Dechlorination of Highly Chlorinated Water - Disinfection of Pipelines and Storage Facilities Field Guide - page 102

Dechlorination Fixed Volume Chemical Calculator

(c7-1) 1 2 3 4

Total
amount
of
chemical
needed

Volume of
water to be
dechlorinated
(from Tables
3-6 and 5-2,
and calculators
c5-1, 5-2, 5-3,
and 5-4)

Amount
of
chemical
(from
Table 7-5)

Chlorine
residual,
mg/L

Volume
(from
Table 7-5,
either
100,000
gal or
100 m 3 )

=

× × ÷

This calculator is used for calculating the amount of dechlori-
nation chemical for a fixed volume and it has four factors. Insert
the values for each factor and calculate the amount of chemical
needed for this procedure.
￿ The first factor is the total volume of water to be dechlo-

rinated. This is the volume of the pipeline, slug, or storage
tank chlorination water. The amount is obtained from
the applicable table (3-6, 5-2) or calculator (c5-1, 2, 3, 4).

￿ The second factor is the amount of chemical from Table 7-5.

￿ Next is the chlorine residual in mg/L.

￿ Last is the volume in Table 7-5 (either 100,000 gallons or

100 cubic meters).

Example 1. Calculate the amount of sodium sulfite needed
to dechlorinate a chlorine concentration of 10 mg/L in a vertical
cylindrical tank that is 20 ft in diameter and is 35 ft maximum
depth.
1. Using calculator c5-4: 5.87 × 20 × 20 × 35 = 82,180 gal

2. 1.63 lb
3. 10 mg/L
4. 100,000 gal
82,180 × 1.63 × 10 ÷ 100,000 = 13.43 lb of sodium sulfite

Ops Tip Insert values in calculator c7-1 above