Biofilms for One-stage Autotrophic Nitrogen Removal
Jose M Carvajal-Arroyo, Tiago Rogeiro Vitor Akaboci, Maël Ruscalleda, Jesus Colprim, Emilie Courtens and Siegfried E. Vlaeminck
from: Aquatic Biofilms: Ecology, Water Quality and Wastewater Treatment (Edited by: Anna M. Romaní, Helena Guasch and M. Dolors Balaguer). Caister Academic Press, U.K. (2016) Pages: 205-222.
About 20 years after the discovery of microbial anoxic ammonium oxidation (anammox), the autotrophic nitrogen removal through partial nitritation-anammox (PNA) for ammoniacal wastewater treatment has become a mature technology. The application of these slow growing anoxic ammonium-oxidizing bacteria (AnAOB) requires engineered systems with efficient biomass retention. In the last decade, several one-stage PNA technologies have been developed that promote the growth of AnAOB in biofilms along with aerobic ammonium-oxidizing bacteria (AerAOB). Such biofilms grow on the surface of a carrier material or in mm-scale bio-aggregates (granules). Thanks to the easy retention of biofilm carriers or good settleability of granules, long sludge retention times can be maintained. Additionally, diffusional oxygen transfer limitation within the biofilm allows for the creation of aerobic and anoxic microniches where AerAOB and AnAOB, respectively, can thrive. This chapter describes and discusses the engineering and ecological characteristics of the different technologies developed so far, including rotating biological contactors (RBC), moving bed biofilm reactors (MBBR), membrane-aerated biofilm reactors (MABR) and granular systems. Moreover, the recent literature on operation parameters that influence the greenhouse gas emissions (i.e., N2O) during PNA are described . Finally the future trends in the biofilm-PNA applications to new effluents, with special attention to mainstream sewage treatment, are discussed read more ...