Joletta Golik
Lambert – St. Louis International Airport
Dean Mericas
CH2M HILL
May 23, 2012
Overview
 Background on Lambert
 Permit history
 Deicing runoff management system
 Permit renewal process and planning
 DNR response to demonstration of flaws in existing and proposed permit
 Lessons learned
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d
Lambert‐St
Louis International
Lambert
St. Louis International Airport: Profile
 30th busiest airport in the U.S.
 11 Airlines
 253 daily departures
 13 million passengers annually
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y
 4,000 acres of land
 180 tenants with diverse practices associated p
with the stormwater permit 3
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Permit History
 Original 1992 individual permit
 BOD5 = 45 mg/L max / 30 mg/L avg
 COD = 360 mg/L max / 180 mg/L avg
 Renewals
 2001: Same limits
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li it
 2006: Administrative extension
 2008 Initial pre‐publication draft proposed reduced COD limits
BOD5 = 45 mg/L max / 30 mg/L avg
COD = 120 mg/L max / 90 mg/L avg
Deicing Runoff Controls to Comply with
Deicing Runoff Controls to Comply with Permit Limits
 Practices
 Urea ban
 Aircraft deicing in designated areas
 Collection system
 Junction chambers on primary trunk sewers
J
ti h b i
t
k  Force main to 1.7 MG storage tank
 Collected run‐off discharged to sanitary sewer
 System switched between “in collection” (to tank) or “out of collection”
 Periodic review and enhancements
Performance of Deicing Runoff Controls
Performance of Deicing Runoff Controls Exceeds Proposed 2009 ELG
Deicing Season
D
i i S
2009 – 2010
2010 2011
2010 –
2011 – 2012 (provisional))
(p
Glycol Applied ( l PG)
(gals PG)
136,000
174 000
174,000
Glycol Captured
Gl
l C
d
25%
27%
70,000
22%
Outfall 006 COD Observations
1400
CO
OD (mg/L)
1200
1000
360 mg/L
800
600
400
200
120 mg/L
(proposed) 0
Conclusions after review of 2008 Conclusions
after review of 2008
Proposed Draft Permit

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System (mostly) working as designed
No evidence of downstream water quality problems
Screening level analysis suggests permit limits are not appropriate
Monitoring and limits at intermediate outfalls serve no useful purpose
Permit renewal presents opportunity to reevaluate limits and management plans
Permit Renewal Planning
Enhance collection system and practices
2. Identify basis of existing BOD and COD limits
3. Address Anti‐backsliding / Anti‐degradation constraints
4. Conduct water quality study to establish science‐
C d li d bli h i
based limits
1.
1 Enhance collection system and
1. Enhance collection system and practices
Conducted Deicing System Investigation:
 Monitor three winter storms (2009 – 2010)
 Investigate junction chambers, internal outfalls, surface flow, and Terminal 2 system
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y
 Three to six times per day:  Water samples for analysis, COD and some BOD
 Measurement of flow rates
 Compile ADF usage information (provided by airlines)
 Evaluate collection performance
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Deicing System Investigation‐
Deicing System Investigation‐
Conclusions
 Overall, collection system worked well
 Two junction chambers were improved
 Overall capture about 25% ‐‐ exceeding proposed USEPA ELGs
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2 Identify basis of existing BOD and
2. Identify basis of existing BOD and COD limits
 FOIA review of DNR files
 BOD limits based on secondary WWTP standards
 WWTP discharges are fundamentally dissimilar to deicing stormwater discharges
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 COD limits based on “best professional judgment and 40 CFR Part 419 Petroleum Refining.”
 No documentation
 No water quality basis
3 Address Anti backsliding and Anti
3. Address Anti‐backsliding and Anti‐
degradation
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“… statutory provision that prohibits the renewal, reissuance, or modification of an existing NPDES i
difi ti f i ti NPDES permit that contains effluent limits, permit conditions or standards that are less stringent than conditions, or standards that are less stringent than those in the previous permit.” ‐ TnDEC NPDES
Anti‐backsliding
exceptions
Anti
backsliding exceptions depend on basis of limits
Tech
Based
WQ Based
New information that was not available at the time of permit issuance
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Technical mistakes or misinterpretations of the law in permit issuance
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Events beyond the permittee’s control and no reasonable available remedy
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Exceptions Allowed
Substantial alterations or additions to permitted facility
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y
Permit modified under 40 CFR §122.62, or variance granted
Permittee unable to meet the permit limitations after properly operating and maintaining required treatment facilities
A ti b k lidi
lifi ti
Anti‐backsliding qualification
Regardless of any exceptions met, backsliding is Regardless of any exceptions met
backsliding is prohibited if the less stringent limitation:
 Violates applicable effluent limitations guidelines (ELGs)
 Violates water quality standards, including anti‐
Violates water quality standards, including anti
degradation
4 E bli h B i f Al
i
4. Establish Basis for Alternative Limits
 Two options:
1. Technology‐based limits (ELG)
T h l
b d li it (ELG)
2. Water quality based limits (WQBELs)
 Adopt whichever is most stringent
Water Quality Study Overview
 Three winter storms (2009‐2010)
 Monitoring at eight stream locations
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 Three times per day:
 BOD, COD, glycols, & acetate
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,
 Field parameters: Temp., dissolved oxygen (DO)
 Flow
 WQBEL analysis using QUAL‐2K model
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WQBEL
i
d i QUAL 2K
WQBELs estimated using QUAL‐2K stream model
stream model
Water Quality Study‐Results
 DO consistently well above 5.0 mg/L
 Existing limits much lower than needed to protect the creek
k
 BOD5: 45 mg/L in permit versus ~2,000 mg/L WQBEL
 COD: 360 mg/L in permit versus ~4,000 mg/L WQBEL
COD: 360 mg/L in permit versus 4 000 mg/L WQBEL
 Most BOD & COD is from pavement deicers, not aircraft deicers
 Options to control pavement deicers are limited
 EPA: “No available, economically achievable means for controlling…” (74 Fed. Reg. 44691)
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DNR Response to Information
DNR Response to Information Submittal
 Agreed to removal of intermediate outfalls from the permit
 Proposed replacement of effluent limits with facility‐
specific seasonal benchmark values
“Technology‐based limits with a water quality backstop”
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Benchmarks as described in the
Benchmarks as described in the 2012 Proposed Lambert Permit
 Benchmarks are not:
 Direct numeric effluent limitations
 Best Available Technology (BAT) or Best Control Technology (BCT) level performance
 A permit violation if exceeded
 Benchmarks are for:
 Determining the overall effectiveness of Lambert’s program
 Identifying when additional corrective action may be necessary
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Calculation of Facility‐specific
Calculation of Facility‐specific Benchmarks
 Based on past 5 years of Discharge Monitoring Reports
 Two seasons defined
 Deicing season:
November ‐ April
 Non‐deicing season: May – October
 Daily maximum COD benchmark calculated as:
 95th percentile value
 Long‐term “average” COD benchmark calculated as:
 95th percentile 5‐year median value
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Lessons Learned
 Examine the basis for permit requirements as the first step 



in addressing non‐compliance problems
 If you don’t understand the problem, you’ll come up with the wrong solution
’ll i h h l i
 Permits written for unusual operations may be based on inappropriate templates/assumptions
Anti‐backsliding is not an impenetrable obstacle but must be addressed
Water quality standards must be maintained
Collaboration with permit writers can lead to innovative solutions
Assume nothing
Questions?