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Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse
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Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse

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

Deadline for manuscript submissions: closed (15 November 2022) | Viewed by 34048

Special Issue Editors

Dr. Weihua Zhao

E-Mail Website
Guest Editor
1. Department of Environmental and Civil Engineering, Qingdao University of Technology, Qingdao 266033, China
2. Harbin Institute of Technology (Weihai), Weihai 264209, China
Interests: biological nitrogen and phosphorus removal; resources recovery and energy neutralization; water environment protection and water ecological restoration; rural wastewater treatment; sludge treatment
Special Issues, Collections and Topics in MDPI journals
Dr. Kai Wang

E-Mail Website
Guest Editor
Department of Environmental and Civil Engineering, Shandong Jianzhu University, Jinan 250000, China
Interests: biological nitrogen and phosphorus removal; rural wastewater treatment
Dr. Shanyun Wang

E-Mail Website
Guest Editor
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
Interests: microbial nitrogen cycle process and nitrogen pollution control in aquatic ecosystem; anammox; comammo); DNRA

Special Issue Information

Dear Colleagues,

Organic and nutrient removal from wastewater plays an important role in water environment and ecological protection. Meanwhile, conventional biological wastewater treatment processes consume a lot of energy, carbon sources and chemicals and produce greenhouse gases. It is of great significance to realize “carbon neutralization” in wastewater treatment, and resource recovery, energy neutralization and water reuse will be the goal of wastewater treatment in the future. Relevant research has developed rapidly in recent years, such as anaerobic ammonia oxidation, denitrifying phosphorus removal, shortcut nitrification, partial denitrification and endogenous denitrification; phosphorus recovery in the form of blue iron ore and guano crystallization; energy saving through precise aeration and process control; organic and energy recovery by sludge fermentation, anaerobic methane production and sewage heat source pumps; water reclaimed by advanced oxidation, adsorption and membrane filtration; and carbon capture and storage through symbiosis of bacteria, algae, etc. These new processes and technologies accelerate the realization of “carbon neutralization” in the field of wastewater treatment.

In order to trace the research progress of “carbon neutralization” in wastewater treatment, a Special Issue has been organized by Water. This Special Issue focuses on original articles or review articles related to “carbon neutralization” in wastewater treatment, including, but not limited to, the following:

  • Deep nitrogen and phosphorus removal from wastewater;
  • Recovery of resources and nutrients from wastewater;
  • Energy saving and recovery from wastewater treatment;
  • Directional conversion and recovery of organic matter, nitrogen and phosphorus in sludge;
  • Transformation and removal of new pollutants and refractory components;
  • Reclaimed water reuse;
  • Carbon capture and storage from wastewater treatment;
  • Other related topics.

Dr. Weihua Zhao
Dr. Kai Wang
Dr. Shanyun Wang
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. 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

  • carbon neutralization
  • anammox
  • denitrifying phosphorus removal
  • shortcut nitrification
  • partial denitrification
  • process control
  • sludge fermentation
  • advanced oxidation
  • adsorption
  • membrane filtration

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Published Papers (13 papers)

