Special Issue "Water Quality Engineering and Wastewater Treatment Ⅱ"

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

Deadline for manuscript submissions: closed (1 July 2022) | Viewed by 13793

Special Issue Editors

Prof. Dr. Yung-Tse Hung
E-Mail Website
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. Hamidi Abdul Aziz
E-Mail Website
Guest Editor
School of Civil Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia
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. Issam A. Al-Khatib
E-Mail Website
Guest Editor
Institute of Environmental and Water Studies, Faculty of Graduate Studies, Birzeit University, PO Box 14 west Bank, Palestine
Interests: water recourses management and quality; environmental assessment; wastewater management; advocacy; coordination and networking
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Rehab O. Abdel Rahman
E-Mail Website
Guest Editor
Hot Lab. & Waste Manag. Center, Atomic Energy Authority of Egypt, Inshas, P.O. 13759 Cairo, Egypt
Interests: radioactive waste management; wastewater treatment; natural and synthetic materials assessments; pollution control
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Tsuyoshi Imai
E-Mail Website
Guest Editor
Graduate School of Sciences and Technology for Innovation, Yamaguchi University, 2-16-1, Tokiwadai, Ube city, Yamaguchi 755-8611, Japan
Interests: municipal wastewater treatment; industrial waste treatment; biological waste treatment and recycle; tap water treatment; water pollution control; water quality engineering

Special Issue Information

Clean water is one of the most important natural resources on earth. Wastewater, which is spent water, is also a valuable natural resource in the world. However, wastewater may contain many contaminants and cannot be released back into the environment until the contaminants are removed. Untreated wastewater and inadequately treated wastewater may have a detrimental effect on the environment and a harmful effect on human health. Water quality engineering addresses the sources, transport, and treatment of chemical and microbiological contaminants that affect water. Our objective is the treatment of wastewater so that the treated wastewater can meet national effluent standards for the protection of the environment and the protection of public health.

This Special Issue aims to seek contributions on advanced technologies applied to the treatment of municipal and industrial wastewater and sludge. We seek contributions that deal with recent advances in municipal wastewater, industrial wastewater, and sludge-treatment technologies; the health effects of municipal wastewater; risk management; energy-efficient wastewater treatment; water sustainability; and water reuse and resource recovery.

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

Manuscript Submission Information

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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 2200 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

  • advanced wastewater technology
  • onsite wastewater treatment
  • natural wastewater treatment system
  • biological treatment
  • physicochemical treatment
  • tertiary treatment
  • water quality
  • sludge treatment and disposal
  • energy-efficient wastewater treatment
  • water reuse
  • resource recovery
  • municipal wastewater
  • industrial wastewater
  • nutrient removal

Published Papers (18 papers)

