The Fideicomiso del Sistema de Aguas Residuales del Alto Río Blanco (FIRIOB) in Mexico awarded a design-build-operate contract to the US company Earth Tech of Long Beach, California for a wastewater treatment plant in the city of Orizaba, located 200 km southeast of Mexico City.
The 20-year, US$ 15.45m DBO project, is one of the largest anaerobic/aerobic wastewater treatment systems in the world. When finished, the system will treat 28.5 million gallons of wastewater per day with a biochemical oxygen demand of 109.9 tons per day. The facility will treat wastewater from Orizaba in addition to wastewater produced from a paper mill, brewery facility and 12 other industries. Work on this project is scheduled for completion in August 2004.
The wastewater treatment system will include coarse screening, sand trap, fine screening, equalisation, anaerobic and polishing aerobic step with nitrification and denitrification. For solid wastes, the facility includes sludge storage tank, rotary thickening, centrifuges and rotary kiln incinerator. The fuel for this incinerator will be the biogas generated in the anaerobic reactors.
FIRIOB, which translates to the Trust of the Residual Water System of the High Blanco River, is a private industry joint venture that will finance 70% of the project. The remaining 30% of the project will be financed through the local government.
