Research

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17 pages, 5189 KiB

Open AccessArticle

Design, Scale-Up, and Construction of Drinking Water Recarbonization Fluidized Bed Reactor System

by Jozef Dudáš, Ján Derco, Tomáš Kurák, Nikola Šoltýsová, Ľudovít Jelemenský and Martin Vrabeľ

Processes 2022, 10(10), 2068; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10102068 - 13 Oct 2022

Cited by 1 | Viewed by 1337

The lack of calcium and magnesium in drinking water affects people’s health, especially cardiovascular and oncologic diseases, and causes corrosion problems. The aim of this paper is to present the methodology of the design, scale-up, and construction of a fluidized bed reactor (FBR) [...] Read more.

The lack of calcium and magnesium in drinking water affects people’s health, especially cardiovascular and oncologic diseases, and causes corrosion problems. The aim of this paper is to present the methodology of the design, scale-up, and construction of a fluidized bed reactor (FBR) system for drinking water recarbonization with biogenic elements in real conditions. Half-calcined dolomite (HCD) in combination with CO₂ was identified as a suitable source of Mg²⁺ and Ca²⁺. The experimental results confirmed that an FBR reactor with a water tank is an efficient system for Mg and Ca²⁺ ion concentrate production. The main process parameters and dimensions of the equipment were determined based on the experimental data and the data obtained showed that the system can be used in real conditions to produce Mg²⁺ and Ca²⁺ ions concentrate, which is mixed with soft water in required proportions. The FBR with an internal diameter of 0.16 m and a total height of 3.7 m was designed. The proposed methodology of the recarbonization process design was used in a further system scale-up for a ten times larger capacity. Long-term experiments indicate that the HCD recarbonization process is robust and can return to the steady state even after significant changes in the process parameters for providing the desired concentration of Mg²⁺ and Ca²⁺ ions in drinking water. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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12 pages, 2972 KiB

Open AccessArticle

Influence of Post- and Pre-Acid Treatment during Hydrothermal Carbonization of Sewage Sludge on P-Transformation and the Characteristics of Hydrochar

by Vicky Shettigondahalli Ekanthalu, Satyanarayana Narra, Tommy Ender, Edward Antwi and Michael Nelles

Processes 2022, 10(1), 151; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10010151 - 12 Jan 2022

Cited by 10 | Viewed by 2324

Abstract

Phosphorus (P) recovery from alternative P-rich residues is essential to meet the growing demands of food production globally. Despite sewage sludge being a potential source for P, its direct application on agricultural land is controversial because of the obvious concerns related to heavy [...] Read more.

Phosphorus (P) recovery from alternative P-rich residues is essential to meet the growing demands of food production globally. Despite sewage sludge being a potential source for P, its direct application on agricultural land is controversial because of the obvious concerns related to heavy metals and organic pollutants. Further, most of the available P recovery and sludge management technologies are cost-intensive as they require mandatory dewatering of sewage sludge. In this regard, hydrothermal carbonization (HTC) has gained great attention as a promising process to effectively treat the wet sewage sludge without it having to be dewatered, and it simultaneously enables the recovery of P. This study was conducted to analyse and compare the influence of acid (H₂SO₄) addition during and after HTC of sewage sludge on P leaching and the characteristics of hydrochar. The obtained results suggested that despite using the same amount of H₂SO₄, P leaching from solid to liquid phase was significantly higher when acid was used after the HTC of sewage sludge in comparison with acid utilization during the HTC process. After HTC, the reduction in acid-buffering capacity of sewage sludge and increase in solubility of phosphate precipitating metal ions had a greater influence on the mobilization of P from solid to liquid phase. In contrast, utilization of H₂SO₄ in different process conditions did not have a great influence on proximate analysis results and calorific value of consequently produced hydrochar. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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10 pages, 1539 KiB

Open AccessFeature PaperArticle

Concentration Polarization Quantification and Minimization in Cork Process Wastewater Ultrafiltration by an Ozone Pretreatment

by Miguel Minhalma, Maria Norberta de Pinho and Joaquin R. Dominguez

Processes 2021, 9(12), 2182; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9122182 - 03 Dec 2021

Cited by 1 | Viewed by 1218

Abstract

Concentration polarization and membrane fouling have been identified as the main problems during the ultrafiltration treatment of cork processing wastewaters. These problems drastically reduce the permeate fluxes and, therefore, their potential applications. In this work, a soft ozonation pretreatment was applied to minimize [...] Read more.

