At 09:34 AM 2/13/00 -0900, Kelly wrote:
>A refrigeration line blew leaking ammonia into the water system of a
>surimi processing factory. On a contaminated belt and inside a piece of
>machinery, he found a hard white 'pasty' substance which was not easily
>removed (came off with scraping). He drained, flushed, and refilled the
>water tanks, but he is not convinced that the ammonia is completely
>removed. He is getting pH's on his distilled water between 9.2 to 9.5. His
>concerns are as follows:
>- What will neutralize the ammonia
All ammonium salts are very solution. Ammonia can be removed easily with
any acid cleaner or weak acid, such as acetic or citric. Acetic acid has a
strong odor, but citric is fairly corrosive. Use mild solutions.
You can also leave a pail of weak acid in the room for an extended time to
clear the ammonia, which outgasses.
>- How can he be sure the ammonia is removed from the water
Ammonia forms a base with water (NH4OH). If the rinse or swab water is pH <
7 (determined via pH meter or dye indicator), the ammonia is gone for all
practical purposes.
There are also NH3 electrodes for pH meters, but they are costly and
complex to use.
>- What could the white 'pasty' substance be and might it be within the
>piping
Probably built-up hard-water scale which was unnoticed until this time. It
can also be removed with acid cleaners. Or protein scum, which again is
susceptible to acid cleaners.
>- If it is within the piping, will it continue to be picked up in the
>water flow, contaminating further
It would show up immediately in the outflowing water by odor and pH.
Otherwise levels are acceptable.
>- What will the ammonia do to the surimi
It will be possibly absorbed into the top layer, affecting odor and taste.
>- What, if any, levels of ammonia are safe (i.e., if there is ammonia in
>the water used to process surimi)
Ammonium salts are safe. Except for undesirable odor or corrosive vapors
and high pH when present in great excess, ammonia is not a hazard. The
issue is more one of offensive odor or color, or presence of vapors to
irritate worker's lungs.
PS. If fish muscle pigments have not been removed, color changes will occur
and it will be very difficult to eliminate the ammonia at that point.
================================================================
Robert A. LaBudde, PhD, PAS, Dpl. ACAFS e-mail: ral@lcfltd.com
Least Cost Formulations, Ltd. URL: http://lcfltd.com/
824 Timberlake Drive Tel: 757-467-0954
Virginia Beach, VA 23464-3239 Fax: 757-467-2947
"Vere scire est per causae scire"
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