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Environment

Sewage sludge

EU rules promote the use of sewage sludge in agriculture, but regulate its use to prevent harmful effects on soil, vegetation, animals and people.

Sewage sludge
© MarioGuti / Getty Images

Overview

Sewage sludge is a mud-like residue resulting from wastewater treatment. Sewage sludge contains heavy metals and pathogens such as viruses and bacteria. It also contains valuable organic matter and nutrients such as nitrogen and phosphorus, and can therefore be very useful as a fertilizer or soil improver.

Background

The quantity of sewage sludge requiring disposal in the EU is increasing, mainly due to the progressive implementation of the Directive on the treatment of urban wastewater.

EU rules on sewage sludge consider the nutrient needs of plants and ensure that the quality of soil, the surface and ground water is not impaired. It covers

  • how farmers can use sewage sludge as a fertiliser
  • the sampling and analysis of sludge and soils
  • keeping detailed records for sludge quantities produced and used in agriculture
  • the type of treatment and sites where sludge is used
  • sludge composition and properties

Normally, sludge must be treated to reduce its fermentability and the health risks resulting from its use. In some EU countries, untreated sludge can be used in farming if it is injected or worked into the soil. In certain cases, sludge cannot be used at all. This includes

  • on soil in which fruit and vegetable crops are grown, except for fruit trees
  • on grassland or forage land that will be grazed by animals or harvested in the next three weeks

less than ten months before fruit and vegetable crops are to be harvested, when the crops are in direct contact with the soil and eaten raw

Objectives

The aims of the Sewage Sludge Directive are 

  • to protect humans, animals, plants and the environment by ensuring that heavy metals in soil and sludge do not exceed set limits
  • to increase the amount of sewage sludge used in agriculture

The Directive also

  • sets limits for the concentration of seven heavy metals in sewage sludge intended for agricultural use and in sludge-treated soils (cadmium, copper, nickel, lead, zinc, mercury, chromium)
  • bans the use of sewage sludge that results in concentrations of these heavy metals in soil exceeding these limit values

Implementation

EU countries must send reports on the implementation of the Sewage Sludge Directive to the European Commission every three years. These must be based on a specific questionnaire.

In 2018, a review on the implementation of EU waste legislation (including sewage sludge) was published.

Evaluation

A 2014 evaluation found that

  • the Directive has achieved its initial objectives, by increasing the amount of sludge used in agriculture and by reducing environmental harm
  • there were several areas where the Directive did not fully match the needs and realities of the current situation

Since then, there have been  scientific progress and technological developments, as well as changes in the policy landscape resulting from the first and second Circular economy action plans, the Bioeconomy Strategy, the new Fertilising Products Regulation, the Farm to Fork Strategy and the EU Biodiversity Strategy for 2030.

Therefore, a study was launched in 2020 to assess the evaluation criteria of the effectiveness, efficiency, relevance, coherence and EU added value of the Sewage Sludge Directive in all EU countries. This will build on and complement previous evaluation results. The results of the evaluation will inform the Commission’s decision on the need to progress with an impact assessment for a proposal to revise the Directive, as outlined in the New Circular Economy Action Plan.

Consultation activities aim to

  • complement already known data and literature review on the implementation of the Sewage Sludge Directive, among other things
  • understand the extent to which the Directive has been successfully implemented, the extent to which its objectives have been met, the main challenges, and any trade-offs in the implementation

Find out more in the Consultation Strategy for this evaluation and contribute to the open public consultation.

Timeline

Key dates related to the Sewage Sludge Directive

  1. December 2020 - Q1 2021
    Targeted stakeholder consultation activities to inform the evaluation of the evaluation of the Sewage Sludge Directive
  2. 20 November 2020- 5 March 2021
    Open public consultation on the evaluation of the Sewage Sludge Directive
  3. 18 June 1986
    Sewage Sludge Directive enters into force

Contact

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