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A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Wastewater Treatment and Reuse".

Deadline for manuscript submissions: closed (20 December 2024) | Viewed by 22296

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Special Issue Editors

Prof. Dr. Yung-Tse Hung

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Guest Editor

Department of Civil and Environmental Engineering, Cleveland State University, Cleveland, OH 44115, USA
Interests: water supply and water treatment; municipal wastewater treatment; industrial waste treatment; biological waste treatment; water and wastewater treatment plant design; water pollution control; water quality engineering
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Tsuyoshi Imai

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Guest Editor

Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-16-1 Tokiwadai, Ube 755-8611, Japan
Interests: biological wastewater treatment (aerobic, anaerobic); biological treatment/recycling of organic solid waste; oxygen supply methods in aerobic wastewater treatment; CO₂ removal and storage
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Prof. Dr. Rehab O. Abdel Rahman

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Guest Editor

Hot Laboratories and Waste Management Center, Atomic Energy Authority, Inshas, Cairo 13759, Egypt
Interests: water and wastewater treatment; pollution control; radioactive wastes; mathemat-ical modeling; nanomaterials; cement-based materials; hazardous waste immobili-zation
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Issam A. Al-Khatib

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Guest Editor

Institute of Environmental and Water Studies, Faculty of Graduate Studies, Birzeit University, Birzeit P.O. Box 14, Palestine
Interests: water recourses management and quality; environmental assessment; wastewater management; advocacy; coordination and networking
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Special Issue Information

Dear Colleagues,

Water treatment and wastewater treatment are very important to protect public health, environmental health, and the global economy. These treatment processes will protect safe as well as reliable water resources and may help in promoting sustainable development. Biological treatment technologies have been in existence for many years for water and wastewater treatment, and are closely related to treatment performance efficiency, construction and operation costs, energy requirements, operational flexibility, and environmental impacts.

Recently, biotechnology has been explored for the improvement of water treatment and wastewater treatment processes. The challenge will be to couple treatment efficiency with sustainable development to remove contaminants in water as well as wastewater, produce renewable energy, and meet the ever-increasingly stringent standards of regulatory agencies.

The aim of this Special Issue of Water is to present the latest reports related to the applications of current biotechnology processes to enhance and improve the treatment performance of water as well as wastewater treatment processes and reduce the costs of treatment with potential energy recovery. Authors are encouraged to present their original research and review papers in related areas.

Prof. Dr. Yung-Tse Hung
Prof. Dr. Tsuyoshi Imai
Prof. Dr. Rehab O. Abdel Rahman
Prof. Dr. Issam A. Al-Khatib
Guest Editors

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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. Water is an international peer-reviewed open access semimonthly 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 2600 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

biotechnologies for water treatment
biotechnologies for wastewater treatment
advanced water treatment
advanced wastewater treatment
nutrient recovery from wastewater
energy recovery from wastewater
emerging contaminants in water and wastewater treatment
industrial waste treatment
municipal wastewater treatment
water reuse
water treatment

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Related Special Issue

Advanced Biotechnologies for Water and Wastewater Treatment, 2nd Edition in Water (2 articles)

Published Papers (12 papers)

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Editorial

Jump to: Research

4 pages, 148 KiB

Open AccessEditorial

Advanced Biotechnologies for Water and Wastewater Treatment

by Yung-Tse Hung, Rehab O. Abdel Rahman, Issam A. Al-Khatib and Tsuyoshi Imai

Water 2025, 17(4), 509; https://doi.org/10.3390/w17040509 - 11 Feb 2025

Cited by 1 | Viewed by 1067

Abstract

The use of biotechnology to control and prevent the contamination of water resources has a long track record that goes back to the beginning of the 20th century [...] Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

Research

Jump to: Editorial

25 pages, 4510 KiB

Open AccessArticle

Effect of Calcination Temperature on the Photocatalytic Activity of Precipitated ZnO Nanoparticles for the Degradation of Rhodamine B Under Different Light Sources

by Amira Saidani, Reguia Boudraa, Karim Fendi, Lamia Benouadah, Abderrahim Benabbas, Atmane Djermoune, Stefano Salvestrini, Jean-Claude Bollinger, Abdulmajeed Abdullah Alayyaf and Lotfi Mouni

