Bioaugmentation with Nitrifying Bacteria Acclimated to Different Temperatures

A nitrifying biomass was produced from anaerobic sludge dewatering liquors for the purpose of bioaugmentation of sequencing batch reactors (SBRs). Nitrification of centrate was conducted at four temperatures (10, 20, 25, and 30°C) while the seeded SBRs were operated at 10°C with a solids retention time of approximately 4 days. The SBRs did not exhibit any nitrification before the onset of seeding. When the hydraulic retention time (HRT) was 24 h, partial removal of NH3-N occurred when seed acclimated to 20, 25, and 30°C was added. When the HRT was 12 h, only the SBR seeded with nitrifying biomass acclimated to 10°C achieved 50% NH3-N removal. Complete removal of NH3-N was not achieved in any of the seeded SBRs. The degree of NH3-N removal in the seeded SBRs was dependent on the initial temperature of the seed, and the observed growth rates of the nitrifying bacteria were inversely proportional to the change in temperature.