Advances in Water and Wastewater Treatment Processes

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: closed (15 March 2023) | Viewed by 35547

Special Issue Editors


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Guest Editor
Laboratory of Environmental Engineering & Management, School of Chemical and Environmental Engineering, Technical University of Crete, Chania, Greece
Interests: water engineering; ecological engineering; nature-based solutions; wastewater treatment and management; constructed wetlands; circular economy; sustainability
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Guest Editor
1. UCD School of Civil Engineering, University College Dublin, Belfield, Dublin, Ireland
2. Institute of Water Resources & Hydro-electric Engineering, Xi'an University of Technology, Xi’an 710048, China
Interests: unconventional water and wastewater treatment technology; new constructed wetland technology; microbial fuel cell; ecological engineering; ecological restoration of surface water (rivers, lakes, bays, etc.); waterworks sludge regulation; dehydration and beneficial reuse
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Chemistry, University of Beira Interior, 6201-001 Covilhã, Portugal
Interests: water quality; wastewater treatment; chemistry; water analysis; adsorption; ozonation; antioxidant activity; chemical oxidation; membrane technology

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Guest Editor
Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, 15773 Athens, Greece
Interests: wastewater treatment; biological nutrient removal; activated sludge; membrane bioreactors; industrial wastewater; nature-based solutions
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Special Issue Information

Dear Colleagues,

Although the science of water and wastewater engineering is old, it is a field with continuous development and innovation. Established technologies are optimized in terms of performance, environmental footprint, energy demand, and area requirements, while new and alternative technological solutions are today available. The world of water and wastewater engineering offers today many diverse tools applicable to different economic, climatic, and social contexts. Therefore, it is important to further understand and increase our knowledge on the status and developments of the various wastewater treatment technologies and processes. This Special Issue will cover the most recent progress and developments in the wide range of the treatment technologies to provide the state-of-the-art knowledge for the removal of pollutant from water and wastewater.

Contributions are accepted from both research and the industry as well as experiences from full-scale applications and case studies. Review papers summarizing the existing knowledge and technological status of different technologies and processes are also welcome. The potential technologies include but are not limited to:

  • Activated sludge and its variants
  • Extended aeration
  • Membrane filtration and bioreactors
  • Sequencing batch reactors
  • Attached growth biofilm reactors
  • Moving bed biofilm reactors
  • Aerobic / anaerobic systems
  • Nature-based solutions such as constructed wetlands, stabilization ponds, etc.
  • Trickling filters
  • Upflow anaerobic sludge blanket reactors
  • Chemical treatment
  • Microbial fuel cells
  • Filtration with eg activated carbon, natural rocks, synthetic media, etc.
  • Dissolved air flotation
  • Coagulation, flocculation, adsorption, ion exchange
  • Advanced oxidation processes such as ozonation, photocatalysis, UV radiation, hydrogen peroxide oxidation, etc.
  • Waste sludge minimization and stabilization
  • Materials and nutrient recovery
  • Mathematical simulation methods

Dr. Alexandros Stefanakis
Prof. Dr. Yaqian Zhao
Dr. Arlindo Gomes
Dr. Simos Malamis
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • water and wastewater treatment
  • treatment technologies
  • water purification
  • industrial wastewater
  • municipal wastewater

Published Papers (10 papers)

