Quote To Live By: “Don’t count the days, make the days count”-Cassius Clay


  • Environmental auditing, assessment, and management, including sampling and analytical methods, and legislative requirements
  • Landfill assessments and audits, including leachate and landfill gas management
  • Risk assessment and landfill rehabilitation
  • Design of landfill gas protection measures, venting barriers and building barriers
  • Remediation of contaminated soil and groundwater including LNAPL in fractured rock

  • Full Profile

    Stephen is a Chartered Professional Environmental Engineer with over 20 years’ experience in remediation and contaminated land investigations. He has highly developed engineering skills in environmental audits, contaminated sites investigations, landfills, report writing, peer reviews, project management and project technical direction.

    Stephen’s experience encompasses contaminated sites and landfill investigations in Australia and Papua New Guinea, including conducting large scale complex contaminated land investigations and remediation programs on petroleum and petrochemical sites, landfill gas risk assessments and environmental risk assessments for existing and former landfills.  He has conducted Statutory Environmental Audits under Section 53V and 53X of the Environment Protection Act, Victoria 1970, of various sites including former industrial sites being redeveloped for more sensitive landuses; and landfills (construction, operations, rehabilitation and aftercare management). Additionally, his expertise includes environmental chemistry, remediation technology feasibility assessment and implementation, source identification, and conducting complex site investigation programs.  Stephen has provided expert opinion in relation to landfill gas risk assessments and protection measures for closed landfill developments.  He is actively involved with the EPA Auditor landfill specialist working group meetings, and has presented published papers at international conferences in relation to contaminated land and landfill assessments.   


    • Bachelor of Engineering (First Class Honours), major in Environmental Engineering and minor in Geotechnical Engineering, RMIT University (1996)

    Certifications and Training

    • EPA Victoria Appointed Auditor (Contaminated Land), 2015 to present
    • Chartered Professional Engineer with the Engineers Australia, from 2009
    • Registered Professional Engineer (Environmental – General) with Engineers Australia, from 2009
    • Member Engineers Australia, from 2005



    Stephen has served as the Auditor, Auditor Assistant, and Project Manager on the following 53X and 53V audits.

    53V Audit of former service station.


    Stephen was the appointed Auditor for this project, which involved the following:

    • Preparation of the Audit Scope for EPA submission;
    • Review of the previous CUTEP submission and post-remediation monitoring reports;
    • Review of groundwater trends and compliance with the requirements of the Groundwater Quality Management Plan (GQMP);
    • Assess the risks to the beneficial uses of the environment associated with the residual groundwater contamination;
    • Prepare a s53V Environmental Audit report;
    • Liaise with EPA regarding recommendations of Audit report, including cessation of ongoing groundwater monitoring and extent of Groundwater Quality Restricted Use Zone.

    53X Audit of former cattle saleyards in regional victoria.


    Stephen was the appointed Auditor for this project, which involved the following:

    • Preparation of the Audit Scope for EPA submission;
    • Review of all previous site assessment reports, and conduct a data gap assessment to identify what additional assessment was needed at the site;
    • Work with the client and site assessment consultant to develop a work scope investigation of groundwater and soil vapour risks associated with a petroleum plume emanating from the neighbouring site;
    • Liaise with the client, Council and EPA regarding the likely Statement of Environmental Audit conditions and the implications and constraints with site development;
    • Prepare an Auditor determined Clean Up To Extent Practicable (CUTEP) report;
    • Prepare a s53X Environmental Audit report;

    53V Audit of current Petroleum Refinery.

    Auditor Assistant

    Stephen was involved in all facets of the project, including:

    • Preparation of the Audit Scope for EPA submission;
    • Review of the assessors workplans and reports;
    • Technical review of Clean Up Plan, and review of efficacy of proposed remediation methods of LNAPL in fractured rock aquifer;
    • Review of dissolved phase groundwater contamination data to assess the likely source of chlorinated hydrocarbons and petroleum contamination.  Stephen utilised his expertise in interpretation of laboratory data, by comparing the concentrations of TRH and chlorinated hydrocarbons to conduct a mass balance to assess whether the chlorinated hydrocarbons accounted for the TRH concentrations.
    • Participation in update meetings with EPA, the client and assessor;
    • Audit report preparation for auditor review, including preparation of the risk assessment methodology, interpretation of description of the nature and extent of contamination, and drafting of recommendations.

