Emprego de lagoas seriadas após reatores RAC-UASB para tratamento de águas residuárias de suinocultura

Abstract

This research presents the behavior of one facultative pond and three maturation ponds in series such as post-treatment effluent from a two stages anaerobic system, composed of an anaerobic baffled reactor (ABR) followed by an upflow anaerobic sludge blanket reactor (UASB), in full scale, treating swine effluent. The maturation ponds were worked in three different phases depending on the depth, being the first phase with 0.40 m, second with 0.60 m and third with 0.80 m. The parameters evaluated were: air temperature, pH; dissolved oxygen (DO); biochemical oxygen demand (BOD); chemical oxygen demand (COD); total solids (TS); total volatile solids (TVS); total suspended solids (TSS); volatile suspended solids (VSS); ammonia; total Kjeldahl nitrogen (NTK); nitrite (NO2); nitrate (NO3); phosphorus (Pt); coliforms; Escherichia coli and helminth eggs. At the end of the three phases the ponds, after dryingponds, the sludge was collected for analysis of the volume, weight, coliforms and viable helminth eggs. The global system showed efficiency of removal above of 98% and 96% for BOD and COD, respectively, given the standard of effluent discharge established by DN COPAM-CERH 01/2008, however the ammonia was very above the standard. The ponds were not efficient in the removal of nutrients and coliforms due to the low hydraulical detention time (HDT), however had produced effluent free of helminth eggs. The analysis of coliforms in t he ponds sludge attended reuses in agriculture, according to Resolution nº 375/06 of the CONAMA, for Escherichia coli, in ponds LF and LM3. The sludge showed high concentrations of viable helminth eggs not attend the standard of this Resolution.