Determinación de la velocidad del fluido en las lagunas de maduración de Lidsey.

Abstract

The present study was carried out in the municipal treatment plant of Lidsey located in Bognor Regis at the South of England. The tertiary treatment of such plant consists of three (3) parallel maturation ponds (North, Plant and South), with similar dimensions (122mx14mx1m). The South pond  three baffles, deferring its geometry with respect to the other two ponds. This research was developed in the tertiary treatment phase, and its goal was to study the movements caused by the viscosity of Eddy, dead spaces, short circuits, and the velocity of the fluid in different depths (surface, depth P = 25, 45, 60 cm, measured from the surface toward the bottom of the lake). In order to measure the velocity on the surface, floatable pieces of similar size and weight were used, with a degree of submergence around 98% (therefore the effect of the wind on the such pieces was avoided). The flow velocity under the water level was determined with dopes constructed in the laboratory and calibrated to the depth required before its use. In addition, a simultaneous experiment with floating objects and WT Rhodamine was carried out. Thus, the trajectory of the movement of the fluid was observed with each instrument, being concluded that both should be used, in order to obtain the desired data and know the effect of the wind on the fluid. The best hydraulic behavior was achieved by the pond with baffles, with the lowest effect of the viscosity of Eddy and the greatest time for the exit of the flow jet, in comparison with the original pond. In all the ponds the highest velocity was measured on the surface, and a zero velocity in the depth of 60 cm. The hydraulic patterns of the baffled pond was predicted using the HYDRO‐3d model, resulting in similar forecasts to the experimental values, with regard to changes of velocity of the fluid (short circuits), areas with higher velocities and dead spaces.