This work aims to treat the liquid discharges from the olive oil crushing units to protect the receiving environments by the coagulation-flocculation process using lime and aluminum sulfate as chemical coagulants. We proceed by studying the effectiveness of the coagulation-flocculation technique in eliminating organic matter and polyphenols that characterize our samples and the possibility of reusing the treated wastewater in irrigation.

Analysis shows that adding 1.7 g/l aluminum sulfate can eliminate 58% of COD, 23% of TSS, and 24% of polyphenols, producing 21g/l of sludge, and eliminating 52% of COD, 48% of TSS, and 72% Of polyphenols requires the addition of 20 g/l of lime, but 25 g/l of sludge is produced. Combining two coagulants (1.7 g/l of aluminum sulfate and 20 g/l of lime) reduces 64 % of COD, 72 % of TSS, and 62 % of polyphenols, with the sludge is 29g/l. The germination test by cucumber seeds showed the validity of the use of treated olive oil wastewater in agricultural irrigation.