Water 2025, 17(1), 32; https://doi.org/10.3390/w17010032 - 26 Dec 2024

Cited by 2 | Viewed by 1423

Abstract

This research provides valuable insights into the application of ZnO nanoparticles in photocatalytic wastewater treatment. Process optimization was carried out by determining the ratio of the surface area to the energy band gap (S/E) in the photocatalysis rate under different sources of light (UV light, visible light, sunlight). The nanoparticles were synthesized using the precipitation technique, and the calcination process was carried out within a temperature range of 400 to 700 °C. The structural, morphological, and optical properties of materials were investigated using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance (UV-Vis DRS), Raman spectroscopies, and Fourier transform infrared (FTIR) spectroscopies. The study demonstrates that calcination temperature significantly influences the photocatalytic activity of ZnO nanoparticles by altering their size, surface properties, shape, and optical behavior. Optimal decomposition efficiencies of Rhodamine B were achieved at 400 °C, with yields of 24%, 92%, and 91% under visible, UV, and sunlight irradiation, respectively. Additionally, the surface area decreased from 12.556 to 8.445 m²/g, the band gap narrowed slightly from 3.153 to 3.125 eV, and crystal growth increased from 0.223 to 0.506 µm as the calcination temperature rose. The photocatalytic properties of ZnO nanoparticles were assessed to determine their efficiency in decomposing Rhodamine B dye under operational parameters, including pollutant concentration (C0), sample amount, pH level, and reaction time. The sample exhibited the best breakdown rates with C0 = 5 mg/L, solid-to-liquid ratio (S/L) = 50 mg/L, pH = 7, and reaction time = 1 h. Additionally, we combined two oxidation processes, namely H₂O₂ and photocatalytic oxidation processes, which significantly improved the Rhodamine B removal efficiency, where 100% of RhB was degraded after 60 min and 100 µL of H₂O₂. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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26 pages, 4845 KiB

Open AccessArticle

The Pyrolysis of Biosolids in a Novel Closed Coupled Pyrolysis and Gasification Technology: Pilot Plant Trials, Aspen Plus Modelling, and a Techno-Economic Analysis

by Nimesha Rathnayake, Savankumar Patel, Ibrahim Gbolahan Hakeem, Ganesh Veluswamy, Ibrahim Al-Waili, Shivani Agnihotri, Arun Krishna Vuppaladadiyam, Aravind Surapaneni, David Bergmann and Kalpit Shah

Water 2024, 16(23), 3399; https://doi.org/10.3390/w16233399 - 26 Nov 2024

Viewed by 1808

Abstract

Pyrolysis is gaining recognition as a sustainable solution for biosolid management, though scaling it commercially presents challenges. To address this, RMIT developed a novel integrated pyrolysis and gasification technology called PYROCO™, which was successfully tested in pilot-scale trials. This study introduces PYROCO™ and its application to produce biochar, highlighting the biochar properties of the results of the initial trials. In addition, an energy analysis using semi-empirical Aspen Plus modelling, paired with a preliminary techno-economic assessment, was carried out to evaluate the feasibility of this technology. The results show that the PYROCO™ pilot plant produced biochar with a ~30 wt% yield, featuring beneficial agronomic properties such as high organic carbon (210–220 g/kg) and nutrient contents (total P: 36–42 g/kg and total N: 16–18 g/kg). The system also effectively removed contaminants such as PFASs, PAHs, pharmaceuticals, and microplastics from the biochar and scrubber water and stack gas emissions. An energy analysis and Aspen Plus modelling showed that a commercial-scale PYROCO™ plant could operate energy self-sufficiently with biosolids containing >30% solids and with a minimum calorific value of 11 MJ/kg. The process generates excess energy for drying biosolids and for electricity generation. Profitability is sensitive to biochar price; prices rise from AUD 300 to AUD 1000 per tonne, the NPV improves from AUD 0.24 million to AUD 4.31 million, and the payback period shortens from 26 to 12 years. The low NPV and high payback period reflect the use of a relatively high discount rate of 8%, chosen to be on the conservative side given the novel nature of the technology. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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16 pages, 4654 KiB

