Is the excavation of Japanese Knotweed material and screening (sieving) the material through a mesh or other selective system to remove rhizome fragments, which are then disposed of correctly and safely. The soil that passed through the screener will still be classed as controlled waste and may be used on site but must be located where it will not be disturbed. This soil will then need to be monitored for at least two growing seasons and any regrowth treated with herbicide, or dug out (usually manually), before control can be considered complete.
- Can be cost effective but not always.
- Less material needs to be disposed of to waste facility.
- The treated soil can be re-introduced on site as fill or in soft landscaping areas.
- Where soil needs to be imported, less is required from elsewhere to fill voids created by excavation.
- All screened soil is still classed as controlled waste
- Small fragments of Japanese Knotweed will still be present in the soil and could lead to re-infestation.
- Area where screened soils are re-used must be monitored for regrowth.
- Follow up herbicide treatment or manual removal may be required.
- Plant material can be accidently spread during movement.
- Soil type and makeup dictate if it can be screened or not.