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To date, energy recovery from biological sewage sludge (BSS) by anaerobic digestion has been very popular. However, it can often happen that anaerobic reactors are volumetrically undersized, thus reducing performance in terms of biogas production. A continuous-flow pilot-scale plant was used to investigate, for the first time, the effects of mesophilic anaerobic co-digestion (MACoD) of sewage sludge and aqueous residue (AR) from a biosolids treatment plant (BTP) on methanogenic activity under low hydraulic retention time (HRT) conditions (to simulate the undersizing of the reactor). The results showed that the digestate is always more rapidly biodegradable than the matrices fed, while particulate COD hydrolyzed (12 ± 1.3%) is independent of the quantity of AR dosed. Feeding over 35% of soluble OLR, the total VFAs in the system strongly decreased, despite the low HRT. In correspondence with higher dosages of AR, the percentage of CH4 increased up to 77–78% and the CO2 CH4−1 ratio decreased to 0.25 ± 0.2. Specific methane production increased from 0.09 ± 0.01 m3CH4 kgCODremoved−1 with BSS alone to 0.28 ± 0.01 m3CH4CH4 kgCODremoved−1 in the case of BSS co-digested with AR. Moreover, co-digestion with AR from a BTP allowed continuous specific methanogenic activity to be enhanced from 1.76 ± 0.02 m3CH4 tVSS−1 d−1 to 6.48 ± 0.88 m3CH4 tVSS−1 d−1. Therefore, the MACoD of BSS and AR from a BTP could be a good solution to enhance methanogenic activity in a volumetrically undersized anaerobic digester with reduced HRT.
Vincenzo Torretta; Athanasia Tolkou; Ioannis Katsoyiannis; Francesca Caccamo; Marco Miino; Marco Baldi; Maria Collivignarelli. Enhancement of Methanogenic Activity in Volumetrically Undersized Reactor by Mesophilic Co-Digestion of Sewage Sludge and Aqueous Residue. Sustainability 2021, 13, 7728 .
AMA StyleVincenzo Torretta, Athanasia Tolkou, Ioannis Katsoyiannis, Francesca Caccamo, Marco Miino, Marco Baldi, Maria Collivignarelli. Enhancement of Methanogenic Activity in Volumetrically Undersized Reactor by Mesophilic Co-Digestion of Sewage Sludge and Aqueous Residue. Sustainability. 2021; 13 (14):7728.
Chicago/Turabian StyleVincenzo Torretta; Athanasia Tolkou; Ioannis Katsoyiannis; Francesca Caccamo; Marco Miino; Marco Baldi; Maria Collivignarelli. 2021. "Enhancement of Methanogenic Activity in Volumetrically Undersized Reactor by Mesophilic Co-Digestion of Sewage Sludge and Aqueous Residue." Sustainability 13, no. 14: 7728.
In recent years, there has been an increase in public perception of the detrimental side-effects of fluoride to human health due to its effects on teeth and bones. Today, there is a plethora of techniques available for the removal of fluoride from drinking water. Among them, adsorption is a very prospective method because of its handy operation, cost efficiency, and high selectivity. Along with efforts to assist fluoride removal from drinking waters, extensive attention has been also paid to the accurate measurement of fluoride in water. Currently, the analytical methods that are used for fluoride determination can be classified into chromatographic methods (e.g., ionic chromatography), electrochemical methods (e.g., voltammetry, potentiometry, and polarography), spectroscopic methods (e.g., molecular absorption spectrometry), microfluidic analysis (e.g., flow injection analysis and sequential injection analysis), titration, and sensors. In this review article, we discuss the available techniques and the ongoing effort for achieving enhanced fluoride removal by applying novel adsorbents such as carbon-based materials (i.e., activated carbon, graphene oxide, and carbon nanotubes) and nanostructured materials, combining metals and their oxides or hydroxides as well as natural materials. Emphasis has been given to the use of lanthanum (La) in the modification of materials, both activated carbon and hybrid materials (i.e., La/Mg/Si-AC, La/MA, LaFeO3 NPs), and in the use of MgO nanostructures, which are found to exhibit an adsorption capacity of up to 29,131 mg g−1. The existing analytical methodologies and the current trends in analytical chemistry for fluoride determination in drinking water are also discussed.
