Techno-economic feasibility of rainwater harvesting system for vertical aquaponics in Brunei Darussalam

Abstract

Rainwater harvesting is one of the most promising alternative sources of fresh water, particularly in countries with abundance of rainfall all year round, and this is especially important for the agricultural sector, which traditionally requires plenty of water. This work studies the feasibility of implementing a rainwater harvesting system for an existing aquaponics farm in Brunei. A rainwater harvesting model, with system and economic measurement, has been developed, with local meteorological and market data as well as local aquaponics farm used for illustration purpose. Analysis has shown that the rainwater harvesting system has the potential to save up to 127 m3 of water with a system reliability of up to 67.5% using tank sizes ranging from 0-5 m3. The system is shown to be feasible with a 3.3 m3 tank that would require approximately B$2,300 to construct; giving water unit cost at par to the current local water price. These results indicate the potential of rainwater harvesting system for agricultural use in the local context. Although local data have been used, the model can also be adapted for analysis at other localities, and for other applications, such as for domestic or industrial applications.