Improving the efficiency of rapid sandfilters by adding small amounts of ferric salts (βFe ≤ 0.1 mg·L-1)

2002 ◽  
Vol 2 (1) ◽  
pp. 191-204
Author(s):  
R. Schick ◽  
R. Winzenbacher ◽  
H.-H. Stabel ◽  
M. Jekel
Keyword(s):  
Alkaline Earth ◽  
Large Scale ◽  
Iron Hydroxides ◽  
Iron Salts ◽  
Co Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Alkaline Earth Cations ◽  
Rapid Sand Filtration

Improved removal of suspended matter during the treatment of water from Lake Constance has been achieved by pre-ozonation (βO3 = 1 mg·L-1 corresponding to 0.8 mg O3/mg DOC) and the addition of small quantities of iron salts (βFe≤0.1 mg·L-1; “Fe(III)-assisted filtration”) followed by rapid sand filtration. As shown by investigations on a large-scale installation (bypass mode) over several years, this procedure reliably reduces particulate matter in the water by about 3 orders of magnitude in long-term use. However, the high efficacy of Fe(III)-assisted filtration cannot be explained on the basis of known coagulation mechanisms (adsorption-charge neutralization, co-precipitation). Instead, the essential step was found to be the conditioning of the filter medium by coating it with colloids containing Fe(OH)3, and this “Fe coating” process only occurs in the presence of alkaline earth cations (especially Ca2+). According to further experiments, the enhanced solid-liquid separation was ultimately traced to chemical interactions such as the formation of calcium-NOM bridges between the iron hydroxides and other solids.

Investigations on the filtration of natural aquatic suspensions supported by dosing small amounts of Fe(III)-salts (βFe ≤ 0.1 mg.L-1): mode of action and basic design criteria

2002 ◽  
Vol 2 (2) ◽  
pp. 91-98
Author(s):  
R. Winzenbacher ◽  
R. Schick ◽  
H.-H. Stabel ◽  
M. Jekel
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Iron Hydroxides ◽  
Essential Step ◽  
Iron Salts ◽  
Alkaline Earths ◽  
Co Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation

Improved removal of particles during the treatment of natural aquatic suspensions has been achieved by pre-ozonation and the addition of small quantities of iron salts (βFe ≤ 0.1 mg.L-1; “Fe(III)-assisted filtration”) followed by rapid filtration. As shown by investigations on a large-scale installation at Lake Constance Water Supply, this procedure reliably reduces suspended solids by at least 2-3 powers of ten in long-term use. However, the high efficacy of Fe(III)-assisted filtration cannot be explained on the basis of known coagulation mechanisms (like adsorption-charge neutralization, co-precipitation). Instead, the essential step was found to be the conditioning of the filter medium by coating it with colloids containing Fe(OH)3, and this “Fe coating” process occurs only in the presence of alkaline earths (especially Ca2+). According to further experiments, the enhanced solid-liquid separation was ultimately traced to chemical interactions such as the formation of calcium-organic association structures between the iron hydroxides and other solids. For design of Fe(III)-assisted filtration steps, finally, a βCa/DOC ratio above 40 mg.mg-1 and pre-oxidation with ozone dosages not exceeding 2 mg O3/mg DOC was recommended.

scholarly journals The key role of contact time in elucidating the mechanisms of enhanced decontamination by Fe0/MnO2/sand systems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Viet Cao ◽  
Ghinwa Alyoussef ◽  
Nadège Gatcha-Bandjun ◽  
Willis Gwenzi ◽  
Chicgoua Noubactep
Keyword(s):  
Contact Time ◽  
Diffusive Transport ◽  
Iron Hydroxides ◽  
Iron Corrosion ◽  
Short Term ◽  
Batch Studies ◽  
Water Decontamination ◽  
Co Precipitation

AbstractMetallic iron (Fe0) has shown outstanding performances for water decontamination and its efficiency has been improved by the presence of sand (Fe0/sand) and manganese oxide (Fe0/MnOx). In this study, a ternary Fe0/MnOx/sand system is characterized for its discoloration efficiency of methylene blue (MB) in quiescent batch studies for 7, 18, 25 and 47 days. The objective was to understand the fundamental mechanisms of water treatment in Fe0/H2O systems using MB as an operational tracer of reactivity. The premise was that, in the short term, both MnO2 and sand delay MB discoloration by avoiding the availability of free iron corrosion products (FeCPs). Results clearly demonstrate no monotonous increase in MB discoloration with increasing contact time. As a rule, the extent of MB discoloration is influenced by the diffusive transport of MB from the solution to the aggregates at the bottom of the vessels (test-tubes). The presence of MnOx and sand enabled the long-term generation of iron hydroxides for MB discoloration by adsorption and co-precipitation. Results clearly reveal the complexity of the Fe0/MnOx/sand system, while establishing that both MnOx and sand improve the efficiency of Fe0/H2O systems in the long-term. This study establishes the mechanisms of the promotion of water decontamination by amending Fe0-based systems with reactive MnOx.

