Budget Message / Highlights - Metropolitan Water Reclamation ...

METROPOLITAN WATER RECLAMATION DISTRICT OF GREATER CHICAGO
2009 BUDGET
atmosphere. This process requires substantially more secondary treatment capacity and pumping capacity than a typical
secondary treatment process because the treatment requires increased recycle in the secondary process. The use of a
series of anoxic and aerobic zones can be effective to treat to total nitrogen in the range of 8 mg/L. Using a biological
filter and addition of a carbon source can further reduce total nitrogen to the range of 3 - 5 mg/L. For the combined
capacity of all the District plants, this process would be operationally very expensive, and cost on the order of several
billion dollars to install.
Wetlands
The District is investigating several potential wetland demonstration projects aimed at evaluating alternative methods
for dealing with nutrients. Anaerobic bacterial reduction of nitrates to nitrogen gas in wetlands is known in principle and
from some demonstration projects, but not at a scale or under specific conditions needed for District requirements.
Using wetlands for nutrient removal can be a market-based strategy that uses restored floodplain wetlands designed,
built and operated for the purpose of managing nutrients, trapping sediments, and/or storing floodwaters. These
wetlands would produce nutrient reduction credits that can be sold to municipal or industrial treatment facilities that
need to meet a water quality standard and cannot cost-effectively remove nutrients themselves.
Recent studies have suggested that wetland-based nutrient removal will reduce the cost impact on homeowners within
the MWRD service area by 51 percent in comparison to the implementation of conventional wastewater treatment
technology needed to meet eventual Illinois water quality standards.
Treatment Wetlands Study at Lockport
Powerhouse Marsh
Des Plaines
River
Chicago
Sanitary
and Ship
The District currently is designing two pilot treatment wetlands on
its property to demonstrate nutrient removal near the Lockport
Powerhouse and along the Centennial Trail north of 135th Street.
Data obtained from these wetlands under local conditions could be
applied to potentially larger operational wetlands.
The District is also investigating another project. In the Lake
Calumet area, the District is studying, in conjunction with the City of
Chicago, the feasibility of a concept to create wetlands and modify
existing wetlands to remove nutrients from Calumet WRP effluent.
Habitat protection and recreational opportunities would be integrated
into the project.
Wetlands can also have additional benefits of long-term sequestering
of carbon as peat, mitigating downstream flooding, providing
recreational areas, and recreating native habitat for many fish,
wildlife, and plant species. Many endangered species inhabit
wetlands or wetlands play an important part of their life cycle.
Wetlands contribute to the maintenance of biological diversity.
Wetlands can help improve water quality by removing or retaining
nutrients, organics, and sediment carried by runoff.
Contaminated Sediment Remediation
A one-acre contaminated sediment capping and wetland creation
demonstration project is being designed and will be constructed in
collaboration with the University of Illinois at Chicago and The
Wetlands Initiative, in the Collateral Channel on the Sanitary and
Ship Canal near Kedzie Avenue. This is a $5.3 million project in the
Corporate Fund. Success of this demonstration project will be critical
in dealing with contaminated sediments in other parts of the Chicago
Waterways System.
Water Quality Initiatives
On October 26, 2007, the Illinois Environmental Protection Agency (IEPA) initiated a rulemaking with the Illinois
Pollution Control Board, captioned “In the Matter of: Water Quality Standards and Effluent Limitations for the
Chicago Area Waterway System and Lower Des Plaines River, Proposed Amendments to 35 Ill. Adm. Code 301, 302,
303 and 304” (R08-9). The rulemaking arises out of a Use Attainability Analysis (UAA) conducted by the IEPA and
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