Open AccessArticle

Designing, Modeling and Developing Scale Models for the Treatment of Water Contaminated with Cr (VI) through Bacterial Cellulose Biomass

by Uriel Fernando Carreño Sayago, Vladimir Ballesteros Ballesteros and Angelica Maria Lozano Aguilar

Water 2024, 16(17), 2524; https://doi.org/10.3390/w16172524 - 5 Sep 2024

Cited by 3 | Viewed by 1232

Abstract

The present research presents a method for scaling up a continuous treatment system with bacterial cellulose biomass for the removal of contaminants on a large industrial scale from effluents loaded with chromium (VI). This consisted of a laboratory-scale modeling process of the chromium (VI) adsorption processes, which would provide the necessary parameters to build a system on an industrial scale. The research also involved designing, modeling and developing scale models for the treatment of water contaminated with chromium (VI) through bacterial cellulose biomass. The results of the model indicated the specific route for the construction of a treatment system on an industrial scale, with the experimental data adjusted to achieve this objective. The pilot scale prototype was built using 450 g of biomass, including elution processes, with the data obtained from the aforementioned processes. In general, the excellent efficiency of the two models at different scales, together with the excellent elution results, suggests that this prototype could be presented to polluting industries for the treatment of water from different industrial effluents, being an advanced biotechnology for the treatment of industrial wastewater. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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16 pages, 2989 KiB

Open AccessArticle

Microbial Selection for the Densification of Activated Sludge Treating Variable and High-Strength Industrial Wastewater

by Mukhtiar Ahmed, Dorothee Goettert, Catharina Vanherck, Koen Goossens and Jan Dries

Water 2024, 16(15), 2087; https://doi.org/10.3390/w16152087 - 24 Jul 2024

Viewed by 1828

Abstract

This study investigates the densification/granulation of activated sludge with poor settleability, treating real industrial wastewater from a tank truck cleaning company. The wastewater is low in nutrients, acidic in nature, and high and variable in chemical oxygen demand (COD, ranging from 2770 mg·L⁻¹ to 14,050 mg·L⁻¹). A microbial selection strategy was applied to promote slow-growing glycogen-accumulating microorganisms (GAO) by the implementation of an anaerobic feast/aerobic famine strategy in a sequencing batch reactor (SBR). After 60 to 70 days, the uptake of carbon during the anaerobic phase exceeded 80%, the sludge morphology improved, and the sludge volume index (SVI) dropped below 50 mL·g⁻¹. 16S rRNA gene sequencing showed the enrichment of the GAOs Defluviicoccus and Candidatus Competibacter. Stable sludge densification was maintained when using a constant organic loading rate (OLR) of 0.85 ± 0.05 gCOD·(L·d)⁻¹, but the sludge quality deteriorated when switching to a variable OLR. In view of the integration of densified/granular sludge in a membrane bioreactor configuration, the filtration properties of the densified SBR sludge were compared to the seed sludge from the full-scale plant. The densified sludge showed a significantly lower resistance due to pore blockage and a significantly higher sustainable flux (45 vs. 15 L·(m²·h)⁻¹). Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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13 pages, 2800 KiB

Open AccessArticle

Construction of Genetically Engineered Escherichia coli Cell Factory for Enhanced Cadmium Bioaccumulation in Wastewater

by Lingna Tian, Daiwei Wang, Yueying Liu, Mingjie Wei, Xuexue Han, Xiaomei Sun, Liang Yin and Guanghong Luo