Athanasia Tolkou; Natalia Manousi; George Zachariadis; Ioannis Katsoyiannis; Eleni Deliyanni. Recently Developed Adsorbing Materials for Fluoride Removal from Water and Fluoride Analytical Determination Techniques: A Review. Sustainability 2021, 13, 7061 .
AMA StyleAthanasia Tolkou, Natalia Manousi, George Zachariadis, Ioannis Katsoyiannis, Eleni Deliyanni. Recently Developed Adsorbing Materials for Fluoride Removal from Water and Fluoride Analytical Determination Techniques: A Review. Sustainability. 2021; 13 (13):7061.
Chicago/Turabian StyleAthanasia Tolkou; Natalia Manousi; George Zachariadis; Ioannis Katsoyiannis; Eleni Deliyanni. 2021. "Recently Developed Adsorbing Materials for Fluoride Removal from Water and Fluoride Analytical Determination Techniques: A Review." Sustainability 13, no. 13: 7061.
Dyes are known as one of the most dangerous industrial pollutants which can cause skin diseases, allergy, and provoke cancer and mutation in humans. Therefore, one of the important environmental issues is the effective removal of dyes from industrial wastewater. In the current work, BaFe12O19/[email protected] glycol (abbreviated as BFO/[email protected]) nanocomposite was synthesized and evaluated regarding its capacity for adsorptive removal of a model dye Acid Blue 92 (denoted as AB92) from aqueous solutions. The characteristics of the prepared nanocomposite was determined by tests such as X-ray diffraction (XRD), scanning electron microscope (SEM), vibration sample magnetization (VSM), and Fourier transform infrared spectroscopy (FTIR). The effects of conditional parameters including pH (2–12), initial concentration of dye (20–100 mg/L), adsorbent dosage (0.02–0.1 g/L) and contact time (0-180 min) on the adsorption of dye were investigated and then optimized. The results indicated that with the increase of the adsorbent dosage from 0.02 to 0.1 g/L, the removal efficiency increased from 74.1% to 78.6%, and the adsorbed amount decreased from 148.25 to 31.44 mg/g. The maximum removal efficiency (77.54%) and adsorption capacity (31.02 mg/g) were observed at pH 2. Therefore, the general optimization conditions revealed that the maximum adsorption efficiency of dye was obtained in condition of initial concentration of 20 mg/L, contact time of 1 h and pH of solution equal 2. The adsorption isotherm and kinetic data were evaluated using a series of models. The pseudo-second order kinetic model and Freundlich isotherm model show the best fitting with experimental data with R2∼0.999.
Somayeh Rahdar; Abbas Rahdar; Mostafa Sattari; Laleh Hafshejani; Athanasia Tolkou; George Kyzas. Barium/[email protected] Glycol Nanocomposites for Dye Removal from Aqueous Solutions. Polymers 2021, 13, 1161 .
AMA StyleSomayeh Rahdar, Abbas Rahdar, Mostafa Sattari, Laleh Hafshejani, Athanasia Tolkou, George Kyzas. Barium/[email protected] Glycol Nanocomposites for Dye Removal from Aqueous Solutions. Polymers. 2021; 13 (7):1161.
Chicago/Turabian StyleSomayeh Rahdar; Abbas Rahdar; Mostafa Sattari; Laleh Hafshejani; Athanasia Tolkou; George Kyzas. 2021. "Barium/[email protected] Glycol Nanocomposites for Dye Removal from Aqueous Solutions." Polymers 13, no. 7: 1161.
This review is an update about the addition of nanomaterials in cementitious composites in order to improve their performance. The most common used nanomaterials for cementitious materials are carbon nanotubes, nanocellulose, nanographene, graphene oxide, nanosilica and nanoTiO2. All these nanomaterials can improve the physical, mechanical, thermal and electrical properties of cementitious composites, for example increase their compressive and tensile strength, accelerate hydration, decrease porosity and enhance fire resistance. Cement based materials have a very complex nanostructure consisting of hydration products, crystals, unhydrated cement particles and nanoporosity where traditional reinforcement, which is at the macro and micro scale, is not effective. Nanomaterials can reinforce the nanoscale, which wasn’t possible heretofore, enhancing the performance of the cementitious matrix.
Zoi Metaxa; Athanasia Tolkou; Stefania Efstathiou; Abbas Rahdar; Evangelos Favvas; Athanasios Mitropoulos; George Kyzas. Nanomaterials in Cementitious Composites: An Update. Molecules 2021, 26, 1430 .
