Invasive Species & Vegetation Incinerators

Invasive species waste is the cut, dug or scraped material from a stand of a plant whose spread is controlled by law — Japanese knotweed and its hybrids, giant hogweed, Himalayan balsam, rhododendron ponticum, New Zealand pigmyweed — together with the ragwort and other injurious weeds a holding is expected to control. Under the Wildlife and Countryside Act it is an offence to plant or otherwise cause these species to grow in the wild, and once cut, the arisings are controlled waste under environmental protection law. The problem with this stream is regeneration, not volume. Japanese knotweed regrows from rhizome fragments of well under a gram; Himalayan balsam sets thousands of seeds per plant; pigmyweed re-establishes from a single node. Chipping spreads it. Composting keeps it viable. Stockpiling it in a corner of the yard for collection creates a new stand under the pile. Every intermediate step between cutting and destroying is a chance for the material to do the one thing it is good at. Moving it is the other cost. Knotweed-contaminated arisings and soil going off site need a licensed carrier and a facility permitted to take them, and the gate fees on contaminated soil in particular are what make a clearance expensive. Burning on the site of production removes the movement, the carrier, the gate fee and the risk of the material seeding along the route. Combustion at 850–1,200°C with two-second retention above 850°C destroys rhizome, crown, stem, seed and root fragment together. There is nothing viable in 3–5% mineral ash. Where a management plan or a development condition requires evidence, the cycle log dates the destruction against the clearance.

1,800 kg of cut arisings ÷ 450 kg per charge = 4 charges on the AGBI-450, one a day, and 54–90 kg of ash at 3–5% — with no licensed carrier movement of controlled material off the site. Green arisings are wet and bulky, so expect the chamber volume — 0.76 m³ on the AGBI-450 — to fill before the weight rating on freshly cut stem, and add fuel for driving off moisture.

Yes. Rhizome, crown, stem and root fragment are all destroyed by primary combustion at 850–1,200°C with two-second retention above 850°C in the secondary chamber. Nothing viable survives into the 3–5% mineral ash — which is the point, given that a fragment weighing under a gram is enough to establish a new stand.

In a permitted incinerator, yes — you need an environmental permit from the Environment Agency, SEPA or NIEA covering the activity and the waste codes. What you cannot do is burn it as an unpermitted fire, and you should not chip, compost or stockpile it, because those are the steps that spread it.

You can, and it needs a registered carrier and a facility permitted to accept it. The cost is haulage plus gate fees, and the risk is the journey — contaminated material has to be loaded, moved and tipped without shedding fragments. On-site destruction removes all four.

No, not in bulk. Soil does not combust: it soaks up the heat the charge needs, fills the chamber with inert mass and multiplies the ash you rake out. The incinerator handles the plant fraction; soil has its own routes, including on-site burial under the relevant permission or a permitted facility.

Freshly cut green material burns, but the first part of the cycle is spent driving off moisture, so it costs more fuel and more time than dry material. If the load can be stood and dried while contained, do it. If containing it while it dries is not practical, burn it green — same-day destruction beats a drying stockpile.

The sap is phototoxic and causes severe burns on exposure to sunlight, so handling needs full skin and eye protection from cutting through to charging. The hazard is in the handling; once the charge door is closed the material is no different from any other vegetation.

Only if the permit says so. Accepting third-party waste is a different activity from destroying your own arisings, and it has to be covered before the first load arrives rather than afterwards.

One charge a day is the realistic figure — a full 500 kg charge runs past a single eight-hour shift — so an AGBI-500 clears around 2.5 tonnes of arisings in a five-day week. On green vegetation, expect the chamber volume rather than the weight rating to set the charge size.