*Five years after the deadline for implementation, the UK is still working to comply with the Urban Waste Water Treatment Directive, but much progress has been made, says Rob Moore.*

While the European Water Framework Directive (WFD) has been taking all the headlines in recent months, work to implement older water quality directives such as the Urban Waste Water Treatment Directive (UWWTD) has been proceeding with a lower profile. The European Commission regards the UWWTD and the Nitrates Directive as key pieces of legislation to control point and diffuse sources of water pollution, as required by the WFD. The full implementation of the UWWTD is a pre­requisite for meeting the key objective set out in the WFD: to achieve "good status" in all water bodies in the European Union by 2015.

The two deadlines of 31 December 2000 and 31 December 2005 for meeting the main requirements of the UWWTD have now passed for EU-15 countries (those states that joined the European Union before 2004), while transitional periods and later deadlines have been agreed for EU-12 countries (states that acceded to the EU in 2004 and 2007).

The UK water industry is continuing to carry out UWWTD-driven improvements, including installing nutrient removal at wastewater treatment works discharging to sensitive waters and reducing the frequency that intermittent discharges from storm overflows occur. A further 180 UWWTD-driven "actions" have been identified in the National Environment Programme for the fifth asset management plan period (2010-15) in England and Wales.

*Sensitive areas*

Continuing implementation of the directive also includes a four-yearly review of "sensitive areas". Water bodies may be defined as sensitive based on three factors:

* if they are eutrophic, or may become eutrophic in the near future if protective action is not taken;

* if they exceed or could exceed a specified concentration of nitrate;

* if wastewater treatment works discharges are subject to more than secondary treatment to comply with the standards of other directives - for example, advanced treatment required to meet the microbiological standards of the Bathing Waters Directive.

As of 2009, there were 525 designated sensitive areas in the UK. These cover an area of more than 2,650km2. The government will announce the designation of any new sensitive areas this year. Operators of wastewater treatment works will then be required to install more advanced treatment, such as nutrient removal.

*More energy and chemicals*

The water industry has expressed concerns relating to increased energy use (and associated carbon emissions) and chemical use to achieve the nutrient removal required. For example, phosphate removal by the use of ferric salts is an effective approach to achieve compliance with discharge consents for phosphate. However, in addition to adverse impacts on energy usage and the consumption of raw materials, the release of iron in the effluent has its own environmental impact on the chemistry and biology of the receiving water body.

As a consequence, the release of iron in the discharge also requires a consent based on river needs to reduce the risk of adverse impacts. Iron standards on consents may result in the need for iron removal that would further add to capital expenditure and operating expenditure and consumption of energy and materials.

The Commission monitors the implementation of the UWWTD across the EU. Its latest report on implementation was published in August 2009 and showed that the UK failed to provide suitable information to be included in the assessment. The Commission initiated legal action against the UK government for non-implementation of the directive in relation to the designation of sensitive areas.

*UK prosecution?*

In December 2009, the government won the case due to a lack of evidence that elevated nutrient and algae levels in the areas in question caused eutrophication and consistent disturbances to the balance of organisms. The Commission is now pursuing a new case against the UK on ineffective collecting systems in London and Whitburn in the North East, relating to intermittent discharges from storm overflows.

One of the most significant single investments driven by the UWWTD requirement to improve intermittent discharges is the construction of the Thames Tideway tunnels. The project, being implemented by Thames Water, is likely to comprise two tunnels below London. These will redirect storm overflows currently discharging to the River Lee and the River Thames to an improved wastewater works at Beckton. Overall, the tunnels will collect spills from 35 sewer overflows.

*Other EU states*

With regards to other member states, only 18 of the 27 provided sufficient information to be included in the latest review. This covered 53 per cent of the total wastewater load generated in the EU. The report, which uses data from 2005, shows that a number of states failed to comply fully by the required deadlines. Overall, secondary treatment was in place for 87 per cent of the EU-15 population, with 100 per cent compliance in Austria, Denmark, Germany and the Netherlands, and 64 per cent compliance in France. In Portugal, secondary treatment was in place for 41 per cent of the population and, most notably, some large cities in this country did not have any form of wastewater treatment. Romania had similar problems.

The Commission has previously acknowledged that the directive poses one of the most serious implementation problems in the EU. Nevertheless, the latest report shows that considerable progress has been made since the previous report, which refers to 2003 data. Water collecting systems are now in place for more than 95 per cent of the EU-15 population, and most EU-12 countries are advancing well towards compliance with the secondary treatment requirements, although some need to make greater effort.

The UWWTD has been a significant driver for investment in the UK. Since AMP2 began in 1995, following the implementation of the UWWTD in 1991, more than £10.5 billion has been spent by the water industry on improvements to wastewater treatment and intermittent storm overflow discharges.

Rob Moore is a policy adviser at WRc, which has been working with the Commission since 2002 to provide technical advice on the implementation of the UWWTD across the EU.