AMA StyleZoi Metaxa, Athanasia Tolkou, Stefania Efstathiou, Abbas Rahdar, Evangelos Favvas, Athanasios Mitropoulos, George Kyzas. Nanomaterials in Cementitious Composites: An Update. Molecules. 2021; 26 (5):1430.
Chicago/Turabian StyleZoi Metaxa; Athanasia Tolkou; Stefania Efstathiou; Abbas Rahdar; Evangelos Favvas; Athanasios Mitropoulos; George Kyzas. 2021. "Nanomaterials in Cementitious Composites: An Update." Molecules 26, no. 5: 1430.
This study presents for the first time the synthesis and characterization of GO (graphene oxide), PFSiC (polyferric silicate chloride), and hybrid GO-PFSiC derivatives, aiming to enhance synergistically the performance of coagulation, when applied for the treatment of water. The structure and the morphology of composite GO-PFSiC coagulants were studied in detail by the application of FTIR, XRD, and SEM characterization techniques. Furthermore, the proposed coagulants were applied for the treatment of simulated turbid surface water. The effects of the reagent’s dosage, pH value, and experimental/operational conditions on the coagulation efficiency, applied mainly for the removal of turbidity, were examined. The results, obtained from the FTIR and XRD measurements, showed the presence of a bond between the PFSiC and the GO surface, indicating that the PFSiC particles are distributed uniformly on the surface of graphene, which was also confirmed by the SEM images. Especially, the composite compound GO-PFSiC1.5-15-0.5 presents the most uniform distribution of iron on the surface of graphene oxide and exhibits the optimum coagulation efficiency, while it significantly reduces the turbidity for doses above 3–5 mg/L, i.e., achieving the respective legislation limit as proposed by WHO. Specifically, at the alkaline pH values (>7.9), the removal of turbidity reaches 96%. Consequently, the results of this study render these materials as potential coagulant agents for further research and applications, aiming to also achieve the co-removal of other water components.
Athanasia K. Tolkou; Anastasios I. Zouboulis. Graphene Oxide/Fe-Based Composite Pre-Polymerized Coagulants: Synthesis, Characterization, and Potential Application in Water Treatment. C 2020, 6, 44 .
AMA StyleAthanasia K. Tolkou, Anastasios I. Zouboulis. Graphene Oxide/Fe-Based Composite Pre-Polymerized Coagulants: Synthesis, Characterization, and Potential Application in Water Treatment. C. 2020; 6 (3):44.
Chicago/Turabian StyleAthanasia K. Tolkou; Anastasios I. Zouboulis. 2020. "Graphene Oxide/Fe-Based Composite Pre-Polymerized Coagulants: Synthesis, Characterization, and Potential Application in Water Treatment." C 6, no. 3: 44.
Groundwater is commonly used as a drinking water resource all over the world. Therefore, groundwater contamination by toxic metals is an important issue of utmost concern for public health, and several technologies are applied for their effective removal, such as coagulation, ion exchange, adsorption, and membrane applications like reverse osmosis. Adsorption is acknowledged as a simple, effective and economic technology, which has received increased interest recently, despite certain limitations regarding operational applications. The respective scientific efforts have been specifically focused on the development and implementation of novel nano-structured adsorbent materials, which may offer extensive specific surface areas, much higher than the conventional adsorbents, and hence, are expected to present higher removal efficiencies of pollutants. In this paper, the recent developments of nanomaterial applications for arsenic, chromium and uranium removal from groundwaters are critically reviewed. Particularly, the use of novel composite materials, based mainly on hybrid metallic oxide nanoparticles and on composites based on graphene oxide (GO) (i.e., graphene-based hybrids), showed promising evidences to achieve efficient removal of toxic metals from water sources, even in full scale applications.
Athanasia K. Tolkou; Ioannis A. Katsoyiannis; Anastasios I. Zouboulis. Removal of Arsenic, Chromium and Uranium from Water Sources by Novel Nanostructured Materials Including Graphene-Based Modified Adsorbents: A Mini Review of Recent Developments. Applied Sciences 2020, 10, 3241 .
AMA StyleAthanasia K. Tolkou, Ioannis A. Katsoyiannis, Anastasios I. Zouboulis. Removal of Arsenic, Chromium and Uranium from Water Sources by Novel Nanostructured Materials Including Graphene-Based Modified Adsorbents: A Mini Review of Recent Developments. Applied Sciences. 2020; 10 (9):3241.
