Construction and Demolition Debris Recycling Options and Tips

Common Products and Uses of Recycled C&D Debris

• Crushed concrete and brick used in road construction, drainage
• Concrete, block, masonry and other clean debris used as borrow pit fill
• Concrete truck washout used to make onsite containing walls and bins
• Reusable building supplies such as lumber and whole bricks
• Remanufacture of wood chips into engineered woods
• Wood fuels used in co-generation plants and industrial boilers
• Horticultural mulches made from natural woody material
• Dyed, decorative mulches made from construction debris wood
• Wood chips used as bulking agent in biosolids, compost, animal bedding
• Planks and other dimensional lumber sawn from whole trees
• Corrugated cardboard containers
• Metals (steel, aluminum other non-ferrous)
• Recovered screened material (RSM) for DEP approved uses

C&D Recycling Options

Several options exist for recycling C&D waste. Waste can be separated and processed on the C&D job site itself. This requires active participation by the C&D contractor. Tight economics and the need for rapid completion of construction and demolition projects has limited this practice, although education continues in this area. Most C&D waste recycling takes place at materials recovery facilities (MRFs), where waste stream materials are processed and separated. Waste materials are separated by a combination of mechanical and manual separation. The process often involves crushing the waste in the early stages of the process to aid in the mechanical separation of the material.

Markets for wood, concrete and metal exist to accept these materials. A major factor in the success of a recycling operation is the degree of contamination of the material. Purity of the recovered product encourages higher resale prices. Product purity may be reduced at some processing facilities because of the aggressive handling of the mixed waste stream. One of the largest products of a typical C&D materials recovery facility is a recovered soil fraction (referred to in Florida as recovered screened material or RSM). This fraction accounts for 25 percent or more of the recovered waste stream at some facilities. This material may be used as clean fill in off-site operations, provided that the material is safe. The presence of hazardous chemicals in the C&D waste may limit the reuse options for RSM. Policy guidelines have been developed by DEP to approve reuse project for RSM.

Other Practices

Some C&D management practices act to divert materials from landfill disposal but are not always considered recycling. A common practice in South Florida is to use "clean" concrete as lake fill for the reclamation of borrow pits (where excavation has resulted in the creation of permanent surface water bodies). C&D waste components are also sometimes used as landfill cover. This is the most common reuse practice for screened C&D fines. Some facilities crush the entire C&D waste stream (or most of it) and use it as cover or road material in landfills.

Source: Construction and Demolition Waste Management An Overview By Timothy Townsend, PhD Department of Environmental Engineering Sciences, University of Florida