Study on anammox of low concentration of ammonia nitrogen wastewater in ABR

Key words: 
• anammox /
• ABR /
• ammonia nitrogen /
• nitrite nitrogen

Abstract: Anaerobic ammonium oxidation (anammox) process was start-up in a anaerobic baffled reactor(ABR) inoculated with anaerobic sludge and river sludge under low ammonia concentrations. The water quality of effluent was stepwise reachered to a stable level after 4 months’ enrichment operation. The average removal efficiencies of NH3-N and NO–2-N were 85.7％ and 98.8％ when the volume loading rate was 3.91 g/(m3·d) and 3.21 g/(m3·d) respectively. The anaerobic sludge in ABR was analyzed by fluorescence in situ hybridization (FISH). Then the loading rate of this ABR system was increased gradually by shortening the HRT or by increasing NH3-N and NO–2-N concentrations in the influent. Finally, when the volume loading rate of NH3-N and NO–2-N were 65.53 g/(m3·d) and 68.46 g/(m3·d), the average removal efficiencies reached 76.3％and 91.3％, respectively. Sludge granules with the diameter of 1.7～2.5 mm were developed. The enriched granular sludge and the initial seed granular sludge were obseverd by scan electronic microscope(SEM), the microorganism species in the enriched granular sludge with high anammox activity became much simplified comparing to those of the initial seed granule.