Performance of nanofiltration and reverse osmosis for treatment of cotton dyed wastewater

The performance of low pressure Nanofiltration NF and Reverse Osmosis RO membranes for reuse of the wastewater of cotton dyeing process were studied in the present work. A simulated solution for the waste and a real solution from the factory were used in this investigation. For simulated solution after NF the removal percent for TDS and the COD were 53.3% and 33.2% at 16 bar and after RO at 25 bar they were 98.5% and 41%.For real solution, after NF the TDS and the COD removal were 25.6% and 48% at 16 bar and after RO they were97.8% and 60.0%, at 25bar. For real solution by using the NF separation the percent removal for monovalent ions were in the range of 44-77%, for the divalent ions was 77% and for the trivalent ions were in the range of 37-77%. By using RO the percent removal for monovalent ions were in the range of 86 -97 %, for the divalent ions was 99% and for trivalent ions were in the range 62-100% .The color removal percent was 100% for synthetic solution and 94% for real solution after using NF and 100% color removal was achieved for real solution by using RO.