Vehicle wash bay design & construction

Slab, falls, drainage and settling

Good civil works start with the pad. Depending on your site and vehicles, that may be a concrete slab, but it doesn't have to be. What matters is that it's graded, so wash water runs to the collection point instead of pooling. The fall varies from site to site, so we set it to suit your ground, vehicles and drainage. Bunding or a perimeter hump keeps water inside the bay, and a silt trap sits ahead of the oil-water separator to catch coarse material and suspended solids before they reach it. Requirements vary by authority and site, so check what applies to you early. We plan the pad, falls, drainage and settling together, so the bay works as one system.

Oil-water separators and wash water treatment

Wash water can't simply run off site. Heavy vehicles wash off hydrocarbons and suspended solids, and in some cases heavy metals, so the water usually needs separating and treating before it's reused or discharged. What you may discharge, and whether you need a trade waste permit, depends on your local authority.

Common oil-water separators include coalescing plate, vertical gravity and hydrocyclone types, and the right one depends on your flow rate and how much oil your vehicles carry. For heavy oil loads, a triple interceptor pit can be added ahead of the system.

Where water is reused or discharged, tertiary treatment adds further stages. Our containerised wash bay system, for example, combines a coalescing plate separator, media filtration, oil adsorbent granules and chlorine dosing. Sizing starts with the volume of water your wash uses and the conditions your authority sets, so we plan treatment alongside the rest of the bay, not after it. Our water treatment plants can be matched to your wash bay.

Water recycling and wash bay pumps

A closed-loop wash recycles its water, so fresh water is only needed for top-up. At a biosecurity vehicle wash in Tasmania, two MobyDick 400B systems achieved a measured 95% water reuse rate. How much you can reuse depends on your site conditions, how heavily soiled your vehicles are and the treatment in place, so we design recycling in from the start.

Pump selection matters as much as the tanks. Wash bay pumps move water from the recycling tank to the nozzles, and the right pump depends on the flow and pressure your system needs and how much fine solid material is in the water. In our MobyDick systems, submersible MobyPump units return water from the pump chamber for further spraying. We choose pumps alongside the tank size, settling and treatment, so the recycling circuit runs reliably. For pumps beyond the wash bay, see our mining pumps, and for the wider site water picture, our water management systems.

Services and turnkey construction

A wash bay works best when its services are planned in from the start. Power, water, lighting and controls sit outside the spray zone, so they stay clear of water and mud and your team can operate the bay safely. The drip pad is finished to suit your vehicles and drainage, so water returns to the collection point instead of being carried off the bay.

We can deliver the whole bay as a turnkey solution, from design through installation and commissioning, with our project managers, engineers and commissioning technicians. If you'd rather complete part of the works yourself, such as the civil works, we'll work with you on the rest.