Urban Wastewater Treatment Directive (UWWTD 2): Anticipating a new framework for obligations and pollutant treatment in Europe

On 27 November 2024, the European Union reached a landmark milestone with the adoption of Directive (EU) 2024/3019 on urban wastewater treatment. This text, which lays down minimum requirements for the collection, treatment and monitoring of urban wastewater, is the result of a comprehensive recast of the 1991 directive. However, it goes far beyond a mere technical update. It marks a structural shift designed to align wastewater management with the One Health approach, while also reducing greenhouse gas emissions, improving the sector’s energy balance and supporting the transition towards a circular economy.

1. A systemic expansion of the scope of application

The assessment of the previous regulatory framework showed that significant sources of pollution remained insufficiently addressed. According to the European Environment Agency’s 2018 report on European waters, small agglomerations exert significant pressure on 11% of the EU’s surface water bodies. To better tackle pollution at source and prevent untreated urban wastewater from being discharged into the environment, the new directive expands its obligations both territorially and technically. 

Inclusion of small agglomerations

The compliance threshold for collection systems and secondary treatment of organic pollution has been lowered from 2,000 to 1,000 population equivalents (p.e.). Member States must ensure that agglomerations between 1,000 and 2,000 p.e. are equipped with collection systems by 31 December 2035, and that discharges from urban wastewater treatment plants serving these agglomerations comply with secondary treatment requirements by the same deadline. This measure aims to eliminate direct untreated discharges, particularly in rural and peri-urban areas. 

Integrated stormwater management

One of the key pillars of the recast concerns urban runoff and storm water overflows. The directive requires integrated urban wastewater management plans to be established for all agglomerations of 100,000 p.e. and above by 31 December 2033, as well as for risk-prone agglomerations between 10,000 and 100,000 p.e. by 31 December 2039. These plans must prioritise green and blue infrastructure solutions wherever possible. 

The directive sets an indicative, non-binding objective that storm water overflows should represent no more than 2% of the annual collected urban wastewater load, calculated under dry-weather conditions. Importantly, before considering storage or treatment measures, integrated management plans must first assess preventive solutions aimed at avoiding the entry of unpolluted rainwater into collection systems, including natural water retention, rainwater harvesting and the expansion of green and blue urban spaces.  

Regulation of individual systems

Where connection to a collection system is not technically feasible, would involve excessive cost, or would not provide environmental or public health benefits, individual systems such as septic tanks may be authorised by way of derogation. However, the directive now requires these systems to be designed, operated and maintained in a way that achieves the same level of environmental and human health protection as secondary and tertiary treatment. Member States must also register such systems and ensure regular inspections or controls based on a risk-based approach.

2. Technological upgrading: tertiary and quaternary treatment

The directive introduces a stricter treatment hierarchy to address both eutrophication and chemical contamination. 

Treatment level	Main targets	Implementation thresholds	Final deadlines
Secondary	Organic matter: BOD5, COD	Agglomerations of 1,000 p.e.	2035
Tertiary	Nitrogen and phosphorus	More than 150,000 p.e. (all discharges) / agglomerations of 10,000 p.e. and above discharging into eutrophication-sensitive areas	2039 / 2045
Quaternary	Organic micropollutants	More than 150,000 p.e. (all discharges) / agglomerations of 10,000 p.e. and above discharging into micropollutant-risk areas	2045

The technological leap of quaternary treatment

Quaternary treatment is one of the flagship innovations of the recast directive. It is intended to reduce substances that may pollute water even at very low concentrations, including pharmaceutical residues and substances associated with cosmetic products. The treatment plants concerned will have to demonstrate an average removal rate of at least 80%, calculated on the basis of selected indicator substances.

These indicators include complex molecules such as carbamazepine, diclofenac and venlafaxine.

3. Extended Producer Responsibility

Article 9 introduces the polluter-pays principle into the financing of wastewater treatment. The pharmaceutical and cosmetics industries are directly targeted because their residues are the primary source of the micropollutants detected in wastewater.

Scope of financing

By 31 December 2028, producers placing the relevant products on the EU market will be subject to extended producer responsibility. They will be required to cover at least 80% of the full costs of complying with quaternary treatment requirements, including both investment and operating costs, as well as the costs of monitoring micropollutants.

