Sustainable Wastewater Management—A Definition and Criteria for Assessment

Addressing sustainable wastewater management is not new; sustainability and wastewater are discussed so frequently together that the concept may feel overused. It is therefore surprising that such a widely used term as sustainable wastewater management does not have a clear, widely accepted definition. We argue that this hinders progress towards sustainability and might even lead to unsustainable decisions. Here, we propose a definition of sustainable wastewater management, applicable to both existing and planned wastewater systems and grounded in established and well accepted definitions of sustainable development, such as the United Nations Sustainable Development Goals. We present a set of objectives that frame and define sustainable wastewater management. The objectives cover the areas recipient protection, nutrient recovery, biodiversity, substances of emerging concern, climate change, energy and resource use, water reuse, collaboration, social aspects including fairness, and economy. We discuss what these areas entail and potential conflicts and trade-offs that must be handled. To support decision makers, we suggest criteria intended for use in multicriteria sustainability assessments. The criteria are linked to the objectives defining sustainable wastewater management. Both the definition and the associated criteria set presented here can support the wastewater sector in progressing towards sustainability.