Solid Waste & Recycling

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Construction & Demolition Equipment: Turnkey Decommissioning

Its plant in Nova Scotia served Sydney Steel well for many years and there are mixed emotions as people see the provider of local jobs -- and a landscape fixture for most of the twentieth century -- d...


Its plant in Nova Scotia served Sydney Steel well for many years and there are mixed emotions as people see the provider of local jobs — and a landscape fixture for most of the twentieth century — dismantled. The site is now under close scrutiny since it is located immediately next door to the highly contaminated Sydney Tar Ponds. (See “Sydney Tar Ponds Fiasco” in the October/November 2000 edition of affiliate publication Hazardous Materials Management at www.hazmatmag.com)

“While it doesn’t address the tar ponds, this decommissioning project is seen by some as a step in the right direction for the cleanup of the whole area,” says John Nicholson, an environmental engineer who grew up in the area.

In addition to the obligation to the community there is a great sense of responsibility now that a receiver controls the site and the government owns the land. The plan is to restore the property to its original state and leave former neighbours and friends with a cordial feeling.

Decommissioning

Murray Demolition of Toronto, Ontario began this “turnkey decommissioning” project in July 2001. Before mobilization a whole series of events had to happen.

A team of engineers met onsite to perform a waste minimization audit, an environmental audit and a decommissioning evaluation. With these three information resources in hand a project schedule was prepared.

In this case the waste audit identified five main streams of material that will leave the site: re-usable machinery and equipment, recyclable metals (ferrous and non-ferrous), re-usable and recyclable wood, construction and demolition waste bound for landfill (including asbestos), and rubble, concrete and brick suitable for backfill or recycling.

The goal of this project is to minimize waste and divert as much as possible from landfill. (The specific target is to send less than 10 per cent to disposal.)

The environmental audit identified three main environmental issues: polychlorinated bi-phenol (PCB) contaminated transformers, asbestos-containing material in various forms, and residual process material.

The decommissioning evaluation indicated that approximately 50 per cent of the equipment is suitable for reuse, so an investment recovery program was initiated. Approximately 44 items are in the process of being sold, including heat exchangers, processing equipment, compressors and pumps. While most projects usually only have local buyers interested in the equipment, this project has also raised interest from buyers as far as Asia and Europe. This aggressive program should reduce the cost of the project by about $1-million.

Mobilization

A four-week program was designed to initiate operation. First, asbestos abatement was performed in accordance with provincial guidelines. The abatement calls for the installation of decontamination facilities for the workers, “negative air” filtration in the work areas, and comprehensive health and safety protocols. Simultaneously the PCB handling will be carried out. Once these two main environmental issues are underway the more traditional work is planned around the environmental program.

Demolition

The demolition will be carried out using a very progressive approach. To meet the 90 per cent waste diversion target the team must be creative.

The first priority is the reusable or recyclable pieces that are not part of the investment recovery program. In addition to the main process equipment, tertiary equipment also has to be dismantled. Some of the pieces will be reused and the balance cut up and sent to a recycling facility. (This will generate approximately 900 tonnes of ferrous scrap.)

Further metal recovery will be the next step. The workers will systematically strip the buildings. While some pipe may be suitable for reuse the majority will be prepared and sent to a recycling facility.

Scrap metal has value in most projects and the benefit in this particular one is that the metals market appears to have remained consistent with the time that the tender was received. An estimated 1,100 tonnes of specialty metals will be generated, made up of copper, stainless steel and aluminum. Most of the metal will still be rebar (reinforcing the concrete) that will be removed in the next two stages.

Next steps

Next will come the structural demolition of the buildings. John Deer 450s with 70 R La Bounty sheer attachments will make quick work of the structures. Some wood material may be saved for reuse as protective hoarding at other project sites. Material separation and truck loading will continue in phases over the next 15 months.

Then comes the demolition of the concrete foundations and subsurface construction. The same heavy equipment will be used but the attachments will be different. “Breakers” and “concrete pulverizors” will be used to break up the material into “six-inch minus” pieces. The pulverized material will be utilized in final site grading. This segment will take between 30 and 45 days.

The project will be complete in about 18 months. The site offers many potential future uses, though there are no definite plans at this time.

James Sbrolla is a management consultant to the environmental industry.


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