Project summary
From February to May 2019 iEnvi was engaged by an inner western Sydney Council to manage a resource‑recovery program that reused road asphalt millings as engineering fill for the construction of new sports fields and courts at a local reserve.
Regulatory context (plain English)
In New South Wales, specialist resource recovery orders and exemptions can allow specific waste materials to be beneficially reused without applying the usual waste‑to‑land or thermal‑treatment controls. These pathways are only appropriate where:
- there is a genuine reuse opportunity, not just a method of disposal;
- the material is fit for the prescribed reuse purpose; and
- there will be no harm to human health or the environment.
Our role and scope
iEnvi provided compliance consulting, site supervision and materials tracking to meet the requirements of the Recovered Aggregate Order 2014 for this project. Key scope elements included:
- Coordinating composite sampling of road millings from the Council’s renewal program (five individual cores per composite) for approximately 80 roads considered for milling;
- Laboratory testing of samples against the chemical criteria prescribed in the Order and the National Environment Protection (Assessment of Site Contamination) Measure (NEPM (ASC)) for recreational/public open space settings;
- On‑site supervision and chain‑of‑custody tracking of material during a 13‑week program; and
- Organising compliant material into batches and documenting reuse as engineering fill for the reserve development.
Sampling, batches and volumes
Sampling protocols followed the Order’s expectations (including the minimum frequency of samples per tonnage where applicable). Approximately 19,755 tonnes of asphalt millings, milled from 56 roads, were organised into eight compliant batches and transferred for reuse as engineering fill at the sportsfield reserve.
Outcomes and benefits
- All tested materials met the chemical acceptance criteria under the Recovered Aggregate Order and were assessed against NEPM (ASC) criteria for recreational open space and deemed suitable for use at the reserve.
- The reuse program reduced the need for excavation disposal, saved on clean fill import requirements and avoided associated environmental management costs during the sportsfield development. The client estimated the program delivered substantial cost savings (described in the original project records as several million dollars in avoided road disposal fees, plus approximately $600,000 in reduced clean‑fill and environmental management costs).
- Reuse recycled a significant quantity of material (≈19,755 t), supporting sustainable construction practice and circular resource use within Council works programs.
Practical considerations for councils, developers and contractors
- Not all milled asphalt is automatically suitable for reuse. Compliance testing and fit‑for‑purpose assessment against both recovery orders and site‑contamination criteria is essential before reuse.
- Early engagement with an environmental consultant and suitable laboratory testing saves time and reduces unexpected disposal or remediation costs during construction.
- Clear chain‑of‑custody, batch tracking and documented decision records make projects auditable and reduce commercial and regulatory risk.
- Where material is proposed for public open space, apply conservative assessment criteria (for example NEPM (ASC) recreational settings) and document risk management measures for placement, segregation and future land use considerations.
Key takeaways
- Resource recovery orders can enable safe, cost‑effective reuse of materials like asphalt millings when applied correctly.
- Comprehensive sampling, independent testing and professional supervision are required to demonstrate compliance and protect human health and the environment.
- Reuse can realise significant savings in disposal and construction costs while supporting sustainability and circular‑economy objectives.
Contact iEnvi
To discuss whether recovered aggregate reuse is appropriate for your project and to reduce construction and disposal costs while managing regulatory risk, contact iEnvi on 13000 43684 or via our contact page.