scholarly journals Water Treatment in Hybrid Connection of Coagulation, Ozonation, UV Irradiation and Adsorption Processes

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1748
Author(s):  
Beata Karwowska ◽  
Elżbieta Sperczyńska ◽  
Lidia Dąbrowska
Keyword(s):  
Water Treatment ◽  
Metal Ions ◽  
Uv Irradiation ◽  
Uv Absorbance ◽  
Treatment Processes ◽  
Coagulation Process ◽  
Organic Pollutants Removal ◽  
Adsorption Processes ◽  
Pollutants Removal ◽  
Ozonation Process

In recent years, conventional water treatment systems have been supported by ozonation or UV irradiation processes. The efficiency of four hybrid processes: (1) coagulation and adsorption, (2) ozonation and coagulation, (3) ozonation, coagulation and adsorption, (4) ozonation, UV irradiation, coagulation and adsorption of inorganic and organic pollutants removal was analysed. In the presented study, the content of organic matter in natural water was evaluated as colour, oxidisability (OXI), total and dissolved organic carbon (TOC and DOC) content and UV absorbance at the wavelength of 254 nm for natural and modified water. Additionally, removal of Ni2+, Cd2+and Pb2+ ions during the treatment processes was analysed. The coagulation process with the use of polyaluminium chloride removed 45% of colour and 39, 26% and 45% of OXI, TOC and UV absorbance, respectively. Using the ozonation before coagulation increased efficiency of colour and UV254 absorbance reduction by 33% and 25%, respectively. Coagulation with both UV irradiation and adsorption had insignificant results on the analysed factors value. The coagulation process was the most efficient for metal ions removal (40–78%). The ozonation process before coagulation increased removal up to 55–85%. Additional irradiation with UV or using of the adsorbent during coagulation of initially ozonated water had an insignificant impact on metal ions concentration in water.

Adsorption and removal of triphenylmethane dyes from water by magnetic reduced graphene oxide

2014 ◽  
Vol 70 (10) ◽  
pp. 1663-1669 ◽  
Author(s):  
Jian-Zhong Sun ◽  
Zhi-Hong Liao ◽  
Rong-Wei Si ◽  
Gakai Peter Kingori ◽  
Fu-Xiang Chang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Reduced Graphene Oxide ◽  
Order Kinetic ◽  
Water Contaminants ◽  
Reduced Graphene ◽  
Organic Pollutants Removal ◽  
Adsorption Processes ◽  
Pollutants Removal ◽  
Magnetic Reduced Graphene Oxide

Triphenylmethane (TPM) dye is one of the most prevalent and recalcitrant water contaminants. Magnetic reduced graphene oxide (rGO) is an efficient adsorbent for organic pollutants removal. However, the performance and adsorption kinetics of magnetic rGO towards TPM have not yet been studied. In this study, a magnetic Fe3O4@rGO nano-composite, which could be easily removed from water with a simple magnetic separation step was synthesized and characterized. The magnetic rGO showed fast adsorption rate and high adsorption capacity towards different TPM dyes (the Langmuir monolayer adsorption capacity is 64.93 mg/g for adsorption of crystal violet). The adsorption processes are well-fitted to the pseudo-second-order kinetic model (R2 > 0.99) and the Langmuir isotherm model (R2 = 0.9996). Moreover, the magnetic rGO also showed excellent recycling and regeneration capabilities. The results indicated that adsorption with magnetic rGO would be a promising strategy to clean up the TPM contamination.

scholarly journals The Role of Macrophytes in Constructed Surface-flow Wetlands for Mine Water Treatment: A Review

2021 ◽  
Author(s):  
Joscha Opitz ◽  
Matthias Alte ◽  
Martin Bauer ◽  
Stefan Peiffer
Keyword(s):  
Water Treatment ◽  
Mine Water ◽  
Surface Flow ◽  
Environmental Benefits ◽  
Colloidal Iron ◽  
Aesthetic Appearance ◽  
Mine Water Treatment ◽  
Organic Pollutants Removal ◽  
Pollutants Removal ◽  
Settling Ponds

