Nimrod Environmental limited

Overview

Nimrod are specialists in Japanese Knotweed eradication and through our vast knowledge of the problem, legislation, client needs and plant morphology we have all the solutions.

We aim to provide our clients with a sustainable solution for every site situation using a combination of traditional eradication techniques and utilising advances in the market such as Direct Chemical Injection, Rhizome Extraction and Root barrier systems. Through science and innovation we aim to provide the most cost effective and efficient treatment methods.

Using Direct Chemical Injection chemical treatment is more efficient as through introduction of herbicide directly into the stem of the plant this allows for lower dosage levels to be used safeguarding the surrounding environment, lowering costs to the client and cutting eradication times.

Our root barrier systems use the latest technology in geo-textile membranes, welders and adhesives to provide effective protection to your site. We utilise our root barrier systems in a number of situations such as encapsulation in on-site borrow pits, boundary root barriers and they are also successful in the footprints of buildings which have already been built on Japanese Knotweed contaminated land.

If space is at a premium on a site rendering burial and waste management options useless we are able to screen the contaminated material using trained technicians to separate out the Japanese Knotweed rhizome. This has the advantage of reducing the amount of contaminated material that needs to be removed from site (Often less than 1% of the total material excavated) leaving behind clean material which can be incorporated into the landscaping.

Treatment Methods

Chemical Tretment

Chemical treatment is by far the cheapest option for eradication of Japanese Knotweed. Chemicals can be applied by both spraying and direct chemical injection into the plants. There are a number of chemicals on the market which can be used for eradication of Japanese Knotweed and other invasive weeds which fall into two distinct categories.

Non-Residual herbicides

These herbicides are translocational which means that when applied directly onto live plant tissue they pass through the system into the roots and kill the plant from within. They are the only chemicals which can be used within 5 metres of a watercourse provided that Environment Agency approval is granted through a AqHerb01 notification form. Complete eradication of Japanese Knotweed using these methods can take between 3 and 5 years of repeated treatment.

Residual Herbicides

These herbicides bind to soil particles and from a barrier within the ground which can persist for up to 2 years. Surface growth of Japanese Knotweed can be eradicated within 12 months of the growing season however underground rhizomes can still be viable for a number of years, therefore if this barrier is compromised through excavation or other disturbances then re-growth can still occur.

Excavation

On development sites there are often time constraints for treatment of Japanese knotweed, excavation and relocation of the contaminated material on or off-site can often provide the solution. Due to Environment Agency guidelines of root growth which is 7 metres either side of visible stands and 3 metres down the volume of potentially contaminated material which needs to be treated can be very large. Nimrod Environmental have experienced staff who can follow the root structure ensuring that it is all removed without excavating unnecessary material. There are a number of methods which can be employed depending on your site requirements.

Excavation and Relocation to Waste Management Area

If the Japanese Knotweed contaminated material is within the build zone of proposed buildings it can be relocated to an area of the site which is not going to be developed in the near future or an area of Public Open Space (POS). Here chemical treatment can be carried out and in many cases after treatment is complete the material can be incorporated into soft landscaping.

Excavation and Burial on-site

If space is more limited a borrow-pit can often be the best solution. The contaminated material is buried under a minimum 2 metres of clean fill encapsulated within a sealed geo-textile membrane.

Excavation and Removal to Licensed Landfill.

If there is very little space for on-site treatment then the only remaining option may be to take the material off-site to a Licensed Landfill. This option is the most expensive however is a very fast solution to the problem.

Rhizome Extraction

Another option when space is at a premium on a site is to screen the contaminated material using trained technicians to separate out the Japanese Knotweed rhizome.

This has the advantage of reducing the amount of contaminated material that needs to be removed from site (Often less than 1% of the total material excavated) leaving behind clean material which can be incorporated into the landscaping.

This method cannot be relied upon to remove 100% of Japanese Knotweed material however by strategically placing the screened material where it can be easily accessed it can be monitored and any re-growth treated under our management plan and Insurance Backed Warranty.

Root Barrier Systems

Our root barrier systems use the latest technology in geo-textile membranes, welders and adhesives to provide effective protection to your site. We utilise our root barrier systems in a number of situations such as encapsulation in on-site borrow pits, boundary root barriers and they are also successful in the footprints of buildings which have already been built on Japanese Knotweed contaminated land.