Urban Wastewater Treatment Directive

The Council Directive 91/271/EEC concerning urban waste-water treatment was adopted on 21 May 1991. The aim of this directive is to protect the aquatic environment from the adverse effects of discharges of untreated or improperly treated urban waste water and waste water from industrial sectors and concerns the collection, treatment and discharge of domestic water, mixture of waste water and wastewater from certain industrial sectors.

Requirements

• The Collection and treatment of waste water in all agglomerations of >2000 population equivalent (p.e.)
• Secondary treatment of all discharges from agglomerations of > 2000 p.e., and more advanced treatment for agglomerations >10 000 population equivalents in designated sensitive areas and their catchments
• A requirement for pre-authorisation of all discharges of urban waste water, of discharges from the food-processing industry and of industrial discharges into urban waste water collection systems
• Monitoring of the performance of treatment plants and receiving waters
• Controls of sewage sludge disposal and re-use, and treated waste water re-use whenever it is appropriate

Principles

Four main principles are laid down in the Directive:

Planning

• Designate sensitive areas in accordance with three specific criteria, and to review their designation every four years
• Identify the relevant hydraulic catchment areas of the sensitive areas and ensure that all discharges from agglomerations with more than 10 000 p.e. located within the catchment shall have more stringent than secondary treatment
• Establish less sensitive areas if relevant
• Establish a technical and financial programme for the implementation of the Directive for the construction of sewage collecting systems and wastewater treatment plants addressing treatment objectives within the deadlines set up by the Directive (and the Accession Treaties for new Member States)

Regulation

• Establish systems of prior regulation or authorisation for all discharges of urban wastewater or industrial wastewater into urban sewage
• Collecting systems to ensure:

1. Treatment plant operation and sludge treatment will not be impeded
2. No adverse effect on the environment will occur and The safe disposal of sewage sludge

• Establish systems of prior regulation and/or specific authorisation and permits for food processing industries
• Ensure that all urban wastewater generated in agglomerations with more than 2000 p.e. are supplied with collecting systems, and that the capacity of these is such that all urban waste water is collected, taking account of normal local climatic conditions and seasonal variations
• Ensure that national authorities take measures to limit pollution of receiving waters from storm water overflows via collecting systems under unusual situations (heavy rain)
• Ensure that wastewater treatment is provided for all agglomerations at the level specified by the Directive and within the required deadline:

1. Secondary treatment is the basic level that should be provided, with more stringent treatment being required in sensitive areas and their catchments
2. For certain discharges in coastal waters treatment may be less stringent (i.e. primary treatment) under certain conditions and subject to the agreement of the European Commission
3. For agglomerations with a population equivalent of less than 2000 but equipped with a collecting system, appropriate treatment must be provided

• Ensure that technical requirements for the design, construction, operation and maintenance of wastewater treatment plants treating urban wastewater are maintained and that they ensure adequate capacity of the plant and treatment of urban wastewater generated in agglomerations taking into account normal climatic conditions and seasonal variations
• Ensure that the environment is protected from adverse effects of the discharge of wastewater
• Ensure that the environmentally and technically sound reuse or disposal of sewage sludge is subject to general rules, registration or authorisation and that the requirement of specific inter-linked Directives for agricultural re-use, incineration, and landfill are respected. The disposal of sewage sludge to surface waters is banned

Monitoring

• Ensure that monitoring programmes are in place and that they respond to the requirements in terms of parameters monitored, analytical method and sampling frequency
• Member States are required to ensure that discharges from urban wastewater treatment plants and receiving waters are monitored

Information and reporting

• Adequate mechanisms to allow the co-operation and exchange of information with other Member States in cases where discharges of wastewater have a transboundary effect on water quality of shared waters
• Adequate reporting procedures and databases to allow the provision of information to the Commission on:

1. Transposition of the Directive into national legislation, implementation programmes and situation reports on the disposal and re-use of treated urban wastewater and sewage sludge
2. Status of collecting systems, efficiency of treatment plants (i.e. treatment level and monitoring results) and the quality of receiving waters
3. Status of discharges from the food-processing industry to surface waters

• Access for the public to relevant information and the publication of status reports every two years on the status of wastewater collection and treatment and disposal or re-use of sludge