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Research

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14 pages, 3150 KiB  
Article
Study on the Mechanism and Control Strategy of Advanced Treatment of Yeast Wastewater by Ozone Catalytic Oxidation
by Xianglong Jing, Shikun Cheng, Cong Men, Huimin Zhu, Mei Luo and Zifu Li
Water 2023, 15(2), 274; https://doi.org/10.3390/w15020274 - 09 Jan 2023
Viewed by 1808
Abstract
In this paper, the yeast wastewater secondary treatment effluent using catalytic odor oxidation treatment, using an orthogonal reaction experiment to determine the best reaction conditions, and the online monitoring of the pH, oxidation-reduction potential (ORP), and liquid ozone concentration monitoring, to the catalytic [...] Read more.
In this paper, the yeast wastewater secondary treatment effluent using catalytic odor oxidation treatment, using an orthogonal reaction experiment to determine the best reaction conditions, and the online monitoring of the pH, oxidation-reduction potential (ORP), and liquid ozone concentration monitoring, to the catalytic odor oxidation reaction, chemical oxygen demand (COD), and color removal effect were analyzed. The results showed that the optimal reaction condition for the advanced treatment of yeast wastewater by catalytic ozonation was accomplished with manganese dioxide used as the catalyst and a catalyst dose of 6 g·L−1, pH of 12, and catalytic ozonation reaction time of 20 min. The COD was effectively reduced from 880 mg·L−1 to 387 mg·L−1 under this condition, the chroma was reduced from 700 times to 40 times, and these two parameters of the effluent could meet the standard of GB25462-2010. The real-time monitoring system showed that the whole reaction can be divided into two processes. The first 14 min was the indirect reaction of ozone and then the direct oxidation reaction of ozone. This process was further verified by the change trend of COD and the amount of ozone depletion by COD removal. The average ozone consumption levels of the two stages were 1.97 and 4.91 mgO3·mgCOD−1. This system can effectively monitor the reaction of the catalytic odor oxidation in the complex system to guide the effective use of ozone in practical engineering applications. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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15 pages, 3814 KiB  
Article
Preparation of Magnetic Dummy Molecularly Imprinted Meso-Porous Silica Nanoparticles Using a Semi-Covalent Imprinting Approach for the Rapid and Selective Removal of Bisphenols from Environmental Water Samples
by Jing Chen, Xiaoli Sun, Muhua Wang, Yan Wang, Qinyao Wu, Shurong Wu and Sisi Fang
Water 2022, 14(24), 4125; https://doi.org/10.3390/w14244125 - 18 Dec 2022
Viewed by 1691
Abstract
Bisphenol compounds (BPs) are a severe threat to humans and creatures; hence it is critical to develop a quick and simple approach for removing trace BPs from water. This research synthesized a novel template–monomer complex, phenolphthalein-(3-isocyanatopropyl)triethoxysilane (PP-ICPTES), as a dummy template, and a [...] Read more.
Bisphenol compounds (BPs) are a severe threat to humans and creatures; hence it is critical to develop a quick and simple approach for removing trace BPs from water. This research synthesized a novel template–monomer complex, phenolphthalein-(3-isocyanatopropyl)triethoxysilane (PP-ICPTES), as a dummy template, and a molecularly imprinted polymer for bisphenol was made via a semi-covalent approach. By successfully coating the imprinted layer on the Fe3O4@SiO2@mSiO2 structure, a magnetic dummy molecularly imprinted mesoporous silica nanoparticles (m-DMI-MSNPs) with a core-shell structure and superefficient aqueous phase selectivity for bisphenols was synthesized. The morphology and structure of the m-DMI-MSNPs were characterized using transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis, Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM). The prepared m-DMI-MSNPs presented excellent water compatibility and magnetic separation abilities. The m-DMI-MSNPs showed excellent recognition selectivity towards BPs with imprinting factors of 7.6, 8.2, and 7.5 for bisphenol F (BPF), bisphenol E (BPE), and bisphenol A (BPA), respectively. Fast binding kinetics (equilibrium time < 1 min) and a high rebinding capacity (maximum adsorption capacity, 38.75 mg g–1) were observed in the adsorption experiments. More importantly, the m-DMI-MSNPs, which combine good water compatibility, class selectivity, and magnetic separation performance, exhibited excellent performance for the removal of BPF, BPE, and BPA from tap water, mineral water, and sewage water samples, with removal efficiencies in the ranges of 96.6–97.8, 95.6–97.1, and 93.1–95.3%, respectively. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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16 pages, 4983 KiB  
