1. Iron and Aluminum Compounds for Removing Phosphorus and Turbidity from Pond Waters
Claude E. Boyd, Puan Pengseng and Suthira Soongsawang Department of Fisheries and Allied Aquacultures Auburn University, Alabama USA

2. Turbidity Removal _ Soil colloids + Al3+(Fe3+)  _ Soil colloids
The neutral particles will flocculate and settle from the water.
Al Al3+
   
   
   
   
Al3+

3. Phosphorus Removal AL3+ + H2PO4- + 2H2O  AlPO42H2O + 2H+
Fe3+ + H2PO4- + 2H2O FePO42H2O + 2H+

4. Effect on Total Alkalinity
Al3+ + 3H2O = Al(OH)3 + 3H+
CaCO3 + 2H+ = CO2 + H2O + Ca2+
1 mg/L Al3+ = 5.6 mg/L CaCO3
Same reaction for iron, but
1 mg/L Fe3+ = 2.7 mg/L CaCO3

5. Kemira products for removing phosphorus and suspended solids from aquaculture pond water.
Product name
Specific gravity
(g/cm3)
Ferric chloride, liquid, 11.1% Fe
1.38
Ferix-3, granular ferric sulfate, 21% Fe
N/A
Aluminum chloride, liquid, 5.6% Al
1.27
Ferrous chloride, 25% solution
1.24
Ferric chloride, liquid, 13.5% Fe
1.43
Ferric sulfate, 13.5% Fe solution
1.55

6. Kemira products for removing phosphorus and suspended solids from aquaculture pond water.
Product name
Specific gravity
(g/cm3)
PAX-18, liquid polyaluminum chloride, 9% Al
1.37
Aluminum sulfate (alum) solution, liquid,
% Al (?)
1.33
Ferrous sulfate, 5-7% Fe solution
1.15
Clear PASS 1000, liquid, 13% Fe
1.27
Polyferric sulfate, 12% Fe solution
1.5

7. Effect of Kemira products at 10 mg/L on total phosphorus concentration and turbidity in laboratory tests.
TP (mg/L)
Turbidity (NTU)
Product
Control
Treated
Ferric chloride, 11.1% Fe
0.30
0.03 23
1.6
Ferric chloride, 13.5% Fe 25
2.4
Granular ferric sulfate,
21% Fe
0.29
0.24 24 20
Ferric sulfate, 13.5% Fe
0.34
0.05 22
4.0
Polyferric sulfate, 12% Fe
0.40
0.23 17 12
Ferrous chloride, 25% Fe
0.33
0.25 28 30

8. Effect of Kemira products at 10 mg/L on total phosphorus concentration and turbidity in laboratory tests.
TP (mg/L)
Turbidity (NTU)
Product
Control
Treated
Ferrous sulfate, 5-7% Fe
0.30
0.26 12 10
Clear PASS 1000, liquid,
13% Fe
0.25 19 17
Aluminum chloride, 5.6% Al
0.32
0.03
1.4
Aluminum sulfate, % Al (?)
Polyaluminum chloride,
9% Al
0.29
0.22 15

9. Product concentration (mg/L) Total alkalinity (mg/L)
Effects of liquid ferric chloride (13.5% Fe) on water quality in laboratory tests.
Product concentration (mg/L)
SRP
(g/L) TP
(mg/L)
Turbidity (NTU) pH
Total alkalinity (mg/L)
208
0.35
10.1
7.6
80.1 2 75
--- 4 8 6 9
0.08
2.2
7.1
58.7
0.07
1.6
7.0
52.1 10
0.05
1.0
6.8
44.1

10. Product concentration (mg/L) Total alkalinity (mg/L)
Effects of liquid ferric sulfate (13.5% Fe) on water quality in laboratory tests.
Product concentration (mg/L)
SRP
(g/L) TP
(mg/L)
Turbidity (NTU) pH
Total alkalinity (mg/L)
183
0.33
6.9
7.5
81.4 2 12
--- 4 17 6 8
0.12
3.2
7.2
60.1 9
0.09
2.2
7.0
54.7 10
0.06
1.6
6.8
47.4

11. Days after application
Average concentrations of soluble reactive phosphorus (mg/L) in control ponds and in ponds treated at 10 mg/L with ferric chloride and ferric sulfate.
Before
Days after application
Treatment
application 1 7 14
Ferric chloride
0.011
0.005
0.009
0.010
Ferric sulfate
0.006
0.012
Control
0.018
0.014

12. Days after application
Average concentrations of total phosphorus (mg/L) in control ponds and in ponds treated at 10 mg/L with ferric chloride and ferric sulfate.
Before
Days after application
Treatment
application 1 7 14
Ferric chloride
0.09
0.03
0.04
Ferric sulfate
0.11
0.05
Control
0.13
0.12
0.06

13. Days after application
Average concentrations of turbidity (NTU) in control ponds and in ponds treated at 10 mg/L with ferric chloride and ferric sulfate.
Before
Days after application
Treatment
application 1 7 14
Ferric chloride
218
189
219
243
Ferric sulfate
143
127
155
162
Control
200
228
238
214

14. Days after application Total alkalinity (mg/L)
Average concentrations of water quality variables in control ponds and in ponds treated at 10 mg/L with ferric chloride and ferric sulfate (continued).
Before
Days after application
Treatment
application 1 7 14
Total alkalinity (mg/L)
Ferric chloride
33.7
30.7
30.6
32.3
Ferric sulfate
29.2
29.1
28.1
Control
35.2
33.3
38.9
33.1 pH
7.8
7.9

15. Average fish survival and production in ponds treated eight times during the production period with 10 mg/L of ferric chloride and ferric sulfate. Treatments and control were replicated three times.
Variable
Ferric chloride
Ferric sulfate
Control
Survival (%)
Channel catfish
76.5
81.1
80.7
Grass carp
100 95 92
Production (kg/ha)
4,572
4,867
4,551
264
328
401