Artificial circulation of a mine pit lake

2015 ◽  
Vol 42 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Roger Pieters ◽  
William Coedy ◽  
Ken I. Ashley ◽  
Gregory A. Lawrence
Keyword(s):  
Oxidation Process ◽  
Saline Water ◽  
Open Water ◽  
Circulation System ◽  
Artificial Circulation ◽  
Pit Lake ◽  
Ice Melt ◽  
Mine Pit Lake ◽  
By Products ◽  
Snow And Ice Melt

We describe the artificial circulation (destratification) of a pit lake at the Colomac mine site, 220 km north of Yellowknife, NWT, Canada. The pit lake, with a surface area of 17 ha and depth of 110 m, contained relatively saline water contaminated with the mining-related cyanide by-products, thiocyanate and ammonia. As a result of snow and ice melt, the pit lake was intermittently meromictic and cycling of contaminants through the oxygenated surface layer would have taken many years. To accelerate the oxidation process, the pit was artificially circulated using two air diffusers at a depth of 57 m. The pit lake was circulated during the open-water season, from 12 July 2006 for 57 days, and from 17 June 2007 for 89 days. After the first 12 h of operation of the circulation system, the top 37 m of the pit lake was mixed completely; after 34 h, the pit lake was mixed to the depth of the diffusers (57 m); and after approximately 6.5 days, the pit lake was mixed to the bottom. Upon complete mixing, the temperature and conductivity remained uniform during operation of the circulation system, and the concentration of oxygen in the deep water of the pit lake increased significantly. All thiocyanate was oxidized by the end of the first summer, producing ammonia that was depleted after the second summer of circulation.

scholarly journals Fate of Diclofenac and Its Transformation and Inorganic By-Products in Different Water Matrices during Electrochemical Advanced Oxidation Process Using a Boron-Doped Diamond Electrode

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1686 ◽  
Author(s):  
Carolin Heim ◽  
Mohamad Rajab ◽  
Giorgia Greco ◽  
Sylvia Grosse ◽  
Jörg E. Drewes ◽  
...  
Keyword(s):  
Current Density ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Early Stage ◽  
Advanced Oxidation ◽  
Target Compound ◽  
Duration Of Treatment ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
By Products

The focus of this study was to investigate the efficacy of applying boron-doped diamond (BDD) electrodes in an electrochemical advanced oxidation process, for the removal of the target compound diclofenac (DCF) in different water matrices. The reduction of DCF, and at the same time the formation of transformation products (TPs) and inorganic by-products, was investigated as a function of electrode settings and the duration of treatment. Kinetic assessments of DCF and possible TPs derived from data from the literature were performed, based on a serial chromatographic separation with reversed-phase liquid chromatographyfollowed by hydophilic interaction liquid chromatography (RPLC-HILIC system) coupled to ESI-TOF mass spectrometry. The application of the BDD electrode resulted in the complete removal of DCF in deionized water, drinking water and wastewater effluents spiked with DCF. As a function of the applied current density, a variety of TPs appeared, including early stage products, structures after ring opening and highly oxidized small molecules. Both the complexity of the water matrix and the electrode settings had a noticeable influence on the treatment process’s efficacy. In order to achieve effective removal of the target compound under economic conditions, and at the same time minimize by-product formation, it is recommended to operate the electrode at a moderate current density and reduce the extent of the treatment.

scholarly journals Theoretical study of ice cover phenology at large freshwater lakes based on SMOS MIRAS data

2018 ◽  
Vol 12 (8) ◽  
pp. 2727-2740 ◽  
Author(s):  
Vasiliy Tikhonov ◽  
Ilya Khvostov ◽  
Andrey Romanov ◽  
Evgeniy Sharkov
Keyword(s):  
Brightness Temperature ◽  
Open Water ◽  
Ice Cover ◽  
Freshwater Lakes ◽  
Ice Melt ◽  
Bear Lake ◽  
Ocean Salinity ◽  
Satellite Microwave ◽  
Transportation Routes ◽  
Temperature Time