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Research

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16 pages, 3369 KiB  
Article
Assessment of Heavy Metal Pollution in Water Sediment and Study on Pollution Mechanism—Taking the Weihe River Basin in China as an Example
by Yuxia Xu, Xin Liao and Bei Guo
Processes 2023, 11(2), 416; https://doi.org/10.3390/pr11020416 - 30 Jan 2023
Cited by 3 | Viewed by 2404
Abstract
To ensure the ecological security of the basin, data on the heavy metal content in the sediments of the Weihe River Basin were collected to analyze the spatial distribution characteristics of heavy metals based on descriptive statistics and geostatistics. The geoaccumulation index and [...] Read more.
To ensure the ecological security of the basin, data on the heavy metal content in the sediments of the Weihe River Basin were collected to analyze the spatial distribution characteristics of heavy metals based on descriptive statistics and geostatistics. The geoaccumulation index and potential ecological risk assessment were conducted, and the number of pollution sources and the contribution rate were determined by combining correlation analysis, principal component analysis, and APCS-MLR. The results showed that the mean values of As, Pb, Zn, Ni, Cr, Hg, Cu, and Cd were 15.42, 27.27, 88.05, 31.05, 75, 0.13, 29.47, and 1.05 mg·kg−1, respectively. Igeo is in the order of Cd > Hg > As > Cu > Pb > Zn > Cr > Ni. Cd had the highest potential ecological risk factor, followed by Hg with a critical risk proportion of 12.6%. The traceability analysis showed that the heavy metals come from mixed, industrial, and agricultural sources, among which Pb, Zn, Ni, Cr, and Cu are affected by soil-forming parent materials and industrial comprehensive sources, As is affected by agricultural sources, and Hg and Cd are affected by industrial sources. Industrial and living sources are the main sources of the heavy metals. The results of the study can provide a basis for formulating relevant pollution prevention and control measures in the Weihe River Basin. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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20 pages, 9235 KiB  
Article
Performance Comparison of EGSB and IC Reactors for Treating High-Salt Fatty Acid Organic Production Wastewater
by Qinfang Lu, Byung-gon Jeong, Shirong Lai, Zehua Yan, Xin Xiao and Wei Jiang
Processes 2022, 10(7), 1295; https://doi.org/10.3390/pr10071295 - 30 Jun 2022
Cited by 3 | Viewed by 1947
Abstract
This study used the EGSB and IC reactors to treat the high-salt and high-concentration organic wastewater (high-salt fatty acid production wastewater) and compared their performances The experimental results showed that the optimal influent water quality thresholds for both bioreactors to treat this wastewater [...] Read more.
This study used the EGSB and IC reactors to treat the high-salt and high-concentration organic wastewater (high-salt fatty acid production wastewater) and compared their performances The experimental results showed that the optimal influent water quality thresholds for both bioreactors to treat this wastewater were a COD concentration of 18,000 mg/L and a sulfate ion concentration of about 8000 mg/L. The reactor operated well when C/S was greater than 2.8. In addition, the value of C/S should not be less than 1.5. This is due to that under this condition, the sulfate reduction process has a significant impact on the removal of COD, and MPB may be inhibited by sulfides. The organic load OLR should not be greater than 10 kgCOD/(m3·d). It was also found that the start-up time of the IC reactor with external circulation was slightly shorter, and the COD removal effect, gas production rate, and load tolerance were slightly better than those of the EGSB reactor, the best reflux ratio of the two reactors was 6:1. The appropriate rising flow rate was 0.4 m/h. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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15 pages, 4504 KiB  
Article
Precipitation Behavior of Salts in Supercritical Water: Experiments and Molecular Dynamics Simulations
by Yafei Song, Zhe Li, Qiao Zhu, Zibin Huang and Zhenmin Cheng
Processes 2022, 10(2), 423; https://doi.org/10.3390/pr10020423 - 21 Feb 2022
Cited by 5 | Viewed by 2564
Abstract
Supercritical water desalination (SCWD) shows great potential in the treatment of high-salt wastewater with zero liquid discharge. To investigate the salt precipitation behavior and mechanism in supercritical water, experiments and molecular dynamics simulations (MDs) were used to study the salting-out process of different [...] Read more.
Supercritical water desalination (SCWD) shows great potential in the treatment of high-salt wastewater with zero liquid discharge. To investigate the salt precipitation behavior and mechanism in supercritical water, experiments and molecular dynamics simulations (MDs) were used to study the salting-out process of different salts in supercritical water. The equilibrium concentrations of NaCl, KCl, CaCl2, Na2SO4, and Na2CO3 in supercritical water were experimentally measured. When the temperature exceeded 693 K, the salt equilibrium concentration measured in the experiment was less than 130 mg/L. The solubility decreased in the order of KCl > NaCl > CaCl2 > Na2SO4 > Na2CO3. To elucidate the effects of different cations and anions in supercritical water on salt dissolution and precipitation behavior, the potential energy, radial distribution function (RDF) and coordination number in the system were obtained via molecular dynamics simulation. Experimental and MD results showed that salt solubility has significant positive correlation with systemic potential energy and hydration number. MD results indicated that a small ionic radius, large ionic charge, and low hydration coordination number are favorable for inorganic salts to precipitate and crystallize since these factors can strengthen the interaction between free ions and salt clusters. Moreover, due to the formation of multilayer coordination structure, polyatomic ions can achieve a lower equilibrium concentration than that of the corresponding monatomic ions. