Reverse Osmosis for water treatment

Published on by in Technology

Dear friends,

we want to ​treat our ​drinking water ​which we get ​from wells. ​

Which ​technology is ​best to use to ​desalinate ​the well ​water that has ​the 1000 ppm ​TDS level? The ​level of TDS ​needs to be ​lowered down ​to 200 ppm.​

Which method ​is more viable ​for this ​process, ​Electrodialysis ​Reversal (EDR) ​or Reverse ​Osmosis (RO)? ​

Share your ​points of view ​and please give ​some examples. ​

Taxonomy

13 Answers

  1. distillation under reduced pressure using a vacuum pump & solar panels? residue sold as salt if iron & arsenic etc. removed? 

  2.      Reverse Osmosis is a meaningless, excessive energy consuming process, using expensive high pressure pumps, expensive worthless membranes, and helplessly referring to micro pre-filters. Reverse Osmosis is an inappropriate process which is enforcing most worldwide sea shores to be left deserted due to the expensive equipment and expensive operation cost.

         Reverse osmosis is always coming with false claims of very low energy consumption, which correspond to new membranes, fouling of membranes will fade away these false claims after few days of using expensive membranes. The theoretical osmotic pressure for seawater is about 35 atm, while the actual osmotic pressure is 70 atm for new membranes, while after a month of operation the osmotic pressure is beyond 90 atm !!!???

         We would like to take the opportunity to present Natural Seawater Desalination as a magnificent process generating pure water out of seawater WITHOUT ANY ENERGY CONSUMPTION TO COMPLETE THIS SEPARATION. The energy needed to evaporate pure water from seawater is obtained by cooling the bulk of seawater, without any extra supply of energy. A process which is clear to every eye. It is a direct imitation of the natural process for the formation of pure rain water out of seawater.The equipment needed is very simple as the materials are not specified to withstand any high temperature or pressure.

        If interested please visit our website naturalseawaterdesalination.com

  3. We can desal and purify your water gallon for gallon.  We are not RO. We are less expensive than RO.  How many gpm do you need.  

  4. Reverse osmosis would be very effective at reaching specific levels of TDS but you would need to consider the potentially higher cost of running RO equipment (replacement membranes as well as operational energy costs).

    Also you would need to consider what to do with the reject water, which would have a TDS value of several thousand. Discharging to ground could eventually contaminate your aquifer, whereas discharging to a water body (river, lake, etc.) would likely cause environmental and ecological problems. Some of the reject water would be blended back into the treated water, in order to raise TDS back up to 200 ppm.

    I do not have professional experience of EDR, but my initial research suggests that it is primarily used for brackish waters (i.e. TDS of several thousand). Perhaps it might not be as effective as RO for reaching 200 ppm? Although I would be happy to be corrected by an expert in EDR.

  5. Hi Solmaz.

    Your question don't has a quick response. Firstly, you have to consider some points to define wich treatment fits properly to your water.

    In my opinion, some of these points are the followings:

    - Which kind of pollutants have you in your water? If they are apolar, without electrical charge, one EDI-EDR is useless, because that treatment works based on the attraction of the particles and its removal by their electrical charge. For example, if your main pollutant is silk, you will waste your money with the best EDI-EDR system but you won't remove anything.

    - If your pollutant are electrically charged particles. Which kind of charge do you have? Depends on the size of the molecule and/or its charge, it is possible that you could use a nanofiltration. RO remove all sized particules but sometimes are not needed such an aggressive process, and you can use a nanofiltration. The principle is the same, the pass through a semipermeable membrane, but in this situation, the cut is optimized to "big" molecules or divalent ones. If your main pollutant is SO4=, you can use this technology, that has a bit cheaper installation, but its clearly cheaper in its exploitation, becaouse it needs lower pressures than RO and therefore, less energy.

    - How big is your flow needed to supply? And the inlet stream flow? Consider that an EDR can have a conversion rate about 50% of inlet stream while RO conversion rate is among 65-80%.

