Municipal Wastewater Treatment and Removal of Micropollutants

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

Deadline for manuscript submissions: 30 April 2025 | Viewed by 12590

Special Issue Editors


E-Mail Website
Guest Editor
Department of Environmental Engineering, Institute of Chemical and Environmental Engineering, Slovak University of Technology, Bratislava 81237, Slovakia
Interests: ozone based advanced oxidation processes; biological and combined treatment processes; municipal, industrial wastewater and landfill leachate treatment; minimizing of sludge production, micropollutants, emerging pollutants, priority, hazardous and persistent substances; degradation, transformation and biodegradability enhancement; processes modelling and design

E-Mail Website
Guest Editor
Department of Chemical Engineering and Technical Safety, Facuty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
Interests: treatment of industrial and municipal wastewater; sustainable solid waste management; microplastics

E-Mail Website
Guest Editor
Water Research Institute, Slovak National Water Reference Laboratory, Department of Basic and Inorganic Chemistry, Nábr. arm. gen. L. Svobodu 5, 812 49 Bratislava, Slovakia
Interests: biological treatment; chemical analysis; environment protection; macronutrients; micropollutants; organics; physical-chemical processes; toxicity; wastewater

Special Issue Information

Dear Colleagues,

We would like to take this opportunity to invite you to participate in this Special Issue on "(Municipal) Wastewater Treatment and Micropollutant Removal Processes" to be published in the open access journal Processes (ISSN 2227-9717; indexed in SCIE and Scopus; IF = 3.5 and CiteScore = 4.7, ranking Q2 in the category "Engineering, Chemical")), an international peer-reviewed open access journal on processes in chemistry, biochemistry, biology, materials, and related process/systems engineering research areas.

The removal of macronutrients and micropollutants is one of the most pressing problems of municipal wastewater treatment. Both categories of pollutants are characterized by their seriousness in terms of the protection of human health and the protection of the environment. A common feature is also a large amount of treated wastewater. However, they differ in the variety of pollutants and their concentration values. These specifics are reflected in the applied processes and treatment technologies. The dominant ones include biological processes and their combination with other processes. With extensive applications and significant progress in technological practice, effective procedures and technologies have been developed for the removal of macronutrient N and P from municipal wastewater. The main challenges for their further development include intensification and reduction in material and energy inputs.

The diversity of micropollutants from the point of view of the spectrum of pollutants, their structure, properties, and negative effects has initiated many separation, transformation, and degradation processes. The greatest attention is paid to priority, persistent, and toxic substances. However, in technological practice, degradation, separation, and combined processes are expanding, which make it possible to eliminate numerous micropollutants, or their toxic and harmful effects.

An important link between the removal of macronutrient and micropollutants is sewage and excess sludge, on which a significant amount of micropollutants is adsorbed. Their elimination from sludge increases the potential for their safe use in agriculture. At the same time, sludge degradation can serve as a renewable source of organic carbon for biological processes of macronutrient removal.

Prof. Dr. Jan Derco
Prof. Dr. Andreja Žgajnar Gotvajn
Dr. Angelika Kassai
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

  • biological treatment
  • micropollutants
  • minimization of material and energy inputs
  • priority and persistent substances
  • reduction in sludge production
  • degradative
  • transformation, separation, and combined processes
  • sludge treatment
  • toxicity
  • renewable carbon source
  • processes’ and technologies’ sustainability
  • wastewater treatment
  • water reuse

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (9 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