Magnetized manganese oxide nanocomposite for effective decontamination of Cd(II) from wastewaters

2016 ◽  
Vol 74 (12) ◽  
pp. 2762-2772 ◽  
Author(s):  
Ana Pacheli Heitmann ◽  
Gabriela C. Silva ◽  
Paulo Renato P. Paiva ◽  
Maria Sylvia S. Dantas ◽  
Virginia S. T. Ciminelli ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Large Scale ◽  
Transmission Electron Microscopy Image ◽  
Hysteresis Curve ◽  
A Value ◽  
Transmission Electron ◽  
Microscopy Image ◽  
Pseudo Second Order ◽  
Solid Liquid ◽  
Solid Liquid Separation

In this study, a composite with magnetic properties has been successfully synthesized by a novel and environmentally friendly route and is applied to Cd(II) adsorption for water decontamination. The quantification of the phases obtained by Rietveld refinement has shown the presence of 84% of Mn3O4 and 16% of Fe3O4. Transmission electron microscopy image shows an aggregate of Mn3O4 nanoparticles without specific orientation and the predominance of octahedral morphology with nanoparticles size estimated around 25–30 nm. The Cd(II) adsorption isotherm is fitted using the Langmuir–Freundlich model. The estimated maximum adsorption capacities of Cd(II) at pH 6 and 7 are similar (0.28 ± 0.02 and 0.31 ± 0.02 mg/m2, respectively). The kinetic results show that the studied system follows the pseudo-second-order model. The Raman results indicate that Cd is being specifically adsorbed by the Mn3O4 in the composite. The hysteresis curve of the composite Mn3O4/Fe3O4 has changed when compared to the pure magnetite; however, the coercive field after the addition of manganese oxide remains unaltered and does not change with a value around 158 Oe. The turbidity tests showed that the magnetic sedimentation was efficient and promising for wastewater treatment in large scale. These materials can be conveniently recovered by magnetic separation, avoiding the filtration steps, which will make easier the solid–liquid separation operation that follows the adsorption process.

Performance Quantification of Manure Management Systems at 11 Northeastern U.S. Dairy Farms

2018 ◽  
Vol 34 (6) ◽  
pp. 973-1000 ◽  
Author(s):  
Jason P Oliver ◽  
Jenna E Schueler ◽  
Curt A Gooch ◽  
Stephanie Lansing ◽  
Diana S Aga
Keyword(s):  
Biogas Production ◽  
Dairy Farm ◽  
Management Systems ◽  
Manure Management ◽  
Long Term Storage ◽  
Manure Slurry ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Term Storage

Abstract. The performance of manure management systems, on a component-by-component basis, at 11 Northeastern U.S. dairy farm concentrated animal feeding operations (CAFO) was quantified by semi-continuous monitoring for 15 months. Each collaborating farm (CF) had one or more of the following: solid-liquid separation (SLS), separated solids(SS) treatment by lime, rotary drum processing and windrow composting, anaerobic treatment by anaerobic digestion (AD), lagoons, and long-term storage(s). Operational and performance metrics included: temperature, pH, total solids (TS), volatile solids (VS), loading rates, and biogas production. Generally, most CFs had functional and well-operating systems based on expected and optimal operating conditions and sample constituent changes, although, sampling and monitoring limitations restricted complete performance assessments. Despite the limitations, differences in treatment effectiveness were noted, which were often related to influent conditions. Higher SLS solids capture efficiencies (typ. > 40%), and biogas production rates (= 3.8 m3 d-1 lactating cow equivalents (LCE)-1), were associated with more concentrated manure slurry influents [TS > 0.050 g g-1 wet basis (w.b.)]. Anaerobic digester configuration and the use of co-substrates also influenced anaerobic treatments. Generally, intensively managed ADs outperformed passively managed lagoons, and co-digestion enhanced biogas production (= 4.3 m3 d-1 LCE-1) and VS reductions (up to 48% w.b.), though co-digestion sometimes hampered process stability. The effectiveness of SS processing was also treatment dependent, with well-managed windrows yielding the greatest increases in TS concentrations (up to 0.600 g g-1 w.b.). Long-term storage of manure slurry had modest, non-significant, impacts on TS and VS concentrations, and pH. This work illustrated a range of manure management systems used on NE dairy farm CAFOs, parameterized their treatment of manure slurries and SS, and established a baseline for additional studies aimed at the capacity of these systems to mitigate emerging contaminant like antibiotic residues. Keywords: Anaerobic digestion, Antimicrobial resistance, Biogas, Compost, Lime treatment, Long-term storage, Solid-liquid separation.

