Use fish poop to feed plants, conserve water

Want to conserve water and grow plants indoors without soil? One can do that by using fish poop.

IIT-Guwahati student Siddharth Nimkar and his batchmates have developed a small scale model, consisting of a fish tank and a soil-less plant bed, to enable one to grow plants indoors without soil.

Plants can be grown using fish excreta through a method known as acquaponics, in which fish are raised in a tank and the water mixed with the fish excreta is used for watering plants.

In essence, the fish poop is food for plants and the plants clean the water for the fish.

"The fish kept in a fish tank excrete nitrogenous waste into the water. The waste acts as nutrient source for plants. The nutrient-rich water is pumped into the water bed where plant roots are dipped in and they absorb the nutrients. There is no soil," Nimkar told IANS.

"The fish waste is converted by bacteria into nitrate which can be easily absorbed by plants. The plant bed is provided with gravel for bacteria to grow. Through this, the water is filtered and is diverted to the fish tank. This forms a cycle," said Nimkar who is pursuing a Ph.D in molecular biology at the institute.

The key advantages are a high density of production and less dependence on climate and soil conditions, said Nimkar, adding the technique wastes only one percent of water.

"There is less grain spoilage and reduced transportation cost because it could be set up within the city, he said. Setting up a small scale system costs around Rs.3,000, he said.

The small scale model was showcased as a part of the institute's Prakriti Environmental Club activities and involves students Dhruv Gupta, Arun Dhillon and Yoganand.

--IANS

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