Definition of Distance to Target (DDT)#

The term distance to target represents the remaining effort required for a Member State to achieve compliance with the Directive for each requirement (per Article) at the reporting level. This is a conceptual tool not included in the Directive itself.

It indicates how far a Member State is from meeting the goals for collecting and treating wastewater. The rules used to define this concept are as follows:

  • Distance to target – collection: the total load of wastewater that should be collected according to the Directive but is not yet collected.

  • Distance to target – treatment: the total load of collected wastewater that is not treated at all or not treated adequately. Additionally, if the load of wastewater that is not collected or addressed through individual systems (IAS) exceeds 2%, this load is also considered to 8 require treatment[1]. Inadequately treated wastewater refers to discharged water that does not meet the Directive’s quality requirements, e.g., BOD₅, COD, and, where applicable, total phosphorus and/or total nitrogen concentrations.

Targets#

  • Collection target: All wastewater covered by the Directive (Article 3) is collected. The distance to target for collection shows how much wastewater is still uncollected or lost during transport.

  • Treatment target: All wastewater covered by the Directive (Articles 4 and/or 5) is adequately treated (meeting required treatment level and performance). The distance to target for treatment shows how much of the collected and uncollected wastewater is still not adequately treated.

  • Generally, the overall treatment target is that all wastewater from agglomerations >10,000 p.e. discharging into sensitive areas is adequately treated with more stringent treatment than secondary treatment. The distance to target figure for more stringent treatment indicates the amount of collected and uncollected wastewater not yet treated to this level.

Key Considerations#

  • Distance to target values cannot be compared directly to legal compliance values.

  • They provide a more nuanced view of Directive implementation because they take into account the compliant fraction of treated wastewater in agglomerations that are not fully legally compliant.