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Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse

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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 (31 May 2021) | Viewed by 36785

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Special Issue Editor

Dr. Alexandros I. Stefanakis

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Guest Editor

Technical University of Crete, Chania, Greece
Department of Engineering, German University of Technology in Oman, Oman;
Bauer Nimr LLC, Muscat, Oman
Bauer Resources GmbH, Schrobenhausen, Germany
Interests: water engineering; wastewater treatment; wastewater technologies; wastewater reuse; hybrid systems; constructed wetlands; membrane filtration; activated carbon; advanced oxidation processes; sludge dewatering
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Special Issue Information

Dear Colleagues,

Access to clean water and fresh water conservation are the main challenges for the global society. In the new context of circular water economy, wastewater is viewed more as a valuable resource rather than a waste stream. However, this can only be accomplished through appropriate and effective treatment that will allow for treated effluents reuse and recycling. The modern wastewater engineering approach dictates the use of hybrid treatment systems, namely combinations of different physical, biological and chemical processes. The ultimate goal is to identify the optimum combinations that would provide not only efficient but also cost-effective and sustainable treatment schemes. Current experiences imply that the proper and careful selection of a hybrid wastewater treatment system can achieve these goals.

Therefore, this Special Issue aims at presenting the state-of-the-art of hybrid systems for wastewater treatment and the recent developments in the field of combining different technologies for various wastewaters, i.e., domestic, municipal, industrial, agro-industrial. Contributions will be accepted from both research projects and experiences from full-scale applications. Review papers summarizing the existing knowledge and technological status of different hybrid systems are also welcome, after coordination with the Special Issue Editor. The potential technologies used in hybrid systems include but are not limited to:

Activated sludge and its variants
Extended aeration
Membrane filtration (ultrafiltration, nanofiltration, microfiltration, reverse osmosis) & Membrane bioreactors
Sequencing batch reactors
Attached growth biofilm reactors
Moving bed biofilm reactors
Aerobic / anaerobic systems
Natural treatment systems such as constructed wetlands, stabilization ponds, etc.
Trickling filters
Upflow anaerobic sludge blanket reactors
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.

Dr. Alexandros I. Stefanakis
Guest Editor

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

water engineering
wastewater treatment
wastewater technologies
wastewater reuse
hybrid systems
membrane filtration
membrane bioreactor
constructed wetlands
activated sludge
activated carbon
advanced oxidation processes
chemical treatment

Published Papers (9 papers)

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Research

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10 pages, 2372 KiB

Open AccessArticle

Enhancement of Solar Water Desalination Using Copper and Aluminum Oxide Nanoparticles

by Mohammad A. Hamdan, Anas M. Al Momani, Osama Ayadi, Ahmad H. Sakhrieh and Francisco Manzano-Agugliaro

Water 2021, 13(14), 1914; https://doi.org/10.3390/w13141914 - 10 Jul 2021

Cited by 5 | Viewed by 2653

Abstract

In this research, two identical solar stills were designed and constructed to investigate the effect of adding copper and aluminum oxide nanoparticles on the quantity of water produced by solar desalination. The two solar stills were installed side by side, and measurements were recorded simultaneously from both stills. The nanoparticles were added to one still, each at one time but with different concentrations, while the other contained only water. Data acquisition and a weather station were used to record the glass, water, and ambient temperatures in addition to the hourly solar radiation. It was found that the addition of nanoparticles increases the amount of condensate. The most efficient concentrations were found to be 0.4% of Al₂O₃ and 0.6% of CuO. At these concentrations, an increase in the efficiency of the still equals 7.8%, and 9.62% was recorded. Furthermore, it was found that CuO has a more pronounced effect on the condensate than Al₂O₃ at all concentrations except at 0.4% concentration. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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19 pages, 3404 KiB

Open AccessFeature PaperArticle

Evaluation of Hybrid Constructed Wetland Performance and Reuse of Treated Wastewater in Agricultural Irrigation

by Michal Šereš, Petra Innemanová, Tereza Hnátková, Miloš Rozkošný, Alexandros Stefanakis, Jaroslav Semerád and Tomáš Cajthaml

