Why is the pure chlorine quantity divided by 0.30 to get the bleaching powder quantity?

Bleaching powder contains only 30% available chlorine, so more powder is needed

30% of the powder is lost during mixing

Bleaching powder is 30% stronger than chlorine gas

Only 30% of the flow is disinfected

2079 Bhadra · 4 marks

Bleaching powder for 2 MLD, 30% chlorine

Short answer

For2 MLD flow and0.5 mg/L chlorine dose with30% available chlorine, chlorine need=1.00 kg/day, so bleaching powder required=3.33 kg/day.

Calculate the quantity of bleaching powder required to be added in the treatment plant to disinfect 2 MLD of water if the dose of chlorine is 0.5 ppm and 30% chlorine is available in bleaching powder.

Flow = 2 MLD $= 2\times10^6$ l/day; chlorine dose = 0.5 ppm $=0.5$ mg/l; available chlorine in bleaching powder = 30 %.

\begin{aligned} \text{Chlorine required} &= 0.5\ \text{mg/l}\times 2\times10^6\ \text{l/day} = 10^6\ \text{mg/day} = 1.00\ \text{kg/day} \\ \text{Bleaching powder} &= \frac{1.00}{0.30} = 3.33\ \text{kg/day} \end{aligned}

Answer: 3.33 kg of bleaching powder per day.

✓ Answer checked by Claude Opus 5.5 (high effort)

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