Design of a recirculating aquaculture system for Uganda fish farmers.

Abstract

Aquaculture is the science art and Business of farming or cultivating fish under controlled conditions. The gap between the supply of fish and the demand for fish is widening both in Uganda and globally, current fish farming methods commonly practiced in Uganda include pond culture and flow through tanks technology. However, these methods are not applicable in areas which are densely populated and or with Limited supply of clean ground water. This project has come out with a design of a recirculating aquaculture system (RAS) to enhance commercial fish farming especially in urban areas, and rural areas with in adequate fresh water supply with a case study at AGROSWITEC's demonstration farm in Wobulenzi Luwero district. A good number of literature sources and data were obtained and carefully analyzed in order to generate this design. Information about general system lay out, studying various water quality parameters favoring fish farming, several fish species in farmed in Uganda. Survey data was collected from which a contour map was drawn, and slopes calculate to establish relative positioning of system components. RAS system components include culture tank, settlement tank, rotating biological contactor filter, reserve, tank, oxygenation unit and pump these were properly sized using various design equations and assumptions. Structural analysis calculations aided in determining diameters of iron bars, relative positioning of iron bars and the formwork required. A computer program in MS Excel was developed to determine relative pipe sizes and flow rates from one component to another. A cost benefit calculation was conducted to appraise this project with various assumptions and projections. Therefore by adopting a recirculating aquaculture system fish farming will be possible in densely populated areas plus regions like Karamoja which is semi-arid.