Cleaning (washing) operations of existing leaded paints on bridges were studied to determine the level of lead contamination in the resulting wastewater. Twelve experimental overcoating projects were let on bridges with various types of existing paint in varying states of deterioration. The projects employed different washing pressures ranging from 2500 psi to 10000 psi and various wash nozzles (fan and 0o spinner tips). KYTC standard filtration was used on 10 projects and 2 projects used an experimental filtration unit having a sand filter and two types of chemical filter media.
Prior to painting, the existing paint was analyzed for thickness, adhesion, and lead content. Wastewater generated during maintenance painting operations (potable, unfiltered and filtered) was sampled and analyzed for lead content (total and dissolved), total suspended solids and pH. No clear correlations were obtained between lead in the wastewater, wash pressures, nozzle type, or any of the existing paint parameters tested. The sand filter and chemical filter media of the experimental filtration unit provided significant removal of lead from wastewater.
Digital Object Identifier
Hopwood, Theodore II; Palle, Sudhir; and Younce, Rick, "Environmental Impacts of Bridge Cleaning Operations" (2003). Kentucky Transportation Center Research Report. 243.