    - Do you have enough energy for this systems? Which kind of energy do you have? Electricity?Thermal one? Biomass? Its cheaper in your situation boil water than apply a high pressure?

    - To end, have you consider other technologies as Forward Osmosis? It's a recently developed (

    1 Comment

  6. One of the things we do here, because we have a salt belt here. We use softening media.

    We do not put any salt in the brine tank and the softener removes the salt. We have successfully used this on wells that have over 1,000 ppm salt. It is a very simple solution to a complex problem. R/O removes everything and is very expensive to purchase and operate.

    Not a good way to treat water, no minerals left in water at all. This makes the water very aggressive if you don't add minerals to it.

     

    4 Comments

    1. Dear, Dear Contributors,

      Water softeners = Ion Exchangers are simply for exchange of ions. You will be exchanging a calcium, strontium, ... for a sodium ion. Then water will not be "hard water" rather it will be "soft water" as sodium salts do not deposit like calcium salts. In water softeners or ion exchangers there is no reduction in the amount of Total Dissolved Salts (TDS), as you have exchanged one ion for another one.

       

    3. Thank you Tim. May I ask what kind of softener do you use? I have the same problem! I just need to remove 50% of salt from water and RO is expensive for our case. 

    4. Many thanks Tim for your explanation, and if you can send us details of softening media:

      - Way of works,

      - Capacity of system per day (e.g. we have 2,000 individuals),

      - Operation and maintenance required, and

      - Cost estimate.

      - Compare with RTE method.

  7. Dear Ms. Adamaref,

     

    We are presenting to the worldwide community the best process to desalinate any saline water, which is Room Temperature Evaporation (RTE). RTE is the only physical phenomenon which does not need any supply of external energy, the energy needed to separate (to evaporate) pure water from saline water is simply supplied from the bulk of saline water cooling it. We are providing complete description of this process on our website www.naturalseawaterdesalination.com. We did not patent our design, and we made sure our design is fully described publicly to forbid any patenting to avail this design to everyone free of charge due the extreme importance of such an equipment for the welfare of the complete humanity.

     

    As our equipment operates at room temperature and pressure, then the materials of construction are less expensive and our final products are far less expensive than any of our competitors worldwide.

     

    Whether Reverse Osmosis, Electrodialysis Reversal, or any other similar process are suffering from complicated meaningless designs and expensive products. We are simply imitating the natural process of pure rain water formation, and this is the key of our success and leadership all the way.

    1 Comment

    1. Many thanks Maher, and if you can please send me details of RTE method: ​

      - Way of works, with documents

      - Capacity of system per day (​e.g. we have 2,​000 individuals, and if the water well TDS is 2500 ppm)​,

      - Operation and maintenance required, and ​

      - Cost estimate.

      - Can be implemented in remote area.

       

      My email is eng.mmzahem@gmail.com

  8. Depending upon what the contaminants in you well water, you want to design the system that removes only those contaminants and not the other minerals you need in your drinking water.  Normally you want to use a pretreatment for both RO and EDR to avoid plugging the membrane. These approach removes all dissolves solids. The difference between these two technologies is for RO you have the softener as part of its pretreatment that would require salt for regeneration and EDR reverses the polarity of electricity connected to the membrane to reject the removed ions.

  9. Water test result counts first. Use sediment filter 20',10' depending on level of sediments in the water, Water Softener(depending on water test result) and reverse osmosis  ( not just any RO - producer history counts). I can guarantee you Aquathin products. I use it for my well water.

    Simon 

  10. Hi,

    we have tunable technology based on dynamic capacitive deionisation technique for removal of TDS from water. It's chemical free and very low energy technology as compare to RO.

    thanks

    satish

  11. you don't want to just desalt it.  you need  to get a full spectrum analysis of your water and then match up the level/type of minerals you want to drink.  Its very important that you drink water with the required minerals as many are now coming to understand in the Middle East after a life time of drinking RO desal.  Lots of serious medical issues.

  13. Needs detailed chemical analysis for cat-ionic & An- Ionic Load to acertain better of the two.