    53V Audit of operational landfill -Murrindindi Council Alexandra Landfill (multiple years)


    Stephen was involved in all facets of the project, including:

    • Review of site assessor’s reports, with respect to the nature and extent of contamination, and also assessing the how representative the data was of the environmental condition of the site;
    • Review trends in groundwater contamination data, and what the impact of the contamination was on existing and likely beneficial uses of groundwater;
    • Identify data gaps that were present in the groundwater monitoring network, and making recommendations for further assessment work within the 53V Audit report; and
    • Conducting an operational audit of an active landfill, including all elements of potential environmental impact (soil, groundwater, surface water, air, noise, litter, licence compliance, fire risk, etc.).

    Multiple Clients


    Stephen has undertaken the following Auditor roles on landfills and other sites:

    • 53V Environmental Operations Audits for landfills;
    • Auditor verification of a wetlands treatment system concept design for landfill leachate in south-western Victoria.
    • Design review of landfill Rehabilitation Plans, including Capping Design and Aftercare Management Plan for several sites.
    • Auditor verification of a Hydrogeological Assessment for a composting facility.
    • 53V Environmental Audit of the construction of a new landfill cell;
    • 53V Environmental Audit of the construction of a landfill cap;
    • Auditor verification of a landfill Rehabilitation plan inclusive of a phytocap.
    • 53X Audit on former garden supplies centre and concrete batching operation.

    53X Audit of Former School

    Auditor Assistant

    The site assessment and audit process identified the following issues, which required remediation works to be conducted to restore beneficial uses:

    • Former Underground Storage Tanks and petroleum soil contamination; and
    • Asbestos Cement Sheeting fragments scattered through the soil profile as a result of building refurbishments conducted previously.

    As the Auditor Assistant, the tasks he performed relevant to Environmental Auditing of contaminated land included:

    • Review of the Site Assessor’s workplans;
    • Review of the Site Assessor’s site assessments, Remediation Action Plan, and remediation validation reports;
    • Conducting site inspections during site assessment and remediation phases; and
    • Drafting the 53X Environmental Audit report.

    53X Audit of Former Shell Grit Mining Area and Potato Farming

    Auditor Assistant

    This project involved a 53X Audit of a site subject to an Environmental Audit Overlay, due to the previous use of the site for a shell grit mining operation and potato farming area.

    Stephen applied the principles and methods of auditing to assess whether the site was suitable for any beneficial use.

    53X Audit of A Former Service Station Site

    Auditor Assistant

    Stephen was involved in the review of the assessor’s workplan and site assessment program.

    In addition, Stephen has been Project Manager and lead technical report writer on many contaminated sites projects as the assessor, which were subject to Statutory Audit (Contaminated Land).

    Landfill, Waste Management & Gas Risk Assessment Experience

    Stephen has extensive experience in environmental engineering assessments and design associated with former and operating landfills, including landfill gas assessments, design of landfill gas control measures, leachate fate and transport and leachate treatment studies.  Additionally, Stephen has a thorough understanding of the regulatory measures applicable to landfills in Australia and the UK.

    Confidential Waste Facility

    Lead Consultant

    Stephen served as lead consultant for the client applying for Planning Permit and EPA Works Approval for a contaminated soil treatment and recycling facility in the Geelong region.  His role for this project included:

    • Design and implementation of a pilot trial of a soil treatment biopile to allow measurements of odour, noise and vapours.
    • Coordination of site programs for obtaining the necessary environmental data for Works Approval application.
    • Direction and review of the treatment process design report for the soil treatment system, and environmental monitoring data (noise, air quality, groundwater) and associated control measures.
    • Attended meetings with Council and EPA as the client’s technical advisor.
    • Attended the community consultation meeting as the client’s technical advisor to discuss the proposed facility and answer questions from the public.