15 pages, 3259 KiB  
Article
Reconstruction of the Municipal Wastewater-Treatment Plant According to the Principles of Aerobic Granular Sludge Cultivation
by Miroslav Hutňan, Barbora Jankovičová, Lenka Jajcaiová, Mikhael Sammarah, Karol Kratochvíl and Nikola Šoltýsová
Processes 2024, 12(9), 1782; https://doi.org/10.3390/pr12091782 - 23 Aug 2024
Viewed by 929
Abstract
The work presents the concept of aerobic granular sludge (AGS) and its potential for wastewater treatment. The work also evaluates the condition of the SBR (Sequencing Batch Reactor) type of municipal wastewater-treatment plant (WWTP) after its reconstruction into a system with AGS. The [...] Read more.
The work presents the concept of aerobic granular sludge (AGS) and its potential for wastewater treatment. The work also evaluates the condition of the SBR (Sequencing Batch Reactor) type of municipal wastewater-treatment plant (WWTP) after its reconstruction into a system with AGS. The WWTP parameters achieved before and after reconstruction were compared. Operational measurements of the process during the individual phases of the treatment process showed a balanced concentration profile of the monitored parameters in the span of the semicontinuous cycle. Laboratory tests showed that the sludge from the WWTP has nitrification and denitrification rates comparable to the rates achieved for flocculent sludge, and it is also comparable to the nitrification and denitrification rates of AGS with size of granules below 400 µm. Despite the fact that complete sludge granulation was not achieved, the results measured at the WWTP confirmed the advantages of the AGS concept. Neither anaerobic nor anoxic conditions were identified in the SBR during the individual phases of operation, yet high removal efficiencies of ammonia and nitrate nitrogen and orthophosphate phosphorus were achieved. The concentration of ammonia and nitrate nitrogen at the WWTP effluent was below 5 mg/L, and the concentration of phosphorus was below 0.5 mg/L. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

25 pages, 9093 KiB  
Article
Highly Adsorptive Organic Xerogels for Efficient Removal of Metformin from Aqueous Solutions: Experimental and Theoretical Approach
by S. A. Aguilar-Maruri, D. Perera-Triana, Elizabeth Flórez, Angélica Forgionny, Gabriela Palestino, C. F. A. Gómez-Durán and Raúl Ocampo-Pérez
Processes 2024, 12(7), 1431; https://doi.org/10.3390/pr12071431 - 9 Jul 2024
Viewed by 1000
Abstract
Metformin, widely prescribed to treat type 2 diabetes for its effectiveness and low cost, has raised concerns about its presence in aqueous effluents and its potential environmental and public health impacts. To address this issue, xerogels were synthesized from resorcinol and formaldehyde, with [...] Read more.
Metformin, widely prescribed to treat type 2 diabetes for its effectiveness and low cost, has raised concerns about its presence in aqueous effluents and its potential environmental and public health impacts. To address this issue, xerogels were synthesized from resorcinol and formaldehyde, with molar ratios ranging from 0.05 to 0.40. These xerogels were thoroughly characterized using FT-IR, SEM, TGA, and TEM analyses. Batch adsorption experiments were performed with standard metformin solutions at concentrations of 50 and 500 mg/L, varying pH, and temperature to determine the adsorption isotherms of the synthesized xerogels. The adsorption data revealed a maximum adsorption capacity of 325 mg/g at pH 11 and 25 °C. Quantum chemical calculations revealed that electrostatic interactions govern metformin adsorption onto xerogels. The xerogels’ adsorption capacity was evaluated in competitive systems with CaCl2, NaCl, MgCl2, and synthetic urines. Reuse cycles demonstrated that xerogels could be reused for up to three cycles without any loss in adsorptive efficiency. The adsorption mechanisms of metformin in the adsorption process highlight the strong electrostatic interactions and hydrogen bonds between the adsorbate and the adsorbent material. Xerogels synthesized show promise as efficient adsorbents to remove metformin from aqueous solutions, helping to mitigate its environmental impact. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

