The effect of solids on the electrochemical treatment of olive mill effluents

Abstract

A, the salinity between 1 and 4% NaCl, and experiments were performed with the effluent diluted with water to achieve the desired initial concentration. Emphasis was given to the effect of the presence of solids as well as of varying operating conditions on process performance as assessed in terms of COD, color and phenols removal. In general, degradation of phenols occurred relatively fast with conversion increasing with increasing applied current and decreasing initial organic loading and this was accompanied by low COD removal levels and moderate decolorization. The presence of solids had practically no effect on phenols removal, which, in most cases, was complete in less than about 180 min of reaction. However, oxidation in the presence of solids resulted in a substantial solid fraction being dissolved and this consequently increased sample color and the soluble COD content. The solid content typically found in olive mill effluents may partially impede its treatment by electrochemical oxidation, thus requiring more severe operating conditions and greater energy consumption.

Complexing agent and heavy metal removals from metal plating effluent by electrocoagulation with stainless steel electrodes

“…The specific energy consumption (SEC) is defined as the amount of electrical energy consumed per unit mass of pollutant (TOC and nickel in the present case) removed [31]. Table 3 summarizes the specific electrical energy consumptions obtained for EC processes run with a wide range of the applied current densities.…”

Treatment of phthalic acid esters by electrocoagulation with stainless steel electrodes using dimethyl phthalate as a model compound

“…The specific energy consumption (SEC, in kWh/kg pollutant or group parameter removed) is based on the calculation of the amount of electrical energy consumed per absolute organic carbon (COD, TOC) reduction [56]. Fig.…”

DSA electrochemical treatment of olive mill wastewater on Ti/RuO2 anode

“…Interestingly, COD appears to increase or remain unchanged during the early stages of reaction and this is more pronounced at 15 mA cm -2 . This phenomenon may be due to oxidative polymerization of certain OMW constituents like phenols and tannins, which would result in COD increase in the effluent as has also been observed by other researchers [7,13], as well as dissolution of unfiltered solids upon electrochemical oxidation, thus releasing organic matter in the liquid phase as has also been reported by Kotta et al [24]. Nonetheless, such dissolution is not expected to contribute substantially to the increased concentrations since most of the solids had already been removed from the effluent by means of filtration.…”