    Multiple Clients

    Tier I and Tier 2 Risk Assessments

    Stephen conducted Tier 1 and Tier 2 risk assessments for the risk of gas migration from waste sources including operating and former landfills, and dairy waste effluent disposal.  The approaches adopted in these risk assessments were based on the UK Guidance on landfill gas risk assessment and management, including the use of Conceptual Site Models, Gas Screening Values, and Source-Pathway-Receptor analysis.  He also recently presented at a peak body seminar on the recently released EPA Victoria Closed Landfill Guidelines with EPA, focussing on the Brookland Greens and Loscoe case studies.

    Stephen has conducted numerous landfill gas risk assessments, including: Sunshine Coast landfill, Caloundra, QLD; Anglesea landfill, Victoria; Alvie landfill, Victoria; and Diary waste effluent disposal into Karst Limestone aquifer.

    Landfill Leachate Groundwater Assessments – Multiple Clients

    Lead Consultant

    As a consultant, Stephen has conducted numerous landfill leachate impact assessments for operating and closed landfills, incorporating complex hydrogeological settings.  He has a thorough understanding of the geochemistry associated with landfill leachate generation, migration, transformation and attenuation. In addition, his experience includes conducting feasibility studies for leachate treatment, including assessment options such as evaporation ponds and wetlands treatment.

    Landfill Environmental Risk Assessment and Environmental Monitoring Program -Multiple Clients


    Conducted Environmental Risk Assessments (ERAs) and prepared Environmental Monitoring Programs (EMPs) for operating landfills, based on the Joint Australian/New Zealand Standard, AS/NZS ISO 31000:2009, Risk management — Principles and guidelines.  The ERAs considered risks to land, groundwater, gas migration, surface water, and landfill license operational issues such as noxious weeds, vermin, and waste types, with the EMPs prepared to monitor these elements in accordance with the risk profiles presented.

    Landfill Gas Mitigation Design – Confidential Client

    Project Manager and Engineer

    Project manager and design engineer for the redevelopment of a former landfill site for future residential and commercial landuse.  Stephen has prepared and implemented the site assessment program of works to obtain site data on the concentration and flux of landfill gas on the site, including conducting a risk assessment based on the Gas Screening Value approach.

    He has also prepared conceptual designs of gas mitigation measures, including landfill capping, gas collection and venting, and gas barriers for the proposed development.

    Contaminated Site Assessments & Remediation Experience

    Stephen has conducted well over 100 contaminated site investigations across Australia, primarily in Victoria.  He has extensive experience in the geology of Victoria, particularly in fractured rock aquifers in Melbourne, and the various geologies in south-western Victoria.

    Baseline Environmental Site Assessment for Property Transfer – VIC and NSW Sites

    Project Manager

    This $10M project required the assessment of the environmental quality of soil, groundwater, sediment and surface water quality of multiple petrochemical facilities in NSW and Victoria to meet the requirements of the Environmental Indemnity Deed.  In this role, which continued for five years, Stephen was responsible for:

    • Reviewing all previous Environmental Site Assessments (ESAs) and studies that had been conducted at the Victorian sites;
    • Developing the proposed scope of works, taking into consideration the time period since previous investigation had been conducted, and identifying data gaps;
    • Conducting extensive site history reviews consisting of review of likely contaminants of concern (extensive), waste disposal practices, chemical processes and waste streams, and interviews with site operators.
    • Implementation of field investigation program, including coordination of a large team of staff in a range of technical field and data management activities;
    • Interpretation of chemical data, including differentiating the source of contaminants based on chemical breakdown products of chlorinated hydrocarbons;
    • Interpretation of complex hydrogeological setting, based on rock core logs for multiple aquifers, and groundwater analytical results;
    • Interpretation of chromatogram profiles with the assistance of an environmental chemist to identify potentially unknown chemicals in the TPH scan;
    • Report writing involving a multi-disciplinary team with specialists in: drafting, environmental chemistry, human health risk assessment, and hydrogeology;
    • Project management and primary client contact for the entire portfolio of NSW and Victorian sites being sold.

