Pilot-scale neutralisation of underground mine water

1996 ◽  
Vol 34 (10) ◽  
pp. 141-149 ◽  
Author(s):  
J. P. Maree ◽  
G. J. van Tonder ◽  
P. Millard ◽  
T. C. Erasmus

Traditionally acid mine water is neutralised with lime (Ca(OH)2). Limestone (CaCO3) is a cheaper alternative for such applications. This paper describes an investigation aimed at demonstrating that underground mine water can be neutralised with limestone in a fluidised-bed. The contact time required between the limestone and the acid water, chemical composition of water before and after treatment, and economic feasibility of the fluidised bed neutralisation process are determined. A pilot plant with a capacity of 10k1/h was operated continuously underground in a gold mine. The underground water could be neutralised effectively using the limestone process. The pH of the water was increased from less than 3 to more than 7, the alkalinity of the treated water was greater than 120 mg/l (as CaCO3) and the contact time required between mine water and limestone was less than 10 min (the exact contact time depends on the limestone surface area). Chemical savings of 56.4% can be achieved compared to neutralisation with lime.

2019 ◽  
Vol 19 (1) ◽  
pp. 9-20
Author(s):  
J. K. Obosu ◽  
J. S. Y. Kuma ◽  
W. K. Buah

The Tarkwa district is an important gold mining area in the Southwestern part of Ghana. The main source of potable water supply to the Tarkwa Nsuaem Municipality is from the Bonsa River treatment plant managed by the Ghana Water Company Limited (GWCL). The River is under threat from serious contamination by illegal mining ("galamsey") activities within its catchment area. Consequently, the amount of water supplied to the Municipality has not kept pace with its growing population due to increasing treatment cost and supply difficulties. The need to find alternative and sustainable sources of potable water supply to augment that from GWCL to the Municipality has become imperative. A large void volume created as a result of the abandoned underground mine operated by Gold Fields Ghana Limited (GFGL), after its closure in 1999 has flooded. This potential water resource is being pumped out daily, and wasted, sometimes spilling-over to low lying areas around the mine when allowed to reach its decant level. This study estimated the quantity of water in the Abontiakoon Vertical Shaft (AVS) which is part of the large underground void using survey production figures and post-closure void filling parameters resulting in 2.8 x 106 m3 and 2.9 x 106 m3 respectively. The rate of recharge to the underground water was also estimated to ascertain the sustainability of the void water should it be considered for use by employing the model of predicting rebound on “void filling” basis and average dewatering rate before closure at 2 535 m3/day and 2 618 m3/day respectively; indicating that recharge to the AVS reservoir is about 6 x 106 gal/day or 30% of current daily water supply deficit in the TNM. The estimated potential volume of mine water in storage in the entire Tarkwa underground void is 32 x106 m3. Two samples of the mine water were taken in November 2011 and February 2015 for quality analysis, in order to have a fair knowledge of the water quality parameters. The quality of the underground water was found to be potentially good, and not likely to cause any health threats, or water quality problems. Depth sampling is recommended to determine the chemical profile of the reservoir. Keywords: Reservoir, Municipality, Bonsa River, Contamination, Tarkwa


1994 ◽  
Vol 29 (9) ◽  
pp. 285-296 ◽  
Author(s):  
J. P. Maree ◽  
P. du Plessis

Traditionally, lime is used for the neutralization of acidic effluents. Calcium carbonate should be considered as an alternative because of considerations such as lower cost, low solubility at pH values greater than 7 and simple dosing system required. The paper describes a pilot scale study to determine the technical feasibility of neutralising sulphuric acid-rich water using fluidised bed technology. Limestone was utilised completely when testing iron(III)-rich water, but with iron(II)-rich water, coated limestone particles accumulated in the fluidised-bed reactor. About 70% of the limestone was utilised in the case of water containing 600 mg/l iron(II). A contact time of 4 min was sufficient for the neutralization of acid water containing 4 g/l free acid and 580 mg/l iron(III), compared to 40 min when iron(II) replaced iron(III).


2012 ◽  
Vol 532-533 ◽  
pp. 455-459
Author(s):  
Qiu Qin Lu ◽  
Guang Qiu Huang

In order to study behaviors of underground mine water inrush spreading, the multiple-phase LBM based on finite-volume particles and point-particles applied to create the LBM-Lagrange simulating model of underground water inrush spreading with silt. The simulation result shows that the model can get the visual information of water-sand inrush speed, water-sand pressure and distribution of water-sand phase. Therefore some effective alternatives can be made to control underground mine water inrush.


1992 ◽  
Vol 26 (7-8) ◽  
pp. 1769-1778 ◽  
Author(s):  
S.-I. Lee ◽  
B. Koopman ◽  
E. P. Lincoln

Combined chemical flocculation and autoflotation were examined using pilot scale process with chitosan and alum as flocculants. Positive correlation was observed between dissolved oxygen concentration and rise rate. Rise rate depended entirely on the autoflotation parameters: mixing intensity, retention time, and flocculant contact time. Also, rise rate was influenced by the type of flocculant used. The maximum rise rate with alum was observed to be 70 m/h, whereas that with chitosan was approximately 420 m/h. The efficiency of the flocculation-autoflotation process was superior to that of the flocculation-sedimentation process.


2021 ◽  
Vol 410 ◽  
pp. 128438
Author(s):  
Xiaoli Zhu ◽  
Pengfei Dong ◽  
Zhiping Zhu ◽  
Raffaella Ocone ◽  
Wuqiang Yang ◽  
...  