Chicago/Turabian StyleAthanasia K. Tolkou; Ioannis A. Katsoyiannis; Anastasios I. Zouboulis. 2020. "Removal of Arsenic, Chromium and Uranium from Water Sources by Novel Nanostructured Materials Including Graphene-Based Modified Adsorbents: A Mini Review of Recent Developments." Applied Sciences 10, no. 9: 3241.
The aim of this study was the investigation of alternative pre-polymerized coagulants for the treatment of high-strength industrial wastewaters, such as those created by tanneries, or by yeast production industries. The novel inorganic composite coagulant examined in this study (as well as variations of it) was denoted as PSiFAC1.5-10-15. The contribution of a typical polyelectrolyte to improve the effectiveness of the coagulation/flocculation (C/F) process was additionally studied, either by adding it separately (i.e., as a flocculant aid) or by co-polymerizing it within the structure of inorganic coagulant (denoted as PAPEFAC1.5-10-15). It was found that the PSiFAC1.5:10:15 coagulant, either with or without the addition of polyelectrolyte, can provide better efficiency for the C/F process than the conventional coagulants. For example, the addition of 80 mg Al/L in yeast production wastewater samples resulted in a 56% reduction of COD, 40% of turbidity, and 43% of phosphates, regarding the pre-treated anaerobically wastewater samples and reduced by an extra 22%, 14%, and 38% for the pre-treated anaerobically plus aerobically wastewater samples, respectively. The residual aluminum concentration in the treated wastewaters was found to be below the legislation limit of 200 μg Al/L. The characterization of coagulants showed the relatively higher Al13 content of 51% and 43% for the cases of PSiFAC1.5-10-15 and PAPEFAC1.5-10-15, respectively, accompanied by the high zeta-potential measurements (50.5 and 39.5 mV).
Athanasia K. Tolkou; Anastasios I. Zouboulis. Application of Composite Pre-Polymerized Coagulants for the Treatment of High-Strength Industrial Wastewaters. Water 2020, 12, 1258 .
AMA StyleAthanasia K. Tolkou, Anastasios I. Zouboulis. Application of Composite Pre-Polymerized Coagulants for the Treatment of High-Strength Industrial Wastewaters. Water. 2020; 12 (5):1258.
Chicago/Turabian StyleAthanasia K. Tolkou; Anastasios I. Zouboulis. 2020. "Application of Composite Pre-Polymerized Coagulants for the Treatment of High-Strength Industrial Wastewaters." Water 12, no. 5: 1258.
Studies about the measurement of outdoor tobacco smoke (OTS) are limited to a few very recent studies. In many countries around the world, within public buildings, smoking is prohibited by law. However, these prohibitions often drive smokers to move to the border of the areas where smoking is forbidden, typically the entrances of buildings, in order to smoke. When many smokers stand outdoors near the entrances, a significant “wall” of smoke is generated. This condition exposes nonsmokers to smoke and contaminates the indoor environment too. Such a situation is amplified if the outdoor external area is covered. This paper presents a work carried out in a university campus, near building entrances, with the aim of studying the second-hand smoke (SHS) exposure in outdoor conditions. Measurements of particulate matter in specific environmental conditions are evaluated to estimate the OTS impacts on the students and the academic staff. The results showed that the exposure to tobacco can be very high and even comparable to values found when tests were carried out indoors, at the same distances from the smokers. A discussion about forbidding smoking near the entrances of public buildings is reported, including considerations about the environmental and public health concerns induced by SHS exposure and the smoking activity.
Vincenzo Torretta; Athanasia Tolkou; Ioannis Katsoyiannis; Marco Schiavon. Second-Hand Smoke Exposure Effects on Human Health: Evaluation of PM10 Concentrations in the External Areas of a University Campus. Sustainability 2020, 12, 2948 .
AMA StyleVincenzo Torretta, Athanasia Tolkou, Ioannis Katsoyiannis, Marco Schiavon. Second-Hand Smoke Exposure Effects on Human Health: Evaluation of PM10 Concentrations in the External Areas of a University Campus. Sustainability. 2020; 12 (7):2948.
