Road-legal towable pilot plants — hitch up to a 3.5 t-rated vehicle, drive to site, connect water/power/data, run the trial within an hour of arrival. The fastest deployment form factor and the right choice when the same pilot needs to move between several sites in a single campaign.
Speed of Deployment Is the Deciding Factor
A trailer-mounted pilot is ready-to-run when it arrives at the site. No crane, no foundation, no on-site assembly — chocks down, jacks deployed, connections made, commissioning starts. Setup is measured in hours, not days. This pays off when the trial is short, the trial schedule is tight, or the same pilot needs to move between three or four sites in a single campaign.
The trade-off is logistics: a trailer needs a road. If the site can’t take a 3.5 t vehicle and trailer, the choice is a skid-mounted build instead.
Why a Trailer
From hitch-on to first sample in under one working day. Compared to 3–5 days for a containerised build or 1–3 days for a skid build, this is the difference between catching a process window and missing it.
The same trailer can run a four-week trial at four different sites in a single quarter. Each site gets identical pilot equipment, identical operator, identical data acquisition — producing genuinely comparable results.
Built to fit a 3.5 t braked-trailer limit (UK Cat BE) or 750 kg unbraked. Anyone with the appropriate driving licence can tow it. No HGV operator required, no schedule dependency on heavy-haulage contractors.
One 16 A or 32 A 3-phase plug. Connect to the site’s nearest distribution board, the genny that the contractor brought, or a hire generator if neither is available.
The whole pilot is wet-commissioned in the workshop before despatch. By the time it reaches the site, every connection has been pressure-tested and every controller has run through its setpoints.
The trailer hardware is independent of any specific project — after a campaign it comes back to the workshop, the internals are re-configured for the next brief, and it goes back out.
Three Common Sizes
| Trailer | Bed L × W | Gross weight | Towing licence | Typical pilot duty |
|---|---|---|---|---|
| Light box trailer | 2.5 × 1.5 m | 750 kg unbraked | UK Cat B (any car driver) | Single-process pilot (e.g. dosing rig only) |
| Standard pilot trailer | 3.5 × 2.0 m | 2,500 kg braked | UK Cat BE | Coag-floc + DAF or compact biological train |
| Large pilot trailer | 5.0 × 2.4 m | 3,500 kg braked | UK Cat BE | Full multi-stage train (intake, treatment, polishing, sampling) |
Above 3,500 kg the unit moves into the HGV category, loses its road-legal car-towable advantage and becomes a static skid in practice. We don’t build "trailer-mounted" pilots above this limit — switch to containerised instead.
Honest View
3,500 kg is a hard ceiling. Every kg of frame, tank, pump, chemical and sample is counted.
Aluminium frame instead of steel where the duty allows. Light-grade FRP tanks. Pre-fab modules with optimised mass. Each design is mass-budgeted from the start with a 10 % margin for in-trial spares.
A 3.5 t trailer needs a road, turning circle and standing area. Many remote sites don’t have them.
Pre-deployment site survey: turning radii, ground bearing capacity, overhead clearance. If the survey fails, we recommend the skid-mounted variant instead and estimate that.
A road-accessible trailer is the easiest target for theft and vandalism.
Hitch lock, wheel clamps, anti-tilt sensor with SMS alert, internal CCTV. For high-risk sites we recommend the containerised envelope which is much harder to attack.
Open-top trailers fail in winter. Fully-enclosed box trailers add weight.
Insulated box body sized to keep the mass budget; weatherproofing rated for the campaign-window climate; integral roof rack for solar panels if the trial includes off-grid power.
Site distribution boards often don’t have a free 32 A 3-phase outlet at the right RCD curve.
Detachable power-conditioning module that handles a wide input range (single-phase, 3-phase, generator). Soft-start on the heaviest motors to avoid tripping the site RCD on startup.
Road vibration shakes loose fittings, breaks instrument connections, settles solids in tanks.
Vibration-rated mounting on every instrument; locking fittings throughout; pre-transit empty-and-strap protocol for liquid-holding equipment. Post-arrival inspection checklist with sign-off.
Where Trailer-Mounted Wins
Compare four water sources for a regional desalination programme — same pilot, four sites, four months. Genuinely comparable data.
2–4 week treatability trials where the cost of a containerised build cannot be amortised across the campaign.
Industrial spill or compliance breach — trailer on the road within 24 hours, running within 48.
Run the same wastewater through your trailer pilot at three potential treatment-equipment vendors’ sites to validate their performance claims independently.
Park the trailer at an operating plant, tap a slip-stream off the main works to trial a new chemistry or new process choice without disturbing the existing operation.
Towable kit that fits the academic logistics chain — arrives with the visiting researcher, runs the experiment, returns with them and the data.
All five form factors.
Hub PageWhen the road runs out.
Read MoreWhen the campaign is long.
Read MoreLightweight space-frame for visibility.
Read MoreConstraints every remote pilot solves.
Read MoreThe broader pilot-testing service hub.
Read MoreSource-water characterisation in trailer form factor.
Read MoreTrailer fabrication and pilot fit-out.
Read MoreTell us the sites, the campaign window and the treatability question — we will estimate a trailer build that visits all of them.
Our expertise spans multiple industries with sector-specific water treatment solutions.