The Efficiency of a Sequencing Batch Biofilm Reactor in Organic Carbon and Phosphorus Removal

A laboratory sequencing batch biofilm reactor (SBBR), operated for a period of 158 days, was used to treat domestic-strength synthetic effluent. The biofilm reactor comprised a bulk fluid reactor, a biofilm plastic module, a synthetic wastewater feed tank, and pneumatic devices with pneumatic controls. The reactor cycle time was 8 h, and its operation consisted of five phases: feeding (59 min), mixing (1 min), anoxic/anaerobic (3 h), aerobic (3 h), and settling (1 h). At total chemical oxygen demand (COD_T) loading rates of 8.8 g COD_T m⁻² d^{− 1} and 1.2 kg COD_T m^{− 3} d^{− 1}, expressed in terms of the plastic module surface area and reactor volume, respectively, the SBBR had average removal rates of 8.3 g COD_T m^{− 2} d^{− 1} and 1.1 kg COD_T m^{− 3} d^{− 1}, or 94%. Total orthophosphorus (PO₄-P_T) and filtered orthophosphorus (PO₄-P_F) removals were 44% and 50%, respectively.

Keywords:

• Carbonaceous oxidation
• Sequencing batch biofilm reactor (SBBR).

ACKNOWLEDGMENTS

We are grateful to Coffey Construction Ltd., Athenry, Co. Galway for support of this work. We acknowledge the technical help of M. Rathaille, M. O'Brien, and G. Hynes (NUI, Galway).

Notes

^a AF, sample taken after the reactor was fed and mixed; AAN, sample taken at the end of the anaerobic phase; AA, sample taken at the end of the aerobic phase; AS, sample taken at the end of the settlement phase.

^b Removal rate is expressed in terms of the surface area of the BIOdek module (3.8 m²) loaded at 27.6 L d^{− 1}.