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14 pages, 3695 KiB

Open AccessArticle

Treatment of High-Strength Animal Industrial Wastewater Using Photo-Assisted Fenton Oxidation Coupled to Photocatalytic Technology

by Jae Hong Park, Dong Seok Shin and Jae Kwan Lee

Water 2019, 11(8), 1553; https://doi.org/10.3390/w11081553 - 27 Jul 2019

Cited by 8 | Viewed by 3572

Abstract

Animal wastewater is one of the wastewaters that has a color and is difficult to treat because it contains a large amount of non-degradable organic materials. The photo-assisted Fenton oxidation technique was applied to treat animal wastewater, and the optimal conditions of chemical [...] Read more.

Animal wastewater is one of the wastewaters that has a color and is difficult to treat because it contains a large amount of non-degradable organic materials. The photo-assisted Fenton oxidation technique was applied to treat animal wastewater, and the optimal conditions of chemical oxygen demands (COD) removal were analyzed according to changes in pH, ferrous ion, H₂O₂, and ultraviolet (UV) light intensity as a single experimental condition. Experimental results showed that, under the single-factor experimental conditions, the optimal conditions for degradation of animal wastewater were pH 3.5, Fe(II) 0.01 M, H₂O₂ 0.1 M, light intensity 3.524 mW/m². Under the optimal conditions, COD removal efficiency was 91%, sludge production was 2.5 mL from 100 mL of solution, color removal efficiency was 80%, and coliform removal efficiency was 99.5%. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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13 pages, 1704 KiB

Open AccessArticle

Catalytic Efficiency of Red Mud for the Degradation of Olive Mill Wastewater through Heterogeneous Fenton’s Process

by Eva Domingues, Nelson Assunção, João Gomes, Daniela V. Lopes, Jorge R. Frade, Margarida J. Quina, Rosa M. Quinta-Ferreira and Rui C. Martins

Water 2019, 11(6), 1183; https://doi.org/10.3390/w11061183 - 6 Jun 2019

Cited by 29 | Viewed by 4432

Abstract

Olive mill wastewater is a challenging effluent, especially due to its toxicity related to the presence of phenolic compounds. Fenton’s process was analysed on the abatement of phenolic acids typically found in this kind of effluents. To overcome the main drawback of Fenton’s [...] Read more.

Olive mill wastewater is a challenging effluent, especially due to its toxicity related to the presence of phenolic compounds. Fenton’s process was analysed on the abatement of phenolic acids typically found in this kind of effluents. To overcome the main drawback of Fenton’s process, a waste from the aluminium industry commonly called red mud was used as a heterogeneous source of iron. The adsorption of simulated effluent on the red mud was negligible. Therefore, the degradation of phenolic acids during Fenton’s process was due to oxidation by hydroxyl radicals. The amount of red mud and hydrogen peroxide were optimized regarding phenolic acids degradation. The optimal conditions leading to the highest removal of contaminants (100% of phenolic acids degradation and 25% of mineralization after 60 min of reaction) were 1 g/L of catalyst and 100 mg/L of hydrogen peroxide. The possibility of recovering treated water for agricultural purposes was evaluated by assessing the toxic impact over a wide range of species. The toxicity observed for the treated samples was mainly related to the residual hydrogen peroxide remaining after treatment. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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15 pages, 3150 KiB

Open AccessArticle

Effect of Different Radiation Sources and Noble Metal Doped onto TiO₂ for Contaminants of Emerging Concern Removal

by Rui C. Martins, Eva Domingues, Morgana Bosio, Margarida J. Quina, Marta Gmurek, Rosa M. Quinta-Ferreira and João Gomes

Water 2019, 11(5), 894; https://doi.org/10.3390/w11050894 - 28 Apr 2019

Cited by 12 | Viewed by 3300

Abstract

Water scarcity is a worldwide problem boosted by global warming and pollution of anthropogenic origin. The contaminants of emerging concern in water sources are increasing due to the inefficiency of conventional wastewater treatments, and these should be mitigated. Advanced oxidation processes appear as [...] Read more.

