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Combined Anaerobic/Aerobic Digestion: Effect of Aerobic Retention Time on Nitrogen and Solids Removal
Author(s) -
Kim Jongmin,
Novak John T.
Publication year - 2011
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 - 10.2175/106143011x12928814444970
Subject(s) - aerobic digestion , anaerobic exercise , chemistry , volatile suspended solids , kjeldahl method , effluent , anaerobic digestion , pulp and paper industry , wastewater , nitrogen , nitrite , aeration , total dissolved solids , anammox , nitrate , chemical oxygen demand , environmental engineering , denitrification , environmental science , methane , denitrifying bacteria , physiology , organic chemistry , engineering , biology
A combined anaerobic/aerobic sludge digestion system was studied to determine the effect of aerobic solids retention time (SRT) on its solids and nitrogen removal efficiencies. After the anaerobic digester reached steady state, effluent from the anaerobic digester was fed to aerobic digesters that were operated at 2‐ to 5‐day SRTs. The anaerobic system was fed with a mixture of primary and secondary sludge from a local municipal wastewater treatment plant. Both systems were fed once per a day. The aerobic reactor was continuously aerated with ambient air, maintaining dissolved oxygen level at 1.1 ± 0.3 mg/L. At a 4‐day or longer SRT, more than 11% additional volatile solids and 90% or greater ammonia were removed in the aerobic digester, while 32.8 mg‐N/L or more nitrite/nitrate also was measured. Most total Kjeldahl nitrogen removal was via ammonia removal, while little organic nitrogen was removed in the aerobic digester.