MIDLAND, MI – The Dow Chemical Co. (Dow) has finished the first phase of one of the most complex underground projects the company has undertaken in Latin America to date: the rehabilitation of the sewer pipelines in Mexico City. Mexican federal agencies identified Dow’s technical solution as one of the qualified options to renovate the pipelines. The first completed phase of the project covers approximately six kilometers of pipeline, while the total length of the pipeline to be rehabilitated is 120 kilometers, with a diameter of 5.5 meters.
The first phase of the project involved the application of a protective solution to refurbish the pipelines, which took place over a five-month period from Dec. 2008 to April 2009. The next step for the Mexican government is to wait for the end of the rainy season (May - November) to confirm the effectiveness of the completed work and select the suppliers of protective coating solutions. The project is scheduled to last until 2012.
“The pipes were in such a state of disrepair that we were concerned about the possible breakdown of the structure. Because of the work that we have done in this first stage of the project, we can guarantee the safety of the main drainage network,” commented the Director of Water Systems for Mexico City, Ramón Aguirre. “The completion of this project is a very important issue for the Mexican government,” stated Aguirre.
Constructed in 1975, with no regular maintenance since the middle of the 1990s, the sewer pipes in Mexico City have deteriorated to a point that the iron bars are exposed along the lines. For this project, Dow created a multi-layer anti-corrosion formulation that combines the extensive expertise and experience in both epoxy primer and polyurethane elastomer chemistry. First, an epoxy primer is applied directly over the concrete, followed by a layer of spray-applied polyurea elastomer. This solution offers excellent adhesion to the concrete, excellent resistance to the acidity of the tunnels, easy application, fast return to service (seven seconds drying time) and provides a harder surface, strengthening the pipelines.
“Dow’s extensive knowledge of polyurethane systems and epoxy coating solutions, combined with over 30 years of expertise in formulated systems, enabled the development of specific products to meet the needs of the Mexico City project,” said Juan Antonio Merino, General Manager of Dow Systems.