Water scarcity is a worldwide problem boosted by global warming and pollution of anthropogenic origin. The contaminants of emerging concern in water sources are increasing due to the inefficiency of conventional wastewater treatments, and these should be mitigated. Advanced oxidation processes appear as suitable solutions for decontamination. The photocatalytic oxidation of the mixture of sulfamethoxazole, carbamazepine and lorazepam was investigated. TiO₂ modified by Ag and TiO₂ modified by Pd were used as photocatalysts to improve photoactivity. The impact of light wavelengths was examined using UVA and visible radiation as well as natural sunlight. Visible light revealed the lowest ability for decontamination in 60 min of irradiation through Ag and Pd–TiO₂ photocatalytic oxidation. On the other hand, UVA and sunlight in the presence of photocatalysts were able to totally remove the contaminants. This can be related to the high production of reactive oxidative species at those conditions. The increase of the noble metal load promotes the improvement of the decontamination efficiency. The kinetic rate was analyzed for UVA and sunlight radiation for different photocatalytic conditions. The presence of a natural light source without energy costs leads to an increase in the pseudo-first-order kinetic constant. Sunlight radiation with a suitable photocatalyst can be a very good option for water decontamination. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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14 pages, 3913 KiB

Open AccessArticle

A Study of the Performance of Dielectric Barrier Discharge under Different Conditions for Nitrobenzene Degradation

by Muhammad Imran Nawaz, Chengwu Yi, Prince Junior Asilevi, Tingting Geng, Muhammad Aleem, Abdul Mannan Zafar, Ahmad Azeem and Huijuan Wang

Water 2019, 11(4), 842; https://doi.org/10.3390/w11040842 - 22 Apr 2019

Cited by 10 | Viewed by 4244

Abstract

Water scarcity and water contamination due to the extensive use of organic compounds in industries trigger us to adopt modern techniques for wastewater treatment. In this research, we developed a new dielectric barrier discharge (DBD) system which was evaluated for the degradation of [...] Read more.

Water scarcity and water contamination due to the extensive use of organic compounds in industries trigger us to adopt modern techniques for wastewater treatment. In this research, we developed a new dielectric barrier discharge (DBD) system which was evaluated for the degradation of nitrobenzene in water under different experimental arrangements. DBD produces an enormous amount of active species like O₃, ^•O, O₂⁺ and O₂⁻ and ^•OH to degrade the pollutants. In this study, NB (Nitrobenzene) was treated from wastewater by changing the gas flow rate, adopting different carrier gas, by adding inhibitors and promoters and the effect of applied voltage on the production of active species to check the effectiveness of the DBD system. The DBD system was evaluated based on input power, degradation efficiency and energy yield compared with other advanced oxidation processes. The energy yield of the DBD system was 1.253 mg/kWh for the degradation of 20 mg/L of NB to 75% in 60 min with the discharge power of 0.538 W, which displays better results in comparison with the other AOPs regarding energy yield and the degradation efficiency of the pollutant. The results illustrate the significance of the system and further suggest its application to industrial-scale treatment. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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17 pages, 3351 KiB

Open AccessArticle

Impact of Advanced Oxidation Products on Nanofiltration Efficiency

by Renata Żyłła, Rafał Milala, Irena Kamińska, Marcin Kudzin, Marta Gmurek and Stanisław Ledakowicz

Water 2019, 11(3), 541; https://doi.org/10.3390/w11030541 - 15 Mar 2019

Cited by 4 | Viewed by 3236

Abstract

The aim of the work was to determine the influence of salicylic acid (SA) oxidation products on the effectiveness of their further removal in the membrane filtration process. Two commercial polyamide-based polymer membranes, HL (GE Osmonics) and TS80 (TriSep^TM), were used [...] Read more.

