Applied Sciences

Editorial

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2 pages, 158 KiB

Open AccessEditorial

Special Issue on Wastewater Treatment Technologies

by Jaecheul Yu

Appl. Sci. 2022, 12(13), 6504; https://doi.org/10.3390/app12136504 - 27 Jun 2022

Cited by 1 | Viewed by 2640

Abstract

Wastewater treatment technology has a history spanning thousands of years, while the activated sludge process is only 100 years old [...] Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

Research

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12 pages, 1897 KiB

Open AccessArticle

Advanced Oxidation Pretreatment for Biological Treatment of Reclaimer Wastewater Containing High Concentration N-methyldiethanolamine

by Gi-Taek Oh, Chi-Kyu Ahn and Min-Woo Lee

Appl. Sci. 2022, 12(8), 3960; https://doi.org/10.3390/app12083960 - 14 Apr 2022

Cited by 4 | Viewed by 1715

Abstract

A wastewater treatment configuration consisting of advanced oxidation pretreatment and biological wastewater treatment process (BWTP) was investigated to treat a reclaimer wastewater generated in a steel-making industry, which contained high concentration MDEA (N-methyldiethanolamine) of up to 20,548 mg/L and other pollutants [...] Read more.

A wastewater treatment configuration consisting of advanced oxidation pretreatment and biological wastewater treatment process (BWTP) was investigated to treat a reclaimer wastewater generated in a steel-making industry, which contained high concentration MDEA (N-methyldiethanolamine) of up to 20,548 mg/L and other pollutants such as formate, phenol, and thiocyanate. The Fenton, ozone, and peroxone methods were tested as candidates, and the peroxone method was chosen because it could selectively decompose MDEA resulting in the final MDEA and chemical oxygen demand (COD) removal efficiencies of 92.87% and 27.16%, respectively. Through the respirometer tests using the sludge of the BWTP, it was identified that the microbial toxicity of the peroxone-pretreated wastewater was negligible and the short-term biochemical oxygen demand (BOD) to COD ratio, indicating that the biodegradability of wastewater significantly increased from 0.103 to 0.147 by the peroxone pretreatment. Analysis of the oxygen uptake rate profiles also revealed that the microbial degradation rate of the pollutants present in the reclaimer wastewater was in the order of phenol > formate > thiocyanate > MDEA, which could be changed depending on the microbial community structure of the BWTP. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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8 pages, 1815 KiB

Open AccessArticle

A Simple Analysis Method of Specific Anammox Activity Using a Respirometer

by Jaecheul Yu, Yeonju Kim, Jeongmi Kim, Soyeon Jeong, Seongjae Park and Taeho Lee

Appl. Sci. 2022, 12(3), 1121; https://doi.org/10.3390/app12031121 - 21 Jan 2022

Cited by 4 | Viewed by 1987

Abstract

Anaerobic ammonium oxidation (anammox) is a biological nitrogen removal process with attractive prospects, such as no carbon addition, less aeration, lower greenhouse gas generation, and lower sludge production. However, it is difficult to maintain a stable anammox process since the anammox bacteria have [...] Read more.

Anaerobic ammonium oxidation (anammox) is a biological nitrogen removal process with attractive prospects, such as no carbon addition, less aeration, lower greenhouse gas generation, and lower sludge production. However, it is difficult to maintain a stable anammox process since the anammox bacteria have a slow growth rate and high sensitivity to many factors. Therefore, it is very important to analyze and maintain the anammox activity as a process indicator for its successful operation. The conventional method for measuring the concentration of nitrogen compounds, such as ammonium, nitrite, or nitrogen gas is inconvenient during the reaction time for specific anammox activity (SAA) analysis, which can result in an inaccurately determined SAA due to the substrate loss and temperature change. In this study, a respirometer was utilized to analyze the SAA. The SAA values from a respirometer (rSAA) showed a similar pattern to the SAA values (mSAA) from the conventional method. All of the SAA analyses showed the highest value at 35 °C with a granule size of <1 mm. Statistical analysis showed no significant differences regardless of the analysis method, since the p-values for the t-test and Wilcoxon rank-sum test were >0.05. Therefore, the respirometer can be used as a simple and efficient tool for SAA analysis. Moreover, the operating maintenance and management of the anammox process can be improved due to the simple SAA analysis in the field. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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15 pages, 3969 KiB

