Pós-tratamento de efluentes de reator UASB em filtro anaeróbio submerso e filtro de areia de fluxo intermitente

Abstract

The use of UASB reactors for the treatment of domestic sewage is considered a consolidated technology, however, even with relatively large removal efficiency of organic matter, rarely attending several other parameters established by environmental agencies. The research investigated the performance of the posttreatment of UASB reactor effluent in anaerobic filter (FAN) and sand filter of intermittent flow (FaFint), with the purpose of evaluate the removal of organic matter, suspended solids, pathogenic organisms and keep the forms of nitrogen, in order to obtain an effluent for agricultural reuse. The experimental system consisted of a UASB reactor followed by anaerobic filter and sand filter of intermittent flow. The experimental system was operated with average daily flow of sewage of 630 L/day. For the FaFint feeding occurred through a siphon, that operated for 3 cycles with daily flow of 105 L/cycle. The average removal of the UASB reactor was 63% of COD gross, with final removal of COD gross in the effluent end of the FAN and FaFint of 80 and 86%, respectively. The removal of total suspended solids and volatile was 88% in the final effluent of FAN. While the FaFint removed 90 and 91% of total suspended solids and volatile, respectively. Satisfactory nitrification was obtained on the FaFint, producing the final effluent with 34 mgN-NO3.L-1 and 8 mgNTK.L-1 and 99,5% of removal helminth eggs. The experimental systems studied showed satisfactory efficiency in removing organic matter, solids in suspension, being, thus, adaptive systems to small communities, can enable the reuse of effluents in agriculture.