     Former Dry Cleaning Facility and Service Station

    Project Manager

    Stephen was the Project Manager for the demolition and bulk remediation (fuel storage infrastructure, liquids and contaminated soils).  Also for this site, Stephen managed and co-authored a Phase 1 ESA, Phase 2 ESA relating to contaminants of concern including chlorinated hydrocarbons and petroleum hydrocarbons.  He managed an off-site groundwater monitoring program and assisted in the preparation of a Quantitative Human Health Risk Assessment.  He also prepared a Remediation Options Analysis for the site, including the implementation of a mobile Multi-Phase Extraction program to remediate LNAPLs at the site.  This site was also subject to a Statutory Environmental Audit at all stages of investigation and remediation. Project value: $2M

    Environmental Site Assessment and Remediation for a Former Petroleum Depot

    Project Manager

    Stephen served as the primary point of contact for the client and other stakeholders including the Environmental Auditor, off-site land owners, and off-site utility owners (such as the local water authority whose asset was impacted by the contamination).

    This site was a complex petroleum source site, with contamination extending beyond the site boundaries and comingling with a petroleum plume from an adjacent site.  The site is subject to an EPA Clean Up Notice.  Stephen prepared the scope of the investigation program to delineate the soil and groundwater contamination, and prepared the overall remediation strategy for the site, consisting of combined soil vapour extraction and groundwater dewatering.

    The project included:

    • Sampling plans and interpretation of analytical data for soil, groundwater and soil vapour.
    • Environmental chemistry and forensics to identify the likely demarcation between a joint LNAPL plume.  This involved interpreting LNAPL speciation data, dissolved phase groundwater contamination, historical groundwater flow directions, and site history information.
    • Groundwater remediation: he conducted remediation feasibility assessment (screening) for various technologies; implemented a soil vapour and groundwater pump and treat remediation trial; coordinated the installation and commissioning of a groundwater remediation system; undertook performance monitoring, system optimisation and reporting.
    • Soil remediation: designed and implemented a soil vapour extraction biopile to remediate the source zone of contamination in the unsaturated zone.

    Project Value: $3M (including remediation costs)

    Environmental Site Assessment and Remediation Strategy for Petroleum Terminal Subject to an EPA Clean-up Notice – Yarraville Terminal

    Project Manager

    Responsible for the project management for the preparation of a Clean-up Plan and further field investigations to characterise the site pollution.  This role required a detailed understanding and management of the technical requirements of the project for a site with complex interaction of fractured rock and alluvial sediments, and a preferential groundwater discharge path to sewer.  The site also included assessment of DNAPL, originating from a neighbouring site.

    Project Value: $2M (for this stage)

    Environmental Site Assessment and Remediation for a Former Hat Manufacturing and Textile Factory

    Project Manager

    The scope of work for this project consisted of a soil and groundwater investigation, and the development and implementation of a Remediation Action Plan (RAP) for the remediation of contaminated soil. In addition, a site management plan (SMP) was required for the management of residual contaminated soil remaining on site, post-development.

    To achieve a sustainable final ground condition of the site, it was necessary to consider several aspects of the site.  A large portion of the site had historically been contaminated by mercury waste in the uppermost 1 m of fill underlying an old pavement layer.  This contaminated fill material presented potential risks to future occupiers of the site under a more sensitive land use scenario, and a potential risk to the environment from leaching of mercury to groundwater.  In addition, a significant portion of the site was subject to heritage restrictions, which required some buildings and features to remain. Further, the client’s proposed development included a basement car-park which meant that a large volume of contaminated fill material was required to be removed from site.

    Stephen’s expertise in environmental chemistry was used to determine the speciation of the mercury encountered on site, which was an important consideration in assessing the risk to groundwater contamination and vapour risk to future occupants.

    Project Value: $1.5M (including remediation costs)

    Environmental Site Assessment and Remediation for a Former Quarry/Landfill and Technical College

    Project Manager

    The scope of work for this project consisted of a Phase 1 Environmental Site Assessment (desktop ESA including site history documentation), a Phase 2 ESA (soil and groundwater investigation), and the development and implementation of a Remediation Action Plan (RAP) for the remediation of contaminated soil.

