LuizSousa
The below search for pipeline coating will give you a number of references and companies involved in pipeline coating, cleaning and repair.
DDT
http://search.msn.com/preview.aspx?&q=pipeline+coating
There was a lot of work performed on this problem during the 80s at the nuclear plants. It started because of biofouling (clams/mussels) but when the problem was looked at in more detail MIC was also a big problem. You should get the system cleaned (mechanically and/or chemically)...