Nitrogen Removal Performance of Novel HABR Reactor over CANON Process

Abstract

The startup of novel hybrid anaerobic baffled reactor (HABR) and the feasibility of completely autotrophic nitrogen removal over nitrite (CANON) process were studied. The reactor was operated by gradually decreasing HRT to improve total nitrogen load. After startup, the change of nitrogen concentrations, conductivity, pH and MLSS was measured along the reactor, and then the microbial morphology and spatial structure of bacteria were defined. The test results indicated several points:under the experimental condition of an average NH4+-N of 40 mg·L-1 in influent, the quick start-up process was successfully achieved by continuous operation within 89 days, and stabilized over 187 days. The average NH4+-N and TN concentrations of effluent were below 2 mg·L-1 and 10 mg·L-1 respectively, the average removal efficiencies of NH4+-N and TN reached above 96% and 83% respectively, and a NRR of 0.15 kg·(m3·d)-1 was obtained. During the stable phase, the concentrations of NH4+-N and TN gradually declined along the reactor, while the concentrations of NO2--N and NO3--N remained constant at relatively lower values. The highest nitrogen removal efficiency of ammonia occurred in compartment 1, and the reason was confirmed by SEM and FISH microbiological analysis that enriched functional bacteria of AOB and AnAOB coexisted in compartment 1.