Wastewater treatment of industrial loads with advanced oxidation in conventional systems

Abstract

In the rural regions of Latin America, wastewater treatment systems are based on conventional technologies such as the septic tanks. These treatment systems do not support biodegradability indexes lower than 0,4 measured in the form of BOD5/COD, values obtained when refractory contaminants are found in water; which in turn are associated in most cases with the intrusion of industrial wastewater. In these cases, the conventional treatment systems do not meet the regulations for which they were designed; and therefore public investment is lost to build them. This is why in the present investigation the biodegradability index of this type of ef?uents was increased, for which domestic wastewater mixed with leachate and industrial ef?uent obtained from the Chasinato creek in the Tungurahua province of Ecuador was used, in which a biodegradability index of 0,22 was obtained in BOD5/COD. An advanced oxidation process of modi?ed Fenton was applied to this ef?uent, which increased the biodegradability index and avoided reducing the pH, since in large volumes this is very expensive. The optimal concentrations of reagents were FeSO4/H2O2 = 1 and C6H8O7/H2O2 = 2; with the addition of 10 mg/L of H2O2, which increased the biodegradability index to a value of 0,46, which is a satisfactory value to be treated in conventional systems such as septic tanks; in addition to a reduction of BOD5 and COD in ef?ciencies of 12.54%; 44.4% respectively.