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Novel Stokesian Metrics that Quantify Collision Efficiency, Floc Strength, and Discrete Settling Behavior
Author(s) -
MancellEgala William A.S.K.,
De Clippeleir Haydee,
Su Chungyung,
Takacs Imre,
Novak John T.,
Murthy Sudhir N.
Publication year - 2017
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 - 10.2175/106143017x14902968254494
Subject(s) - settling , flocculation , biological system , collision , settling time , exponential function , sedimentation , environmental science , materials science , mechanics , environmental engineering , mathematics , computer science , physics , engineering , mathematical analysis , geology , paleontology , computer security , control engineering , sediment , step response , biology
Novel parameters were developed to predict the effluent quality and settling behavior in clarifiers that cannot conventionally be achieved using either the conventional flux theory or overflow rates. Simple batch experiments based on the critical settling velocity (CSV) selection were used as the basis for the development of three novel parameters: intrinsic settling classes (ISC), threshold of flocculation/flocculation limitation (TOF/α), and floc strength. ISC was proven to accurately (±2%) determine the granule fraction and discrete particle distribution. TOF quantified the minimum solids concentration needed to form large flocs and was directly linked to collision efficiency. In hybrid systems, an exponential fitting on a CSV matrix was proposed to quantify the collision efficiency of flocs (α). Shear studies were conducted to quantify floc strength. The methods were applied to a wide spectrum of sludge types to show the broad applicability and sensitivity of the novel methods.