scholarly journals Ti and TiAl melting with a semi-industrial PAMCHR

2020 ◽  
Vol 321 ◽  
pp. 10010
Author(s):  
Fabienne Ruby-Meyer ◽  
Emiliane Doridot ◽  
Jérôme Delfosse ◽  
Stéphane Hans
Keyword(s):  
Pilot Scale ◽  
Solidification Structure ◽  
Industrial Scale ◽  
Operating Pressure ◽  
Plasma Arc ◽  
Chemical Mechanisms ◽  
Pilot Trials ◽  
Physico Chemical ◽  
Ingot Quality ◽  
Work Done

Upscaling from laboratory trials to industrialization is a critical step in the development of new metallurgical processes and products. Pilot trials are an important way to provide data that can be used to better understand and model the industrial-scale process. MetaFensch has invested in a semi-industrial Plasma Arc Melter Cold Hearth Refiner (PAMCHR) in order to support the development of the recycling of titanium scraps into aeronautical grade titanium alloy ingots. This pilot supports the industrial scale PAMCHR of the company Ecotitanium in the frame of a collaborative project with Aubert & Duval and Safran as industrial partners. The work done on the pilot scale PAMCHR consists in studying the influence of various parameters like the type of melting feedstock, plasma arc parameters, operating pressure on the final quality of the cast ingot. The goal is to understand the physico-chemical mechanisms involved in the plasma arc interacting with the liquid metal in order to optimize the melting and refining parameters for the industrial scale furnace Ecotitanium (Ti64 alloy). Ti64 and TiAl ingots were cast in 150 mm and 100 mm diameter. Chemical composition and solidification structure were characterized. The effect of the different process parameters on the titanium melt and on the ingot quality are studied. Examples of exploitation of the thermograms obtained with the thermal camera situated above the refining cold hearth will also be presented in this paper.

Depressed filtration ripening enhances removal of Cryptosporidium parvum

2002 ◽  
Vol 2 (3) ◽  
pp. 159-168 ◽  
Author(s):  
V. Gitis ◽  
R.C. Haught ◽  
R.M. Clark ◽  
E. Radha Krishnan
Keyword(s):  
Surface Water ◽  
Cryptosporidium Parvum ◽  
Pilot Scale ◽  
Kaolin Clay ◽  
Clay Particles ◽  
Physico Chemical ◽  
Cryptosporidium Parvum Oocysts ◽  
Granular Filtration ◽  
Electrostatic Adhesion ◽  
Innovative Concept

Pilot-scale experiments were conducted to investigate removal of Cryptosporidium parvum by contact granular filtration. The research demonstrated enhanced removal of Cryptosporidium parvum in the presence of kaolin particles. This is believed to be due electrostatic adhesion of Cryptosporidium parvum oocysts to the kaolin clay particles. The elementary physico-chemical interactions between filter granules and suspension particles will be discussed. This innovative concept was successfully implemented to reduce the ripening sequence of subsequent filtration experimental test runs by the addition of large surface area particles to slurry of kaolin and Cryptosporidium parvum in surface water.

Viability of nematode eggs in high rate algal ponds: the effect of physico-chemical conditions

2000 ◽  
Vol 42 (10-11) ◽  
pp. 371-374 ◽  
Author(s):  
S. Araki ◽  
J. M. González ◽  
E. de Luis ◽  
E. Bécares
Keyword(s):  
Hydraulic Retention Time ◽  
Pilot Scale ◽  
High Rate ◽  
Sterile Water ◽  
Egg Viability ◽  
High Rate Algal Ponds ◽  
Helminth Eggs ◽  
Physico Chemical ◽  
Nematode Eggs ◽  
Chemical Conditions

The viability of Parascaris equorum eggs was studied in two experimental pilot-scale high-rate algal ponds (HRAPs) working in parallel with 4 and 10 days hydraulic retention time respectively. Semi-permeable bags of cellulose (15000 daltons pore size) were used to study the effect of physico-chemical conditions on the survival of these helminth eggs. Three thousand eggs were used in each bag. Replicates of these bags were submerged for 4 and 10 days in the HRAPs and egg viability was compared with that in control bags submerged in sterile water. After 4 days exposure, 60% reduction in viability was achieved, reaching 90% after 10 days, much higher than the 16% and 25% found in the control bags for 4 and 10 days respectively. Ionic conditions of the HRAP may have been responsible for up to 50–60% of the egg mortality, suggesting that mortality due to the ionic environment could be more important than physical retention and other potential removal factors.