Abstract. The paper presents a theoretical analysis of seasonal brightness temperature variations at a number of large freshwater lakes: Baikal, Ladoga, Great Bear Lake (GBL), Great Slave Lake (GSL), and Huron, retrieved from Microwave Imaging Radiometer with Aperture Synthesis (MIRAS) data (1.4 GHz) of the Soil Moisture and Ocean Salinity (SMOS) satellite. The analysis was performed using the model of microwave radiation of plane layered heterogeneous nonisothermal medium. The input parameters for the model were real regional climatological characteristics and glaciological parameters of ice cover of the study lakes. Three distinct seasonal brightness temperature time regions corresponding to different phenological phases of the lake surfaces: complete ice cover, ice melt and deterioration, and open water were revealed. The paper demonstrates the possibility to determine the beginning of ice cover deterioration from satellite microwave radiometry data. The obtained results can be useful for setting the operating terms of winter crossings and roads on ice, as with the beginning of ice deterioration, these transportation routes across water bodies (rivers, lakes, water reservoirs) become insecure and cannot be used any more.

scholarly journals Elucidation and Characterization of New Chlorinated By-Products after Electrochemical Degradation of Hydrochlorothiazide Using Graphite–Poly Vinyl Chloride Electrode

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 540
Author(s):  
Zainab Mussa ◽  
Fouad Al-Qaim ◽  
Ali Yuzir ◽  
Hirofumi Hara ◽  
Shamila Azman ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Treatment Process ◽  
Oxidation Process ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Experimental Conditions ◽  
E Coli ◽  
Flight Mass Spectrometry ◽  
Negative Ionization ◽  
By Products

This paper describes an electrochemical treatment process of hydrochlorothiazide (HDZ) under different conditions such as initial concentration, sodium chloride and applied voltage. In this present study, HDZ was treated by electrochemical oxidation process using graphite-PVC composite electrode as anode and Platinum (Pt) as cathode. All results were analyzed using liquid chromatography-time of flight/mass spectrometry (LC-TOF/MS). It was found that at high applied voltages, and high amounts of NaCl, the electrochemical treatment process was more efficient. The removal% of HDZ was 92% at 5 V after 60 min. From the obtained results, the electrochemical oxidation process of HDZ followed pseudo first order with rate constant values ranged between 0.0009 and 0.0502 min−1, depending on the experimental conditions. Energy consumption was also considered in this study, it was ranged between 0.9058 and 5.56 Wh/mg using 0.5, 0.3 and 0.1 g NaCl within interval times of (10, 20, 30, 40, 50, 60, 70, and 80 min). Five chlorinated and one non-chlorinated by-products were formed and analyzed in negative ionization (NI) mode during the electrochemical process. Due to the strong oxidizing potential of the chlorine (Cl2) and hypochlorite ion (ClO−), HDZ and its by-products were removed after 140 min. Furthermore, a novel synthesis of chlorothiaizde as one of the new by-products was reported in this present study. Toxicity was impacted by the formation of the by-products, especially at 20 min. The inhibition percentage (I%) of E. coli bacteria was decreased to be the lowest value after 140 min.

Degradation of carbamazepine by UV/chlorine advanced oxidation process and formation of disinfection by-products

2016 ◽  
Vol 23 (16) ◽  
pp. 16448-16455 ◽  
Author(s):  
Shiqing Zhou ◽  
Ying Xia ◽  
Ting Li ◽  
Tian Yao ◽  
Zhou Shi ◽  
...  
Keyword(s):  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Advanced Oxidation ◽  
By Products

Influence of chloride ions on organic contaminants decolorization through the Fe0-activated persulfate oxidation process: efficiency and intermediates

2019 ◽  
Vol 80 (3) ◽  
pp. 563-574 ◽  
Author(s):  
Feng Ding ◽  
Yong Xie ◽  
Tengyan Wu ◽  
Na Liu
Keyword(s):  
Organic Contaminants ◽  
Oxidation Process ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Transformation Products ◽  
Chloride Ions ◽  
Process Efficiency ◽  
Persulfate Oxidation ◽  
By Products ◽  
Activated Persulfate

Abstract This study was conducted to evaluate the influence of chloride ions (Cl−) on organic contaminants decolorization by the Fe0-activated persulfate process (PS/Fe0), as well as the generation of transformation products. Orange II (OII) was chosen as the target pollution. The results indicated that Cl− influenced the OII decolorization by PS/Fe0 system, resulting in the generation of chlorine-containing by-products. OII containing Cl− solution can be efficiently decolorized by PS/Fe0 process, and the decolorization efficiencies changed depending on Cl− concentration due to the reaction between Cl− and sulfate radicals (SO4–•). The operating cost for 94% color and 64% chemical oxygen demand (COD) removal of the OII dye was estimated at 0.73 USD/m3. The chlorine-containing by-products, such as chlorobenzene, 3,5-dichloro-benzene-1,2-diol, and 2,3-dichloro-2,3-dihydro-1,4-naphthoquinone, were generated during the reaction. The results further indicated that increasing both PS concentration and temperature enhanced OII decolorization and reduced the generation of chlorine-containing intermediates. The addition of ultrasound can further decrease the generation of chlorine-containing intermediates under high-temperature conditions. The proposed pathways of decolorization of OII containing Cl− also indicated that SO4–• dominated the OII degradation, while the presence of Cl− led to the generation of chlorine-containing intermediates.

