Feasibility of Using Chemical Liners for Landfilling Electroplating Sludges

摘要

Seven (7) test cells, each measuring 24 m (8 ft) square and 1.8 m (6 ft) deep, were constructed in native soil at a segregated monolandfill to determine whether electroplating sludges could be stored for possible future metals recovery. Two cells each (replicates) were lined with fly ash; two with hydrous oxides of iron; two with agricultural limestone; the control was lined with native bank sand. All cells were filled with approximately the same mix of sludge (about 10,000 kg). A leachate collection and monitoring program was initiated. Natural rainfall was the only liquid added during the 30 months of field evaluation. Leachate volume, pH, EC, Cr(VI), Cr(III), Cd, Cu, Fe, Mn, Ni, Pb, and Zn were analyzed on a monthly basis. Se, cyanide, B, and Hg were examined on a less frequent basis. No significant leaching of heavy metals was observed. The excavated sludges exhibited chemical and physical characteristics similar to the raw sludges originally deposited, thus indicating that future recovery of metals is possible. A cost analysis was performed for full-scale chemical waste landfills utilizing each of the liner materials.