Analysis and hydraulic improvement of a maturation pond using Computational Fluid Dynamics

Especially in small communities, little attention is paid to the hydraulic characteristics of wastewater treatment systems. Motivated by this problem, and using the ANSYS fluid dynamics software, the hydrodynamic evaluation of the residual water flow in a rural plant maturation pond was carried out. For the stationary modeling of the velocity and turbulence fields, the standard k-ε model was used; and for transient modeling of virtual tracer transport, the species transport model without chemical reaction was used. Subsequently, the analysis of the distribution of retention times was carried out, in order to obtain the flow patterns that govern the hydrodynamics of the pond. The results revealed the presence of hydraulic short circuits, stagnant zones, and recirculations, due to design deficiencies and operating conditions over the years. Given this situation, and by bibliographic recommendation, new modified geometries were proposed with longitudinal and transverse baffles at 70 and 90% in relation to the width and length of the pond. As a result, the hydraulic characteristics improved notably in all cases; however, the models configured at 90% achieved higher efficiency.