scholarly journals Characteristics of Chromophoric and Fluorescent Dissolved Organic Matter in the Nordic Seas

2018 ◽  
Author(s):  
Anna Makarewicz ◽  
Piotr Kowalczuk ◽  
Sławomir Sagan ◽  
Mats A. Granskog ◽  
Alexey K. Pavlov ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Sea Ice ◽  
Chlorophyll A ◽  
Saline Water ◽  
Atlantic Water ◽  
Nordic Seas ◽  
Ice Melt ◽  
Fluorescent Dissolved Organic Matter ◽  
West Spitsbergen

Abstract. Optical properties of Chromophoric (CDOM) and Fluorescent Dissolved Organic Matter (FDOM) were characterized in the Nordic Seas including the West Spitsbergen Shelf during June–July of 2013, 2014 and 2015. The CDOM absorption coefficient at 350 nm, aCDOM(350) showed significant interannual variation. In 2013, the highest average aCDOM(350) values (aCDOM = 0.30 ± 0.12 m−1) were observed due to the influence of cold and low–saline water from the Sørkapp Current in the southern part of West Spitsbergen Shelf. In 2014, aCDOM(350) values were significantly lower than in 2013 (av. aCDOM(350) = 0.14 ± 0.06 m−1), which was associated with the dominance of warm and saline Atlantic Water (AW) in the region, while in 2015 intermediate CDOM absorption (av. aCDOM(350) = 0.19 ± 0.05 m−1) was observed. In situ measurement of three FDOM components revealed that protein–like FDOM dominated and concentration of marine and terrestrial humic–like DOM were very low and its distribution were generally vertically homogenous in the upper ocean (0–100 m). Fluorescence of terrestrial and marine humic–like FDOM decreased in surface waters (0–15 m) near the sea–ice edge by dilution of oceanic waters by sea–ice melt water. The vertical distribution of protein–like FDOM was characterized by a prominent sub–surface maximum that matched the subsurface chlorophyll a maximum and was observed all across the study area. The highest protein–like FDOM fluorescence was observed in the Norwegian Sea in the core of warm AW. There was a significant relationship between the protein–like fluorescence and chlorophyll a fluorescence (R2 = 0.65, p 

scholarly journals Evaluating the impact of climate on snow- and ice-melt dynamics in the Taillon basin, French Pyrénées

1997 ◽  
Vol 43 (145) ◽  
pp. 563-568 ◽  
Author(s):  
David M. Hannah ◽  
Glenn R. McGregor
Keyword(s):  
Large Scale ◽  
Energy Budgets ◽  
Computer Assisted ◽  
Air Masses ◽  
Atmospheric Circulation Patterns ◽  
Ice Melt ◽  
Circulation Types ◽  
The Impact ◽  
Snow And Ice Melt ◽  
Snow And Ice

AbstractThis pilot study adopts a computer-assisted synoptic typing methodology to evaluate the totality of climatic influences on snow- and ice-melt dynamics within a small cirque basin in the French Pyrénées. The synoptic categories identified possess contrasting large-scale atmospheric circulation patterns and surface energy budgets which generate differential ablation responses. Continental air masses yield consistently high melt. Advection of moist maritime air also produces elevated but more variable ablation due to air-mass transitions. The two observed local valley circulation types show melt to be higher under nocturnal katabatic drainage than for anabatic wind flows associated with development of daytime ridge-top cumulus.

The effects of phosphorus additions on the sedimentation of contaminants in a uranium mine pit-lake

2005 ◽  
Vol 39 (13) ◽  
pp. 3055-3061 ◽  
Author(s):  
Tarik C.E. Dessouki ◽  
Jeff J. Hudson ◽  
Brian R. Neal ◽  
Matthew J. Bogard
Keyword(s):  
Uranium Mine ◽  
Pit Lake ◽  
Mine Pit Lake
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