Biological nutrient recovery from culturing of pearl gourami ( Trichogaster leerii ) by cherry tomato ( Solanum lycopersicum ) in aquaponic system

Abstract

The possibility of using different densities of cherry tomato as a bio-filter in a simple media-based aquaponic system to recycle nutrients from pearl gourami intensive culture wastewater was evaluated. Water quality parameters including total ammonia nitrogen (TAN), nitrite (NO₂⁻), nitrate (NO₃⁻), phosphate (PO₄³⁻), pH, and dissolved oxygen (DO) were determined in outlet of the aquaponic system during a 60-day experimental period. Cherry tomato was planted at four densities of 0 (control), 3 (T1), 6 (T2), and 9 (T3) plants per aquaponic unit with a constant fish stock density. Each treatment was equipped with aquaponic systems containing fish tank and plant growing bed. Productivity of the system was measured by recording the fish and plant growth indices. The potential in removing nitrogen of the water was the highest in T3 (with nine plants) compared to other treatments (p < 0.05). The highest concentrations of TAN (6.59 ± 0.241 mg/L), nitrite (0.42 ± 0.005 mg/L), nitrate (0.45 ± 0.162 mg/L), and phosphate (30.47 ± 0.371 mg/L) were obtained in control group, while the lowest concentrations of TAN (0.05 ± 0.091 mg/L), NO₂⁻ (0.11 ± 0.008 mg/L), NO₃⁻ (29.77 ± 0.205 mg/L), and phosphate (18.59 ± 0.185 mg/L) were detected in T3 (p < 0.05). The maximum fish weight gain was recorded in T3 (26 ± 0.014%) with 1.26 ± 0.059 FCR, and the lowest fish weight gain was measured in the control group (15 ± 0.024%) with 2.19 ± 0.446 FCR (p < 0.05). Total plant length gain was reached at the maximum value in T3 (74.70 ± 1.153 cm) in comparison to other groups (p < 0.05). It was concluded that small-scale aquaponic growing bed system can be created a sustainable ecosystem which both the plant and fish can thrive and suitable for home-made production system.

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