Roberto Primelles

Technical Director - TICSA

“We are involved in BOT (Build Operate Transfer) projects for municipal wastewater treatment plants in Mexico. In the majority of these contracts, we are responsible for the operation of the plants for periods of up to 20 years. The biggest problem we have experienced with mechanical screens in the past is that the screens fail to perform as promised. Many screens we have used in the past have required continuous repairs and we’ve also had some cases where the screens had to be completely refurbished or even replaced after a very short time. As a result of this, and being BOT contracts, we have to absorb the cost related to the refurbishment/replacements of the screens, plus we also have to deal with any other costs which are a consequence of the screens’ improper work, such as clogging or even damages of equipment downstream. To make matters worse, the sewers in many parts of Mexico tend to bring all kinds of large and heavy items to the plants. The screens, being the first line of defense, have to be strong enough to not only cope with these items, but also to effectively screen them out and continue working. If you combine this with a 20-year operations contract, you can understand why we are so concerned about choosing the right screens.”