Disinfection of Pipelines - Disinfection of Pipelines and Storage Facilities Field Guide - page 39

❑ Valves, hydrants, tees, and other appurtenances.

No valves or hydrants are listed.

❑ Volume of chlorination water to disinfect pipeline.

The tablet method does not use chlorinated water to
fill the line. The pipeline volume from Table 3-6 is
31.40 L/m 1,000 m = 31,400 L. Fill the pipeline no more

than 1 ft/sec fill rate. For 200-mm pipe that is 9.4 L/s.
At that rate it will take 31,400/9.4 = 3,340 sec or
56 min to fill the line.

×

❑ Amount of chlorine needed to complete the disinfection

procedure.
From Table 3-7b, one 250-mL measure of calcium
hypochlorite granules is needed for each 152-m length
of 200-mm pipe length. Therefore, 1,000÷152 = 6.6. So,
about seven 250-mL measures (1,750 mL) of calcium
hypochlorite granules are needed. Place one 250-mL
measure of granules about every 150 m.

Continuous-Feed Method
In this method water from the distribution system flows
slowly into the new pipe section while a concentrated chlorine
solution is added. Chlorine solution is injected using a solution-
feed chlorinator or pumped from a concentrated hypochlorite
solution (Figure 3-13). This method is acceptable for general
application.
Use Tables 3-9a & b to determine the amount of chemical
needed to achieve 25 mg/L dosage using the continuous-feed
method. When using liquid chlorine from a cylinder, the amounts
shown in Table 3-9a are used. The amount for 100 ft and 500 ft of
pipeline are listed in the table and the weights are both in
pounds and grams. Sodium hypochlorite solution amounts are
shown in Table 3-9b. The amount (in both gallons and liters) for
100-ft and 500-ft pipeline lengths and 1% and 5% solution
strengths are given.