Urban Wastewater Treatment Directive

The Council Directive 91/271/EEC concerning urban waste-water treatment was adopted on 21 May 1991. Its objective is to protect the environment from the adverse effects of urban waste water discharges and discharges from certain industrial sectors and concerns the collection, treatment and discharge of domestic waste water, mixture of waste water and waste water from industrial sectors.

Principles

Four main principles are laid down in the Directive:

Planning

The planning aspects of the Directive require Member States to:

   Designate sensitive areas (sensitive water bodies) 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

The regulation aspects of the Directive require Member States to:

   Establish systems of prior regulation or authorisation for all discharges of urban wastewater;
   Establish systems of prior regulation or authorisation for discharges of industrial wastewater into urban sewage collecting systems to ensure:
       Treatment plant operation and sludge treatment will not be impeded;
       No adverse effect on the environment (including receiving waters) 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, such as heavy rain;
   Ensure that wastewater treatment is provided for all agglomerations at the level specified by the Directive and within the required deadline:
       Secondary treatment is the basic level that should be provided, with more stringent treatment being required in sensitive areas and their catchments;
       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;
       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 (86/278/EEC), incineration (89/429/EEC and 89/369/EEC), and landfill (99/31/EC) are respected. The disposal of sewage sludge to surface waters is banned.

Monitoring

he monitoring aspects of the Directive require Member States to ensure that monitoring programmes are in place and that the programmes correspond to the requirements laid down in Annex I D of the Directive (en pdf 160KB) in terms of parameters monitored, analytical method and sampling frequency. Member States are required to ensure that both discharges from urban wastewater treatment plants and receiving waters are monitored.