Removal of Sulphides from Wastewater

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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.

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37 Answers

  1. 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.  

  2. 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.  

  3. s02 = so4

    aeration tanks which helps to covert so2 to so4 its a simple way to reduces so2 and other organic and inorganic compounds.

    1 Comment

    1. 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.

  4. HI Tamsyn, 

    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

    1 Comment

    1. When we complete our phase two pilot operation we will target H2S...remove the hydrogen and send it  through PEM Fuel Cells to generate electricity.

  5. 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.

    If interested I could send some info.

    Best regards, Jaap van Nes

     

  6. Hi 

    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

    stagenpl@gmail.com  

  7. 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!

  8. make a tank which capcity of tank you need fill the water which contain so2 and bottow surface of tank fixs the air inventor(air diffuser).

    And if your is water is black treat the water by cogulatants and remove s04 by below decribe procedure

    1.cogulants- lime alum and poly electrolyte.

    lime is use to increase the pH which helps to settle the suspend particle

    alum is as some but it helps to reduces pH and remove color from water

    and poly for quick settling .

     

    and if you need in cheap 

    just to remove so2 you may bulit a tank and in botttom surface fix the air diffuser.

  10. The obvious solution is to oxidize it to sulfate and precipitate out as a CaSO4.

    1 Comment

    1. 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.

      1 Comment reply

      1. 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 ?

  12. Here are two articles for you.

    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.

     

    https://www.google.com/search?q=removal+of+sulfur+from+water&sourceid=ie7&rls=com.microsoft:en-US:IE-SearchBox&ie=&oe=&gws_rd=ssl

    http://www.spartanwatertreatment.com/hydrogen-sulfide-removal.html

     

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  13. 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

  14. Hello,

    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.

    http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.595.4733&rep=rep1&type=pdf

    https://brownfieldstsc.org/pdfs/amdinnovativetrttech_03.pdf

     

    There are also bio-remediation methods using bacteria for removing sulpides as in the article below.

    https://clu-in.org/download/studentpapers/S_Doshi-SRB.pdf

     

  16. 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

  19. 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.

     

  20. 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.

    I hope I could help you with my answer.

  21. You might like to oxidize the sulfide into sulfur, using a catalyst. You will have a sulfur product stream, however, no chemicals consumption.

  23. Good day, Tamsyn.  If you have the full details, ie. volumes to be treated, standard you want met after treatment and so forth, please contact me on james@nuwaterglobal.com I can run a complete mass balance for you and advise exactly whats needed.  Do you have budget allocated for this project as yet?  NuWater has extensive mining experience treating such streams as you have to either discharge limits specification or even for re use in process.  Let me know.  Contact number is +27 82 803 1010

  24. If you SO3 concentration is less than 208 mg/lit then oxidising them to SO4 gives you no problem as the limit for SO4 is 250 mg/lit. Oxidising is the only clean and sure way of getting rid of SO3 without any undesired by-products.

    Of course it all depends on your water flowrate.

    There is a wide choice of oxidants but I would personally use ozone as any residual O3 reverts naturally to O2 within a certain time limit.   

    3 Comments

    2. Hi George,

      I completely disagree. It is but one solution and now outmoded by biotechnology.

      Regards,

      Dr. Wayne Sampey

      1 Comment reply

      1. Hi Wayne, so is CHEMISTRY outmoded ???? There is a lot of discussion about biotechnology lately so it has become like the cell phones, everybody has got one !!!!!

  25. Hello Tamsyn,

    We use specific microbes capable converting sulfides into elemental sulfur. Our main application is in sewer lines and wastewater treatment plant to prevent H2S formation but I am sure these would also could help you if operating conditions would be favorable for bacterial development. Sent me an e-mail on r.wagenveld@qmes.nl and I can forward additional info.

  27. There is a nice, cheap and natural way to do it, using naturally occurring sulphur oxidising bacteria (SOB).  I have attached a link to a paper on the subject. 

    http://www.acenz.org.nz/uploads/Events/INNOVATE%20Projects/29.%20Wairakei%20Bioreactor%20-%20webprofile-edited%20by%20HM.pdf

    and

    https://www.youtube.com/watch?v=XZD0h9rgiRY

    It basically just uses long lengths of pipe with a bio-film and uses no energy and was very effective.  In fact it was the Global Winner for the Design Projects Category of the 2014 International Water Association (IWA) Global Project Innovation Awards Competition with the award presented in Lisbon.  I know the design engineer very well and can put you in touch if interested.

