Dechlorination of Highly Chlorinated Water - Disinfection of Pipelines and Storage Facilities Field Guide - page 103

Op s T ip Insert values in calculator c7-1 above

Example 2. Calculate the amount of ascorbic acid needed
to dechlorinate the water from 500 m of a 200-mm diameter
pipeline filled with 25 mg/L chlorine solution.
1. Using Table 3-6: 31.4 L/m

500 m = 15,700 L or 15.7 m 3 ×

2. 0.25 kg
3. 25 mg/L
4. 100 gal
15.7 × 0.25 × 25 ÷ 100 = 0.98 kg of ascorbic acid

Dechlorination Continuous Solution Feed Chemical
Calculator
A 1% solution of any of the dechlorination chemicals listed in
Table 7-2 (assuming 100% strength solid to start) is prepared by:
1. Mixing 0.083 lb of solid with each gallon of water
2. Mixing 1.3 oz of solid with each gallon of water
3. Mixing 10 g of solid with each liter of water
4. Mixing 10 kg of solid with each cubic meter of water

(c7-2)

Dechlori-
nation
chemical
feed rate
(gph)

Chlorinated
water flow
rate (gpm)
(withdrawal
or fill)

Chlorine
residual
(mg/L)

Dechlori-
nation
chemical
dosage
(Table 7-2)

Strength of
dechlori-
nation
chemical
solution (%)

= 0.006 × × × ÷

(c7-3)

Dechlori-
nation
chemical
feed rate
(mL/min)

Chlorinated
water flow
rate (gpm)
(withdrawal
or fill)

Chlorine
residual
(mg/L)

Dechlori-
nation
chemical
dosage
(Table 7-2)

Strength of
dechlori-
nation
chemical
solution (%)

= 0.038 × × ×

÷