Rotomolding Scrap Shredder — Reject Water Tanks & Large LLDPE Parts

No — and any supplier who says otherwise is selling you a machine the size of a room. A 1,000-litre tank is over a metre across in every direction; practical shredders have feed openings a fraction of that. The workflow that actually works is pre-cutting: a saw or cutter reduces the tank to panels in minutes, and panels feed steadily through a dual shaft machine’s top opening or the S3-600’s 600 × 1000 mm side hopper. Cutting is cheap, fast and turns an impossible object into routine shredder feed.

Both work; the choice is volume and wall thickness. A dual shaft machine grips flexible LLDPE panels between counter-rotating blade shafts and rips them through — effective on the rubbery, tough wall sections typical of tanks, with manual feeding. The S3-600 single shaft brings more power (22 kW) and a side-feed hopper that takes trolley-loaded panels, shredding 300–500 kg/hr and running 24 hours continuously. Occasional rejects point to the dual shaft; a steady reject stream or thick-wall industrial parts point to the S3-600.

Yes, with one extra step: rotomolding machines feed on pulverised powder, not regrind. The path is shred → grind → pulverise, after which the recovered LLDPE is typically dosed into non-critical products, inner layers of multi-layer tanks, or dark colours where the recycled fraction does not affect appearance. Reground material that skips pulverising still sells well to injection and extrusion processors, since rotomolding-grade LLDPE is premium polymer. Either route recovers far more value than selling uncut tanks to a dealer.

The reject rate itself is usually modest, but each reject is enormous — a single failed 2,000-litre tank can outweigh a week of trimming waste from smaller processes. Add kiss-off and vent trimmings, cutout sections from fitting manholes and outlets, and mold tryout parts, and a mid-size tank plant accumulates tonnes of LLDPE per year. Because the parts are hollow, the pile looks even bigger than it weighs — which is exactly why shredding for density is the first economic step.

Yes. Tanks with foamed middle layers or multi-layer walls shred mechanically just like single-layer parts, but the output is a mixed material — LLDPE with foam fraction — that cannot return to a premium single-polymer stream. Plants typically segregate multi-layer scrap and sell it as mixed regrind, or route it into applications where the foam content is acceptable. Keep single-layer and multi-layer rejects separate from the start; the price difference on the regrind justifies the two-bin discipline.

Every machine is quoted to the job. What moves the number is capacity, throat size, motor rating, MS or SS construction and the automation you add — a blower, a conveyor, a control panel. Our guide to what drives machine cost walks through each of those; send us your material and daily volume and we will size the machine and quote it, usually the same day.

Yes — cut a reject tank into sections, bring them to our works at Andheri East, Mumbai, and we will shred them so you can check throughput and shred quality on your actual wall thickness and material. We can also demonstrate second-stage grinding of the shred. Outstation plants can send sections by transport or request a video trial. Contact us to arrange it — Mon–Sat, 9 AM to 7 PM.