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Research

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Article
Artificial Neural Network (ANN) Modelling for Biogas Production in Pre-Commercialized Integrated Anaerobic-Aerobic Bioreactors (IAAB)
Water 2022, 14(9), 1410; https://doi.org/10.3390/w14091410 - 28 Apr 2022
Viewed by 523
Abstract
The use of integrated anaerobic-aerobic bioreactor (IAAB) to treat the Palm Oil Mill Effluent (POME) showed promising results, which successfully overcome the limitation of a large space that is needed in the conventional method. The understanding of synergism between anaerobic digestion and aerobic [...] Read more.
The use of integrated anaerobic-aerobic bioreactor (IAAB) to treat the Palm Oil Mill Effluent (POME) showed promising results, which successfully overcome the limitation of a large space that is needed in the conventional method. The understanding of synergism between anaerobic digestion and aerobic process is required to achieve maximum biogas production and COD removal. Hence, this work presents the use of artificial neural network (ANN) to predict the COD removal (%), purity of methane (%), and methane yield (LCH4/gCODremoved) of anaerobic digestion and COD removal (%), biochemical oxygen demand (BOD) removal (%), and total suspended solid (TSS) removal (%) of aerobic process in a pre-commercialized IAAB located at Negeri Sembilan, Malaysia. MATLAB R2019b was used to develop the two ANN models. Bayesian regularization backpropagation (BR) showed the best performance among the 12 training algorithms. The trained ANN models showed high accuracy (R2 > 0.997) and demonstrated good alignment with the industrial data obtained from the pre-commercialized IAAB over a 6-month period. The developed ANN model is subsequently used to create the optimal operating conditions which maximize the output parameters. The COD removal (%) was improved by 33.9% (from 68.7% to 92%), while the methane yield was improved by 13.4% (from 0.23 LCH4/gCODremoved to 0.26 LCH4/gCODremoved). Sensitivity analysis shows that COD inlet is the most influential input parameters that affect the methane yield, anaerobic COD, BOD and TSS removals, while for aerobic process, COD removal is most affected by mixed liquor suspended solids (MLSS). The trained ANN model can be utilized as a decision support system (DSS) for operators to predict the behavior of the IAAB system and solve the problems of instability and inconsistent biogas production in the anaerobic digestion process. This is of utmost importance for the successful commercialization of this IAAB technology. Additional input parameters such as the mixing time, reaction time, nutrients (ammonium nitrogen and total phosphorus) and concentration of microorganisms could be considered for the improvement of the ANN model. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Anaerobic Co-Digestion of Food Waste with Sewage Sludge: Simulation and Optimization for Maximum Biogas Production
Water 2022, 14(7), 1075; https://doi.org/10.3390/w14071075 - 29 Mar 2022
Cited by 1 | Viewed by 738
Abstract
Anaerobic co-digestion (ACD), where two or more substrates are digested simultaneously, is able to prevent the problems associated with mono-digestion. The aim of this study is to develop a simulation model of ACD of food waste (FW) with sewage sludge (SS) for biogas [...] Read more.
Anaerobic co-digestion (ACD), where two or more substrates are digested simultaneously, is able to prevent the problems associated with mono-digestion. The aim of this study is to develop a simulation model of ACD of food waste (FW) with sewage sludge (SS) for biogas production coupled with pre-treatment, sludge handling and biogas upgrading using SuperPro Designer v9.0. The Design Expert v13 is employed to perform optimization and evaluate the effect of hydraulic retention time (HRT), sludge recycle ratio, water to feed ratio (kg/kg) and SS to FW ratio (kg/kg) on the methane flow, chemical oxygen demand (COD) and volatile solids (VS). The results show that the methane yield of 0.29 L CH4/g COD removed, COD removal efficiency of 81.5% and VS removal efficiency of 69.2% are obtained with a HRT of 38.8 days, water to feed ratio (kg/kg) of 0.048, sludge recycle ratio of 0.438 and SS to FW ratio (kg/kg) of 0.044. Economic analysis has shown this study is feasible with a payback time of 6.2 years, net present value (NPV) of $5,283,000 and internal return rate (IRR) of 10.2%. This indicates that the ACD of FW and SS is economically feasible in a larger scale. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Cesspits as Onsite Sanitation Facilities in the Non-Sewered Palestinian Rural Areas: Users’ Satisfaction, Needs and Perception
Water 2022, 14(6), 849; https://doi.org/10.3390/w14060849 - 09 Mar 2022
Viewed by 420
Abstract
The main aim of this research was to assess the problems of using cesspits in the non-sewered areas in the West Bank of Palestine by the means of a questionnaire, with a sample size of 485 households, targeting the cesspits’ owners. People who [...] Read more.
