Published
by Tamsyn Grewar, Senior Scientist at Mintek
We're looking for ways of cleaning up acid mine drainage, one of the issues we are facing is that our process produces sulphides that need to be removed downstream.
Does anyone know of a relatively cheap/simple way of removing sulphides from water?
We don't necessarily want to add expensive oxidants and the chemistry seems a bit complicated as the sulphides seem to revert to sulphate under certain conditions which would then mean we need to remove the sulphates too.
This is one of her specialties. We provide a new capital investment turnkey solution for acid mine drainage sulfide and/or iron removal technology. Please contact me for more information at 239-989-3581. Sean L. Roop USP technologies I Business Development Manager. Or visit www.usptechnologies.comandreferencemewhenyoucall in. I have 28 years of industrial wastewater experience, so I am more than adept at being able to help you technically as well as commercially.
This is one of her specialties. We provide a new capital investment turnkey solution for acid mine drainage sulfide and/or iron removal technology. Please contact me for more information at 239-989-3581. Sean L. Roop USP technologies I Business Development Manager. Or visit www.usptechnologies.comandreferencemewhenyoucall in. I have 28 years of industrial wastewater experience, so I am more than adept at being able to help you technically as well as commercially.
The chemical reactions don't stop at SO4...they continues, via a three step process, to form the H2SO4...sulphuric acid and that erodes infrastructure.
Hydrodynamic cavitation can aid in the remediation of mining waters. Please have a read of this recent presentation "Cavitation Technology Development: A Paradigm Shift in Mining Effluent Treatment" by the National Research Council Canada. I've been in contact with Deepak M. Kirpalani the Program Technical Leader - Effluent Treatment, EAM Program Energy, Mining and Environment and he has given me permission to share this with The Water Network community.
CaviMax design and build out hydrodynamic cavitation reactors and process intensification equipment. When you read the presentation, keep in mind that The CaviMax system is hydrodynamic cavitation produced by a rotor and stator. Please check out our website www.cavimax.co.uk our website is at present aimed at the biogas biomas disintegration sector, however, we will be updating it soon to reflect the variety of industries we are working in i.e. waste water treatment, sludge treatment, edible oil extraction, food waste disintegration to name a few. I hope we've given you more information for your appraisal and given you access to cutting edge information. Do get in contact with any further questions. Regards, Emma Greenwood
Hi Tamsyn, where is the AMD draining to: to surface water or groundwater? In case groundwater has been affected a possible option could be insitu anaerobic biological immobilization of SO4 by injecting an electron donor (for instance molasses) into the aquifer. I did pilot studies for mining sites in Chile with positive results.
for the removing sulphide you can apply the vetiver system that will be so cheap and best solution for treatment of water and its is the process that we plant the vetiver on there to remove contamination of water. hence if you need more information pls send me mail
The process of removing chemicals from the source is the responsibility of the mining company. They have to remove the chemicals they add from their processes. If no such law exists get the state government to pass one or get them replaced in the next election. Pick up the gloves and fight!
The obvious solution is to oxidize it to sulfate and precipitate out as a CaSO4.
Published
by Mark Spencer
1 Comment
In the question it was told that they don´t want to add expensive oxidants. Furthermore Sulphates cannot be precipitated as CaSO4 below a limit of appr. 1400 mg/l of ulphates. This mentioned amount would remain in the water. So this is not a good solution.
Dear Guido, what exactly do you mean by expensive oxidants ? Is O3 an expensive oxidant ? Have you ever calculated the cost of 1 kg/hr compared to others? Are non-oxidants less expensive than oxidants ? If yes please come-up with some real data.
Also you are talking about the solubility of CaSO4 in water. Actually the solubility at 20oC is 2.1g/l anhydrous and 2.4g/l di-hydrate. But when someones designs a precipetation system he/she uses the so-called COMMON-ION EFFECT. This effect will dramatically decrease the solubility of CaSO4 in water. Have you ever designed a precipetation system yourself ?
We have a simple innovative new technology that will help with this as done in numerous sulphide wastewater streams. The technology is called Magnetic Settling Catalytic Oxidation (MS-CATOXI). Check our website www.bluegoldholdings.co.za or contact me on khanya@bluegoldholdings.co.za
For stream water draining from a mine, the sulfide removal needs to be sustainably correct. I would start with ozone treatments. Pretty environmentally friendly treatment. Then if you are able to use bleach, it is cheap, but you have to be more careful isolating the water, treating it with bleach, then diluting the water with other sources of pure water or allowing the water to sit for a day or two , before releasing it back into the stream. I would use ozone.
Tamsyn - In cooperation with the mining industry in Northern Minnesota and the University of Minnesota, we have developed and field - tested a system that use naturally-occurring (Sulfate Reducing Bacteria) to removed Sulfates from mine-pit lakes - using floating bio-reactors. It is scalable and very low-cost. If interested, we can send you more details - Rob Scarlett
There several possible goals in reducing acid mine drainage. One goal is keep the sulphides from breaking down in to soluble sulfur which allows it to form the sulphates you mention. Another would be to capture as much of the sulphide bearing mineral and remove it if that is possible in your process? One method is to try to get the water as close to neutral pH as possible. Lime and/or limestone addition is a cheap way to do this.
Of course all this is very dependent on the chemistry of the minerals and water in your process.
Below are a couple articles on acid mine drainage.
May be you should treat your wastewater in a reed-bed based purification plant, but it must be one with a hight transfer rate of oxygen to the roots of the plants. Also special floating algae/sulfur-bacteria cultures are able to fix the sulfur. There is a huge reed-bed water purification plant in the Nimr oilfield in the south of the Sultanate of Oman, doing more or less the same. In case of any further questions, please contact my colleague Wolf-Dieter Rausch via .
Best regards Peter Niesslbeck niesslbeck@bioConsult-svi.de
Simple, low cost air oxidation will do the job, ranging from various simple outdoor spraying/fountain/cascading methods to fully enclosed stripping towers filled with raschid-type packing rings. Air-oxidation techniques will, as ever, depend on volumes, concentrations and money (and Capex v Opex budgets), and the release of bad-smelly, poisonous hydrogen sulphide gas into the atmosphere . Small volumes maybe environmentally dispersable/allowable, whilst larger volumes will require alkali absorption, and then correct disposal.
PH is critical. Fortunately you already have acid-pH, so simple air oxidation is cheap and acceptable - although you will need to adjust pH very carefully around 4.5-ish. Too low (~4.0) speeds up the oxidation reaction but is in danger of producing a sticky ppt of sulphur, whilst too high (~5.0) avoids the sulphur danger , but slows the reaction. ! A careful balance is required.
Basic thermodynamics using Pourbaix Diagrams (Eh v pH) will give you the answers.
I hope this helps you to understand the problem and its various solutions.
Published
by Nick Walton, Principal Lecturer at University of Portsmouth
Sulphides can be easily removed with bivalent Iron (Fe2+). Usually you dose Iron Sulphate (FeSO4). If you have a problem with discharging Sulphates too, you can also dose bivalent Iron Chloride (FeCl2). The bivalent Iron reacts with the Sulphide to FeS, which can be removed by sedimentation. For this process it is necessary to increase the pH value from acidic to neutral or slightly alkaline.