Remoção de fósforo de esgoto doméstico em lagoas de polimento tratando efluente de reator UASB

Abstract

The contribution of phosphorus in water bodies is considered as one of the main causes of eutrophication, therefore, its removal becomes of great importance for the environment and for public health. Within this context, the present research sought to evaluate the removal of phosphorus in a sewage treatment system, consisting of anaerobic pretreatment in the UASB reactor and post treatment in polishing ponds with depths of 0.2; 0.4; 0.6 and 1.0 m, operated in sequential batch regime. The data used were collected in periods with higher and lower solar radiation (summer / winter). The results obtained showed that the processes that develop in the polishing ponds cause an increase in pH, which in turn leads to the removal of phosphate by precipitation in the presence of calcium ions. It was possible to obtain very low concentrations of phosphorus (1mgP.L-1) when the pH in the pond reached values above 9.5. It was also observed that phosphorus precipitated in the lagoons in the form of calcium hydroxyapatite C10(OH)2(PO4)6.In this way, the association of UASB reactor with polishing ponds becomes a viable alternative for the treatment of sewage, be a great option to replace treatment systems that use conventional ponds.