The aim of the work was to determine the influence of salicylic acid (SA) oxidation products on the effectiveness of their further removal in the membrane filtration process. Two commercial polyamide-based polymer membranes, HL (GE Osmonics) and TS80 (TriSep^TM), were used and characterized by SEM microscopic analysis, contact angles, and free surface energy. The products of salicylic acid oxidation, 2,3- and 2,5-dihydroxybenzoic acid and catechol, were determined and their impact on the removal of unreacted salicylic acid in the nanofiltration process was investigated. It was also checked to what extent and why they were retained or not by the membranes. The results of the research have shown that the main product of salicylic acid oxidation, 2,3-dihydroxybenzoic acid, has a negative impact on the retention of salicylic acid in the nanofiltration stage, while the other product, catechol, improves SA retention. The determined values of contact angles correlate well with solubility (S) of the tested compounds, which increases in the following order S_SA < S_2,3-DHBA < S_CAT, while the contact angle of the membrane decreases. Nevertheless, it has been shown that some oxidation products can penetrate the environment due to poorer membrane separation properties of these products. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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12 pages, 2262 KiB

Open AccessArticle

Brine Recycling from Industrial Textile Wastewater Treated by Ozone. By-Products Accumulation. Part 1: Multi Recycling Loop

by Lucyna Bilińska, Kazimierz Blus, Marta Gmurek and Stanisław Ledakowicz

Water 2019, 11(3), 460; https://doi.org/10.3390/w11030460 - 5 Mar 2019

Cited by 22 | Viewed by 4645

Abstract

The “reactive” dyeing of textiles requires an application of low-molecular-weight salts (LMWS), such as NaCl or Na₂SO₄, as necessary auxiliary agents. LMWS acts only as a remediation factor and remains in the dyeing effluents constitute brine. The main goal [...] Read more.

The “reactive” dyeing of textiles requires an application of low-molecular-weight salts (LMWS), such as NaCl or Na₂SO₄, as necessary auxiliary agents. LMWS acts only as a remediation factor and remains in the dyeing effluents constitute brine. The main goal of the presented study was to investigate the application of ozone technology for industrial textile wastewater highly polluted by LMWS. The study was divided into two parts. In Part 1, by-products accumulated during multi-recycling of the same wastewater was investigated. While Part 2 was devoted to the scaling up of ozonation process, Part 1 concerns the efficiency of textile wastewater ozonation carried out as a repeatable process. The sequence of wastewater treatment and textile dyeing was repeated four times in a closed loop using the same process water. Although the wastewater decolorization was efficient in the subsequent ozonation cycles, some adverse effects, such as an increase in chemical oxygen demand (COD) and self-buffering at pH 9.5–10.0, were suggested the accumulation of by-products. The preliminary detection of by-products by thin layer chromatography (TLC) revealed phenol and naphthol derivatives as the transformation products (TPs) of ozonation. Dyeing of cotton using purified wastewater (brine) resulted in very good DE_CMC color matching parameters (under 1.16), but only in the first recycling loop, and then the TPs affected the process. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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16 pages, 5898 KiB

Open AccessArticle

NiO-NiFe₂O₄-rGO Magnetic Nanomaterials for Activated Peroxymonosulfate Degradation of Rhodamine B

by Xiaochen Xu, Yanfang Li, Guoquan Zhang, Fenglin Yang and Ping He

Water 2019, 11(2), 384; https://doi.org/10.3390/w11020384 - 22 Feb 2019

Cited by 36 | Viewed by 6919

Abstract

Magnetic spinel ferrites that act as heterogeneous catalysts and generate powerful radicals from peroxymono-sulfate (PMS) for the degradation of organic pollutants have received much attention in recent years due to the characteristic of environmental benefits. In this study, NiO-NiFe₂O₄-rGO [...] Read more.