The main aim of this research was to assess the problems of using cesspits in the non-sewered areas in the West Bank of Palestine by the means of a questionnaire, with a sample size of 485 households, targeting the cesspits’ owners. People who use cesspits for house onsite wastewater management are not satisfied with them, and most of them complain about high disturbance during discharge of the cesspits (75.5%). Emptying cesspits represents a financial burden, costing 6% of the households’ monthly income. The frequency of cesspits’ emptying decreases substantially when there are onsite GWTPs. People accept that constructing a house with an onsite GWTPs when supported by external funding, and to a much lesser extent when they need to fund them themselves. The majority of people prefer sewerage networks for wastewater management(74.8%), followed by onsite GWTPs (15.5%), and cesspits are the least preferable (9.5%). Therefore, a more technically sound individual home onsite wastewater management system should be applied to replace cesspits so as to solve their negative implications on the socio-economic, environmental, and health aspects in the Palestinian rural communities. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Swine Wastewater Treatment in Constructed Wetland Systems: Hydraulic and Kinetic Modeling
Water 2022, 14(5), 681; https://doi.org/10.3390/w14050681 - 22 Feb 2022
Cited by 1 | Viewed by 502
Abstract
The use of constructed wetland systems (CWS) is presented as an alternative for the treatment of effluents since these have reduced implementation costs and relative ease of operation. The present research was undertaken to evaluate to study the hydrodynamic and the fitting of [...] Read more.
The use of constructed wetland systems (CWS) is presented as an alternative for the treatment of effluents since these have reduced implementation costs and relative ease of operation. The present research was undertaken to evaluate to study the hydrodynamic and the fitting of first-order mathematical kinetic models for the removal of pollutants in CWS. Three CWS were built, using expanded clay as filter support: one cultivated with Polygonum punctatum (CWSw), another cultivated with Chrysopogon zizanioides (CWSV), and a control unit (CWSc). The actual retention time was 3.12 days in the CWSc, whereas, in the CWSw and CWSv, we observed values of 4.14 and 4.11 days, respectively. The dispersion values were high in all CWS. The values of chemical oxygen demand (COD) across the length of the CWS were used to fit the kinetic models that describe the first-order decay of organic matter over the CWS. The models that showed a better fit to the experimental data were the plug-flow with residual concentration, the continuous stirred tank reactor, and Shepherd’s models. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
The Impact of Electric Bidet Diffusion on Municipal Water Infrastructure
Water 2022, 14(4), 639; https://doi.org/10.3390/w14040639 - 18 Feb 2022
Viewed by 387
Abstract
Electric bidets have become widespread in Japan and are now rapidly being installed across the rest of Asia, the United States, and the European Union. However, the impact on water infrastructure has not yet been sufficiently evaluated. Using Japan as an example, we [...] Read more.
Electric bidets have become widespread in Japan and are now rapidly being installed across the rest of Asia, the United States, and the European Union. However, the impact on water infrastructure has not yet been sufficiently evaluated. Using Japan as an example, we assess the impact of the spread of electric bidets on the existing water infrastructure and use the results to predict the impact in countries in which the spread of electric bidets is expected in the future. In this study, we first proposed a model of electric bidet use on the basis of the results of a questionnaire survey. In Japan, the frequency of electric bidet use is considered to be the same as that of toilet use, and this model is used by the Ministry of Economy, Trade and Industry (METI) in its official evaluation of equipment performance. However, in this survey, we found that 30–40% of respondents did not use electric bidets, even though they have become commonplace in Japan. The reason for this was a vague sense of anxiety about sanitation. Based on the results of the survey, the model for electric bidet use was set to once a day for men for flushing following defecation and once a day for women for either flushing following defecation or bidet flushing. This is considerably less frequent than the conventional Japanese electric bidet use model for women, which models for one flush following defecation and three flushes following urination. Japan’s Energy Conservation Law requires improved energy efficiency in 32 items of equipment, of which the electric bidet is one. Because of this regulation, the electricity consumption of electric bidets has decreased by one fourth in the past 10 years. When a new model representing actual usage was applied, the environmental impact of the electric bidets currently sold was shown to be minimal. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Evaluating Permeable Clay Brick Pavement for Pollutant Removal from Varying Strength Stormwaters in Arid Regions
Water 2022, 14(3), 491; https://doi.org/10.3390/w14030491 - 07 Feb 2022
Viewed by 480
