Graña y Montero SA has submitted an unsolicited proposal to build and operate at least 10 sewage-treatment plants in the Lake Titicaca (Peru) region. 

Peru's private investment promotion agency Proinversion will now determine whether the project is of public interest to allow Graña to carry out the Feasibility studies.

If approved, Graña y Montero plans 6 months of studies before starting work on the plants. Proinversion would decide whether the project is directly awarded to Graña or there is a public tender process.

The contract agreement would have a period of 30 years. The project would involve the design, construction, financing, operation and maintenance of the 10 sewage-treatment plants with an investment value of US$155 million.

The plants would be located in: San Román- Juliaca, Puno, Azángaro, Ayaviri, Huancané, Moho, El Collao, Juli, Lampa and Yunguyo. Other locations are still to be determined.

The project aims to reduce pollution that is tainting waters in the world's highest navigable lake. Five major river systems feed into Lake Titicaca. In order of their relative flow volumes these are Ramis, Coata, Ilave, Huancané, and Suchez. More than twenty other smaller streams empty into Titicaca.

Titicaca is located at the northern end of the endorheic Altiplano basin high in the Andes on the border of Peru and Bolivia. By volume of water, it is the largest lake in South America. The lake, at 3,100 meters (12,500 feet) above sea level, is a popular tourist attraction that straddles the border between Peru and Bolivia. Population growth and the expansion of unregulated mining activity have increasingly contaminated the 8,300-square-kilometer (3,200-square-mile) lake.