Costs of tertiary treatment of municipal wastewater by rapid sand filter with coagulants and UV

2003 ◽  
Vol 3 (4) ◽  
pp. 145-152 ◽  
Author(s):  
H. Heinonen-Tanski ◽  
P. Juntunen ◽  
R. Rajala ◽  
E. Haume ◽  
A. Niemelä
Keyword(s):  
Total Phosphorus ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Treated Wastewater ◽  
Tertiary Treatment ◽  
Sand Filter ◽  
Physico Chemical ◽  
Bathing Waters ◽  
Filtration Unit ◽  
Microbial Groups

Municipal treated wastewater has been tertiary treated in a pilot-scale rapid sand filter. The filtration process was improved by using polyaluminium coagulants. The sand-filtered water was further treated with one or two UV reactors. The quality changes of wastewater were measured with transmittance, total phosphorus, soluble phosphorus, and somatic coliphages, FRNA-coliphages, FC, enterococci and fecal clostridia. Sand filtration alone without coagulants improved slightly some physico-chemical parameters and it had almost no effect on content of microorganisms. If coagulants were used, the filtration was more effective. The reductions were 88-98% for microbial groups and 80% for total phosphorus. The wastewater would meet the requirements for bathing waters (2,000 FC/100 ml, EU, 1976). UV further improved the hygiene level; this type of treated wastewater could be used for unrestricted irrigation (2.2 TC/100 ml, US.EPA 1992). The improvement was better if coagulants were used. The price for tertiary treatment (filtration + UV) would have been 0.036 Euro/m3 according to prices in 2001 in 22 Mm3/a. The investment cost needed for the filtration unit was 0.020 Euro/m3 (6%/15a). Filtration with coagulants is recommended in spite of its costs, since the low transmittance of unfiltered wastewater impairs the efficiency of the UV treatment.

scholarly journals Groundwater physico-chemical properties and water quality changes in shallow aquifers in arid saline wetlands, Ouargla, Algeria

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Fethi Medjani ◽  
Mohamed Djidel ◽  
Sofiane Labar ◽  
Louiza Bouchagoura ◽  
Chouaib Rezzag Bara
Keyword(s):  
Water Quality ◽  
Chemical Properties ◽  
High Water ◽  
Quality Changes ◽  
Shallow Aquifers ◽  
Shallow Water Table ◽  
Chemical Mechanisms ◽  
Desert Region ◽  
Physico Chemical ◽  
Hypersaline Water

AbstractShallow aquifers are vulnerable to natural geogenic processes as well as anthropogenic influences, and this is especially apparent in desert regions. Within arid and hyperarid climates, evaporation is a controlling hydrologic process leads to an important increase in the concentration of dissolved minerals of both surface water and groundwater. In groundwater, this increase is not only dependent on shallow water table depth, but also on the hydraulic properties of sediments present within the unsaturated zone of the aquifer itself. The main objective of this research is to investigate possible mechanisms that might influence water quality changes under seasonal conditions in shallow aquifers situated within the Saharan desert region of Algeria. In this work, we focus on observed changes in hydrogeochemical characteristics, and the possible responsible processes. Under arid conditions, high water mineralization results in hypersaline water or brine solution formation within shallow aquifers. Due to active physico-chemical mechanisms such as Na+/Ca2+ ion exchange, the successive precipitation of calcite, gypsum, mirabilite or blœdite and halite is induced. Biological processes were also observed as prevalent; evidenced by large measured variations in CO2 load concentrations. These processes contributed to an inverse relationship between CO2 and O2 concentrations within the shallow aquifers studied.

scholarly journals Development of a Laboratory-Scale Thermal-Arc-Plasma Reactor and its Application in the Pyrolysis of Petroleum Oily Sludge

2020 ◽  
Vol 2 (1) ◽  
pp. 15-27
Author(s):  
Abubakar M. Ali ◽  
Mohd A. Abu-Hassan ◽  
Raja R.K. Ibrahim ◽  
Bala I. Abdulkarim
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Waste Treatment ◽  
Treatment Time ◽  
Plasma Reactor ◽  
Pilot Scale ◽  
Oily Sludge ◽  
Arc Plasma ◽  
Plasma Arc ◽  
Mass Reduction

Waste treatment using thermal arc plasma is well established and laboratory/pilot scale plasma reactors were developed and their performances for the destruction of different hazardous wastes, other than petroleum oily sludge, were studied. This work aims to extend the plasma technology to the pyrolysis of hazardous petroleum oily sludge. A 4.7 kW thermal arc plasma reactor was developed using a standard TIG arc welding torch. The transferred arc plasma reactor was used to treat 20 g/batch of petroleum oily sludge. The prevailing temperature inside the reactor ranges between 356 – 1694 oC. The plasma arc temperature increased with increasing plasma arc current and also with increasing plasma gas flow-rate. A vitreous slag and a flue gas were generated as products. A mass reduction of between 36.87 – 91.40% and a TOC reduction of 21.47 – 93.76% were achieved in the treatment time of 2 – 5 min. The mass reduction was observed to increase with treatment time. However, the increase was more rapid between the 3rd and the 4th min of the treatment. The flue gas produced contains H2 (43.79 – 50.97 mol%), H2O (26.60 – 30.22 mol%), CO (8.45 – 11.18 mol%), CO2 (5.12 – 10.35 mol%), CH4 (2.17 – 3.38 mol%), C2H2 (0.86 – 2.69 mol%) and C2H4 (0.76 – 2.17 mol%). Thus, the thermal plasma reactor provides a suitable method of treating petroleum oily sludge.

