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An Investigation of Moving Bed Biofilm Reactor Nitrification during Long‐Term Exposure to Cold Temperatures
Author(s) -
Hoang Valerie,
Delatolla Robert,
Laflamme Edith,
Gadbois Alain
Publication year - 2014
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143013x13807328848694
Subject(s) - nitrification , chemistry , moving bed biofilm reactor , environmental chemistry , wastewater , environmental engineering , ammonia , pulp and paper industry , environmental science , biofilm , nitrogen , engineering , genetics , organic chemistry , biology , bacteria
ABSTRACT: Biological treatment is the most common and economical means of ammonia removal in wastewater; however, nitrification rates can become completely impeded at cold temperatures. Attached growth processes and, specifically, moving bed biofilm reactors (MBBRs) have shown promise with respect to low‐temperature nitrification. In this study, two laboratory MBBRs were used to investigate MBBR nitrification rates at 20, 5, and 1 °C. Furthermore, the solids detached by the MBBR reactors were investigated and Arrhenius temperature correction models used to predict nitrification rates after long‐term low‐temperature exposure was evaluated. The nitrification rate at 5 °C was 66 ± 3.9% and 64 ± 3.7% compared to the rate measured at 20 °C for reactors 1 and 2, respectively. The nitrification rates at 1 °C over a 4‐month exposure period compared to the rate at 20 °C were 18.7 ± 5.5% and 15.7 ± 4.7% for the two reactors. The quantity of solids detached from the MBBR biocarriers was low and the mass of biofilm per carrier did not vary significantly at 20 °C compared to that after long‐term exposure at 1 °C. Lastly, a temperature correction model based on exposure time to cold temperatures showed a strong correlation to the calculated ammonia removal rates relative to 20 °C following a gradual acclimatization period to cold temperatures.