Contribution of Modelling to Enhancing the Operation of Wastewater Treatment Plants: Case Study of Maghnia and Tlemcen WWTPs

Abstract

Mathematical modelling of activated sludge systems has become a widely accepted tool and is used in particular for optimization and upgrading of existing plants and for new facilities design, either by engineering and consulting companies, or university and research centres. The adopted methodology in this study is based on numerical simulations conducted by the ASM1 model (Activated Sludge Model No. 1), which incorporates the kinetics of organic and nitrogen removal processes in association of the GPS-X simulator in order to obtain an optimal solution for treatment performances. Two treatment facilities were examined: the Maghnia wastewater treatment plant (MWWTP) and Tlemcen City’s plant (Ain Elhoutz TWWTP), Data collection from these plants, coupled with statistical analysis of input and output quality, facilitated the completion of this study, allowing for a comprehensive evaluation of their performance. After a successful steady state calibration of three effluent state variables (observed concentration values of chemical oxygen demand (COD), total suspended solids (TSS), and ammonium (NH4-N) parameters), the Maghnia WWTP ASM1 modelling yielded promising outcomes in predicting COD removal performance under dynamic conditions with some reservations regarding TSS, and NH4-N. The second case study focused on assessing the dynamism of Chemical Oxygen Demand (COD) effluent quality, viewing it as a pivotal measure of plant performance. The application of ASM1 model in Ain Elhoutz TWWTP was guided by a sensitivity analysis approach and an optimization for dynamic calibration of the model. The results of model validation indicate that the calibration was performed properly with a good correlation coefficient (R²). The ASM1 model effectively reflects the dynamic fluctuations in COD effluent concentrations for both plants, the modelling of wastewater treatment plants (WWTPs) presented in this thesis represents a significant step forward in a relatively new field.