Article
Enhanced Swine Wastewater Treatment by Constructed Wetland—Microbial Fuel Cell Systems
by Yun Zhang, Feng Liu, Yidong Lin, Lei Sun, Xinru Guo, Shuai Yang and Jinlong He
Water 2022, 14(23), 3930; https://doi.org/10.3390/w14233930 - 02 Dec 2022
Cited by 4 | Viewed by 1401
Abstract
This paper studies the effects of planting plants and coupled microbial fuel cells (MFCs) on the decontamination capacity and purification mechanism of constructed wetlands (CWs). Four systems were set, namely CW-without plants (A1), CW-with plants (A2), CW-MFC-without plants (A3) and CW-MFC-with plants (A4). [...] Read more.
This paper studies the effects of planting plants and coupled microbial fuel cells (MFCs) on the decontamination capacity and purification mechanism of constructed wetlands (CWs). Four systems were set, namely CW-without plants (A1), CW-with plants (A2), CW-MFC-without plants (A3) and CW-MFC-with plants (A4). The daily reductions per unit area of chemical oxygen demand (COD) were 48.72 ± 5.42, 51.26 ± 4.10, 53.49 ± 5.44 and 58.54 ± 4.16 g·(d·m2)−1, respectively. The daily reductions per unit area of nitrogen (N) were 11.89 ± 0.73, 12.38 ± 0.76, 12.24 ± 0.79 and 13.61 ± 1.07 g·(d·m2)−1, respectively. After studying the pollutant removal efficiency, it was found that the unit area of A4 removes the highest number of pollutants, improving the area efficiency of the wetland system and fundamentally alleviating the disadvantage of the large land footprint of wetland processes. The average output voltages of A3 and A4 were 568.29 and 717.46 mV, respectively, and the maximum power densities were 4.59 and 15.87 mW/m3, respectively. In addition, after high-throughput analysis of microbial samples, anaerobic ammonia oxidising (anammox) bacteria were found to remove N from the system in the anaerobic anode region. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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17 pages, 4404 KiB  
Article
Degradation of Methylene Blue in the Photo-Fenton-Like Process with WO3-Loaded Porous Carbon Nitride Nanosheet Catalyst
by Weifan Gao, Guichang Zhang, Xiaoping Zhang, Shaoqi Zhou and Zihao Wang
Water 2022, 14(16), 2569; https://doi.org/10.3390/w14162569 - 20 Aug 2022
Cited by 2 | Viewed by 2033
Abstract
The catalytic capability of original carbon nitride (CN) is limited by a small specific surface area and high electron–hole recombination rate. In this study, WO3-loaded porous carbon nanosheets (MCA-CN/WO3) were synthesized by thermal treatment with melamine, cyanuric acid and [...] Read more.
The catalytic capability of original carbon nitride (CN) is limited by a small specific surface area and high electron–hole recombination rate. In this study, WO3-loaded porous carbon nanosheets (MCA-CN/WO3) were synthesized by thermal treatment with melamine, cyanuric acid and WCl6. The MCA-CN/WO3 could degrade 98% of the methylene blue (MB) within 30 min in the photo-Fenton-like process, displaying better catalytic activity than the original CN (30%), pure MCA-CN (63%) and original CN/WO3 (87%). The results of photoluminescence and electrochemical impedance spectroscopy demonstrated that the Z-scheme heterojunction of MCA-CN/WO3 inhibited the recombination of electrons and holes. In addition, the porous nanosheet structure accelerated the electron transfer and provided abundant active sites for MB degradation. A radical quenching experiment indicated that the Z-scheme heterojunction facilitated the decomposition of H2O2 to produce 1O2 for MB degradation. The possible degradation pathways of MB were proposed. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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13 pages, 3951 KiB  
Article