scholarly journals Sustainable Development of a Peripheral Mountain Region on the State Border: Case Study of Moravské Kopanice Microregion (Moravia)

2019 ◽  
Vol 11 (19) ◽  
pp. 5540 ◽  
Author(s):  
Antonín Vaishar ◽  
Milada Šťastná
Keyword(s):  
Sustainable Development ◽  
Environmental Sustainability ◽  
Rural Areas ◽  
Large Scale ◽  
The Social ◽  
Gaseous Waste ◽  
The Moment ◽  
Solid Liquid

The sustainability of rural areas is considered to be most threatened in peripheral, hardly accessible microregions with insufficient economical sources. The paper analyses one such rural area in the eastern part of Moravia from the viewpoint of individual economic, social, and environmental sustainability pillars. The area under study is the mountain territory on the border with Slovakia, which is under large-scale landscape protection. The area with very limited economic sources has been impacted with a change to the geopolitical situation after 1993 (from the centre of Czechoslovakia to the fringe of Czechia). It was stated that the environmental pillar is in the best of conditions; however, perhaps threatened with missing technical infrastructure in relation to the disposal of solid, liquid, and gaseous waste, the social pillar is improving in relation to the post-productive transition, whereas the economic pillar is the most fragile because of its dependence on exogenous jobs in surrounding towns. In general, the microregion seems to be sustainable at the moment. Long-term sustainability will depend on the general economic, demographic, and climatic development of the country and Europe.

scholarly journals Adsorption of nitrate and nitrite from aqueous solution by magnetic Mg/Fe hydrotalcite

2021 ◽  
Author(s):  
Jing Chen ◽  
Yawei Wei ◽  
Haoyu Ji ◽  
Pengliang Guo ◽  
Dongjin Wan ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Langmuir Model ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Magnetic Strength ◽  
Calcination Method ◽  
Co Precipitation ◽  
Nitrate And Nitrite ◽  
Solid Liquid ◽  
Solid Liquid Separation

Abstract In this study, magnetic Mg/Fe hydrotalcite calcined material (M-CHT) was synthesized through co-precipitation and calcination method, and was used to effectively remove nitrate and nitrite from water. M-CHT can restore its original layered structure after the adsorption of nitrate or nitrite, and can be easily separated by the applied magnetic field. The first-order and pseudo-second-order kinetic models (R2 ≥ 0.97) can better describe the adsorption kinetic process. The equilibrium isotherm showed that the Langmuir model provided a better fit to the experimental data than the Freundlich model for nitrates and nitrites. With temperature increased from 298 to 308 K, the maximum adsorption capacity obtained by the Langmuir model increased from 10.60 to 16.90 mg-N/g for nitrate and 7.89 to 14.28 mg-N/g for nitrite, respectively. The adverse effect of coexisting anions ranked in the order of ClO4− > Cl− > SO42− > F− > CO32− > PO43−. The actual Fe2+/Fe3+ value of M-CHT (0.56) is nearly consistent with the theoretical value of 0.5, and the saturation magnetic strength value of M-CHT is 9.15 emu/g, greatly contributing to the solid-liquid separation. Overall, M-CHT with features of magnetic properties and satisfactory adsorption capacity exhibits the greatly promising for application in wastewater purification.

scholarly journals Green Process: Improved Semi-Continuous Fermentation of Pichia pastoris Based on the Principle of Vitality Cell Separation

2021 ◽  
Vol 9 ◽  
Author(s):  
Denggang Wang ◽  
Wenjie Li ◽  
Xinying Zhang ◽  
Shuli Liang ◽  
Ying Lin
Keyword(s):  
Pichia Pastoris ◽  
Metal Ions ◽  
Large Scale ◽  
Continuous Fermentation ◽  
Fermentation Broth ◽  
Pectate Lyase ◽  
Salt Bridges ◽  
The Cost ◽  
Solid Liquid ◽  
Solid Liquid Separation