Open AccessArticle

Differences in the Effects of Calcium and Magnesium Ions on the Anammox Granular Properties to Alleviate Salinity Stress

by Yeonju Kim, Jaecheul Yu, Soyeon Jeong, Jeongmi Kim, Seongjae Park, Hyokwan Bae, Sung-Keun Rhee, Tatsuya Unno, Shou-Qing Ni and Taeho Lee

Appl. Sci. 2022, 12(1), 19; https://doi.org/10.3390/app12010019 - 21 Dec 2021

Cited by 11 | Viewed by 2522

Abstract

Divalent cations were known to alleviate salinity stress on anammox bacteria. Understanding the mechanism of reducing the salinity stress on anammox granules is essential for the application of the anammox process for saline wastewater treatment. In this study, the effect of Ca²⁺ [...] Read more.

Divalent cations were known to alleviate salinity stress on anammox bacteria. Understanding the mechanism of reducing the salinity stress on anammox granules is essential for the application of the anammox process for saline wastewater treatment. In this study, the effect of Ca²⁺ and Mg²⁺ augmentation on the recovery of the activity of freshwater anammox granules affected by salinity stress was evaluated. At the condition of a salinity stress of 5 g NaCl/L, the specific anammox activity (SAA) of the granule decreased to 50% of that of the SAA without NaCl treatment. Augmentation of Ca²⁺ at the optimum concentration of 200 mg/L increased the SAA up to 78% of the original activity, while the augmentation of Mg²⁺ at the optimum concentration of 70 mg/L increased the SAA up to 71%. EPS production in the granules was increased by the augmentation of divalent cations compared with the granules affected by salinity stress. In the soluble EPS, the ratio of protein to polysaccharides was higher in the granules augmented by Ca²⁺ than with Mg²⁺, and the functional groups of the EPS differed from each other. The amount of Na⁺ sequestered in the soluble EPS was increased by the augmentation of divalent cations, which seems to contribute to the alleviation of salinity stress. Ca. Kuenenia-like anammox bacteria, which were known to be salinity stress-tolerant, were predominant in the granules and there was no significant difference in the microbial community of the granules by the salinity stress treatment. Our results suggest that the alleviation effect of the divalent cations on the salinity stress on the anammox granules might be associated with the increased production of different EPS rather than in changes to the anammox bacteria. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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18 pages, 2871 KiB

Open AccessFeature PaperArticle

Mathematical Tool Based on Breakthrough Curves to Evaluate the Economic Advantages of Chemical Regeneration of Activated Carbon in Power Plants: A Comparative Study

by Thayset Mariño Peacok, Harold Crespo Sariol, Jeamichel Puente Torres, Jan Yperman, Ángel Sánchez Roca, Robert Carleer and Liset Salomón García

Appl. Sci. 2021, 11(24), 11786; https://doi.org/10.3390/app112411786 - 11 Dec 2021

Cited by 4 | Viewed by 1943

Abstract

A mathematical tool has been developed to evaluate the economic advantages of in-situ chemical regeneration of fixed-bed industrial adsorbers of granular activated carbon for cooling water treatment systems in Cuban power plants. Two scenarios of activated carbon (AC) management in a power plant [...] Read more.

A mathematical tool has been developed to evaluate the economic advantages of in-situ chemical regeneration of fixed-bed industrial adsorbers of granular activated carbon for cooling water treatment systems in Cuban power plants. Two scenarios of activated carbon (AC) management in a power plant were compared by applying the proposed model. The economic profit by implementing the regeneration strategy as a function of the number of regeneration cycles was determined and optimized. Breakthrough curves were obtained to assess the adsorption performance of the AC after progressive saturation–chemical regeneration cycles using synthetic water and hydrochloric acid, respectively. For the first saturation cycle, the breakthrough time was 272 min and after 10 cycles, it was reduced to 58 min, indicating a decrease of the adsorption capacity of 21%. The AC adsorption performance in terms of saturation time as a function of the number of regeneration cycles was considered one of the tool parameters. The proposed tool allows to determine the optimal number of regeneration cycles for a maximum economic profit in the regeneration strategy. It was demonstrated, using the proposed tool, that after an optimum of seven regeneration cycles, the power plant expends only 26% of the total investment. The simplicity of the tool permits a rapid way to find the most profitable number of regeneration cycles by combining economic, technical and adsorption efficiency parameters in one function, thus improving the AC management strategy at an industrial scale with corresponding environmental and economic advantages, including sustainability. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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22 pages, 20865 KiB

