Challange to treat industrial ww

[appy1]

Hi there,

We are facing problem of very high NH4-N concentration in our effluent stream from chemical plant. On the contrary, there is no organic carbon source in the waste stream. If we gonna implement activated sludge treatment process, we need to add external carbon source and thats costly affair for us. can anybody knows alternative treatment process for this.
Wastewater flow = 10 m3/hr
NH4-N concentration = 12 mg/l
COD conc < 100 mg/l

Appreciated any hints
Thanks in advance

 

[mbeychok]

appy1:

First, let me say that by my terms of reference, 12 mg/l (i.e., 12 ppm by weight) is not a high NH4-N concentration and 10 m3/hr (i.e., 44 gal/min) is a fairly low flow rate of wastewater.

You could investigate using ion exchange to remove the ammonia, followed by some means of converting the effluent ammonia to nitrogen or nitrogen oxide (perhaps by incineration).



Milton Beychok
(Contact me at www.air-dispersion.com)
.

 

[appy1]

Thanks Milton,

But my concern is if we can treat by activated sludge treatment process. Nitrifiers are slow growing bacteria, that converts NH4-N into NO3-N. and if sludge wastage rate is minumum,i.e SRT is infinitive, can we get ride of NH4-N. I am doubtful as COD< 100 mg/l.

Please respond

 

[bimr]

Low levels of organic carbon in the wastewater would lead one to select attached-growth nitrification reactors because it may eliminate the need for clarification following the nitrification process. You should investigate the use of a RBC.

A suspended-growth activated sludge nitrification reactor is probably not practical because it will be difficult to control the solids inventory in the activated sludge process.

Other process to look into would be air stripping, breakpoint chlorination, or ion exchange.

Air stripping will involve high operating and maintenance costs because you need to have a high pH (11) to convert the ammonia to a gaseous form before air stripping of the ammonia. Then, you need to be concerned with the salts precipitating in the air stripper. Probably not feasible.

Breakpoint chlorination requires a CL2 to ammonia (as N) stochiometric mass ratio of 8:1 so it is expensive.

Ion Exchange is very, very, very expensive because of the extensive pretreatment that is required prior to the ion exchange units. Pretreatment is to prevent fouling of ion exchange resins.

Your best option for physical treatment is probably breakpoint chlorination. Good Luck.