Chicago/Turabian StyleVincenzo Torretta; Athanasia Tolkou; Ioannis Katsoyiannis; Marco Schiavon. 2020. "Second-Hand Smoke Exposure Effects on Human Health: Evaluation of PM10 Concentrations in the External Areas of a University Campus." Sustainability 12, no. 7: 2948.
Fluoride, an anionic pollutant, is possibly to be found in excessive concentrations especially in groundwaters and can show detrimental effects on human health, in concentrations higher than the commonly applied legislation limit of 1.5 mg/L The most commonly applied method for water de-fluoridation is performed by Al-based coagulants, which however presents some important limitations, such as the applied relatively high dosage, producing rather excessive amounts of chemical sludge. In this study, the use of novel pre-polymerized Al-based coagulants was examined, regarding their efficiency towards fluoride removal, as compared with the conventionally applied AlCl3. The novel coagulants were characterized by measuring the main physico-chemical properties, the aluminum species distribution, the zeta potential, the particles' size distribution and the produced flocs’ sizes. The results showed that the Mg-containing coagulant (PSiFAC-Mg30-10-15) was the most efficient, when applied in pH values relevant to fluoride-containing groundwaters; it was also the only coagulant, which increases its efficiency at pH values > 7. The uptake capacity of coagulants, regarding fluoride, to reach the residual/equilibrium concentration limit of 1.5 mg F/L (Q1.5-value) at the pH value 7.0 ± 0.1 were found 170, 134 and 94 mg F/g Al for the cases of PSiFAC-Mg30-10-15, AlCl3·6H2O and PSiFAC-Na1.5-10-15, respectively. Accordingly, at the pH value 7.8 ± 0.2 the Q1.5-values were found 189, 118 and 41 mg F/g Al for the same coagulants; whereas considering the residual aluminum concentration this was ranged at 15 ± 5, 25 ± 5 and 30 ± 5 μg Al/L, respectively. In addition, (beneficial) increase of residual magnesium concentration, when applying the coagulant PSiFAC-Mg30-10-15 was 15 ± 5 mg/L.
Athanasia K. Tolkou; Manassis Mitrakas; Ioannis A. Katsoyiannis; Mathias Ernst; Anastasios I. Zouboulis. Fluoride removal from water by composite Al/Fe/Si/Mg pre-polymerized coagulants: Characterization and application. Chemosphere 2019, 231, 528 -537.
AMA StyleAthanasia K. Tolkou, Manassis Mitrakas, Ioannis A. Katsoyiannis, Mathias Ernst, Anastasios I. Zouboulis. Fluoride removal from water by composite Al/Fe/Si/Mg pre-polymerized coagulants: Characterization and application. Chemosphere. 2019; 231 ():528-537.
Chicago/Turabian StyleAthanasia K. Tolkou; Manassis Mitrakas; Ioannis A. Katsoyiannis; Mathias Ernst; Anastasios I. Zouboulis. 2019. "Fluoride removal from water by composite Al/Fe/Si/Mg pre-polymerized coagulants: Characterization and application." Chemosphere 231, no. : 528-537.
The safety of high quality drinking water supply relies on the quantities to be delivered, on the complexity of the water supply systems, and on the widespread phenomena of the contamination of water bodies. These parameters indicate the need for the development of an application that will allow the quick acquisition of data on strategic management. This is requires both the analysis of factors related to the hydraulic operation of the plants and the characteristics of water quality. The present paper aims to evaluate the use of models that predict data for water quality in a distribution system. The assessment is made in order to consider the use of the model as a support tool for the management system of a supply network and to optimize the quality of the provided service. The improvement of the control system related to the operations of disinfection, in particular, in the case of long pipelines, is absolutely mandatory in order to ensure the safety of public health and respect for the environment at high levels.
Vincenzo Torretta; Athanasia K. Tolkou; Ioannis A. Katsoyiannis; Athanasios Katsoyiannis; Ettore Trulli; Elena Magaril; Elena Cristina Rada. Consumption of Free Chlorine in an Aqueduct Scheme with Low Protection: Case Study of the New Aqueduct Simbrivio-Castelli (NASC), Italy. Water 2018, 10, 127 .
AMA StyleVincenzo Torretta, Athanasia K. Tolkou, Ioannis A. Katsoyiannis, Athanasios Katsoyiannis, Ettore Trulli, Elena Magaril, Elena Cristina Rada. Consumption of Free Chlorine in an Aqueduct Scheme with Low Protection: Case Study of the New Aqueduct Simbrivio-Castelli (NASC), Italy. Water. 2018; 10 (2):127.
