The rapid growth of the global population, projected to reach 10 billion by 2050, poses significant challenges in terms of land scarcity and protein shortages, compelling nations to intensify all sectors of food production, including aquaculture. It is crucial to maintain the ecological balance in the food production cycle by managing the carbon and nitrogen cycles effectively, as unchecked emissions can lead to soil degradation, water pollution, loss of biodiversity, and contribute to climate change. Balance is maintained by ensuring that carbon emissions in one system are offset by another and that nitrogen emissions are similarly neutralized.
Biofloc Aquaculture Technology (BFT) can offer a comprehensive solution to these challenges, enabling intensified fish production of 1000-3000 tons per annum on just 3 hectares of land, with minimal water usage, negative carbon footprint, and low nitrogen emissions. BFT transforms organic waste into microbial bioflocs that serve as a natural, protein-rich food source for species grown within an enclosed aquaculture system, decreasing the reliance on external inputs like feed and chemicals. Additionally, BFT can enhance yields and economic performance while promoting the efficient use of resources such as water and energy. In a BFT system, nitrogen generated during fish production, is neutralized using carbon sources like molasses, a byproduct of the sugarcane industry, and rice bran, a waste product from rice polishing. The fish then utilise the bioflocs as a feed source. Additionally, nutrient-rich water from biofloc systems can serve as a valuable input for aquaponics.
Our study utilized tanks of 60, 100, 110, and 250 cubic meters to produce 2, 3, 3.3, and 8 tons of tilapia, respectively, with a feed conversion ratio (FCR) of 1:1. Molasses, calculated at containing 24% carbon, was applied to the tanks at a carbon-to-nitrogen (C:N) ratio of 20:1. The results demonstrate a land footprint of 0.0025 square meters per kilogram of fish produced over a 10 year period of production, and a water footprint of 22 litres per kilogram of fish. The positive carbon footprint of 1025 kg CO2e from electricity consumption, is offset by the carbon in the molasses used to neutralize nitrogen emissions. By incorporating solar energy to eliminate the carbon footprint from electricity consumption, this project could generate carbon credits for use in carbon transition budgeting.
The commercial potential for biofloc technology in Ghana is significant. Ghana’s aquaculture development plan aims to significantly increase fish farming output by 136% by 2027 which will take fish farming output from approximately 89,400 tonnes to 211,600 tonnes by the end of 2027. The plan includes measures to enhance the performance of fish farms, improve environmental standards and address challenges such as the high cost of fish feed. The application of biofloc technology in tilapia production in Ghana has the potential to allow for intensification of fish production within the same or smaller farming footprint, with a reduced carbon impact, reduced water usage and reduced farm gate production costs / higher profitability.