Decolorization and Chemical Oxygen Demand Reduction (COD) of Simulated Textile Wastewater using Fenton’s Reagent
Submitted to: Eric Siy COE 5100 – Statistical Research and Design
Chemical Engineering Department College of Engineering De La Salle University – Taft, Manila
by MARIA KATRINA A. PULUTAN MS Chemical Engineering
1st Trimester AY 2010-2011
Nature is threatened by the environmental contamination caused by the wastewater produced and discharged every day. Wastes coming from the industrial and agricultural sectors contribute a large portion. One such industry is the textile industry. About 42,000 L of wastewater is discharged daily by each of the textile industries (Maravilla, 2003 as cited by Africa, 2005). Industrial wastewater from manufacturing sources contributes a devastating effect on the body of water as well as effects on individual’s health. Production of large volumes of highly colored wastewater is one problem encountered in a textile industry. It has been estimated to generate 1 to 2 million gallons per day of wastewater (Freeman, 1995). Every textile industry is unique with respect to the type of production and the technology and chemicals used in production. Thus, it is often unusual to predict the characteristics of textile wastewater by using reported values in the literature. Other factors are the different requirements of the fibers and the different quality required for the final fabric. Amount of pollutants present in textile wastewater varies according to the wastewater management practices and amount of water used in the production. The water consumption and wastewater generation from a textile industry depends upon the processing operations used during the conversion of fibers to textile fabric. Wastewater from the textile industry is characterized with high values of Biochemical Oxygen Demand (BOD), which can cause rapid depletion of dissolved oxygen; Chemical Oxygen Demand (COD); color; and pH. The dyeing section in a textile industry contributes a high level of COD, which is toxic to biological life. This high level of COD comes from the chemicals used in the operation. The high alkalinity interferes with the biological treatment process and high color makes the water unfit for use. Due to the harmful effects of the chemicals present in wastewater, intensive researches in new advanced treatment technologies are conducted. Appropriate treatment methods for wastewaters containing toxic or non-biodegradable compounds are developed. Advanced Oxidation Processes (AOP) are often employed in the treatment of textile wastewaters. Reduction of the COD and BOD levels are often done with the use of oxidants. AOP includes chemical oxidation processes using hydrogen peroxide, ozone, combined ozone and peroxide, hypochlorite, and Fenton’s reagent; ultra-violet enhanced oxidation such as UV/ozone, UV/hydrogen peroxide, and UV/air; and wet air oxidation and catalytic wet air oxidation. Fenton’s treatment is a highly competitive method, which is being used in the wastewater industry to treat a variety of industrial wastes containing a range of toxic organic compounds such as phenols, formaldehyde, BTEX, and complex wastes derived from dyestuffs, pesticides, wood preservatives, plastic additives, and rubber chemicals. The advantages of a Fenton process, being an AOP, are process operability, unattended operation, the absence of secondary wastes, and the ability to handle fluctuating flow rates and compositions. On the other hand, it requires a higher capital and operating costs. Basically, Fenton’s reagent is a solution of hydrogen peroxide and an iron catalyst that is used to oxidize contaminants or wastewater. Fenton process has a high efficiency and can even mineralize organic compounds completely to water and carbon dioxide. In synthesis, the outstanding characteristics and principal advantages of the use of peroxide in the suitable combination with ferrous sulphate...
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