It’s being billed as the largest project of its kind in the world and with 20 million inhabitants; it’s Mexico City’s bold plan to solve its massive drainage problems. The city’s new Eastern Wastewater Tunnel or ‘Emisor Oriente’ project, with a total length of more than 60km and a depth of up to 200m is valued at 650 million Euros (US $828.5).

S-497 EPB ready for delivery

Herrenknecht AG is providing three of the six EPB shields for this project with diameters of 8.7m and 8.89m. The first TBM, the 8.7m diameter Herrenknecht EPB shield S-497, has just been accepted by ICA Ingenieros Civiles Asociados at Herrenknecht’s plant in Schwanau, Germany.

During his visit, the CEO of the Mexican water authority CONAGUA, José Luis Luege Tamargo, witnessed the completion of the first TBM. "The Eastern Wastewater Tunnel is one of the most important water projects in the world, if we consider the investment volume, the length of the tunnel and the technology used," said José Luis Luege Tamargo. "The project will significantly reduce the risk of flooding in Mexico City and it will improve the safety and the well-being of the inhabitants and protect their properties."

"We are very proud that our tunnelling technology is part of this gigantic and internationally trail-blazing wastewater project, said Martin Herrenknecht. As part of this project, we can show how high-tech tunnelling technology is making it possible to build very efficient inner city tunnel constructions safely and precisely and without major inconveniences for those living in the city."

Mexico City takes delivery of TBM

The Eastern Wastewater Tunnel is to serve as an alternative drainage system in addition to the central tunnel. It has 24 inflow ducts at a depth of between 150m and 200m.

The project consists of 6 stretches with a total length of 63km and a planned inner diameter of 7m. The drainage capacity is 150m³/s on average.

The Eastern Wastewater Tunnel is part of a larger plan to improve drainage and replenish the City’s underground aquifers through an aggressive water conservation and recycling program along with the creation of new water supplies.

Due to historical overuse of its groundwater aquifers, causing soil subsidence of more than 10m, Mexico City’s can no rely on gravity to keep its city, of 20-million residents, from flooding.

Today more and more pumps are employed to drain the wastewater from the city. Between 1975 and 2008, the wastewater capacity of Mexico City’s drainage system has decreased by about 30%, from 280m³/s) to 195m³/s. At peak times, up to 315m³/s actually have to be drained.

The Valley of Mexico faces threats of strong flooding because of deficient wastewater ducts, the lack of alternative ducts and very heavy rainfall.

To solve the wastewater problems, the government of Felipe Calderón has launched a program, which aims to regenerate the water reservoirs in the basin of the Valley of Mexico: Less excessive use of groundwater reserves. Treatment of all wastewater. Exploitation of new supply sources. Construction of the Eastern Wastewater Tunnel to avoid flooding.

The first Herrenknecht EPBM is expected to arrive in port of Veracruz in April, from where it will be moved to Mexico City in a convoy of 40 trailers. Completion of the project is planned for September 2012.

Herrenknecht
CONAGUA Mexico's National Water Commission
Other TBMs headed to Mexico City