Magnetic spinel ferrites that act as heterogeneous catalysts and generate powerful radicals from peroxymono-sulfate (PMS) for the degradation of organic pollutants have received much attention in recent years due to the characteristic of environmental benefits. In this study, NiO-NiFe₂O₄-rGO magnetic nanomaterials were synthesized using a calcinated Ni-Fe-LDH-rGO precursor. The morphology, structure, and chemical constitution were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), N₂ adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM). The catalytic performance of NiO-NiFe₂O₄-rGO nanoparticles was thoroughly evaluated for peroxymonosulfate (PMS) activation and its removal of rhodamine B (RhB) from water. The influence of different process parameters on the RhB degradation efficiency was examined. Further, the catalytic stability was evaluated. Under optimized conditions, the NiO-NiFe₂O₄-rGO/PMS system was very efficient; RhB fully degraded after 40 min at room temperature. Quenching experiments and electronic paramagnetic resonance (EPR) results suggested that SO₄⁻· and OH· were the main active species in the degradation process. Moreover, NiO-NiFe₂O₄-rGO catalyst was stable without any apparent activity loss after three cycling runs. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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25 pages, 3100 KiB

Open AccessArticle

Analysis of a Hybrid Suspended-Supported Photocatalytic Reactor for the Treatment of Wastewater Containing Benzothiazole and Aniline

by Cristian Ferreiro, Natalia Villota, José Ignacio Lombraña, María J. Rivero, Verónica Zúñiga and José Miguel Rituerto

Water 2019, 11(2), 337; https://doi.org/10.3390/w11020337 - 16 Feb 2019

Cited by 25 | Viewed by 4809

Abstract

In this work, a study of the main operating variables affecting TiO₂/UV photocatalysis was carried out. The treatment of an industrial effluent containing aniline and benzothiazole from the manufacture of accelerants for vulcanization was performed in a TiO₂-supported commercial [...] Read more.

In this work, a study of the main operating variables affecting TiO₂/UV photocatalysis was carried out. The treatment of an industrial effluent containing aniline and benzothiazole from the manufacture of accelerants for vulcanization was performed in a TiO₂-supported commercial photoreactor. The degradation of both contaminants was monitored by GC-MS analysis. The proposed experiments were able to properly identify the phenomenon of adsorption, as well as to improve the performance of the commercial photoreactor by adding small amounts of TiO₂ in suspension. The removal performance, durability of the photocatalytic material, and energy costs were analysed. The results showed that the use of suspensions intensifies the degradation obtaining an improvement of 23.15% with respect to the use of the supported catalyst. For an aniline and benzothiazole solution, the best operating conditions were found at pH = 12.0, introducing 60.0 mg L⁻¹ of suspended TiO₂ together with the existing supported catalyst. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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16 pages, 3993 KiB

Open AccessArticle

³¹P NMR Investigations on Roundup Degradation by AOP Procedures

by Marcin H. Kudzin, Renata Żyłła, Zdzisława Mrozińska and Paweł Urbaniak

Water 2019, 11(2), 331; https://doi.org/10.3390/w11020331 - 15 Feb 2019

Cited by 5 | Viewed by 4131

Abstract

The reactions of (N-(PhosphonoMethyl)Glycine) PMG with H₂O₂ in homogenous systems were investigated using ³¹P NMR (Nuclear Magnetic Resonance). These reactions were carried out in two reaction modes: without UV radiation and under UV radiation. The reactions of [...] Read more.

The reactions of (N-(PhosphonoMethyl)Glycine) PMG with H₂O₂ in homogenous systems were investigated using ³¹P NMR (Nuclear Magnetic Resonance). These reactions were carried out in two reaction modes: without UV radiation and under UV radiation. The reactions of PMG with H₂O₂ without UV radiation were carried out in two modes: the degradations of PMG (0.1 mmol) by means of 5–10 molar excess of hydrogen dioxide (PMG-H₂O₂ = 1:5 and 1:10) and the degradation of PMG (0.1 mmol) in homogenous Fenton reactions (PMG-H₂O₂-Fe²⁺ = 1:10:0.05 and 1:10:0.1). All reactions were carried out at ambient temperature, at pH 3.5, for 48 h. The reactions of PMG (in Roundup herbicide composition, 12 mmol) with H₂O₂ under UV radiation (254 nm) were carried out using 5 × molar excess of H₂O₂ (60 mmol), in the pH range of 2 ≤ pH ≤ 12, for 6 h. In this mode of PMG oxidation, the splitting of C-P was observed in the ratios dependent on the applied pH of the reaction mixture. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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9 pages, 1406 KiB