AbstractConstructed wetlands are a standard sustainable technology in waste and mine water treatment. Whereas macrophytes actively contribute to decomposition and/or removal of wastewater’s organic pollutants, removal of hydrolysable metals from mine water is not attributable to direct metabolic, but rather various indirect macrophyte-related mechanisms. These mechanisms result in higher treatment efficiency of (vegetated) wetlands relative to (unvegetated) settling ponds. Contribution of macrophytes to treatment predominantly includes: enhanced biogeochemical oxidation and precipitation of hydrolysable metals due to catalytic reactions and bacterial activity, particularly on immersed macrophyte surfaces; physical filtration of suspended hydrous ferric oxides by dense wetland vegetation down to colloids that are unlikely to gravitationally settle efficiently; scavenging and heteroaggregation of dissolved and colloidal iron, respectively, by plant-derived natural organic matter; and improved hydrodynamics and hydraulic efficiency, considerably augmenting retention and exposure time. The review shows that constructed surface-flow wetlands have considerable advantages that are often underestimated. In addition to treatment enhancement, there are socio-environmental benefits such as aesthetic appearance, biotope/habitat value, and landscape diversity that need to be considered. However, there is currently no quantitative, transferrable approach to adequately describe the effect and magnitude of macrophyte-related benefits on mine water amelioration, let alone clearly assign optimal operational deployment of either settling ponds or wetlands. A better (quantitative) understanding of underlying processes and kinetics is needed to optimise assembly and sizing of settling ponds and wetlands in composite passive mine water treatment systems.

scholarly journals Optimizing NOM Removal: Impact of Calcium Chloride

2021 ◽  
Vol 13 (11) ◽  
pp. 6338
Author(s):  
Alfredo Gonzalez-Perez ◽  
Kristofer Hägg ◽  
Fabrice Duteil
Keyword(s):  
Water Treatment ◽  
Calcium Chloride ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Adverse Health Effects ◽  
Surface Water Treatment ◽  
Treatment Processes ◽  
Aluminum Sulphate ◽  
Adsorption Processes ◽  
Sedimentation Processes

Understanding the character of natural organic matter (NOM) and assessing its impact on water quality is paramount for managers of catchments and water utilities. For drinking-water producers, NOM affects disinfectant demand and the formation of by-products which can have adverse health effects. NOM content in raw waters also has an impact on water treatment processes by increasing required coagulant dosages, reducing the effectiveness of adsorption processes and fouling membrane systems. This study investigated the effects of calcium chloride (CaCl2) as a co-coagulant in Al3+ and Fe3+ assisted coagulation, flocculation and sedimentation processes for NOM-removal from raw water collected from Lake Bolmen, in southern Sweden. Jar tests were conducted at Ringsjö Water Works (WW), a surface water treatment plant (WTP), to investigate the potential reduction in primary coagulants aluminum sulphate (Al2(SO4)3) and ferric chloride (FeCl3). This work shows that CaCl2 can, in certain situations, reduce the need for primary coagulants, which would reduce the environmental impact and costs associated with primary coagulant consumption.

scholarly journals Cyanobacterial biomass: a striking factor to decrease polyaluminium chloride (PACl) coagulation efficiency during a successive bloom

2021 ◽  
Author(s):  
Weijun Song ◽  
Jie Zeng ◽  
Xi Li ◽  
Yu Xie ◽  
Xunfang Wu
Keyword(s):  
Water Treatment ◽  
Cell Density ◽  
Ph Value ◽  
Cyanobacterial Blooms ◽  
Water Treatment Process ◽  
Treatment Processes ◽  
Coagulation Process ◽  
Cyanobacterial Biomass ◽  
Source Waters

Abstract Occurrence of cyanobacterial blooms in source waters challenges water treatment processes. During a successive bloom, typical characteristics of elevated cell-density and pH was observed from development to maintenance stage. However, studies about their influences on coagulation process were limited. Here, PACl coagulation experiments were conducted to investigate Microcystis removal with varied pH and cell-density. Results showed that PACl coagulation alone was sufficient to remove Microcystis with low cell-density (105–106 cells mL−1), since elevated pH value (8.5–9.5) can promote PACl coagulation possibly ascribed to sweeping cells via neutral gelatinous precipitate of alum. Nevertheless, elevated cyanobacterial biomass was a striking factor to decrease Microcystis removal (80–100%) by PACl coagulation, since its inhibitory effects on coagulation process could not be offset by in situ elevated pH value. Chlorination-assisted (1 mg L−1) coagulation was recommended to treat cyanobacteria-laden source waters with high cell-density of >107 cells mL−1, as it promoted cyanobacterial removal and achieved the highest removal ratio of DOC and turbidity among these treatments. These findings would provide an important reference for water supplies to choose proper water treatment process to treat cyanobacteria-laden source waters during a successive bloom.

scholarly journals Parallel study on removal efficiency of pharmaceuticals and PFASs in advanced water treatment processes: Ozonation, GAC adsorption, and RO processes

