Here is a link to articles I came across during a search on 'salt in septic tanks'.
http://www.google.com/#hl=en&sugexp=ldymls&xhr=t&q=salt+water+in+septic+tank&cp=15&pf=p&sclient=psy&rlz=1R2SKPB_enUS357&source=hp&aq=0sx&aqi=&aql=&oq=saltwater+in+se&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=c933f7452b4afda8">http://www.google.com/#hl=en&sugexp=ldymls&xhr=t&q=salt+water+in+septic+tank&cp=15&pf=p&sclient=psy&rlz=1R2SKPB_enUS357&source=hp&aq=0sx&aqi=&aql=&oq=saltwater+in+se&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=c933f7452b4afda8</a>
I will summarize by saying these two things:
1) the sudies seem to suggest it is not a problem for either the bacteria or the soil in the drain field.
2) I'm on a a septic tank, and will not put saltwater into the system. Why?
-A) Considering the cost of repair, and what I know about the bacteria in septic tanks, it's not worth it, IMO.
-B) The Roman's 'salted the soil' of enemies they really disliked. Doing so ruins the soil for generations. I feel that I have a greater responsibility.
-JMHO