|
Ground Science provides a comprehensive range of environmental services for projects of any size with the aim of delivering professional, prompt and thorough consultancy at a cost effective price. To make an informed decision about managing the environmental risks associated with your project, Ground Science has the experience and the capabilities to assist you every step along the way.
Our key services include (click for more details):
|
|
ENVIRONMENTAL SITE ASSESSMENTS
Site contamination is an issue which may impact on the land owner, tenant, potential land purchasers, surrounding land uses and future land uses. Site contamination can be considered as any pollution of land from both past and present uses, resulting in concentrations above background levels and where concentrations are such that they pose significant environmental and/or human health problems.
An environmental site assessment is a detailed investigation of a site which is designed to determine whether there has been any potentially contaminating land uses at the site, probable contaminates and the location of any contamination.
The first stage of the assessment process is a preliminary site assessment, which generally consists of a detailed historical review, a site inspection and in some circumstances, limited sampling. The preliminary assessment determines whether the site has any potential for soil or groundwater contamination. If so, a detailed site assessment may be required.
The detailed site assessment builds on the preliminary assessment and may involve a comprehensive sampling program to confirm the extent, nature and concentrations of the contamination as well as establishing the lateral and vertical distribution of the contamination. A detailed report will provide an assessment on the land based on the laboratory results and the sites history.
Ground Science can assist you with all facets of environmental assessments and conducts all works in accordance with Australian Standards, National Environmental Protection Measure guidelines, and EPA guidelines. The level of assessment can be modified to meet your specific needs.
|
|
PROPERTY DUE DILIGENCE
In an age of increasing liability and tighter environmental regulation, environmental due diligence on all types of property, particularly industrial, is now essential. The provisions of the Victorian Environment Protection Act 1970 tend to have the effect that the occupier will generally bear liability for contamination. So when land ownership changes occur, the environmental liabilities transfer to the new owner.
Prior to the acquisition of any property, as part of your due diligence, an environmental assessment should be considered as it may save you in the long run.
If you are selling a property, in order to maximize your return from the sale, an environmental assessment will minimize the environmental and financial risks a purchaser is asked to accept in the contract of sale.
If you have a tight time frame, Ground Science can talk you through your options and develop an assessment approach which will allow you to make an informed decision.
|
|
|
CHILDREN’S SERVICES SOIL ASSESSMENTS – CHILDCARE & SCHOOLS
The Department of Education and Early Childhood requires an assessment of soil at all sites proposed for use as a children’s service, and in some cases, sites which are already in use as children’s services. Soil assessment is part of the process of considering whether the proposed location of the children’s service is considered suitable under section 10 of the Children’s Services Act 1996.
Soil assessment may be required when children will have or currently have access to the soils at that service. As a minimal, a preliminary investigation is required for existing licensed children’s services, when meeting the following criteria:
- Earthworks or excavations exceeding 1m in depth
- Alterations to the existing buildings or extensions of the land boundaries
- The alteration or extension will be used for the children’s outdoor play area
- No soil assessment has been undertaken previously
Ground Science has undertaken many children service soil assessments all over Victoria and can guide you through the complete soil assessment process.
|
| |
CONTAMINATED SOIL TESTING FOR OFF-SITE DISPOSAL
Prior to the off-site disposal of soils, it is a requirement of the EPA – Victoria that the soils be classified as either:
- Fill Material
- Category C – Contaminated Soil (low level)
- Category B – Contaminated Soil
- Category A – Contaminated Soil (high level)
Soils which are categorised into either Category C or Category B contaminated soil will require disposal as Prescribed Waste to an appropriately licensed landfill using an EPA Transport certificate system, unless an exemption is issued. Soils which are categorized as Category A contaminated soil will require treatment to reduce or control the hazard before meeting acceptance criteria for disposal at an appropriate EPA licensed landfill.
