According to Paul Jacob who ...
Published by Bruno Peeters, managing director at Model Engineering
According to Paul Jacob who posted this article 2 years ago, the real issue of the poor design was the WRONG data. In his case, the sewage was diluted 5 - 10 times with rain or surface water. Unfortunately his case is quite typical for many STP (sewage treatment plants) designs. Even when using the best textbooks and software tools STP designs will fail when one feeds it with wrong data: garbage in = garbage out.