Nitrifying biofilm development with time: activity versus phylogenetic composition.
The development of nitrifying biofilms collected from a full-scale nitrifying trickling filter was evaluated through the application of fluorescent in situ hybridization (FISH) and by quantification of nitrification rates in bench-scale reactors. Two sampling campaigns were conducted to evaluate the structure and function of biofilms between 14 and 70 days old. The structure, or number of ammonia-oxidizing bacteria, was quantified with Nso190. The function was quantified with bench-scale nitrification rates. The two assays were compared by calculating correlation coefficients by simple linear regression of the two data sets. The number of ammonia-oxidizing bacteria closely tracked activity data (linear correlation, r2 > 0.500). Changes in ammonia-oxidation capacity with time (7-day intervals) were mirrored by shifts in the percent of ammonia-oxidizing bacteria present. Nitrification rates did not correlate to the EUB338-probe stained area (r2 < 0.500), suggesting that nonnitrifying bacteria play a larger role in nitrifying biofilm ecology than previously thought. Dry-weight biomass accumulations did not correlate to either the EUB338-probe stained area or the bench-scale nitrification rates. This suggests that inert materials accumulate in the biofilms over time.
Biesterfeld
Sidney
S
Environmental Science and Engineering, Colorado School of Mines, Golden, USA. scb@rtweng.com
Figueroa
Linda
L
D000641:Ammonia / Q000378:metabolism; D001419:Bacteria; D018441:Biofilms; D018533:Biomass; D019149:Bioreactors; D005374:Filtration; D017404:In Situ Hybridization, Fluorescence; D009584:Nitrogen / Q000378:metabolism*; D010802:Phylogeny; D011157:Population Dynamics; D014865:Waste Disposal, Fluid
D000641:Ammonia; D009584:Nitrogen