摘要：The wastewater of leather industry which is one of the most widespread industries having large amount of water consumption and very high pollution loads, may be characterized by several key parameters including toxic pollutants exhibiting toxicity. Therefore the effluent of leather tanning industry must be handled carefully during both treatment plant design and operation. The aim of this study was to improve the coagulation process for toxicity reduction of raw wastewater taken from a leather tanning district central treatment plant (Solofra, (Avellino, Southern Italy). A series of jar test experiments on three samples taken between February and July 2005, were performed using ferric chloride, ferrous chloride, aluminium sulphate and polyaluminium ferric chloride (PAFC). The optimum coagulation conditions for the first sample were determined as 8.5 pH and 900 mg l-1 dose of PAFC with the addition of Ca(OH)2 which resulted in a 76% COD and 98% TSS removal and more than 50% of D. magna immobilization (at 50% dilution) reduction. Coagulation experiments performed on second and third samples showed that PAFC resulted in the highest COD removal among the coagulants tested The results that PAFC, recently developed coagulant, is the most promising one for leather tanning wastewater, thus, improved coagulation followed by biological treatment can result in safe effluent to aquatic environment.
