Physical modelling of water movement in acquaculture ponds

The following note purposes the hydraulic characterization of the waste water movement within phytotreatment ponds, collecting water coming from an intensive fish farm, located in the Orbetello area, before flowing the water into the Orbetello lagoon (Grosseto, Italy) with the aim of increasing the residence time and, then, water quality. The problem is faced through an experimental approach with trials on a physical model reproducing in scale the real pond. Visualization techniques, through the use of a tracer let in at the entrance of the physical model and the reconstruction of the time-concentration curve (NaCl solution) on samples taken at the output, allowed to find out the efficiency of the system, tested under different conditions. In particular, baffles have been used to improve the system efficiency, reducing recirculation areas which are not involved in the water movement within the pond.