Making the most of waste - Dan Costello explains how to make the most of C&D waste

This report from Dan Costello formed the basis for Costello Dismantling’s award-winning entry for the Environmental & Recycling Award at the 2009 Demolition Summit in Amsterdam.

When global economic factors forced the closure of a venerable textile manufacturing company in Fall River, Massachusetts, the property was purchased to allow the site to be developed into a current, productive use.

The former textile complex was comprised of almost 75,000 m2 (800,000 ft²) of buildings dating to 1895. Current reuse is not compatible with the three-story, heavy timber framework and granite walls of the old textile mills, thereby requiring demolition of the buildings in order to recover the underlying land.

Costello Dismantling Company, Inc. was selected to perform the demolition work, which started in early January 2009. Many factors were integrated to develop the strategic plan for executing the work. An abundance of very valuable, salvageable building materials made well-planned removal and recovery techniques an essential component of the demolition plan and worker training for the project. Equipment selection was essential to have the right equipment performing the right tasks.

The square footage of the complex was fairly equally divided between 3-story 1895 era timber framed, granite walled mills, and more modern 2-story structural steel and concrete manufacturing and warehouse buildings. Two high reach excavators with rotating grapples led the timber building dismantlement, while a fleet of five excavators with shears and grapples dismantled and processed the steel buildings into finished mill-ready grades of structural scrap, and bundle grades processed by a portable baler.

Having the luxury of space created by utilizing the clean slabs on grade of the recently dismantled buildings, prepared grades of scrap were processed and stockpiled to await the proper shipping time based upon closely monitored export and domestic scrap market demand. In the current economic environment, markets for scrap commodities are driven by very specific demands. When that demand is met, prices drop quickly. It is important to pay close attention to economic forecasts and consumer information, and above all, to have prepared grades of material ready to be able to fill an order when demand spikes. During this project, over 1,800 tonnes (2,000 tons) of prepared scrap was sold. Market fluctuations of over US$70 per ton occurred during the project. By paying close attention to the market, scrap was sold at four order points that were at or close to peaks.

Preparation of the timber mill buildings prior to dismantlement is the secret to being able to recover large volumes of high quality wood. This mill complex was constructed of southern yellow pine timber framing and structural sub flooring. Southern yellow pine, also known as heart pine, antique pine or long leaf pine, is extremely popular around the world. The large timbers and floor decking boards are resawn to create beautiful flooring, cabinetry and millwork, as well as exposed structural members for new construction.

While being extremely strong and durable (which is why yellow pine was chosen for mill applications at the end of the nineteenth and early twentieth centuries), it can be very fragile if not handled properly during the dismantling process. Rough handling can break or shatter timbers, which quickly changes them from a valuable resource to just more wood debris that carries a fee for disposal.

Costello has had experience dismantling dozens of similar vintage mill buildings. High reach excavators with rotating grapples provide the greatest precision and control to extract each individual piece of wood and cause the least physical damage to the product. Once removed from the demolition zone, the wood was brought to a separate processing area for grading, de-nailing and packaging to economic shipping quantities. With well over one million board feet of lumber to deal with, the marketing effort was continuous. In the end, buyers from 10 states and several foreign countries purchased wood that was loaded onto trailers or sea-land containers right at the job site.

Unlike most late nineteenth century mill complexes that were made of brick, the Fall River mill buildings were constructed of 0.9 m (3 ft) thick granite walls. The "Fall River Pink" granite was quarried locally, perhaps even on-site in the area of a large millpond. The buildings would yield 50,000 tons of granite that had to be handled as part of the demolition process. It became apparent very quickly that the stone had a great value for architectural, landscaping and masonry applications. A vibratory deck screen with 12" grizzly and a triple deck screening plant were used to mechanically sort and classify stone to grades of highest to lowest value.

Residual stone from the screening process was integrated with concrete and brick to be crushed onsite to create a specified product that will meet the future filling and grading requirements for the new site development. The larger, positive environmental impact of creating a useful product from the demolition waste stream is significant. The site owner responded positively to the suggestion to create material for beneficial use onsite; thereby avoiding huge volumes of truck traffic hauling material through the surrounding community leaving the site, and a similar number of trucks bringing fill through that same community back to the site.

One of the biggest successes and learning opportunities was the manner in which C&D debris was handled to promote increased recycling rates by producing specified feed stock grades to a local bio mass fuel processing plant. Early in the project, Costello invited the facility managers from the fuel processing plant to the job site to understand the dismantling and material handling aspects of a demolition project. They provided guidelines and specifications for allowable and excluded materials from the wood waste stream and sizing requirements for their plant. The entire Costello project team then visited the fuel plant to see and understand their process equipment capabilities and end product. The interchange of ideas allowed Costello to produce a high quality feed stock very beneficial to the fuel plant. The result was a win-win for both sides, and the template for enhanced recycling in every project Costello has been a part of since.

The entire project crew worked continually to improve salvageable recovery, recycling rates and recycling quality. The project yielded 100,000 tons of stone, concrete, brick, metal and wood which were reused or recycled. Less than 2,000 tons of non-recyclable roofing materials, insulation and non-metallic building materials were sent for disposal. A recycling and reuse rate of over 98% was achieved on this project. There was not a single "lost work" incident, and the project was completed on schedule.

The Fall River textile mill had been a major centre of industry for over one hundred years. The property will be revitalised as a new commerce centre, while components of the old mill will continue to live on in the local area and around the world in a new revitalised form through the demolition and recycling process.