Diffuse emission and control of copper in urban surface runoff

Copper washed off from roofs and roads is considered to be a major contribution to diffuse copper pollution of urban environments. In order to guarantee sustainable protection of soils and water, the long-term strategy is to avoid or replace copper containing materials on roofs and facades. Until achievement of this goal, a special adsorber system is suggested to control the diffuse copper fluxes by. retention of copper by a mixture of granulated iron-hydroxide (GEH) and calcium carbonate. Since future stormwater runoff concepts are based on decentralised runoff infiltration into the underground, solutions are proposed which provide for copper retention in infiltration sites using GEH adsorption layers. The example of a large copper facade of which the runoff is treated in an adsorption trench reveals the first full-scale data on facade runoff and adsorber performance. During the first year of investigation average facade runoff concentrations in the range of 1-10 mg Cu/l are reduced by 96-99% in the adsorption ditch.