1. Combined anaerobic and aerobic digestion for increased solids reduction and nitrogen removal
- Author
-
Novak, John T., Banjade, Sarita, and Murthy, Sudhir N.
- Subjects
- *
ANAEROBIC digestion , *NITROGEN removal (Water purification) , *WASTE recycling , *WATER reuse , *THICKENING of sewage sludge , *TOTAL Kjeldahl nitrogen , *SEWAGE sludge digestion , *WATER pollution - Abstract
Abstract: A unique sludge digestion system consisting of anaerobic digestion followed by aerobic digestion and then a recycle step where thickened sludge from the aerobic digester was recirculated back to the anaerobic unit was studied to determine the impact on volatile solids (VS) reduction and nitrogen removal. It was found that the combined anaerobic/aerobic/anaerobic (ANA/AER/ANA) system provided 70% VS reduction compared to 50% for conventional mesophilic anaerobic digestion with a 20 day SRT and 62% for combined anaerobic/aerobic (ANA/AER) digestion with a 15 day anaerobic and a 5 day aerobic SRT. Total Kjeldahl nitrogen (TKN) removal for the ANA/AER/ANA system was 70% for sludge wasted from the aerobic unit and 43.7% when wasted from the anaerobic unit. TKN removal was 64.5% for the ANA/AER system. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF