Keywords
climate change, integrated modelling, risk, uncertainty, optimisation, urbanisation, wastewater system, water quality
Start Date
1-7-2012 12:00 AM
Abstract
Climate change and urbanisation are key factors potentially affecting thefuture of water quality and quantity in urbanised catchments and are associatedwith significant degrees of uncertainty. Maintaining or even improving urbanrecipient water quality under this uncertain future will be a major challenge. Thestudy reported in this paper explores the potential for managing water quality withina novel risk-based framework in the context of an Integrated Urban WastewaterSystem (IUWS) comprised of a sewer system, wastewater treatment plant and therecipient. In the study, we explore the potential for managing water quality failurerisk by optimising the operational control and/or design of the wastewater system.Water quality failure risk is defined as the product of the likelihood and impact ofwater quality standard breaches. The optimisation objectives are the minimisationof water quality failure risk in terms of both dissolved oxygen and ammoniaconcentrations. The decision variables are a set of IUWS operational control anddesign parameters. The above optimisation problem was solved using the modifiedMOGA-ANN method. The results obtained from a semi-hypothetical case-studyundergoing urbanisation and subject to climate change indicate that operationalcontrol optimisation has the potential to reduce the risk of recipient water qualityfailure but, in this particular case, cannot fully meet appropriate water qualitystandards. It was found that an acceptable level of risk can only be achieved bycombining improved operational control and system (re)design.
Risk-based Water Quality Management in an Integrated Urban Wastewater System under Climate Change and Urbanisation
Climate change and urbanisation are key factors potentially affecting thefuture of water quality and quantity in urbanised catchments and are associatedwith significant degrees of uncertainty. Maintaining or even improving urbanrecipient water quality under this uncertain future will be a major challenge. Thestudy reported in this paper explores the potential for managing water quality withina novel risk-based framework in the context of an Integrated Urban WastewaterSystem (IUWS) comprised of a sewer system, wastewater treatment plant and therecipient. In the study, we explore the potential for managing water quality failurerisk by optimising the operational control and/or design of the wastewater system.Water quality failure risk is defined as the product of the likelihood and impact ofwater quality standard breaches. The optimisation objectives are the minimisationof water quality failure risk in terms of both dissolved oxygen and ammoniaconcentrations. The decision variables are a set of IUWS operational control anddesign parameters. The above optimisation problem was solved using the modifiedMOGA-ANN method. The results obtained from a semi-hypothetical case-studyundergoing urbanisation and subject to climate change indicate that operationalcontrol optimisation has the potential to reduce the risk of recipient water qualityfailure but, in this particular case, cannot fully meet appropriate water qualitystandards. It was found that an acceptable level of risk can only be achieved bycombining improved operational control and system (re)design.
