Removal of an organic acid salt from waste water

[lsu003]

First, let me say that I am a long time reader and appreciate the insight given on these forums.

A little background: Our sister plant is in the process of building a new production line to produce a certain type of polymer. An extruder has already been installed to do a majority of the drying of the polymer. However, in recent trials we have been unable to run this type of polymer on the Anderson due to frequent die plugs. In an effort to avoid plugging, we used a carboxylic acid to terminate the polymer. The carboxylic acid was neutralized after termination using NaOH. This seemed to solve our plugging problems; however,BOD, COD, and Oil/Grease tests on our waste water shot up to well over our permit limit.

It appears that the sodium salt of the carboxylic acid is highly soluble in water and must be removed. Does anyone have any ideas on methods to remove this chemical from the water, i.e. could bugs be used to digest this material? Our working idea is to add sulfuric acid to the water. Since it is a stronger acid, we should be able to regenerate the carboxylic acid and extract it out using hexane.

The new reactor line should be coming online with in 6 months so we are under pressure to figure this out before then. If anyone has heard of other methods or has comments on our proposed method, I would appreciate.

Thanks again. I look forward to being able to post more often.

 

[lastone]

Try PALL Filtration Corporation out of New York. They have some new technologies in their membrane filtration that might be suitable for your application.

Another option might be using a small Lamella type clarifier with a flocculant to precipitate the salt and dispose of as a sludge.

 

[epoisses]

use an ion exchange resin

 

[moltenmetal]

The answer to your question greatly depends on which carboxylic acid you're talking about. Can you tell us? If not, good luck to you- anything might work, or nothing.

 

[lsu003]

2-Ethylhexanoic Acid

 

[bimr]

Persistence and Biodegradability:

This product is estimated to have a moderate (>= 30%) rate of biodegradation in a test for ready biodegradation.

The general recommendation is that de minimis amounts from say an equipment washdown or very minor leaks may be washed down to the sewer. Concentrated quantities should be collected and sent offsite for disposal.

In general, if your wastewater treatment facility is of significant capacity and handling similar chemicals, this particular chemical should not be present a problem. If this is the only chemical in your plant, it may pose a problem to the wastewater treatment facility.

 

[mbeychok]

lsu003:

You will need to neutralize the stream containing the sodium salt of the carboxylic acid down to about a pH of about 5 to match the pH level of the Oil and Grease lab test. That means that you should give some serious thought to the materials of construction in your neutralization section.

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