2001 Water — Co-winner 2
Quebec Urban Community, Quebec
Using dynamic management and sophisticated forecasting to control wastewater flows
The Quebec Urban Community (QUC) has developed the world's first dynamic real-time water management system, including a srainfall prediction system. The system prevents pollution by limiting the overflow of wastewater into watercourses when it rains. In 2000, the region completed a two-year pilot project at Jacques Cartier Beach confirming that the system can reduce wastewater overflow frequency by almost 60 per cent and volume by 50 per cent. The pilot project cleared the way for the QUC to implement its full-scale overflow control project.
The QUC receives considerable precipitation between May and September: 458 millimetres on average. Before it embarked on a water management pilot project, these heavy rains caused untreated wastewater to overflow about 50 times a summer (about once every two to three days) with a total overflow of almost 5.6 million cubic metres. About one third flowed out of the region's western network of sewers, making swimming at neighbouring Jacques Cartier Beach impossible at times. Overflow events were magnified by tides, which often trapped wastewater at the beach for more than 48 hours.
In an attempt to keep pace with its wastewater processing needs, the region built two new purification plants, both operational in 1992. The plants, each costing $350 million, met the region's needs during dry spells. However, the wet summer months still posed a significant problem.
- QUC tested the system for the first time in the summer of 1999. Dynamic management reduced the volume of overflow by 78 per cent at Jacques Cartier Beach. Frequency of overflow was reduced by 28 per cent because only two rainfalls were fully controlled by the system. The region expects to improve upon that performance. The results were also attributable to the physical limitation of the control site: with only two holding tunnels in place, no more wastewater flow could be intercepted.
- For the summer of 2000, the first full season of operation, preliminary results show a 42 per cent reduction in overflow frequency. Results also show a 75 per cent reduction in overflow volume, representing more than 138,000 cubic metres of wastewater.
- Based on the pilot project results, QUC believes that under a full-scale project the system could reduce the frequency of wastewater overflow by almost 60 per cent and reduce the volume of overflows by at least 50 per cent.
- For the first time since monitoring began in 1992, water quality tests at Jacques Cartier Beach during summer 2000 showed that the beach was not polluted.
- Planners estimate that project costs would have been double without dynamic management and a sophisticated rainfall forecasting system. And, without the system's fine-tuning, the region would have needed twice the holding tank capacity.
- The QUC won a gold medal at the 2000 Distinction Awards gala in Hull, Que. The Federal Government presented the award to QUC as part of Technology in Government Week.
- The United States Environmental Protection Agency (EPA) has been interested in BPR's concept since 1996. In 2000, the region agreed to allow performance testing of wastewater flow under the EPA's Environmental Technology Verification Program.
- The pilot project demonstrates that the concept could be used in other medium- and large-sized municipalities. The results have convinced Paris, France, to install a dynamic management system over the next few years. Furthermore, BPR, which developed unique technical expertise over the course of the project, conducted several studies over the summer of 2001 on the feasibility of implementing dynamic management in several U.S. cities. Many American wastewater experts have travelled to Quebec City to view the control facilities.
- The project was very complex. It was important to schedule occasional pauses in the system's construction to test and alter the implementation process when necessary.
- To obtain the best results, the wastewater in the holding tunnels must be transferred to the region's wastewater treatment facilities at the correct rate. Detailed adjustments to the dynamic management system are essential in attaining optimum performance.