Chemical phosphorus removal model based on equilibrium chemistry

2005 ◽  
Vol 52 (10-11) ◽  
pp. 549-555 ◽  
Author(s):  
I. Takács ◽  
S. Murthy ◽  
P.M. Fairlamb
Keyword(s):  
Phosphorus Removal ◽  
Dissociation Constants ◽  
Chemical Precipitation ◽  
Weak Acid ◽  
Chemical Mechanisms ◽  
Model Based ◽  
Precipitation Model ◽  
Physico Chemical ◽  
Ph Range ◽  
Biological Methods

Regulations in many regions of the world require total phosphorus (TP) levels lower than 0.10mgP/L (100μgP/L) in effluents, resulting in the need to achieve very low ortho-phosphate (OP) concentrations. Chemical precipitation is a widely used technology for controlling effluent OP discharge, either on its own or supplementing biological methods. The various chemical and physico-chemical mechanisms that result in extremely low residual OP levels are complex and depend on pH. In practice, engineering calculations frequently use an empirical precipitation model. This model requires pH as input and predicts the lowest achievable OP residual of 35μgP/L at a narrow optimum pH of 6.9 – 7.0, when an excess of ferric is added. The model has been combined with a biokinetic and weak acid/base chemistry based pH model, to allow accurate prediction of pH, OP residuals and chemical sludge production. Analysis of effluent data from the Blue Plains plant shows that residuals as low as 10μgP/L OP can be achieved regularly, over a wider pH range. The precipitation model was recalibrated to match the newly available data. Subsequently it was compared with a new, mechanistic precipitation model based on solubility and dissociation constants for actual chemical compounds. The need for more accurate measurement of extremely low OP concentrations and considering the role of organics, adsorption and coagulation in chemical phosphorus removal is demonstrated.

scholarly journals A modified fouling index (MFI40) and fouling predicting approach for ultrafiltration of secondary effluents

2018 ◽  
Vol 9 (1) ◽  
pp. 67-82 ◽  
Author(s):  
B. J. Cai ◽  
I. Baudin ◽  
H. Y. Ng
Keyword(s):  
Standard Deviation ◽  
Treatment Process ◽  
Pilot Scale ◽  
Operating Pressure ◽  
Combined Effects ◽  
Positive Role ◽  
Secondary Effluents ◽  
Pre Treatment ◽  
Modified Fouling Index ◽  
Turbidity Increase

Abstract Fouling indices for evaluating fouling propensity of secondary effluents (SEF) as feed of ultrafiltration (UF) systems are important parameters for the design and operation of the UF process. However, limited fouling indices have been developed and applied for UF feedwater. This study (i) established a modified UF fouling index (MFI40) by raising operating pressure from 30 psi in a traditional MFI test to 40 psi. Standard deviation of MFI40 tests was lower than that of traditional MFI by 68.6%, indicating better stability and repeatability of MFI40. It (ii) investigated the combined effects of UF feedwater characteristics on MFI40. Biopolymers and turbidity played a dominant and secondary positive role in the MFI40, respectively. The effect of conductivity on MFI40 changed from positive to negative with a turbidity increase. It also (iii) validated the MFI40 in both laboratory- and pilot-scale UF membrane units, and UF fouling rates were linearly correlated to the MFI40 of their feeds, and (iv) explored the practical use of the MFI40. It was applied to determine the maximum allowable UF feedwater quality (MFI40max), which could be used to select an appropriate pre-treatment process. A fouling predicting model was established based on the feedwater MFI40 and the operating flux, with an average predicting error of 26.8%.

scholarly journals An overview of physico-chemical mechanisms of biogas production by microbial communities: a step towards sustainable waste management

3 Biotech ◽  
2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ramansu Goswami ◽  
Pritam Chattopadhyay ◽  
Arunima Shome ◽  
Sambhu Nath Banerjee ◽  
Amit Kumar Chakraborty ◽  
...  
Keyword(s):  
Waste Management ◽  
Microbial Communities ◽  
Biogas Production ◽  
Sustainable Waste Management ◽  
Chemical Mechanisms ◽  
Physico Chemical
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