Concentration polarization and membrane fouling have been identified as the main problems during the ultrafiltration treatment of cork processing wastewaters. These problems drastically reduce the permeate fluxes and, therefore, their potential applications. In this work, a soft ozonation pretreatment was applied to minimize these undesirable effects. A new systematic study was carried out for membranes with different molecular weight cut-offs and at different operating conditions to monitor and quantify the concentration polarization caused by the wastewater’s remaining ozonated compounds. Film theory was used to correlate the mass transfer coefficient, k, and the intrinsic rejection coefficient, f′, with the resistance introduced by concentration polarization. The ultrafiltration treatment was carried out under varying hydrodynamic operating conditions (circulating flow rates of 100–200 L/h) and transmembrane pressures (1–3 bar) for a set of four cellulose acetate membranes covering a wide range of molecular weight cut-offs (5000–100,000 Da) and hydraulic permeabilities (25–110 kg/h/m²/bar). The ozone pretreatment (at wastewater pH) reduced the phenolic content selectively (direct oxidation) by more than 50%, reducing membrane fouling and concentration polarization and increasing permeate fluxes (by 22–45%) and mass transfer coefficients (up to six times). Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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16 pages, 3071 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Optimization and Modeling of Ammonia Nitrogen Removal from High Strength Synthetic Wastewater Using Vacuum Thermal Stripping

by Arif Reza and Lide Chen

Processes 2021, 9(11), 2059; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9112059 - 17 Nov 2021

Cited by 5 | Viewed by 2713

Abstract

Waste streams with high ammonia nitrogen (NH₃-N) concentrations are very commonly produced due to human intervention and often end up in waterbodies with effluent discharge. The removal of NH₃-N from wastewater is therefore of utmost importance to alleviate water [...] Read more.

Waste streams with high ammonia nitrogen (NH₃-N) concentrations are very commonly produced due to human intervention and often end up in waterbodies with effluent discharge. The removal of NH₃-N from wastewater is therefore of utmost importance to alleviate water quality issues including eutrophication and fouling. In the present study, vacuum thermal stripping of NH₃-N from high strength synthetic wastewater was conducted using a rotary evaporator and the process was optimized and modeled using response surface methodology (RSM) and RSM–artificial neural network (ANN) approaches. RSM was first employed to evaluate the process performance using three independent variables, namely pH, temperature (°C) and stripping time (min), and the optimal conditions for NH₃-N removal (response) were determined. Later, the obtained data from the designed experiments of RSM were used to train the ANN for predicting the responses. NH₃-N removal was found to be 97.84 ± 1.86% under the optimal conditions (pH: 9.6, temperature: 65.5 °C, and stripping time: 59.6 min) and was in good agreement with the values predicted by RSM and RSM–ANN models. A statistical comparison between the models revealed the better predictability of RSM–ANN than that of the RSM. To the best of our knowledge, this is the first attempt comparing the RSM and RSM–ANN in vacuum thermal stripping of NH₃-N from wastewater. The findings of this study can therefore be useful in designing and carrying out the vacuum thermal stripping process for efficient removal of NH₃-N from wastewater under different operating conditions. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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18 pages, 2874 KiB

Open AccessArticle

Design of Polymer-Embedded Heterogeneous Fenton Catalysts for the Conversion of Organic Trace Compounds

by Christoph Horn, Stephanie Ihmann, Felix Müller, Doris Pospiech, Konstantin B. L. Borchert, Rolf Hommel, Kaite Qin, Kai Licha, Peter J. Allertz and Marco Drache

Processes 2021, 9(6), 942; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9060942 - 26 May 2021

Viewed by 1746

Abstract

Advanced oxidation processes are the main way to remove persistent organic trace compounds from water. For these processes, heterogeneous Fenton catalysts with low iron leaching and high catalytic activity are required. Here, the preparation of such catalysts consisting of silica-supported iron oxide (Fe [...] Read more.

Advanced oxidation processes are the main way to remove persistent organic trace compounds from water. For these processes, heterogeneous Fenton catalysts with low iron leaching and high catalytic activity are required. Here, the preparation of such catalysts consisting of silica-supported iron oxide (Fe₂O₃/SiO_x) embedded in thermoplastic polymers is presented. The iron oxide catalysts are prepared by a facile sol–gel procedure followed by thermal annealing (calcination). These materials are mixed in a melt compounding process with modified polypropylenes to stabilize the Fe₂O₃ catalytic centers and to further reduce the iron leaching. The catalytic activity of the composites is analyzed by means of the Reactive Black 5 (RB5) assay, as well as by the conversion of phenol which is used as an example of an organic trace compound. It is demonstrated that embedding of silica-supported iron oxide in modified polypropylene turns the reaction order from pseudo-first order (found for Fe₂O₃/SiO_x catalysts), which represents a mainly homogeneous Fenton reaction, to pseudo-zeroth order in the polymer composites, indicating a mainly heterogeneous, surface-diffusion-controlled process. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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10 pages, 2996 KiB

Open AccessArticle

Efficient Removal of Cr (VI) with Biochar and Optimized Parameters by Response Surface Methodology

by Hao Peng, Jing Guo, Hongzhi Qiu, Caiqiong Wang, Chenyu Zhang, Zhihui Hao, Yating Rao and Yanhong Gong

Processes 2021, 9(5), 889; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9050889 - 18 May 2021

Cited by 11 | Viewed by 2094

Abstract

A highly efficient reduction process of Cr (VI) with biochar was conducted in this paper. The results showed that nearly 100% Cr (VI) was reduced at selected reaction conditions: Dosage of biochar at m (C)/m(Cr) = 3.0, reaction temperature of 90 °C, reaction [...] Read more.