Chicago/Turabian StyleVincenzo Torretta; Athanasia K. Tolkou; Ioannis A. Katsoyiannis; Athanasios Katsoyiannis; Ettore Trulli; Elena Magaril; Elena Cristina Rada. 2018. "Consumption of Free Chlorine in an Aqueduct Scheme with Low Protection: Case Study of the New Aqueduct Simbrivio-Castelli (NASC), Italy." Water 10, no. 2: 127.
The presence of arsenic in water supplies is a major problem for public health and still concerns large parts of population in Southeast Asia, Latin America and Europe. Removal of arsenic is usually accomplished either by coagulation with iron salts or by adsorption with iron oxides or activated alumina. However, these materials, although very efficient for arsenic, normally do not remove other undesirable constituents from waters, such as chlorine and organo-chlorine compounds, which are the results of water chlorination. Activated carbon has this affinity for organic compounds, but does not remove arsenic efficiently. Therefore, in the present study, iron modified activated carbons are investigated as alternative sorbents for the removal of arsenic(V) from aqueous solutions. In addition, modified activated carbons with magnetic properties can easily be separated from the solutions. In the present study, a simple and efficient method was used for the preparation of magnetic Fe3(Mn2+)O4 (M:Fe and/or Mn) activated carbons. Activated carbons were impregnated with magnetic precursor solutions and then calcinated at 400 °C. The obtained carbons were characterized by X-ray diffraction (XRD), nitrogen adsorption isotherms, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), Fourier Transform Infrared Spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements. Their adsorption performance for As(V) was evaluated. The iron impregnation presented an increase in As(V) maximum adsorption capacity (Qmax) from about 4 mg g−1 for the raw carbon to 11.05 mg g−1, while Mn incorporation further increased the adsorption capacity at 19.35 mg g−1.
George P. Gallios; Athanasia K. Tolkou; Ioannis A. Katsoyiannis; Katarina Stefusova; Miroslava Vaclavikova; Eleni A. Deliyanni. Adsorption of Arsenate by Nano Scaled Activated Carbon Modified by Iron and Manganese Oxides. Sustainability 2017, 9, 1684 .
AMA StyleGeorge P. Gallios, Athanasia K. Tolkou, Ioannis A. Katsoyiannis, Katarina Stefusova, Miroslava Vaclavikova, Eleni A. Deliyanni. Adsorption of Arsenate by Nano Scaled Activated Carbon Modified by Iron and Manganese Oxides. Sustainability. 2017; 9 (10):1684.
Chicago/Turabian StyleGeorge P. Gallios; Athanasia K. Tolkou; Ioannis A. Katsoyiannis; Katarina Stefusova; Miroslava Vaclavikova; Eleni A. Deliyanni. 2017. "Adsorption of Arsenate by Nano Scaled Activated Carbon Modified by Iron and Manganese Oxides." Sustainability 9, no. 10: 1684.
In the present study, several pre-polymerized coagulants of iron and aluminum were tested for their efficiency towards As(V) and As(III) removal from water sources. The results showed that the pre-polymerized coagulants of iron, such as poly-ferric sulfate and poly-ferric silicate chloride, were very efficient for As(V) removal. With regard to As(III) removal, among all examined coagulants, including the conventional ferric chloride, only the poly-ferric sulfate (PFS) was able to reduce As(III) to concentrations below the drinking water regulation limit of 10 μg/L. In contrast, all tested composite coagulants based on aluminum were not capable of removing efficiently both species of arsenic. PFS addition in water containing 4 mM of alkalinity and 25 μg/L of As(V) and As(III) (i.e., total arsenic concentration 50 μg/L) resulted in finished water with less than 5 μg/L arsenic, only by dosing 5 mg Fe-PFS/L at pH 7, whereas, simultaneously, the residual iron concentration was found well below its drinking water regulation limit of 200 μg/L. The use of PFS could provide a viable alternative for As(III) and As(V) removal at household treatment level for application in vulnerable communities, without the need of any additional treatment, such as oxidation of As(III) to As(V).