Open AccessFeature PaperArticle

Recovery of Heavy Metal Ions Using Magnetic Glycine-Modified Chitosan—Application to Aqueous Solutions and Tailing Leachate

by Asmaa Benettayeb, Amine Morsli, Khalid Z. Elwakeel, Mohammed F. Hamza and Eric Guibal

Appl. Sci. 2021, 11(18), 8377; https://doi.org/10.3390/app11188377 - 9 Sep 2021

Cited by 46 | Viewed by 2656

Abstract

The necessity of decontaminating effluents for the dual purpose of environmental beneficiation and valorization of low-grade resources is driving the development of new sorbents. The functionalization of biopolymers is a promising strategy for improving sorption performance. Incorporating magnetic micro-particles offers an opportunity for [...] Read more.

The necessity of decontaminating effluents for the dual purpose of environmental beneficiation and valorization of low-grade resources is driving the development of new sorbents. The functionalization of biopolymers is a promising strategy for improving sorption performance. Incorporating magnetic micro-particles offers an opportunity for the facilitated recovery of spent micron-size sorbent. Combining magnetic facilities and biopolymer functionalization represents a winning strategy. Magnetic glycine-grafted chitosan (G@MChs) was synthesized for the sorption of Ni(II), Zn(II), and Hg(II) before being applied to the removal of hazardous and strategic metals from tailing leachates. The sorbent was characterized using Fourier transform infrared spectroscopy and scanning electron microscopy, before and after metal sorption. The acid–base properties of functionalized sorbent were also determined (pH_PZC). Uptake kinetics were studied in mono- and multi-component solutions using different equations for kinetic modeling at optimized pH (i.e., pH₀: 5.5). Langmuir and Sips equations were applied to model sorption isotherms in single-component solutions. In addition, sorption isotherms in multi-component solutions were used to evaluate the preference for selected metals. Maximum sorption capacities were 0.35 mmol Hg g⁻¹, 0.47 mmol Zn g⁻¹, and 0.50 mmol Ni g⁻¹. Acidified urea solution (pH 2.7) successfully desorbs metal ions from G@MChs (desorption > 90%). The sorbent was tested for the recovery of hazardous and strategic metal ions from acidic leachates of tailings. This study demonstrates the promising performance of G@MChs for the treatment of complex metal-bearing solutions. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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14 pages, 2575 KiB

Open AccessArticle

Modeling of the Suspended Solid Removal of a Granular Media Layer in an Upflow Stormwater Runoff Filtration System

by Yuhoon Hwang, Younggyo Seo, Seokoh Ko and Dogun Kim

Appl. Sci. 2021, 11(13), 6202; https://doi.org/10.3390/app11136202 - 4 Jul 2021

Cited by 2 | Viewed by 2063

Abstract

Upflow granular media filtration devices are widely used for stormwater runoff treatment. However, the system performance is not well characterized due to the irregular removal of suspended solid (SS) in the pretreatment (sedimentation) chamber and, hence, its irregular input to the media layer. [...] Read more.

Upflow granular media filtration devices are widely used for stormwater runoff treatment. However, the system performance is not well characterized due to the irregular removal of suspended solid (SS) in the pretreatment (sedimentation) chamber and, hence, its irregular input to the media layer. In this regard, the performance of the granular media layer of an upflow filtration system is investigated herein by the use of various models. Due to the significant variation in the SS concentration of the influent and effluent to and from the media layer, the deep bed filtration model, the k-C* model, and the porous media capture model provide limited descriptions of the system performance. By contrast, the performance is well described using the kinetic model, the modified k-C* model using a specific deposit, and the modified porous media capture model using a specific deposit. The parameters of the latter models are shown to be in good correlation with the filtration velocity, SS removal, and specific deposit. The results suggest that modeling using a specific SS deposit can provide an accurate description of the granular media layer performance under a highly variable influent SS concentration. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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10 pages, 1577 KiB

Open AccessArticle

Effects of a Hydraulic Series Connection and Flow Direction on Electricity Generation in a Stack Connected with Different Volume MFCs

by Jaecheul Yu

Appl. Sci. 2021, 11(3), 1019; https://doi.org/10.3390/app11031019 - 23 Jan 2021

Cited by 5 | Viewed by 1400

Abstract

Three microbial fuel cells (MFCs) with different volumes (S-, M-, and L-MFCs) were operated at individual flow (phase I) and serially connected flow modes (phase II for forward flow and phase III for reverse flow) at the same flow rate. The three MFCs [...] Read more.

