Selected EI projects in Contaminated Land Management

Land Remediation Urban Renewal – Mortlake, NSW

EI prepared the Remedial Action Plan (RAP) and subsequently supervised the staged remediation, validation and environmental management works for the urban renewal of Mortlake Point. This was a 3 hectare (ha) site comprising over 35 commercial, industrial and older style fibro/brick houses and many below and above ground storage tanks within a former paint factory.

The RAP also considered Acid Sulfate Soils along the foreshore, the potential for gasworks waste in site fill and the presence of badly damaged asbestos sheeting and possible friable asbestos in pipework within the building fabric.

Remediation and validation of soil, soil vapour and groundwater is currently being conducted to enable the land to be used for multi-storey residential blocks with basement car parking and foreshore open space, following independent audit by a NSW EPA accredited site auditor.

Value Added / Beneficial outcomes for Client: EI used its knowledge of the extensive number of chemicals used in historical paint factory operations to develop a conceptual site model for the complex, fractured bedrock environment, which allowed greater efficiencies in characterisation, remediation and validation of the site. EI also developed asbestos removal and environmental control plans to facilitate development consent.

very dirty site

Site Remediation & Environmental Management – Zetland, NSW

With historical industrial uses including whitegoods manufacturing and metal foundry operations, the 2.5 ha former whitegoods manufacturing site was subject to impacts including chlorinated solvents and had been notified to the NSW EPA under Section 60 of the Contaminated Land Management Act 1997.

EI’s work included data gap closure investigations, active remediation & validation of impacted soil and groundwater, vapour intrusion modelling, natural attenuation assessment and development of Stage-specific EMPs for commercial, residential and recreational open space redevelopment.

The natural attenuation assessment is currently ongoing and the existing groundwater monitoring dataset appears to support the feasibility of Monitored Natural Attenuation as an appropriate remediation strategy for low-level, residual groundwater concentrations.

Value Added / Beneficial outcomes for Client: Assisted in making the site suitable for the intended land uses, with Site Auditor sign-off and Council approval, which enabled project stages to be constructed sequentially with minimal delay. Also maintained communication with NSW EPA in compliance with regulatory requirements.

Remediation Planning – Land Redevelopment, Camellia, NSW

This 6000 square metre former industrial site, which included a former James Hardie factory, Camellia Chemical factory and a solvent drum recycling facility, was to be redeveloped for commercial, residential and recreational uses with basement car parking.

With the goal of making the site suitable for the proposed land uses EI assessed soils, groundwater and geotechnical conditions and developed a preliminary RAP for the on-site encapsulation of over 70 000 cubic metres of buried, asbestos-containing materials and localised, TPH/PAH-impacted clinker waste.

The remediation strategy included onsite bio-pile treatment of soils impacted with petroleum and VOCs. EI also provided technical inputs to the landfill cell design concept.

Value Added / Beneficial outcomes for Client: EI progressed the site characterisation process to enable RAP revisions and to better inform related disciplines and consenting authorities during the review and approval process.

Selected EI projects in Acid Sulfate Soils Assessment / Management

Acid Sulfate Soil Management – Cooks River Bank Rehabilitation, Marrickville, NSW

As part of the NSW EPA’s initiative to rehabilitate aging river bank shoring, a remediation program was conducted along a 750m stretch of the Cooks River, to improve the amenity and aesthetics of the foreshore and to enhance the ecological function of the river.

Based on the findings and recommendations of previous Acid Sulfate Soil (ASS) Assessments, EI developed and supervised an ASS Management Plan (ASSMP), to minimise potential impacts associated with the disturbance of ASS during the bank remediation works.

The works included calculation and specification of required liming rates to neutralise expected acidic conditions and the monitoring of groundwater and surface water quality, to assess potential impacts during the works program.

Value Added / Beneficial outcomes for Client: As a direct result of the work conducted by EI, the Client was able to identify the location of potential and actual ASS in advance of excavation works. With the guidance provided in the ASSMP these materials were treated immediately after excavation, thereby preventing acidification of groundwater and leachate impacts to the river ecosystem.

Acid Sulfate Soil Assessment and Management Plan– Botany, NSW

In support of a Development Application (DA) to Botany City Council, an ASS assessment was conducted to evaluate the potential for acid sulfate soils and consider the need for management action to prevent leachate generation during the residential redevelopment of an existing commercial/industrial site.

Through targeted soil sampling, field-based testing and laboratory analysis, ASS were confirmed to be present, which triggered the preparation of a site-specific ASSMP to inform on the required measures and procedures to be undertaken in the impacted area for the prevention/control of acid leachate generation and the protection of site structures and the surrounding environment.

The ASSMP also included details on focussed soils, surface waters and groundwater monitoring, as well as a description of the contingency procedures to be implemented in the case of failure of the ASS management strategy.

Value Added / Beneficial outcomes for Client: Achieved consenting authority approval of the DA for the proposed development.

Voula field filtration

Selected EI projects in Geotechnical Engineering Services

Residential Development, Camperdown, NSW

Redevelopment of a 7000 square metre site including construction of nine residential buildings up to seven-storeys high over two basement levels. Site challenges involved uncontrolled fill up to 6 m depth under the building footprints, varying geology across the site and proximity to two major roads, which required direct consultation with NSW RMS.