Abstract
Permeable pavement is a low impact development technology for stormwater (SW) runoff control and pollutant removal. The strength of SW depends on land use of the catchment, e.g., semi-urban vs. industrial. The performance (in terms of pollutants removal) of permeable clay bricks (PCB) [...] Read more.
Permeable pavement is a low impact development technology for stormwater (SW) runoff control and pollutant removal. The strength of SW depends on land use of the catchment, e.g., semi-urban vs. industrial. The performance (in terms of pollutants removal) of permeable clay bricks (PCB) has not been adequately assessed for SW of varying strengths. For using the permeable clay bricks as a pavement surface layer, the present research investigates its pollutant removal capacity through SW infiltration using a laboratory setup. SW samples of two different strengths, i.e., high polluted stormwater (HPSW) and less polluted stormwater (LPSW), were tested for a pavement system consisting of the clay brick layer on top of a coarse gravel support layer. The tests were performed at a rainfall intensity of 12.5 mm/h (for a 10-year return period in Buraidah, Qassim) to evaluate the suitability of PCB for the arid and semi-arid regions. The experiments revealed that PCB became fully saturated and achieved a steady-state outflow condition after 10 min of rainfall. Irrespective of contamination level, the pollutant removal efficiency was found to be similar for both HPSW and LPSW. High TSS (>98%) and turbidity (>99%) removals were achieved for both strengths, while BOD5 (78.4%) and COD (76.1%) removals were moderate. Poor to moderate nutrient removal, 30.5% and 39.1% for total nitrogen (TN) and 34.7% and 31.3% for total phosphorus (TP), respectively for HPSW and LPSW, indicates an adsorptive removal of nutrients in the system. Heavy metal removal efficiency ranged from 6.7% to 94%, with higher removals archived for Fe, Mn, Se, and Pb. The study provides insights into the role of PCB as a surface layer in the permeable pavement for pollutant removal. The study also establishes the guidelines for the optimal permeable pavement design to deal with SW of varying contamination levels. Permeable clay bricks showed the potential to be used as a sustainable LID technology for arid regions. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Exploring the Removal of Organic Matter in Constructed Wetlands Using First Order Kinetic Models
Water 2022, 14(3), 472; https://doi.org/10.3390/w14030472 - 05 Feb 2022
Viewed by 481
Abstract
Mathematical models have become an excellent tool to evaluate the characteristics and performance of Constructed Wetlands (CWs). They help to characterize the dynamics of pollutant removal in these systems. The aim of this research was to evaluate the kinetics of organic matter removal [...] Read more.
Mathematical models have become an excellent tool to evaluate the characteristics and performance of Constructed Wetlands (CWs). They help to characterize the dynamics of pollutant removal in these systems. The aim of this research was to evaluate the kinetics of organic matter removal in CWs using two models: (i) the conventional first order model and (ii) the sigmoidal or k-n model. For this purpose, data from 41 CWs where domestic sewage is treated were used. The cluster analysis was performed to identify similar groups of CWs based on the estimation of model coefficients. According to the results obtained, the model that provides a better fit for the removal of organic matter in CWs is the sigmoidal-type. However, its “n” coefficient, which would represent an increase in resistance to degradation, remains a not totally explained variable. The sigmoidal or k-n model is promising, presenting good adjustment indices. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Regression Tree Ensemble Rainfall–Runoff Forecasting Model and Its Application to Xiangxi River, China
Water 2022, 14(3), 463; https://doi.org/10.3390/w14030463 - 04 Feb 2022
Viewed by 514
Abstract
The development of an efficient and accurate hydrological forecasting model is essential for water management and flood control. In this study, the ensemble model was applied to predict the daily discharge; it not only could enhance the algorithm and improve the learning accuracy, [...] Read more.
The development of an efficient and accurate hydrological forecasting model is essential for water management and flood control. In this study, the ensemble model was applied to predict the daily discharge; it not only could enhance the algorithm and improve the learning accuracy, but it was also the most effective representative model among various combinations of learning parameters. Using the survey data of Xingshan station in Xiangxi River, China, the suitability of the model was proven. The performance of the ensemble model was compared with the multiple linear regression model and the artificial neural network models. Furthermore, the length of the training samples and the peak value predictions were analyzed. The results showed that, firstly, the best effect of the discharge simulation model appeared in the ensemble model, while the simulation accuracy of the multiple linear regression model was lower than that of the artificial neural network model in some cases. Secondly, the prediction effect of the ensemble model for discharge was better than that of the single model to some extent, whereby the maximum absolute value of relative error was 8.11% using the ensemble model. A comprehensive analysis showed that the ensemble model was optimal. Furthermore, the ensemble model performed outstandingly in terms of hydrological forecasting. The ensemble model also provided theoretical support for hydrological forecasting and could be considered as an alternative to multiple linear regression models and artificial neural networks. