Boiler Chemical Cleaning Wastewater

Published on by in Technology

I have a project that requires to treat the boiler chemical cleaning wastewater which is high in COD.

The specification requests the oxidative process to be used to remove the COD. The client doesn't provide an additional basin to store the boiler chemical cleaning wastewater. It will be treated together with general wastewater from the power plant.

Can anyone help and advise what kind of oxidative process/chemical can be used in order to reduce the COD?

Taxonomy

17 Answers

  3. Dear W C L .. Best way is to use an RO system with heavy duty membranes to fix yr solids in them.. And by renewal the membranes can be attended. well wishes from Prof Ajit Seshadri. Vels University. Chennai. INDIA ..

    1 Comment

  4. Dear Wei,

    As I am sue you agree with me, not all the technologies can be used to solve all the problems. Even more there is not a unique solution to solve this problem.

    Before select which one is the best option in your case we must understaand all the problem.

    If you have a small area (or need a portable system), and need a simple and efficient operation, an AOP can be used.

    I suggest you considere the ozone becuse it can do the work in a simple way starting inmediatly, and even if you need it could digest to non detectable level (to transform in CO2 the COD if required), better than whatever biological system and with a better footprint performance (COD/m2).

    If you have a bigger and enought area, and time to start it,  you could invest in a complete or a more complex biological system to remove the COD. In some of this second option you will need special skilled people or remote control or in the worse case both, to operate the system.

    If you have a little more area, you can even construct a lagoon to treat it there.

    Of course the cost and election of each system will depend on the flow, COD and other parameters including Total Ownership Cost.

    In general terms:

    The biological systems have higher purchase cost and lower operation cost.
    The AOP systems have lower purchase cost and highest operation cost.


    Depending on the Total Ownership Cost and (ROI) evaluation you could select a combination of both.

    Regards,

    Orlando D. Gutiérrez Coronado

    1 Comment

    1. Your suggestion is very constructive. I will look into it. Do you have the experience using ozone for such kind of treatment?

      1 Comment reply

      1. Dear Wei,

        We can help you with your project, but before we would need know the lab analysis, and other valuable comments and suggestions as:

        - Flow and flow pattern (if you have irregular flow, as I suspect, you will need a equalization tank)

        - Maximum disponible area for the system.

        - Lab analysis includint (BOD, COD, TOC, and others).

        - Description of the system and process.

        - Removal requirement.

        - Others (description, suggestions, comments and important information for this project).

         

        I will wait for your answer.

         

        Regards,

         

        Orlando D. Gutiérrez Coronado

  6. Hello WEI CHOEW LEE,

    Advanced oxidation processes (AOP) such as ozone O3 would probably work on this kind of wastewater but VERY inefficiently at high operating cost because the generated free hydroxyl radicals OH° required to crack and oxydize the organic chemicals (high COD) will be scavenged by the minerals in this wastewater.

    Also just aeration with/without dilution would be very inefficient and take very long time because there far too little micro-organisms (if any) in this cleaning wastewater.

    Instead we use advanced biotreatment as the most  sustainable and efficient efficient solution achieving over 99% COD removal at low operating cost.

    Regards, Bruno

    1 Comment

    1. Hi Bruno, great to hear that. Can you kindly share your advanced biotreatment experience to my email wclee@organoasia.com. I would like to hear more about it.

  8. The reducing of COD depends on load, flow rates, the type of compounds and applicable discharge standards. When the COD consists of heavy metals only, one solution is to work with a physical-chemical treatment of water system ("flocculation") or a water treatment plant electrocoagulation. If the effluent does not contain hydrocarbon and volumes are significant (from 5 m3 per day), an excellent solution is the Nano filtration.

    An interesting solution is the treatment by chemical oxidation - oxidation-biochemical (biodegradation). If it is lightly loaded effluent, activated carbon can be an interesting solution.

    As to the reduction of BOD, it is done by biological processes.

    Hydrogen peroxide (H2O2) has been used to reduce the BOD and COD of industrial wastewaters for many years.While the cost of removing BOD and COD through chemical oxidation with hydrogen peroxide is typically greater than that through physical or biological means, there are nonetheless specific situations which justify the use of hydrogen peroxide. These include: Predigestion of wastewaters which contain moderate to high levels of compounds that are toxic, inhibitory, or recalcitrant to biological treatment (e.g., pesticides, plasticizers, resins, coolants, and dyestuffs);

     

     

     

  9. Please contact me with your contact information and I will provide you with NCNDA agreement so we can do business together on this matter, I have proven results in addressing this matter.  Bob  

  11. I do agree with most said, and it's important to get the water treated well, and it's crucial to get real-time insight of what's happening and when, as high COD can cause serious damage. Thus maybe continuous TOC(COD) monitoring is needed at some point. https://uk.hach.com/toc/family?productCategoryId=25114273658

    It's very important to have the pH right, and dosing too high O2 for aeration of water to remove COD needs control, as too much is a waste of energy, but also the C:N:P: ration is important for best COD removal. Thus, pls. consult with some of our local Power- or Waste Water consultants from Hach in your region, and also take a look closer to the solutions we've for all the water utilities in Power under https://uk.hach.com/power-overview 

    Bets of luck, trust this will do, and do not hesitate to reach-out.

  13. Dear My friend,

    Please share COD & BOD of the effluent generated from Boiler. Generally Boiler wastewater contain phosphate and inorganic pollutant. the pH will be higher side due to Sodium Hydroxide or other amine treatment. COD may be high due to presence of Sodium Hydroxide. Please share us analysis report of Effluent and Effluent quantity, so that we can give you viable solution.

    Thanks

    Vimalesh Patel, vimalesh.gci@gmail.com, 9376034476

    1 Comment

  14. Aeration is the simple solution

    Bubble service air in the effluent water till the bod reaches the limiting value

    1 Comment

    1. Client specify COD removal by oxidation agent while Fe removal by aeration. We are not sure whether only aeration itself will bring down the COD value from 500mg/l to 100mg/l.

  15. Greetings Wei,

    I agree with Nuno in the recommendation of using ph adjustments (from acidic to a ph of 10 or the reverse) to remove soluble materials from your boiler wastewater stream. Removing soluble material from just the backwash boiler flow will reduce the COD from your total wastewater stream. Treat at the source!

    Depending on the boiler backwash flow and your budget, find a small clarifier to separate solids from treated water.  This will allow you to remove solids containing most of the COD from ph adjustments. I also suggest doing a few lab samples with the boiler backwash/ wastewater to determine the amount of acid and caustic that is needed.

    Don't forget finding a way to dispose the solids too.

    Marcus         

    1 Comment

    1. Yes, agree on that if BCCW is mainly soluble iron or other metal waste. However, we are not sure whether the COD is caused by the cleaning chemical or soluble metals.

      1 Comment reply

      1. Ph adjustments with a little polymer will remove most metals. Lab test a small sample of your boiler backwash water using the ph adjustment method (you should observe solids forming when you change the pH of the boiler backwash water) then measure the COD of the boiler water without the solids in it to see how much the COD is reduced. Take a look at the pH of the cleaning/ scale removal chemical to get an idea where to start with adding acid or base.  Keep us posted with the results.   

  16. Hi. How much is the COD content? And the maximum flow and periodicity of the boiler ​cleaning? It will help to define the best treatment methodology. What's the pH, more acidic or alkaline? 

    Best regards, 

    Nuno Amaral-Silva

    1 Comment

  17. Will the BCCW be receiving any treatment prior to COD reduction? Arvia may hold the solution to your project's problem.

    1 Comment