Recycling means collecting waste and reprocessing it into raw materials for new products. Recycling not only saves landfill space and helps prevent the pollution associated with landfills, it saves money by avoiding rapidly'-rising disposal fees.
Many Minnesota builders already recycle some construction waste. Here is a list and some examples of reuse and recycling options currently practiced.
1. Sorting recyclable materials from other wastes on-site during the construction process. Establishing separate containers or areas for recyclable materials is familiar to many Minnesotans accustomed to sorting household wastes for recycling. Currently, many Minnesota contractors do some on-site waste sorting to keep paper, cardboard, and garbage out of waste loads considered "clean demolition fill" (inert materials accepted at demolition landfills). The tipping fees charged by demolition landfills are significantly lower than the fees charged by sanitary landfills because demolition landfills accept only such materials as wood, concrete, and roofing materials, which pose less environmental risk and require fewer environmental safeguards. Although sorting "clean demo" waste from other waste is not recycling, it shows that on-site separation of waste types is possible.
For some sorted recyclable materials, haulers will remove filled containers at no charge. For example, when Opus Corporation built the University of St. Thomas' downtown Minneapolis campus, a local scrap yard placed a 12-cy container on site during construction of the building's foundation and steel frame. Workers put waste metals such as re-bar, metal stud off-cuts, and scrap angle iron into the container. The scrap yard received revenue for the metals and Opus saved money on hauling and disposal charges. Many scrap yards -offer this service for a fee that is offset by the value of the materials collected," thus providing a net gain for the builder.
Another example comes from Pete Schwab, who has had success sorting cardboard, metals, and sometimes repairable pallets into separate piles or containers on building sites. According to Schwab, a Winona company removes the sorted recyclables from thé sites at no charge.
As noted in the introduction to this guidebook, however, many contractors who have tried on-site sorting of recyclable materials have had mixed results. Training a variety of subcontractors to sort waste types into separate containers can be difficult. Andy Aagard of Aagard Environmental Services in Minneapolis noted that, despite having a separate container for corrugated cardboard available during one large construction project, every load of cardboard was rejected at the market due to contamination.
Aagard also noted |hat, if there is not enough material to fill most of a container, the avoided disposal cost and revenue from the material may not be enough to offset the hauling charge. The Recycling Economics section of this guidebook provides a detailed worksheet with some examples showing how to determine when on-site sorting of recyclable rfiaterials is cost-effective..
One example of innovative on-site sorting of recyclable materials comes from Central Roofing Company of Minneapolis. According to Cathy Smith, the high disposal cost from one re-roofing job prompted ,the company to think about reuse and recycling alternatives, which resulted in the reuse or recycling of about fourteen 30-cy boxes worth of material — altogether about 420 cy. In this case, polystyrene sheet insulation and perlite insulation found under a layer of PVC roofing material and gravel had remained quite clean and dry. The roofing team decided to package, store, and reuse the two types of insulation on future roofing projects. On its first attempt, the team salvaged about a third of the insulation material, but the labor needed to package and store it was too expensive.
However, the remaining polystyrene sheet insulation was recycled through Styrotech, a local polystyrene manufacturer. Sorting materials from this re-roofing job was fairly simple. First the roofers removed the roof gravel, which wasdonated for the bujlding's parking lot construction project. Although roof gravel is not always suitable for this purpose, this particular gravel could be used as a class five base material.
The underlying layer of polystyrene insulation was tossed from the roof directly into a waiting truck.
Central Roofing is currently trying to identify other, more cost-effective ways to re-use clean materials from PVC and rubber-type re-roofing jobs, since many roofs of this type in the Twin Cities area are beginning to need replacement. Central Roofing plans to try reusing rubber roof sheets from their next re-roofing job for tarps.
Despite these problems, some contractors have found it feasible to sort certain materials on site for recycling. Examples of such materials are metals (as noted above), concrete and block (crushed for road bed material), cardboard, and dimensional lumber. Also, subcontractors (e.g., electricians and plumbers) usually recycle valuable metal scraps such as copper tubing.
The Schwab Company makes sure recyclables are sorted cleanly by giving subcontractors a choice: either they dispose of their waste materials in the proper containers or assume responsibility for disposal of their waste. Some subcontractors choose the latter option, but many prefer having Schwab
Company deal with disposal. Also, many subcontractors generate a fairly homogenous waste, which makes sorting easy. For example, the primary waste stream for electrical contractors is often the cardboard containers used to hold . electrical supplies.
2. Sorting by materials recovery facilities and transfer stations. One of the easiest ways for builders to recycle is by contracting with a waste hauler who delivers wastes to a materials recovery facility (MRF) or transfer station where recyclable construction wastes are sorted for markets and the remaining wastes consolidated for disposal. The Recycling Markets Directory in this guidebook lists haulers, MRFs, and transfer stations that sort at least three recyclable materials from mixed construction waste.
One example is Materials Recovery Limited (MRL) in Rosemount, where construction waste loads are sorted into the following recyclable components: cardboard, concrete, metals, dimensional lumber, and pallet wood. MRL hauls wastes mostly from residential construction and remodeling sites. Nails are mechanically removed from wood, which is then chipped into turkey bedding.
Some separation of recyclables occurs at landfills. For example, the SKB Rich Valley Demolition Landfill in Inver Grove Heights routinely monitors incoming loads and pulls out recyclable materials such as scrap metal, wood (for mulch), and household appliances.
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