This paper presents data obtained through trials on small-scale aquaponics subsystem which performs the roles of biological and mechanical filters for aquaculture water quality remediation. Aquaponics is a bio-integrated food production system, consisting of closed recirculating aquaculture combined with hydroponics. The trials were conducted on Nile tilapia (Oreochromis niloticus), and green beans (Phaseolus vulgaris) and the Chinese cabbage (Brassica rapa chinensis) over a period of 70 days. The results revealed that the system is more efficient in terms of plant growth and does not adversely affect the growth of captive stock of fish. Mean (± S.D.) values of water temperature, DO, pH, NH3-N, NO2-N, NO3-N and PO4-P during the trial were 25.

Aim of study: To evaluate the biomass production of green bean (Phaseolus vulgaris) in a media-filled aquaponics system together with Genetically Improved Farmed Tilapia, GIFT (Oreochromis niloticus).Area of study: Kota Kinabalu, Sabah (Malaysia).Material and methods: The experiment involved modulating and optimizing the density of extractive species (plants) in the hydroponic tank (55 cm × 35 cm). Five treatments were carried out: T0 (control-without plant), T2 (2 plants), T4 (4 plants), T8 (8 plants), T12 (12 plants) where the stocking density of GIFT was 30 tails (identical in all the treatments). Water volume in each treatment was 800 L and the experimental set up was closed recirculating type. The trials were carried out over a period of 90 days.Main results: Growth of the GIFT was not affected by the presence of green bean or by manipulation of the stocking density. Treatment T4 yielded significantly higher biomass production of green beans (1556.4 ± 88.9 g), compared to T2 (1083.6 ± 86.9 g), T8 (404.6 ± 47.9 g), and T12 (401.8 ± 98.1 g). There were noticeable fluctuations in the concentrations of NH3-N (ammonia), NO2-N (nitrite), NO3-N (nitrate) and PO4-P (phosphate) over the experimental period that indicated the process of nitrification and absorption of nutrients.Research highlights: The nitrogenous waste produced by the fish supported the biomass of the green beans in the aquaponics system and the waste uptake of this extractive species is effective enough for reuse of the water for rearing of GIFT.

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Aquaponics is rapidly emerging as a sustainable aquatic food production system that addresses the many concerns associated with aquaculture, especially those related to environmental footprint. Depending on certain factors aquaponics can be graded as low-carbon, carbon neutral or carbon negative method. In aquaponics, water discharged from the fish production chamber feeds the plants and plants absorb the waste and filter the water which returns to the fish tank. This characterizes the circular bioeconomy of the system. Nitrifying bacteria play a vital role in biological filtration by way of transforming toxic waste into a form usable by plants. Grow-bed media filters are central in the nitrogen cycle in a closed-loop system. That is highly biodynamic, with the variables that tend to change the balance among the various components of the whole system. Optimization of biological processes allows the system-level changes within a specified range but because of self-renewal inherent in the operations, the system shows no overall change. Modulating the grow-bed media is the essential feature of this balancing mechanism. It includes selection of media filters according to their physical attributes. This paper seeks to advance the current understanding of the most critical aspects of aquaponics that could help in developing system designs for a truly aquatic carbon farming.

This study was designed to determine the effect of commercial biofertilizers, namely chitosan, Bacillus spp. and Effective Microorganism formulation on the production efficiency of Genetically Improved Farmed Tilapia (Oreochromis niloticus) and green bean (Phaseolus vulgaris) in an aquaponic system. The intended purpose was to examine if the production of the two integrated species can be optimized by cost-effective methods consistent with the concept of circular economy. While the biofertilizers performed water quality remediation as seen from the dynamics of turnover of ammonia (NH3), nitrite (NH2), nitrate (NO3) and phosphate (PO4) but produced no significant impact on growth of the fish, and the green bean could not attain the fruiting stage. Green beans that generally produce white-purplish flowers which transform into pods dropped off after one week on the plant. The water quality parameters: dissolved oxygen (5.54 to 6.12 mg/L), pH (6.9 to 7.0) and water temperature 26.7 to 27.8oC were in the suitable range but evidently the green bean faced deficiency of nutrients that are needed for fruiting. The nutritional management requires further investigations since the green bean pods are a rich source of human food, and maximum benefits from aquaponics can be derived through their production and faster growth of the fish. The trend of fish growth suggests that the biofertilizers will result in significant growth advantage if the treatment is carried out over a longer faming period.

Effluents from aquaculture systems contain large volumes of chemical substances and microbial load such as polychlorinated biphenyls and antibiotics that are often used to control infection and pathogenic bacteria originating from feed or water. These substances, if discharged, create pollution in the aquatic environment. Mitigating this problem requires implementing appropriate treatment methods. This study investigated the efficiency of uptake of nutrients in the wastewater and reduction of microbial pollution by chitosan. This product is a linear polysaccharide composed of β-linked D-glucosamine and N-acetyl-D-glucosamine and can be extracted from the shells of shrimps, lobsters, crabs and other crustaceans that are discarded in bulk quantities by seafood restaurants. The performance of laboratory-produced chitosan (S1) which was prepared from shells of Pacific white leg shrimp (Litopenaeus vannamei) was compared with that of the commercial grade chitosan (S2). While the latter was more effective in nitrogen and phosphorus removal and reduction of total faecal coliform, the two products were comparable in the uptake of minerals from the effluents from a tilapia culture system. The results showed that S1 and S2 adsorbed the nutrients from aquaculture effluents, especially ammonia (NH4 + ), nitrite (NO2 - ), nitrate (NO3 - ) and phosphate (PO4 3-). However, differences were evident in terms of the efficiency of their removal and duration of treatment required for the purpose. In this respect, S2 performed better. Moreover, the anti-bacterial activity of S2 was higher than that of S1, and this appeared to be linked to differences in surface features of the two products. The chitosan extracted from shrimp waste and processed locally provides a low-cost solution to the environmental problems caused by aquaculture effluents.