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Kinetic Study of the Anaerobic Digestion of Recycled Paper Mill Effluent (RPME) by Using a Novel Modified Anaerobic Hybrid Baffled (MAHB) Reactor
Water 2022, 14(3), 390; https://doi.org/10.3390/w14030390 - 27 Jan 2022
Viewed by 656
Abstract
The process kinetics of an anaerobic digestion process for treating recycled paper mill effluent (RPME) was investigated. A laboratory-scale modified anaerobic hybrid baffled reactor (MAHB) was operated at hydraulic retention times of 1, 3, 5, and 7 days, and the results were analyzed [...] Read more.
The process kinetics of an anaerobic digestion process for treating recycled paper mill effluent (RPME) was investigated. A laboratory-scale modified anaerobic hybrid baffled reactor (MAHB) was operated at hydraulic retention times of 1, 3, 5, and 7 days, and the results were analyzed for the kinetic models. A kinetic study was conducted by examining the phase kinetics of the anaerobic digestion process, which were divided into three main stages: hydrolysis kinetics, acetogenesis kinetics, and methane production kinetics. The study demonstrated that hydrolysis was the rate-limiting step. The applied Monod and Contois kinetic models showed satisfactory prediction with μmax values of 1.476 and 0.6796 L day−1, respectively. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Groundwater Quality of Drinking Water Wells in the West Bank, Palestine
Water 2022, 14(3), 377; https://doi.org/10.3390/w14030377 - 26 Jan 2022
Viewed by 731
Abstract
Groundwater, the main drinking water source in the West Bank, is highly vulnerable to pollution given the karstic nature of the aquifer. This study was aimed at screening the quality of groundwater used for water supply, in terms of physicochemical and microbiological properties, [...] Read more.
Groundwater, the main drinking water source in the West Bank, is highly vulnerable to pollution given the karstic nature of the aquifer. This study was aimed at screening the quality of groundwater used for water supply, in terms of physicochemical and microbiological properties, and heavy metals concentrations. Attention was given to groundwater chemistry, using piper and Durov diagrams, to assess potent impact of pollution on groundwater. Twenty-nine groundwater samples from selected wells, representing the different groundwater fields in the West Bank, were collected and analyzed. The results revealed that the concentration of the ions and parameters affecting the aesthetic and health related water quality, such as Cl, Na+, NH4+, TDS, and NO3, and selected (semi) metals, including Cr, Cu, Fe, Mn, Pb, Cd, and As, are within the limits recommended for drinking water. The dominant cations and anions were in the order of Ca2+ > Na+ > Mg2+ > K+ > NH4+ and HCO3 > Cl > NO3 > SO42−, respectively. The total average groundwater hardness is approximately 2.1 mmol/L and can be attributed to calcium (approximately 60%) and magnesium. The major ground water types in the West Bank were fresh water (Ca-Mg-HCO3), fresh water mixed with another water type (Ca-Mg-Na-HCO3 or Ca-Mg-HCO3-Cl), and extreme water type (Na-Ca-Mg-HCO3-Cl or Na-Ca-HCO3-Cl) showing high TDS, Cl and Na+. Signs of pollution, namely elevated levels of nitrate and ammonium, were, however, observed even in some deep wells (>600 m), despite the thick cover of soil, tapping the Lower Ceneomanian confined aquifer. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Effect of the Progressive Increase of Organic Loading Rate in an Anaerobic Sequencing Batch Reactor for Biodiesel Wastewater Treatment
Water 2022, 14(2), 223; https://doi.org/10.3390/w14020223 - 12 Jan 2022
Cited by 3 | Viewed by 424 | Correction
Abstract
The wastewater from the biodiesel industry is an environmental problem, and from a sanitation resources perspective, the anaerobic sequencing batch reactor (ASBR) is an interesting alternative for wastewater treatment. A better understanding of ASBR operation behavior under the progressive increase of the organic [...] Read more.