Effective Removal of Humic Acid by Zr-MOFs with Surface Modification
by Yuankang Jiang, Zhenggang Wang, Zhiping Zhu, Mingpeng He and Pan Zhou
Water 2022, 14(11), 1800; https://doi.org/10.3390/w14111800 - 02 Jun 2022
Cited by 3 | Viewed by 2074
Abstract
Humic acid (HA) in makeup water is one of the important safety issues of high-parameter power plants. Herein, the Zr-based metal organic frameworks (Zr-MOFs) were applied to remove humic acid in water. The mesoporous and active sites of Zr-MOFs were controlled by different [...] Read more.
Humic acid (HA) in makeup water is one of the important safety issues of high-parameter power plants. Herein, the Zr-based metal organic frameworks (Zr-MOFs) were applied to remove humic acid in water. The mesoporous and active sites of Zr-MOFs were controlled by different ratios of ligands to increase the adsorption of HA. The maximum adsorption capacity was 150.15 mg g−1. The morphology and adsorption properties of the Zr-MOFs were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), surface charge, Fourier Transform infrared (FT-IR), N2 adsorption-desorption and adsorption test. The adsorption process of HA accorded with the pseudo-second-order kinetics, while the adsorption isotherm conformed to the Langmuir model and the adsorption was proved to be a spontaneous and endothermic process. Physical adsorption by the mesoporous materials and the hydrogen bonding interactions between the Zr-MOFs and HA were the driving forces of HA adsorption. These results provided useful information for the effective removal of HA and enhanced our understanding of the adsorption mechanism of HA on Zr-MOFs. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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12 pages, 1990 KiB  
Article
Bacterial Community Composition and Function in a Tropical Municipal Wastewater Treatment Plant
by Yaqiong Gu, Beiying Li, Xiang Zhong, Conghe Liu and Bin Ma
Water 2022, 14(10), 1537; https://doi.org/10.3390/w14101537 - 11 May 2022
Cited by 13 | Viewed by 2411
Abstract
Bacterial diversity and community composition are of great importance in wastewater treatment; however, little is known about the diversity and community structure of bacteria in tropical municipal wastewater treatment plants (WWTPs). Therefore, in this study, activated sludge samples were collected from the return [...] Read more.
Bacterial diversity and community composition are of great importance in wastewater treatment; however, little is known about the diversity and community structure of bacteria in tropical municipal wastewater treatment plants (WWTPs). Therefore, in this study, activated sludge samples were collected from the return sludge, anaerobic sludge, anoxic sludge, and aerobic sludge of an A2O WWTP in Haikou, China. Illumina MiSeq high-throughput sequencing was used to examine the 16S ribosomal RNA (rRNA) of bacteria in the samples. The microbial community diversity in this tropical WWTP was higher than in temperate, subtropical, and plateau WWTPs. Proteobacteria, Bacteroidota, Patescibacteria, and Chloroflexi were the dominant phyla. Nitrification bacteria Nitrosomonas, and Nitrospira were also detected. Tetrasphaera, instead of Candidatus Accumulibacter, were the dominant polyphosphate accumulating organisms (PAOs), while, glycogen accumulating organisms (GAOs), such as Candidatus Competibacter and Defluviicoccus were also detected. The bacterial community functions predicted by PICRUSt2 were related to metabolism, genetic information processing, and environmental information processing. This study provides a reference for the optimization of tropical municipal WWTPs. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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16 pages, 11295 KiB  
Article
Degradation of 2-Naphthol in Aqueous Solution by Electro-Fenton System with Cu-Supported Stainless Steel Electrode
by Xudong Cheng, Xiaoping Zhang, Shaoqi Zhou and Lin Shi
Water 2022, 14(7), 1007; https://doi.org/10.3390/w14071007 - 22 Mar 2022
Cited by 3 | Viewed by 2455
Abstract
For the treatment of 2-naphthol wastewater, the homogeneous electro-Fenton process was considered as an effective method but some disadvantages greatly restrict its application. The three-dimensional electro-Fenton (3D-EF) system using a nano zero-valent iron-supported biochar (NZVIs-BC) particle electrode and a Cu-supported stainless steel electrode [...] Read more.
