During their studies at the University of Wismar, two of our interns were able to gain experience abroad in Ecuador. The two of them actively supported our rehabilitation project in Guayaquil for eight months.
Lisa Schwegmann and Shezad Singh reported on their experiences in Ecuador in BDB Landesspiegel 4/2018:
German engineers in action worldwide
Civil engineering students from Wismar in Ecuador
A current project of the company Ludwig Pfeiffer Hoch- und Tiefbau GmbH & Co. KG is the rehabilitation of the wastewater protection area La Chala in Guayaquil, Ecuador. The residential area in the La Chala basin stretches along the river Guayas. The area is at sea level and below the groundwater level, which is why the entire remediation work is exposed to the tides.
Due to the extensive damage to the canal network, large infiltrations occur. The rehabilitation should ensure a significant reduction of infiltrations and enable the sewage treatment plant to manage the wastewater discharge adequately.
This project is currently one of the largest trenchless rehabilitation projects in the world and is financed by the World Bank. The scope of the project consists of cleaning 120 km of pipeline and carrying out a sewer inspection as well as rehabilitating approximately 90 km of sewer and approx. 400 shafts. The dimensions range from DN150 to DN1300.
Three different technologies are used for the rehabilitation of the sewer network:
CIPP liner with UV curing
The use of different technologies and the mentioned range of diameters make this project unique and very interesting.
For the CIPP technology, a factory-fabricated glass fibre liner impregnated with resin is drawn into the sewer to be rehabilitated, set up with air pressure and then cured with UV light. Depending on the dimensions of the old pipes, the UV light chain is adjusted accordingly. The diameter and the statically required wall thickness are decisive characteristics for the duration of the curing process. Due to the existing conditions, a certain individuality is created for this technique alone.
The other two processes are mainly used for smaller dimensions in this construction project. Renos’ ® special short pipe relining process is used for short pipe lengths of up to 15 metres. Renos short-tube modules are manufactured from the raw material PP (polypropylene) by injection molding. Before the new pipe can be inserted into the existing pipe, it is electrically welded together. Despite the small change in cross-section, the hydraulic capacity remains due to the good flow properties of the plastic. Thanks to the quick and easy installation, this process is very efficient and cost-effective.
Burst lining is only used in Guayaquil when a collapse or major damage such as holes or large cracks occurs in the existing pipe and GRP hose relining (CIPP) is not technologically applicable. In this case, the old pipe cannot be used as a base and is destroyed and expanded by means of burst lining. In this process the fragments are displaced into the surrounding soil. The new pipe is drawn in at the same time through the resulting channel.
From the point of view of construction students, the experience that can be gained in such a project is enormous. In comparison to Germany there are many other problems, which arise and must be considered. Also the social conditions in a country like Ecuador differ a lot from Germany, for example the construction works are constantly accompanied by security personnel and there are always people in the employment, which are immediately operational in case of accidents.
Delivery and import problems also influence the work on site. The time difference of seven hours plays a major role in communication with German companies and employees. Therefore, conversations and telephone calls with German companies are only possible in the morning until about 10:00 a.m. Ecuadorian time. In addition, there is a close e-mail contact in order to reduce the time problems as much as possible and still maintain the contact.
All in all, working on site offers a great opportunity for young engineers to gain experience such as the range of different technologies and the different problems compared to Germany.