Study on optimal conditions of poly ferric chloride (PFC) dosage treating tannery wastewater

Abstract

Tannery wastewater was considered as a heavily industrial wastewater with very high amount of wastewater discharged everyday but not well-treating. The tanning wastewater from producing process contains various high strength toxic chemicals which could do the inhibition for biological treatment process leading to low quality effluent. It is required to perform the pre-treatment process by physical–chemical treatment including coagulation and flocculation in order to reduce the content of toxic chemicals before biological treatment. This study focused on investigate on the performance of Poly Ferric Chloride (PFC) as a flocculant for flocculation process in tannery wastewater treatment due to its advantages which could apply in a wide range of industries to help remove materials suspended in water. The application of PFC was conducted in batch test to find the optimum conditions including pH, PFC dose, and rotation speed in term of treating tannery wastewater performance. In addition, a common flocculant polyaluminium chloride (PAC) was chosen to compare with PFC in term of treatment efficiency and cost effective. As the result, with 0.4 ml/l PFC, pH – 10.4 with 100 rpm spins, it reaches its efficient treatment COD process to 93,3%; NH4+ 90,4% and SO42- 79,2% with could easily promote a potential alternative flocculant with excellent performance but lower cost.