Utilization of Effluent Fish Farms in Cultivation Using Aquaponic System

Abstract

The most prevailing issues of the modern world are food and water crises. Due to scarcity of water and land, it is not possible to consume the pesticide affected food nor grow plants individually. Under such conditions, there arises a need for portable agricultural system which uses less water, space and is purely organic. One such solution is a small scale aquaponic system. Aquaponics is the integration of aquaculture and hydroponics. Aquaculture is the cultivation of aquatic animals or plants for food and hydroponics is the process of growing plants without soil. In this system,the fish consume food and excrete waste primarily in the form of ammonia. Bacteria convert ammonia to nitrite and then to nitrate. The aquaponic system produces two food sources for consumption, the crops grown in the bed and fish reared in the tank. This system has the potential to increase the stability of families by helping them become financially secure. It provides a simple and practical solution to the food security issues. It uses resources efficiently and creates little waste. A structure of dimension 1.75×0.75×1.15 m was fabricated. The PVC pipes with plants are supported on the structure. Aquaponic system consists of a fish tank with a volume of 500 l in which the fish is reared. The fish used in this experiment was Tilapia. The sewage of the tank consists of fish waste. The ammonia excreted by the fish is being continuously removed by the bacteria present in water. Nitromonas bacteria present in water oxidize ammonia to nitrite and nitrobacter converts the nitrite to nitrate.Nitrate is the form in which nitrogen is absorbed by the plants.The water is pumped from the tank to the different pipes, plants absorb the nutrients and then water is returned back to the tank.Different flow rates of 2 l min -1 ,3 l min -1 and 7.5 l min -1 were set by adjusting the control valves.The medium used was gravel. The plants were planted in gravel media and different flow rates were maintained. The seedlings of amaranthus, CO1 variety were used for planting.The parameters which affect the bacterial growth are pH and EC. The EC value should range from 0.1 and 0.4 dS/m. The pH varies from 5 to 8. EC and pH were measured in weekly basis using pH meter and EC meter. The biometric parameters like plant height, node to node distance, root length, number of leaves, yield are measured. The water quality parameters like nitrate, nitrite, phosphate, potassium are measured in CWRDM, Kozhikode. The result obtained from the experiment was that the biometric parameters such as plant height, node to node distance, root length, number of leaves and yield are higher in the plants grown under a flow rate of 7.5 l min -1 . The least performance was observed in the plants under a flow rate of 2 l min -1 . The water sample from aquaponic system was also tested.