Aeronautical engineer who uses fish waste in vegetable farming


An engineer is proving that it’s possible to turn fish waste to fertilizer. Michael Ibuba an Aeronautical engineer by profession launched an aquaponics farm which he turned into a full-blown business. 

In 2015,Mr. Ibuba started an Aquaponics farm, a method of growing plants and fish in a symbiotic environment, where the waste produced by fish is used as a fertilizer for the plants and the plants, in turn, clean the water for the fish.

In Aquaponics, he  says, ammonia, a by-product of fish, is not taken at face value – the growth beds where vegetables are grown work the magic of converting the ammonia from nitrite to nitrate, a process biologists call nitrification. Nitrate is a fertilizer and that is how plants get their nutrients. Clean water forms a good ecosystem for the fish.

The farm is tucked in a 13-meter by 7-meter greenhouse, where he grows onions, beans, lettuce, spinach, ‘managu’, celery, capsicum and tomatoes. The greenhouse is characterised with vertical towers made up of pipes and three fishponds.

Ibuba says that the need to have a “permaculture system for growing food” is what inspired the venture, adding that his crops are safe as there are no pesticides or chemically manufactured fertilizers used in the farming process.

‘’No pesticides or fertilizers are added to the system,” he says. “If you add any of those I can guarantee you that all the fish will die. This project can be done in areas where there is no water. In such a system we use less than 90 percent of what other farmers use.’’ 

Since the crops are grown without the use of artificial fertilizers, food that is aquaponically cultivated is healthy for human consumption. Fish waste serves as a natural fertilizer in aquaponics, giving the plants the nutrients they require to develop. Greater control over water quality is also made possible by the closed-loop system, which lowers the danger of heavy metals or other pollutants contaminating the water supply.

Ibuba says that the cost of setting up an aquaponics farm ranges from Sh250,000 to Sh1.8 million, with return on investment estimated to take 2 to 5 years depending on the market and what is in demand. He notes that in a good harvest, he could rake in Sh1 million from his aquaponics setup in a month. 

‘’If you want to venture into farming and you don’t have large acres of land, aquaponics can be done in very small plots and the yields are also high. Another benefit of this type of farming is that it can be done in all areas and with very minimal amounts of water,” he says. 

In Aquaponics, no soil is used to grow the crops. Farmers use pumice rocks instead. These rocks are used as a growing medium in aquaponic systems because of their unique characteristics – pumice is a lightweight, porous volcanic rock that helps to keep the proper ratio of water and oxygen for healthy plant growth while also providing a stable framework for the growth of plant roots.

Pumice has a pH that is neutral and does not alter the water chemistry in the aquaponic system, which is crucial for preserving a healthy environment for both fish and plants. The pumice’s huge surface area is also ideal for the growth of good bacteria, which are necessary for turning fish waste into nutrients that plants can use. Pumice is also preferred in aquaponics because it lowers the need for soil, conserves land resources, and enables the growth of crops in tiny, or constrained locations.

Ibuba points out that aquaponics is a useful instrument for enhancing food security. He argues that the farming technique enables the production of both fish and vegetables in a “condensed and regulated environment” while utilizing less water, land, and other resources than conventional farming. 

‘’Aquaponics can be very beneficial to Kenyan farmers if they adopt it as one of their farming methods. It produces healthy food and very little manpower is needed to get high yields. Again it is also easy to operate once you have the setup together unlike traditional farming,’’ he explains.

He adds that the “closed-loop technology” decreases waste and boosts productivity, enabling the year-round production of fresh, nutrient-dense food, and can be the best option for regions with little access to arable land or water.

He notes that aquaponics can help reduce poverty and enhance community health and well-being by boosting food production capacity especially in places where food security is a concern.

Aquaponics bears its challenges such as electricity because the system is highly dependent on electricity, but one can leverage on alternative energy sources. In addition, farmers can’t plant crops can’t plant crops with large stems such as maize. 

‘’The biggest challenge we had was electricity but this could be overcome. We used the solar system to navigate this,’’ Ibuba says. 

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