Water 2024, 16(13), 1759; https://doi.org/10.3390/w16131759 - 21 Jun 2024

Cited by 4 | Viewed by 2309

Abstract

The heavy metal cadmium poses severe threats to both ecosystems and human health. Utilizing genetic engineering to enhance the microbial capability for efficient cadmium accumulation has emerged as a pivotal research direction. This study constructed a genetically engineered bacterium capable of expressing multivalent phytochelatins with a self-assembly ability and explored its efficacy in cadmium adsorption. Molecular biology techniques were adopted to fuse the recombinant human ferritin (rHF) gene and the synthetic phytochelatin (EC) gene, known for its robust adsorption capacity for heavy metals. The expression vector was constructed. Escherichia coli (E. coli) served as the host cell to express multivalent nanochelator rHF-ECs tailored for high-efficiency heavy metal adsorption. The results reveal the successful soluble expression of the recombinant fusion protein in E. coli cells, forming self-assembled multivalent nanoparticles with a size of about 13 nm, and the target protein rHF-EC20 (monomer) could adsorb approximately 9.2 μmol of Cd²⁺ in vitro. Moreover, this recombinant strain demonstrated cadmium adsorption across a temperature range of 16–45 °C and a pH range of 5–9, with the optimal performance observed at pH 7.0 and 37 °C. Compared with the control strain, the recombinant strain BL21 (FLE), expressing nano-chelating peptides, achieves an adsorption rate of 80% for Cd²⁺ at 60 min, resulting in an approximately 18% increase in the Cd²⁺ enrichment efficiency. The maximum adsorption capability of cadmium reached 12.62 mg per gram of dry cell weight. This work indicated that the synthesis of multivalent chelating peptides in E. coli cells could efficiently enhance the bioaccumulation of the heavy metal cadmium, which renders novel avenues and methodologies for addressing cadmium pollution, offering promising prospects for environmental remediation. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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13 pages, 3274 KiB

Open AccessArticle

The Design of a Process for Adsorbing and Eluting Chromium (VI) Using Fixed-Bed Columns of E. crassipes with Sodium Tripolyphosphate (TPP)

by Uriel Fernando Carreño Sayago and Vladimir Alfonso Ballesteros Ballesteros

Water 2024, 16(7), 952; https://doi.org/10.3390/w16070952 - 26 Mar 2024

Cited by 4 | Viewed by 1539

Abstract

Proper water resource management is a critical global objective, both privately and in business, due to the continuous deterioration of this valuable resource. Scientific research in environmental sciences has made significant progress in the development and achievements of treatment. The use of transformed E. crassipes biomass with sodium tripolyphosphate (TPP) can help to achieve this important goal. The objective of this study was to develop an experimental process for the continuous adsorption and elution of chromium (VI) using fixed-bed columns of E. crassipes biomass modified with sodium tripolyphosphate (TPP). Additionally, design tools were created, and economic viability was assessed by analyzing adsorption capacity indicators and unit production costs of different biomasses. Treatment systems were designed and constructed to remove chromium from tannery wastewater, ensuring that the levels were below the current environmental regulations of 0.05 mg/L Cr(VI). The biomass had an adsorption capacity of 98 mg/g and was produced at a low cost of 8.5 dollars. This resulted in an indicator of 11.5 g Cr(VI)/(USD) when combined with the elution processes. The proposed strategy, which utilizes entirely green technologies, enables the recovery and valorization of water resources. This makes it an effective tool for the circular economy. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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13 pages, 7368 KiB

Open AccessEditor’s ChoiceArticle

Immobilization of Horseradish Peroxidase and Myoglobin Using Sodium Alginate for Treating Organic Pollutants

by Xinyu Wang, Hossein Ghanizadeh, Shoaib Khan, Xiaodan Wu, Haowei Li, Samreen Sadiq, Jiayin Liu, Huimin Liu and Qunfeng Yue

Water 2024, 16(6), 848; https://doi.org/10.3390/w16060848 - 15 Mar 2024

Cited by 9 | Viewed by 2161

Abstract

Removing organic pollutants from wastewater is crucial to prevent environmental contamination and protect human health. Immobilized enzymes are increasingly being explored for wastewater treatment due to their specific catalytic activities, reusability, and stability under various environmental conditions. Peroxidases, such as horseradish peroxidase (HRP) and myoglobin (Mb), are promising candidates for immobilized enzymes utilized in wastewater treatment due to their ability to facilitate the oxidation process of a wide range of organic molecules. However, the properties of the carrier and support materials greatly influence the stability and activity of immobilized HRP and Mb. In this research, we developed immobilized HRP and Mb using support material composed of sodium alginate and CaCl₂ as carriers and glutaraldehyde as a crosslinking agent. Following this, the efficacy of immobilized HRP and Mb in removing aniline, phenol, and p-nitrophenol was assessed. Both immobilized enzymes removed all three organic pollutants from an aqueous solution, but Mb was more effective than HRP. After being immobilized, both enzymes became more resilient to changes in temperature and pH. Both immobilized enzymes retained their ability to eliminate organic pollutants through eight treatment cycles. Our study uncovered novel immobilized enzyme microspheres and demonstrated their successful application in wastewater treatment, paving the way for future research. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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12 pages, 1509 KiB

