USO DE TRAÇADOR SALINO PARA A DETERMINAÇÃO DE CONDIÇÕES HIDRODINÂMICAS EM WETLANDS CONSTRUÍDAS

Abstract

Hydrodynamics has a relevant influence on sewage treatment, mainly on the contact time between microorganisms, the support medium and the sewage, intervening in the physical, chemical and biological reactions in the reactor. The work sought to investigate through mathematical models and with the support of the application of the use of saline tracer the hydrodynamic conditions in a hybrid system of constructed wetlands (WC). Through the calculations and measurements carried out, we obtained values ​​for volumetric and hydraulic efficiency, short circuit index, dispersion model, series tank model and the real and theoretical hydraulic detention time in the studied WCs. This study was carried out at the IF Goiano – Rio Verde, in the WC pilot station, composed of a vertical flow WC in series with a horizontal flow WC. The “pulse stimulus-response” method was used for the hydrodynamic test, where sodium chloride was used as a tracer. 0.55 kg of NaCl was applied inside the effluent storage tank, then shaking and releasing the sewage into the WC, setting the pulse. The electrical conductivity of the sewage at the exit of each cell was measured at intervals of 30 minutes. Thus, he obtained the time that each portion of the effluent volume takes to travel through the toilets. With the results obtained, it can be said that: the set of WC presented a slight adjustment between the idealized models and the local reality, and the vertical WC presented a slight deviation from the complete mixture flow flow, with a slight tendency to the dispersed regime . The horizontal WC, on the other hand, presented a high deviation to the piston flow flow, due to the fact of presenting a high level of particle dispersion, with the existence of preferential paths, still having a slight tendency to dispersed flow.