Ground Science has an in-depth knowledge of the requirements for sampling and classifying for off-site disposal of soils. Ground Science has continually implemented sampling and analysis strategies which have successfully and justifiably reduced the category of soil classification, saving the client thousands of dollars in disposal fees.
|
|
UNDERGROUND TANK REMOVAL AND VALIDATION
Underground Storage Tanks (UST’s) can lead to contamination of soil and groundwater in the vicinity of the UST due to corrosion, cracking or rupturing. Failure to comply EPA guidelines can result in fines and extreme clean up costs.
To help prevent contamination of existing, Ground Science can assist with UST management plans and groundwater installation and monitoring for existing or proposed UST’s.
|
| |
SEPTIC TANK LAND CAPABILITY ASSESSMENTS
A Land Capability Assessment (LCA) is a detailed report that identifies essential environmental features associated with the site for sustainable on-site wastewater management. The objective is to develop a management regime, minimize environmental impacts and enhance long-term sustainability. In unsewered areas, an LCA must be undertaken for a site that requires the installation of a wastewater treatment system.
Ground Science can assist you with the preparation of LCA which involves a thorough site inspection, soil sampling and analysis, and a comprehensive report that will outline which on-site wastewater treatment system is most suited to your site. The size and location of the land application area will be determined using water balance modeling specific to your site, which will minimize environmental and human health impacts.
Ground Science has built relationships with Councils across Victoria and has tailored assessments to meet the specific requirements of each Council area.
|
|
The setback distances listed below are an extract from the EPA Code of Practice and are minimum distance required for the separation buffer between the wastewater disposal field and other specific site sensitive features.
| Situation |
Setback (meters) |
Building |
|
Wastewater field upslope of building |
|
Wastewater field down slope of building |
|
Allotment boundary |
|
Wastewater field upslope of adjacent lot |
|
Wastewater field down slope of adjacent lot |
|
Services |
|
Water supply pipe |
|
Potable supply channel (wastewater field upslope) |
|
Potable supply channel (wastewater down slope) |
|
Gas |
|
Underground water tank |
|
Stormwater drain |
|
Swimming pool |
|
Cutting/escarpment |
|
Surface waters (upslope from) |
|
Dam or reservoir (potable, including food production)* |
|
Dam or reservoir (stock & non potable) |
|
Stream or channel (continuous or ephemeral, non potable) |
|
Stream (potable water supply catchment) |
|
*does not apply to dams and reservoirs above ground level |
|
Groundwater & bore |
|
Potable or non potable |
|
|
AS1547:2000 outlines factors affecting the construction and operation of common land-application systems and a guide to selecting a system to suit the identified site and soil constraints. A range of possible land application systems will be considered on a case by case basis, which include: |
|
TRENCHES & BED SYSTEMS |
A conventional bed system comprises of 20–40mm distribution aggregate to fill the base of the bed to a maximum depth of 600mm. Perforated pipes or arches are placed within the gravel aggregate, approximately 75mm from the top of the aggregate. Fine gravel (5 – 10mm) or geo-textile sheeting is used to line the coarser underlying gravel. This will prevent finer particles moving into the larger spaces in the gravel. A minimum of 150mm topsoil overlays the geo-textile sheeting to provide a growing medium and aid in the evapotranspiration process. A convex surface encourages the shedding of a proportion of rainfall.
A distribution box provides a mechanism for evenly dosing each of the pipes. The pipe system needs to distribute the effluent evenly over the whole area. The lateral spacing of the pipes should not exceed 2.0m.
The absorption bed needs to be positioned so that the effluent from the septic tank can be gravity fed if possible, otherwise a pump system must be incorporated. The floor of the bed is to be level in all directions and where a slope of more than 5% is present, it may be necessary to step several narrow beds, each parallel to the contour down the slope.
A filter is installed in the main line to remove fine particulates that could block the emitters. This must be cleaned regularly following manufacturer’s instructions. Vacuum breakers should be installed at the high points in the system to prevent air and soil being sucked back into the drippers when the pump shuts off. Flushing valves are an important component and allow periodic flushing of the lines, which should be done at least yearly. Flush water can be either returned to the treatment system, or should be released where it will be readily absorbed.