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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12 pages, 3272 KiB  
Article
A Study on the Hydrolysis of Urea Contained in Wastewater and Continuous Recovery of Ammonia by an Enzymatic Membrane Reactor
by Mukhtar Nuhu Yahya, Hüseyin Gökçekuş, Derin Orhon, Bülent Keskinler, Ahmet Karagunduz and Philip Isaac Omwene
Processes 2021, 9(10), 1703; https://doi.org/10.3390/pr9101703 - 23 Sep 2021
Cited by 9 | Viewed by 4390
Abstract
1. Background: Urea is the main product of the nitrogenous breakdown of protein metabolism in mammals. In this study, process intensification for enzymatic hydrolysis of urea by urease enzyme (jack bean urease) was examined in a membrane reactor. 2. Methods: Batch and continuous [...] Read more.
1. Background: Urea is the main product of the nitrogenous breakdown of protein metabolism in mammals. In this study, process intensification for enzymatic hydrolysis of urea by urease enzyme (jack bean urease) was examined in a membrane reactor. 2. Methods: Batch and continuous enzymatic hydrolysis reactions were performed at different substrate concentrations to determine the digestibility and affinity of the substrate with that of the enzyme. The hydrolysate samples were obtained by an optimized continuous enzyme membrane reactor (EMR) coupled with an ultra-filtration membrane (250 kDa). Feed concentration varied from 100 to 500 mg/L. Laboratory experiments were conducted at room temperature (20 ± 1 °C), with a flow rate of 20 mL/min, urease concentration of 0.067 g/L, ionic strength (I = 0, 0.01, 0.05), and ammonium nitrogen addition of (0, 100 mg/L, 200 mg/L, 500 mg/L). Moreover, the effect of ionic strength, ammonium nitrogen concentration, feed concentration, and enzyme concentration on urea hydrolysis was examined. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX) analysis were used to identify the physicochemical properties as well as the elemental composition of the Ultra-Filtration membrane used in this study. 3. Results: The study revealed that higher ionic strength and higher concentrations of NH4SO2 and ammonium nitrogen (NH3-N) inhibithydrolysis of urea by reducing the urease enzyme activity in the system over time. 4. Conclusions: Herein, a sustainable alternative for the conversion of urea to ammonia by utilizing urease in an EMR was demonstrated. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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12 pages, 2917 KiB  
Article
The Effect of Initial Conditions with Aerobic Biological Treatment on Aniline Dyeing Wastewater
by Huancheng Dong, Hongmei Liu, Xue Yang, Houjie Gong, Heng Zhang, Runkai Wang, Lili Yan and Wenning Mai
Processes 2021, 9(8), 1329; https://doi.org/10.3390/pr9081329 - 30 Jul 2021
Cited by 5 | Viewed by 2353
Abstract
According to the characteristics of aniline dyeing wastewater, aerobic biological treatment was adopted herein, and high-throughput sequencing technology was used to analyze the changes to the microbial community structure and diversity in the aerobic sludge acclimation stage. As a result, according to the [...] Read more.
According to the characteristics of aniline dyeing wastewater, aerobic biological treatment was adopted herein, and high-throughput sequencing technology was used to analyze the changes to the microbial community structure and diversity in the aerobic sludge acclimation stage. As a result, according to the experimental study on the effects of different biomass, the initial pH value and the salinity with the aerobic biological treatment, the chemical oxygen demand (COD) degradation rate can increase linearly with the increase in biomass under different biomass conditions. The organic matter degradation rate is 6.24 mg/L COD·h−1·(mg/L·MLSS)−1, with a correlation coefficient (R2) of 0.98704. When the initial pH value is less than 7.0 ± 0.2, the COD degradation rate increases with the increase in the initial pH value and then decreases gradually. The optimal sludge concentration is 4 g/L; the optimal initial pH value is in the range of 7.0–8.0; the optimal salinity is 1.7%. When the initial concentration of COD is 3000 mg/L, the COD value gradually stabilizes and decreases to 1500 mg/L after 32 h, the degradation rate reaches 50%, and the pH decreases from 7.5 to 4.5. Sphingopyxis has been detected in sludge samples from the third cycle of acclimation, which can biodegrade aromatic compounds, anthraquinone dyes, and their intermediates, and the relative abundance of Sphingopyxis increased from 0.18% to 5.08%, indicating a potential biodegradation ability of aniline dyeing wastewater. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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12 pages, 1384 KiB  
Article