Water 2021, 13(9), 1165; https://doi.org/10.3390/w13091165 - 23 Apr 2021

Cited by 11 | Viewed by 4543

Abstract

Agriculture is being negatively affected by the decrease in precipitation that has been observed over the last few years. Even in the Czech Republic, farmers are being urged to irrigate their fields despite the fact that sources of water for irrigation are rapidly being depleted. This problem might be partially solved via the reuse of treated wastewater in certain agricultural sectors. However, the public perception of the reuse of wastewater remains negative primarily due to unknown risks to the environment and public health. To overcome this barrier, a semi-operated irrigation field was established at Kostelec nad Ohří in the Central Bohemian region of the Czech Republic and planted with common garden crops such as tomatoes (Lycopersicon esculentum), potatoes (Solanum tuberosum) and lettuces (Lactuca sativa L.) irrigated with two different water sources, i.e., treated wastewater from a local nature-based treatment system, a hybrid constructed wetland (HCW), and local fresh water from well. The HCW was put into operation in 2017 and was reconstructed in 2018 and includes both horizontal and vertical flow beds; the trial irrigation field was added in the same year. The reconstruction of the facility significantly enhanced the removal efficiency with respect to all monitored parameters, e.g., biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), N–NH₄⁺, total N and the suspended solids (TSS), except for total P. The HCW also ensured the significant removal of several observed pathogenic microorganisms (E. coli, intestinal enterococci and thermotolerant coliforms). During the 2018 and 2019 growing seasons, we observed the significantly enhanced growth of the crops irrigated with wastewater from the HCW due to the fertilizing effect. The risks associated with the contamination of crops irrigated with treated water are not negligible and it is necessary to pay sufficient attention to them, especially when introducing irrigation with wastewater into practice. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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11 pages, 2433 KiB

Open AccessArticle

Investigating the Result of Current Density, Temperature, and Electrolyte Concentration on COD: Subtraction of Petroleum Refinery Wastewater Using Response Surface Methodology

by Sharon Chakawa and Mujahid Aziz

Water 2021, 13(6), 835; https://doi.org/10.3390/w13060835 - 18 Mar 2021

Cited by 11 | Viewed by 2130

Abstract

Electrochemical oxidation (EO) investigated chemical oxygen demand (COD) subtraction from petroleum refinery wastewater (PRW) as a capable remediation process. Titanium substrates coated with iridium–tantalum oxide mixtures (Ti/IrO₂–Ta₂O₅) were used as the dimensional stable anode (DSA). The Box-Behnken Design (BBD), a statistical experimental design and response surface methodology (RSM), was used to matrix the current density, temperature, and electrolyte (NaCl) concentration variables, with COD removal efficiency as the response factor. A second-order verifiable relationship between the response and independent variables was derived where the analysis of variance displayed a high coefficient of determination value (R² = 0.9799). The predicted values calculated with the model equations were very close to the experimental values where the model was highly significant. Based on the BBD for current density, the optimum process conditions, temperature and electrolyte (NaCl) concentration were 7.5 mA/cm², 42 °C and 4.5 g/L, respectively. They were resulting in a COD removal efficiency of 99.83% after a 12-hour EO period. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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10 pages, 472 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Contamination of Surface Water and River Sediments by Antibiotic and Antiretroviral Drug Cocktails in Low and Middle-Income Countries: Occurrence, Risk and Mitigation Strategies

by Pius Kairigo, Elijah Ngumba, Lotta-Riina Sundberg, Anthony Gachanja and Tuula Tuhkanen

Water 2020, 12(5), 1376; https://doi.org/10.3390/w12051376 - 13 May 2020

Cited by 50 | Viewed by 4777

Abstract

Presence of antimicrobial cocktails in the hydrological cycles is of interest because of their potential to mediate antimicrobial resistance within the natural environment. In this study, we determined the concentrations of selected antibiotics and antiretroviral drugs (ARVDs) in wastewater treatment plant (WWTP) effluent, effluent suspended particulate matter (SPM), surface waters and river sediments in Kenya in order to determine the extent of pollution within the sampled environment. Target analysis for the most common antibiotics and ARVDs was done. Sulfamethoxazole (SMX), ciprofloxacin (CIP), trimethoprim (TMP), norfloxacin (NOR), zidovidine (ZDV), lamivudine (3TC) and nevirapine (NVP) were analyzed using LC-ESI-MS/MS. Effluent aqueous phase had concentrations ranging between 1.2 µg L⁻¹ to 956.4 µg L⁻¹ while the effluent SPM showed higher concentrations, ranging between 2.19 mg Kg⁻¹ and 82.26 mg Kg⁻¹. This study shows emission of active pharmaceutical ingredients (APIs) from WWTP to the environment mainly occurs via the SPM phase, which is usually overlooked in environmental analyses. Concentrations in surface waters and river sediments ranged between 1.1 µg L⁻¹ to 228 µg L⁻¹ and 11 µg Kg⁻¹ to 4125 µg Kg⁻¹ respectively. ARVDs occurred at consistently higher concentrations than antibiotics in both the aqueous and solid samples. The wastewater treatment plants and lagoons where sludge degradation should occur, are sources of active pharmaceutical ingredients (APIs) including transformational products, nutrients and organic matter that are released back to the aqueous phase. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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15 pages, 4595 KiB

