In a joint project team with the client, Grontmij is responsible for process design, preliminary design, process control and automation systems, and assistance with start-up and operation. The plant will be operational in the second half of 2009.

The wastewater treatment plant Aïre 2 at Geneva is one of the three largest wastewater treatment plants in Switzerland. The capacity amounts to 600.000 population equivalents at a maximum hydraulic capacity of 18.000 m³/h. The plant discharges the treated wastewater of the city of Geneva into the river Rhône.

Standards for nitrogen removal
Currently the plant fails to meet standards for nitrogen removal during the winter period. Supplementary treatment capacity is necessary, also because of an expected increase in load in the near future. Services Industriels de Genève (SIG; the public utility of Geneva) has evaluated a number of specific nitrogen removal systems and has selected the SHARON technology of Grontmij as the best available technology. The construction of the SHARON system is part of an extension program for the total treatment plant.

Proven in an extensive selection
SIG has selected the SHARON process in an extensive system selection procedure, including a technological evaluation and additional site visits in the Netherlands and Austria. SHARON is selected for reasons of proven process stability, flexibility, robustness of operation and the competitive investment and operational costs.