ANAEROBIC BIOFILTER USED FOR POST-TREATMENT OF THE EFFLUENT OF AN UASB REACTOR – A FULL-SCALE STUDY

Abstract

There are several technologies for the treatment of domestic wastewater. The anaerobic reactors and waste stabilization ponds are used in wastewater treatment in tropical regions. The most common alternatives used for post-treatment of effluents from anaerobic reactors are maturation pond, anaerobic biofilter, aerated ponds and activated sludge. The aim of this study was to evaluate the applicability of an anaerobic process (anaerobic filter) for post-treatment of effluent from the UASB reactor treating domestic wastewater in the city of Palmas, Tocantins state, northern Brazil. The bamboo has been used as a means of support of the anaerobic filter. The studies were based on analysis of samples taken during the treatment system. Samples were collected weekly at three points of the experimental system: (1) raw sewage, (2) the anaerobic reactor effluent and (3) final effluent of the anaerobic filter with bamboo. The study carried out in anaerobic filter confirmed the applicability of the anaerobic filter unit as post-treatment process. The system has high efficiency in removing suspended solids. In the case of variable BOD, the effluent of the experimental system met the discharge standards throughout the monitored period, according to the Brazilian resolution, CONAMA No. 430/2011. However, the experimental system showed low removal of nutrients (nitrogen and phosphorus), indicating that the anaerobic reactors have a poor ability to remove these elements in the treatment process.

Key Words: anaerobic filter, bamboo, UASB reactor, wastewater.