All trenching must be backfilled properly to prevent preferential subsurface flows along trench lines, particularly where trenches are not absolutely parallel to contours. Irrigation areas should not be subject to high traffic movement, especially by vehicles, otherwise compaction around lines can lead to premature system failure. |
|
| ETA SYSTEMS |
The ETA system comprises of 20mm hard clean gravel to fill the base of the bed to a depth of 150mm. The volume of the gravel, in cubic meters is 0.15 x area of ETA bed. Fine gravel (5–10mm) or geo-textile sheeting is used to line the coarser underlying gravel. This will prevent sand moving into the larger spaces in the gravel. 300mm of fine sand (0.1mm) is desirable to overlay the geo-textile sheeting as it provides a large void ratio and a high capillarity. The volume of the sand required, in cubic meters is 0.35 x area of ETA bed. Membranes lining the ETA bed should be at least 0.2mm thick and the joins overlapped and sealed with high quality waterproof tape to ensure water tightness over many years. 100 mm of quality loam topsoil is placed as the top layer to provide a growing medium and aid in the evapotranspiration process. A convex surface encourages the shedding of a proportion of rainfall.
A distribution box provides a mechanism for evenly dosing each of the pipes that are installed at the base of the bed, in the coarse gravel layer. The pipe system at the base of the bed needs to distribute the effluent evenly over the whole area. Pipe diameters of at least 90mm slotted PVC pipe are firstly laid on 50mm depth of gravel filled to a total depth of 150mm. The lateral spacing of the pipes should not exceed 2.0m.
The ETA bed needs to be positioned so that the effluent from the septic tank can be gravity fed if possible, otherwise a pump system must be incorporated. A pump will be required for this system as the proposed LAA is positioned upslope. The floor of the bed is to be level in all directions and where a slope of more than 5% is present, it may be necessary to step several narrow beds, each parallel to the contour down the slope. |
|
| IRRIGATION SYSTEMS |
The subsurface irrigation comprises a network of drip-irrigation lines that are specially designed for use with wastewater. The pipe contains pressure compensating emitters that employ a biocide to prevent build-up of slimes and inhibit root penetration. The laterals are usually 0.6 to 1.0 m apart, roughly parallel and along the contour if possible. Installation depth is commonly 100-150 mm. It is critical that the irrigation pump be sized properly to ensure adequate pressure and delivery rate to the irrigation network.
A filter is installed in the main line to remove fine particulates that could block the emitters. This must be cleaned regularly following manufacturer’s instructions. Vacuum breakers should be installed at the high point/s in the system to prevent air and soil being sucked back into the drippers when the pump shuts off. Flushing valves are an important component and allow periodic flushing of the lines, which should be done at least yearly. Flush water can be either returned to the treatment system, or should be released where it will be readily absorbed.
All trenching used to install the pipes must be backfilled properly to prevent preferential subsurface flows along trench lines, particularly where trenches are not absolutely parallel to contours. Irrigation areas should not be subject to high traffic movement, especially by vehicles, otherwise compaction around emitters can lead to premature system failure. |
|
MOUND SYSTEMS |
A mound system is a drain-field that is raised above the natural soil surface. The mound is composed of a sand fill that has a gravel-filled bed and a network of small diameter pipes. From the pump chamber, effluent is pumped through the pipes in controlled, low pressure doses so that uniform distribution is achieved throughout the bed. The wastewater comes out of the pipes through small holes and trickles downward through the gravel bed and into the sand. Treatment occurs as the wastewater moves through the sand and returns to the natural soil. Mounds have the benefits of increasing separation distance between the point of application and the soil and groundwater, they facilitate nitrogen reduction and they permit increased evaporation and transpiration. |
|
| FIELD SOIL PERCOLATION |
| Testing using the Talsma Method AS/NZS 1547:2000 is another method used in the agricultural and septic tank assessment field. Ground Science is pleased to travel state wide to perform this field based test. |
|
|
