Wash Bay Installation in Hendra | Trade Waste Compliance

An automotive services business in Hendra needed a new wash bay that met trade wastewater compliance requirements. The site had no existing wash facilities, so the business required council approval before operations could commence. Additionally, stormwater contamination was not an option.

As a result, the business engaged Citi Industries to design and construct a compliant wash bay from the ground up, including drainage, wastewater treatment, and all necessary council approvals.

Project Overview

This project involved new wash bay construction on an existing concrete slab within an industrial shed. Consequently, the scope required significant groundworks, including concrete cutting, excavation for below-ground infrastructure, and full reinstatement of the slab after installation.

The primary constraint involved ensuring all wastewater from vehicle washing would be captured, treated, and discharged to sewer rather than stormwater. Therefore, the project required a combination of collection pits, holding tanks, and an oil water separator to meet Queensland trade waste requirements.

Key scope items included:

Concrete cutting and removal for below-ground tank and drainage installation
1200 litre below-ground holding tank with Class D vehicular traffic lid
600mm collection pit with Class D grate and frame
1000 litre Fox oil water separator with diaphragm pump and control panel
100mm vents to holding tank and sewer line, terminating to atmosphere
20mm RPZD valve with Form 9 lodgement and council registration
Drainage connection to sewer at rear of property
Council inspection of all below-ground works before concrete reinstatement

Challenges

Automotive wash bays in Queensland must prevent contaminated water from entering the stormwater system. Wash water contains oils, fuels, detergents, and sediment that can cause serious environmental harm if discharged incorrectly. Because of this, businesses operating without compliant wash facilities risk enforcement action from both council and the environmental regulator.

This project presented several technical requirements that the team needed to coordinate across multiple trades:

Concrete cutting and removal across the wash area to allow excavation for below-ground tanks and drainage lines
Installation of a below-ground holding tank sized to capture wash water volume, plus trenching for drainage connections
A collection pit positioned inside the wash area to act as the primary water catchment point
An oil water separator system to treat wastewater before discharge to sewer, meeting Queensland Plumbing and Wastewater Code standards
Council inspection of all below-ground earthworks before concrete reinstatement
RPZD valve installation for the water supply, with registration and Form 9 lodgement

What Was Delivered

Citi Industries managed the full scope of works from initial concrete cutting through to council sign-off. The following sections outline each stage of the wash bay installation.

Concrete Cutting and Excavation

Citi Industries began by cutting and removing concrete from the wash bay area. This created access for excavation works, including the pit for the below-ground holding tank and trenches for drainage lines. Subsequently, the team disposed of all removed concrete off-site.

The team sized the excavation to accommodate a 1200 litre below-ground holding tank. In addition, they completed trenching to run drainage lines from the collection pit to the holding tank, then to the oil water separator, and finally to the sewer connection at the rear of the property.

Below-Ground Holding Tank Installation

Citi Industries installed a 1200 litre below-ground holding tank with a Class D lid rated for vehicular traffic. The tank acts as the primary collection point for wash water before it flows through the treatment system.

Furthermore, the team connected two 100mm vents to the holding tank and sewer line. These vents terminate to atmosphere and prevent pressure buildup in the drainage system. Notably, proper venting is a compliance requirement under trade waste regulations.

Collection Pit and Drainage

Citi Industries installed a 600mm collection pit with a Class D grate and frame inside the wash bay. This pit captures water at floor level and directs it into the below-ground drainage system. Importantly, the Class D rating means the grate can withstand vehicle loads without damage.

The drainage line connects the collection pit to the holding tank, then continues to the oil water separator. Once complete, council inspected all below-ground pipework before backfilling and compaction.

Oil Water Separator Installation

Citi Industries installed a 1000 litre Fox oil water separator with a diaphragm pump and control panel. An oil water separator removes hydrocarbons and suspended solids from wastewater before it enters the sewer system.

The diaphragm pump moves treated water from the separator to the sewer discharge point. Meanwhile, the control panel manages pump operation and provides fault alerts if the system requires attention. As a result, this setup meets Queensland Urban Utilities trade waste requirements for automotive wash bays.

RPZD Valve and Water Supply

Citi Industries installed a cold water service with a new 20mm reduced pressure zone device (RPZD) valve. An RPZD prevents backflow from contaminating the potable water supply. Therefore, this valve is mandatory for any water connection serving a trade waste area.

In addition, Citi Industries completed the Form 9 lodgement and council registration for the RPZD. The valve is now registered and compliant for ongoing use.

Concrete Reinstatement and Completion

After all below-ground works passed council inspection, the team compacted the excavated areas in preparation for concrete reinstatement. Next, they poured the wash bay slab with appropriate falls directing water toward the collection pit.

The finished wash bay now provides a contained, compliant area for vehicle washing. Consequently, all wastewater is captured, treated, and discharged to sewer with no risk of stormwater contamination.

Final Outcome

This wash bay installation in Hendra now provides the business with a fully compliant system that meets trade wastewater requirements and council approval conditions. Moreover, the oil water separator system handles wash water treatment automatically, and the RPZD valve is registered for ongoing compliance. As a result, operations can proceed without risk of environmental enforcement.

Wash bay construction completed with council sign-off on all below-ground works
Oil water separator installed and operational for trade waste compliance
RPZD valve registered with Form 9 lodgement complete
Zero stormwater contamination risk from wash operations

Need a Compliant Wash Bay for Your Business?

Citi Industries delivers wash bay installations across Queensland, from initial design through to council approval. If your business needs a wash bay that meets trade waste requirements the first time, get in touch.