Treatment of azo dye Acid Yellow 2G by using lab-scale vertical-flow intermittent feeding constructed wetlands

Abstract

Quite a lot of water is used in the textile industries and large amount of produced wastewater is composed during dyeing process. Treatment of textile wastewater has very important place when the role and importance of the textile industry at Turkey and around the world is considered. This aim of this study is to examine treatment performance of azo dye Acid Yellow 2G containing wastewater by lab-scale, economic designed vertical-flow intermittent feeding constructed wetlands. The lab-scaled model constructed wetlands consisted of PVC reactors, some natural and economic filling materials such as fine gravel, sand and zeolite and the natural wetland vegetation including Canna indica and Typha angustifolia. The initial dye concentration, flow rate, organic loading rate (OLR), hydraulic retention time (HRT) were 250 mg/l, 1,2 L/day, 0,075 kg/m³day, 3,75 day, respectively. The operation lasted 90 days including the planning and acclimation periods. Concentration based average removal efficiencies for control, C. indica and T. angustifolia reactors were COD; 59,56±13,15 mg/l %, 61,10±9,17 mg/l %, 64,85±8,68 mg/l % and apparent color removal for these 3 reactors were % 95,67±6,33 Pt/Co; % 89,06±4,12 Pt/Co and % 93,58±4,60 Pt/Co. The highest removal efficiencies were seen at COD and color parameters with respect to others. With regard to experiment results; zeolite layer as a bed material played a great role on organic removal. The main innovations of the experiment were, Acid Yellow 2G azo dye was firstly used at constructed wetlands and only textile dye removal was investigated without supplementary C feeds and any organic-inorganic matters. The results definetely proved that constructed wetlands is an effective and economic solution to treat colored textile wastewaters to discharge standards.