Controlling algal growth in water systems: Which operational treatment is most commonly applied to suppress algae proliferation in reservoirs and distribution networks?

Introduction / Context:
Excessive algal growth in raw water sources and storage can cause taste and odour problems, filter clogging, and downstream disinfection challenges. Operators employ chemical and process controls to limit algal blooms and maintain water quality. This question seeks the commonly used operational measure to directly suppress algae.

Given Data / Assumptions:

• The target is operational suppression, not long-term watershed nutrient control.
• Options reflect common water treatment steps.
• The context is potable water treatment and storage.

Concept / Approach:
Chlorination, via free chlorine or chlorinated compounds, serves both as a disinfectant and an algicide at appropriate doses. It damages cell membranes and disrupts metabolic pathways in algae. While aeration can mitigate stratification and reduce odours, it does not reliably kill algae. “Bleaching” is a vague term; in water treatment, sodium hypochlorite (a bleach) is essentially chlorination. Deoxidation is not a standard algal control step and could even favour anaerobic conditions that create other problems.

Step-by-Step Solution:
Identify the option that directly inactivates algal cells: chlorination.Check practicality and prevalence in utilities: widely used with residual control.Confirm other options are either imprecise or non-germane to direct control.

Verification / Alternative check:
Operational manuals recommend pre-chlorination for algae-laden waters and periodic chlorination of tanks to prevent regrowth, consistent with industry practice.

Why Other Options Are Wrong:
Deoxidation: Not a standard control; may worsen tastes due to anaerobic by-products.Bleaching: Non-technical phrasing; when used, it is simply chlorination.Aeration: Helpful for odour and mixing but not a dependable algicide.

Common Pitfalls:

• Confusing general “bleach” with precise chlorination dosing and contact time.
• Over-chlorination causing disinfection by-product formation; dose optimization is essential.

Final Answer:
chlorination