New UK Environment Agency Statement on Leachate Irrigation

There has been a gap in the information provided by the UK environment Agency since last year when the BAT Guidance for leachate treatment was publised on the web site www.environment-agency.gov.uk .

The whole area of leachate treatment by irrigation, which is still practised in the UK at a few landfill sites, and which is used to a much greater extent in Europe generally, was until now without any guidance.

To a certain extent that gap has been closed by the position statement published in February, which can be read here.

The regulatory position statement covers the application of treated landfill leachate to short rotation coppice (SRC), but the principles described would presumably also apply to other forms of irrigation (eg grass plot).

In other EU countries, including Scandinavia (which is normally seen as exemplary in their application of environmental controls), the rules are much more relaxed as follows:-

- They allow untreated leachate to be irrigated to short rotation coppice (SRC)

- They allow irrigation not only during soil-moisture deficit periods, but also in many cases when there is not a soil-moisture deficit, so in Europe such schemes entail run-off during irrigation from the irrigated area during wet weather.

- They do not require the base of the irrigated area of treated landfill leachate to short rotation coppice (SRC) to be engineered and to have a barrier to prevent any loss to groundwater, as this is prohibitively expensive for such an otherwise inherently low cost process.

The question has to be asked that if the UK Environment Agency (EA) consider that the EU regulations such as the EU Groundwater Directive, and the EU Landfill and Waste Management Directives require them to take this position, why are not the other EU states applying equal stringency?

Finally, the position statement makes no reference to the dilute leachate which emerges from many old landfill sites in large volumes, where often a lack of original engineering design allows the leachate to become extensively diluted by groundwater.

These old leachates are often very dilute in nature, yet still environmentally damaging, and the techniques which would be applicable under BAT to these would hardly be those which would be applicable for a strong leachate from a WM Licensed or Permitted site. Yet there is still no UK EA guidance on BAT for these examples of leachate.

In my view the effect of this interpretation of the EU regulations will be that the potential opportunity for the nutrients from leachate, which could otherwise be used to water and fertilise extensive use of willow coppicing, much of which in turn could be used for biomass energy production, will be lost.

If it can be done elsewhere, as it is being done, with proper scientific monitoring and control, it should be possible to do this within the UK.

We would be pleased to receive your views - comment on the leachate blog or email me steve.last[at]virgin.net with your views, which if suitable and with your permission, we would like to publish. See also www.leachate-irrigation.com .