Open AccessArticle

Xenobiotic Removal by Trametes hirsuta LE-BIN 072 Activated Carbon-Based Mycelial Pellets: Remazol Brilliant Blue R Case Study

by Olga. A. Glazunova, Konstantin V. Moiseenko and Tatyana V. Fedorova

Water 2024, 16(1), 133; https://doi.org/10.3390/w16010133 - 29 Dec 2023

Cited by 3 | Viewed by 1654

Abstract

As a toxic xenobiotic compound, the anthraquinone dye Remazol Brilliant Blue R (RBBR) poses a serious threat to aquatic ecosystems. In the present study, the ability of Trametes hirsuta to remove RBBR from the medium was investigated, and the role of adsorption by fungal mycelium and biodegradation by fungal enzymes was evaluated. It was shown that the whole fungal culture was able to remove up to 97% of the dye within the first four hours of incubation. Based on enzymatic activities in the culture broth, laccases were proposed to be the main enzymes contributing to RBBR degradation, and RT-qPCR measurements demonstrated an increase in transcription for the two laccase genes—lacA and lacB. Composite mycelial pellets of T. hirsuta with improved adsorption ability were prepared by adding activated carbon to the growth medium, and the induction of laccase activity by carbon was shown. For composite pellets, the RBBR decolorization degree was about 1.9 times higher at 1 h of incubation compared to carbon-free pellets. Hence, it was shown that using fungal mycelium pellets containing activated carbon can be an effective and economical method of dye removal. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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18 pages, 4633 KiB

Open AccessArticle

Degradation of Phenol by Immobilized Alcaligenes faecalis Strain JH1 in Fe₃O₄-Modified Biochar from Pharmaceutical Residues

by Zhi Zeng, Jiahui Xiao, Manzhi Li, Jiahui Wu and Taiping Zhang

Water 2023, 15(23), 4084; https://doi.org/10.3390/w15234084 - 24 Nov 2023

Cited by 6 | Viewed by 1744

Abstract

The effect and mechanism of phenol removal by immobilized microorganisms in Fe₃O₄ nanomaterial-modified pharmaceutical residue biochar was investigated to develop efficient biochar immobilizing microbial technology. Plant residue biochar (Y3, Y5, and Y7) was prepared from Andrographis paniculata plant residues as the raw material at 300 °C, 500 °C, and 700 °C, respectively. Y7 was modified with Fe₃O₄ nanomaterial (Fe-Y7). These four kinds of biochars were used as carriers to adsorb immobilized Alcaligenes faecalis strain JH1, JY3, JY5, JY7, and Fe-Y7 to investigate the mechanism of phenol removal, and eight cycles were performed to analyze their immobilization performance. Compared with suspended bacteria, biochar-immobilized bacteria could improve their tolerance in different environments. At temperatures of 25 °C to 40 °C, pH = 5~9, initial phenol concentration of 300–500 mg/L, and salinity of 3%, the bacteria could still grow and maintain strong activity within 48 h. The water-extractable organic carbon of biochar was also tested for the degradation of phenol by bacteria, which was found to have different stimulating effects on bacteria. In the batch experiments, as the number of cycles increased, the bacteria grew and adhered rapidly to the biochar, eventually forming a thick and sticky biofilm. After the sixth cycle, all the biochar-immobilized bacteria could remove 300 mg/L phenol solution within 12 h. The removal rate of phenol by JFe-Y7 was relatively fast in the eighth cycle. The results indicated that biochar-immobilized bacteria have good durability, stability, and reproducibility and that Fe₃O₄ nanoparticle modification could improve the removal of phenol by increasing the phenol adsorption amount, the adsorption capacity of bacteria, and the enzymatic activity of bacteria. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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12 pages, 4051 KiB

