Nitrogen removal using a vertically moving biofilm system
Rodgers, M.; Burke, D.
Water Science and Technology a Journal of the International Association on Water Pollution Research 47(1): 71-76
2003
ISSN/ISBN: 0273-1223 PMID: 12578176 Document Number: 562777
This laboratory study established the efficacy of a new experimental biofilm system for the removal of nitrogen from synthetic waste water. The system consisted of six reactors in series: one anaerobic, one anoxic and four aerobic reactors. In both the anaerobic and anoxic reactors, a plastic cuboid module was repeatedly moved up and down in the waste water, while being totally submerged at all times. In each of the aerobic reactors, an identical module to that used in the anaerobic and anoxic reactors was intermittently and repeatedly immersed in and lifted out of the waste water. All the individual reactors had a bulk fluid volume of 28.2 litres and the average temperature of the waste water was approximately 10 degrees C. Each module consisted of crossflow corrugated plastic sheets with a surface area of 1.824 m2. The nitrate recycle flow from the fourth aerobic tank to the anoxic tank was twice the inflow to that tank. In the anoxic reactor, filtered chemical oxygen demand (COD) was removed at an average rate of 2.22 kg COD/m3 per day and nitrate-nitrogen was denitrified at a rate of 0.42 kg NO3-N/m3 per day. The average nitrification rate in the second aerobic reactor was 0.12 kg NH4-N/m3 per day. The new biofilm system was simple to construct and operate.