Intensification of a Neutralization Process for Waste Generated from Ion Exchange Regeneration for Expansion of a Chemical Manufacturing Facility
by Deepak Sharma, Avinashkumar V. Karre, Kalliat T. Valsaraj and Sumit Sharma
Processes 2021, 9(8), 1285; https://doi.org/10.3390/pr9081285 - 25 Jul 2021
Viewed by 3112
Abstract
Waste generated during regeneration of Ion Exchanger (IX), used for deionizing water, needs to be neutralized before it can be discharged back to a clean water source. An efficient and novel process is disclosed that minimizes the neutralization volume and chemicals required for [...] Read more.
Waste generated during regeneration of Ion Exchanger (IX), used for deionizing water, needs to be neutralized before it can be discharged back to a clean water source. An efficient and novel process is disclosed that minimizes the neutralization volume and chemicals required for pH adjustment. The currently employed neutralization setups in the industry are environmentally unsustainable. Various neutralization setups were studied for treating waste generated from IX regeneration. From the collected plant data, the treatment requirements of waste streams generated during regeneration of IX beds were analyzed. An efficient neutralization setup was developed to lower the operating and capital costs by eliminating the need of some equipment and by lowering the neutralization volume. The new process results in considerable savings compared to currently used processes in the industry and is environmentally benign. The improved neutralization setup proposed in this work has achieved a 63% reduction in volume of IX regeneration waste stream; a 62% reduction in the capital cost; 23% reduction in chemical usage; and a 55% reduction in operating cost. The achieved improvements are quite significant, which are bound to immensely benefit the chemical industries that require demineralized water for their operation. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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11 pages, 2563 KiB  
Article
Study on the Removal of Fluorescent Whitening Agent from Paper-Mill Wastewater Using the Submerged Membrane Bioreactor (SMBR) with Ozone Oxidation Process
by Seunghan Ryu, Sanghun Lee, Hannah Oh, Sanghwa Oh, Minsoo Park, Jinho Kim and Jaeeun Heo
Processes 2021, 9(6), 1068; https://doi.org/10.3390/pr9061068 - 18 Jun 2021
Viewed by 2009
Abstract
In this study, paper-mill wastewater was treated using the Submerged Membrane Bioreactor (SMBR) process. In particular, the ozone oxidation treatment process is applied after SMBR to remove the fluorescent whitening agent, which is a trace pollutant and non-biodegradable. Fluorescent whitening agent concentration was [...] Read more.
In this study, paper-mill wastewater was treated using the Submerged Membrane Bioreactor (SMBR) process. In particular, the ozone oxidation treatment process is applied after SMBR to remove the fluorescent whitening agent, which is a trace pollutant and non-biodegradable. Fluorescent whitening agent concentration was indirectly measured by UV scanning and COD concentration. The concentration of COD before SMBR and ozone oxidation was 449.3 mg/L, and the concentration of treated water was 100.3 mg/ℓ. The COD removal efficiency of paper-mill wastewater through SMBR and the ozone oxidation process was about 77.68%. The optimized amount of ozone was required for the removal of the fluorescent whitening agent after SMBR was 95 mg·O3/ℓ calculated by UV scan results. Additionally, the optimized amount of required ozone to remove COD was calculated to 0.126 mg·COD/mg·O3. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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13 pages, 1698 KiB  
Article
The Tolerance of Anoxic-Oxic (A/O) Process for the Changing of Refractory Organics in Electroplating Wastewater: Performance, Optimization and Microbial Characteristics
by Jingsi Gao, Chongsen Duan, Xiao Huang, Jianghua Yu, Zhen Cao and Jia Zhu
Processes 2021, 9(6), 962; https://doi.org/10.3390/pr9060962 - 28 May 2021
Cited by 5 | Viewed by 2882
Abstract
In order to investigate the tolerance of an anoxic-oxic (A/O) process for the changing of refractory organics in electroplating wastewater, optimize the technological parameters, and reveal the microbial characteristics, a pilot-scale A/O process was carried out and the microbial community composition was analyzed [...] Read more.
In order to investigate the tolerance of an anoxic-oxic (A/O) process for the changing of refractory organics in electroplating wastewater, optimize the technological parameters, and reveal the microbial characteristics, a pilot-scale A/O process was carried out and the microbial community composition was analyzed by high-throughput sequencing. The results indicated that a better tolerance was achieved for sodium dodecyl benzene sulfonate, and the removal efficiencies of organic matter, ammonia nitrogen (NH4+-N), and total nitrogen (TN) were 82.87%, 66.47%, and 53.28% with the optimum hydraulic retention time (HRT), internal circulation and dissolved oxygen (DO) was 12 h, 200% and 2–3 mg/L, respectively. Additionally, high-throughput sequencing results demonstrated that Proteobacteria and Bacteroidetes were the dominant bacteria phylum, and the diversity of the microbial community in the stable-state period was richer than that in the start-up period. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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Review