Open AccessArticle

Brine Recycling from Industrial Textile Wastewater Treated by Ozone. By-Products Accumulation. Part 2: Scaling-Up

by Lucyna Bilińska, Kazimierz Blus, Marta Gmurek, Renata Żyłła and Stanisław Ledakowicz

Water 2019, 11(2), 233; https://doi.org/10.3390/w11020233 - 30 Jan 2019

Cited by 7 | Viewed by 4036

Abstract

Extremely high volumes of salty wastewater are produced by textile manufacturers daily. Therefore, brine recycling from the wastewater should be regarded as a crucial issue within the textile industry. Ozonation was used in this two-part study as a purification method for industrial textile [...] Read more.

Extremely high volumes of salty wastewater are produced by textile manufacturers daily. Therefore, brine recycling from the wastewater should be regarded as a crucial issue within the textile industry. Ozonation was used in this two-part study as a purification method for industrial textile wastewater polluted by low-molecular-weight salts (LMWS). Part 1 revealed the accumulation of ozonation by-products in a multi-recycling system. The objective of Part 2 was the scaling-up of the process and the investigation of the occurrence of by-products. It was found that ozonation works well in an alkaline reaction medium, which was characteristic of the wastewater from a dye house; an almost complete color removal was achieved within 30 min of treatment. The brine that was produced from the wastewater treated by ozonation in a 20 L bubble column reactor was recycled successfully. Dyeing of cotton with five types of reactive dyes in various shades resulted in very good values of DE_CMC, which is the normative color matching parameter, and were between 0.15 and 1.2. The color fastness obtained for upcycled fabrics were satisfactory, and not worse than standard values. Although accumulation of the side products was detected in Part 1, the fabric discharges produced in the scaled-up process were free from carcinogenic amines and heavy metals. The study indicated that ozonation can be applied in the industry as a method for textile wastewater recycling. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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14 pages, 2192 KiB

Open AccessArticle

Study of the Degradation of Trimethoprim Using Photo-Fenton Oxidation Technology

by Qi Wang, Wenjing Pang, Yingdan Mao, Quan Sun, Pengfei Zhang, Qiang Ke, Hengguo Yu, Chuanjun Dai and Min Zhao

Water 2019, 11(2), 207; https://doi.org/10.3390/w11020207 - 25 Jan 2019

Cited by 23 | Viewed by 5361

Abstract

Trimethoprim is one of the representative drugs within the pharmaceutical and personal care products (PPCPs) group. The photo-Fenton oxidation technology was used to degrade trimethoprim in wastewater and the extent of degradation was analyzed by using high-performance liquid chromatography, then experimentally obtained the [...] Read more.

Trimethoprim is one of the representative drugs within the pharmaceutical and personal care products (PPCPs) group. The photo-Fenton oxidation technology was used to degrade trimethoprim in wastewater and the extent of degradation was analyzed by using high-performance liquid chromatography, then experimentally obtained the optimal conditions. Analysis of the experimental data showed that, under the single-factor experimental conditions, the optimal conditions for degradation were a pH of 4, an H₂O₂ concentration of 3.0 mmol/L, an FeSO₄ concentration of 0.06 mmol/L, an initial trimethoprim concentration of 0.0689 mmol/L, and an ultraviolet (UV) intensity (UVA) of 12 mW/cm². The interaction of pH and the concentration of H₂O₂ and Fe²⁺ have been further explored, it was obtained the following response surface results through the central composite design experiment: pH = 4.56, H₂O₂ concentration = 0.09 mmol/L, and Fe²⁺ concentration = 0.09 mmol/L. Under these conditions, it can be obtained a degradation rate of 99.95% after 6 min. There were similar results for three sets of parallel experiments, indicating that these simulation conditions were feasible. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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16 pages, 1274 KiB

