Hydrobiological Investigation of the Activated Sludge from Sequencing Batch Reactors of WWTP -Hisarya

The operations of the relatively new wastewater treatment plant of Hisarya, Bulgaria were evaluated in the present paper. The bacterial diversity of activated sludge from aeration basins of cyclic type (SBR-method) during the seasons was studied. The Cyclic Activated Sludge System is one of the most popular sequencing batch reactor (SBR) processes. The hydrobiological characteristic of the activated sludge was performed with regular observations by using light microscopic examinations, but also by evaluation of the flocculation ability and settleability. The presence of positive bioindicators - Aspidisca and Epistyllis species during the investigated period of time (2012 Year) was established, which confirmed the gut purification of the wastewater and the carrying out of the nitrification process. Moreover, the results obtained demonstrated that the performance of the SBR maintained high level, and the SBR system remained stable during this study.