Oil leak at local school

After a period of unexplained heavy use of oil, a school got in touch to ask us to help them.

A heating engineer was appointed to carry out a pressure test. This confirmed there was a defect within the line, resulting in a considerable volume of oil being lost into the ground at the rear of the school buildings.

Following this, we were asked to undertake investigations and to identify and evaluate the risks associated with the above scenario.

The investigation phase of works consisted of a CCTV survey of the various underground services present across the site and extensive soil/perched water/surface water sampling to determine the areas impacted by the oil loss.

We identified a large area of kerosene-contaminated ground, which posed a risk to school buildings and its occupants, the on-site sewage treatment system, on-site water supplies, and neighbouring third-party lands.

Our experienced technical team devised a comprehensive remedial programme of works to reduce the risks associated with the oil loss on site. Integral to this was to ensure the safety of the school children and staff.

Frequent communication with the school Principal was of fundamental importance, so that sections of the school yard could be segregated at certain times to allow for the use of plant and equipment. In order to minimise the inconvenience to the school, we ensured that the commencement of the remedial programme coincided with school summer holiday period.

The remedial works completed on site consisted of the following:

• Excavation of contaminated soils in the vicinity of the point of oil loss
• Thorough clean-out of the contents of the package treatment plant and tertiary treatment system, to remove free phase kerosene and contaminated liquid/solid materials
• Excavation of contaminated soils adjacent to the tertiary treatment system
• Installation of groundwater monitoring wells within the rear school yard, to determine the level of risk to the on-site potable water supply well
• Implementation of a water quality monitoring programme, to assess for the presence of contaminants within the stream, groundwater monitoring wells, potable water supply to the school and separate water supply to the school toilets via the rainwater harvesting tank
• All disturbed areas were reinstated to a high standard

Our in-depth investigation, careful planning, and skilled remediation works ensured that all identified risks were appropriately dealt with. This meant the school could be safely used again for all the children and staff.

The required works were carried out in a timely manner, to minimise the level of disturbance within the rear school yard.