Water is an essential element in the food industry. The resulting wastewater is often returned to the natural environment without treatment; this can be a major source of pollution to the environment. Among these food processing industries, there are slaughterhouses that are classified as dangerous, unhealthy and uncomfortable so treatment of their discharges is required prior to discharge. This work is primarily to recommend a suitable physical-chemical treatment flocculation by coagulation using ferric chloride (FeCl3) as a chemical coagulant. The Jar-test tests were used to find the optimal conditions that reduce suspended solids. The results obtained after decantation show a degree of removal of suspended solids of about 98%. The resulting experimental equation for the correlation between the time of settling and the height of the sedimentation column was validated according to the law of Kynch.