A systems analysis of N2O production risks in municipal wastewater treatment across all treatment technologies: PAPER & PRESENTATION
Stephen Palmer, Technical Director, Stantec, UK
(free)
The metagenomics of the municipal wastewater treatment is in the first instance driven by wastewater selection pressures which is why a core group of prokaryotes retain a presence in different bioreactor systems, across the range of technologies available (from biofilm reactors to suspended growth activated sludge to granular biomass reactors).
The dominating prokaryotes in municipal wastewater treatment utilise quorum sensing to optimise efficient use of resources and avoid washout. The heterotrophic bacteria in this group provide the phenotype for physical ‘form’ for treatment biomass, with other functionality being provided by microecological niche occupiers including autotrophic nitrifiers. Within that heterotrophic prokaryote community denitrification is a common resource diversification trait. In this group carbon limitation and other forms of anoxic growth limitation are the principal drivers of N2O emission during denitrification. In the niche bipartite (ammonia oxidising prokaryote (AOP) and nitrite oxidising prokaryote (NOP)) nitrifying community, environmental factors that desynchronise the activity of these two groups lead to increased N2O production.
