Budget Message / Highlights - Metropolitan Water Reclamation ...

METROPOLITAN WATER RECLAMATION DISTRICT OF GREATER CHICAGO
2009 BUDGET
IEPA is to establish limits for fecal coliform bacteria in the final effluent at the Stickney, Calumet, and North Side
plants. This proposal is controversial, as it is based upon arbitrary limits, is not based on science, and is not supported
by the conclusions of the UAA conducted by the IEPA.
In order to provide the objective scientific conclusion that is lacking in the basis for IEPA’s proposed limits, the District
has conducted and commissioned numerous studies on this subject. These studies include “Spatial and Temporal
Characterization of Fecal Coliform in the CAWs,” “USEPA Bacterial Water Quality Review,” “Quantitative Microbial
Risk Assessment for CAWs Recreational Users,” “Epidemiological Study of Incidental Contact and Non-Contact
Recreation on the CAWs,” and “Chicago Area Waterways Recreational Study.” In addition, the District commissioned
a blue ribbon task force to determine the most appropriate technology for disinfection if it were to be implemented, and
the costs for such implementation. Due to the high cost of disinfection, the Engineering Department has undertaken an
economic and environmental impact study for meeting the proposed effluent limitations.
The three WRPs which currently do disinfect the effluent use a chemical process of chlorination to deactivate the
pathogens, followed by the addition of sodium bisulfite to reduce chlorine residual. Free chlorine has been shown to
produce chlorinated byproducts which may be harmful to aquatic life. Because of this, in 2008, the District began a pilot
study to evaluate different ultraviolet light (UV) disinfection technologies side-by-side at the Hanover Park WRP. UV
disinfection inactivates bacteria without the use of chemicals. The District is evaluating three different technologies.
Two of the technologies utilize low-pressure high-intensity lamps, with one controlling dosage based on transmittance
and the other based on lamp intensity. The third technology is a unique system utilizing microwave technology instead
of the traditional bulb. Initial evaluation of these technologies is expected to be completed in 2009. The District will use
the results of this study to design UV disinfection facilities for the Egan, Kirie, and Hanover Park WRPs, to replace the
current chlorination/dechlorination chemical disinfection process.
Tunnel and Reservoir Plan Accomplishments
TUNNEL AND RESERVOIR PLAN
March 2006 marked the completion of three decades
of tunnel construction as part of the Tunnel and
Reservoir Plan (TARP). The tunnel system, Phase I
of TARP, is designed to capture up to 2.4 billion
gallons of the first flush of sewage contaminated
stormwater from combined sewers that had
previously flowed into the area waterways. This is a
major portion of the combined sewer overflows
(CSOs) into local rivers.
This project has produced major improvements in
local river water quality, greatly increasing the value
of property bordering the rivers. Wildlife, particularly
birds and fish, are returning as the water quality
improves. Reduction in obvious water pollution has
promoted increased recreational use of these
waterways, which presents other problems. The
waterways are still potentially unsafe for human body
contact due to bacterial contamination, and due to a
lack of access locations.
Phase II of TARP continues with the design and
construction of the McCook and Thornton
Reservoirs. The TARP reservoirs will greatly
increase the volume available for capturing
contaminated combined sewer overflows that
previously would have discharged to the rivers. The
ultimate storage capacity of the TARP system in
2024 will be approximately 17.5 billion gallons.
As of July 2008, approximately 58.7 million tons of
rock (77 percent of the total excavation) has been
mined from Thornton Composite Reservoir by
contract with Hanson Material Service Corporation
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