Open AccessArticle

Treatment of Landfill Leachates with Combined Acidification/Coagulation and the Fe⁰/H₂O₂ Process

by Jan Bogacki, Piotr Marcinowski and Balkess El-Khozondar

Water 2019, 11(2), 194; https://doi.org/10.3390/w11020194 - 23 Jan 2019

Cited by 8 | Viewed by 4723

Abstract

One of the major environmental concerns associated with waste disposal is the large amount of generated landfill leachates (LL), which are considered a type of wastewater with a complex composition. There is an urgent need to find an effective LL treatment method. LL [...] Read more.

One of the major environmental concerns associated with waste disposal is the large amount of generated landfill leachates (LL), which are considered a type of wastewater with a complex composition. There is an urgent need to find an effective LL treatment method. LL were subjected to pretreatment followed by the Fe⁰/H₂O₂ process. Pretreatment efficiency was coagulation at pH 6.0 >> coagulation at pH 9.0 > acidification at pH 3.0. Coagulation at pH 6.0 in an optimal Fe³⁺ dose of 1000 mg/L decreased total organic carbon (TOC) from the initial concentration of 1061 mg/L to 491 mg/L while acidification to pH 3.0 decreased TOC to 824 mg/L. After acidification, the Fe⁰/H₂O₂ process with 8000/9200 mg/L Fe⁰/H₂O₂ reagent doses decreased TOC to 499 mg/L after a processing time of 60 min. Performance of the Fe⁰/H₂O₂ process after coagulation at pH 6.0 for optimal Fe⁰/H₂O₂ 8000/5540 mg/L reagent doses decreased TOC to 268 mg/L (75% TOC removal). Treatment of landfill leachates with combined process coagulation and Fe⁰/H₂O₂ also increased their susceptibility to biodegradation, expressed as the biochemical oxygen demand/chemical oxygen demand (BOD₅/COD) ratio from 0.13 to 0.43, allowing LL to be considered as susceptible to biodegradation. Fe⁰/H₂O₂ process kinetics was described. A statistical analysis confirmed the obtained results. The proposed method can be successfully applied for LL treatment. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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12 pages, 773 KiB

Open AccessFeature PaperArticle

Removal of Enteric Pathogens from Real Wastewater Using Single and Catalytic Ozonation

by João Gomes, Danilo Frasson, Rosa M. Quinta-Ferreira, Ana Matos and Rui C. Martins

Water 2019, 11(1), 127; https://doi.org/10.3390/w11010127 - 12 Jan 2019

Cited by 32 | Viewed by 4919

Abstract

Water scarcity is one of the main problems of this century. Water reclamation appears as an alternative due to the reuse of treated wastewater. Therefore, effluents treatment technologies (activated sludge, rotary biological discs, percolating beds) must be improved since they are not able [...] Read more.

Water scarcity is one of the main problems of this century. Water reclamation appears as an alternative due to the reuse of treated wastewater. Therefore, effluents treatment technologies (activated sludge, rotary biological discs, percolating beds) must be improved since they are not able to remove emerging contaminants such as enteric pathogens (bacteria and virus). These pollutants are difficult to remove from the wastewater and lead to adverse consequences to human health. Advanced oxidation processes, such as single and catalytic ozonation, appear as suitable complements to conventional processes. Catalytic ozonation was carried out using a low-cost material, a volcanic rock. Single and catalytic ozonation were capable of promoting total Escherichia coli removal from municipal wastewater after 90 min of contact. The presence of volcanic rock increases disinfection efficiency since E. coli regrowth was not observed. The identified viruses (Norovirus genotype I and II and JC virus) were completely removed using catalytic ozonation, whereas single ozonation was not able to eliminate JC virus even after 150 min of treatment. The higher performance of the catalytic process can be explained by the formation of hydroxyl radicals, proving that disinfection occurs in the liquid bulk and not due to adsorption at the volcanic rock. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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10 pages, 5571 KiB

