Table 4.
Seasonal changes in growth rates of azolla, nutrient removals and chlorophyll concentration in synthetic wastewater
| Months | Days from start | Growth density, g dw/m2 | Growth rate, g dw/m2-day | NH4-N initial, mg/l | NH4-N final, mg/l | NH4-N uptake rate, mg/l-day | PO4-P initial, mg/l | PO4-P final, mg/L | PO4-P uptake rate, mg/l-day | N/P uptake | Chl A + B, μg/ml |
|---|---|---|---|---|---|---|---|---|---|---|---|
|
January |
10 |
NA |
NA |
40.0 |
16 ± 6 |
2.4 ± 0.8 |
20.0 |
13.2 ± 4 |
0.68 ± 0.4 |
3.5 |
33.7 ± 10 |
| 15 |
NA |
NA |
|
6.1 ± 3 |
2.3 ± 0.7 |
|
4.1 ± 2 |
1.06 ± 0.5 |
2.1 |
12.3 ± 8 |
|
| 20 |
58.2 ± 8 |
2.9 ± 0.9 |
|
0.0 |
2.0 ± 0.9 |
|
0.0 |
1.0 ± 0.6 |
2 |
2.3 ± 0.5 |
|
|
April |
10 |
NA |
NA |
40.0 |
18.7 ± 8 |
2.1 ± 1.0 |
20.0 |
13.6 ± 4 |
0.64 ± 0.3 |
3.3 |
12.8 ± 4.8 |
| 15 |
NA |
NA |
|
4.5 ± 2 |
2.4 ± 0.7 |
|
8.5 ± 1 |
0.76 ± 0.3 |
3.1 |
0.5 ± 0.2 |
|
| 20 |
88.5 ± 18 |
4.4 ± 0.7 |
|
2.5 ± 1.1 |
1.9 ± 0.9 |
|
0.0 |
1.0 ± 0.6 |
1.9 |
0.0 |
|
| June | 10 |
NA |
NA |
40.0 |
23.1 ± 6 |
1.7 ± 1.0 |
20.0 |
16.9 ± 5 |
0.31 ± 0.1 |
5.5 |
8.8 ± 1.8 |
| 15 |
NA |
NA |
|
10.1 ± 4 |
2.0 ± 1.1 |
|
10.1 ± 5 |
0.7 ± 0.2 |
3 |
3.9 ± 1.2 |
|
| 20 | 67.2 ± 6 | 3.3 ± 0.9 | 8.1 ± 3 | 1.5 ± 0.8 | 6.1 ± 3 | 0.7 ± 0.3 | 2.3 | 2.7 ± 1.2 |
N, nitrogen; P, phosphorus; NA (not analyzed).