Re: Sewer Disposal & Plumbing

[melissa (M. Woo)]

Sorry that I'm not going to address your questions directly, Sue, but the
subject of sanitary sewage disposal reminded me of something that our
campus research reactor is currently facing.  I'm curious if anyone else on
the list has comments or whatever, as it has the potential to affect all of
us who maintain sanitary sewage disposal programs.

In order to prevent the discharge of insoluble radioactivity to the
sanitary sewage system, the NRC has "forced" (for lack of a better term)
our reactor to install filters in the discharge path for their retention
tank.  Apparently, the reactor has to use a 0.45 um filter, because (as
relayed to me by the reactor administrator -- I haven't seen anything in
writing) it would require a larger pile of paper to justify using a larger
pore size.

All of this bother is apparently a test case for the NRC, but if this
flies, one wonders about the ramifications for the rest of us.  Our campus
utilizes the method of sanitary sewage disposal of radioisotopes in order
to minimize the waste we must store.  I somehow can't imagine having to
install 0.45 um filters at every single outlet to the sanitary sewer from
campus laboratories.

According to 10CFR20 (Illinois regs in our case), the conditions of
discharge are that the "material be readily soluble, or is readily
dispersible biological material, in water."  How far does a lab, or rad
safety, have to go to determine solubility/dispersibility?  Where did NRC
get the 0.45 um pore size from?  Why do I foresee either a lot more work on
the horizon, or the possible cancellation of our sanitary sewage disposal
program entirely?

-- 
Melissa Woo                       | University of Illinois at Urbana-Champaign
Health Physicist                  | Environmental Health & Safety Bldg., MC225
office phone: 1.217.244.7233      | 101 S. Gregory St., Urbana, IL  61801
m-woo@uiuc.edu                    | http://www.cso.uiuc.edu/ph/www/m-woo