ABSTRACT
Colour removal from effluent textile wastewater will greatly improve the quality of water bodies, which is vital to environmental health and sustainability. This study is based on finding more efficient methods of treating the effluent of textile wastewater by removing colour as a contaminant. The effects of concentration of dye solution, tie line length and weight ratio on the effectiveness of aqueous two phase system were studied. Five different textile dye colours were simulated at concentrations of 500 mg/l and 250 mg/l, and the efficiency of decolourization using polyethylene glycol/ammonium sulphate (PEG/(NH4)2SO4) and polyethylene glycol/sodium carbonate (PEG/Na2CO3), aqueous two phase systems (ATPS) as a separation technique was tested. The study showed that the best tie line length (TLL) of 52.51 % (w/w) and 55.50 % (w/w) for PEG/(NH4)2SO4 and PEG/Na2CO3 ATPS removed textile dye colours excellently within the range of 84.9 to 99.7 %. This operating condition was then used to remove colour from untreated effluent textile wastewater and result showed 99.1 % and 98.8 % of colours were removed using PEG/(NH4)2SO4 and PEG/Na2CO3 ATPS respectively. Further analysis showed an improvement in pH, total dissolve solids, dissolved oxygen, Calcium, Sulphate, chemical oxygen demand and biological oxygen demand (BOD5) of the treated water. All the parameters were found to meet National Environmental Standard and Regulations Enforcement Agency (NESREA, 2009) effluent limit discharge requirements