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11 pages, 17459 KiB  
Review
Challenges of Urban Artificial Landscape Water Bodies: Treatment Techniques and Restoration Strategies towards Ecosystem Services Enhancement
by Olivia Addo-Bankas, Yaqian Zhao, Arlindo Gomes and Alexandros Stefanakis
Processes 2022, 10(12), 2486; https://doi.org/10.3390/pr10122486 - 23 Nov 2022
Cited by 5 | Viewed by 2801
Abstract
With the rapid adoption of green infrastructure and nature-based solutions for a low-impact development, much consideration is given to ecosystem services and the ecological enhancement in modern planning of urban spaces. Artificial landscape water bodies have, in recent years, been utilized to enhance [...] Read more.
With the rapid adoption of green infrastructure and nature-based solutions for a low-impact development, much consideration is given to ecosystem services and the ecological enhancement in modern planning of urban spaces. Artificial landscape water bodies have, in recent years, been utilized to enhance the ecological quality of urban environments. As an environmentally friendly measure, the water source of these waters has predominantly been adopting reclaimed water (treated wastewater). As a result, landscape water bodies are often eutrophic, exhibiting poor hydrodynamics, with lengthy water change cycles, creating the ideal environment for algal blooms that negatively impact the aesthetic appeal of these landscape waters. Based on the existing literature, this paper summarizes the treatment techniques and strategies employed in enhancing the quality of urban artificial landscape water bodies and providing integrated design solutions in the urban environment. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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12 pages, 3245 KiB  
Review
Application of Alum Sludge in Wastewater Treatment Processes: “Science” of Reuse and Reclamation Pathways
by Wei Zhao, Huina Xie, Jie Li, Lihong Zhang and Yaqian Zhao
Processes 2021, 9(4), 612; https://doi.org/10.3390/pr9040612 - 31 Mar 2021
Cited by 26 | Viewed by 8603
Abstract
Alum sludge (AlS) refers to the inevitable by-product generated during the drinking water purification process, where Al-salt is used as a coagulant in the water industry. It has long been treated as “waste”, while landfill is its major final disposal destination. In fact, [...] Read more.
Alum sludge (AlS) refers to the inevitable by-product generated during the drinking water purification process, where Al-salt is used as a coagulant in the water industry. It has long been treated as “waste”, while landfill is its major final disposal destination. In fact, AlS is an underutilized material with huge potential for beneficial reuse as a raw material in various wastewater treatment processes. In the last two decades, intensive studies have been conducted worldwide to explore the “science” and practical application of AlS. This paper focuses on the recent developments in the use of AlS that show its strong potential for reuse in wastewater treatment processes. In particular, the review covers the key “science” of the nature and mechanisms of AlS, revealing why AlS has the potential to be a value-added material. In addition, the future focus of research towards the widespread application of AlS as a raw material/product in commercial markets is suggested, which expands the scope for AlS research and development. Full article
(This article belongs to the Special Issue Advances in Water and Wastewater Treatment Processes)
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