Welcome.

This site has been set up by waste management experts for the exchange of information about leachate irrigation, and related leachate management, treatment, and disposal techniques.

Please do enter your own irrigation site information, and you will be contacted for verification.
 

Final Draft November 2006

Important:
Most Leachate Processes described on this web site are NOT listed in the processes which will become part of the UK
BAT process guidance.
If you have views on this we welcome your comments.

“We believe that there is a continuing role for these processes in the UK, and throughout Europe.”

Common Leachate Irrigation Benefits and Methods

Leachate from landfills contains substances potentially beneficial to crops. It has also been shown in work by WRc and Imperial College that a strong relationship exists between the quantity of nitrogen removed from the leachate and the biomass yield of the crop (Alker 1999). During dry weather, growth rates will be improved due to the effect of maintaining adequate soil moisture.

Short Rotation Coppicing (SRC)

Short Rotation Coppicing (SRC) comprises the growth of willow, or poplar, for regular cutting and harvesting.

Short Rotation Coppicing has been shown to benefit from the application of leachate on some soils. Increased interest is being shown recently by the UK Government in subsidising the development of biofuel production, and “green” non fossil-fuel and biofuel (renewable energy) projects such as SRC may be suitable, if funding was available and a market exists locally for the fuel. A £1,000/hectare (GBP) UK subsidy has been available for SRC planting (2005), but how long this will continue is in doubt.

Pasture Irrigation

Irrigation to grassland/pasture has been shown to provide significant quantifiable benefits when the nutrients provided by leachate are in limited supply. Such benefits are specific to the soils irrigated, season and ambient temperature. Many grasslands on poor soils (including landfill capping), are deficient in salt (sodium chloride) for cattle grazing, and the resulting crop may be classified as deficient under ADAS guidance. The recommended minimum total sodium content of the grass required by productive livestock is 1.5g Na kg-1 Dry Mass. Coastal locations may already exceed this level from sea spray, but inland this may be found to be a significant benefit, subject to site specific trials.

At some locations up to 50% improvements in crop dry weight yield have been recorded after applying leachate irrigation.

Grass will grow when temperatures are above 5^oC, and suitable plot rotation practices can allow beneficial application over an extended period over each season. It should be noted that the continuous application of leachate, which may emerge from the wastes at temperatures significantly in excess of 10^oC, may maintain the temperature slightly above ambient on occasions.

Amenity Woodland

Application to amenity woodland can provide a beneficial use from the amenity value of the woodland. Public access would have to be limited to prevent risk of public contact with leachate. It is likely that the main amenity use is in the summer, when the main benefit from irrigation is also taking place. Sessile woodland would be protected, and the current land use preserved, by the irrigation activities. Some UK guidance allows ecological improvement to be considered to be a benefit.

Woodland

Application of dilute leachate to commercial woodland may also provide some possible beneficial use from the amenity value of the woodland, but this is questionable. Agricultural benefit would need to be demonstrated, if there was no ecological benefit. Unlike SRC and the coppicing willow species, which have a high soil moisture demand, commercial woodland species will be more tolerant of dry conditions, and will not normally benefit to the same extent from the additional moisture or the dilute leachate nutrients.

Crops

The benefits to grassland will also apply to crops. Like grassland there will be specific benefits relating to the nutrient requirements of particular crops. For example, sugar beet is known to require a high salt input, and leachate is an ideal source. Once again, nevertheless, the extent of the benefit will vary for different soils and seasons.

Miscanthus

Miscanthus (Elephant Grass) has been identified as a highly productive grass suitable for biofuel production. Its suitability for use at specific sites is not known, and will depend upon local demand for the fuel, plus soils and climatic requirements, and be subject to ecological considerations (e.g. possible escape into the wild). Benefits are likely to be close to those described for SRC above.