Why this decision matters on Australian worksites
As wash bay volumes increase and asset fleets evolve, the wastewater profile changes: more suspended solids, more hydrocarbons, and more variability day‑to‑day. When the wastewater treatment system no longer “matches” the incoming load, sites feel it immediately—through pump‑out costs, downtime, odour/quality issues, and higher compliance risk. This is exactly why we start every wash bay engagement by clarifying the pathway: trade waste discharge (single‑pass treatment to sewer) or wastewater recycling (treat, store and reuse).
At Everything Water Australia, our Domino wash water treatment systems are delivered under two compliant operating models:
- Single‑pass treatment for discharge to sewer as trade waste, and
- Recycle and reuse systems, where treated water is stored and reused on site.
The two pathways in plain terms
Trade waste discharge
If your premises are connected to sewer and your waste stream can be managed under a trade waste arrangement, trade waste discharge is often the simplest operating model. Our Oil/Water systems have Water Authority approval for discharge to Trade Waste, and we design the pre‑treatment and separation stages to support stable outputs and manageable servicing.
From a cost perspective, trade waste economics are driven by the volume and disposal method. As a real rule‑of‑thumb example we publish: oily water disposal charges may sit around 26–30 cents per litre plus truck time, which can add up quickly (e.g., a scenario of 3,000 L/month can equate to around $1,000/month).
Wastewater recycling (recycle and reuse)
Recycling is a different operating model: we treat wastewater, manage its quality in storage, and reuse it for site operations (such as washdown, wheel wash, underbody wash, irrigation, process water or dust suppression—site dependent). Our Domino wastewater recycling systems are built specifically to preserve and reuse water and can reduce water costs where sites use high volumes. In the recycled water tank, water quality is monitored and disinfected to maintain quality and support Work Health and Safety requirements.
Approvals are also different: if you wish to recycle and reuse your wastewater, the Water Authority may require additional information (including intended use), and recycled water is not potable.
Our decision framework for trade waste vs wastewater recycling
We make the pathway decision by working through five non‑negotiables.
Approvals and “pathway clarity”
Trade waste discharge requires the right agreement/conditions and a system configuration that supports them. Recycling/reuse can trigger additional approval questions because the treated water is being used on site for a defined purpose. We address this early so the design, documentation and commissioning plan align with the pathway you actually intend to run.
Waste stream reality: oil, solids, detergents and variability
We don’t design for a “typical” wash bay—we design for your likely contaminant mix and variability. Our Domino Oil & Water Separator Systems are developed for businesses producing hydrocarbon wastewater containing oil and grease, suspended solids and other pollutants.
Where the wastewater requires additional hydrocarbon polishing beyond gravity separation, we specify combinations such as a vertical gravity separator paired with a high‑performance oil removal cartridge designed to target persistent organic hydrocarbon compounds and emulsified oils.
Volume profile: average day, worst day, wet weather day
Volume is not just a flow rate — it reflects how the site behaves across seasons, rainfall events and peak operating periods. At MET Recycling, the system was engineered specifically to capture and treat contaminated rainwater runoff, preventing it from entering the stormwater network. Treated water is then either reused onsite for dust suppression and wheel wash or discharged to trade waste under controlled conditions. The Domino WWR system was sized using long-term average rainfall data, with capacity and containment allowances for a 1-in-100-year storm event. Instrumentation and control logic manage three distinct operating phases based on rainfall intensity and storage levels, ensuring environmental protection and compliance in all conditions.
Site constraints: space, power, access and operability
We confirm what infrastructure is available and what is realistic to maintain. Our FAQ sets clear expectations: systems are designed and built in Brendale, QLD to current Australian plumbing and electrical standards, with VGS systems available in single or three‑phase depending on the site, and larger systems (ICSEP, Micro and Maxi WWR) using three‑phase components.
Total cost of ownership (not just capital cost)
For smaller generators, a plug‑and‑play separator may be the fastest route to trade waste discharge. For larger generators—particularly industrial wash bays—recycling and reuse can reduce potable water use and lower overall site water consumption and environmental footprint.
We also offer Total Project Management delivery where we take responsibility from design to commissioning and work within firm schedules, supported by compliant documentation (e.g., SWMS and risk analysis).
What “staged treatment” looks like in practice
Wash water rarely gets solved by one component. Our staged approach typically includes:
Pre‑treatment to manage solids and protect downstream stages
When a site’s wash bay contaminants changed, Fulton Hogan’s asphalt/bitumen plant needed an upgrade because contaminants were not being removed to an acceptable level and pump‑out costs were escalating. The accepted solution included retrofitting the pre‑treatment system with a silt screen, proper draining and an oil retention weir, before downstream treatment stages.
Hydrocarbon separation matched to the wastewater type
Our Domino VGS systems operate by controlling fluid velocity and pressure to separate non‑emulsified impurities: high‑density contaminants fall into a sludge retaining area while oil droplets rise and are managed to waste.
Where a broader range of hydrocarbons must be addressed, we specify polishing technologies (e.g., VGS paired with oil removal cartridge) and/or induced cyclonic separation, depending on the wastewater and pathway.
Polishing, storage and disinfection when recycling/reuse is required
In the Fulton Hogan upgrade example, the staged train included flocculation, pH adjustment, dissolved air flotation, an oil water separator fitted with skimmer, secondary filtration to 5 micron, recycled water storage and disinfection dosing. This is the level of staging required when the goal is stable reuse water quality and reduced operational disruption.
Engineer briefing checklist
Before you brief an engineer or request a proposal, capture these essentials. It speeds up concept selection and reduces redesign risk:
- Pathway intent: trade waste discharge, recycle/reuse, or hybrid (reuse plus excess to trade waste).
- Waste stream inputs: oils/grease; solids/silt; detergents; any special contaminants (fuel depot, marine bilge, etc.).
- Volumes and peaks: typical day, peak wash events, wet‑weather influence, shutdown washdowns.
- Site constraints: space for skids/tanks; drainage layout; access for maintenance; power availability (single vs three‑phase).
- Operating expectations: required uptime, who maintains it, monitoring/reporting needs, and any internal WHS requirements.