    The site had formerly been a quarry and landfill which was historically developed as a technical college. The client proposed to develop the site with low and medium density residential housing.  In developing the RAP, a balance had to be obtained between the high cost of soil remediation with the need to protect future occupiers of the site from potential health hazards associated with the soil contaminants. A solution was developed in consultation with the client and the Auditor to remove all contaminated soil to a depth of 0.5m, install a warning barrier, and then backfill with suitability clean fill.

    The RAP met the objectives of the stakeholders in that it:

    • Protected the future occupiers of the site from exposure to contaminated soil;
    • Allowed the development of the site in a sustainable manner and allowed the removal of derelict buildings and contaminated soil from the local landscape;
    • Provided a cost-effective means of remediation for the client.

    Project Value: $1M (including remediation costs)

    Remediation of a former Service Station – Newstead, Tasmania

    Project Manager

    This project involved the remediation of residual minor LNAPL and dissolved phase hydrocarbon contamination at a former service station site, where the groundwater contamination extended off-site.  Various oxidants were selected for injection into the semi-confined aquifer at depth, using a pulsed injection method under pressure.  The program of injection included more aggressive oxidants initially, followed by slower release oxidants (persulphate) to provide a sustained oxidation medium for the contaminants.  The works resulted in a completion of the required remediation works at the site.

    Project Value: $1M

    Scoping of Environmental Site Assessment for Werribee Employment Precinct Department of Planning and Community Development – Victorian State Government

    Project Manager

    Stephen prepared an environmental site assessment investigation plan for a site with numerous contaminating land uses, including agricultural chemicals, animal carcasses, landfill and radioactive tracer dyes used in bovine health research.

    Former Quarry and Landfill Redevelopment in Oakleigh South, Melbourne

    Project Manager and Technical Lead

    This project included the assessment of subsurface conditions, including the extent and type of landfilled waste, waste slimes (sand washing by product), groundwater conditions, soil, sediment, surface water and landfill gas.  Stephen’s expertise was applied in the following areas:

    • Preparation of a data gap report and Conceptual Site Model;
    • Scoping and conducting ESAs;
    • Conduct of a landfill gas risk assessment, including interpretation of landfill gas data (concentration and flow), further development of the Conceptual Site Model, and calculating the Gas Screening Values;
    • Design of conceptual landfill gas protection measures based on the ‘Characteristic Situation’ approach and the GSV calculations for future residents and neighbours, including boundary venting system and building venting and membrane systems;
    • Preparation of a Site Remediation Strategy for Auditor approval.  The purpose of this documents was to provide Council and EPA with confidence that the site could be successfully remediated and redeveloped;
    • Liaison with the separately appointed Environmental Auditor, including providing technical and legislative input at meetings with the Auditor, EPA and Council.

    Other Selected Environmental Site Assessments and Remediation Projects – Various Clients

    Project Manager

    Other contaminated site remediation and investigation projects Stephen has been Project Manager and primary technical report writer have been:

    ESA and remediation works for a former sheep dip site being developed for residential dwellings which was contaminated with arsenic.

    Groundwater investigation program for a manufacturing site with a toluene LNAPL plume and dissolved phase chlorinated hydrocarbon plume.

    Site investigation, remediation and ongoing groundwater management strategies and monitoring conducted in waterfront properties of the Docklands precinct, involving extensive gasworks waste contamination.

    Project Manager for ESA and Remediation works for operating and former telecommunications exchanges and depots as part of a national divestment program for Telstra (over 100 sites).

    ESAs for numerous service station sites for major petroleum retailers, including managing a program of contaminated site investigations and remediation.

    Acid Sulphate Soils:  sampling, analysis and reporting associated with Coode Island Silts in the Docklands development area.

    Environmental Site Assessment for former farmland with dieldrin and DDT breakdown products contamination.


    Statistical Analysis

    Statistical Interpretation of Groundwater Contamination Trends Remediation Projects

    Technical Report Writer

    Stephen has applied his statistical skills to interpretation of groundwater contaminant trends, following active remediation works.  This has included using the Mann-Kendall method for assessing petroleum hydrocarbon concentrations in groundwater, and preparing Groundwater Quality Management Plans specifying the statistical tests required to demonstrate the stability of groundwater plumes.