Three microbial fuel cells (MFCs) with different volumes (S-, M-, and L-MFCs) were operated at individual flow (phase I) and serially connected flow modes (phase II for forward flow and phase III for reverse flow) at the same flow rate. The three MFCs showed different voltages and power generation according to the hydraulic and electric connection modes. The M- and L-MFCs showed a similar voltage at hydraulic series-forward flow mode (phase II). The principal component analysis (PCA) and Pearson correlation showed that voltage generation and power density were affected by volume, hydraulic retention time (HRT), chemical oxygen demand (COD) loading rate, removed COD, and internal resistances. When they were connected electrically in series and parallel, the stack showed relatively lower voltage loss (28–30%) compared to the voltage losses of the other stacks (43–94%). These results suggest an easy way to connect MFCs with different volumes can be a new option to avoid voltage reversal and minimize energy loss. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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Review

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14 pages, 2875 KiB

Open AccessReview

The Role of Wetland Plants on Wastewater Treatment and Electricity Generation in Constructed Wetland Coupled with Microbial Fuel Cell

by Ke Li, Jingyao Qi, Fuguo Zhang, Nicholas Miwornunyuie, Paulette Serwaa Amaniampong, Desmond Ato Koomson, Lei Chen, Yu Yan, Yanhong Dong, Victor Edem Setordjie and Abigail Mwin-nea Samwini

Appl. Sci. 2021, 11(16), 7454; https://doi.org/10.3390/app11167454 - 13 Aug 2021

Cited by 12 | Viewed by 3577

Abstract

CWMFC is a novel technology that has been used for almost a decade for concurrent wastewater treatment and electricity generation in varying scopes of domestic, municipal, and industrial applications since its implementation in 2012. Its advantage of low-cost enhanced wastewater treatment and sustainable [...] Read more.

CWMFC is a novel technology that has been used for almost a decade for concurrent wastewater treatment and electricity generation in varying scopes of domestic, municipal, and industrial applications since its implementation in 2012. Its advantage of low-cost enhanced wastewater treatment and sustainable bioelectricity generation has gained considerable attention. Nevertheless, the overall efficiency of this novel technology is inclined by several operating factors and configuration strands, such as pH, sewage composition, organic loading, electrode material, filter media, electrogens, hydraulic retention time, and macrophytes. Here, we investigate the effect of the wetland plant component on the overall performance of CWMFCs. The macrophyte’s involvement in the oxygen input, nutrient uptake, and direct degradation of pollutants for the required treatment effect and bioelectricity production are discussed in more detail. The review identifies and compares planted and unplanted CWMFC with their efficiency on COD removal and electricity generation based on previous and recent studies. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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18 pages, 615 KiB

Open AccessReview

Marine Actinobacteria Bioflocculant: A Storehouse of Unique Biotechnological Resources for Wastewater Treatment and Other Applications

by Oluyemi Olatunji Awolusi, Adedeji Nelson Ademakinwa, Abidemi Ojo, Mariana Erasmus, Faizal Bux and Mayowa Oladele Agunbiade

Appl. Sci. 2020, 10(21), 7671; https://doi.org/10.3390/app10217671 - 30 Oct 2020

Cited by 8 | Viewed by 3300

Abstract

The bioactive compounds produced by actinobacteria have played a major role in antimicrobials, bioremediation, biofuels, enzymes, and anti-cancer activities. Biodegradable microbial flocculants have been produced by bacteria, algae, and fungi. Microbial bioflocculants have also attracted biotechnology importance over chemical flocculants as a result [...] Read more.

The bioactive compounds produced by actinobacteria have played a major role in antimicrobials, bioremediation, biofuels, enzymes, and anti-cancer activities. Biodegradable microbial flocculants have been produced by bacteria, algae, and fungi. Microbial bioflocculants have also attracted biotechnology importance over chemical flocculants as a result of degradability and environmentally friendly attributes they possess. Though, freshwater actinobacteria flocculants have been explored in bioflocculation. Yet, there is a paucity of information on the application of actinobacteria flocculants isolated from the marine environment. Similarly, marine habitats that supported the biodiversity of actinobacteria strains in the field of biotechnology have been underexplored in bioflocculation. Hence, this review reiterates the need to optimize culture conditions and other parameters that affect bioflocculant production by using a response surface model or artificial neural network. Full article

(This article belongs to the Special Issue Wastewater Treatment Technologies)

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