Deploying innovative wastewater management, treatment and valorisation solutions in European cities and regions in the context of climate change

Expected Outcome:

Projects are expected to contribute to all of the following outcomes:

• Cities and regions are equipped with innovative practices for urban wastewater management, adapted to climate change, taking into account: energy efficiency, energy and secondary raw material recovery and water reuse, including opportunities for renewable energy generation and secondary resource production, implemented at city and regional level.

• Treatment infrastructures and management solutions are deployed and upscaled for water, storm water and wastewater in cities and regions, with positive effects on climate adaptation, biodiversity, air and water pollution reduction, resource valorisation and energy efficiency.

• Knowledge is disseminated about innovative practices, governance and business models for integrated (waste)water management, in the context of climate change among relevant stakeholder groups to facilitate effective replication and upscaling.

• Actionable insights are developed to support European cities and regions in addressing the main administrative, governance and financing barriers for rain- and waste-water management, recovery of resources (secondary raw materials, water and energy) and their (market) valorisation.

Scope:

This topic supports the implementation of the EU Mission Climate-Neutral Smart Cities, EU Mission on Adaptation to Climate Change as well as the EU Circular Cities and Regions Initiative (CCRI). It aims to support the water sector in European cities and regions in accelerating their climate neutral, climate resilient and circular transition.

The recast EU Urban Wastewater Treatment Directive[1] introduces new requirements on energy neutrality at national level for urban wastewater treatment plants treating population equivalents of over 10,000 (UWWTPs). It also requires management plans for stormwater overflows, and consideration of circular economy measures to stimulate the reuse of nitrogen, phosphorus and water.

Wastewater infrastructure investment is a significant expense and generally addresses only the collection and treatment aspects. To make the most of such investments, adopting a holistic and integrated approach is vital. By combining insights from land use, wastewater characteristics, and sewer system knowledge, we can better manage rain run-off during extreme weather, optimize the recovery of resources such as secondary raw materials, water, and energy, and prevent pollution incidents related to stormwater overflows. Furthermore, incorporating a regional approach might allow smaller wastewater utilities to share resources more effectively.

To address these needs, proposals are required to develop integrated approaches to address at least three of the following aspects:

• Demonstrate nature-based solutions e.g. vegetated ditches, treatment wetlands and storage ponds designed to support biodiversity and favour infiltration and where possible to harvest rainwater for reuse at city and regional level, while addressing the effects of climate change.

• Implement sustainable urban drainage principles and green-blue storm water management solutions to avoid and reduce pollution from rain and storm water, including during extreme weather events.

• Implement energy efficiency and recovery measures and technologies from sewers and/or one or multiple UWWTPs to reduce greenhouse gas and air pollutant emissions by pooling resources; this can include renewable energy from solar energy production, waste heat recovery or biogas production from sludge.

• Explore the pooling of resources at regional level to rationalise investment in resource recovery technologies and address the associated regulatory barriers through local end-of-waste criteria.

All projects should address all of the following aspects:

• incorporate solutions for the reuse of (waste)water, addressing the increased pressures on the availability of water resources.

• conceptualise, implement and test possible combinations of urban wastewater treatment, valorisation and reuse processes in selected European cities and regions (referred to as “demonstrators”).

• identify the enabling conditions, e.g. legislative, regulatory, policy, governance, financing, that support the deployment of these tested solutions in other European cities and regions (the “replicators”).

• develop actionable insights that European cities and regions can use to overcome barriers to wastewater reuse and valorisation, and allow further replication and upscaling.

Each project funded under this topic must involve entities from at least four cities or regions, each from a different Member State or Associated Country, with on-the-ground testing in at least two demonstrator cities/regions, and engagement with at least two replicator cities/regions to identify enabling conditions for wider deployment. In the participating cities or regions the local water management organisation should be part of the consortium. At least one entity in each project must be from one of the 112 cities selected for the EU Mission on Climate-neutral and Smart Cities[2] and at least one must be from a signatory to the Adaptation Mission Charter [3].

Projects are encouraged to engage in clustering activities with other relevant Horizon Europe projects that share a common theme and address similar issues, and/or are connected to the Climate Neutral and Smart Cities and Climate Adaptation Missions as well as the CCRI. To this end, proposals should include a dedicated task, allocate appropriate resources, and develop a plan for collaboration with relevant projects, partners, and initiatives. Moreover, proposals are expected to ensure that their dissemination and exploitation strategies feature dedicated (and possibly joint) actions for promoting their results and lessons learned on relevant platforms, such as the Cities Mission Platform, the Mission on Adaptation Platform[4] and CCRI website, and through related channels. Such activities will facilitate knowledge exchange, encourage the replication and uptake of solutions, and maximise impact. Synergies should be explored and, as appropriate, pursued with other relevant initiatives, such as the Green City Accord, European Urban Initiative, Hubs4Circularity, the Covenant of Mayors Europe and the New European Bauhaus.

Proposals should ensure due consideration of the requirements of the Urban Wastewater Treatment Directive, of work performed or underway in other relevant Horizon Europe funded projects, including under the Water4All co-funded partnership, and take account of the European Water Resilience Strategy.

This action supports the follow-up to the July 2023 Communication on EU Missions assessment[5].

Technology Readiness Level - Technology readiness level expected from completed projects

Activities are expected to achieve TRL 7-8 by the end of the project – see General Annex B.

[1] Directive (EU) 2024/3019 of the European Parliament and of the Council of 27 November 2024 concerning urban wastewater treatment (recast)

[2] The EU Mission on Climate-Neutral and Smart Cities aims to deliver 100 climate-neutral and smart cities by 2030 and ensure that these cities act as experimentation and innovation hubs to enable all European cities to follow suit by 2050. On 28 April 2022, the Commission announced the 100 EU cities that will participate in the Mission. In addition, 12 cities have been selected from countries associated or expected to be associated the Horizon Europe programme.

[3] See the list of Charter Signatories https://climate-adapt.eea.europa.eu/en/mission/the-mission/regions-and-local-authorities

[4] Initially established by MIP4Adapt and extended under the contract CINEA/2025/OP/0014

[5] COM(2023) 457 final and SWD(2023) 260 final