Assessing the Utilization of Waste from Aquaponics System as Nutrients Contributing to the Growth of Water Spinach and Tank Fish

Abstract

Due to having plentiful water resources, Bangladesh offers significant potential for fish farming. Aquaponicsas a bio-integrated multi-trophic system that combines hydroponics (the growing of soilless plants) and re-circulate aquaculture (the culture of fish) to create a symbiotic relationship between fish, microorganisms and plants. This study was carried out for 95 days at the aquaponic laboratory of Khulna Agricultural University (KAU) to access the utilization of waste from tank water as nutrients affecting the growth of both water spinach and fish using two different medias-only bricklets (𝑇1)and mixture of bricklets and used tea leaves(𝑇2). For the purpose of growing vegetables and raising fish, six 20-liter plastic containers and a 750-liter water tank were employed respectively. Fish and water spinach samples were taken every two weeks. Electric conductivity (EC), carbonate (CO3), hydrogen carbonate (HCO3), total nitrogen (Total-N), phosphorous (P), potassium (K), sulphur (S), and sodium (Na) were measured in the soil testing Laboratory at KAU. Bacterial activity in the media and roots of plants was found to be higher in influent water than effluent water, indicating that plants were properly utilizing. "Microsoft Excel 2010" and Statistical Package for Social Science (SPSS) were used to analyze the descriptive statistics and determine the significance level as well. The greatest average plant measurements for 𝑇1were 36.40±3.55 cm in height, 58.81±23.35 in weight, and 93.90±38.52 in terms of leaves. In 𝑇1and 𝑇2, a total of 1.57 kg and 1.21 kg of water spinach was harvested respectively. The length and weight gain percentages were 61.45 and 155.51 at the conclusion of the trial, while the survival rate and FCR were found to be 100% and 1.51, respectively and at the end of the study average fish production was estimated 9.91 kg. The technique actually produced more fish and vegetables while using less water causing no adverse effects on the environment. Through a symbiotic link between the fish and plants, the system effectively used fish waste in plant development and fish production as well. In order toaddress the environmental issues, the system might be placed in densely populated urban areas to grow fish and vegetables on rooftops and in backyards.