Efficient treatment for textile wastewater through sequential photo Fenton-like oxidation and adsorption processes for reuse in irrigation

Abstract

The present study investigates the treatment for textile wastewater through sequential photo Fenton-like oxidation and adsorption processes for reuse in irrigation. The optimum conditions were investigated to reach the minimum irrigation standarts in Turkey. Assessment of the treated wastewater as an irrigation water, evaluation of the agricultural waste as an adsorbent and support material for catalyst are the main significances of this study. Walnut shell and rice husk based adsorbents and catalysts which contain 10% by weight of active site BiBO3 (B:Fe,Ni) were prepared and used. At the optimum conditions of the photo Fenton-like oxidation; the highest total organic carbon removal, TOC, (20–30%) was achieved with the iron containing walnut shell based catalysts. Adsorption studies were carried out as a consequent step with walnut shell based activated carbon. At the end of adsorption step, approximately 86% TOC and 58% Chemical Oxygen Demand (COD) removals were observed. Irrigation water standards were provided for TOC, color, turbidity, total suspended solids, and pH after the adsorption step. Temkin and Dubinin–Radushkevich isotherm models were found to best fit to the adsorption data. The adsorption rate followed second order kinetic model. As a result, the treated wastewater using photo-Fenton-like oxidation and adsorption process met the quality of irrigation standarts regarding TOC, color, turbidity and TSS. Also irrigation standarts were obtained considering sodium adsorption ratio (SAR). Treated wastewater have been found to be used in cultivation of plants such as barley, cotton, sugar beet, grass, spinach, long wheat grass, date palm tree, asparagus, bermuda grass sorghum. The application of the hybrid process showed that the proposed method can be implemented effectively for the treatment of real textile wastewater.