đź“Ť Location: Essex
🏢 Client: Agricultural Land Owner
🔎 Summary
An agricultural field under a standard crop rotation scheme (wheat at the time) suffered a significant diesel spill, contaminating approximately 28 by 20 metres to a depth of 1.5 metres. Following the initial excavation and soil removal, our team led the process of reinstating the field back to full use.
A key challenge in this project was the strict time constraints. The incident occurred just before the wheat was due to be harvested, meaning all remediation and reinstatement activities had to be completed by a set date to ensure the remainder of the field could be harvested at its maximum yield point. This required careful coordination and efficient execution to avoid any delays that could impact crop yield.
Additionally, the farmer needed to re-drill the field for the next crop cycle as soon as possible after harvesting. This imposed a further deadline, as the ground had to be reinstated with a high degree of accuracy to allow for immediate re-drilling and to maintain the integrity of the crop rotation schedule. The precision of our reinstatement work was therefore critical, both for the successful harvest of the existing crop and for the timely establishment of the next crop.
🎯 Objectives
Remediate diesel contamination in an agricultural field to restore safe and productive use.
Complete all remediation and reinstatement activities within a strict timeframe to ensure the remaining wheat crop could be harvested at its maximum yield point.
Reinstate the field with high precision to allow for immediate re-drilling and maintain the integrity of the crop rotation schedule.
Coordinate closely with the farmer to meet deadlines for both harvesting and re-drilling, minimizing disruption to the agricultural cycle.
Restore the field to full agricultural use as quickly and efficiently as possible, supporting both current and future crop cycles.
🛠️ Project Execution
A specialist remediation company conducted laboratory analyses of both the contaminated and reference soils. Based on these results, suitable backfill material was sourced and matched for its biodiversity and scientific properties, ensuring compatibility with the existing field conditions. A comprehensive material movement plan was developed to facilitate the delivery of this material to the site.
The backfill material was transported in eight-wheeler tipper trucks, each carrying approximately 18 tonnes. On arrival, the material was carefully graded out in 150 mm deep layers across the entire floor of the excavation. Each layer was then compacted using a mechanical roller and further consolidated by tracking in with a 14-tonne excavator. This process was repeated systematically until the reinstated ground reached a level 500 mm below the finished surface.
At this stage, both compaction and percolation tests were conducted on-site to verify the quality of the reinstatement. The compaction test, which used a pressure-based system, aimed for a result of around 5%, with all readings falling within 0.2% of the target value. The percolation test involved filling a set volume of water and timing its drainage, ensuring the rate matched that of the undisturbed field—water drained within 10 minutes, confirming the reinstated soil’s suitability.
The process of layering, compacting, and testing continued until the excavation was fully reinstated to the original ground level. All test results were sent to a laboratory for analysis to confirm compliance with the project’s specifications.
âś… Outcome & Evaluation
The reinstatement of the diesel-contaminated wheat field was a clear success, both technically and for the client’s ongoing agricultural operations. By carefully sourcing and matching backfill material to the original soil’s biodiversity and physical properties, the project team ensured that the reinstated area would not become a weak point in the field’s crop rotation system. The meticulous process of layering and compacting the soil, combined with rigorous on-site compaction and percolation testing, resulted in ground conditions that were virtually indistinguishable from the undisturbed areas.
