Treatment of waste water from a winery with an advanced oxidation process (AOP)

Abstract

Producing wine entails the consumption of large quantities of fresh water, and consequently the production of large quantities of wastewater the treatability of which becomes increasingly difficult as purification standards get stringent, year after year. The problem is in the presence of aldehydes, phenolic compounds and detergents which are not easily broken down by the microorganisms of ordinary biological treatment. Wastewaters from wineries command high levels of Chemical Oxygen Demand (COD). In recent years research has focused on using Advanced Oxidation Processes (AOPs) as a means to abate the concentration of organic compounds and polluting contaminants, to render the wastewater suitable for ensuing biological treatment. The object of this study was to investigate how effective a particular type of AOP, the Fenton’s reaction, could be as a pre-treatment step aimed at destroying the toxic and biologically stable organic contaminants to reduce the organic load on the ensuing biological treatment of the wastewater. In particular, our experiments showed that if oxidation with Fenton’s reagents was followed by neutralization with lime and precipitation with bentonite, the COD reduction could be as high as 54%. Experimental tests were designed according to a 23 full factorial plan. Elaboration of results led to a model of COD reduction as a function of two significant factors. Finally, the flowsheet and the mass balance of the proposed process were defined.