    Cost Modelling

    Probabilistic Cost Modelling of Remediation Projects

    Project Manager

    Stephen has obtained experience in using probabilistic cost modelling techniques for contaminated sites remediation projects to provide a likelihood of certain costs being incurred.  This is typically represented by a range of Confidence Limits (50%, 80%, 95% and 99%) associated with the remediation costs.  The methodology assists in identifying assumptions associated with the risks and includes an estimate of the corresponding probability of occurrence.

    The probability of occurrence and the range of anticipated costs are then simulated using a statistical method known as Monte-Carlo simulation to aggregate the total liability. The outcome can be presented in terms of a graph and/or tabulation representing the Confidence Limit vs the Cost, so that the relationship between uncertainty and cost can be easily visualised and understood.

    This method allows the client to better understand the uncertainties in remediation costings, and also allow more informed planning and/or financial instruments for managing financial risk (such as cost sharing between buyers/sellers, or insurances).

    Stephen has applied these techniques to several complex divestment sites for a major petroleum company.

    Environmental Forensics

    Various Projects

    Project Manager and Technical Report Writer

    Stephen has previously conducted environmental forensics investigations for the following scenarios.

    Source identification of mixed benzene and chlorinated hydrocarbon plumes in groundwater.  This involved compiling the following lines of evidence into a concise report which met the objectives of an Environmental Indemnity Deed:

    • Site history of two adjacent chemical production facilities over 50 years of operation, including site interviews with employees;
    • Obtaining and interpreting laboratory analysis for non-standard organic chemicals previously used on one of the facilities;
    • Calculating and spatial plotting of ratios of various chemical present in groundwater;
    • Historical time series analysis and interpretation of standing water levels and groundwater flow contours;
    • Fate and transport considerations, including degradation rates of the key chemical of concern;
    • Hydrogeological interpretation and limitations of fate and transport understanding in fractured rock aquifers;
    • Interpretation of the spatial extent of soil and groundwater contamination.

    Source identification of LNAPL plume.  This involved compiling the following lines of evidence into a concise report which met the objectives of an Environmental Indemnity Deed:

    • Site history of a pipeline facility and bulk storage facility;
    • Interpretation of groundwater flow regimes and limitations of fractured rock flow;
    • Obtaining ‘fingerprinting’ report for various samples of the LNAPL on a transect through the plume;
    • Interpretation of ratios of various chemicals within the LNAPL with respect to the relative weathering of the product (and hence distance from the source release).

    Infrastructure/Environmental Management

    Wind Farm – Confidential Client

    Client Site Engineering Representative

    Stephen completed a site engineer role on a wind farm development within Victoria.  Within this role, he reviewed construction management documentation (QA, OHS and EMP project documents) prior to construction commencement on site.  The site based role, was full time for a period of 6 months, included monitoring and auditing the head contractors’ adherence to their design documentation and project management plan.  Where deviations from the project documents were found, Stephen coordinated a Proof Engineering review of the proposed changes.  In addition, he assessed contractor variation claims and extension of time claims for the client as the owner/operator of the wind farm.

    Construction/Project Management Aspects

    Stephen’s experience and skills include program management of construction projects (wind farm, construction projects, water supply dam embankment stabilisation project, and site remediation projects incorporating civil engineering components). Within the construction industry he has taken on the responsibilities of Site Engineer and Project Manager of a diverse range of projects. Stephen has also been responsible for design management and design reviews as the Project Manager of external design teams and estimators. Within this area, he was responsible for budget and contract control, ensuring contractual obligations are adhered to; assessing contractor variation assessments and progress claims.

    Selected Publications and Presentations

    S Cambridge and C O’Farrell. 7th International Congress on Environmental Geotechnics. (November 2014).  Preparation and presentation of paper titled ‘Hydrocarbon Mass Estimation: Methods of Calculation and Relevance to Risk Assessment’.

    S Cambridge and S Richards. 2013. Poster presentation at the 2013 International Clean Up Conference in Melbourne, titled ‘Standards of Proof for Contaminated Sites Investigations, Balancing Risk and Uncertainty’.

    Assisted with the development of the Industrial Waste Management Policy – Waste Acid Sulphate Soils whilst working at EPA, and poster presentation on the Contaminated Land Environmental Audit system in Victoria.