The aim of this work was the study of the wastewater treatment from a leather
industry in the area of Kastoria and the optimization of chromium removal from the
effluents. A number of tanneries are located in this area, producing effluents containing
chromium. Tannery effluents are discharged to the municipal wastewater treatment
plant through the sewage treatment system, affecting the performance of the activated
sludge unit. Chemical analysis was carried out for the quantification of the
concentration and the type of chromium in samples collected from the outlet of the
tannery plant. Jar-tests experiments were conducted in the tannery effluent in order to
determine the optimum conditions of wastewater treatment for maximum chromium
removal. Aluminum sulfate and polyaluminum chloride were used as coagulants at
various dosages and the chromium removal rate was measured under various pH
conditions. It was found that the highest chromium removal was associated to a specific
coagulant, PAC-18, at a dosage of about 100 mg/L and pH 8.