A highly efficient reduction process of Cr (VI) with biochar was conducted in this paper. The results showed that nearly 100% Cr (VI) was reduced at selected reaction conditions: Dosage of biochar at m (C)/m(Cr) = 3.0, reaction temperature of 90 °C, reaction time of60 min, and concentration of H₂SO₄ of 20 g/L. The reduction kinetics analysis demonstrated that the reduction of Cr (VI) fitted well with the pseudo-first-order model and the apparent activation energy was calculated to be 40.24 kJ/mol. Response surface methodology confirmed that all of the experimental parameters had a positive effect on the reduction of Cr (VI). The influence of each parameter on the reduction process followed the order: Dosage of biochar>concentration of H₂SO₄>reaction temperature >reaction time. This paper provides a versatile strategy for the treatment of wastewater containing Cr (VI) and shows a bright tomorrow for wastewater treatment. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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14 pages, 4913 KiB

Open AccessArticle

A Novel Rotary Dryer Filled with Alumina Ceramic Beads for the Treatment of Industrial Wastewaters: Numerical Simulation and Experimental Study

by Lixin Xie, Lingling Yang, Libo Su, Shichang Xu and Wen Zhang

Processes 2021, 9(5), 862; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9050862 - 13 May 2021

Cited by 4 | Viewed by 4120

Abstract

In this study, a new type of rotary dryer filled with inert alumina ceramic bead (ACB) fillers was introduced to treat the industrial wastewater, e.g., the high-salt wastewater and landfill leachate. Numerical simulations based on the Discrete Element Method (DEM) on the motion [...] Read more.

In this study, a new type of rotary dryer filled with inert alumina ceramic bead (ACB) fillers was introduced to treat the industrial wastewater, e.g., the high-salt wastewater and landfill leachate. Numerical simulations based on the Discrete Element Method (DEM) on the motion trajectory of ACB fillers in the rotary dryer were conducted, and the parameters of flight structure, rotational speed, and filling degree on the dynamic behavior of ACB fillers were optimized. Under various rotational speeds and filling degrees, the experimental results fit the numerical-simulated results very well. The optimized flight configuration was the straight flights with a length of 65 mm, and the optimized rotational speed and filling degree were 35 rpm and 15%, respectively. Under the optimized condition, both the response variables, the mass of particles in the airborne phase (MAP) and the percentage of occupied area in the airborne region (OAR), have the optimal values, in which the dryer will have a better drying performance. Besides, the lower-right area of the drum is empty which is convenient for the installation of the inlet pipe. The drying experiments of industrial wastewaters were also studied using this ACB filled rotary drum dryer under the optimized conditions. Under the optimal operational conditions, the evaporation capacities of the high-salt wastewater and landfill leachate could reach as high as 49.7 kg/h and 90 kg/h, respectively. This study highlights the integration of evaporation and drying processes of this novel ACB filled rotary dryer and provides an efficient and zero-liquid-emission strategy for the thermal treatment of industrial wastewater. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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Review

Jump to: Research

19 pages, 1890 KiB

Open AccessFeature PaperEditor’s ChoiceReview

A Review of Stand-Alone and Hybrid Microbial Electrochemical Systems for Antibiotics Removal from Wastewater

by Basem S. Zakaria and Bipro Ranjan Dhar

Processes 2022, 10(4), 714; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10040714 - 07 Apr 2022

Cited by 4 | Viewed by 3739

Abstract

The growing concern about residual antibiotics in the water environment pushes for innovative and cost-effective technologies for antibiotics removal from wastewater. In this context, various microbial electrochemical systems have been investigated as an alternative to conventional wastewater technologies that are usually ineffective for [...] Read more.

The growing concern about residual antibiotics in the water environment pushes for innovative and cost-effective technologies for antibiotics removal from wastewater. In this context, various microbial electrochemical systems have been investigated as an alternative to conventional wastewater technologies that are usually ineffective for the adequate removal of antibiotics. This review article details the development of stand-alone and hybrid or integrated microbial electrochemical systems for antibiotics removal from wastewater. First, technical features, antibiotics removal efficiencies, process optimization, and technological bottlenecks of these systems are discussed. Second, a comparative summary based on the existing reports was established to provide insights into the selection between stand-alone and hybrid systems. Finally, research gaps, the relevance of recent progress in complementary areas, and future research needs have been discussed. Full article

(This article belongs to the Special Issue Emerging Technologies for Water and Wastewater Treatment)

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