Development of simulation system to combine production process and wastewater treatment: calibration of bleached kraft process model through dissolved organic matter in fibreline

Simulation models for bleached kraft and activated sludge processes are being developed to be used simultaneously for integrated pollution prevention and control (IPPC). In this paper, only the simulation model (modified PROCELL) calibration for bleached kraft process is discussed. The simulation model was calibrated with dissolved organic matter (DOM) using dissolved volatile solids (DVS) values and operational information of a mill. Calibrated DOM in carryover and filtrate throughout the fibreline differed by 10% or less from the measured values in the mill. Complete degradation of DOM to inorganics within the production process is required to make the organic matter balance complete. In the calibrated fibreline, complete degradation of DOM proved to be of the same magnitude as the DOM load from bleaching filtrates (D₀ and E₁). Complete balance evaluation facilitates the control of the fate of DOM. Data analyzing procedure was developed to determine the basic structure of the DOM (C_aH_bON_c). The information of conventional analyses of DOM such as organic carbon (DOC), DVS and chemical oxygen demand (DCOD_Cr) was developed to elucidate the basic structure of DOM. The degree of oxidation is one feature derived from the structure of DOM. The degree of oxidation seemed to be less in the filtrate than in the carryover in the alkaline stages, while the reverse was occurred in the acid stages.