Combination technology of ceramic microfiltration and reverse osmosis for tannery wastewater recovery

Treatment of highly contaminated composite tannery wastewater from common effluent treatment plant (CETP) was undertaken using indigenously developed ceramic microfiltration membranes. The effluent had a high load of organic and inorganic materials represented by about 5680 mg/L of chemical oxygen demand (COD), 759 mg/L of biochemical oxygen demand (BOD5) etc. The current study proposed a dual stage treatment involving microfiltration (MF) followed by reverse osmosis (RO) compared to conventional process. The final water was fit for reuse in the tanning process. Organic loadings in terms of COD and BOD5 values were below detection limit and turbidity was reduced to 0.025 NTU in the combined process. Reuse study was conducted using cow hide and leather properties were compared to that of control. Leather tanned with RO permeate had better tensile strength, stitch tear strength and grain crackness properties. Dye uptake was also more in case of leather tanned with RO permeate.