MARCH 4, 2009 32ND ANNUAL AIRPORT CONFERENCE

HERSHEY, PA

Innovative Approaches for Managing Stormwater Runoff:

Constructed Wetlands

KIM MINKEL, NFTA

Project Background

Buffalo Niagara International Airport

110 daily flights, 25 gates96” Avg. snow fall ~330,000 gallons glycol1.2 MGD stormwater

runoff

Deicing operations and practices

Deicing at the gates. Storm sewer design. Parallel system routes storm and glycol water. Glycol storage before discharging to a POTW. Glycol capture by GRV’s 45-48%.

Environmental Concerns

1994 - SPDES permit 30 mg/L BOD5 and 500 mg/L

glycol limit Frequent permit exceeded

1995 - Vacuum sweeping 3/1998 - The Citizen

Alliance Group targets NYSDEC

4/1998 NYSDEC issues Order on Consent - Comply by 2/99

Over the next 4 years…

~$13.1 million spent deicing controls, storage and treatment

Permit limits still exceeded

Neighbor complaintsTown prohibits

discharge

Concerns

Point source limit applying to a non-point source operation – Permit modification

It’s not working –treat everything or reduce use?

Large volumes – how do you treat this cost effectively?

How do you pay for this?

Action Items

Open SPDES permit 2004 – Generic RFP issuedPetition for funding

Modify permit – stream impactTreatment Alternatives (non-point source) Eliminate (reduce) glycol

Alternatives considered

Dedicated sewer line to POTWAnaerobic/aerobic onsite

treatmentMembrane bioreactorsRecyclingInfratek systemsReed bed subsurface wetlandCentralized deicing recycling

Subsurface engineered wetland

Advantage – Lowest 20 year combined

capital and operating cost Effective treatment for

stormwater Totally Green process

Disadvantage – Space constraints Public acceptance (Will it work?)

Go for it!

2005 - RFP for a Treatability Study and Conceptual design

2006 - Awarded to Jacques Whitford/NAWE/Urban

Treatability study showing >95% reduction in BOD

2007- Design phase completed

GARRET A. MEAL, P.E., URBAN ENGINEERING

Stormwater ManagementImpacts

URBAN ENGINEERS

Buffalo Engineering firm with 10 offices 475 staff along the East Coast

Extensive airport and civil transportation experience

NY and local environmental permitting experience

Existing Infrastructure

Storm SystemStorm System Extensive Storm NetworkExtensive Storm Network Stormwater Vault (3+ MG)Stormwater Vault (3+ MG) OutfallOutfall

Glycol ContainmentGlycol Containment Major pipesMajor pipes Glycol storage tanksGlycol storage tanks Snow melt padSnow melt pad Sanitary sewer pump stationSanitary sewer pump station

Objectives

Treat Glycol ConcentrateTreat Glycol Concentrate Treat Glycol Contaminated StormTreat Glycol Contaminated Storm Maintain Runoff ControlMaintain Runoff Control Reduce or Control Deicing costsReduce or Control Deicing costs

What needs to be treated?

Concentrate – 100% Simple Common Pumped Discharge to sanitary Replace pumps, discharge to WTS

What needs to be treated?

Storm Would require 15 Million Gallons storage for 10

yr storm 25 Million Gallons for 100 yr storm

First Flush

Stormwater Management

Existing Design – Detention Design Storm Proposed Design for WTS Influent

Design Storm

First Flush Collection

Stormwater Management Strategies

Divert upstream areas directly to wetlands, where possible

Utilize wetlands for storm detention Utilize glycol infrastructure year round Design additional pumping capacity Evaluate emergency overflows Surface storage of severe storms

Conclusions

Storm Water Management Plan Know what you are handling

How will you capture and hold water for treatment

Evaluate Resources – Can primary use be modified

SCOTT WALLACE, JW NAWE

Glycol Treatment

Treatment Objectives

Provide treatment of contained deicing fluidDesign system for integration into airfieldIntegrate system into existing stormwater

management

Why Wetlands?

Subsurface flow constructed wetlands do not pose a bird-aircraft strike hazard (BASH)

More stable than mechanical treatment systems

Biggest challenge is oxygen transfer into subsurface flow beds!

Engineered Wetlands

Designed for Treatment

Drain LineAir Line

Mulch Layer Influent Line

Subsurface Bed Cross Section

Water Level

Glycol Treatment

Glycols are readily degradable by bacteria

Managing Peak Events

BNIA required peak shaving volume

assuming max. treatment of 10,000 BOD5 lb/day December 2002 - January 2007

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

9,000,000

10,000,000

12/1

3/02

2/13

/03

4/13

/03

6/13

/03

8/13

/03

10/1

3/03

12/1

3/03

2/13

/04

4/13

/04

6/13

/04

8/13

/04

10/1

3/04

12/1

3/04

2/13

/05

4/13

/05

6/13

/05

8/13

/05

10/1

3/05

12/1

3/05

2/13

/06

4/13

/06

6/13

/06

8/13

/06

10/1

3/06

12/1

3/06

Date

Co

nce

ntr

ate

in s

tora

ge

(gal

)

0

10,000

20,000

30,000

40,000

50,000

60,000

Dai

ly B

OD

5 lo

adin

g fr

om

colle

ctio

n s

yste

m (l

b/d

ay)

Concentrate in storage

Daily concentrate BOD5loading from collectionsystem large peak events

Process Sizing and Layout

Cells are designed for a total load of 10,000 pounds of oxygen demand per day

The equivalent to 50,000 people

Construction

Conclusions

System operation scales to glycol usageIn this case, the design had to handle variable

flows and concentrations from at gate deicing The design provides flexible operations

Winter = glycol treatment Summer = storm storage

Lessons Learned

Communicate early and oftenNever forget your key missionEvery airport is differentDesign with flexibility in mindListen to your stormwater engineer