15 pages, 1827 KiB  
Article
Impact of Combined Electrolysis and Activated Sludge Process on Municipal Wastewater Treatment
by Miroslav Hutňan, Barbora Jankovičová, Ronald Zakhar and Nikola Šoltýsová
Processes 2024, 12(5), 868; https://doi.org/10.3390/pr12050868 - 25 Apr 2024
Viewed by 1226
Abstract
Electrochemical methods for the treatment of municipal and industrial wastewater are used either independently or in conjunction with biological methods for pretreatment or posttreatment of biologically treated wastewater. In our work, the combination of these processes was studied, where pre-electrolysis was used to [...] Read more.
Electrochemical methods for the treatment of municipal and industrial wastewater are used either independently or in conjunction with biological methods for pretreatment or posttreatment of biologically treated wastewater. In our work, the combination of these processes was studied, where pre-electrolysis was used to produce dissolved iron before the activation process. Electrolysis was also directly introduced into the activation using either iron or carbon electrodes. The surface of one iron electrode was 32.2 cm2, voltage at the electrodes was 21 V, and current was 270 mA. The surface of one carbon electrode was 7.54 cm2, current was 82.5 mA, and voltage at the electrodes was 21 V. Laboratory research on synthetic municipal wastewater treatment using a combination of electrolysis and activation processes showed that the use of iron electrodes increases the efficiency of phosphorus removal compared to its precipitation with iron salts. Electrolysis has shown a positive effect on the sedimentation properties of sludge and the destruction of filamentous microorganisms. Even though it negatively affected the respiration rates of activated sludge and the denitrification efficiency, it did not have a negative impact on the nitrification activity of sludge. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Graphical abstract

16 pages, 1692 KiB  
Article
Ciprofloxacin Uptake from an Aqueous Solution via Adsorption with K2CO3-Activated Biochar Derived from Brewing Industry Bagasse
by Víctor Francisco Meseguer, Juan Francisco Ortuño, María Isabel Aguilar, Mercedes Lloréns, Ana Belén Pérez-Marín and Emmanuel Fuentes
Processes 2024, 12(1), 199; https://doi.org/10.3390/pr12010199 - 17 Jan 2024
Cited by 2 | Viewed by 1391
Abstract
Ciprofloxacin (CPX), an antibiotic considered as an emerging contaminant, needs to be removed from aquatic environments. This work investigates the adsorption of CPX on K2CO3-activated biochar (AB). The biochar was obtained via the pyrolysis of barley bagasse from the [...] Read more.
Ciprofloxacin (CPX), an antibiotic considered as an emerging contaminant, needs to be removed from aquatic environments. This work investigates the adsorption of CPX on K2CO3-activated biochar (AB). The biochar was obtained via the pyrolysis of barley bagasse from the brewing industry, and then it was activated with 2M of K2CO3. The activated biochar was characterised using FTIR spectroscopy and a pHPZC assay. Batch adsorption tests were performed to study the influence of pH and temperature on CPX sorption and to obtain kinetic and equilibrium data. The adsorption of CPX on AB was favoured by increasing the temperature from 10 °C to 55 °C, demonstrating the endothermic nature of the process. The level of CPX removal after 24 h of contact and at pH 3.5 was 82% of that obtained when equilibrium was reached. The kinetic study showed that the adsorption is well described by the Elovich and the Bangham kinetic models. The adsorption is favourable, and the best fits to the experimental equilibrium data were obtained with the Freundlich, Redlich–Peterson and Sips isotherms. In an acidic solution (pH = 3.5) and at 25 °C, the maximum CPX adsorption capacity of AB was ≈105 mg·g−1, comparable to that reported for other adsorbents. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