Open AccessArticle

Treatment of Organics Contaminated Wastewater by Ozone Micro-Nano-Bubbles

by Zhiran Xia and Liming Hu

Water 2019, 11(1), 55; https://doi.org/10.3390/w11010055 - 30 Dec 2018

Cited by 69 | Viewed by 9435

Abstract

The efficiency of ozone for the treatment of organics contaminated wastewater is limited by its slow dissolution rate and rapid decomposition in the aqueous phase. Micro-nano-bubbles (MNBs) are a novel method to prolong the reactivity of the ozone in the aqueous phase, thereby [...] Read more.

The efficiency of ozone for the treatment of organics contaminated wastewater is limited by its slow dissolution rate and rapid decomposition in the aqueous phase. Micro-nano-bubbles (MNBs) are a novel method to prolong the reactivity of the ozone in the aqueous phase, thereby accelerating the treatment of the contaminant. In this study, the effects of pH and salinity on the treatment efficiency of ozone MNBs were examined. The highest efficiency was observed in weak acidic conditions and an increase in salinity enhanced the treatment efficiency significantly. Furthermore, the treatment of highly saline industrial wastewater as well as multi-contaminant groundwater containing persistent organics were also investigated. Treatment using ozone MNBs had a considerable effect on wastewaters that are otherwise difficult to treat using other methods; hence, it is a promising technology for wastewater treatment. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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26 pages, 4224 KiB

Open AccessArticle

Treatment of Eutrophic Water and Wastewater from Valsequillo Reservoir, Puebla, Mexico by Means of Ozonation: A Multiparameter Approach

by J. Tabla-Hernández, P. F. Rodríguez-Espinosa, A. G. Hernandez-Ramirez, Jorge A. Mendoza-Pérez, E. R. Cano-Aznar and E. Martínez-Tavera

Water 2018, 10(12), 1790; https://doi.org/10.3390/w10121790 - 6 Dec 2018

Cited by 8 | Viewed by 4239

Abstract

The present work aims to elucidate the possibility of injecting ozone into surface waters combined with urban wastewaters in order to improve the water quality of the High Atoyac Sub-basin (HAS) in Central Mexico. For this purpose, twenty physicochemical parameters, eight heavy metals, [...] Read more.

The present work aims to elucidate the possibility of injecting ozone into surface waters combined with urban wastewaters in order to improve the water quality of the High Atoyac Sub-basin (HAS) in Central Mexico. For this purpose, twenty physicochemical parameters, eight heavy metals, seven organic compounds, and one biological indicator were assessed in water from different sites of the studied area (the Alseseca River, the Atoyac River and the Valsequillo Reservoir). Results demonstrated that O₃ injection led to the decrease of the aromatic fraction of organic molecules since the Spectral Absorption Coefficient at 254 nanometers (SAC₂₅₄) reduction was found to be 31.7% in the Valsequillo Reservoir water samples. Maximum Chemical Oxygen Demand (COD) removal was observed to be 60.2% from the Alseseca River with a 0.26 mg O₃/mg initial COD dose. Among all the phthalates studied in the present work, Di(2-ethylhexyl) phthalate (DEHP) exhibited the highest concentration (5.8 μg/L in the Atoyac River). Treatment with O₃ was not effective in eliminating fecal coliforms (FC) in waters that host high organic matter (OM) loads as opposed to waters with low OM. After the injection of 4.7 mg O₃/mg COD in the VO₃-AT water sample, a 90% removal of Iron (Fe) and Aluminum (Al) was registered; while Manganese (Mn), Nickel (Ni), Zinc (Zn), and Cooper (Cu) showed a 73%, 67%, 81%, and 80% removal, respectively; Chromium (Cr) registered the highest removal (~100%). The present work demonstrated that while finding a suitable O₃ dose to improve the quality of water in the HAS, the 5-days Biochemical Oxygen Demand (BOD₅)/COD ratio (i.e., biodegradability) is more important than the overall OM removal percentage proving that O₃ injection is a feasible process for the treatment of eutrophic waters from HAS. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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Review