For the treatment of 2-naphthol wastewater, the homogeneous electro-Fenton process was considered as an effective method but some disadvantages greatly restrict its application. The three-dimensional electro-Fenton (3D-EF) system using a nano zero-valent iron-supported biochar (NZVIs-BC) particle electrode and a Cu-supported stainless steel electrode (Cu-SSE) was proposed to avoid the disadvantages of the homogeneous electro-Fenton. In this work, the 3D-EF system was developed, which consisted of a Cu-SSE (cathode), a graphite rod (anode) and a NZVIs-BC particle electrode. The effect of the ratio of ferrous sulfate heptahydrate (FS) to rice straw (RS), CuSO4•5H2O amount, initial pH of 2-naphthol wastewater and current intensity (the output current of the power supply) on the removal rate of 2-naphthol were investigated. It is noteworthy that more than 98.36% of the 2-naphthol in aqueous solution was removed by the 3D-EF system, and only about 60.09% of 2-naphthol was removed by the homogeneous electro-Fenton system. Furthermore, naphthalene, benzoic acid, β-naphthoquinone, 1, 2-naphthalenedione, phenol and aromatic hydrocarbon were the main degradation products of 2-naphthol by the 3D-EF system; the toxicity of 2-naphthol wastewater was also greatly reduced. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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13 pages, 1589 KiB  
Article
Responses of Nitrogen Removal, Extracellular Polymeric Substances (EPSs), and Physicochemical Properties of Activated Sludge to Different Free Ammonia (FA) Concentrations
by Hongwei Sun, Yiran Li, Wei Tang, Huanhuan Chang, Cuizhong Chen and Chenjian Cai
Water 2022, 14(4), 620; https://doi.org/10.3390/w14040620 - 17 Feb 2022
Cited by 4 | Viewed by 1677
Abstract
To investigate the effect of free ammonia (FA) on the nitrogen removal performance, extracellular polymeric substances (EPSs), and physicochemical properties of activated sludge, four laboratory-scale sequencing batch reactors (SBRs) were operated at FA concentrations of 0.5, 5, 10, and 15 mg/L (R0.5 [...] Read more.
To investigate the effect of free ammonia (FA) on the nitrogen removal performance, extracellular polymeric substances (EPSs), and physicochemical properties of activated sludge, four laboratory-scale sequencing batch reactors (SBRs) were operated at FA concentrations of 0.5, 5, 10, and 15 mg/L (R0.5, R5, R10, and R15, respectively). Results showed that nitrogen removal and the production of EPSs and their components (including polysaccharides, proteins, and nucleic acid) significantly increased with the increased FA concentration from 0.5 to 10 mg/L; however, they decreased with a further increase in FA to 15 mg/L. Moreover, the capillary suction time (CST), specific resistance of filtration (SRF), and sludge volume index (SVI) decreased when FA concentration increased, indicating that better settleability and dewaterability of activated sludge was obtained. Additionally, a path diagram showed that Nitrosomonas was positively correlated, while Denitratisoma was negatively correlated with EPSs and their components. Thauera was positively correlated, while Zoogloea was negatively correlated with the settleability and de-waterability of activated sludge. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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12 pages, 2865 KiB  
Article
Pretreatment of Rubber Additives Processing Wastewater by Aluminum–Carbon Micro-Electrolysis Process: Process Optimization and Mechanism Analysis
by Ling Zhu, Daikuan Huang and Hao Du
Water 2022, 14(4), 582; https://doi.org/10.3390/w14040582 - 15 Feb 2022
Cited by 1 | Viewed by 1845
Abstract
The pretreatment of rubber additives processing wastewater was performed by Al/AC micro-electrolysis (ME). The single-factor experiments for the removal of COD and chroma were investigated. The Box-Behnken Design (BBD) was also applied to optimize the experimental conditions, and the fitted response surface model [...] Read more.
