MULTIVARIATE TIME-SERIES ANALYSIS FOR DESIGN AND OPERATION OF A BIOLOGICAL WASTE-WATER TREATMENT-PLANT

In the area of biological wastewater treatment, the more common approa ch to dynamical modelling has been the use of mechanistic models with differential equations. This study illustrates that multivariate time series analysis can he a valid alternative. A lab-scale activated slud ge unit, treating brewery wastewater, was operated with a highly varia ble GOD-load. For design and operation purposes, we wanted to model th e behaviour of biomass and effluent-quality. Because of the dynamic na ture of the system, it was not possible to use steady-state relations. With time series analysis, we succeeded in modelling the dynamic beha viour, using only daily routine measurements. Simple equations, descri bing biomass, effluent COD and effluent suspended solids are obtained and combined to form one system of difference equations. The use of th is system is basically equivalent to the use of models consisting of d ifferential equations. Thus by means of simulations, design and operat ion alternatives can be evaluated. (C) 1998 Elsevier Science Ltd. All rights reserved.