Importância da frequência de descarte de lodo na eficiência dos decantadores de estações de tratamento de água em ciclo completo

Abstract

In this work, different periods of discharge of the sludge stored in the decanters of the ETA Bolonha had been evaluated, with the purpose to recommend the operational routine that presents the best ones results in the efficiency of the decanters. The three experimental phases had been divided in three stages: being in phase 1 evaluated the efficiency of the current operation routine of the decanters what is the total discharge of sludge in 12 in 12 days. In phase 2, the operational routine was modified to a daily discharge during the time of 5 minutes and so it coud take care of the recommendations of the executive project; by the other hand, in phase 3, the operational routine was modified again, discharge of sludge of 5 in 5 days during the time of 5 minutes, in order to getting better results of efficiency. In these three phases it was realized the control of total suspended solids, dimming and color in the effluent tributary and, as well as quantified and characterized the sludge generated in the decanters. With the research it was possible to observe that according to the point of view of efficiency of the decanters, the implemented operational routine in phase 3 (discherge of sludge to each 5 days) it was showed more adequate. By the way, it recommends that tests with other operational routines should be done in order to remove the sludge deposited in the decanters to diminish the losses of water of this operation. Moreover, it is important to study other ways to remove the deposited sludge in the intermediate tray of the decanter to prevent the accumulation of sludge on tray.