Models for ecosystem-based wastewater management
The new Water Framework Directive (WFD) policy demands integrated management of the rivers, sewer systems and wastewater treatment plants (WWTPs) of an urban water system. Without integrated management, resources are misused, freshwater ecosystems are degraded and the overall costs of wastewater treatment increase. The EU-funded ECOMAWAT (Ecosystem-based management strategies for urban wastewater systems) initiative investigated the integrated management of urban wastewater systems and freshwater ecosystems, aiming to reduce environmental impact while minimising the costs of wastewater treatment. Researchers collected data on how WWTPs and freshwater ecosystems process traditional (organic matter and nutrients) and emerging effluents (e.g. pharmaceuticals). They found that WWTPs removed pharmaceutical pollution in larger volumes than rivers, but that the rivers were more efficient in that removal. ECOMAWAT designed and patented a low-cost sensor to monitor sewer overflow into rivers during wet weather. This sensor could be widely used to help calibrate hydrodynamic models of sewer systems. Project members also developed inventories of resources required for the construction and operation of sewers and WWTPs, which can be used for life-cycle assessments. Finally, using data they had collected during the project, researchers built a model coupling a WWTP to a river to understand how contaminants are distributed. This can be used to see how changing the operating conditions of a WWTP affects the attenuation of contaminants. The work of ECOMAWAT has provided the most detailed model yet of the interaction between rivers and WWTPs. This resource will be useful in almost any urban water management scenario in Europe and the rest of the world.
Keywords
Wastewater, freshwater ecosystems, rivers, sewer systems, ECOMAWAT, contaminants