Kinetic and microbiological characterization of aerobic granules performing partial nitritation of a low-strength wastewater at 10 °C. (15th September 2016)

• Record Type: Journal Article
• Authors: Reino, Clara; Suárez-Ojeda, María Eugenia; Pérez, Julio; Carrera, Julián
• Is Part Of: Water research. Volume 101(2016)
• Page Start: 147
• Page End: 156
• Publication Date: 2016-09-15
• Subjects: Partial nitritation -- Mainstream -- Low temperature -- NOB-Repression -- AOB-Enrichment -- Anammox; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2016.05.059
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: A granular airlift reactor enriched in ammonia oxidizing bacteria (AOB) was operated at 10 °C performing stable partial nitritation in the long-term. The reactor treated a synthetic low-strength influent during 250 days with an average nitrogen loading rate of 0.63 ± 0.06 g N L −1 d −1 . Nitrate production was barely detected, being the average concentration in the effluent of 0.6 ± 0.3 mg N-NO3 L −1 . Furthermore, a suitable effluent for a subsequent reactor performing the anammox process was achieved. A maximum specific growth rate as high as 0.63 ± 0.05 d −1 was determined by performing kinetic experiments with the granular sludge in a chemostat and fitting the results to the Monod model. Pyrosequencing analysis showed a high enrichment in AOB (41 and 65% of the population were identified as Nitrosomonas genus on day 98 and 233, respectively) and an effective repression of nitrite oxidizing bacteria in the long-term. Pyrosequencing analysis also identified the coexistence of nitrifying bacteria and heterotrophic psychrotolerant microorganisms in the granular sludge. Some psychrotolerant microorganisms are producers of cryoprotective extracellular polymeric substances that could explain the better survival of the whole consortia at cold temperatures. Graphical abstract: Highlights: Long-term partial nitritation was maintained at 10 °C in a granular reactor. High μmax explains high nitrification rates and effective NOB repression. The bacterial diversity in the sludge decreased after long-term operation at 10 °C. Granular sludge was mainly composed by AOB and psychrotolerant microorganisms. Partial nitritation at 10 °C can be operated with low N2 O emissions.