Sustainable water management with multi-quality recycled water production: the example of San Luis Potosi in Mexico

This paper presents and discusses the performance, reliability of operation, socio-economic and environmental aspects and benefits of the Tenorio Project in San Luis Potosi. This is the first project in Mexico making possible the production of multi-quality recycled water for planned water reuse for different purposes, including industrial cooling in a power plant, agricultural irrigation, groundwater restoration and environmental enhancement. Long-term water quality monitoring demonstrated the reliability of operation of the selected treatment trains, which were well adapted to local conditions and the given reuse application. The major challenge was the control of the conductivity and silica content in recycled water for industrial reuse, which needed complementary investigations and the implementation of an additional treatment by ion exchange. The reliable operation of the power plant with recycled water encouraged other industries to explore water reuse as an option, as well as the possibility of improved treatment. Once the main technical and social challenges of the original project were overcome, the project acquired a new dimension with the request of the industrial client to improve water quality by means of reverse osmosis. In return, the power plant proposed giving their right for water withdrawal from the aquifer to the City of San Luis Potosi, allowing thus the availability of freshwater for augmentation of the potable water supply.