The pretreatment of rubber additives processing wastewater was performed by Al/AC micro-electrolysis (ME). The single-factor experiments for the removal of COD and chroma were investigated. The Box-Behnken Design (BBD) was also applied to optimize the experimental conditions, and the fitted response surface model supplied highly significant quadratic models for the process. The COD removal efficiency reached 51.6% at an initial pH of 9.8, Al scrap dosage of 98.6 g L−1, Al/AC mass ratio of 0.26, and reaction time of 176 min, which was reasonably consistent with the predicated value of 51.9%. Moreover, we proposed a reaction mechanism of the process for the degradation of organic contaminants, and found that the removal of COD and chroma were mainly ascribed to the combination of active hydrogen [H] with strong chemical reactivity and flocculation of aluminum hydroxide. All these results showed that Al/AC ME is a promising pretreatment technique for this wastewater. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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12 pages, 3146 KiB  
Article
Anaerobic Digestion for Biogas Production from Municipal Sewage Sludge: A Comparative Study between Fine Mesh Sieved Primary Sludge and Sedimented Primary Sludge
by Phillimon T Odirile, Potlako M Marumoloa, Anthoula Manali and Petros Gikas
Water 2021, 13(24), 3532; https://doi.org/10.3390/w13243532 - 10 Dec 2021
Cited by 13 | Viewed by 3517
Abstract
Two different types of primary sewage sludge have been used as feedstock for production of biogas through anaerobic digestion (AD): the one type was sludge from a typical primary clarifier (PC), while the other type of sludge produced by a rotating belt filter, [...] Read more.
Two different types of primary sewage sludge have been used as feedstock for production of biogas through anaerobic digestion (AD): the one type was sludge from a typical primary clarifier (PC), while the other type of sludge produced by a rotating belt filter, commonly called microsieve (MS). Initially the main physicochemical characteristics of the sludges, such as total solids (TS), volatile solids (VS), VS/TS, pH and carbon to nitrogen ratio (C/N) were determined, for MS: 37.86 ± 0.08%, 83.00 ± 0.41%, 0.83 ± 0.00, 6.67 ± 0.08 and 19.68 ± 0.69, respectively, and for PC: 2.61 ± 0.08%, 78.77 ± 1.91%, 0.79 ± 0.02, 6.61 ± 0.10 and 14.46 ± 1.23, respectively. Then, calculated amounts of the sludges were inserted into airtight vials and were inoculated using anaerobic sludge. The daily biogas production was measured over a period of 30 days. PC sludge maximized the daily biogas production (44.20 mlbiogas/gvsd) 11 days after inoculation, while the MS sludge reach a peak (37.74 mlbiogas/gvsd) 14 days after inoculation. The cumulative biogas production over the 30 days of AD was in the same laver (442.29 mlbiogas/gvs for PC versus 434.73 mlbiogas/gvs for MS). However, PC sludge indicated higher daily biogas production, compared to MS sludge, while the opposite was observed for the period following the peak point. The Volatile Solids Reduction for PC and MS sludges was recorded as 46.06% and 32.39%, respectively. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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10 pages, 2469 KiB  
Article
Comparative Study on Advanced Nitrogen Removal of Landfill Leachate Treated by SBR and SBBR
by Jinfeng Jiang, Liang Ma, Lianjie Hao, Daoji Wu and Kai Wang
Water 2021, 13(22), 3240; https://doi.org/10.3390/w13223240 - 16 Nov 2021
Cited by 5 | Viewed by 2584
Abstract
In order to achieve advanced nitrogen removal from landfill leachate without the addition of external carbon sources, a Sequencing Batch Reactor (SBR) and a Sequencing Biofilm Batch Reactor (SBBR) were proposed for the treatment of actual landfill leachate with ammonia nitrogen ( [...] Read more.
