Managing Construction Spoil – Why is it so Difficult?
Auditors Call for a Unified Sustainable Approach

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Signed for and on behalf of the following members of the ALGA Auditor Special Interest Group:
Jonathan Thom (Chair)
Warren Pump
Peter Mirkov
Brad May
Julie Evans
Shandel Coleman
Louise Cartwright
Paul Nathanail
Adrian Hall
Jeremy Hogben
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Introduction
In the world of construction and infrastructure development, the magnitude of materials utilised often masks the environmental footprint left behind. One significant, yet often overlooked aspect is the management of huge volumes of construction spoil (surplus excavated soil) generated during infrastructure and building projects. ALGA’s national Auditor Special Interest Group (“Auditor SIG”) includes site auditors from all jurisdictions around the country. The Auditor SIG recently debated key facets of environmentally responsible management of construction spoil (excluding demolition rubble, i.e.,C&D solid wastes). This article delves into these contentious issues and the current state of environmental management in this domain. The Auditor SIG calls for much-needed improvements and a nationally unified approach.

The Scale of the Problem
Currently in Melbourne, 20 million tonnes of construction spoil have or are in the process of being generated by only three infrastructure projects, being the West Gate Tunnel and associated freeway upgrades, the Melbourne Metro Tunnel and the North-East Link. Elsewhere, the current Snowy 2.0 project in NSW will generate 18 million tonnes of construction spoil. To put the quantities of these four projects into perspective, Australians generate more than 67 million tonnes of domestic, commercial and industrial wastes per annum (see the ‘National Waste Policy 2018’). Regulators in some states are well advanced in developing policies for regulation of construction spoil. Somewhat confusingly, however:

• Differences remain across the states in the terminology used to describe ‘construction spoil’. Examples include ‘virgin excavated natural material’(VENM), ‘waste-derived fill’ or simply ‘fill’.
• In both Vic and NSW, even (clean) ‘fill material’ (surplus excavated material) is defined as waste, rather than a resource.
• The Vic government’s Occupational Health and Safety Regulations 2017, and published compliance code in 2019, provide unclear guidance on the supply, transport and re-use of soil containing asbestos fibres. This is despite the 2013 amendments of the ASC NEPM advocating use of stringent health-based screening levels for asbestos fibres in soil for all land uses.

Practitioner Concerns
With these types of issues in mind, in September 2023 the Auditor SIG commissioned a national survey of ALGA members to solicit opinions about current practices for regulation and management of construction spoil. The survey generated 70 responses expressing widespread concerns about the inconsistent state of current practice. Environmental practitioners primarily emphasised a need for improved guidance and practices regarding environmentally responsible spoil disposal and reuse. A summary of some of the issues highlighted by respondents is below:

• Inconsistency in identifying sustainable disposal methods and advocated for enhanced education and compliance checks.
• A need for harmonisation of spoil classification and disposal policies by state regulators.
• Inconsistencies were highlighted for spoil management near state borders, often requiring duplicate classifications.

Respondents also felt that too many sub-contractors in the construction sector pursued profit maximisation when setting unit prices that incentivised artificially higher waste classifications for contaminated soils. Overall, the survey respondents felt that all states and territories should improve their waste classification systems and guidelines. The responses reflected a mix of concerns, suggestions, and alternative approaches to improve waste classification practices. Many emphasised the need for better regulatory compliance, accountability and alignment with best environmental practices.