Investigations involved borehole drilling, test pit excavation, site mapping and laboratory testing. EI formulated a detailed site model and provided design advice for foundations and basement retention. EI also carried out detailed design of a soil nail wall approximately 150 m long and up to 8 m high and underpinning of a neighbouring eight-storey structure.

Value Added / Beneficial outcomes for Client: Achieved …..

St Basils Aged Care Facility – Randwick, NSW

EI provided geotechnical services for the construction of an aged care facility comprising 73 independent living units and 113 residential aged care beds. The site was underlain by a layer of aeolian sand deposits up to 12 m thick with elevated groundwater levels.

Basement retention had to be designed to limit ground movement, which had the potential to damage heritage structures adjacent to the excavation. EI’s team reviewed existing geotechnical data for the site and designed working platforms and temporary roadways for construction plant.

EI supervised the successful installation of a contiguous shoring pile retention system and foundation piles for the development.

Value Added / Beneficial outcomes for Client: Achieved …..

Residential Subdivision – Horningsea Park, NSW

This project involved a detailed geotechnical assessment of a 12 ha residential subdivision on a flood-prone site. The area was also subject to high salinity risk with environmentally sensitive vegetation along an existing creek line. Intrusive investigations were by mechanical auguring, test pitting and dynamic cone penetrometer and salinity testing.

EI’s report included recommendations for design and construction of foundations, retention systems, pavements and excavation support considering the presence of saline and dispersive soil types. Advice was provided on management of saline soils in accordance with the Western Sydney Salinity Code of Practice prepared by the Western Sydney Regional Organisation of Councils (WSROC).

Value Added / Beneficial outcomes for Client: Achieved …..

Residential Development – The Entrance, NSW

EI assessed soil and rock conditions in order to provide a conceptual site model for input to basement retention and foundation design. The site was underlain by the Patonga Claystone formation, which has a tendency to produce sliding failures on siltstone bands at low angles of repose.

EI worked with the structural engineers for this project to design a retention system, which appropriately managed the risk associated with poor ground conditions in a cost-effective manner.

Value Added / Beneficial outcomes for Client: Achieved …..

Mixed Use Development – Mascot, NSW

EI assessed subsurface soil, rock and groundwater conditions at a current industrial site for redevelopment as a nine-storey commercial building over one to two levels of basement parking. Key geotechnical constraints for the site included the presence of deep soil associated with the Botany Basin sands and the proximity of the development to the Airport Link Rail Tunnel.

EI’s involvement is to include detailed geotechnical investigation, finite element analysis and liaison with Sydney Trains to demonstrate that the proposed development would not impact the Sydney Central to Airport rail tunnel.

Value Added / Beneficial outcomes for Client: Achieved …..

UNSW Mechanical Engineering Building – Kensington, NSW

Geotechnical supervision of the demolition and construction of a new teaching and workshop facility for the Department of Mechanical and Manufacturing Engineering at the University of New South Wales. EI’s involvement included the review of structural designs for footings and shoring, the supervision of piling and on site assessment of working platform design.

Specific project challenges included the presence of historic foundations, maintaining the stability of neighbouring structures and a stepped rock profile across the site.

Value Added / Beneficial outcomes for Client: Achieved …..

Residential Development – Dee Why, NSW

EI carried out a geotechnical assessment and slope risk assessment for a residential development in Dee Why, NSW. The proposed development straddled a 4 m high waterfall associated with an historic drainage line.

The assessment included drilling of 5 boreholes, laboratory testing of collected soil samples and a semi-quantitative rock slope risk assessment according to Australian Geomechanics Society Guidelines.

The geotechnical assessment of the site was carried out under tight site access restrictions and with environmental controls in place to prevent the possibility of an environmental incident caused by drilling near a watercourse.

Value Added / Beneficial outcomes for Client: Achieved …..

Selected EI projects in Waste and Landfill Investigation Services

Waste Soils Management – Mine Rehabilitation, Mount Keira, NSW

EI managed the excavation, waste classification and off-site disposal of embankment materials as part of a Mine Rehabilitation Project. EI’s involvement included in-situ assessment of mined overburden soils, excavation and stockpiling of slag filling and naturally-occurring PAH-rich soils, prior to waste classification testing and landfill disposal.

Landfill disposal volumes and costs were minimised by separating, large volumes of validated soils for reuse as filling on a nearby residential estate, in accordance with a site-specific RAP and with NSW EPA Site Auditor approval.

Value Added / Beneficial outcomes for Client: Through strategic waste segregation and careful waste classification assessment and material movement tracking, EI enabled the Client to comply with current relevant waste regulations and recover over 90% of the waste soils for approved reuse on a nearby residential estate, while minimising waste disposal costs for impacted soils disposed to licensed waste landfill.

Routine Waste Classification Assessment and Reporting – Waste Transfer Site, St Peters, NSW

As part of a long-term, waste soil quality monitoring programme at an EPA-approved, former, waste transfer station located close to the central Sydney urban area, EI managed the routine material characterisation, waste classification and reporting process for waste soils intended for off-site disposal to licensed waste landfill facilities.

All waste classification reporting was conducted in accordance with relevant environmental guidelines, in compliance with current waste regulations at the time of the project.

Value Added / Beneficial outcomes for Client: Assisted the Client in achieving compliance with EPA license conditions and other regulatory requirements.

waste landfield