Open AccessChallenges for simultaneous nitrification, denitrification, and phosphorus removal in microbial aggregates: mass transfer limitation and nitrous oxide production
Author(s) -
Meyer Rikke Louise,
Zeng Raymond Jianxiong,
Giugliano Valerio,
Blackall Linda Louise
Publication year - 2005
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1016/j.femsec.2004.11.011
Subject(s) - denitrification , anoxic waters , nitrification , nitrous oxide , aeration , phosphorus , environmental chemistry , denitrifying bacteria , biomass (ecology) , enhanced biological phosphorus removal , biology , bioreactor , activated sludge , nitrogen , environmental engineering , ecology , chemistry , sewage treatment , environmental science , botany , organic chemistry
The microbial community composition and activity was investigated in aggregates from a lab‐scale bioreactor, in which nitrification, denitrification and phosphorus removal occurred simultaneously. The biomass was highly enriched for polyphosphate accumulating organisms facilitating complete removal of phosphorus from the bulk liquid; however, some inorganic nitrogen still remained at the end of the reactor cycle. This was ascribed to incomplete coupling of nitrification and denitrification causing accumulation. After 2 h of aeration, denitrification was dependent on the activity of nitrifying bacteria facilitating the formation of anoxic zones in the aggregates; hence, denitrification could not occur without simultaneous nitrification towards the end of the reactor cycle. Nitrous oxide was identified as a product of denitrification, when based on stored PHA as carbon source. This observation is of critical importance to the outlook of applying PHA‐driven denitrification in activated sludge processes.