The large-scale fermentation of Pichia pastoris for recombinant protein production would be time consuming and produce a large amount of waste yeast. Here we introduce a novel semi-continuous fermentation process for P. pastoris GS115 that can separate vitality cells from broth and recycle the cells to produce high-secretory recombinant pectate lyase. It is based on differences in cell sedimentation coefficients with the formation of salt bridges between metal ions and various cell states. Compared to batch-fed cultivation and general semi-continuous culture, the novel process has significant advantages, such as consuming fewer resources, taking less time, and producing less waste yeast. Sedimentation with the addition of Fe3+ metal ions consumed 14.8 ± 0.0% glycerol, 97.8 ± 1.3% methanol, 55.0 ± 0.9 inorganic salts, 81.5 ± 0.0% time cost, and 77.0 ± 0.1% waste yeast versus batch-fed cultivation to produce an equal amount of protein; in addition, the cost of solid–liquid separation was lower for cells in the collected fermentation broth. The process is economically and environmentally efficient for producing recombinant proteins.

scholarly journals The Key Role of Contact Time in Elucidating the Mechanism of Enhanced Decontamination by Fe0/mno2/sand Systems

2021 ◽  
Author(s):  
Viet Cao ◽  
Ghenwa Alyoussef ◽  
Nadège Gatcha-Bandjun ◽  
Willis Gwenzi ◽  
Chicgoua Noubactep
Keyword(s):  
Contact Time ◽  
Diffusive Transport ◽  
Iron Hydroxides ◽  
Iron Corrosion ◽  
Short Term ◽  
Batch Studies ◽  
Water Decontamination ◽  
Co Precipitation

Abstract Metallic iron (Fe0) has shown outstanding performances for water decontamination and its efficiency has been improved by the presence of sand (Fe0/sand) and manganese oxide (Fe0/MnOx). In this study, a ternary Fe0/MnOx/sand system is characterized for its discoloration efficiency of methylene blue (MB) in quiescent batch studies for 7, 18, 25 and 47 d. The objective was to understand the fundamental mechanisms of water treatment in Fe0/H2O systems using MB as an operational tracer of reactivity. The premise was that, in the short term, both MnO2 and sand delay MB discoloration by avoiding the availability of free iron corrosion products (FeCPs). Results clearly demonstrate no monotonous increase in MB discoloration with increasing contact time. As a rule, the extent of MB discoloration is influenced by the diffusive transport of MB from the solution to the aggregates at the bottom of the vessels (test-tubes). The presence of MnOx and sand enabled the long-term generation of iron hydroxides for MB discoloration by adsorption and co-precipitation. Results clearly reveal the complexity of the Fe0/MnOx/sand system, while establishing that both MnOx and sand improve the efficiency of Fe0/H2O systems in the long-term. This study establishes the mechanisms of the promotion of water decontamination by amending Fe0-based systems with reactive MnOx.

scholarly journals Improvements to the Water Quality of the Acidic Berkeley Pit Lake due to Copper Recovery and Sludge Disposal

2019 ◽  
Vol 39 (3) ◽  
pp. 427-439
Author(s):  
Christopher H. Gammons ◽  
Gary A. Icopini
Keyword(s):  
Water Quality ◽  
Water Column ◽  
Large Scale ◽  
Copper Recovery ◽  
Pit Lake ◽  
Lime Treatment ◽  
Sludge Disposal ◽  
Berkeley Pit ◽  
Co Precipitation

AbstractThe chemistry and limnology of the Berkeley Pit lake, located in Butte, Montana, have substantially changed during the past 15 years. These changes are due to: (1) a large-scale Cu recovery project in which deep water was pumped to a Cu precipitation plant and returned to the surface of the lake; and (2) in-pit disposal of lime-treatment sludge. As a consequence, the lake has shifted from a meromictic to a holomictic state, over 99% of the dissolved Fe has precipitated as schwertmannite and other ferric solids, the total acidity of the water column has dropped by roughly 35%, and the pH has risen from about 2.5 to near 4.1. Whereas most of the lake was anoxic prior to 2013, the water column now contains > 6 mg/L dissolved oxygen from the lake surface to the deepest levels sampled (> 150 m). Concentrations of several other solutes, including As, P, Cr, and V, have fallen sharply due to adsorption or co-precipitation with Fe, while other species, such as Al, Mg, and Mn, have increased due to dissolution of solids in the sludge. Although the Cu recovery circuit was discontinued in 2013, in-pit disposal of sludge is expected to continue. The pit water is now close to saturation with basaluminite, and the pH should remain poised in the range of 4.1–4.5 for many years as Al precipitates out of the water column. Pumping and treating of pit water is set to commence in 2019, and will continue for the foreseeable future. Continued in-pit disposal of sludge should translate into long term water-quality improvement and a decrease in annual lime-consumption costs. Although the Berkeley Pit still has a long ways to go before it will meet water quality standards, it is heartening to mine-water specialists that the pit lake may not be a problem that is “too big to fix”.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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