Treatment of nitrogen and phosphorus in highly concentrated effluent in SBR and SBBR processes.
Various sludge treatment processes produced supernatant with high ammonia concentration from 500 to 2,000 mgN/L and generally high phosphate concentration. Conversion of ammonia into nitrite via partial nitrification has proven to be an economic way, reducing oxygen and external COD requirements during the nitrification/denitrification process. Two processes with biomass retention are studied simultaneously: the sequencing batch reactor (SBR) and the sequencing batch biofilm reactor (SBBR). At a temperature of 30 degrees C, the inhibition of nitrite-oxidizing bacteria due to high ammonia concentration has been studied in order to obtain a stable nitrite accumulation. This work has confirmed the effect of pH and dissolved oxygen on nitrite accumulation performance. During a two month starting period, both processes led to nitrite accumulation without nitrate production when pH was maintained above 7.5. From a 500 mgN/L effluent, the performance of the SBR, and the SBBR, reached respectively about 0.95gN-NO2-/gN-NH4+, and 0.4gN-NO2-/gN-NH4+. The SBBR appears to be more stable facing disturbances in dissolved oxygen conditions. Finally, the maximal phosphate removal rates obtained in the SBR reached 90%, and 70% in the SBBR, depending on ammonium accumulation in the reactor. Ammonium phosphate precipitation is likely to occur, as was suggested by crystals observation in the reactor.
Pambrun
V
V
Laboratory of Environmental Processes Engineering, Department of Industrial Processes Engineering, National Institute of Applied Sciences, INSA-GPI-LIPE, 31077 Toulouse Cedex 4, France. pambrun@insa-tlse.fr
Paul
E
E
Spérandio
M
M
D018441:Biofilms; D018533:Biomass; D019149:Bioreactors; D006863:Hydrogen-Ion Concentration; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism; D009576:Nitrobacter / Q000378:metabolism; D009584:Nitrogen / Q000302:isolation & purification*; D010100:Oxygen / Q000378:metabolism; D010758:Phosphorus / Q000302:isolation & purification*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods
D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D012722:Sewage; D010758:Phosphorus; D009584:Nitrogen; D010100:Oxygen