Case Study 1


Industry: Printed Circuit Board Manufacturer

Location: South West London


Hazrem was appointed by the administrators to a printed circuit board manufacturing facility that had gone into receivership. There were concerns over ground contamination by heavy metals, and issues with hazardous substances that were left on site. These issues had to be resolved prior to the site being released back to the original landlord for redevelopment.

To understand the issues on site Hazrem initially undertook the following activities: -

Phase I + II Contaminated Land Site Investigation.
Site walkover to provide an inventory of hazardous waste.

The site walkover indicated there was in excess of 35 Tonnes of hazardous waste on site, most of which needed to be repackaged to ensure compliance with the applicable road transport and waste regulations.

The contaminated land site investigation indicated that there were various contamination hotspots mainly within the production line area of the plant. This contamination took the form of elevated levels of nickel and chrome within both the made ground and the first half metre of natural ground. The levels of contamination exceeded the soil guidance values issued by the environment agency, for both residential and commercial end use.

Remediation

After in depth discussions with the customer three approaches were adopted: -

1. Decontamination of plant / re-packaging of hazardous waste

2. High pressure water jetting to remove the visible surface contamination

3. Solidification of made / natural ground to allow redevelopment back to a commercial end use

Hazardous Waste

Hazrem Environmental safely decommissioned and removed a network of piping from the effluent dosing plant. The dosing plant contained acid, caustic, and oxidising solutions which were pumped into UN approved drums. These drums and all other identified hazardous waste items were correctly packaged, labelled and consigned to an authorised disposal facility. The pipe work was decontaminated and sent for segregation and recycling.

Surface Contamination

Utilising high pressure jetting equipment, the surface contamination was removed and the effluent directed into a temporary bund. A waste tanker was then employed to safely remove this heavy metal contaminated effluent, to an authorised liquid waste treatment facility.

Solidification

The total affected area of contamination was approximately 2000m3. Samples were taken at the initial site investigation and bench tested using Portland cement as a binder. These bench tests produced results that allowed us to proceed with the on site solidification process.

Initially the main concrete slab was removed and the made / natural ground was solidified using a hollow stem auger (allowing for the injection of the Portland cement binder), down to approximately 1.5 metres. The works lasted for approximately four weeks with verification sampling taking place at regular intervals.