Thermal effects on the hydraulic performance of sedimentation ponds

Abstract

Numerous pilot and computational studies have investigated effects of inlet, outlet, baffles and geometry on the hydraulic performance of sedimentation ponds in water and wastewater treatment plants. However, no full-scale study has addressed buoyancy effects caused by variations in the ambient temperature and the real-time temperature of the fluid at the inlet. This might significantly affect the hydraulic performance of sedimentation ponds. For the first time, we conduct representative simulations to study effects of variations in the temperature on the hydraulic performance of a plant-scale rectangular pond. It is shown that even a small difference between the temperature at the inlet and the bulk flow inside the pond could augment thermal stratification, as a result of buoyancy forces. The results reveal that buoyancy forces in a typical pond would decrease the hydraulic retention time and the effective volume. We suggest that understanding the effect of temperature profiles on the hydraulic performance of ponds should be a prerequisite for improving the design and configuration. © 2019 Elsevier Ltd