Some physical and engineering properties of five sewage sludges collected from different locations in Trinidad were measured in the laboratory. The properties assessed were dry bulk density, fibrosity, water content, solids content, the Atterberg limits, saturated hydraulic conductivity, density-water relations, penetration resistance, shear strength and compressibility. Air-dry bulk density of the sludges ranged from 0)37 to 0)83 Mg/m while the solids content varied from 65)4 to 90)3%. Most of the parameter values differed according to the organic matter content of the sludges. The exception to this general trend was the sludge from Trincity. The sludges exhibited very high liquid limits ranging from 165% for the Valencia sludge with the highest organic matter content of 30)9% to 66% for the Santa Cruz sludge with the lowest organic matter content of 10)8%. Proctor compaction test results showed that mean compaction for 5, 15 and 25 Proctor compaction blows varied from 0)51 Mg/m for Valencia to 1)19 Mg/m for Santa Cruz sludge. Mean penetration resistance after compaction also varied from 1)70 MPa in the Valencia sludge to 4)05 MPa for the Santa Cruz sludge. Mean shear strength varied from 59)7 kPa in Valencia to 99)7 kPa in Santa Cruz sludge. The corresponding saturated hydraulic conductivity measured on compacted sewage sludges also varied from 16)6 to 0)11 cm/h for the Valencia and Santa Cruz sludge, respectively. The compressibility of the sludges defined in terms of a compression index increased from 0)50 for the Santa Cruz sludge to 1)02 for the Valencia sludge.
Generally, the sewage sludges were found to display an engineering behaviour similar to mineral soils, differing only in the magnitudes of the measured parameters. The implications of the measured parameter values on the choice of method for use or disposal of these sewage sludges are discussed.