Environmental Science & Engineering - November 2005

Dump trailer liners used in decommissioned foundry clean-up project

By Glenn Stokes

Deployment of the form fitted liner is a one or two person job.
A solution was required for an asbestos contaminated soil clean-up and transportation project in Sarnia, Ontario, to make way for a cloverleaf (on and off ramps) for Highway 402 which was scheduled to be constructed through the former Holmes Foundry site.

The task was to come up with a containment system for the contaminants found on site to prevent them from becoming airborne during transportation to the landfill. The system also had to offer a barrier, as the soil was wetted prior to excavation in order to minimize dust. Therefore, water runoff was a concern plus any rain that the liner might be exposed to up until the point where it was backfilled and capped. The lining system would also remain in the landfill so it was important that the liner had enough structural integrity that it would remain intact as it was deployed off of the back of the dump trailer.

Holmes Foundry had been in existence for some 80 years up until 1988. During that time it saw several different types of businesses including a foundry and two different insulation plants. At some point during the history of this site it became contaminated, amongst others, with silica quartz and asbestos. The concern today is that by disrupting the soil there is a possibility of allowing the asbestos to become airborne, causing a possible health risk.

In order for Dallas Haul Inc. to comply with the Ontario Ministry of the Environment regulations in transporting asbestos from this site to a local landfill, Dallas was required to utilize a lining system that was capable of attaining compliance for a Certificate of Approval. The lining solution came from HQN Industrial Fabrics, coincidentally, also located in Sarnia, Ontario. The liner chosen was a 6 mil reinforced polyethylene material with a drawstring seamed into the top hem. The liners supplied were 38 feet long x 96 inches wide x 144 inches high. This size configuration fits the box perfectly at the bottom with the liner pushed into the corners so that splits in the seam do not occur during loading of the contaminated soil into the box. The side walls are constructed much higher than the box so that there is space for the liner to fold over the top of the box and be securely fastened, with bungee cords, which keeps the liner in place during high winds.

The lining material itself is quite impermeable, particularly with all seams being double folded and stitched. It is also a particularly strong yet inexpensive liner which is ideal for a one-time usage product. During deployment, the liner allows the entire load to come away from the trailer even during the winter months in a frozen state. Liners reduce wash-out costs, freezing, leaking, dust problems and are quite effective at keeping odors from penetrating into the steel. This can be a major problem as odor can effectively contaminate a box beyond usage for other applications. Therefore, liners and caps extend container life while reducing maintenance costs.

Using the liner’s integrated drawstring to encapsulate the contaminated waste.

So far during this clean-up, Dallas Haul has used over 300 liners, with further excavation still to come. By using a fleet of trucks, Dallas is able to have one truck filled while the next truck in the queue prepares the liner (one person job, takes 15 – 20 minutes). Intimate contact with the contaminated wetted soil was the responsibility of one person, in full safety gear, including a full respirator. This person was charged with the job of cinching up and tying off the drawstring, thereby encapsulating the waste. The potential contaminants were further protected from the environment by washing off the truck tires prior to leaving the job site and a cover was pulled back over the top of the truck. In the event of inclement weather, HQN was on standby with custom manufactured raincaps and mesh covers.

As there are a wide variety of contaminants and hazardous wastes along with various sizes of roll off boxes, rail cars, luggers, dumpsters and dump trailer sizes, there are many liner and raincap materials and sizes to choose from which makes this system quite versatile.

Glenn Stokes is with HQN Industrial Fabrics.
Contact: gstokes@hqnfabrics.com

See our home page on how to order your subscription. We regret we can only accept orders from Canada.