Agriculture Reference
In-Depth Information
TABLE 3
Injection rate of chlorine in gallons per hour.
Gallons of chlorine (5.25% solution) per hour
Desired
chlorine
level in
ppm
Irrigation Water Flow Rate, gallons per minute (GPM)
100
150
200
250
300
350
400
450
500
1
0.114
0.171
0.229
0.286
0.343
0.400
0.457
0.514
0.571
2
0.229
0.343
0.457
0.571
0.686
0.800
0.914
1.029
1.143
5
0.571
0.857
1.143
1.429
1.714
2.000
2.286
2.571
2.857
10
1.143
1.714
2.286
2.857
3.429
4.000
4.571
5.143
5.714
15
1.714
2.571
3.429
4.286
5.143
6.000
6.857
7.714
8.571
20
2.286
3.429
4.571
5.714
6.857
8.000
9.143
10.29
11.43
25
2.857
4.286
5.714
7.143
8.571
10.00
11.43
12.89
14.29
30
3.429
5.143
6.857
8.571
10.29
12.00
13.71
15.43
17.14
50
5.714
8.571
11.43
14.29
17.14
20.00
22.86
25.71
28.57
Gallons of chlorine (10% solution) per hour
Desired
chlorine
level in
ppm
Irrigation Water Flow Rate, gallons per minute (GPM)
100
150
200
250
300
350
400
450
500
1
0.060
0.090
0.120
0.150
0.180
0.210
0.240
0.270
0.300
2
0.120
0.180
0.240
0.300
0.360
0.420
0.480
0.540
0.600
5
0.300
0.450
0.600
0.750
0.900
1.050
1.200
1.350
1.500
10
0.600
0.900
1.200
1.500
1.800
2.100
2.400
2.700
3.000
15
0.900
1.350
1.800
2.250
2.700
3.150
3.600
4.050
4.500
20
1.200
1.800
2.400
3.000
3.600
4.200
4.800
5.400
6.000
25
1.500
2.250
3.000
3.750
4.500
5.250
6.000
6.750
7.500
30
1.800
2.700
3.600
4.500
5.400
6.300
7.200
8.100
9.000
50
3.000
4.500
6.000
7.500
9.000
10.50
12.00
13.50
15.00
7.2.5 INJECTING ACID
Acids are injected into irrigation water to treat plugging caused by calcium carbonate
(lime) and magnesium precipitation. Water with a pH of 7.5 or higher and a bicarbon-
ate level higher than 100 ppm poses a risk of mineral precipitation, depending on the
hardness of the water. Hardness of water, determined by the concentrations of calcium
and magnesium, is classified as follows: soft (0 to 60 ppm of Ca and Mg); moderate
(61 to120); hard (121 to180); very hard (more than 180 ppm). Moderate, hard and very
hard water warrant acid injection.
Sulfuric, phosphoric, urea-sulfuric, or citric acid can be used. The type most com-
monly used in drip irrigation is 98% sulfuric acid. Acetic acid, or vinegar, can be used
in organic farming, although it is much more expensive. If the irrigation water has
more than 50 ppm of calcium, phosphoric acid should not be injected, unless the injec-
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