Ioannis A. Katsoyiannis; Nikolaos M. Tzollas; Athanasia K. Tolkou; Manassis Mitrakas; Mathias Ernst; Anastasios I. Zouboulis. Use of Novel Composite Coagulants for Arsenic Removal from Waters—Experimental Insight for the Application of Polyferric Sulfate (PFS). Sustainability 2017, 9, 590 .
AMA StyleIoannis A. Katsoyiannis, Nikolaos M. Tzollas, Athanasia K. Tolkou, Manassis Mitrakas, Mathias Ernst, Anastasios I. Zouboulis. Use of Novel Composite Coagulants for Arsenic Removal from Waters—Experimental Insight for the Application of Polyferric Sulfate (PFS). Sustainability. 2017; 9 (4):590.
Chicago/Turabian StyleIoannis A. Katsoyiannis; Nikolaos M. Tzollas; Athanasia K. Tolkou; Manassis Mitrakas; Mathias Ernst; Anastasios I. Zouboulis. 2017. "Use of Novel Composite Coagulants for Arsenic Removal from Waters—Experimental Insight for the Application of Polyferric Sulfate (PFS)." Sustainability 9, no. 4: 590.
Municipal solid waste final disposal represents an environmental burden worldwide since landfilling, or open dumping, is still the preferred solution for the end of life of solid discarded materials. This study aims to review the technological innovations applied for landfill leachate treatment, taking into consideration the experiences obtained during the past years and the solutions which have been implemented. The review showed that both biological and physiochemical treatments are not able to achieve the requested water quality level, according to the limits established by regulations, whether applied in a single treatment or multiple treatments. In order to respect sustainable release limits to guarantee environmental protection, the construction of depuration systems and combining biological and physiochemical treatment methods is considered of the utmost importance. The review looks at possible joint applications of different treatment techniques reviewed by other studies and considers the state of the art of current research. Combined technical solutions suggested within the 2016 peer-reviewed papers are presented and discussed as a sustainable way to effectively treat landfill leachate, giving particular attention to feasible solutions for developing countries.
Vincenzo Torretta; Navarro Ferronato; Ioannis A. Katsoyiannis; Athanasia K. Tolkou; Michela Airoldi. Novel and Conventional Technologies for Landfill Leachates Treatment: A Review. Sustainability 2016, 9, 9 .
AMA StyleVincenzo Torretta, Navarro Ferronato, Ioannis A. Katsoyiannis, Athanasia K. Tolkou, Michela Airoldi. Novel and Conventional Technologies for Landfill Leachates Treatment: A Review. Sustainability. 2016; 9 (1):9.
Chicago/Turabian StyleVincenzo Torretta; Navarro Ferronato; Ioannis A. Katsoyiannis; Athanasia K. Tolkou; Michela Airoldi. 2016. "Novel and Conventional Technologies for Landfill Leachates Treatment: A Review." Sustainability 9, no. 1: 9.
Earth’s phosphorus resources are being depleted at an alarming rate, while at the same time eutrophication caused by its uncontrolled disposal in surface waters is considered as a significant environmental problem. In order to achieve phosphate recovery from the secondary effluents of an urban wastewater (biological) treatment plant, the adsorption onto single iron (GFH, Bayoxide and FeOOH) and onto binary iron-manganese (AquAsZero) oxy-hydroxides, as well as the ion exchange by using Purolite A200EMBCL resin, were investigated as post-treatment methods. Among them, laboratory batch experiments and dynamic Rapid Small Scale Column Tests (RSSCTs) evaluated AquAsZero, as the relatively better qualified material, presenting the higher efficiency. Based on these experimental results a pilot-plant, utilizing AquAsZero, was constructed and operated, treating 200 L/h. The breakthrough curves of RSSCTs for AquAsZero showed an adsorption capacity of 33.6 mg PO4 3−/gads at the equilibrium concentration of 3 mg PO4 3−/L, whereas at pilot-scale application the respective breakthrough curve indicated a similar adsorption capacity (31.5 mg PO4 3−/gads). The regeneration process, by applying a NaOH solution at pH range 12.6–13, resulted in the efficient (>80 wt.%) phosphate desorption, which in turn allows the multiple reuse of adsorbent media. Subsequently, phosphate was recovered from the alkaline regeneration (concentrate) solution by precipitation with the appropriate Ca2+ addition, as the respective calcium salt (hydroxy-apatite, HAP). Phosphate concentration in the finally collected amorphous (precipitated) solids from the laboratory scale experiments was around 51 wt.% and that of calcium was around 19 wt.%, while the corresponding concentrations in the precipitated solids collected from the pilot-scale experiments were around 36 wt.% for phosphate and 33 wt.% for calcium. This high phosphate content of finally recovered solids indicates their potential utilization as efficient (alternative) fertilizers.
