Granulation of Anammox microorganisms in up-flow reactors

• Published in: Water Science & Technology Vol. 49; no. 5-6; pp. 155 - 163
• Main Authors: Imajo, U, Tokutomi, T, Furukawa, K
• Format: Journal Article Conference Proceeding
• Language: English
• Published: England IWA Publishing 01.01.2004
• Subjects: Biological Wastewater Treatment; Biomass; Bioreactors; Feasibility studies; Granular materials; Granulation; Microorganisms; Nitrates; Nitrites; Nitrogen - isolation & purification; Nitrogen - metabolism; Nitrogen removal; Oxidation-Reduction; Particle Size; Physical properties; Population Dynamics; Quaternary Ammonium Compounds - chemistry; Reactors; Removal; Sewage - chemistry; Sewage - microbiology; Sludge; Sludge digestion; Waste Disposal, Fluid - methods
• ISBN: 9781843394624; 1843394626
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2004.0749

Experimental studies were performed to evaluate the feasibility of granulation of Anammox microorganisms for biomass retention in up-flow reactors. Two experimental studies, one using a 6.4-L lab-scale reactor with synthetic medium and the other using a 200-L pilot-scale reactor with half-nitrified reject water from a sludge digester were conducted. To enhance the granulation process, seed granules from a UASB reactor were added to both experimental reactors. Granulation of Anammox microorganisms was observed using both the synthetic medium and the reject water. The core of a large proportion of Anammox granules retained part of the original seed biomass. The Anammox granules had a slightly lower density than the seed granules from the UASB process, but the size and other physical properties were comparable. The successful granulation of the Anammox microorganisms led to a stable nitrogen removal performance. The maximum nitrogen removal rate of the lab-scale reactor was observed to be 2.9 kg/(m3 x d) after 173 days of operation and that of the pilot-scale reactor was 6.4 kg/(m3 x d) after 12 months of operation.