Abstract
The Hias process is a novel biofilm based waste water treatment process
designed for phosphorus removal and recovery. The process has also demonstrated
significant nitrogen removal potential. The aim of this study was to investigate
the microbial composition of the Hias biofilm throughout the reactor and how it
relates to its functioning in the process. In addition, the expression of
genes involved in nitrogen removal was evaluated as well as whether their expression
is correlated with chemical components measured in the waste water. A sample
handling method was developed for high quality nucleic acid extraction from
the Hias biofilm. 16S rDNA sequencing revealed microbial composition of the
biofilm to be stable while species evenness decreased throughout the Hias
process. Relative abundance of ammonium oxidising bacteria increased in aerated
parts of the Hias reactor while abundance of phosphate accumulating organisms
decreased. Real time quantitative PCR showed no correlation between
amoA transcript levels and decreasing NH4 concentration.
