Efficiencies of Organic Matters and Nitrogen Removal at Different Recycle Ratios in a SMBR System

The experiment in this study was conducted using wastewater treatment system constructed with anoxic reactor, selector, and aerobic reactor. The Submerged Membrane Bioreactor (SMBR) system was operated with a design flow of 50 m3/day, and the vertically double layer-submerged biological membrane was integrated with aerobic reactor. The objective of this study has been to help move towards an optimal design on the operation of submerged reactor treatment plants. In particular, this study has focused on the organic matters and nitrogen removal efficiency according to recycle ratios. The obtained results of experiment are as follows: BOD and COD, which are indicators of organic compounds were 96.50−98.50% and 92.90−97.00%, respectively. The measured ranges of BOD and COD indicated a reliable treatment efficiency, and similar efficiency was observed for suspended solids and coliform removal. These results could be applied to good effluent quality for suitable standards of the reuse water. The Recycle ratios in this study were 1, 1.5, 2, and 3; and the corresponding T-N removal efficiencies for each ratio were 54.10%, 69.80%, 76.60%, and 81.90%, respectively. It is observed that the removal efficiencies are increased in proportion to the recycle ratio. While the recycle ratio was increasing from 1 to 3, the removal efficiency increased 15.70%, 22.50% and 27.80%.