Their financial contribution will be determined on the basis of the quantities and hazardousness, in urban wastewater, of the substances contained in the products they place on the market.

Exemption criteria: the burden of proof

A producer may be exempted where it can demonstrate that:

1. the quantity of substances contained in the products it places on the EU market is below one tonne per year; or 

2. the substances contained in those products are “rapidly biodegradable” in wastewater or do not generate micropollutants in wastewater at the end of their life. 

The European Commission must adopt detailed criteria for the uniform application of the biodegradability and hazardousness exemption by 31 December 2027. For industry, anticipating these criteria will therefore be a major strategic issue, both from a compliance perspective and in terms of product formulation and portfolio management. 

4. Energy neutrality and circular economy

The directive requires the urban wastewater sector to become an active contributor to the energy transition.

Towards renewable-energy coverage

The objective is to achieve energy neutrality for the urban wastewater treatment sector by 2045. This target applies, at national level, to urban wastewater treatment plants treating a load of 10,000 population equivalents (p.e.) and above, including their connected collecting systems. Mandatory energy audits will be required every four years for the relevant installations.

The energy required to cover the sector’s needs must progressively come from renewable sources generated by or on behalf of wastewater treatment plant owners or operators, whether on-site or off-site, including biogas, solar and wind energy. Energy audits must cover both treatment plants and their associated collecting systems: by 31 December 2032 for installations above 100,000 p.e., and by 31 December 2033 for those between 10,000 and 100,000 p.e.

Resource recovery

The legislation also promotes the reuse of treated wastewater, particularly in water-stressed areas, provided that human health and environmental safety are ensured, notably in the case of agricultural irrigation. 

In parallel, phosphorus recovery from sewage sludge becomes a strategic priority. By encouraging nutrient recovery, the directive supports the circular economy and contributes to reducing the Union’s dependence on imported fertilisers.

5. Governance, transparency and health srveillance

   
   

The directive strengthens citizens’ rights and expands monitoring obligations.

• Health surveillance. The text institutionalises wastewater-based epidemiological surveillance, covering public health parameters such as SARS-CoV-2 and its variants, influenza viruses, poliovirus and emerging pathogens, as well as antimicrobial resistance (AMR). 

However, monitoring is not limited to epidemiological surveillance. It must also help detect the presence of microplastics, PFAS and metals in urban wastewater and sludge, thereby reinforcing a precautionary approach to emerging pollutants. 

• Cost transparency. Agglomerations of more than 10,000 p.e. will have to provide households with clear information on the costs of measures implemented to protect public health and improve treatment performance.

• Access to sanitation. Member States must identify vulnerable and marginalised groups and improve their access to sanitation facilities, including in public spaces. 

  
  

6. Critical implementation milestones

Date	Regulatory milestone
1 January 2025	Official entry into force of the directive.
31 July 2027	Deadline for Member States to transpose the directive into national law.
31 December 2027	Publication by the Commission of EPR exemption criteria, including biodegradability criteria.
31 December 2028	Effective implementation of Extended Producer Responsibility schemes.
31 December 2030	First energy-neutrality milestone: renewable energy generation equivalent to 20% of annual energy use.

Conclusion : 

Directive (EU) 2024/3019 is not merely a regulatory update; it represents a profound structural transformation that redefines urban wastewater management as a central pillar of public health protection and climate resilience within the European Union. 

By embedding the One Health approach and introducing fourth-generation treatment standards, the European legislator is placing Member States and economic operators on an unprecedented path towards higher environmental and operational performance.

In this respect, the introduction of Extended Producer Responsibility (EPR) represents a major financial and operational challenge for the pharmaceutical and cosmetics industries. 

The 31 December 2028 deadline for the implementation of this regime requires companies to immediately reassess their market access strategies and to rigorously document the biodegradability of the substances they place on the market.

At the same time, the objective of achieving energy neutrality by 2045 transforms wastewater treatment infrastructure into genuine renewable energy production and resource recovery units, including for critical resources such as phosphorus, thereby strengthening the European Union’s strategic autonomy.

In this increasingly complex regulatory environment, anticipation will be key to compliance. The transposition period, ending on 31 July 2027, should be used by local authorities and industry stakeholders to assess their risks, structure their technical documentation and prepare for the forthcoming EPR exemption criteria expected by the end of 2027.

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Authors: Floriane Demailly & Loris Mistrulli