Chicago, renowned for its architectural marvels and bustling city life, is also home to two of the world’s largest water treatment plants, the James W. Jardine Water Purification Plant and South Water Filtration Plant. These colossal structures, situated along Lake Michigan’s shores, play a critical role in supplying clean water to millions of people in Chicago and surrounding areas.
Immense Scale and Unwavering Standards
The sheer magnitude of these plants is awe-inspiring. Last year alone, they collectively pumped a staggering 1,048 million gallons per day, meeting the needs of over 5 million residents across Chicago and approximately 118 neighboring communities. Such a monumental task requires adherence to stringent guidelines set by the United States Environmental Protection Agency and the Illinois Pollution Control Board.
Delving into the Intricacies
To comprehend the water treatment process, let’s dive into the details. Each facility employs intake cribs located 2 to 2.5 miles off Lake Michigan’s shore. Water flows from these cribs through large intake shafts and travels through screens designed to filter out fish, weeds, and other larger particles. Subsequently, “Low Lift” pumps raise the water approximately 20 feet, allowing gravity to take over for the remainder of the process.
The treatment process involves the use of various chemicals such as chlorine, alum, polymer, blended phosphates, carbon, and fluoride. These substances aid in disinfection, coagulation, corrosion prevention, lead leaching mitigation, and taste and odor control. After coagulation, the water moves into settling basins before passing through conventional sand and gravel filters and eventually reaching the reservoirs. An underground tunnel system effectively delivers water to pumping stations throughout Chicago, capable of supplying more than 2.5 billion gallons daily. Jardine and South Water, on average, pump 661 and 387 million gallons per day respectively.
Over the past few years, the water entering Lake Michigan has benefited from the presence of zebra mussels. These small snail-like creatures act as natural filters, cleansing up to a liter of water each day. Their presence has significantly contributed to the water’s cleanliness.
Unwavering Commitment to Monitoring and Data Acquisition
With great responsibility comes meticulous planning and monitoring. The Jardine facility maintains 92 chemical tanks, and the South Water plant boasts 56. These tanks, including receiving, storage, and day tanks, undergo continuous monitoring at the Chemical Application Control Center in South Water and the Transfer Center in Jardine.
The original float gauging system for tank data acquisition has been upgraded to a state-of-the-art system, enhancing accuracy. Today, the Jardine facility employs L&J Engineering’s MCG 2000 transmitters, coupled with conventional tape and float gauges, providing precision to an accuracy of almost one-eighth of an inch. Redundant systems automatically alert operators when preset levels are reached.
The South Water Facility utilizes a similar data acquisition system. Flow ranges depend on the specific chemical demand. For instance, alum, used in the coagulation process, is fed at a rate of 20 to 100 lbs. per million gallons, depending on water quality. Carbon, employed for taste and odor control, can be set to flow between 0 and 4.5 gallons per minute or up to 0 and 40 gpm, with the chemical being fed into 10 different feeders during the process. Both facilities uphold high standards of flow monitoring.
Fluoride and carbon tanks employ advanced ultrasonic-type gauging systems connected to L&J Engineering’s 1200SS transmitter. Analog signals are converted to digital data, displayed, and transmitted via the L&J 4-wire digital highway to the system computer. The Chemical Applications Control Center/Transfer Center continuously monitors this data. Throughout the system, L&J Engineering’s 3600 mini computer/receiver system, an embedded microprocessor, captures local information and sends it to the host. At the core of the setup lies the MCG 3400 (DOS based), which collects data from six satellite clusters of 3600s consistently acquiring data.
The Future of Water Treatment
Both facilities are poised to upgrade their current systems with L&J Engineering’s MCG 3900 Inventory Management System. This advanced system, designed to operate in the Windows 95/98 or NT environment, offers tank gauging and inventory management capabilities. It seamlessly interfaces with various PLCs, including the Allen Bradley system presently in use.
The forthcoming upgrades serve several purposes. First, they ensure Year 2000 compliance. Second, they transition from a DOS-based system to a more user-friendly interface. Third, they provide plant-wide data. Fourth, they enable remote gauging. Lastly, they facilitate seamless integration with the SCADA systems at each facility.
Unlike the Jardine facility, the South Water plant boasts ample room for expansion as needed. Both plants exceed the required standards to consistently deliver pure, safe drinking water to the City of Chicago. The existing process, proven to be highly efficient, requires no significant changes.
In conclusion, Chicago’s water treatment facilities stand as testaments to human ingenuity and technological prowess. They combine cutting-edge tools, diligent monitoring, and unwavering commitment to ensure the provision of clean water to millions of individuals. As the city continues to grow, these facilities will evolve and adapt to meet the demands of tomorrow, always prioritizing the well-being of the community.