Optimization of oxygen transfer coefficient and standard aeration efficiency of a Venturi-type aerator using response surface methodology

Abstract

This research focuses on determining the optimal parameters for maximizing dissolved oxygen (DO) when using a Venturi-type aerator, considering two objectives: oxygen transfer coefficient corrected to 20°C (K_La₂₀) and standard aeration efficiency (SAE). The determination of the optimal parameters for the Venturi-type aerator was carried out under thirty experimental conditions of a face-centered central composite design (FCCD), involving four influencing variables: Venturi convergence angle (α), Venturi divergence angle (β), water flow rate (Q_w), and air flow rate (Q_a). Response surface methodology (RSM) was used to evaluate the experimentally collected data. The analysis of the experimental results showed that the most suitable conditions for  were 45° convergence angles and 15° divergence angles, with a water flow rate of 40 L/min and an air flow rate of 0.9 L/min, resulting in a  value of 4.278 h^-1. For optimal SAE values, the study found that the Venturi convergence angle of 45°, the Venturi divergence angle of 15°, the water flow rate of 20 L/min, and the air flow rate of 0.9 L/min should be set. These parameters gave an SAE value of 0.0343 kgO₂/kWh. Analysis of the regression equations developed in this study showed that the coefficients of determination (R²) of the K_La₂₀ and SAE prediction equations were more than 90% for both equations. Therefore, the response can be accurately predicted, and these equations serve as guidelines for the design of the most appropriate Venturi-type aerator in practice.