    1 Comment

  30. Abstract

    The biological oxidation of hydrogen sulphide by aerobic  Thiobacillus -like bacteria has been described. The hydrogen sulphide is oxidised into sulphur particles which are in the submicron range. The colloidal properties of these sulphur particles are compared with those of a standard LaMer sulphur sol. The biologically produced sulphur particles are composed of a core of elemental sulphur covered by a layer of natural charged polymers, presumably proteins. The polymer layer renders the particles hydrophilic. Colloidal stability can be attributed mainly to steric repulsion. Although the electrokinetic charge is always negative with varying pH, the point of zero charge is found at pH 5.8. This indicates that the polymeric molecules are oriented with their negative charges to the bulk solution. An expanded-bed reactor was developed in order to stimulate the aggregation of the sulphur particles into large, well-settleable sulphur flocs with a diameter of about 3 mm.

    Keywords

    • Sulphide; 
    • Sulphur; 
    • Bacteria; 
    • Sedimentation; 
    • Waste water; 
    • Natural gas

  32. Rakesh, only Group 1 & 2 metals form soluble sulfides (probably do not occur in acid mine drainage), the rest are insoluble. I am assuming that the sulfide moiety we are mainly dealing with is dissolved H2S. This can be precipitated or immobilized as Iron sulfide or free sulfur as long as the acidity has been neutralized with lime or limestone. The acid insoluble "heavy metal sulfides" are valuable & maybe worth recovery. I do not think it is a good idea to degas as H2S is so toxic.

    Answered on by

  33. Under the right conditions, you can precipitate native sulfur which will need to be periodically harvested or it could revert back to sulfate. See the Eh-pH diagram for sulfur. However, as suggested below, iron can be used to sequester sulfur as a metal monosulfide.  The problem is, treatment with this method in perpetuity is unsustainable.  Have you looked at bactericides for ARD source control?  The method was pioneered 30 years ago and has sadly fallen off our remediation radar.  I'm trying to reverse that trend.  Good luck.

  34. Metal sulfide are insoluble, so I presume that you are using sulfide to precipitate the metals and now you have dissolved sulfide left in the water. What is the pH since sulfide can be neutral as dissolved hydrogen sulfide gas or as sulfide ion?

    if the pH is low, which means that most of the sulfide is neutral, then we can degas the hydrogen sulfide gas

     

     

  35. Iron ore. Fe2O3 + 3H2S = 2FeS + S + 3H2O

    You would have to replace the iron ore every so often. The iron sulfide could be regenerated by roasting but the SO2 + SO3 generated would have to be trapped as H2SO4 or CaSO4. Another way would be to add sodium bisulfite: SO2  + 2H2S  = 2H2O + 2S  

    Answered on by

  36. You have limited choices, you can precipitate it (lime or some other chemistry) or you can oxidize it and filter it (more chemicals). All removal options produce a waste that needs to be dealt with. If you look into IX or electro/capacitive DI you still have a waste stream to deal with with a concentrated mineral content. The IX/Cap-DI will also give you a bunch of other inorganic components to deal with as will precipitation. No easy answer.

  37. Hi.

    Did you think already of some ion-exchange processes? Or e.g. zeolites? Obviously this might be only feasible as a downstream process in WWT.

     

    Regards,

    R

    1 Comment

    1. Hi Tamsyn,

      The efficiency of biological processes using organisms (bacteria) depends on local circumstances. This means you would have to control and monitor (24x7) environmental circumstances, such as temperature, pH, pollutants. If you are using "ACID mine ​drainage" water, bacteria may be unsuitable.  

      A more expensive, but more RELIABLE method, could be using reversed osmosis. This does require a lot of energy (electricity) and it gives you pure water (other salts are also removed). It does not need much space, even for large capacity. Both small and large devices are available. In Holland these machines are used in commercial horticulture to remove surplus salts from water, so the water can be recycled for growing plants. To save budget consider buying a second hand reversed osmosis system. Contact lenntech.nl for more info.

      Note: The amount of sulphates on earth is limited; it is being overexploited. Therefore, sulphates may offer you a source of income (in future). This may help you to develop a solid financial plan.