Auditor Concerns
Jonathan Thom of Nation Partners (Auditor SIG chair) facilitated a panel discussion on spoil management at the October 2023 Ecoforum conference in Melbourne. The panel included senior contaminated land auditors from all States. Echoing the concerns from the survey, the auditors pointed to their observations of widespread non-compliance of classification reports for waste contaminated soils. Although the panel felt that major infrastructure and housing projects (for example) are very likely to have sophisticated processes in place to ensure regulatory compliance, the auditors have also observed that non-compliance was especially evident for non-audited contaminated sites in second tier projects, notably in the property development industry. Disturbingly, the panel also highlighted the potential for systemic non-compliant reuse of contaminated soils. Presumably, as a result of examples of such non-compliance, NSW EPA has considered requiring the movement of VENM to be a licensed activity, to prevent unsuitable materials (including products manufactured from process waste streams) and contaminated soil from being applied to land in avoidance of high treatment or disposal costs. The auditors were clearly concerned that in some industries contaminated soil was too often inappropriately classified, transported and disposed of without proper regard to environmental protection and regulatory compliance. Despite the concerns expressed by auditors, the panel also acknowledged the overwhelming feedback by survey respondents that site auditors should only be involved in waste classification and offsite disposal in certain circumstances (if at all).

A Better Way
The Auditor SIG has called upon environmental regulators across Australia to harmonise policy and regulation for management of construction spoil. They argue that the only rational way is to manage spoil in a more environmentally responsible manner, by embracing the following key principles:

1. Classification of spoil in the building and construction industry should be conducted in the context of the Waste Management Hierarchy, where the avoidance of waste soils is the first and foremost objective.
2. Soil is a natural finite resource. In the interests of a circular economy, and when economically feasible, it should be reused for a beneficial use (after any necessary remedial treatment) rather than “disposed”.
3. “Clean fill” (uncontaminated natural material) should always be considered as a resource and should never be classified as a waste. Reuse of clean fill should be unregulated, including cross border transport.

The Auditor SIG feels strongly that any revised process for spoil classification should, as far as possible, strive for national harmonisation of State-based policy and regulation, albeit in stages. Where feasible and reasonable, auditors argue that construction spoil should be managed according to the following hierarchy:

• Minimisation of spoil generation through design and management;
• Reuse of spoil within the project;
• Reuse of spoil outside the project;
• Treatment then reuse of spoil inside or outside the project; and
• Where reuse is not possible, spoil disposal would be the last resort.

The Auditor SIG feels that processes for classification of spoil should firstly consider all feasible avenues to reuse spoil on the source site or at another suitable site. Only when a classification report shows that spoil reuse is not feasible/permissible should disposal to landfill be recommended. Waste spoil should be sampled, assessed and classified using best practice, risk-based principles in accordance with a nationally agreed framework. On the question of accountability, the auditors suggest that any spoil classification report should be signed by an individual who attests using a legal declaration that the report has been prepared truthfully and honestly, demonstrates satisfactory QA/QC and complies with relevant local regulations and guidance. The Auditor SIG feels it would be best if State regulators could agree on a recommended structure of a classification report, model sampling and QA/QC protocols, definitions of soil domains, and methods of statistical analysis to aid classification.

A Pathway for Change
In the view of the Auditor SIG, unification of spoil management policies and processes could be achieved by preparation of a national ‘Spoil National Environmental Management Plan’ (NEMP). A NEMP should be drafted with guidance from a steering group of affected stakeholders. The first edition of a Spoil NEMP should focus on best practice advice for development/infrastructure projects. Such advice should be complementary with existing legislation/regulation in any State(s). Subsequent editions should encompass harmonisation arising from State-based regulatory updates. In some jurisdictions, adoption of these changes is likely to require corresponding legislative changes. Timelines need to be realistic; this is not a quick fix. A staged approach should be adopted.

Conclusions
Site contamination auditors and environmental practitioners consider that potential mismanagement and misclassification of construction spoil and waste soils represents a significant risk of harm to human health and the environment and unnecessarily consumes valuable landfill airspace. The ALGA Auditor SIG believes that the management processes for construction spoil must undergo a transformative shift with a greater emphasis on consistency of national policy/regulation and environmental sustainability. By adopting innovative reuse options, clearer guidance for stakeholders, and a change in industry mindset, the building and construction industries will be able to further mitigate its environmental impact.

Article Published on 31/05/2024

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