Mining effluent waters

MANAGEMENT OF PASSIVE BIOLOGICAL WATER TREATMENT SYSTEMS FOR MINE EFFLUENTS... 

The Pohla mine was the first to be flooded within the WISMUT project, and a water treatment plant was erected and put into operation in 1995. The neutral mine effluent, which is rich in bicarbonate (about lg/1), has an average flow rate of 17mVh and has undergone a marked evolution over time since flooding of the mine was completed. 

The high tension ion conduction agglomeration (INCA) system is an ex situ process for the recovery of soluble and particulate metals from aqueous solutions such as mining effluents, process waters, and wastewater. It is not known if the technology is currently commercially available. 

Tantalum is remarkably resistant to corrosion by acids, and is, in fact, referred to as a noble metal. It is not attacked by hydrochloric acid, nitric acid or aqua-regia, whether hot or cold, dilute or concentrated it is not attacked by hot dilute sulphuric acid, but boiling concentrated sulphuric acid dissolves it slowly. It dissolves in hydrofluoric acid, however, although when both metal and add are very pure, solution takes place only very slowly. A mixture of hydrofluoric add and nitric add attacks the metal rapidly, and in contact with platinum or carbon it is readily dissolved by hydrofluoric acid with evolution of hydrogen. Tantalum excellently withstands exposure to sea air, sea-water, sulphur dioxide, and mine effluents.1... 

Suspended Material. The material retained by the 0.45-pm membrane filters during filtration of the water samples collected from Ralston Creek and Reservoir was classified as suspended solids concentrations are shown in figure 4. The 226r3 content of suspended sediment in the mine effluent was 1,300 pCi/g U content of suspended sediment was 2,400 pg/g. Suspended-material load for this sample was 6 mg/L during the sample collection. Total release of both radionuclides (dissolved and suspended) was then calculated to be 8.4 pCi/L for 226r3 and 1,710 pg/L for U. Assuming an average daily... 

Most of the 226r3 associated with the suspended solids in the mine effluent probably is in the form of Ba(Ra)S04, because BaS04 is used as a decontaminant for 226r3 by the mine water-treatment plant. This evidence also is supported by the fact that little 226r3 in these suspended materials was leached by 2N HC1, as shown in the leaching experiments. Uranium probably is in the form of fine ore particles that are not settled out in settling ponds used in BaS04 treatment. 

Since these bacteria are aerobic, this scheme implies that an important function of oxygen is to provide oxic conditions for adequate respiration. These half-reactions (3 and 4) need not be in equilibrium with each other only a small amount of oxygen, enough for respiration, is necessary to drive this process. In this study, we are chiefly concerned with the reactions occurring in the effluent water after it has left the mines and has entered natural streams. 

Discharge of dewatering effluents from underground uranium mines and runoff from uranium mine tailings piles have contaminated surface waters and aquifers in New Mexico with elevated levels of gross alpha activity and uranium (NMHED 1989). The concentration of uranium in mine discharge water in New Mexico was 31,500 pg/L (equivalent to 22,680 pCi/L assuming the uranium content is natural uranium)... 

The relative proportions of arsenic species in estuarine waters are more variable because of changes in redox, salinity, and terrestrial inputs (Abdullah et al., 1995 Howard et al., 1988). Arsenic(V) tends to dominate, although M. O. Andreae and T. W. Andreae (1989) found increased proportions of As(III) in the Schelde Estuary of Belgium. The highest values occur in anoxic zones near sources of industrial effluent. Increased proportions of As(III) also occur near sources of mine effluent (M. O. Andreae and T. W. Andreae, 1989). Seasonal variations in concentration and speciation have been reported in seasonally anoxic waters (Riedel, 1993). Peterson and Carpenter (1983) reported a clear crossover in the proportions of the two species with increasing depth in the Saanich Inlet of British Columbia. Arsenic(III) represented only 5% (0.10 p,g L ) of the dissolved arsenic above the redox front but 87% (1.58p,gL ) below it. In marine and estuarine waters, organic forms of arsenic are... 

Nordstrom D. K. (1985) The rate of ferrous iron oxidation in a stream receiving acid mine effluent. In Selected Papers in the Hydrogeological Sciences. US Geol. Surv. Water-supply, paper 2270, pp. 113-119. 

CRAB Crabs/water 48 x 25 x 3 Individual/ location Elements Organ Center/scale Study the influence of mining effluents in water on the health of crabs... 

HPLC has also been applied to the analysis of trimethylolpropane and pentaerythritols in industrial synthesis solutions, 2-mercaptobenzothiazole in waste dump effluent, polythionates in mining waste water, isocyanates in working atmospheres, carcinogenic amines, aniline in waste water, polyethylene oxide fatty acid surfactants in industrial process waters and phthalate esters in river water. 

The acidity production can develop many years after disposal, when the neutralizing or buffering capacity in a pyrite-containing waste is exceeded. High concentration factors have been determined in inland waters affected by acidic mine effluents. 

Metals and metal finishing Mining effluent treatment Plating rinse water Reuse and recovery of metals... 

When triethylamine is used as an amine solvent or as a reagent, its relatively high water solubility (5.5% w/w at 20°C) leads to significant losses into waste aqueous streams and consequent higher costs for waste water treatment. Hiinig s Base, AT AT-diisopropylethylamine, on the other hand has relatively low water solubility (0.4% w/w at 20°C) and only dissolves 0.2% w/w of water in itself at 20°C. Hence mixtures of diisopropylethyla-mine and water readily separate into two layers yielding relatively dry amine for recycle. The waste water can be treated in normal effluent treatment plants without further handling. 

Reactions (1) and (2) are usually catalyzed by iron-oxidizing bacteria (such as Acidithiobacillus ferrooxidans, Leptospirilum ferrooxidans, or Ferrimicrobium ssp.) which increase the oxidation rate by up to 10 over the abiotic rate [2-5]. Field and laboratory studies have shown that the ferrous iron dissolved in mine effluents is normally oxidized at rates of between 10 and 10 (average 10 ) mol s [2, 5, 19, 20], These rates depend on factors like (1) water temperature, (2) dissolved oxygen content, and (3) density of bacterial populations. The iron-oxidizing microbes are usually present at numbers of 10 -10 mL [4, 19, 21]. 

Heavy metal-laden effluents arise from mine drainage water, surface drainage and mill process waters. The most common treatment method is to discharge the wastes to a tailings pond in which the pH is controlled within the range 9.5 to 10.5. A minimum retention of 5 days is recommended with a pond of 4 to 11 ha for each 1000 tonnes of solids discharged per day [20]. A well controlled tailings pond can achieve effluent lead concentrations of 0.1 mg dm . ... 

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