Chlorine Gas Overdose

If I add chlorine gas to the water at a dose that exceeds the required rate, how do I treat the water to decrease the concentration of chlorine in water? 

What are the efficient methods of mitigating the chlorine gas overdose?

Taxonomy

• Treatment Methods
• Chlorine Dioxide
• Water Treatment & Control
• Purification
• Chlorination
• Chlorine Dioxide Treatment
• Water Purification

28 Answers

1. SMBS dosing is the cheapest and most full proof conventional system. 

2. Simple and cheapest way is to expose the water to the Direct sunlight with thorough Aeration.

   Sodium thiosulphate can be used @ 0.75 ppm for 1 ppm residual chlorine 

    

   Ascorbic acid or Vitamin C can be used @ 1:1 ratio. 

    

   Activated carbon too can be used 

   it is more useful to reduce chlorine concentrations, Odorous, Chloramines (Carcinogens) and heavy metal & pesticides 

   1 Comment

   1. Nailed to perfection sir

3. Good morning,

   You can dose sodium Meta-bisulfite as a reductor, or use a GAC filtration as previously suggested.

    

4. Hi,

   leave it some time and concentration of chlorine automaticaly drop down. Speed of concentration decreasing is directly influenced by temperature and concentration of oxidable compounds (Mn2+, Fe2+, organic matter etc.). Dosing of any other chemicals (thiosulphate, Vitamic C, ...) is used in sampling procedure NOT in normal operation.  If you want to improve speed of de-chlorination, it is possible to use aeration.

   Ladislav

5. Perhaps ozone is more appropriate because it evaporates after cleansing ?

6. There are very good ascorbic acid (Vitamin C) based dechlorinating agents that are safer to use than many of the sulfiite based products. Here is link to one product that we use to dechlorinate backwash water before releasing back into a stream: www.vita-d-chlor.com

7. Sodium thiosulphate is the most effective chemical addative for chlorine reduction (FAC) in water

8. Activated Carbons transform chlorine to chloride without adsorption. Hence the life of the carbon bed is predicted very long with negligible running costs. However you will find chloride ions in your treated water

9. Hi,

   First of all, why should you overdose gas chlorine? there are many reasons why perhaps if you tell us more. Also, the two things we pay close attention to in the parlance of water treatment are quality and economy in other words achieving the desired quality with minimal waste or minimal amount of chemicals. Remember Chlorine is a carcinogen.

   Chlorine can and will  dissipate over time (especially gas chlorine) so one of your best bet is to allow it time to dissipate or if you're concerned with the taste it may give the water then pass it through activated carbon filters slowly..

    

10. Dechlorination in a fixed bed of granular activated carbon can help you as the activated carbon functions as a reducing agent. It is also functional to oxidize the mixture by shaking or in a cooling cascade. 

11. It is a general question and for this reason there are several answers. Please clarify your problem with more information. 

12. Wikihow suggests vitamin c tabs,and carbon filter

    1 Comment

    1. Thank you my friend

13. Campden tabs and pitcher filters for excess chlorine,but not effective against VOCs.

    1 Comment

    1. Thank you

14. Mohammed... Drinking water authorities usually add a slightly higher dose of chlorine before pumping it to the consumers. This ensures enough disinfection agent for those places that are far from the production site. Thus, it is a safer measure to guarantee that far consumers are protected from any disease causing microorganism. Chlorine may be lost from water with time and there is no need for the addition of chemicals to reduce chlorine. Thus, simple stirring is enough to reduce excessive chlorine in water.

    1 Comment

    1. What you're suggesting is chlorine in combined form called amines; it can be mono-chloro amine, di-chloro-amine etc It is usually not in excess and it's done to take care of any re-contamination in the distribution system due to leakage and suctions back into the pipe due to pressure loss for any reason.

       1 Comment reply

       1. Chloramines are a different thing to ensuring that there is an adequate free chlorine residual for disinfection. Chlor amines are not strong disinfectants and so it is usually important to disinfect with free chlorine and then convert to chloramine for distribution. Many operators prefer to ensure that the time part of concentration time multiple is maintained rather than making up for poor contact time with high chlorine.  

15. Following procedure to remove chlorine

    1. Boiling of the water
    2. Aerating it with plenty of oxygen.
    3. Activated carbon filter.
    4. ​Adding reducing agent.
    5. Adding sodium thiosulfate(Na2S2O3)

    https://www.youtube.com/watch?v=Uu8XQWdnZEs

     

    2 Comments

    1. I think you will find 4 and 5 are the same thing. Also, the oxygen does nothing in aeration. It is just gassing off and taking the chlorine with it.

    2. Thank you very much

16. In which kind of water treatment you did this?

     

    1 Comment

    1. I did this for drinking water in the final step of water treatment befor pump it to water net work

17. You can remove chlorine from your tap water by using a Granular Activated Carbon (GAC) filter that will absorb and trap most natural organic compounds, tastes, odors and synthetic organic chemicals.

18. Treatment methodology will depend on end use. For drinking applications aearation may be better or activated charcoal. For industrial use sodium metabisulphite may be better.

    1 Comment

    1. Thank you

19. Chlorine in water is reduced by adding a reducing agent. either sulphur dioxide as a gas or sodium sulphite or bisulphite as a liquid reagent. in an emergency situation or to reduce chlorine in water that is to be flushed to a watercourse solid sulphide chemicals can also be used. Adding a higher level and then reducing it after a contact time is a common practice, usually about 0.3 mg/l is left as residual for distribution though this depends on the nature of the distribution system. Alternatively you can use activated carbon to reduce it but be careful as this and the aeration others have suggested would then expose the water to contamination again.

     

    1 Comment

    1. You are nice man thank you

20. The demand for chlorine is probably due to residual oxygen demand or organics in the water stream. I would recommend taking a look at the processes producing the water being disinfected. You could probably optimize the upstream process to produce a cleaner water with fewer contaminants.

21. If this is drinking water I would use caution in using chemicals as this would create byproducts. A safe way to decrease the chlorine in the water is by aeration. 

    1 Comment

    1. If it is drinking water aeration will be not very effective and will allow contamination of water that has been disinfected

22. So2 or aeration on the acid side will do it depending on the overdose. All methods have drawbacks of their own.

23. You can dose sodium meta bisulphite (SMBS). It is used upstream of RO membranes to destroy any remaining free chlorine that can otherwise damage RO membranes.

24. How much of an over dose?  If not much just let it go. Or, you could add some sulfur dioxide to reduce some of  it. You could allow some chlorine to purge off if the excess does not react with the remaining TOC quickly.  You could add some ammonia to reduce the free chlorine while retaining distribution system residual.

25. Add sulphur dioxide in the ratio 0.9 SO2 : 1.0 Cl2 for each mg/l chlorine you wish to remove.

26. Dilute with more water

27. sodium thiosulfate will decrease the chlorine concentration.  use sparingly because sodium thiosulfate is a chlorine quenching agent.

28. You don't need to do anything as demand for chlorine in the water is so high that it would get consumed. The only issues would be higher corrosion of your pipes and heavy taste of chlorine in the water that consumers may detest.

    1 Comment

    1. It distribution network or house service connections are leaky and prone to contamination, better to be patient with excess chlorine so by the time the water reaches the point of use, the residual will be about 0.3 ppm. Still if there is need to reduce Cl2, simply choose aeration or activated carbon filter.