Coal tar-containing asphalt – resource or hazardous waste?
Artikel i vetenskaplig tidskrift, 2007
Coal tar was used in Sweden for the production of asphalt
and for the drenching of stabilization gravel until 1973. The tar
has high concentrations of polycyclic aromatic hydrocarbons
(PAH), some of which may be strongly carcinogenic. Approximately
20 million tonnes of tar-containing asphalt is present
in the public roads in Sweden. Used asphalt from rebuilding
can be classified as hazardous waste according to the Swedish
Waste Act. The cost of treating the material removed as hazardous
waste can be very high due to the large amount that
has to be treated, and the total environmental benefit is unclear.
The transport of used asphalt to landfill or combustion
will affect other environmental targets. The present project,
based on three case studies of road projects in Sweden, evaluates
the consequences of four scenarios for handling the
material: reuse, landfill, biological treatment, and incineration.
The results show that reuse of the coal tar-containing materials
in new road construction is the most favorable alternative
in terms of cost, material use, land use, energy consumption,
and air emissions.