engleski

Parameter sensitivity analysis of activated sludge models for wastewater treatment

Sensitivities of kinetic parameters of activated sludge models were analyzed using global sensitivity analysis according to Fourier Amplitude Sensitivity Test (FAST) in order to define the most important parameters of each model and to perform comparison among each other. ASM models were developed for better control of the wastewater treatment process and modification of biological nutrient removal. The proposed models present world standard for numerical modelling of an activated sludge system. ASM1 (Henze et al., 1987) and ASM3 (Gujer et al., 1999) models describe only the removal of COD and nitrogen which are divided into fractions, presented by the state variable. Whereas in ASM1 all state variables are directly influenced by change in a parameter value, in ASM3 that influence is considerably lower, allowing a better identification. ASM2d (Henze et al., 1999) is a further development of ASM2 (Henze et al., 1995) with the addition of denitrifying activity of Phosphorus Accumulating Organisms (PAOs) which should allow a better description of phosphate and nitrate dynamic. The ASM2d classifies biomass into three groups (ordinary heterotrophs, nitrifiers and PAOs). COD components in the model are classified as soluble and particulate. The soluble COD components are either inert or biodegradable. Application of the FAST algorithm provides sensitivity to large and simultaneous changes of the complete set of the model parameters. Results of the FAST analysis have application in identification of metabolic regulation and potentially elucidate the main effect in enzyme regulation. The obtained results indicate that the output variable (the concentration of biodegradable substrates at a steady state) in all three analysed models is most sensitive on hydrolysis rate constant.

wastewater treatment ; activated sludge model ; global sensitivity analysis ; FAST

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