The wastewater from the biodiesel industry is an environmental problem, and from a sanitation resources perspective, the anaerobic sequencing batch reactor (ASBR) is an interesting alternative for wastewater treatment. A better understanding of ASBR operation behavior under the progressive increase of the organic loading rate (OLR) is crucial for upscaling. The objective of this study was to monitor an ASBR operating with an OLR ranging from 1.3 to 9.3 kgCOD m−3 d−1. The average chemical oxygen demand (COD) removal efficiencies of the ASBR were 52, 41, 47, and 11% for phases 1, 2, 3, and 4, respectively. The apparent kinetic coefficient, i.e., the rate of degradation of organic matter, was between 0.10 and 1.80 h−1, considering the kinetic model that considers the residual substrate concentration, which was the one that best fit the obtained data. The progressive increase in applied OLR modified the microbial biomass diversity, which in turn influenced the degradation kinetics of the organic matter. In addition, the values of the applied OLR of 5.1 kgCOD m−3 d−1 and a food to microorganism ratio (F/M) of 0.6 kgCOD kgVSS−1 d−1 were shown to be limiting values that promoted the overload of ASBR. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Use of Stainless-Steel Electrodes on the Electrochemical Oxidation of Naproxen and its Transformation Products in Surface Water
Water 2021, 13(24), 3604; https://doi.org/10.3390/w13243604 - 15 Dec 2021
Viewed by 791
Abstract
In this study, stainless-steel electrodes were used to effectively oxidize naproxen and its transformation products in surface water by electrochemical oxidation in short reaction times. An evaluation of the effects of current density, chloride concentrations, and pH on the electrochemical oxidation process (mechanisms, [...] Read more.
In this study, stainless-steel electrodes were used to effectively oxidize naproxen and its transformation products in surface water by electrochemical oxidation in short reaction times. An evaluation of the effects of current density, chloride concentrations, and pH on the electrochemical oxidation process (mechanisms, kinetics, and reaction times) was conducted. Results showed that degradation rates of naproxen were greater, and the reaction times were shorter than those reported in other studies for other compounds and electrode materials. Oxidation naproxen and its transformation products were faster at high current densities, high chloride concentrations, and low pH conditions; however, good performance of the electrochemical oxidation process was observed at 16.3 mA/cm2 and pH 5 for both the naproxen and its transformation products, which were oxidized in only 15 min for the treated effluent and 30 min in the case of sludge. At pH 3 and 5, the number of transformation products and the reaction times required for achieving complete oxidation were greater in sludge than in the treated effluent; meanwhile, at pH 7 and 9, the number of transformation products and reaction times needed for non-detection were of the same order in both the treated effluent and the sludge. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Spatiotemporal Variation on Water Quality and Trophic State of a Tropical Urban Reservoir: A Case Study of the Lake Paranoá-DF, Brazil
Water 2021, 13(22), 3314; https://doi.org/10.3390/w13223314 - 22 Nov 2021
Viewed by 574
Abstract
Nutrient enrichment and eutrophication are among the main problems that lead to the deterioration of water quality in lakes and reservoirs. In this study, spatial and temporal variations in the concentrations of organic and inorganic species of nitrogen and phosphorus in the water [...] Read more.
Nutrient enrichment and eutrophication are among the main problems that lead to the deterioration of water quality in lakes and reservoirs. In this study, spatial and temporal variations in the concentrations of organic and inorganic species of nitrogen and phosphorus in the water column of Lake Paranoá-DF (Brazil) were evaluated between 2016 and 2017. Seasonality was the main factor in the variations in concentrations of the investigated parameters. Additionally, we found differences in behavior for different nutrients and other variables that indicate different main sources of each nutrient as well as different biogeochemical processes predominating in each season. For example, the electrical conductivity (EC), dissolved silicon, PO43, and NO3 showed mean concentrations significantly higher in the rainy season, indicating greater inputs in these periods (which is in part related to increasing soil leaching and runoff). Agricultural activities were the main source of NO3 and wastewater treatment plants (WWTP) proved to be the main source of nutrients, mainly NH4+ and all forms of phosphorus. These two allochthonous sources are also the determining factors of the trophic state and the degradation of the water quality of Lake Paranoá. The lake is in the transition process from a mesotrophic to a eutrophic condition. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Reduction of COD and Highly Coloured Mature Landfill Leachate by Tin Tetrachloride with Rubber Seed and Polyacrylamide
Water 2021, 13(21), 3062; https://doi.org/10.3390/w13213062 - 02 Nov 2021
Cited by 2 | Viewed by 562
Abstract
Tin tetrachloride (SnCl4) as a coagulant and rubber seed (Hevea brasiliensis) (RS), and polyacrylamide (PAM) as the coagulant aid were investigated in this work to treat matured and stabilised landfill leachate rich in COD and colour. A standard jar [...] Read more.
