RECLAMATION OF SOLID-WASTE LANDFILLS BY CAPPING WITH DREDGED MATERIAL

A cost-effective method for reclaiming solid waste landfills by cappin g with clayey dredged material is illustrated in this paper using a cl osure design developed for bauxite residue landfills in Texas. The des ign consisted of capping the landfills with dredged material obtained from maintenance dredging at a nearby bay and establishing a vegetativ e layer on the cap using salt-tolerant plant species. A research metho dology comprised of laboratory cylinder tests, field revegetation test s and computer-based transport modeling was used to evaluate the effec tiveness of the various capping alternatives and to select the final d esign parameters for the landfill. Results from this study indicated t hat a cap consisting of a 0.31 m (1.0 ft) sandy dredged material layer (topsoil layer for establishing vegetation) underlain by a 0.61 m (2. 0 ft) clayey dredged material layer (low permeability layer) can be us ed as an effective barrier for closure of solid waste landfills yieldi ng effective isolation of the waste from the environment. The design d eveloped in this study can be applied to other similar solid waste sit es with minor modifications depending upon the waste properties, site characteristics, and closure requirements of the facility. (C) 1997 El sevier Science B.V.