Author(s):  
Nurul Huda Osman ◽  
Nurul Najiha Mazu ◽  
Josephine Liew Ying Chyi ◽  
Muhammad Mahyiddin Ramli ◽  
Mohammad Abdull Halim Mohd Abdull Majid ◽  
...  

This paper reports on chitosan/bentonite crosslinked (ChB-ECH) film for removal of Cu (II). The effects of chitosan/bentonite ratio on the removal percentage were studied along with the effect of different Cu (II) concentration and the contact time on the film adsorption capacity, qt. The electrical properties of the film are studied, before and after the adsorption occurred, by using impedance spectroscopy for different parameters such as DC conductivity, the complex dielectric constants (ε’ and ε”) and complex electrical modulas (M’ and M’’). The results showed that the chitosan/bentonite ratio of 3:1 produces highest removal percentage at 29 %, while the contact time of 120 minutes was found to be optimum. An increment in the DC conductivity of the ChB-ECH film’s was observed up to 10-7 S/cm as the removal percentage of film increased. The film with the highest Cu (II) adsorb also showed the highest value for ε’ and ε” while exhibiting non-Derby behavior. Shifting of peak amplitude of the M” towards the higher frequency was also observed as the Cu (II) adsorption in the film increased. The results showed that all the electrical parameters can be utilized to determine the amount of adsorbed copper (II) in chitosan/bentonite film.


1998 ◽  
Vol 38 (12) ◽  
pp. 109-117 ◽  
Author(s):  
V. Lazarova ◽  
M. L. Janex ◽  
L. Fiksdal ◽  
C. Oberg ◽  
I. Barcina ◽  
...  

Advanced disinfection processes (peracetic acid, UV irradiation and ozonation) have been tested and evaluated through bench and pilot scale studies. 3 log removals of total coliforms, faecal coliforms and faecal streptococci were achieved by 10mg/L peracetic acid at a 10min contact time, by UV radiation at 35mW.s/cm2 and by ozone at 5mg/L for 10min contact time. Higher doses are required for virus removal by UV and PAA and especially for highly resistant viruses such as F-specific bacteriophage MS2. Ozonation has the advantage of having a strong effect on all types of bacteriophages and protozoa cysts even when low treatment doses and short contact times are applied. The results of this study demonstrated that evaluation of disinfection efficiency of ozone, UV and PAA depends on the criteria and methods employed. Standard method (plate count) results showed an important disinfection effect on culturability, while results from non-standard methods (respiratory activity and β-galactosidase activity assay) indicated less reduction of viable cells. Moreover, the results confirm that disinfectants act on bacteria in different ways. It has been clearly demonstrated that b-galactosidase activity is affected by PAA while UV treatment has no or very limited effect on the enzyme activity. Even without sunlight reactivation, bacterial regrowth in seawater was observed after disinfection of sewage effluents. This study also shows that the biodegradability of sewage effluent for an E coli strain was affected differently by the oxidative disinfectants ozone and PAA. Biodegradability should therefore be considered when evaluating the total disinfection efficiency.


1992 ◽  
Vol 25 (2) ◽  
pp. 291-298 ◽  
Author(s):  
B. Koch ◽  
J. T. Gramith ◽  
M. S. Dale ◽  
D. W. Ferguson

A pilot-scale study of ozone and PEROXONE (ozone in combination with hydrogen peroxide) for the removal of the odorous compounds 2-methylisoborneol (MIB) and geosmin in drinking water has been conducted at the Metropolitan Water District of Southern California. The study investigated the effects of ozone dosage, ratio of hydrogen peroxide to ozone (H202/03), and contact time. It was found that MIB and geosmin removal increased with higher applied ozone doses, but longer contact times over the range of 6-12 min were not significant. It was determined that 80-90 percent removal could be achieved with an ozone dose of approximately 4.0 mg/l, as compared to an ozone dose of approximately 2.0 mg/l at a H202/03 ratio of 0.2. Also investigated were the effects of alternative contactor configurations, ferrous sulfate as an alternative coagulant, bromide and ammonia addition, and simulated turbidity on the removal efficiencies of the two odorous compounds.


2002 ◽  
Vol 283 (6) ◽  
pp. H2431-H2439 ◽  
Author(s):  
Tomoko Kamishima ◽  
John M. Quayle

Mitochondrial Ca2+ uptake is usually thought to occur only when intracellular Ca2+concentration ([Ca2+]i) is high. We investigated whether mitochondrial Ca2+ removal participates in shaping [Ca2+]i signals in arterial smooth muscle over a low [Ca2+]irange. [Ca2+]i was measured using fura 2-loaded, voltage-clamped cells from rat femoral arteries. Both diazoxide and carbonyl cyanide m-chlorophenylhydrazone (CCCP) depolarized the mitochondria. Diazoxide application increased resting [Ca2+]i, suggesting that Ca2+ is sequestered in mitochondria. Over a low [Ca2+]i range, diazoxide and CCCP slowed Ca2+ removal rate, determined after a brief depolarization. When [Ca2+]i was measured during sustained depolarization to −30 mV, CCCP application increased [Ca2+]i. When Ca2+ transients were repeatedly evoked by caffeine applications, CCCP application elevated resting [Ca2+]i. Caffeine-induced Ca2+ transients were compared before and after CCCP application using the half decay time, or time required to reduce increase in [Ca2+]i by 50% ( t ½). CCCP treatment significantly increased t ½. These results suggest that Ca2+ removal to mitochondria in arterial smooth muscle cells may be important at a low [Ca2+]i.


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