Aquaponics is the combination of aquaculture and hydroponics. Aquaculture is the system of raising and harvesting fish, mollusks and crustaceans in all types of water environments. This is done in an enclosed and controlled environment wherein all the physical and chemical conditions can be altered like the water pH, size of the aquaculture pen and the amount of food to be fed.
On the other hand, hydroponics is the method of growing plants without soil. Instead, water with a complete set of minerals good for the plants is used. Combining the two methods, aquaponics is born. In this system, both the aquatic organisms and plants are grown in one environment. The fish excretes waste products in the water and the nitrifying bacteria present in it convert these waste products into nitrates and nitrites in a process called nitrification.
The nitrates and nitrites now serve as nutrients for the plants. At the same time, the plants filter the water in order to provide a clean environment for the aquatic organisms. By combining the two systems, both plants and aquatic organisms benefit from it and no by-product is wasted in the process.
The aquaponics system started as early as the time of the Aztec people. They started to plant in areas called chinampas that refer to stationary islands in a shallow lake. In modern times, China, Thailand and Indonesia were the first countries to cultivate their rice in paddy fields and at the same time raise aquatic organisms such as eels and loaches in the paddies.
There are three components in using the aquaponics system. There should be a plant, an animal and bacteria. Plants are usually green leafy vegetables such as Chinese cabbage and lettuce. Other types like tomatoes and basil can also be cultivated. For the animal, freshwater fish is used like the tilapia, which is also known as St. Peter’s fish. This fish is commonly used for home-based aquaponics since they are easy to be raised.
The last component of the aquaponics system is the nitrifying bacteria. It is an important component since it acts like a filter in the enclosed environment. It reduces the toxicity of the water by converting the waste products of the animal into useful by-products. Ammonia is released into the water by the fish as a waste product of their metabolism. The accumulation of ammonia in water is very toxic for living organisms so it is necessary to remove them.
Plants can use ammonia but nitrates can be assimilated more easily. Nitrifying bacteria such as the Nitrosomonas and Nitrobacterium are capable of converting ammonia into nitrates and nitrites. The roots of the plants should have a large surface area where the nitrifying bacteria can gather. The process of nitrification causes the water to become acidic so bases like potassium hydroxide and calcium hydroxide can be added in order to neutralize the pH of the water.
Worms can also be added in the system in order to get rid of any solid materials that build up at the bottom of the tank. The aquaponics system is a huge innovation in the farming and fishing industry. It is easy to set up and only requires three major components. It is also eco-friendly and has many benefits. By combining the aquaculture and hydroponics technique, it is like hitting two birds with one stone.