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Modeling and Simulation of Activated Sludge Process with Cyclic Feeding for Treatment of Highly Loaded Wastewater
Author(s) -
CharmotCharbonnel MarieLouise,
Ripoche Gilles,
Roche Nicolas,
Prost Christian
Publication year - 1999
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/(sici)1521-4125(199901)22:1<50::aid-ceat50>3.0.co;2-4
Subject(s) - clarifier , activated sludge , aeration , effluent , biomass (ecology) , wastewater , sewage treatment , extracellular polymeric substance , pulp and paper industry , chemistry , environmental engineering , hydraulic retention time , environmental science , agronomy , engineering , biology , bacteria , biofilm , genetics , organic chemistry
The treatment of strongly loaded wastewater (COD > 1,5 kg m –3 by an activated sludge process (aeration basin + clarifier) depends both on the ability of the activated sludge to remove the soluble organic pollution and on the efficiency of the separation of the treated water from the biomass. The separation ability of the activated sludge notably depends on the hydraulic configuration of the aeration basin: biomass settleability can be controlled by completely mixed reactors (CMR) in series, plug‐flow reactors or intermittently fed systems. Moreover, the biomass settleability is linked to the extracellular polymers which are largely composed of microbial exopolysaccharides (EPS). A low level of EPSs indicates a sludge deflocculation problem, whereas a high level of EPSs means that sludge settleability could be hindered because of an excessive growth of filamentous organisms. Experiments show that the use of only one CMR, fed in a cyclic way with permanent oxygenation and return sludge flow, leads to good settleability and effluent quality. The purpose of this paper is to propose a very simple model, based on experiments, in order to optimize the cyclic feeding period by simulations.