Activated sludge dynamics

The paper is organized as follows. A brief review of the activated sludge dynamics and DO control is made. Then the properties of DO profiles in organic removal are discussed. In the last section it is shown, that the DO profile concept can be favourably used in reactors with combined organic and nitrogen removal, and the implications for control are discussed. 

Oxygen balance for an aerated system with activated sludge is defined by a dynamic model ... 

DYNAMIC MODEL AND OXYGEN TRANSFER RATE IN ACTIVATED SLUDGE... 

Martinez M, Rodriguez-Roda 1, Poch M, Cortes U, Comas J (2006) Dynamic reasoning to solve complex problems in activated sludge processes a step further in decision support systems. Water Sci Technol 53(1) 191-198... 

Watanabe K, S Yamamoto, S Hino, S Harayama (1998a) Population dynamics of phenol-degrading bacteria in activated sludge determined by gyrB-targeted quantitative PGR. Appl Environ Microbiol 64 1203-1209. 

Ekama, G.A. and G. v. R. Marais (1978), The dynamic behaviour of the activated sludge process, Research report No. W 27, Department of Civil Engineering, University of Cape Town. 

Alexander, M. (1994). Biodegradation and Bioremediation. New York Academic Press. Allsop, P.J., Moo-Young, M. Sullivan, G. R. (1990). The dynamics and control of substrate inhibition in activated sludge. Critical Reviews in Environmental Control, 20, 115-67. 

The activated sludge process is recognized as the most common and major unit process for the reduction of municipal and industrial waste. Although its dynamics is complex the potential for control is far from exhausted. Already with commercially available instrumentation today its operation can be significantly improved. 

DO dynamics and control is of vital importance for the operation of an activated sludge system. The relation between DO and biological activity will be summarized here. 

M. Yong, P. Yongzhen, U. Jeppsson, 2006, Dynamic evaluation of integrated control strategies for enhanced nitrogen removal in activated sludge process, Contrl. Eng. Prac., 14, 1269-1278. 

Kaewpipat, K., Grady, J. C. P. L. (2002). Microbial population dynamics in laboratory-scale activated sludge reactors. Water Science Technology, 46(1-2), 19-27. 

SBR is a biological method, which is an activated sludge wastewater treatment technology under intermittent aeration. Different from the traditional wastewater treatment process, the operation mode of space partitioning was placed by time division technology, steady-state biochemical reactions was placed by non-stable alternative technology the traditional dynamic precipitation... 

Abstract Polyhydroxyalkanoates (PHA) are intracellular polymers stored by many bacterial species. Presently PHA arc industrially produced by pure cultures fermentation where high quality substrates are used. Mixed cultures using raw substrates are able to produce PHA when submitted to transient conditions like oscillations on substrate feeding or on oxygen supply. The yield on PHA produced by activated sludge submitted to these dynamic conditions reach values comparable to those obtained by the pure cultures, being the first process less cost intensive than die last one. The chain length of the polymer produced in both processes is similar. 

Majone, M., Dircks, K. and Beun, J. J., 1999, Aerobic storage under dynamic conditions in activated sludge processes. The state of the art. Wat. ScL Technol, 39 61-73. 

Bacterial Poly(3 hydroxybutyrate-co-3 Dynamic mechanical Activated sludge [115]... 

The use of DAF for dynamic activated sludge thickening has only recently become common. It allows concentrations of 40 to 70 g r under direct pressurization at a mass load four to five times higher (120 to 180 kg of DS per m -d ) than by gravity settling. 

The behavior of activated sludge systems has been best described in various papers of Andrews (18,25). A number of other persons have attempted to do dynamic analyses of waste treatment systems. For the most part, none of the analyses are completely satisfactory. 

Karama, A B, Onyejekwe, O. O, Brouckaert, C. J, Buckley, C. A. (1999), The use of Computational Fluid Dynamics (CFD). Technique for evaluating the efficiency of an activated sludge reactor . Water Science and Technology, 39 329-332. 

Moreno J.L., Hernandez T., Garcia C. Effect of a cadmium-contaminated sewage sludge compost on dynamics of organic matter and microbial activity in an arid soil. Bio Ferti Soils 1999 28 230-237. 

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