Urban Waste Water Treatment Directive (91/271/EEC)

Directive No 91/271/EEC concerning urban waste water treatment (OJ L 135/40) as amended by Directive 2013/64/EU (OJ L 353, 28.12.2013, p. 8-12) concerns the collection, treatment and discharge of urban waste water and the treatment and discharge of waste water from certain industrial sectors and is intended to prevent environmental damage caused by the discharge of inadequately treated urban waste water.

Requirements of the Urban Waste Water Treatment Directive

The main measures regulated by this Directive are

• adherence to a schedule for the construction and expansion of sewerage systems and municipal wastewater treatment plants,
• the regulation of requirements for biodegradable industrial wastewater from certain industries with more than 4,000 PE₆₀ that is discharged directly into bodies of water
• the regulation of the disposal of sewage sludge and
• the monitoring of the treated municipal wastewater discharged.
• The update of a programme for the implementation of this Directive, which was planned as well, is not necessary, as the last deadlines for the implementation of the Directive expired on 31 December 2005.

The categorisation into so-called "sensitive" and "normal" areas is carried out in accordance with the Urban Waste Water Treatment Directive under the criterion that affected surface waters in sensitive areas are already eutrophic due to the discharge of (treated) municipal wastewater or would become eutrophic in the near future without further protective measures. The purpose of this categorisation is to establish appropriate purification levels for the protection of water bodies and the environment.

The monitoring of the national implementation measures is checked by the monitoring programmes. Likewise, all municipal wastewater treatment plants must carry out periodic analyses of the respective inflow and outflow values. In addition to the measurement frequency, the parameters to be analysed must also be precisely specified for these tests.

The Annex to the Urban Waste Water Directive specifies requirements for the concentration and/or the minimum percentage reduction of certain parameters, as well as rules regarding sampling, which must be complied with when discharging from municipal wastewater treatment plants.