Schwager J.,Cerema Direction Territoriale Est Laboratoire Regional Of Nancy |
Schaal L.,Cerema Direction Territoriale Est Laboratoire Regional Of Nancy |
Simonnot M.-O.,CNRS Reactions and Process Engineering Laboratory |
Claverie R.,Cerema Direction Territoriale Est Laboratoire Regional Of Nancy |
And 2 more authors.
Journal of Soils and Sediments | Year: 2015
Purpose: The increasing surface area of green roofs (GR) may have a significant impact on the quantity and quality of urban drainage. However, the chemical quality of effluents produced by GR in comparison to atmospheric deposit and other roof surfaces has to date been poorly assessed. It is necessary to determine whether a green roof acts as a sink or source of pollutants. This work was conducted to study the capacity of four materials commonly used to build green roofs. Materials and methods: Leaching tests experiments were performed on three substrates and one drainage material. Sorption kinetics and isotherms were also established for Cu and Zn thanks to batch experiments. Results and discussion: Results showed the variability of release according to the material and pollutant considered. The equilibrium time for adsorption was high (5 h to 3 days) for all materials. Expanded clay was identified as the material with the highest ability to retain Zn and Cu; also, desorption was limited with this drainage material. In the substrates, Cu was mainly sorbed by organic materials, which induce an important desorption rate due to organic matter leachability. Conclusions: In conclusion, the study showed that the effect of green roofs on water quality is strongly dependent on the materials used. That is why a characterization of the leaching and sorption capacities of materials should be carried out prior to green roof construction in a context of storm water quality management. © 2014, Springer-Verlag Berlin Heidelberg. Source