13 pages, 4258 KiB  
Article
Optimization of Binary Adsorption of Metronidazole and Sulfamethoxazole in Aqueous Solution Supported with DFT Calculations
by Juan Carlos Serna-Carrizales, Ana I. Zárate-Guzmán, Angélica Aguilar-Aguilar, Angélica Forgionny, Esther Bailón-García, Elizabeth Flórez, Cesar F. A. Gómez-Durán and Raúl Ocampo-Pérez
Processes 2023, 11(4), 1009; https://doi.org/10.3390/pr11041009 - 27 Mar 2023
Cited by 6 | Viewed by 1833
Abstract
Sulfamethoxazole [SMX] and metronidazole [MNZ] are emergent pollutants commonly found in surface water and wastewater, which can cause public health and environmental issues even at trace levels. An efficient alternative for their removal is the application of adsorption technology. The present work evaluated [...] Read more.
Sulfamethoxazole [SMX] and metronidazole [MNZ] are emergent pollutants commonly found in surface water and wastewater, which can cause public health and environmental issues even at trace levels. An efficient alternative for their removal is the application of adsorption technology. The present work evaluated single and binary adsorption processes using granular activated carbon (CAG F400) for SMX and MNZ in an aqueous solution. The binary adsorption process was studied using a Box–Behnken experimental design (RSD), and the results were statistically tested using an analysis of variance. Density functional theory (DFT) modeling was employed to characterize the interactions between the antibiotics and the CAG F400 surface. For the individual adsorption process, adsorption capacities (qe) of 1.61 mmol g−1 for SMX and 1.10 mmol g−1 for MNZ were obtained. The adsorption isotherm model that best fit experimental data was the Radke–Prausnitz isotherm model. The adsorption mechanism occurs through electrostatic and π-π dispersive interactions. For the binary adsorption process, the total binary adsorption capacity achieved was 1.13 mmol g−1, evidencing competitive adsorption. The significant factors that determine the removal of SMX and MNZ from a binary solution were the solution pH and the initial concentration of antibiotics. From DFT studies, it was found that SMX adsorption on CAG F400 was favored with adsorption energy (Eads) of −10.36 kcal mol−1. Finally, the binary adsorption results corroborated that the adsorption process was favorable for both molecules. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

Review

Jump to: Research

30 pages, 1400 KiB  
Review
Cardiovascular Drugs as Water Contaminants and Analytical Challenges in the Evaluation of Their Degradation
by Aleksander Kravos, Andreja Žgajnar Gotvajn and Helena Prosen
Processes 2024, 12(10), 2177; https://doi.org/10.3390/pr12102177 - 7 Oct 2024
Viewed by 650
Abstract
Cardiovascular drugs have been a burning topic in the field of environmental analytical chemistry in the last few decades. Growing modern healthcare has led to the widespread use of pharmaceuticals. Among these, antihypertensives (sartans, angiotensin-converting enzyme inhibitors) and lipid-regulating drugs (fibrates and statins) [...] Read more.
Cardiovascular drugs have been a burning topic in the field of environmental analytical chemistry in the last few decades. Growing modern healthcare has led to the widespread use of pharmaceuticals. Among these, antihypertensives (sartans, angiotensin-converting enzyme inhibitors) and lipid-regulating drugs (fibrates and statins) are the most frequently consumed and, thus, excreted into wastewater. Their chemical fate during conventional and advanced wastewater treatment, such as ozonation, remains unclear. Analytical chemistry, providing sample pretreatment followed by instrumental analysis, has a tremendous role in water treatment evaluation, mostly from the perspective of parent contaminants’ removals and also assessment of transformation pathways. Ultrasensitive liquid chromatography–mass spectrometry (LC-MS) systems provide many opportunities. By carefully using planned workflows for chromatographic and mass-spectrometric data processing, i.e., suspect and non-target screening approaches, LC-MS allows for the identification and structural elucidation of unknown, predicted, suspected or selected transformation products. Accordingly, some examples and case studies on selected cardiovascular drugs in this review are presented to show the applicability of the used analytical approaches and workflows. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

22 pages, 10121 KiB  
Review
Recent Advances in the Photocatalytic Degradation of Phenol over Bi-Based Oxide Catalysts
by Zhangpei Liu, Maosheng Qian, Xiaomeng Cheng and Zhiming Liu
Processes 2024, 12(9), 1799; https://doi.org/10.3390/pr12091799 - 24 Aug 2024
Viewed by 642
Abstract
Wastewater containing phenolic organic compounds, such as phenol, produced during industrial manufacturing processes, poses a significant threat to aquatic ecosystems and crops. Photocatalytic technology is considered the most promising approach to water treatment due to its efficiency and eco-friendly advantages. Compared to other [...] Read more.
Wastewater containing phenolic organic compounds, such as phenol, produced during industrial manufacturing processes, poses a significant threat to aquatic ecosystems and crops. Photocatalytic technology is considered the most promising approach to water treatment due to its efficiency and eco-friendly advantages. Compared to other photocatalysts, Bi-based oxides are more efficient due to their unique layered structure, which allows for photocatalytic reactions to occur between layers. This review introduces the synthesis methods of various bismuth-based multi-element oxides and their efficiency in the photocatalytic decomposition of phenol. The effects of elemental doping, defect introduction, and heterojunction construction on the catalytic performance and structure of Bi-based oxides are discussed. The mechanisms for the photocatalytic degradation of phenol over different materials are also summarized and discussed. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