Jump to: Research

35 pages, 766 KiB

Open AccessReview

N–TiO₂ Photocatalysts: A Review of Their Characteristics and Capacity for Emerging Contaminants Removal

by João Gomes, João Lincho, Eva Domingues, Rosa M. Quinta-Ferreira and Rui C. Martins

Water 2019, 11(2), 373; https://doi.org/10.3390/w11020373 - 21 Feb 2019

Cited by 142 | Viewed by 9643

Abstract

Titanium dioxide is the most used photocatalyst in wastewater treatment; its semiconductor capacity allows the indirect production of reactive oxidative species. The main drawback of the application of TiO₂ is related to its high band-gap energy. The nonmetal that is most often [...] Read more.

Titanium dioxide is the most used photocatalyst in wastewater treatment; its semiconductor capacity allows the indirect production of reactive oxidative species. The main drawback of the application of TiO₂ is related to its high band-gap energy. The nonmetal that is most often used as the doping element is nitrogen, which is due to its capacity to reduce the band-gap energy at low preparation costs. There are multiple and assorted methods of preparation. The main advantages and disadvantages of a wide range of preparation methods were discussed in this paper. Different sources of N were also analyzed, and their individual impact on the characteristics of N–TiO₂ was assessed. The core of this paper was focused on the large spectrum of analytical techniques to detect modifications in the TiO₂ structure from the incorporation of N. The effect of N–TiO₂ co-doping was also analyzed, as well as the main characteristics that are relevant to the performance of the catalyst, such as its particle size, surface area, quantum size effect, crystalline phases, and the hydrophilicity of the catalyst surface. Powder is the most used form of N–TiO₂, but the economic benefits and applications involving continuous reactors were also analyzed with supported N–TiO₂. Moreover, the degradation of contaminants emerging from water and wastewater using N–TiO₂ and co-doped TiO₂ was also discussed. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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29 pages, 3075 KiB

Open AccessFeature PaperReview

Application of Advanced Oxidation Processes for the Treatment of Recalcitrant Agro-Industrial Wastewater: A Review

by Carlos Amor, Leonilde Marchão, Marco S. Lucas and José A. Peres

Water 2019, 11(2), 205; https://doi.org/10.3390/w11020205 - 25 Jan 2019

Cited by 185 | Viewed by 16895

Abstract

Agro-industrial wastewaters are characterized by the presence of multiple organic and inorganic contaminants of environmental concern. The high pollutant load, the large volumes produced, and the seasonal variability makes the treatment of these wastewaters an environmental challenge. A wide range of wastewater treatment [...] Read more.

Agro-industrial wastewaters are characterized by the presence of multiple organic and inorganic contaminants of environmental concern. The high pollutant load, the large volumes produced, and the seasonal variability makes the treatment of these wastewaters an environmental challenge. A wide range of wastewater treatment processes are available, however the continuous search for cost-effective treatment methods is necessary to comply with the legal limits of release in sewer systems and/or in natural waters. This review presents a state-of-the-art of the application of advanced oxidation processes (AOPs) to some worldwide generated agro-industrial wastewaters, such as olive mill, winery and pulp mill wastewaters. Studies carried out just with AOPs or combined with physico-chemical or biological treatments were included in this review. The main remarks and factors affecting the treatment efficiency such as chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), total organic carbon (TOC), and total polyphenols removal are discussed. From all the studies, the combination of processes led to better treatment efficiencies, regardless the wastewater type or its physico-chemical characteristics. Full article

(This article belongs to the Special Issue Advanced Oxidation Technologies in Industrial Wastewater Treatment)

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