Feasibility of a wind-powered aeration system for small-scale aquaculture in developing countries

Abstract

Small-scale aquaculture is an important source of income and food in many developing countries. However, yields from many aquaculture ponds can be limited due to the lack of dissolved oxygen (DO). In the developed world, aeration systems are employed to increase stocking density and yields. However, these systems are expensive and energy intensive, putting them out of reach for farmers in many developing countries. This paper describes a new Wind Powered Aeration (WPA) concept, which can improve DO content in small-scale fish ponds. The WPA concept consists of a Vertical Axis Wind Turbine (VAWT) coupled to a sub-surface impeller. The impeller pulls water from the pond bottom to the surface through a draft tube. This introduces circulation, limiting DO losses and improving overall DO content. This paper presents the concept and models used to understand the performance. An experimentally validated computational fluid dynamics (CFD) model was used to enhance a bench-scale version of the impeller. The performance for the full-scale device was then estimated using CFD. These CFD results were used in a DO model to estimate the device impact. Results showed the WPA system could increase the overall DO content by 48%. This demonstrates the approach has the potential to improve DO and yields for small-scale aquaculture.