Start-up of the Anammox process in a membrane bioreactor

• Published in: Journal of biotechnology 2006-12, Vol.126 (4), p.475-487
• Main Authors: Trigo, C., Campos, J.L., Garrido, J.M., Méndez, R.
• Format: Article
• Language: English
• Subjects: Ammonia - metabolism; Anammox; Bacteria, Anaerobic - metabolism; Biological and medical sciences; Biomass; Bioreactors - microbiology; Biotechnology; Denitrification; Fundamental and applied biological sciences. Psychology; Granule; Membrane; Membranes; Microscopy, Electron, Scanning; MSBR; Nitrites - metabolism; Nitrogen - isolation & purification; Nitrogen - metabolism; Oxidation-Reduction; Time Factors; Waste Disposal, Fluid - methods; Wastewater; Water Purification - instrumentation; Water Purification - methods
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2006.05.008

The start-up of an Anammox process was studied in a membrane sequencing batch reactor (MSBR) in which a submerged hollow fibre membrane module was used to retain the biomass. The reactor was seed with Anammox biomass and fed using the Van de Graaf medium. During a first operating stage, salt precipitation was observed and interfered with microbial activity and caused a decrease of the nitrogen removal rate of the reactor from 100 to only 10 mg l −1 per day. Salt precipitation was avoided by diminishing adequately the Ca and P concentrations of the Van de Graaf medium during the last operating stage. This action increased quickly the activity of the system, and nitrogen removal rate reached up to 710 mg l −1 per day with almost full nitrite removal. Sporadic flotation of the sludge was observed in the MSBR. The use of the membrane avoided biomass wash-out from the system. Moreover, a surprising fact was that Anammox biomass did not grow in flocs in the MSBR, but in granules. This fact showed that this kind of microorganisms have a trend to grow in aggregates. Results indicated that the use of the MSBR could be a suitable system for nitrogen removal by using the Anammox reaction.