South Dakota Administrative Rules › Title 74 - Department of Environment And Natural Resources › Article 74:02 - Water rights › Chapter 74:02:04 - Well construction standards › Appendix H - Recommended procedure for chlorine disinfection of water wells

Current through Register Vol. 51, page 10, July 15, 2024
(See §
									74:02:04:58.01)
RECOMMENDED PROCEDURE FOR CHLORINE DISINFECTION OF WATER WELLS *
Introduction
A water well should be thoroughly cleaned and disinfected with a strong
	 chlorine solution after:
1. ORIGINAL CONSTRUCTION
4. A PERIOD OF NONUSE
2. ANY REPAIR OR MAINTENANCE
5. TWO OR MORE "UNSAFE" WATER
3. FLOODING
BATERIOLOGICAL SAMPLES
ARE TRACED TO THE WELL
Adequate chlorine requires a certain chlorine dosage for a minimum
	 contact time - 100 parts per million for 2 hours, 50 parts per million for 8
	 hours, or 25 parts per million for 24 hours.
Chlorine for disinfection of water wells can be either 5.25% sodium
	 hypochlorite solution of 65% calcium hypochlorite powder. A 5.25% hypochlorite
	 solution is common household chlorine bleach such as "Hilex," "Chlorox," or
	 "Purex" available at grocery stores and supermarkets. The 65% calcium
	 hypochlorite powder is available from chemical supply houses and is known
	 commercially as "HTH," "Perchloron," or "Pittchlor."
Recommended Procedure
1 Determine the chlorine dosage for the
  desired contact time from the following tables:
AMOUNT OF CHLORINE NECESSARY PER 10 FEET OF WATER IN
	 WELL
5.25% Sodium Hypochlorite (Bleach)
Inside Diameter
of Well
100 ppm*
50 ppm*
25 ppm*
Casing
for 2 hrs
for 8 hrs
for 24 hrs
1 1/4 inches
1/8 fl.oz.
----------
----------
2 inches
1/2 fl.oz.
1/4 fl.oz.
1/8 fl.oz.
3 inches
1 fl.oz.
1/2 fl.oz.
1/4 fl.oz.
4 inches
1 1/2 fl.oz.
3/4 fl.oz.
3/8 fl.oz.
6 inches
4 fl.oz.
2 fl.oz.
1 fl.oz.
8 inches
7 fl.oz.
3 1/2 fl.oz.
1 3/4 fl.oz.
10 inches
10 fl.oz.
5 fl.oz.
2 fl.oz.
12 inches
2 cups
1 cup
1/2 cup
18 inches
4 1/2 cups
2 1/4 cups
1 1/8 cups
24 inches
7 1/2 cups
3 3/4 cups
1 7/8 cups
36 inches
17 1/2 cups
8 3/4 cups
4 3/8 cups
65% Calcium Hypochlorite
100 ppm*
50 ppm*
25 ppm*
for 2 hrs
for 8 hrs
for 24 hrs
-----------
-----------
-----------
-----------
-----------
-----------
-----------
-----------
-----------
-----------
-----------
-----------
1/4 oz.
1/8 oz.
1/16 oz.
1/2 oz.
1/4 oz.
1/8 oz.
3/4 oz.
3/8 oz.
1/16 oz.
1 oz.
1/2 oz.
1/4 oz.
1 1/2 oz.
1 1/4 oz.
5/7 oz.
4 1/2 oz.
2 1/4 oz.
1 1/8 oz.
10 oz.
5 oz.
1 1/2 oz.
* ppm = parts per million
1 heaping tablespoon of 65%
8 fluid ounces = 1 cup
chlorine powder = 1/2 oz
2. Prepare a
  chlorine solution, lift well pump, and pour the chlorine solution into the
  well.
3. Lower the pump and operate
  until a chlorine odor is noticed at all discharge points.
4. Leave the chlorine and water solution in
  the well for the recommended contact time.
Donot
use the
  water.
5. At the end of the contact
  time, pump the well to waste until the chlorine odor cannot be detected. DO NOT
  ALLOW CHLORINATED WATER TO ENTER A RIVER, LAKE, OR STREAM.
6. Pump the well for a considerable period of
  time, collect a bacteriological water sample, and submit it for
  testing.
AWWA A 100-90, "AWWA Standard for Water Wells," January 29, 1990.
		Published by American Water Works Association, 666 West Quincy, Denver, CO
		80235