H2O2 Based Oxidation Processes for the Treatment of Real High Strength Aqueous Wastes

Collivignarelli, Maria Cristina; Pedrazzani, Roberta; Sorlini, Sabrina; Abbà, Alessandro; Bertanza, Giorgio

doi:10.3390/su9020244

Cited by 52 publications

(28 citation statements)

References 33 publications

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“…A set of experiments were carried out at 70 °C to analyze the relationship between the system pH and the adsorption of organic compounds over γ-Al 2 O 3 (see Table 4). Trials were made as a function of the point of zero charge (PZC) of γ-Al 2 O 3 (7)(8)(9), corresponding to the pH at which its surface is neutral [57], [58]. The pH of the experiments was controlled by adding H 2 SO 4 or NaOH to the reaction volume; since γ-Al 2 O 3 tends to dissolve in strong systems (either acidic or basic), these trials were performed within a pH range that was kept between 3 and 10.…”

Section: Estimation Of Toc Reduction By Adsorptionmentioning

confidence: 99%

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Kinetic modeling of a heterogeneous Fenton-type oxidative treatment of complex industrial effluent

et al. 2018

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This work proposes a kinetic model for the reactions involved in the heterogeneous copper-based Fenton-type oxidation of mixed recalcitrant compounds in a real industrial effluent from the alkaline sulfite treatment of wood. This kind of treatment is unusual in this industry due to the complexity of the effluents and the high costs involved in total mineralization of the organic matter. Nevertheless, conversion of recalcitrant to degradable compounds and catalyst recovery can make the difference. The complexity of the effluent and the great number of compounds formed as intermediates, make extremely difficult the identification and quantification of the individual reactions that occur during oxidation. To solve this drawback TOC parameter was used as a representative measurement. To verify the level of TOC degradation produced by the heterogeneous catalysis reaction, experiences of homogeneous catalysis and adsorption were accomplished. The studied temperature range was 45-80 °C. A "two-step" kinetic model was applied to TOC reduction in heterogeneous and homogeneous oxidations, admitting two sequential steps of oxidation: a first fast stage ("seconds stage") followed by a slow one ("minutes stages"). Kinetic constants were obtained for both processes and activation energies were also determined for the "minutes stage" step (33.17 kJ/mol and 15.13 kJ/mol, respectively). Homogeneous catalysis studies confirm mass transfer limitations in heterogeneous oxidations. Experiences of adsorption of organic matter on CuO/γ-Al 2 O 3 catalyst demonstrated that this phenomenon is exothermic and cannot be neglected. The activation energy of adsorption was determined as 7.32 kJ/mol. Catalysts were characterized through SEM, EDS, XRD, FTIR, and TGA. Graphical Abstract

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Section: Estimation Of Toc Reduction By Adsorptionmentioning

confidence: 99%

“…These processes differ from each other in the source of radicals HO·, which is their main feature. Hydroxyl radicals (HO·) present high reactivity and low selectivity during oxidation [1], [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Kinetic modeling of a heterogeneous Fenton-type oxidative treatment of complex industrial effluent

et al. 2018

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“…Disinfection is essential and can guarantee the limit imposed for the E. coli [21]. Other treatments can be added in order to avoid problem with acute toxicity, surfactants and Sodium Adsorption Ratio (SAR) [22][23][24][25] In case of indirect reuse the limits for COD, BOD 5 , SS, nitrogen and phosphorus, E. coli to be respected in Italy, are intermediate between those imposed by the D.M. 185/2003 or Regional Regulation and those of Legislative Decree no.…”

Section: Methodsmentioning

confidence: 99%

Water reuse as a secure pathway to deal with water scarcity

et al. 2020

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An adequate access to water supply systems is crucial for a sustainable future. Climate change is expected to increase water shortage problems worldwide. Reuse/recycling of treated wastewater for domestic and/or agricultural purposes can be considered an interesting water supply: it is independent from seasonal drought and meteorological variability and able to cover the peak of water demand. In the case of direct reuse, the parameter of treated water must comply with the reuse limits for biological oxygen demand, chemical oxygen demand and suspended solids. In case of indirect reuse, the regulatory approach changes as the dilution ratio between discharge and flow of the irrigation canal is taken into account too. There are many interventions that are considered useful for the purpose of promoting the development of an enhanced water recovery and recycling: legislation improvements, modification in the water storage management, prevention in pollution discharged into sewerage systems, improving the efficiency of WWTPs, incentive the adoption of rainwater storage tanks and interventions for the separation of gray water, establish a “blue certificate” for financing investments. In the present paper those aspects are analysed referring to some cases found in an Italian region.

