Book Description

This paper describes the dredging and upland disposal of about 30,000 cub. m of polychlorinated biphenyl (PCB)-contaminated (>10 ppm) dredged material for the purpose of determining a treatment method that is safe and does not induce secondary contamination. A cutterless pump dredge was used, and the dredged material was transferred to the discharge basin by pipeline. The dredging depth averaged 76 cm, as compared with the planned depth of 70 cm. No increase in turbidity was observed during dredging. The basin was subdivided, and the residual water treatment was carried out by transferring the dredged material alternatively to each basin, where dredging and plain sedimentation were conducted. The segregated water was sand filtered. About 400,000 cub. m of water was disposed, with turbidity under 10 degrees (draining standard was below 30 degrees) throughout the work. The final disposal was made by draining the disposal area, surrounding it with embankment, and covering with impervious sheeting. The dredged material was allowed to solidify, and the surface was covered with sand and gravel and sealed with asphalt.