Open AccessEditor’s ChoiceArticle

Removal of Pharmaceuticals, Toxicity and Natural Fluorescence by Ozonation in Biologically Pre-Treated Municipal Wastewater, in Comparison to Subsequent Polishing Biofilm Reactors

by Kai Tang, Gordon T. H. Ooi, Aikaterini Spiliotopoulou, Kamilla M. S. Kaarsholm, Kim Sundmark, Bianca Florian, Caroline Kragelund, Kai Bester and Henrik R. Andersen

Water 2020, 12(4), 1059; https://doi.org/10.3390/w12041059 - 8 Apr 2020

Cited by 7 | Viewed by 3390

Abstract

Ozonation followed by a polishing moving bed biofilm reactor (MBBR) was implemented in pilot and laboratory to remove the residual pharmaceuticals and toxicity from wastewater effluent, which was from a pilot hybrid system of MBBR and activated sludge, receiving municipal wastewater. The delivered ozone dosages achieving 90% pharmaceutical removal were determined both in pilot and laboratory experiments and they were normalised to dissolved organic carbon (DOC), illustrating our findings were comparable with previously published literature. During wastewater ozonation, the intensity of natural fluorescence was found to be greatly associated with the concentrations of the studied pharmaceuticals. In pilot experiments, toxicity, measured by Vibrio fischeri, increased after ozonation at delivered ozone dosages at 0.38–0.47 mg O₃/mg DOC and was completely removed by the subsequent polishing MBBR. Laboratory experiments verified that the polishing MBBR was able to remove the toxicity produced by the ozonation. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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16 pages, 3807 KiB

Open AccessArticle

Nutrient Recovery from Anaerobically Treated Blackwater and Improving Its Effluent Quality through Microalgae Biomass Production

by Melesse Eshetu Moges, Arve Heistad and Thorsten Heidorn

Water 2020, 12(2), 592; https://doi.org/10.3390/w12020592 - 21 Feb 2020

Cited by 20 | Viewed by 4417

Abstract

The blackwater stream of domestic wastewater contains energy and the majority of nutrients that can contribute to a circular economy. Hygienically safe and odor-free nutrient solution produced from anaerobically treated source-separated blackwater through an integrated post-treatment unit can be used as a source of liquid fertilizer. However, the high water content in the liquid fertilizer represents a storage or transportation challenge when utilized on agricultural areas, which are often situated far from the urban areas. Integration of microalgae into treated source-separated blackwater (BW) has been shown to effectively assimilate and recover phosphorus (P) and nitrogen (N) in the form of green biomass to be used as slow release biofertilizer and hence close the nutrient loop. With this objective, a lab-scale flat panel photobioreactor was used to cultivate Chlorella sorokiniana strain NIVA CHL 176 in a chemostat mode of operation. The growth of C. sorokiniana on treated source-separated blackwater as a substrate was monitored by measuring dry biomass concentration at a dilution rate of 1.38 d⁻¹, temperature of 37 °C and pH of 7. The results indicate that the N and P recovery rates of C. sorokiniana were 99 mg N L⁻¹d⁻¹ and 8 mg P L⁻¹d⁻¹ for 10% treated BW and reached 213 mg N L⁻¹d⁻¹ and 35 mg P L⁻¹d⁻¹, respectively when using 20% treated BW as a substrate. The corresponding biomass yield on light, N and P on the 20% treated BW substrate were 0.37 g (mol photon)⁻¹, 9.1 g g⁻¹ and 54.1 g g⁻¹, respectively, and up to 99% of N and P were removed from the blackwater. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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Review