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“…For instance, when solvent extraction is applied, the toxicity of the solvent is an important factor, as traces of solvent may remain within the treated soil [1], thereby compromising its quality. On the other hand, for chemical oxidation, reagent costs have to be carefully evaluated during the design phase [2]; for instance, in Fenton's process, high carbonate and bicarbonate concentrations in the soil (as well as the organic matter) can lead to a high dosage of reagents [3], with respect to the stoichiometric amount. Furthermore, the composition of the soil (in terms of granulometry) can also affect the decontamination process; to give an example, soils characterized by a high content of silt and clay cannot be treated effectively with cheaper biological processes, or by soil vapor extraction, because of their low air permeability.…”

Section: Introductionmentioning

confidence: 99%

Wet Oxidation of Fine Soil Contaminated with Petroleum Hydrocarbons: A Way towards a Remediation Cycle

et al. 2018

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The aim of this experimental study was to assess the feasibility of using a wet oxidation (WO) process for treating fine soil with a high level of total petroleum hydrocarbons (TPHs). Two samples of soil were spiked with two different contaminants (motor oil, and motor oil + diesel). The samples were subjected to a WO bench plant test, where the effect of the main process parameters (i.e., temperature and reaction time) on the removal of TPHs was investigated. Results show that the WO process is effective for the decontamination of hydrocarbons, and a strong reduction (>85%) can be obtained with the typical working conditions of a full-scale plant (temperature = 250 • C, reaction time = 30 min). The solid residue resulting from the WO process was characterized in order to evaluate the recovery options. In terms of chemical characterization, the contents of the pollutants comply with the Italian regulations for commercial and industrial site use. Moreover, the results of the leaching test suggested that these residues could be reused for ceramic and brick manufacturing processes.In addition, it must be taken into account that due to the tendency of contaminants to accumulate in the fine fraction of soil [4], in many cases, that fraction is not treated, but instead directly landfilled, and the remediation cycle is not completed; something that occurs, as reported by Dermont et al. [5], in soil washing treatment. Another aspect to be taken into account is the change in the partition of the contaminant amongst the different fractions of the soils due to the washing process [6].In recent times, the European Commission has adopted an ambitious Circular Economy Package [7], aiming to stimulate Europe's transition towards a circular economy. The proposed actions will contribute to "closing the loop" of product life cycles through greater recycling and reuse, and will bring benefits for both the environment and the economy. Therefore, the technicians are motivated to improve or find alternative remediation technologies finalized to close the remediation cycle, and give a new life to waste.A technology that can be useful in reaching the aforementioned targets is the wet oxidation (WO) process, which is reliable and effective in the treatment of a wide spectrum of organic aqueous waste, even toxic waste, produced by various branches of industrial activity [8,9], and sewage sludge [10].Typical treatment conditions for sludge and hazardous wastes reported in the literature are as follows: 200-325 • C for temperature; 5000-17,500 kPa for pressure; and 15-120 min for the reaction time. The preferred COD load ranges from 10-80 kg·m −3 .One of the biggest advantages related to the WO process is that decontamination is obtained with low polluting output gases, composed mainly of CO 2 , water steam, and oxygen, without hazardous by-products and low organic content in the final residue [8,11,12]. In addition, the WO effluent can be conveniently treated in a conventional wastewater treatment plant because of its high biodegradability...

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H2O2 Based Oxidation Processes for the Treatment of Real High Strength Aqueous Wastes

Cited by 52 publications

References 33 publications

Kinetic modeling of a heterogeneous Fenton-type oxidative treatment of complex industrial effluent

Kinetic modeling of a heterogeneous Fenton-type oxidative treatment of complex industrial effluent

Water reuse as a secure pathway to deal with water scarcity

Wet Oxidation of Fine Soil Contaminated with Petroleum Hydrocarbons: A Way towards a Remediation Cycle

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