Effects of porous carrier size on biofilm development, microbial distribution and nitrogen removal in microaerobic bioreactors

Muhammad Ahmad, Sitong Liu, Nasir Mahmood, Asif Mahmood, Muhammad Ali, Maosheng Zheng, Jinren Ni

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


In this study, effects of porous carrier’s size (polyurethane-based) on microbial characteristics were systematically investigated in addition to nitrogen removal performance in six microaerobic bioreactors. Among different sized carriers (50, 30, 20, 15,10, 5 mm), 15 mm carrier showed highest nitrogen removal (98%) due to optimal micro-environments created for aerobic nitrifiers in outer layer (0∼7 mm), nitrifiers and denitrifiers in middle layer (7∼10 mm) and anaerobic denitrifiers in inner layer (10∼15 mm). Candidatus brocadia, a dominant anammox bacteria, was solely concentrated close to centroid (0∼70 μm) and strongly co-aggregated with other bacterial communities in the middle layer of the carrier. Contrarily, carriers with a smaller (15 mm) either destroy the effective zone for anaerobic denitrifiers or damage the microaerobic environments due to poor mass transfer. This study is of particular use for optimal design of carriers in enhancing simultaneous nitrification-denitrification in microaerobic wastewater treatment processes.
Original languageEnglish (US)
Pages (from-to)360-369
Number of pages10
JournalBioresource Technology
StatePublished - Mar 15 2017

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