Treatment of Highly Polluted Hazardous Industrial Wastewaters by Combined Coagulation–Adsorption and High-Temperature Fenton Oxidation

Abstract

A coupled coagulation−adsorption and high-temperature Fenton oxidation treatment has been applied for the treatment of three different industrial wastewaters bearing high concentrations of hazardous pollutants. High percentages of chemical oxygen demand (COD) removal (>85% for the pesticide and security inks effluents and 65% for the cosmetics ones) were achieved in a first step using FeCl 3 as coagulant and bentonite as adsorbent. This reduced dramatically the amount of H 2 O 2 required in the further high-temperature (120 °C) Fenton oxidation (HTF). Using the stoichiometric amount relative to COD around 70% of the remaining organic load was mineralized. The combined treatment allowed achieving the regional discharge limits of COD and ecotoxicity at a cost substantially lower than the solution used so far where the three wastewaters are managed as hazardous wastes. Working at high temperature would not represent an important drawback since around 90% of heat can be recovered from the treated off-stream.

Preparation of magnetite-based catalysts and their application in heterogeneous Fenton oxidation – A review

“…The Fenton process has been successfully applied to the treatment of highly polluted wastewaters such as cosmetics [4,19], olive-mill [20,21], chemicals [4], pulp and paper [11], power plants [5] or sawmills [6], among others [22].…”

“…The costs associated to its treatment and disposal can represent up to 10-50% of the total operating cost of the wastewater treatment [4,8]. Thus, reducing the amount of sludge is imperative and has stressed the importance of using iron-bearing solid catalysts in the process in order to avoid the continuous loss of catalyst associated to the homogeneous Fenton process.…”

“…In-situ production of H 2 O 2 and oxidation using magnetic catalysts H 2 O 2 consumption represents, by far, the main operating cost in Fenton-based processes [4,27,97] and thus, any reduction is beneficial for the economy of the system. In this context, in-situ production of H 2 O 2 in the reaction medium with subsequent oxidation of the organic pollutants is of great interest.…”

“…Advanced oxidation processes (AOPs) have shown great potential for the treatment of industrial wastewaters [1][2][3][4][5][6][7]. These processes operate at near ambient temperature and pressure involving the generation of hydroxyl radicals in sufficient quantity to allow oxidizing the organic pollutants.…”

Enhancement of Fenton oxidation for removing organic matter from hypersaline solution by accelerating ferric system with hydroxylamine hydrochloride and benzoquinone

“…Currently, many technologies have been developed to improve Fenton oxidation for removing organic contaminants from aqueous solutions, such as photo-assisted (Al Momani et al, 2006;Kusic et al, 2006;Lau et al, 2002), microwave-enhanced (Liu et al, 2013;Yang et al, 2009), heating (Pliego et al, 2012;Zazo et al, 2011), and quinone (Chen and Pignatello, 1997;Gomez-Toribio et al, 2009) and hydroxylamine hydrochloride (HA) (Chen et al, 2011) redox cycling. As mentioned above, a major drawback of the Fenton system has been the accumulation and hydrolysisprecipitation of ferric ions, which could further slow down the whole Fenton process.…”