Water Quality Parameters MCQ with answer and solution

Concept

Water Quality Parameters and Treatment Procedures

Formula

N/A

Step-by-step solution

1. Compare given parameters against standard limits: Fluoride (2.5 mg/L), Total Hardness (300 mg/L), and Iron (3.0 mg/L) exceed permissible limits. 2. Note that an MPN of 50 per 100 mL indicates the presence of bacteria, necessitating disinfection. 3. Conclude that treatment must remove fluorides, hardness, and iron followed by disinfection.

Explanation

The test results show that fluorides (2.5 mg/L), total hardness (300 mg/L), and iron (3.0 mg/L) all exceed safe drinking water limits, while the presence of bacteria (MPN of 50 per 100 mL) requires disinfection. Since turbidity and pH are within acceptable limits, the water specifically needs treatment to remove fluorides, hardness, and iron, followed by disinfection to eliminate pathogens.

Shortcut

To remember standard water quality limits and treatment needs, use the mnemonic "F-H-I-M (Fix High Impurities)": - Fluoride > 1.5 mg/L, Hardness > 200 mg/L, Iron > 0.3 mg/L: All exceed permissible limits and require specific removal. - MPN > 0: Any bacterial presence requires Disinfection. - Turbidity (≤ 5 NTU) & pH (6.5-8.5): Within safe limits, no extra treatment needed.

Common mistake

A common mistake is selecting incomplete options like B or C by only checking one or two parameters instead of evaluating all given values against standard drinking water limits. Another frequent error is selecting option A by incorrectly assuming turbidity needs treatment, whereas turbidity (5 mg/L) and pH (7.4) are within acceptable limits, but fluorides, hardness, iron, and bacterial count (MPN) all require treatment.