Open AccessArticle

Over-Produced Extracellular Polymeric Substances and Activated Antioxidant Enzymes Attribute to Resistance of Pb(II) for Algal–Bacterial Granular Sludge in Municipal Wastewater Treatment

by Juanru Yang, Yu Zhang and Shulian Wang

Water 2023, 15(21), 3833; https://doi.org/10.3390/w15213833 - 2 Nov 2023

Cited by 1 | Viewed by 1731

Abstract

Algal–bacterial granular sludge technology is a new type of wastewater treatment and resource regeneration process, which has received widespread attention due to its excellent nitrogen and phosphorus removal performance, and energy-saving and emission reduction effects. Although algal–bacterial granular sludge technology has achieved an ideal nutrient removal ability, some pol-lutants in wastewater might affect the symbiotic relationship between algae and bacteria. This study investigated the impact of coexisting Pb(II) on the symbiosis of algal–bacterial granular sludge. It was found that 2.5–10.0 mg/L of Pb(II) exposure increased the relative abundance of Pro-teobacteria. In addition, more protein in extracellular polymeric substances (EPS-PN) was secreted at 2.5 mg/L of Pb(II) exposure while EPS-PN content reduced at a rate of 5.0–10.0 mg/L of Pb(II). Under different concentrations of Pb(II), the damage degree of algal–bacterial granular sludge was exacerbated, evidenced by increased malondialdehyde (MDA) content. To cope with these adverse circumstances, the antioxidant enzyme activity of both super-oxide dismutase (SOD) and peroxidase dismutase (CAT) was boosted. With the help of these adaptive strategies, the symbiosis of algal–bacterial granular sludge was stable. Moreover, the performance of algal–bacterial granular sludge in treating COD, ammonia-N and phosphate-P was kept at above 95%. This study approved that a Pb(II) concentration less than 10.0 mg/L had little effect on the performance of algal–bacterial granular sludge in wastewater treatment. It is hoped that this study can provide useful information for an improved engineering feasibility of algal–bacterial granular sludge process. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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15 pages, 3959 KiB

Open AccessArticle

Adaptive Neuro-Fuzzy Inference System Modeling and Optimization of Microbial Fuel Cells for Wastewater Treatment

by Mohammad Ali Abdelkareem, Samah Ibrahim Alshathri, Mohd Shahbudin Masdar and Abdul Ghani Olabi

Water 2023, 15(20), 3564; https://doi.org/10.3390/w15203564 - 12 Oct 2023

Cited by 4 | Viewed by 2291

Abstract

Due to their toxicity, Cr(VI) levels are subject to strict legislation and regulations in various industries and environmental contexts. Effective treatment technologies are also being developed to decrease the negative impacts on human health and the environment by removing Cr(VI) from water sources and wastewater. As a result, it would be interesting to model and optimize the Cr(VI) removal processes, especially those under neutral pH circumstances. Microbial fuel cells (MFCs) have the capacity to remove Cr(VI), but additional research is needed to enhance their usability, increase their efficacy, and address issues like scalability and maintaining stable operation. In this research work, ANFIS modeling and artificial ecosystem optimization (AEO) were used to maximize Cr(VI) removal efficiency and the power density of MFC. First, based on measured data, an ANFIS model is developed to simulate the MFC performance in terms of the Cu(II)/Cr(VI) ratio, substrate (sodium acetate) concentration (g/L), and external resistance Ω. Then, using artificial ecosystem optimization (AEO), the optimal values of these operating parameters, i.e., Cu(II)/Cr(VI) ratio, substrate concentration, and external resistance, are identified, corresponding to maximum Cr(VI) removal efficiency and power density. In the ANFIS modeling stage of power density, the coefficient-of-determination is enhanced to 0.9981 compared with 0.992 (by ANOVA), and the RMSE is decreased to 0.4863 compared with 16.486 (by ANOVA). This shows that the modeling phase was effective. In sum, the integration between ANFIS and AEO increased the power density and Cr(VI) removal efficiency by 19.14% and 15.14%, respectively, compared to the measured data. Full article

(This article belongs to the Special Issue Advanced Biotechnologies for Water and Wastewater Treatment)

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