Document 1564644

ENVIRONMENTAL FACT SHEET
ROUGE RIVER OUTFALL DISINFECTION PROJECT
Stormwater, Asset Management, and Wastewater Program Loan Project No. 2002-01
September 2015
Applicant:
Authorized
Representative (Interim):
City of Detroit Water and Sewerage Department
Water Board Building, Fifth Floor
735 Randolph Street
Detroit, Michigan 48226
Ms. Sue McCormick, Director
PROJECT OVERVIEW
The Detroit Water and Sewerage Department (DWSD) seeks a low-interest loan up to
$10 million through the Michigan Stormwater, Asset Management, and Wastewater (SAW)
program to finance the engineering study, design, and a portion of construction of the Rouge
River Outfall (RRO) disinfection project at the Wastewater Treatment Plant (WWTP). The
project is necessary to enable DWSD to meet a state regulatory requirement to disinfect all
discharges of treated effluent from the plant, which is located in southwest Detroit near the
confluence of the Rouge River and Detroit River.
Construction and non-construction activities are expected to cost up to $40 million between
2014 (engineering study) and 2019 (completion of construction). Project costs beyond the
$10 million SAW limit may be financed by a combination of remaining balances from current and
future revenue bond proceeds and transfers of operating revenue. During the construction
phase, the project may seek additional low-interest loan funding through the Michigan State
Revolving Fund (SRF) program. To preserve future SRF eligibility, the DWSD is following
contract procurement steps that meet new federal requirements.
BACKGROUND
The DWSD wastewater system collects and treats wastewater generated within the city of
Detroit and 76 suburban communities in Wayne, Macomb, and Oakland Counties. The DWSD
system currently serves more than 2.8 million people in more than 1.1 million households.
The DWSD’s program to control combined sewer overflows (CSO) recommends the use of
in-system storage capacity and construction of CSO treatment facilities at CSO outfalls to
control overflows to the Detroit and Rouge Rivers. However, the first priority is transporting
wet-weather flows to the WWTP for treatment, and optimizing all available treatment capacity.
The plant has the capability of handling wet-weather flows up to 1,700 million gallons per day
(MGD). The plant maximizes the use of the Detroit River Outfall (DRO) to ensure that treated
wastewater is disinfected (chlorinated) and dechlorinated prior to discharge to the Detroit River.
The DRO capacity is approximately 1,100 MGD.
During wet weather when influent flow to the WWTP exceeds its secondary treatment capacity,
the excess flow receives only primary treatment. Both the secondary treated effluent and
primary treated effluent are disinfected and dechlorinated before being discharged through the
DRO (No. 049F). When peak flow exceeds the DRO hydraulic capacity, the WWTP discharges
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excess primary treated effluent through the Rouge River outfall, or No. 050; however, flows
through the RRO receive no disinfection and no dechlorination.
On average, there are 20 to 40 wet-weather events per year when excess primary effluent is
discharged through the RRO. These discharges average 12 billion gallons annually. The
discharge of undisinfected wastewater into the Rouge River poses a public health risk for
boaters, swimmers, and fishers.
To protect the public health, the Michigan Department of Environmental Quality (DEQ) originally
required DWSD to achieve disinfection of all wet-weather treated discharges from the WWTP by
July 1, 1997. However, over the next ten years, two major construction projects were
discontinued and failed to achieve the ultimate goal.
In early 2010, the basis of design was completed for another disinfection alternative that would
have involved construction of a new open-box surface conduit to the Rouge River, a new outfall
discharge structure in the river itself (known as RRO-2), a new junction chamber, and new
chlorination and dechlorination facilities. In November 2011, in anticipation of SRF funding, the
DEQ published a detailed environmental assessment for the proposed RRO-2 project. The
DEQ determined that the RRO-2 project would not cause significant adverse impacts to the
Rouge River or its floodplain; animal or plant species; historical properties; archaeological sites;
or local communities near the WWTP.
On December 2, 2013, the DWSD submitted Part A of the SAW loan application to the DEQ,
requesting a SAW loan to cover engineering study and design costs for the RRO-2 conduit and
outfall project. Because the application met all SAW requirements, and estimated project costs
exceeded $90 million, the DEQ reserved the maximum allowable $10 million for a SAW loan.
In 2014, additional engineering studies at the WWTP revealed that a significantly less expensive
alternative could use existing conduits and the existing RRO, thereby obviating the need to
construct a new RRO-2. Three revised alternatives were examined, and the most cost-effective
one was chosen. The selected alternative also involved the least complicated operating
scheme. On October 21, 2014, the DEQ Water Resources Division approved the technical
conceptual basis for the selected alternative.
Although the DWSD originally sought SAW funding assistance for the engineering study and
design phases of the RRO-2 project, it now seeks assistance for the engineering study, design,
and a portion of construction of the less expensive RRO project, which is the focus of this
environmental fact sheet. Compared to the prior RRO-2, the RRO is expected to save tens of
millions of dollars in study, design, and construction costs.
PROJECT NEED AND ELIGIBILITY
The RRO disinfection project is needed to comply with DWSD’s National Pollutant Discharge
Elimination System (NPDES) permit MI0022802 issued March 1, 2013. On June 22, 2015, the
DEQ issued a permit modification. Among other revisions, the modification removed the RRO-2
project and replaced it with the RRO project. It also accounted for the different flow routing
during wet-weather events.