42 pages, 3854 KiB  
Review
Nutrient Removal and Recovery from Municipal Wastewater
by Ján Derco, Andreja Žgajnar Gotvajn, Patrícia Guľašová, Angelika Kassai and Nikola Šoltýsová
Processes 2024, 12(5), 894; https://doi.org/10.3390/pr12050894 - 28 Apr 2024
Viewed by 1543
Abstract
With the ongoing amendment of the EU legislation on the treatment of urban wastewater, stricter requirements for the removal of pollutants are expected, which calls for the need for innovative wastewater treatment technologies. Biological systems are still the first choice. A survey of [...] Read more.
With the ongoing amendment of the EU legislation on the treatment of urban wastewater, stricter requirements for the removal of pollutants are expected, which calls for the need for innovative wastewater treatment technologies. Biological systems are still the first choice. A survey of typical bioreactors applied in wastewater treatment is presented. The wastewater treatment objective, biochemical environment, and microbial growth are selected as the main criteria for the classification of these bioreactors. Hydraulic and kinetic aspects are considered, along with the advantages and drawbacks of these bioreactors regarding the selection of the appropriate type of reactor; as well, details regarding the operation of reactors are mentioned. The aim of this paper is to provide operators and designers with a brief overview of the selected traditional and advanced processes, reactors, and technologies for nutrient removal from municipal wastewater. The possibilities and limitations in complying with more strict effluent standards are also discussed. Methods of nutrient recovery are added value. From the evaluation of the published papers, we determine that the currently applied traditional methods for nutrient removal have the potential to also convey the expected stricter limits. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

23 pages, 619 KiB  
Review
An Extensive Analysis of the Engineering Design of Underground Sewage Plants in China
by Abdulmoseen Segun Giwa and Nasir Ali
Processes 2023, 11(10), 3010; https://doi.org/10.3390/pr11103010 - 19 Oct 2023
Cited by 3 | Viewed by 2472
Abstract
In recent years, underground sewage treatment plants that can remarkably reduce land occupation with less environmental pollution are gradually entering the popular consciousness and are now being used widely. However, problems associated with the traditional treatment plants, such as high construction and operation [...] Read more.
In recent years, underground sewage treatment plants that can remarkably reduce land occupation with less environmental pollution are gradually entering the popular consciousness and are now being used widely. However, problems associated with the traditional treatment plants, such as high construction and operation cost, severe health and safety risks, and monotonous landscape design have limited their value and restricted their application and promotion. Through the literature and field investigations, the value of underground sewage treatment plants (STPs) was analyzed, their engineering and landscape design were studied, and their development direction was explored in order to supply a theoretical basis for further application and development of underground STPs. The analysis showed that as a new model of environmentally friendly sewage treatment and resource conservation, underground STPs have the apparent advantages of lower cost of land use for construction and pipeline as well as an outstanding value for the urban landscape and ecological environment. These factors can offset its relatively high construction and operating costs to a certain extent, especially when compared with above-ground STPs. The engineering design study results showed that significant differences existed between underground STPs and traditional above-ground STPs, and that the main contents of the engineering design of underground STPs consist of treatment scale and degree, influent and effluent qualities, site selection, design model, underground arrangement and structure, main treatment process, monomer structure, ventilation and deodorization, daylighting and artificial lightings, fire safety, operation and maintenance, and the linkage design between the above-ground landscape and the underground STP. Full article
(This article belongs to the Special Issue Municipal Wastewater Treatment and Removal of Micropollutants)
Show Figures

Figure 1

Back to TopTop