Moldability index

The plasticity of the samples was measured fi om the Atterberg Limits (Plastic Limit, LP, and Liquid Limit, LL) and Plasticity Index (TP). The amount of added water in the mixer depends on the clay plasticity an on the consistency at which the extrusion is performed. The moisture content for stiff extrusion is 15-20 %, and 21-26 % for soft extrusions [36]. In the present work, FW, OW or OOW was added to 22 wt %, the results indicated that the plastic limit or amoimt of minimal water to mold the mixture decreased when using OW (19.7 %) or OWW (20,1 %) as mixing water. These results demonstrated that the volume of OW or OWW amount needed to produce the optimum extrusion performance is smaller than that the fresh water was used (21,9 %). This would be attributed to an additional lubricating effect performed by the addition of the wastes. Similar results were previously found in the extrusion effect when adding olive oil mill wastewater (OMW) [31, 32]. However, the plasticity index that establishes a range of moisture content in which the clay is moldable, decreased when FW is replaced by OW or OOW from 9.6 % to 6.1 % and 5.9% respectively. 

---