Economical Iron Removal from Water

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We have a deep well with the following water characteristics:

Apart from the reverse osmosis (RO) system, what other methods can be used for iron removal? What is the cheapest but efficient method?

I need to find an economical way of removing iron and the rest of the unwanted matter.  

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32 Answers

  1. RO membrane manufacturers specifications forbid iron concentration higher than 0.05 ppm in Feedwater. So, RO is not an option in your occasion.

  3. Two options:

    1.       you want  only to remove iron: in this case you must  to dose  an oxidizer such as sodium hipoclrorito and then filter the water through a multimedia filter. I believe that this is the most economical solution.
                        b.      You want to remove the iron and other salts: in this case the appropriate option is a RO    equipment. The ideal is that the water is sent directly from the well to RO equipment, with the least possible contact with the oxygen of the air

  4. An economical way of removing iron and other heavy metals is through the utilization of Activated Filter Media. This has been proven in research and independent testing by water utilities to produce 99% removal efficiencies down to 1 micron, >95% removal of Iron and significant reductions in chlorine usage and disinfection by-products (THMs).

    Information available here:

    https://www.waterandoilsolutions.com.au/active-filter-media

    I specialize in the use of this media in Australia and Asia where it is providing clean drinking water for millions of people.

    Please email me at andrew@waterandoilsolutions.com.au if you would like more discussion and information.

     

  5. The age old problem of iron in water is immediately remedied by the Aquathin Rust Sentry Iron Filter. For years, iron has caused deep, dark stain deposits in toilets, sinks, bathtubs, shower stalls, dishwashers, and icemakers. Only the frequent use of harsh acid-type chemicals and abrasive cleaners could reduce the stain deposits that would soon re-appear. The Aquathin Rust Sentry 2000 Iron Filter with it's powerful "potassium permanganate green sand filtering agent (KMnO4)", actively removes the iron and safely prevents staining. Often, the problem of iron is accompanied by dissolved manganese (blue-green or brown stains) and the rotten egg odor of hydrogen sulfide gasses. The Aquathin Rust Sentry 2000 iron Filter has the capabilities of removing these associated water problems while at the same time, acting on the iron. In areas where water contains decayed organic matter (humic acids or tannins) the Aquathin Rust Sentry 2000 Iron Filter is installed in conjunction with the Aquathin Soft & Clean Water Conditioner to prevent the shadow-type staining associated with tannins. Your Aquathin Professional Water Treatment Dealer is skilled in analyzing these situations in order to prescribe the correct system and installation settings.

  6. 2.63 mg/l will convert all the chlorine to chloramines which is poor at oxidizing Fe. The amount of cl2 required to break point chlorinate will be too expensive. While less cost effective a better strategy would be biological filtration with nitrification - denitrification and biological iron removal at the same time. The expensive part is getting enough dissolved oxygen to convert that much ammonia. 

  7. I think that adding chlorine will be more efficient to oxidize such level of iron  followed by a sand filtration

  8. The most economical method will be aeration followed by sand filtration. If your pH is low you must introduce soda ash or caustic soda  to increase water pH (to around 8).

  9. The best solution (technical/economical) for iron removal is related on the water flow. Can you specify it?

  10. Hello Thisara,

    First of all, it will be good to know what you are expecting as a result, in terms of treatment efficiency. 

    Second, if you want a really cheap system, you should use pH and oxygen levels to precipitate Fe3+ naturally. Then, you should also expect that other components will co-precipitate with it, reducing turbidity and Mn. 

    If you want a cheap treatment and you have space for the treatment system, I would propose a 3 step treatment : 1° adding air and ajusting the water quality + 2° precipitation chamber + 3° nitrifying and biological stabilization.

    If you like the idea, just send me an e-mail: xavier.gutierrez@nivachile.cl

    PD: it is very important to know pH/T°, O2 and TOC content.

     

  11. Aeration provides the oxygen necessary to change Fe++ into Fe+++ which is colloidal. The filtration (sand filters) after that removes the colloidal Fe+++. The best efficiency is achieved by spraying the water into a drum full of air (contact surface is enhanced). Some working pressure above atmospheric improves the solubility of air and the efficiency. The consumption of air is rather limited and therefore the compressed air make-up is not costly, but some air blow-down is recommended because the solubility of O2 is higher than N2 and the gas composition may become enriched by N2 after the preferential dissolution of O2 into the liquid phase

  14. Hi Thisara,  you may need to modify the pH with the application of aeration.  Higher pH (>6.5) will improve oxidation of iron.  The floc formed by the oxidation of iron may be sufficient to coagulate the turbidity, but you may also need to add an additional flocculant as it looks a bit low. Ammonia can be removed with clinoptillolite - a natural zeolite that is normally quite cheap.  Place a layer on your filters or a dedicated exchange column.  You may also want to try to identify where the ammonia is coming from (e.g. fertilizers, cattle pens, on-site sanitation) and then try to manage these to reduce the ammonia in the longer term.  The manganese is quite low, andnwill precipitate out with higher pH.

  16. Use aeration

  19. Hi there

     

    use sand filter and carbon filter after that do ultrafiltration or MBR and then start reverse osmosis.

     

    regards

    abdul gaffar - senior chemist

  20. We use an iron and manganese contactor to remove these constituents from the water. Iron and manganese comes out of solution from the water as precipitate and is filtered out of the water through injection of chlorine.

  24. As you do not provide details as to the end use of the water, I'll assume that it will be potable. For a very efficient way to precipitate all the Iron in the water, use CLO2 as a pre-oxidant. You'll clean out your system after a while and only a slight final dose of Chlorine will be necessitated to comply with EPA mandated residual levels in your distribution. System costs vary from a couple thousand to hundreds of thousands.

    1 Comment

  26. Lots of good ideas, but seems to me that you need to define the quality required and/or the end use for the water before attempting to prescribe solutions

  27. your best bet is aeration. The aeration method will depend on the flow you have and how your system is configured. pumping vast amount of air into an aeration tank can be costly (power) may be using a venturi could be effective.

  28. your best bet is aeration. The aeration method will depend on the flow you have and how your system is configured. pumping vast amount of air into an aeration tank can be costly (power) may be using a venturi could be effective.

  29. I would send this water into an aeration tank. lots of air stripping and some simple filtration will take care of most of your problems. However, the chloride will probably need r/o. The level it is at would not be too bad, but can create problems for piping and metals in your system.

  30. With all the ammonia you won't be able to use chlorine. Aeration often works but the pH will need to be >7.0. KMn04 is your next best option for oxidation and of course it will be followed by filtration. 

  32. As a primary answer you can easily remove Iron and Manganese using 20-50 ppm free chlorine and NaOH to achieve a pH 8-9 for oxidation following a sedimentation/oxidation tank for at least 1 hour residential time. Water should be then filtered by sand/pyrolusite media at a linear speed of 10 m/h. 

    1 Comment

    1. Oxidation followed by filtration is the cheapest way. If the flow is low, aeration followed by a good settling time and then filtration may solve the problem without chlorination. Oxidizer dosage can be calculated using Plutocalc.