Tin tetrachloride (SnCl4) as a coagulant and rubber seed (Hevea brasiliensis) (RS), and polyacrylamide (PAM) as the coagulant aid were investigated in this work to treat matured and stabilised landfill leachate rich in COD and colour. A standard jar test was conducted at different pH values and dosages of coagulant/coagulant aid. When SnCl4 acted as the primary coagulant, the optimum conditions occurred at pH 8 and 10,000 mg/L dosages, with 97.3% and 81% reductions of colour and COD, respectively. Both RS and PAM were not effective when used alone. When RS was used as the coagulant aid, the dosage of SnCl4 was reduced to 8000 mg/L. The colour reduction was maintained at 97.6%, but the COD removal dropped to 43.1%. In comparison, when PAM was supplemented into 6000 mg/L SnCl4, the reduction in colour was maintained at 97.6%, and the COD removal was almost at par when SnCl4 was used alone. The addition of polymers as the coagulant aid helped in improving the sludge properties with a better settling rate (SSR) and larger flocs size. The decline of the SVI value indicates that less amount of sludge will be disposed of after the treatment. In addition, the rise of settling velocity (SSR) will reduce the size of the settling tank used in coagulation-flocculation treatment. Based on the results, it can be concluded that incorporation of coagulant aid into the treatment reduced the primary coagulant dosage without affecting the removal performances of pollutants. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Article
Enhancement of Power Generation and Organic Removal in Double Anode Chamber Designed Dual-Chamber Microbial Fuel Cell (DAC-DCMFC)
Water 2021, 13(21), 2941; https://doi.org/10.3390/w13212941 - 20 Oct 2021
Cited by 1 | Viewed by 1212
Abstract
One of the important factors in enhancing the performance of microbial fuel cells (MFCs) is reactor design and configuration. Therefore, this study was conducted to evaluate the regressors and their operating parameters affecting the double anode chamber–designed dual-chamber microbial fuel cell (DAC-DCMFC) performance. [...] Read more.
One of the important factors in enhancing the performance of microbial fuel cells (MFCs) is reactor design and configuration. Therefore, this study was conducted to evaluate the regressors and their operating parameters affecting the double anode chamber–designed dual-chamber microbial fuel cell (DAC-DCMFC) performance. Its primary design consists of two anode chamber compartments equipped with a separator and cathode chamber. The DAC-DCMFCs were parallelly operated over 8 days (60 days after the acclimation period). They were intermittently pump-fed with the different organic loading rates (OLRs), using chemically enriched sucrose as artificial wastewater. The applied OLRs were adjusted at low, medium, and high ranges from 0.4 kg.m−3.d−1 to 2.5 kg.m−3.d−1. The reactor types were type 1 and type 2 with different cathode materials. The pH, temperature, oxidation-reduction potential (ORP), optical density 600 (OD600), chemical oxygen demand (COD), and total organic carbon (TOC) were measured, using standard analytical instruments. In general, the power production achieved a maximum of 866 ± 44 mW/m2, with a volumetric power density of 5.15 ± 0.26 W/m3 and coulombic efficiency of 84%. Two-stage COD and TOC removal at medium OLR achieved a range of 60–80%. Medium OLR is the recommended level to enhance power production and organic removal in DAC-DCMFC. The separated anode chambers into two parts in a dual anode chamber microbial fuel cell adjusted by various organic loadings expressed a preferable comprehension in the integrated MFCs for wastewater treatment. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Communication
Removal of Coliphage MS2 Using a Microbial Fuel Cell Stack
Water 2021, 13(19), 2756; https://doi.org/10.3390/w13192756 - 05 Oct 2021
Viewed by 493
Abstract
Bioelectrochemical technologies offer alternative ways of treating wastewater and using this process to generate electricity. However, research in this area is just beginning to consider environmental transmission of viruses present in wastewater. The viral fecal indicator coliphage MS2 (the most frequently used pathogen [...] Read more.
Bioelectrochemical technologies offer alternative ways of treating wastewater and using this process to generate electricity. However, research in this area is just beginning to consider environmental transmission of viruses present in wastewater. The viral fecal indicator coliphage MS2 (the most frequently used pathogen model) was used in this study, since it is a well-known indigenous wastewater virus. The scaled-up bioelectrochemical system had a working volume of 167 L and coliphage MS2 concentration decreased from 8000 to 285 PFU/mL. The kinetics were quantified up to 15 h, after which excessive yeast growth in the system prevented further bacteriophage determination. The logarithmic reduction value (LRV) calculated within the first three hours was 3.8. From 4 hours to 14, LRV values were from 4.1 to 4.8, and in hour 15 the LRV increased to 5.3, yielding a more than 90% reduction. Overall, results obtained indicate that the scaled-up bioelectrochemical treatment system was efficient in reducing coliphage MS2 densities and could be used as a model to explore its further applicability for the reduction of viruses or pathogens in treated effluents. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Review

