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Reuse of Air for Return Activated Sludge Pumping in Submerged Membrane Bioreactors
Author(s) -
Starke Christina,
Bérubé Pierre R.
Publication year - 2016
Publication title -
chemie ingenieur technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.365
H-Index - 36
eISSN - 1522-2640
pISSN - 0009-286X
DOI - 10.1002/cite.201500080
Subject(s) - airlift , sparging , reuse , bioreactor , activated sludge , membrane bioreactor , environmental science , environmental engineering , waste management , process engineering , engineering , chemistry , sewage treatment , organic chemistry
Abstract The reuse of air added for gas sparging to airlift return activated sludge (RAS) in a membrane bioreactor (MBR) was investigated. Numerical modeling suggests that the RAS conveyance requirements in an MBR could be met for systems with a treatment capacity of ≤3.8 · 10 6 L d −1 , and potentially for larger MBRs, depending on the system design (i.e., U‐shaped rather than linear systems). Pilot scale validation confirmed that airlift could be used to meet the RAS conveyance requirements. Optimal conditions were obtained for pilot scale systems with square air collectors, intermediate/large air collector angles, greater depth of submergence and individual tubing to redirect the airlifted flow. Implementation of airlift RAS conveyance in small to intermediate size MBRs can results in a reduction of approximately 20 % in operating costs.