Water Online the Magazine gives Water & Wastewater Engineers and end-users a venue to find project solutions and source valuable product information. We aim to educate the engineering and operations community on important issues and trends.
Issue link: http://wateronline.epubxp.com/i/597858
CAWS without any adverse environmental impact. The treated water is often cleaner than the water of the rivers and streams. The entire process from the time water reaches the treatment plant to the time it is cleaned and reclaimed takes less than 12 hours. In addition to directly benefiting the water environ- ment, the disinfection project impacted the local economy by putting hundreds of tradespeople to work. Disinfection also clears the way for direct reuse of the water by industry. MWRD has entered into an agreement with Illinois American Water, and together they are pursuing the local industrial use of this disinfected water. Other environ- mental benefits of reusing water include saving the energy used to treat the water and conserving Chicago's tap water, which is sourced from Lake Michigan. "Disinfection marks another significant date in the his- tory of the Metropolitan Water Reclamation District of Greater Chicago, dating back to 1889, when the District was first tasked with addressing the issue of contamination in Lake Michigan," said MWRD President Mariyana Spyropoulos. "Since then, we have constructed more than 60 miles of canals, reversed the flow of the Chicago River, and built seven water reclamation plants. Creating a disinfection facility at Calumet is another chapter in our history of water treatment and one more upgrade we have made to improve the region's water quality." Two Forks Merge Chlorination/dechlorination is not the only resource recovery initiative the MWRD is pursuing. The MWRD is also con- structing a UV radiation system to disinfect water entering the CAWS at the O'Brien WRP. By using two distinct technologies, the MWRD will saturate the CAWS with disinfected water that enters the waterways from the south through Calumet WRP and the north at O'Brien WRP. The UV disinfection system will become the largest waste- water UV installation in the world. O'Brien WRP, which treats 530 MGD, will have 1,152 TrojanUV Solo Lamps installed. The TrojanUVSigna system uses 1,000-watt low-pressure high- output (LPHO) Solo Lamps. The low-pressure lamp means that fewer lamps are needed to accomplish disinfection versus medi- um-pressure (MP) lamps. Fewer lamps require less tank volume, which translates into a lower capital cost than MP lamps. The low wattage of operation translates into longer lamp life and lower power consumption. The total power requirement for the traditional MP UV lamps to disinfect a 530 MGD effluent flow at the O'Brien WRP is 5,068 kW versus 1,191 kW for the Solo Lamps. The significant difference in power means a lower annual operating cost for the MWRD system. The smaller number of lamps for the TrojanUVSigna system than the MP system also translates to reduced maintenance costs due to fewer lamps needing to be cleaned and replaced. The inclined configuration of the Signa system makes routine maintenance and lamp replacement quick and easy while the UV system is in operation. In addition, the facility will feature roof-mounted water source heat pumps that provide heating and air conditioning in the UV disinfection building and neighboring switchgear building. The heat in the treated water will be recovered to heat and cool the building, another resource-recovery initiative at MWRD. This system consumes roughly 25 percent of the energy of traditional HVAC systems. An energy-recovery ven- tilator is also being installed in a sampling room, control room, and washroom, and a rain garden is being created between the two buildings. Differences in existing infrastructure and hydraulics at the two plants required that a combination of methods be imple- mented. The task force also evaluated technologies that are best suited for both WRPs based on a triple-bottom-line approach that considered economic, environmental, and social criteria, while also providing quality customer service at the lowest cost. As a result, MWRD was able to do what was needed for less than half the cost of the original estimate. The MWRD restruc- tured its capital improvement program (CIP) and adjusted operational efficiency goals to reserve $240 million in the bud- get for construction based on early estimates; however, the task force was able to hold the line on expenses so that the estimated costs for capital did not exceed $109 million. Ultimately, the MWRD has allocated resources to allow disinfection to occur without tax increases. "The new Calumet disinfection facility will improve water quality for the growing number of people who kayak, water ski, and enjoy other recreational activities in the Chicago Area Waterway System," said U.S. EPA Region 5 Administrator Susan Hedman. "U.S. EPA is proud to have played a role in making this project happen — a project that created a lot of wateronline.com n Water Innovations DISINFECTION 9 The above images show the massive scale of the Thornton Reservoir.