Jump to: Research

Review
IoT-Based Solutions to Monitor Water Level, Leakage, and Motor Control for Smart Water Tanks
Water 2022, 14(3), 309; https://doi.org/10.3390/w14030309 - 20 Jan 2022
Cited by 2 | Viewed by 1375
Abstract
Today, a large portion of the human population around the globe has no access to freshwater for drinking, cooking, and other domestic applications. Water resources in numerous countries are becoming scarce due to over urbanization, rapid industrial growth, and current global warming. Water [...] Read more.
Today, a large portion of the human population around the globe has no access to freshwater for drinking, cooking, and other domestic applications. Water resources in numerous countries are becoming scarce due to over urbanization, rapid industrial growth, and current global warming. Water is often stored in the aboveground or underground tanks. In developing countries, these tanks are maintained manually, and in some cases, water is wasted due to human negligence. In addition, water could also leak out from tanks and supply pipes due to the decayed infrastructure. To address these issues, researchers worldwide turned to the Internet-of-Things (IoT) technology to efficiently monitor water levels, detect leakage, and auto refill tanks whenever needed. Notably, this technology can also supply real-time feedback to end-users and other experts through a webpage or a smartphone. Literature reveals a plethora of review articles on smart water monitoring, including water quality, supply pipes leakage, and water waste recycling. However, none of the reviews focus on the IoT-based solution to monitor water level, detect water leakage, and auto control water pumps, especially at the induvial level that form a vast proportion of water consumers worldwide. To fill this gap in the literature, this study presents a review of IoT-controlled water storage tanks (IoT-WST). Some important contributions of our work include surveying contemporary work on IoT-WST, elaborating current techniques and technologies in IoT-WST, targeting proper hardware, and selecting a secure IoT cloud server. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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Review
Applications of Nano-Zeolite in Wastewater Treatment: An Overview
Water 2022, 14(2), 137; https://doi.org/10.3390/w14020137 - 06 Jan 2022
Cited by 2 | Viewed by 761
Abstract
Nano-zeolite is an innovative class of materials that received recognition for its potential use in water and tertiary wastewater treatment. These applications include ion-exchange/sorption, photo-degradation, and membrane separation. The aim of this work is to summarize and analyze the current knowledge about the [...] Read more.
Nano-zeolite is an innovative class of materials that received recognition for its potential use in water and tertiary wastewater treatment. These applications include ion-exchange/sorption, photo-degradation, and membrane separation. The aim of this work is to summarize and analyze the current knowledge about the utilization of nano-zeolite in these applications, identify the gaps in this field, and highlight the challenges that face the wide scale applications of these materials. Within this context, an introduction to water quality, water and wastewater treatment, utilization of zeolite in contaminant removal from water was addressed and linked to its structure and the advances in zeolite preparation techniques were overviewed. To have insights into the trends of the scientific interest in this field, an in-depth analysis of the variation in annual research distribution over the last decade was performed for each application. This analysis covered the research that addressed the potential use of both zeolites and nano-zeolites. For each application, the characterization, experimental testing schemes, and theoretical analysis methodologies were overviewed. The results of the most advanced research were collected, summarized, and analyzed to allow an easy visualization and comparison of these research results. Finally, the gaps and challenges that face these applications are concluded. Full article
(This article belongs to the Special Issue Water Quality Engineering and Wastewater Treatment Ⅱ)
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