Kyriaki Kalaitzidou; Manassis Mitrakas; Christina Raptopoulou; Athanasia Tolkou; Panagiota-Aikaterini Palasantza; Anastasios Zouboulis. Pilot-Scale Phosphate Recovery from Secondary Wastewater Effluents. Environmental Processes 2016, 3, 5 -22.
AMA StyleKyriaki Kalaitzidou, Manassis Mitrakas, Christina Raptopoulou, Athanasia Tolkou, Panagiota-Aikaterini Palasantza, Anastasios Zouboulis. Pilot-Scale Phosphate Recovery from Secondary Wastewater Effluents. Environmental Processes. 2016; 3 (S1):5-22.
Chicago/Turabian StyleKyriaki Kalaitzidou; Manassis Mitrakas; Christina Raptopoulou; Athanasia Tolkou; Panagiota-Aikaterini Palasantza; Anastasios Zouboulis. 2016. "Pilot-Scale Phosphate Recovery from Secondary Wastewater Effluents." Environmental Processes 3, no. S1: 5-22.
Athanasia Tolkou; Anastasios Zouboulis. Review of Recent Patents on Coagulation / Flocculation (C/F) Process: Methods and Applications with Emphasis on Phosphates Removal. Recent Patents on Materials Science 2014, 7, 151 -163.
AMA StyleAthanasia Tolkou, Anastasios Zouboulis. Review of Recent Patents on Coagulation / Flocculation (C/F) Process: Methods and Applications with Emphasis on Phosphates Removal. Recent Patents on Materials Science. 2014; 7 (2):151-163.
Chicago/Turabian StyleAthanasia Tolkou; Anastasios Zouboulis. 2014. "Review of Recent Patents on Coagulation / Flocculation (C/F) Process: Methods and Applications with Emphasis on Phosphates Removal." Recent Patents on Materials Science 7, no. 2: 151-163.
The aim of this work was to study the combination of an inorganic pre-polymerized coagulant (polyaluminum chloride [PACl]) with ferric species and polysilicic acid in various mixing orders Al/Fe/Si and OH/Al molar ratios, by applying two polymerization techniques for the production of a unique reagent, representing a more efficient coagulant than the respective commercially available (PACl-18) or laboratory-prepared (PACllab) for water or wastewater treatment. Several of coagulants’ derivatives were prepared and were examined by jar tests for the treatment of simulated surface water, contaminated by clay particles (turbidity) and humic acid (natural organic matter); pH, turbidity, UV254 nm absorbance, and residual Al were measured in the treated water. PSiFAC1.5:10:15 prepared by the co-polymerization technique was found to be the most efficient coagulant from all the tested compounds; in addition, no flocculant aid (polyelectrolyte) was required with this product. Low coagulant doses, about 1.5–2 mg/L were required for the reduction of turbidity values to lower than 1 NTU; furthermore, PSiFAC1.5:10:15 resulted in low residual aluminum concentration (about 140 μg Al/L). The most effective coagulants obtained were also used for the treatment of tannery wastewater to evaluate their performance and it was observed that high turbidity removal (~99%) was obtained at doses of about 100 mg/L. The most effective coagulants are under study for their potential use to alleviate membrane fouling in MBRs.
A.K. Tolkou; A.I. Zouboulis. Synthesis and coagulation performance of composite poly-aluminum-ferric-silicate-chloride coagulants in water and wastewater. DESALINATION AND WATER TREATMENT 2014, 53, 3309 -3318.
AMA StyleA.K. Tolkou, A.I. Zouboulis. Synthesis and coagulation performance of composite poly-aluminum-ferric-silicate-chloride coagulants in water and wastewater. DESALINATION AND WATER TREATMENT. 2014; 53 (12):3309-3318.
Chicago/Turabian StyleA.K. Tolkou; A.I. Zouboulis. 2014. "Synthesis and coagulation performance of composite poly-aluminum-ferric-silicate-chloride coagulants in water and wastewater." DESALINATION AND WATER TREATMENT 53, no. 12: 3309-3318.