In order to achieve advanced nitrogen removal from landfill leachate without the addition of external carbon sources, a Sequencing Batch Reactor (SBR) and a Sequencing Biofilm Batch Reactor (SBBR) were proposed for the treatment of actual landfill leachate with ammonia nitrogen (NH4+-N) and chemical oxygen demand (COD) concentrations of 1000 ± 100 mg/L and 4000 ± 100 mg/L, respectively. The operating modes of both systems are anaerobic–aerobic–anoxic. After 110 days of start-up and biomass acclimation, the effluent COD and the total nitrogen (TN) of the two systems were 650 ± 50 mg/L and 20 ± 10 mg/L, respectively. The removal rates of COD and total nitrogen could reach around 85% and above 95%, respectively. Therefore, advanced nitrogen removal was implemented in landfill leachate without adding any carbon sources. After the two systems were acclimated, nitrogen removing cycles of SBR and SBBR were 24 h and 20 h, respectively. The nitrogen removing efficiency of SBBR was improved by 16.7% in comparison to SBR. In the typical cycle of the two groups of reactors, the nitrification time of the system was the same, which was 5.5 h, indicating that although the fiber filler occupied part of the reactor space, it had no significant impact on the nitrification performance of the system. At the end of aeration, the internal carbon source content of sludge of SBBR was equivalent to that of the SBR system. However, the total nitrogen concentration of SBBR was only 129 mg/L, which is 33.8% lower than that of SBR at 195 mg/L. The main reason was that biofilm enhanced the simultaneous nitrification and denitrification (SND) effect of the system. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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14 pages, 3618 KiB  
Article
Solvothermal Synthesis of ZnO Nanoparticles for Photocatalytic Degradation of Methyl Orange and p-Nitrophenol
by Ying Wang, Chuanxi Yang, Yonglin Liu, Yuqi Fan, Feng Dang, Yang Qiu, Huimin Zhou, Weiliang Wang and Yuzhen Liu
Water 2021, 13(22), 3224; https://doi.org/10.3390/w13223224 - 13 Nov 2021
Cited by 17 | Viewed by 3524
Abstract
The photocatalytic degradation of organic pollutants is an effective method of controlling environmental pollution. ZnO nanoparticles (ZnO NPs) were prepared by the solvothermal method and characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and [...] Read more.
The photocatalytic degradation of organic pollutants is an effective method of controlling environmental pollution. ZnO nanoparticles (ZnO NPs) were prepared by the solvothermal method and characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–visible diffuse reflectance spectroscopy (UV–Vis DRS). The results showed that the ZnO NPs had a uniform size of 25–40 nm, hexagonal wurtzite structure, and a band gap of 2.99 eV. The photocatalytic degradation of methyl orange (MO) and p-nitrophenol (PNP) was used as a model reaction to evaluate the photocatalytic activity of ZnO NPs. The photocatalytic degradation rates (pseudo-first-order kinetics) of MO and PNP were 92% (0.0128 min−1) and 56.2% (0.0042 min−1), respectively, with a 25 W ultraviolet lamp, MO/PNP concentration = 20 mg/L, ZnO NPs dose = 1.5 g/L, and time = 180 min. The photocatalytic mechanism of ZnO NPs and degradation pathways of MO and PNP were also proposed. The results provide valuable information and guidance for the treatment of wastewater via photocatalytic methods. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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11 pages, 987 KiB  
Review
Advances in the Study of Heavy Metal Adsorption from Water and Soil by Modified Biochar
by Yizhuo Wang, He Li and Shaohua Lin
Water 2022, 14(23), 3894; https://doi.org/10.3390/w14233894 - 29 Nov 2022
Cited by 12 | Viewed by 4256
Abstract
Heavy metal contamination in water and soil has gradually become a concern with the development of industry in recent years and may pose a serious threat to human health if left untreated. Biochar is commonly used as an adsorbent/immobilizer of heavy metals from [...] Read more.
Heavy metal contamination in water and soil has gradually become a concern with the development of industry in recent years and may pose a serious threat to human health if left untreated. Biochar is commonly used as an adsorbent/immobilizer of heavy metals from water and substrates because of its wide—ranging raw materials, low production cost, and good adsorption performance. Based on the adsorption mechanism of biochar, this paper analyzes different modification methods of biochar, aiming to provide an effective material for the treatment of heavy metals from water and sediment and provide a certain reference for its application to practical projects. Full article
(This article belongs to the Special Issue Advances in Wastewater Treatment: Resources Recovery, Energy Neutralization, Water Reuse)
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