Modelling of Substance Flows in Urban Drainage Systems

Stormwater is recognised as a large contributor of toxic substances to receiving waters. Different measures to manage stormwater quality have been proposed, including structural and non-structural best management practices (BMPs). Computer models have become useful tools for the analysis, evaluation and design of these BMPs. The main objective of this study was to develop a modelling framework that enables an analysis of the pollutant sources in urban drainage systems. In the modelling framework the sources of pollutants from different activities in the urban area were separated according to their origin, e.g. material corrosion, brake wear and tyre wear.The model was named SEWSYS\uae and was developed in MATLAB/Simulink. SEWSYS simulates substance flows in urban drainage systems. At present the model contains 20 different substances, including nutrients, heavy metals and organic pollutants. The model can simulate both stormwater and domestic wastewater flows, in either combined or separate sewer systems. In the stormwater quality module, the pollutants from sources such as atmospheric deposition, traffic and construction materials are generated and accumulated on impervious surfaces during dry weather until they are washed away during rainfall. Validation studies of the SEWSYS model were carried out using measurements of stormwater flow and quality. Calibration and validation were performed using a split-sample technique, i.e. with independent data sets for calibration and validation. The hydrological part of the model performed well in the validation but the quality part produced less reliable results.Uncertainty analysis of the stormwater module in SEWSYS was carried out for the model outputs runoff volume, pollutant concentrations (EMCs and SMC), and pollutant load of heavy metals for an uncalibrated and calibrated model. Uncertainty assessment methods included Monte Carlo simulations, multi-linear regression and a Markov-Chain Monte Carlo method for parameter calibration. The results of the uncertainty analysis showed that predictions made with an uncalibrated model were associated with a considerable amount of uncertainty. It was also shown that by means of calibration this uncertainty could be reduced to an acceptable level.The application of the SEWSYS model in different types of scenario studies has been an important part of the model development. The results from the application studies demonstrate that the model is a useful tool for simulating and evaluating pollutant source control measures

SEWSYS ett verktyg f\uf6r att best\ue4mma k\ue4llor till dagvattenf\uf6roreningar och pr\uf6va olika \ue5tg\ue4rder

Dagvatten transporterar stora m\ue4ngder toxiska \ue4mnen till v\ue5ra vattendrag. En substansfl\uf6desmodell har utvecklatsf\uf6r att m\uf6jligg\uf6ra analys av scenarier relaterade till f\uf6roreningsminskande \ue5tg\ue4rder och k\ue4llkontroll.Datormodellen har f\ue5tt namnet SEWSYS och innefattar generering och transport av f\uf6roreningar i urbanaavrinningsomr\ue5den. F\uf6roreningarnas k\ue4llor \ue4r ocks\ue5 beskrivna i modellen och inkluderar exempelvis materialkorrosion,bromsslitage och d\ue4ckslitage. SEWSYS fr\ue4msta egenskap \ue4r m\uf6jligheten att analysera f\uf6roreningaroch dess m\ue4ngder utifr\ue5n de bidragande k\ue4llorna. F\uf6r n\ue4rvarande hanterar modellen 20 olika substanser sominnefattar n\ue4rings\ue4mnen, metaller och organiska f\uf6roreningar. Det \ue4r m\uf6jligt att simulera b\ue5de dagvatten ochhush\ue5llsspillvatten, antingen i kombinerade eller i duplikata avloppssystem. Modellens m\uf6jligheter demonstrerasi denna artikel genom ett urval av resultat fr\ue5n tv\ue5 till\ue4mpade studier d\ue4r SEWSYS anv\ue4nts f\uf6r substansfl\uf6desmodellering.Baserat p\ue5 den detaljniv\ue5 som modellen har i ber\ue4kningarna av dagvattenf\uf6roreningar ocherfarenheter fr\ue5n flera till\ue4mpade studier har SEWSYS visats sig vara ett anv\ue4ndbart verktyg f\uf6r att simuleradagvattenf\uf6roreningar och utv\ue4rdera \ue5tg\ue4rder som bygger p\ue5 k\ue4llkontroll

Substance flow analysis of the stormwater system in Vasastaden, G\uf6teborg

A substance flow analysis of the stormwater system in Vasastaden in the city of G\uf6teborg has been carried out using a substance flow model called SEWSYS. The model handles fluxes of substances within an urban catchment and keeps track of each substance; where it originates and where it finally ends up. The present sewer system has been studied and the status of sustainability evaluated. Different abatement measures to achieve a system with more sustainability have been modelled and evaluated. The measures include source control and end-of-pipe solutions. From this study it may be concluded that all the studied measures individually lead towards a very high reduction of the discharges of pollution to the water body, but the source control measures are recommended as a first choice since they by definition are sustainable

Modelling substance flows in urban sewer systems using MATLAB/Simulink

A model for simulation of substance flows in urban sewer systems has been developed in the computer programme package MATLAB/Simulink. The model is called SEWSYS and it handles fluxes of substances within an urban catchment. SEWSYS keeps track of each substance; where it originates and where it finally ends up. Some of the substances included are water, phosphorus, nitrogen, heavy metals and PAH. SEWSYS consists of a stormwater module, sanitary wastewater module and a wastewater treatment plant with nitrogen reduction. Verifications have been carried out both for each component separately and for the model as a whole. The results show that the modelling approach is valid, but further enhancements should be made

Modelling substance flows in urban sewer systems using MATLAB/Simulink

A model for simulation of substance flows in urban sewer systems has been developed in the computer programme package MATLAB/Simulink. The model is called SEWSYS and it handles fluxes of substances within an urban catchment. SEWSYS keeps track of each substance; where it originates and where it finally ends up. Some of the substances included are water, phosphorus, nitrogen, heavy metals and PAH. SEWSYS consists of a stormwater module, sanitary wastewater module and a wastewater treatment plant with nitrogen reduction. Verifications have been carried out both for each component separately and for the model as a whole. The results show that the modelling approach is valid, but further enhancements should be made