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17 pages, 750 KiB

Open AccessEditor’s ChoiceReview

Sustainable, Decentralized Sanitation and Reuse with Hybrid Nature-Based Systems

by Andrea G. Capodaglio, Silvia Bolognesi and Daniele Cecconet

Water 2021, 13(11), 1583; https://doi.org/10.3390/w13111583 - 3 Jun 2021

Cited by 25 | Viewed by 4094

Abstract

Nature (ecosystem) based processes for wastewater treatment include constructed wetlands (CWs), waste stabilization ponds, vegetated drainage ditches, buffer zones, instream or bankside river techniques, and mixotrophic systems, where light and CO₂ are utilized, in addition to organic carbon compounds, by algal cultures. Algae-based systems can simultaneously remove organic matter, N, and P and may offer substantial energetic advantages compared to traditional biological treatment systems, require small spatial footprint, and contribute to biofuels production and CO₂ emissions mitigation. Bioelectrochemical systems (BES) such as microbial fuel cells (MFCs) present characteristics compatible with the use in isolated realities for water and wastewater treatment with contextual energy recovery and may be combined with other nature-based process technologies to achieve good treatment and energy efficiencies. Despite that their application in real-scale plants has not been assessed yet, the most probable outcome will be the in situ/on site treatment (or pretreatment) of wastes for small “in house” plants not connected to the sewerage network. This paper focuses on the current practices and perspectives of hybrid nature-based systems, such as constructed wetlands and microalgae integrated phytoremediation plants, and their possible integration with microbial electrochemical technologies to increase recovery possibilities from wastes and positively contribute to a green economy approach. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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34 pages, 4083 KiB

Open AccessReview

Catalytic Ozonation and Membrane Contactors—A Review Concerning Fouling Occurrence and Pollutant Removal

by Savvina Psaltou and Anastasios Zouboulis

Water 2020, 12(11), 2964; https://doi.org/10.3390/w12112964 - 22 Oct 2020

Cited by 22 | Viewed by 3422

Abstract

Membrane filtration has been widely used in water and wastewater treatment. However, this process is not very effective for the removal of refractory organic compounds (e.g., of pharmaceutical origin). Coupling membrane filtration with ozonation (or other Advanced Oxidation Methods) can enhance the degradation of these compounds and, subsequently, the incidence of membrane fouling (i.e., the major problem of membrane uses) would be also limited. Ozonation is an efficient oxidative process, although ozone is considered to be a rather selective oxidant agent and sometimes it presents quite low mineralization rates. An improvement of this advanced oxidation process is catalytic ozonation, which can decrease the by-product formation via the acceleration of hydroxyl radicals production. The hydroxyl radicals are unselective oxidative species, presenting high reaction constants with organic compounds. An efficient way to couple membrane filtration with catalytic ozonation is the deposition of an appropriate solid catalyst onto the membrane surface. However, it must be noted that only metal oxides have been used as catalysts in this process, while the membrane material can be of either polymeric or ceramic origin. The relevant studies regarding the application of polymeric membranes are rather scarce, because only a few polymeric materials can be ozone-resistant and the deposition of metal oxides on their surface presents several difficulties (e.g., affinity etc.). The respective literature about catalytic membrane ozonation is quite limited; however, some studies have been performed concerning membrane fouling and the degradation of micropollutants, which will be presented in this review. From the relevant results it seems that this hybrid process can be an efficient technology both for the reduction of fouling occurrence as well as of enhancement of micropollutant removal, when compared to the application of single filtration or ozonation. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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20 pages, 1806 KiB

Open AccessReview

Recent Developments and Future Challenges of Hydrogels as Draw Solutes in Forward Osmosis Process

by Jichao Wang, Shanshan Gao, Jiayu Tian, Fuyi Cui and Wenxin Shi

Water 2020, 12(3), 692; https://doi.org/10.3390/w12030692 - 3 Mar 2020

Cited by 33 | Viewed by 5660

Abstract

Forward osmosis (FO) has been recently regarded as a promising water treatment technology due to its lower energy consumption and lower membrane fouling propensity compared to the reverse osmosis (RO). The absence of suitable draw solute constraints the wide-range application of the FO. Hydrogels are three-dimensional hydrophilic polymer networks that can absorb a huge amount of water. Particularly, stimuli-responsive polymer hydrogels can undergo a reversible volume change or solution-gel phase transition in response to external environmental stimuli, including temperature, light, pressure, solvent composition, and pH. These intrinsic properties indicate the lowest regeneration cost of draw solutes compared to the thermal method and other membrane processes. This review aims to introduce the research progress on hydrogels as draw solutes, clarify the existing problems and point out the further research direction. Full article

(This article belongs to the Special Issue Hybrid Systems Using Different Technologies for Wastewater Treatment and Reuse)

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