Ammonia removal from wastewater

[Rolf]

Wastewater contains 1000-5000 mg/l NH3, and must be reduced to <10 mg NH3/l for discharge. What methods are available? Raising pH and air-stripping is one obvious solution, but then the off-gas will have to be oxidised to remove the ammonia gas and this will require fuel, scrubbing and recycling. The wastewater is in a large tank. Can it be treated in situ?

 

[qshtr]

I was working on a similar problem. I didn't find any other solution than the one that you described. It was wastewater from coking plant containing mainly NH3 and H2S, some cyanides and other compounds. The idea was to strip volatile compounds with steam at high pH and catalyitic cracking of off-gas in reactor at high temperature. The reaction products are going back to coke gas.

If you need any more info about this, let me know.

Regards,

qshtr

 

Quite easy to solve. Try looking at the standard Waste Water Treatment processing practices for Nitrification/Denitrification which are:

1. Combined carbon oxidation nitrification/denitrification in suspended growth reactor using endogeneous carbon source.
2. Combined carbon oxidation nitrification/denitrification in suspended growth using waste carbon source.
3. Suspended growth using methanol following a nitrification stage.
4. Attached growth (column) using methanol following a nitrification stage.

If you want a commercial proposal, please pass on your request to our VP Operations Les Smyth at lsmyth@tgeng.com

Courtney Dehn
Process Manager
TG Engineering Inc.
Calgary
Alberta
Canada

http://www.tgeng.com

 

[tblaser]

Rolf:

You have a fairly concentrated source of NH3. Do you have enough volume of wastewater to economically recover the NH3 and sell it or make other products?

Tim

 

[gkandy]

Why not try steam stripping ? This will generate ammonia liquor which you can recover back in the system.

 

At that high level of concentration nitrification would be difficult. I would try the steam stripping to get most of the ammonia out and then maybe nitrification.

 

[spekuljak]

A suitable method is ammonia stripped with air, circulating in a close loop, in two columns. One of them is Stripping column, and the other is Absorber column, i.e. with an acid solution (sulfuric, clorhidric, fosforic) to obtain the salt (fertilizer), and avoid to exhaution of ammonia to atmosfere and do not incorporate carbon dioxide from fresh air, which produces solid deposition (carbonatation) on column internals.
Other way is steam stripping, in a column with a short rectification section, to obtain amoniacal solution, i.e., 25 - 30%
Sp.

 

[NagusAlex]

Gentlemen,

For a new ammonia removal technique, visit

http://www.thermoenergy.com

and follow the threads to download a peer reviewed report.