Wastewater Mercury Removal? 2

[waynef43]

I am looking for a process to remove mercury chloride from wastewater streams generated from the treatment of flue gas at a coal fired plant.

Are there any known processes and should the mercury in this wasterwater stream even be an issue?

I don't have any concentration data and am looking at issues passed to me by management that may arise in the forseeable future.

Thanks for the help.

 

[bimr]

Mercury is one of those compounds where there is a "fear factor" associated with it (like asbestos) and where it is also possible to detect extremely small amounts in water. With those elements, one can be sure that mercury will be an issue.

To remove mercury, sulfide precipitation is a reliable technology that is capable of meeting extremely low discharge requirements. Siemens has a FGD treatment scheme presented in the link below that utilizes sulfide precipitation.

There are other mercury technologies such as resins, carbon, etc. My understanding is that sulfide precipitation is probably the best technology.

Bench and pilot testing will be critical for the success of an application.

http://www.water.siemens.com/en/pow...gas_desulfurization_wastewater_treatment.aspx

http://www.degremont-technologies.com/IMG/pdf/tech_infilco_FGD-Mercury.pdf

http://www.ncsafewater.org/Pics/Tra...s/AC10_SpecialTopics/ST_M.AM_11.00_Cooper.pdf

 

[DZCLE]

Precipitation technologies may be limited in their ability to reach discharge limits that are less than 20 ppt. Adsorbent technologies like resins, carbon, and other engineered materials may be able to reach those low ppt levels. One such engineered material is manufactured by MAR (

http://marsystemsinc.com/).

Economics would determine if it is better to use these technologies as a primary or polishing process step after precipitation.

I agree with bimr that bench and pilot testing is critical for success in this type of application.

 

[bimr]

Siemens has been successful in removing mercury to less than 20 ppt with sulfide precipitation. Precipitation is not a standalone technology, it is used in combination with filtration and other technologies.

One of the problems with wastewater treatment is disposal of the residual materials. This is less of a problem with sulfides as the sulfides are relatively stable. Most of the metal ores found in nature are actually in the sulfide form.

 

[waynef43]

Thanks to both of you. I believe this gives me the information that our management team desires.