INTERNATIONAL: Problem Solvers Grapple With C&D Waste

Ann Kulik

European initiatives aimed at reducing consumer packaging waste recently have received much attention. The landslides of garbage pictured in popular magazines and TV broadcasts display packaging as our foremost waste dilemma. The perception is that with enthusiastic reduction measures - prevention and all-out recycling - our disposal problems essentially would be solved.

But those responsible for waste management know that consumer products packaging makes up a relatively small portion of the waste avalanche. Packaging in Europe is estimated to account for approximately 20 percent of the household waste tonnage, which is only about 4 percent of the entire solid waste stream by weight (see figure).

Over and above the discards in people's trash cans, there are other types of waste produced in massive quantities. In the European Community, the largest fraction is agricultural waste, contributing over 50 percent to the total tonnages. Other major contributors are mining waste, power plant residue and sewage sludge. Next in line is construction and demolition (C&D) material, which makes up about 7.5 percent of all solid waste.

In West Germany, C&D waste amounts to nearly half of the solid waste remaining after agricultural wastes are subtracted. By comparison, the municipal solid waste (MSW) collected from both households and offices is less than a tenth of this total by weight.

The standard German definition of C&D waste includes three categories: debris which is largely mineral in content and results from building demolition; soil and rock from excavation activities; and solid materials of mineral content that are generated by work on streets, sidewalks and bridges.

The trend in Germany is to charge different disposal fees depending on the C&D category. This encourages sorting into reusable, hazardous and nonhazardous components. Excavation material is frequently reused but, even if not, it is suited for disposal in landfills. The same is true for demolition rubble, particularly from buildings predating 1930, which consists primarily of wood, iron and stone or brick. Because of their relatively homogeneous composition, C&D materials are increasingly sent to monofills, constructed at a lower cost than MSW landfills.

In Umdenken in der Abfallwirtschaft (Rethinking Waste Management), the authors predict that, in the future, disposal fees for nonhazardous C&D waste will lead to waste prevention and conservation of raw materials in Germany by making renovation more cost effective than demolition and new construction. Eventually, they claim, buildings will be designed for longer use and easier separation into their components once demolition becomes inevitable.

The German trade association representing the private waste industry, BDE (Bundesverband der Deutschen Entsorgungswirtschaft), judges that 90 percent of demolition material is reusable. Germany already has 220 stationary C&D debris recycling plants, and incentives are expected to boost reprocessing/reuse to almost two-thirds by the end of this decade.

The Netherlands is the acknowledged leader in C&D recycling. With more than 15 million people and a shortage of mineral deposits, this small country has compelling reasons to avoid waste. Substantial amounts of C&D waste (reported as nearly three-quarters in Public Innovation Abroad and as 65 percent in the Warmer Bulletin) are being recycled in a joint effort of the government and the road building industry. Instead of importing the road stone and landfilling the C&D waste, the Dutch recycle asphalt on site and granulate the demolition waste for use as a road base.

A Dutch plant, in Alphen aan den Rijn, processes as much as 80,000 metric tons of wood, stone, brick and reinforced concrete annually. The wood is chipped for composting, and the stones are then crushed, as well as the concrete, from which ferrous metals are magnetically removed.

Land-poor countries are not the only ones looking for ways to keep C&D waste out of landfills. In Canada, the city of Brampton, Ontario, is also on the road to C&D recycling. Roof shingles are ground and mixed with hot asphalt to create a granulated bituminous shingle material for road resurfacing. Up to 11 percent shingles, by volume, can be added to the asphalt. Anticipated benefits are a more resilient road surface, plus, if the highway test section proves successful, the opportunity to recycle up to 100,000 tons of shingles a year province-wide.