Denitrification of High-Strength Industrial WW

[wardens355]

I am looking into biological treatment of wastewater produced at a coal plant. The plants produces 0.4 MGD wastewater with 1700 mg/L NO3-N and virtually no COD/BOD. This stream must be treated down to approximately 25 mg/L before being blended and released. My rough estimate for an anoxic basin requires ~560,000 gallons of tankage, HRT ~35 hours, 2000 gallons per day methanol. This seems like a rather substantial investment, and since I cannot find similar applications, I am thinking there must be a better way to tackle this issue.

Has anyone had experience with removing extremely high nitrate wastewater, biologically or otherwise? I haven't been able to find similar applications and am thinking a pilot study would be a good option. The facility should probably look into minimizing the amount of nitrate it introduces to the waste stream, but has anyone ever heard of a power plant producing wastewater with > 1500 mg/L NO3-N? Any thoughts would be appreciated.

 

[QualityTime]

Can you make a deal with the municipality to dump the waste into their sewage treatment plant via a sewer pipe? There would most likely be a surcharge to your sewage rates

 

[ckeller]

I see the "-N" on there, but are you certain the results are being reported "as N"? If they are reporting "as NO3" then the "as N" concentration is more than 4 times lower (or about 400 mg/L). Regardless of whether the reporting units are correct, it is still a high loading and carbon is likely very limiting. You might also look at a passive system (biofilter, constructed wetland, reactive barrier) that either has organic media by design or creates dissolved carbon (wetland) to reduce the supplemental C requirements.

 

[wardens355]

The report listed ~7500 mg/L as nitrate, I converted to nitrate-N. If the plant wants to move forward I will keep a passive system in mind. 1700 mg/L NO3-N may be a touch high for a passive system to be practical, but I am not terribly familiar with passive systems for nitrate removal.