Effective chemical for reduce COD and maintain pH

Published on by

Hello everyone,

I observed that pH of wastewater is 8.1 and COD is 3492 mg/L, please guide me on how to reduce COD and pH shouldn't effect. Thanks

Taxonomy

8 Answers

  1. The first thing to look at is a BOD vs the COD; they do not necessarily follow each other.  It depends upon what the waste is composed of.  For example a high BOD with a low COD with a food produce vs a lower BOD and an high COD for a product from tannins from a lumber operation.   COD may have to be broken with an oxidizer such as Hydrogen peroxide, or chlorine.  A high BOD can be easily broken with bacteria cultures  - such as strains of Bacillus - along with air injection.

    However, the pH of 8.1 is OK, but on the high side of 8.2 for the best bacteria digestion.  Slightly lowered pH with a little acid can greatly improve bacteria digestion;  a 7.5 would be a great point to shoot for.

     

  2. Not enough information to work with. Don't even know what equipment you have to work with. Sure a strong oxidizer in the pipeline could do something.

  3. Let us know Source of water , Qty of water with detail Analysis of water , As COD is vague terminoloy  to offer you solution.

    Regards

    Amdy

     

  4. Put some chlorine and see the results.Looks like the water is stored for long time.

  5. All wastewaters are not the same or can be treated the same to get the desired end results. Please give more details as to its source, composition, flow, etc. which will help narrow the treatment options.

    Answered on by

    1 Comment

    1. Wastewater is from the metal industry

      1 Comment reply

  6. First of all specify the waste water source. Does it have heavy metals, cyanide or Cr6?

    Does it have extra chlorine??

    2 Comments

    1. Ok. So give the metals list. I duppose yiu git Iron. Check in a small scale, bring the pH to 9, and obsreve if you have any settlement. If so. You can bring the pH to 9 by cautic soda or lime, settle the waste, removecthe sludge and then aeration followed by a media filter (pp). The COD would come to the standard range, if didnt, make aersgion longer. After this process a filteration maintain the pH accorfing to your local demands.

      Good luck.

      1 Comment reply

      1. Let us go to the old time analytical chemistry where we really ran the pH up to get a lot of "stuff" drop out, including many metals.  This is still used as the lime/soda ash softening for large water softening in cities.  For the metal precipitation you may  need to goo well over 10.5, the point where we see free OH radicals forming.   You may well go to a 12 pH, but why spend the money when you may not need the excess to get the job done.  After the pH rise, a pH lowering (a a pH reversal)  to get the pH back down.   The information is not complete.  Metals industry?  If you are trying to separate precious metals, the pH reversal procedure will get most gold, silver, copper and nickel out - just not the final push to get the low levels to avoid some of the discharge requirements.  For the final push I have developed a material to get the final metals precipitated for recovery, and sale.  Most of our customers use it to do the final precipitation for nickel.

    2. Wastewater is from the metal industry