Treatment of Cork Process Wastewater by a Successive Chemical−Physical Method

Abstract

In cork processing, the operation of boiling the raw cork generates large volumes of wastewater which are more often than not released directly into the environment untreated. Even when the wastewater is treated, this is usually by retention in evaporation ponds. This procedure, however, causes bad odors and may pollute surface water and groundwater. The present study evaluates a physicochemical method involving Fenton oxidation and coagulation/flocculation for the removal of chemical oxygen demand (COD), total polyphenols (TP), and aromatic compounds (A) from cork manufacturing process wastewater. The experimental variables studied were the dosages of iron salts (from 0.001 to 0.2 mol/L) and hydrogen peroxide (between 0.06 and 1 mol/L). The integrated Fenton-coagulation/flocculation process reduced the COD of the effluent by from 22% to 85%. The removal of total polyphenols ranged from 4% to 98%, and of aromatic compounds from 2% to 97%. A further two experiments were performed modifying the manner in which the reagents were added, splitting the reagent dose (of hydrogen peroxide and ferrous salt) into two and three fractions. Finally, an economic study was made of the chemical costs deriving from the application of this purification system. The cost of a treatment with an [H2O2](o)/COD(o) ratio of 1.8 g/g (splitting the reagent dose into three fractions) that yields a COD removal of 73% was estimated to be 11.5 euros/m(3) of wastewater.

Treatment of the baker's yeast wastewater by electrocoagulation

“…EC has the potential to be the distinct economical and environmental choice for treatment of wastewater and other related water management issues. The EC process has been applied for treatment of food process wastewater such as distillery and fermentation wastewater [13,14], dairy wastewater [15], potato chips manufacturing wastewater [16], pasta and cookie processing wastewater [17], removal of nonbiodegradable organic compounds in food process industrial wastewater [18], olive mill wastewater [19][20][21], cork process wastewater [22], egg processing wastewater [23], yeast industry wastewater [8], and poultry slaughterhouse wastewater [24,25].…”

Aluminium sulfate as coagulant for highly polluted cork processing wastewater: Evaluation of settleability parameters and design of a clarifier-thickener unit

“…The operating variables used in the trials were: stirring rate (60, 150, 300 rpm), mixing time (5, 15, 30 min), pH (5)(6)(7)(8)(9)(10)(11) and coagulant dose (83, 100, 133, 166 mg L −1 of Al 3+ ). The study was performed using two wastewater types (Waters II and III).…”

“…This type of treatment -using chemical means to transform non-sedimentable particles into coagulated sedimentable particles -yields a suspension with uniform flocs that, after settling and appropriate elimination of the sludge, leaves the clearest possible supernatant. Physico-chemical processes are commonly used in water treatment [7][8][9]. Compounds such as aluminium salts are added to the effluent to destabilize the colloidal material present, and cause small particles to agglomerate into larger, settleable flocs.…”

Influence of operating parameters on treatment of egg processing effluent by electrocoagulation process

“…The drawbacks associated with the conventional and biological techniques forced the effective treatment method for complete degradation of pollutants. In recent years, electrocoagulation process has been attracting a great attention for treatments of industrial effluents such as poultry slaughterhouse (Bayramoglu et al 2006), cork process (Beltran de Heredia et al 2004), yeast industry (Kobya and Delipinar 2008), dairy industry (Tchamango et al 2010), olive mill (Un et al 2006) and distillery industry (Yavuz 2007), etc., because of the flexibility and the environmental compatibility. Electrocoagulation technique has some advantages compared to conventional methods such as easy to operate, less retention time, reduction or absence of adding chemicals, rapid sedimentation of the electro-generated flocs and less sludge production (Holt et al 2005).…”