Sustainable Decolorization of Reactive and Acid Dye Wastewater Using Photo-fenton Oxidation Both with and Without Biodegradation: Laboratory and Field Studies

Abstract

Photo-Fenton oxidation is an advanced oxidation process (AOP) used to degrade low-concentration textile dye wastewater using expensive chemicals. The technique has shown promise in laboratory-scale projects, but has not been scaled up sustainably to function for industry. Aerobic biodegradation is a common biological treatment method used in large-scale textile industrial applications that generates large amounts of hazardous biological waste. This waste is often left open to the elements and subsequently leaches into natural waterways or onto land. This is the first study of its kind to combine the two to treat cottage-scale industry-grade textile wastewater with a dye concentration of 5 g/L and then scale up the sustainable photo-Fenton oxidation for a demonstration project in India. The need to provide rural textile communities with an effective and low-cost method to clean dye wastewater is enormous because of their lack of funds and influence in the industry; they have very little control over their environmental health and often no choice in the location of the disposal of their wastewater often dumping close to water systems. This dissertation details methods on constructing and testing a sustainable decolorization unit that includes a reactor and filter to treat 50 and 100-liter batches of textile dye wastewater for dyers in rural Bangalore, India using photo-Fenton oxidation and sand and carbon (and sometimes cotton) filtration testing whether biodegradation is also necessary as a secondary treatment. The reactor and filter is constructed of recycled rusty metal, sand, cotton fabric, and wood charcoal found locally and inexpensively. All chemicals used in the reaction are readily available in the form of sheet metal, pharmacy grade hydrogen peroxide, and household acid. Once wastewater is decontaminated it may be reused in industry or released to recharge groundwater. Test results include UV-visible spectrometry to determine color removal, COD levels to determine the removal of organics, GC/MS to quantify and qualify organics removed, ICP to quantify and qualify metal ions removal, and sludge volume production.