START-UP EVALUATION OF ANAEROBIC SYSTEM REMOVING ORGANIC MATTER OF SWINE WASTEWATER

This research was carried out in order to evaluate the start-up of anaerobic reactors working in series removing organic matter of swine wastewater. The pilot system was assembled with a sand retention unit, Thompson flow rate meter, static screen, an equalization acidification tank (EAT) with 8,500 liters, pumping system, two sequencing anaerobic reactors, being the first unit an anaerobic baffled reactor (ABR) and, the second one, an upflow anaerobic sludge blanket reactor (UASB). The ABR showed at the beginning a higher efficiency in removing BOD, mainly due to the solids settling caused by the low superficial loading rate. Latter the efficiency reached the lowest value, about 23%, and after a short period the efficiency went up to 80%. The UASB in the other hand, showed efficiency about 45% at the beginning of the research, however, it maintained high stability with efficiency near to 80%. Latter the efficiency decreased to values lower than 40%. One of the reasons for this abrupt drop was due to the lowering of the environmental temperature.