final Answer:
Plain chlorination