2020 ◽  
Vol 27 (1) ◽  
pp. 200509-0
Author(s):  
Hyun-Seok Choe ◽  
Ki Yong Kim ◽  
Jeong-Eun Oh ◽  
Jae-Hyuk Kim
Keyword(s):  
Water Treatment ◽  
Operating Conditions ◽  
Membrane Processes ◽  
Chemical Structures ◽  
Treatment Processes ◽  
Stable Chemical ◽  
Adsorption Processes ◽  
Ro Membrane ◽  
Physical Treatments ◽  
Gac Adsorption

We aimed to assess the removal efficiencies of four pharmaceuticals (carbamazepine, crotamiton, metformin, and sulfamethoxazole) and four poly- and perfluoroalkyl substances (PFASs) (PFHxA, PFHxS, PFOA, and PFOS) by lab-scale ozonation, granular activated carbon (GAC) adsorption, and reverse osmosis (RO) membrane processes under varying operating conditions. Ozonation and GAC adsorption processes were conducted at two temperatures (5 and 25°C) and three pH conditions (3, 7, and 11). The membrane process was performed using an unstirred cell with two different RO membranes. The most pharmaceuticals were effectively removed by ozonation, whereas metformin and PFASs were unaffected due to their stable chemical structures. In the GAC process, metformin was hardly removed under acidic conditions but it was enhanced by over 90%. PFASs were effectively removed by GAC adsorption and RO membrane processes. The RO membrane for brackish water treatment showed higher rejection than that for residential water treatment. Moreover, the rejection of PFAS increased as the molecular weight increased. A strategy was found to effectively remove the remaining metformin in most advanced water treatment processes. Chemically persistent PFASs were hardly removed by the ozonation process but were effectively removed by physical treatments such as GAC adsorption and RO membrane processes.

scholarly journals Water Ozonation with Copper Catalyst for Organic Pollutants Removal

2012 ◽  
Vol 14 (3) ◽  
pp. 219
Author(s):  
A.V. Shabalina ◽  
G.M. Mokrousov ◽  
E.D. Fakhrutdinova ◽  
T.I. Izaak ◽  
J.J. Wu
Keyword(s):  
Surface Layer ◽  
Organic Pollutants ◽  
High Efficiency ◽  
Catalyst Surface ◽  
Copper Catalyst ◽  
Copper Surface ◽  
Organic Pollutants Removal ◽  
Pollutants Removal ◽  
Low Efficiency ◽  
Ozonation Process

This work presents high-porous honeycomb copper catalyst for organic pollutants removal from water during the ozonation process. This catalyst demonstrates high efficiency in removing target compounds (oxalic and benzoic acids and methylene blue), appropriate stability and resistance to abrasion. Copper catalyst behavior in the ozonation process was investigated. It was found that under ozonation conditions reversible  oxidation/reduction of the copper surface layer takes place. In contact with ozone, copper surface can easily be oxidized resulting in formation of copper oxides. As expected, it leads to decomposition of organic substances during ozonation and reduction of copper catalyst surface layer. Copper (II) oxide was also found to be an active catalyst in oxidation of organic pollutants with ozone, but it is not appropriate to use bulk CuO because of its low abrasion resistance. Copper (II) ions that form due to dissolution of catalyst surface layer with participation of the acidic medium in the ozonation process were detected. Pollutants removal efficiency at different pH values was also studied. It was found that catalytic removal of organic pollutants takes place at low pH, as compared to low efficiency of hydroxyl-radical formation at the acidic pH. A possible scheme for organic pollutants removal during ozonation with copper catalyst was proposed.

Water Treatment Considerations–Aquatic Humus

1983 ◽  
Vol 15 (S2) ◽  
pp. 95-101 ◽  
Author(s):  
E T Gjessing
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Humic Substances ◽  
Health Effects ◽  
Surface Waters ◽  
Cold Climate ◽  
Treatment Processes ◽  
Aquatic Humus ◽  
Treatment Considerations

For several reasons the surface waters in cold climate areas are coloured due to humic substances. There are two major objections against humus in drinking water, the first is concerned with aesthetical and practical problems and the second is due to indirect negative health effects. There are essentially three different methods in use today for the removal or reduction of humus colour in water: (1) Addition of chemicals with the intention of reducing the “solubility”, (2) Addition of chemicals in order to bleach or mineralize the humus, and (3) Filtration with the intention of removal of coloured particles and some of the “soluble” colour. The treatment processes are discussed.

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