The concept of "Level 4" sewage treatment was first introduced in the European Municipal Sewage Treatment Guidelines



The European Parliament has published a revised draft of the new Municipal sewage Treatment Guidelines (UWWTD 91/271) : adding nutrient recovery targets and tightening the requirements for phosphorus discharge from sewage treatment plants. The draft is now before the European Parliament and the Council for discussion.

The guidelines are clear and simple and have been successful in improving water quality. Among them, the revised guidance identifies new pollutants, storm overflows and dispersed rural emissions to ensure that proposed solutions are consistent with green policy climate, biomethane production and circular economy objectives. Better recovery of nitrogen, phosphorus and other organic matter is tentatively planned for the period up to 2040.

The European Parliament estimates that this new regulation will lead to an increase in water prices of about 2.3%.

The proposed changes to the existing guidance include:

· Stricter emission limits for phosphorus and nitrogen (Appendix I) :

- 0.5 mg TP/L or 90% phosphorus removal rate (previously 1~2 mg/L or 80% removal rate);

- 6 mg N/L or 85% nitrogen removal rate (previously 10 to 15 mg/L or 70% to 80% removal rate);

- These limits are the same as the previous regulations and apply to wastewater treatment plants in eutrophication areas of > 10,000 population equivalent. However, additional provisions are also applicable to sewage treatment plants in non-eutrophically-sensitive areas > 100,000 population equivalent;

- The concept of non-eutrophication sensitive area is discarded (it was basically not processed before).

· The European Parliament will authorize the adoption of a bill to undertake a delegated act on minimum phosphorus and nitrogen utilization and recycling rates in sludge (Article 20)

ESPP notes:

- Nutrients may include organic carbon, but are in fact limited to N and P in the Act;

- The wording "utilization rate and recycling rate" should include the agricultural value-added part of agricultural sludge;

- Wording "minimum... "Rate" refers to the N and P in the sludge, not the nutrients that flow into the sewage treatment plant, which is not the same thing for N. Wastewater treatment plant P and N recycling are completely different. This does not take into account nutrients recovered at source, such as urine separation.

Wastewater treatment plants must be "energy neutral" by 2040. Energy neutralization is defined as "the total amount of renewable energy produced by a wastewater treatment plant" in quantity consistent with the total amount of energy consumed. Renewable energy here refers to the total amount of energy in the country, not each sewage treatment plant

ESPP note: This is very different from climate neutrality in that it does not take into account NOx, N2O and CH4 emissions from wastewater treatment plants, carbon emissions from sludge pipe disposal outside wastewater treatment plants, the climate impact of nutrient recovery (alternative fertilizers), and carbon sequestration of sludge back to field. The idea now is to sequester sewage and sludge on land. Indeed, such a phrase could simply mean that the installation of a number of wind turbines in a sewage treatment plant would seem to be sufficient.

· Collection and treatment of sewage from all concentrations > 1,000 population equivalent (originally 2,000 population equivalent) (Articles 3.2, and 6.2)

Introduction of a new concept of "Quaternary treatment" (Article 8 and Appendix I)

This requires the removal of at least 80% of indicative organic pollutants. Such treatment is required for all sewage treatment plants > 100,000 population equivalent and for all sewage treatment plants > 10,000 population equivalent that are identified as being at risk of pollution or discharging into swimming contact waters.

Extended Producer Responsibility (EPR) applies only to pharmaceuticals and cosmetics. In this way, the companies producing these products must bear the full cost of monitoring and level 4 treatment (Article 9 and Appendix III).

ESPP Note: Extended producer responsibility does not cover industrial chemicals such as PFAS and plastic additives, nor does it cover agricultural chemicals.

The European Commission will develop a method for measuring microplastics in sewage and sludge, which must then be monitored in sewage treatment plants of > 10,000 population equivalent (Article 21).

· Promote reuse of reclaimed water (Article 15)

· The new concept of "Integrated Municipal Wastewater Management Plan" is mandatory for all municipalities with a population equivalent of > 100,000 and for municipalities with a population equivalent of > 10,000 where stormwater or municipal runoff meets certain conditions (Article 5 and Appendix V)

· Redefine "sludge", "micropollutants" and "microbial resistance" (Article 2)

Note: The above obligation is the final requirement of the proposal. In some cases, the intermediate level is fixed for certain date ranges. References to articles/attachments refer to published revised proposals (not those in the existing 1991 guidelines). The above is a simplified interpretation in many cases, please refer to the published regulatory proposals for details.

The European Parliament has also published proposed changes to environmental quality standards, groundwater and water framework guidelines. These relate to chemical contaminants in water and specifically to "new contaminants of concern," including PFAS, microplastics and pharmaceuticals.

The ESPP welcomes these ambitious and pragmatic proposals to continue to improve water quality in Europe, further limit the waste of phosphorus and nitrogen into the nutrient circular economy and address new pollutants, particularly PFAS, pharmaceuticals and microplastics.