Nogales International Wastewater Treatment Plant Rehabilitation Project, Arizona, USA
Key Data:
Population served
350,000 (Mexico); 22,000 (US)
Annual inflow
US
16,300m³/day
Mexico
38,600m³/day
Final capacity
53,000m³/day
New secondary treatment system
Modified Ludzack-Ettinger
Effluent criteria
BOD5 (average)
20mg/l (monthly); 30mg/l (weekly)
TSS (average)
20mg/l (monthly); 30mg/l (weekly)
Filtered effluent turbidity
10 NTU (24-hour average)
Total nitrogen
10 mg/l (5 month rolling geometric mean)
Faecal coliform
2.2 CFU (seven sample median); 23 CFU, (single sample maximum)
Residual chlorine
5ug/l (monthly); 11ug/l (daily)
Total project cost
$60m
Project Timeline:
Clean Water Act violations law suit filed
March 2000
Court-ratified agreement
2001
Initial compliance deadline
January 2004
Evaluation of alternatives completed
September 2005
Grant agreement signed
December 2005
Construction management tender closed
March 2006
Construction management contract awarded
September 2006
Scheduled completion
October 2009
Key Players:
Plant co-owners/operators
City of Nogales and the International Boundary and Water Commission
Technology evaluation
Camp Dresser and McKee
Design review/Construction management
Atkins and Faithful & Gould
Funding
North American Development Bank Grant and the US Environmental Protection Agency (EPA)
Working group members
US International Boundary Water Commission and Arizona Department of Environmental Quality, the EPA, the Border Environment Cooperation Commission, the University of Arizona, the North American Development Bank and the City of Nogales.
