DO has been involved in several subdivision developments for many years. For Ravenswood Developments Ltd we provided services in land surveying, planning including consenting, site grading, civil design, geotechnical and environmental services through to construction.
During the earthworks for a later stage, peat was encountered in the underlying soil profile and required excavation for geotechnical reasons. Peat bogs are often associated with the presence of arsenic as it can bind strongly to the organic matter and becomes relatively immobile. An initial assessment of the peat indicated arsenic was present at concentrations above established background levels and would therefore render the peat unsuitable for disposal to off-site cleanfill sites. Re-use of the peat on site was not possible and alternative re-use options such as landscape yards were unable to use the peat due to the presence of large organic pieces.
DO worked with Ravenswood Developments Ltd to assess the amount and quality of peat that needed to be excavated, analyse the peat’s properties and the level of arsenic contamination, and explore options for its responsible disposal or reuse. Approximately 10,000 m3 of peat needed to be excavated for geotechnical reasons. Instead of sending this valuable soil to costly and unsustainable landfills, we assessed better ways to reuse it. DO worked with a local farm that coincidentally needed soil to improve drainage and address flooding problems. DO’s planning and civil team navigated the necessary permissions to move the soil and repurpose it there.
To make sure the reused soil met safety standards, we developed a method. This involved screening the large pieces of peat, mixing them with other unsuitable soil, and surplus topsoil from the development. The goal was to reduce arsenic levels to match or be lower than natural levels. A pilot study was conducted to ascertain the right mixing ratios and performed continuous sampling and lab analysis during the 4-month screening and mixing process.
The project faced challenges involving the removal of arsenic-containing peat from the development area. It was crucial that the source of the arsenic was identified to demonstrate to the local council that the contaminant was naturally occurring and not from anthropogenic sources. Additionally, reusing the soil on nearby land would slightly change the ground level, affecting drainage patterns. DO carefully assessed potential flooding risks to neighbouring sites and secured the necessary consents from the local council. Navigating these types of challenges is managed more seamless due to our thorough understanding of the applicable laws and working closely with regulatory bodies.
Adhering to intricate local regulations and obtaining consents can be intricate and time-consuming but DO overcame these obstacles by being well-versed in the relevant laws and maintaining close collaboration with regulatory bodies. Soil re-use requires was extensive stakeholder engagement in terms of consultation and approvals.
The soil was repurposed effectively on a nearby farm, avoiding the need for costly off-site disposal that earlier consultants had deemed necessary. This shift in approach brought about cost savings in both disposal and transportation. Through careful screening and mixing, arsenic levels in the soil were successfully lowered to match or fall below natural levels. This approach had several positive outcomes, including the environmentally friendly reuse of the soil within the same area, minimised costs linked to soil disposal, and a reduction in flooding on the reuse farm, which in turn enhanced its productivity.
DO has been involved in several subdivision developments for many years. For Ravenswood Developments Ltd we provided services in land surveying, planning including consenting, site grading, civil design, geotechnical and environmental services through to construction.
During the earthworks for a later stage, peat was encountered in the underlying soil profile and required excavation for geotechnical reasons. Peat bogs are often associated with the presence of arsenic as it can bind strongly to the organic matter and becomes relatively immobile. An initial assessment of the peat indicated arsenic was present at concentrations above established background levels and would therefore render the peat unsuitable for disposal to off-site cleanfill sites. Re-use of the peat on site was not possible and alternative re-use options such as landscape yards were unable to use the peat due to the presence of large organic pieces.
DO worked with Ravenswood Developments Ltd to assess the amount and quality of peat that needed to be excavated, analyse the peat’s properties and the level of arsenic contamination, and explore options for its responsible disposal or reuse. Approximately 10,000 m3 of peat needed to be excavated for geotechnical reasons. Instead of sending this valuable soil to costly and unsustainable landfills, we assessed better ways to reuse it. DO worked with a local farm that coincidentally needed soil to improve drainage and address flooding problems. DO’s planning and civil team navigated the necessary permissions to move the soil and repurpose it there.
To make sure the reused soil met safety standards, we developed a method. This involved screening the large pieces of peat, mixing them with other unsuitable soil, and surplus topsoil from the development. The goal was to reduce arsenic levels to match or be lower than natural levels. A pilot study was conducted to ascertain the right mixing ratios and performed continuous sampling and lab analysis during the 4-month screening and mixing process.
The project faced challenges involving the removal of arsenic-containing peat from the development area. It was crucial that the source of the arsenic was identified to demonstrate to the local council that the contaminant was naturally occurring and not from anthropogenic sources. Additionally, reusing the soil on nearby land would slightly change the ground level, affecting drainage patterns. DO carefully assessed potential flooding risks to neighbouring sites and secured the necessary consents from the local council. Navigating these types of challenges is managed more seamless due to our thorough understanding of the applicable laws and working closely with regulatory bodies.
Adhering to intricate local regulations and obtaining consents can be intricate and time-consuming but DO overcame these obstacles by being well-versed in the relevant laws and maintaining close collaboration with regulatory bodies. Soil re-use requires was extensive stakeholder engagement in terms of consultation and approvals.
The soil was repurposed effectively on a nearby farm, avoiding the need for costly off-site disposal that earlier consultants had deemed necessary. This shift in approach brought about cost savings in both disposal and transportation. Through careful screening and mixing, arsenic levels in the soil were successfully lowered to match or fall below natural levels. This approach had several positive outcomes, including the environmentally friendly reuse of the soil within the same area, minimised costs linked to soil disposal, and a reduction in flooding on the reuse farm, which in turn enhanced its productivity.