Disinfection of all wet-weather flows through the RRO is environmentally critical for public health
protection. Moreover, completion of the project has important ramifications for Detroit’s CSO
control program: the adaptive management program requirement is predicated on completion of
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the RRO project. Additionally, the Administrative Consent Order ACO-000131 of July 8, 2011,
as amended May 18, 2012 (AACO-000020), requires a preventive maintenance plan that
includes some of the elements of an Asset Management Program (AMP). Moreover,
the NPDES permit requires DWSD to prepare, submit for DEQ approval, and progressively
implement an AMP. To meet its NPDES permit date, the DWSD submitted its AMP document
to the DEQ on December 30, 2013, and the DEQ approved it with conditions on January 17,
2014. The DWSD is proceeding with a phased implementation of the AMP.
The DEQ-approved AMP includes a capital planning process that yields an annual capital
improvement program report. This report has included the RRO project since 2012, when it
originally was conceived as the RRO-2 project. Inclusion of the RRO project in DWSD’s
wastewater AMP makes it eligible for a SAW loan under Part 52, Section 324.5202(1)(d) and
Part 53, Section 324.5301(d) of 1994 Public Act 451, as amended.
On November 26, 2014, the city of Detroit and the counties of Wayne, Macomb, and Oakland
formally approved the formation of the Great Lakes Water Authority (GLWA). At the time of this
environmental fact sheet (September 2015), detailed processes are underway to shift wholesale
water and sewerage services for suburban customers to the GLWA, and retail services for city
customers to the DWSD. Because the transition is not yet finalized, this fact sheet focuses on
the SAW project proposal submitted by the DWSD on December 2, 2013, and updated on
August 12, 2015.
Even if the DWSD remains the SAW loan applicant, updated application materials and an
updated SAW resolution will be required prior to loan closing. Moreover, if the GLWA should
become the successor applicant for the SAW loan, then the legal and financial details must be
addressed to achieve the transition. If either the DWSD or the GLWA should seek
supplemental low-interest loan funding in fiscal year 2017 through the SRF program, an
updated SRF project plan will be required by July 1, 2016. Other SRF requirements will also
need to be met for a potential future SRF loan.
RRO DISINFECTION PROJECT
Most of the proposed work for the RRO disinfection project will be on the WWTP property. The
project will utilize the existing chlorine contact conduits and the RRO to transport secondary
effluent and excess primary effluent whenever the DRO capacity is exceeded. To achieve
proper chlorination and dechlorination, and to modulate treated flows between outfalls,
significant modifications are required at the WWTP. In addition to modifications to existing
conduits, the work will include new rapid-mix chlorination facilities for primary and secondary
effluent; a new dechlorination facility at the downstream end of the RRO; various pipelines, port
holes, drop pipes, and flow-control structures; flow meters; and instrumentation and control
systems.
When completed, the proposed RRO disinfection project will result in secondary treated effluent
flow and excess primary treated effluent flow during wet-weather events being discharged
through the DRO, up to the hydraulic capacity of the DRO. This currently is how the DRO
operates, and all flows conveyed through the DRO will continue to be disinfected prior to
discharge. Once the DRO capacity is reached, the future flow routing scheme will partition
treated effluent as follows. As the total WWTP flow increases above the hydraulic capacity of
the DRO, a portion of the secondary flow (an amount equal to the increase in WWTP flow above
the DRO hydraulic capacity) will be disinfected, dechlorinated, and discharged through the
RRO. The remainder of the secondary flow and all primary treated flow will be disinfected and
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discharged through the DRO. Currently, once the DRO capacity is reached, all excess primary
flow is discharged without disinfection through the RRO.
IMPACTS AND BENEFITS
The proposed RRO disinfection project will be constructed on DWSD-owned property at the
WWTP located along West Jefferson Avenue in southwest Detroit. The area of proposed
construction has been heavily developed for more than 100 years to accommodate various
industrial, commercial, and wastewater treatment purposes.
Design of the RRO disinfection project will occur in several phases beginning in late 2015. To
meet the NPDES permit schedule of implementation, the DWSD intends to utilize a progressive
design-build contract. The DEQ will review and approve the phased design submittals under
the Part 41 authority of 1994 Public Act 451, as amended. According to the permit schedule,
the first design deliverables are due June 1, 2016, and final design of at least the first
construction phase is due by November 1, 2016. Construction is required to commence by
April 1, 2017.
Before construction can proceed, the contractor must obtain all required permits, which likely
will entail a construction site stormwater discharge permit from the DEQ; a soil erosion and
sedimentation permit from the DWSD; a building permit from the city of Detroit; a permit from
the Wayne County Department of Public Services for temporary disruptions of Jefferson Avenue
(associated with modifications to the chlorine contact conduits); and a DEQ permit for
construction in the Rouge River and its floodplain. The DWSD will contact the U.S. Army Corps
of Engineers to ensure the project meets jurisdictional requirements regarding navigable rivers.
Construction activities will generate construction traffic, dust, and diesel fumes in the immediate
area of work, but these minor, localized, temporary impacts will be controlled by standard
mitigation measures. Construction will cause only minimal traffic disruptions because most
work will be accomplished on the WWTP property. Work involving the chlorine contact conduits
at Jefferson Avenue will be achieved in a manner that maintains traffic in both directions. If
contaminated soils or groundwater are encountered during construction, technical specifications
in the contract documents will address the proper removal, handling, and disposal of these
materials.
The NPDES permit requires construction to be complete by April 1, 2019. At that time, the
DWSD expects to be able to completely disinfect and dechlorinate all treated wastewater
effluent prior to discharge from the WWTP via the DRO and RRO. Therefore, the major
environmental benefit will be improved water quality in the two receiving waters – the Detroit
River and the Rouge River. Disinfection via chlorination will destroy microorganisms that could
threaten human health, and dechlorination will ensure that potentially toxic residual chlorine
levels in the effluent are controlled to meet water quality standards and protect aquatic biota in
the rivers.
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