efe-epaMexico City

The daily burning of 4,500 tons of urban solid waste over three decades in Mexico's capital would violate domestic environmental protection laws and an international treaty the Aztec nation signed, experts who reject a plant to be built for that purpose said Wednesday.

They expressed concern that in April Mexico City's Urban Management Agency awarded a unit of French group Veolia, Proactiva Medio Ambiente, a 30-year contract to build a thermo-valorization plant that will produce electricity for the capital's 12 metro stations.

The plant, which will be the first of its kind in Latin America and begin operating in 2020, will generate power by burning 4,500 of the nearly 13,000 tons of urban solid waste the metropolis generates daily.

Thermo-valorization is a process that uses heat to decompose inorganic waste, while the vapor that comes from the decomposition is used to generate electricity and the remaining solid waste can be used in the construction industry.

But Raul Sergio Cuellar, Mexico City's solid waste technical director from 1997 to 2005, told EFE that thermo-valorization was a euphemism used to avoid calling the process by its real name: incineration.

Marisa Jacott, director of the non-governmental organization Fronteras Comunes (Common Borders), echoed that sentiment.

"Mexico signed the Stockholm Convention (on Persistent Organic Pollutants, which entered into force in 2004) to bring an end to incineration. So it can't accept technologies that generate highly toxic, persistent and bio-accumulative substances like dioxins and furans because there's no way to contain them," she said.

But Veolia, which operates 63 of these "waste-to-energy" plants worldwide, said in a statement that thermo-valorization was a process that generated low emissions of carbon dioxide and that the gases emitted into the atmosphere via the combustion of residues are treated in various stages using state-of-the-art technology to avoid the emission of dioxins.

"Veolia's operation guarantees that this installation will operate in complete conformity to the Mexican and European legislation for which it has been designed," the company said.