A continuous dehydration-solidification treatment system is proposed for the geotechnical utilization of the waste sludge discharged from construction works. As the dehydration level can be expressed in relation to w/w, (the water content of the sludge normalized by the liquid limit), regardless of the other properties in the sludge, the solidified properties of the sludge stabilized by cement after dehydration are assessed and normalized by the index of w/w,. The solidified strength can also be estimated from w/w,. According to these experimental results, an efficient treatment level is calculated using two indexes, Q(r) (the ability of the dehydration treatment versus time) and S-r (the ability of the dehydration treatment to use fully a solidification plant with a 1 m(3)/h ability). The effects of the sludge properties on the efficient treatment level are presented to indicate a concept for constructing the dehydration-solidification treatment system. In conclusion, the application of the sludge as an earthen materials is reviewed in relation to the treatment Level.