Table 1 Effect of hydraulic loading rate and water flow rate on the different water quality variables (Inflow and outflow) of IMTA-NFT and IMTA-FR systems in both first and second cycles.

From: Optimizing nutrient utilization, hydraulic loading rate, and feed conversion ratios through freshwater IMTA-aquaponic and hydroponic systems as an environmentally sustainable aquaculture concept

Water quality variables*

Experimental treatments

IMTA

IMTA-FRS

IMTA-NFT

Total area (m3)

40

20

122#

Qw (m3 day−1)

96

96

96

HLR (m day−1)

2.4

4.8

6.4

 

First cycle

Second cycle

First cycle

Second cycle

First cycle

Second cycle

EC (mS/cm)

 Inflow

703.38 ± 12.53

700.21 ± 10.76

706.75 ± 13.88

701.27 ± 12.11

714.63 ± 11.52

704.63 ± 14.55

 Outflow

706.63 ± 13.12

710.16 ± 11.42

703.25 ± 7.34

708.17 ± 5.67

704 ± 12.25

710.34 ± 11.45

pH

 Inflow

7.24 ± 0.11

7.28 ± 1.41

7.37 ± 1.18

7.41 ± 0.14

8.4 ± 0.33

8.44 ± 0.19

 Outflow

7.33 ± 0.42

7.37 ± 0.18

7.4 ± 4.23

7.44 ± 0.54

8.47 ± 1.11

8.51 ± 0.65

DO (mg/l)

 Inflow

5.17 ± 1.42

5.01 ± 1.21

6.11 ± 1.34

6.03 ± 1.09

6.31 ± 1.22

6.23 ± 1.01

 Outflow

6.32 ± 1.33

5.12 ± 1.03

6.44 ± 1.83

5.99 ± 1.12

7.25 ± 1.00

6.47 ± 0.90

BOD (mg/l)

 Inflow

4.64 ± 1.25

5.01 ± 1.35

3.94 ± 1.05

3.96 ± 1.37

4.52 ± 1.65

4.49 ± 0.89

 Outflow

4.41 ± 1.44

4.39 ± 1.21

3.9 ± 1.34

3.88 ± 1.09

4.67 ± 1.32

4.71 ± 0.91

COD (mg/l)

 Inflow

6.95 ± 1.34

6.92 ± 1.58

7.01 ± 1.66

7.04 ± 1.22

7.25 ± 1.12

7.22 ± 1.55

 Outflow

7.18 ± 0.95

7.15 ± 1.54

6.95 ± 0.90

6.99 ± 0.57

6.81 ± 1.92

6.78 ± 0.87

TA (mg/l)

 Inflow

277.25 ± 3.87

276.97 ± 2.23

282.94 ± 1.65

281.1 ± 2.54

274.63 ± 3.12

273.09 ± 2.75

 Outflow

280.44 ± 2.21

278.93 ± 2.67

281.63 ± 3.12

284.65 ± 4.73

273.44 ± 3.56

271.94 ± 5.12

TSS (mg/l)

 Inflow

23.73 ± 1.46

23.60 ± 1.56

14.18 ± 1.12

14.12 ± 2.23

15.1 ± 1.76

15.05 ± 3.42

 Outflow

27.74 ± 1.23

27.31 ± 1.54

22.94 ± 2.08

22.58 ± 1.56

13.92 ± 1.89

13.7 ± 1.22

NH3 (µg/l)

 Inflow

627.78 ± 5.23

618.36 ± 4.45

322.49 ± 6.44

317.65 ± 4.73

304.38 ± 6.12

299.81 ± 8.54

 Outflow

559.09 ± 9.42

552.38 ± 8.38

298.19 ± 7.11

294.91 ± 5.33

210.34 ± 7.30

209.29 ± 10.76

NO2 (µg/l)

 Inflow

42.55 ± 1.66

43.4 ± 1.08

71 ± 1.34

69.47 ± 1.33

57.4 ± 1.56

57.97 ± 1.66

 Outflow

48.73 ± 2.01

42.67 ± 1.78

57.3 ± 1.11

58.45 ± 1.45

34.15 ± 1.37

33.42 ± 1.04

NO3 (µg/l)

 Inflow

778.44 ± 1.45

774.51 ± 8.32

711.69 ± 5.45

688.92 ± 3.45

554.14 ± 7.33

559.68 ± 6.75

 Outflow

340.48 ± 3.34

370.45 ± 4.67

307.89 ± 5.11

320.21 ± 3.63

357.04 ± 5.67

345.61 ± 4.45

PO4 (µg/l)

 Inflow

51.43 ± 1.34

50.3 ± 2.26

72.08 ± 2.23

70.49 ± 1.08

78.24 ± 1.19

81.37 ± 1.28

 Outflow

67.51 ± 2.12

45.4 ± 1.80

74.25 ± 3.03

72.68 ± 1.04

74.53 ± 2.00

72.96 ± 1.54

TP (µg/l)

 Inflow

152.63 ± 3.23

148.81 ± 2.23

142.86 ± 2.34

140.72 ± 2.23

135.71 ± 3.45

149.28 ± 2.67

 Outflow

155.1 ± 3.45

140.8 ± 2.33

136.54 ± 2.93

140.15 ± 2.54

149.1 ± 3.76

147.46 ± 3.34

  1. *HLR, hydraulic loading rate = water flow rate (Qw)/total surface area of pond or hydroponic trough; Qw = 16 m3 × 6 h; EC electrical conductivity, DO dissolved oxygen, BOD biological oxygen demand, COD chemical oxygen demand, TA total alkalinity, NH3 ammonia, NO2 nitrate, NO3 nitrite, PO4 orthophosphate, TP total phosphorus; #total area by m, IMTA Integrated Multi-Trophic system, NFT Nutrient Film Technique, FRS Floating Raft Systems.
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