Transcript Glycol Treatment at London`s Heathrow Airport

Glycol Treatment at London’s Heathrow Airport
Scott Wallace and Mark Liner – Naturally Wallace Consulting
David Cooper and Clodagh Murphy – ARM, Ltd.
Russell Knight – British Airport Authority
Aircraft Deicing
• Deicing fluids include ethylene glycol (EG),
propylene glycol (PG) and diethylene glycol
(DEG).
• Commonly used as a 50% concentrate form
(CBOD5 approximately 200,000 mg/L).
• Runoff can contain over 20,000 mg/L at 1 oC
• New environmental regulations are requiring
treatment of deicing runoff.
• Major challenge for conventional treatment plants
Deicing Runoff Treatment Options
• Anaerobic Digestion (biogas)
–Shock loadings, limited net biogas
• Mechanical Treatment (activated sludge, MBRs)
–Shock loadings, energy intensive
• Discharge to Regional Sewer
–Long-term concerns over cost and capacity
• Passive (ponds and open-water wetlands)
–Land intensive, BASH
• Subsurface Flow Treatment Wetlands
– No water exposed, land intensive
Original Heathrow Constructed Wetlands
• Papers published in 2001 and 2004
• 12 reed beds, total area 2.08 ha
• Design flow rate 40 L/s; influent COD of 170 mg/L
• Removal efficiency of 30-68%, 24-77 kg/ha-d
Richter et al. 2004
Overview of pollution control at Heathrow
Spout Lane Lagoon
Causeway Nature
Reserve – part of
Eastern Balancing
Reservoirs
Clockhouse
Lane Pit – Cable
1 part of Princes
ski club
Mayfield Farm main
reservoir
Total tons of BOD applied
The Case for Upgrading Mayfield Farm
400
1400
200
2010/11
2009/10
2007/08
2006/07
2005/06
2004/05
2003/04
2002/03
2008/09
Pavement
800
600
400
2010/11
2010/11
2009/10
2009/10
2008/09
2008/09
2007/08
2007/08
Winter
Period
Winter
Period
2006/07
2006/07
2005/06
2005/06
2004/05
2004/05
2003/04
2002/03
2003/04
2002/03
2001/02
2001/02
2000/01
0
2000/01
200
1997/98
0
Aircraft
1999/00
200
1000
Winter Period
1998/99
400
1200
1999/00
600
1400
1997/98
800
2001/02
1000
1998/99
1999/00
1998/99
1997/98
1200
BOD mass (tons) 2000/01
Total tons of BOD applied
0
BOD mass (tons)
BOD mas
600
Pavement
Aircraft Pavement
• Relatively mild winters post original construction Aircraft
(change
in design
basis)
• More stringent consent limits
Buffalo Niagara International Airport
• Heavy snow loads in winter
• Airfield operations are heavily dependent on
effective deicing operations
Treatability Testing
• Measure glycol degradation in both warm and
cold temperatures
• With and without aeration
Aerated rate coefficients, low
temperature runs
Run
Average CBOD5 (mg/L)
Effluent
Influent
k2TIS(d-1)
A
648.8
26.5
4.81
B
679.3
21.0
5.72
C
325.0
10.3
5.63
D
694.0
23.5
5.41
Average
5.39
PG degradation without aeration…
Run
Average CBOD5 (mg/L)
Effluent
Influent
k4TIS(d-1)
A
542.3
212.3
0.68
B
257.0
119.0
0.27
C
177.0
29.0
0.73
D
129.5
33.5
0.51
Average
0.55
Comparing Treatment Effectiveness
• Aerated rate coefficient:
5.30 d-1
• Non-aerated rate coefficient:
0.55 d-1
• An aerated wetland is 10X more effective in
treating glycol!
Buffalo – Completed Treatment System
Buffalo Airport Deicing Fluid Treatment 2010-2011
18,000
16,000
14,000
Influent CBOD5/TOC: 2.25
Effluent CBOD5/TOC: 0.45
Based on Stantec's Engineered
Wetland Treatment System BNIA
Calibration of TOC Meters Report
(6/4/2010)
Calculated CBOD5 (mg/L)
Influent
12,000
10,000
8,000
6,000
Effluent
4,000
2,000
0
10/29/2010 11/18/2010 12/8/2010 12/28/2010 1/17/2011
2/6/2011
2/26/2011
3/18/2011
4/7/2011
4/27/2011
Comparing Heathrow and Buffalo wetlands
Heathrow (prior to
upgrade)
Buffalo
Design COD load
590 kg/d
4540 kg/d
Area
2.08 ha
1.67 ha
Bed Volume
12480 m3
28370 m3
COD Loading
47 g/m3-d
160 g/m3-d
(clogging limited)
Aeration
None
750 kW
Oxygen Transfer
2.4 – 7.7 g/m2-d
270 g/m2-d
COD Removal
4 – 13 g/m3-d
Up to 160 g/m3-d
Flow Path
Horizontal
Vertical (due to high load)
Full- ScaleTrial
Winter 2009/10
Blower
..............
...............
...............
. .. . . . . . . . . . . . . .
...............
...............
...............
...............
...............
...............
..
..............
...............
...............
. .. . . . . . . . . . . . . .
...............
...............
...............
...............
...............
...............
..
Effluent
Mayfield Farm Treatment Works
Original System
Re-engineered System
Horizontal
subsurface
flow
wetlands
Balancing
Reservoir
Floating
treatment
wetlands
Primary Treatment
Secondary Treatment
Aerated Wetland Layout
Aeration Tubing Plow
Tertiary Treatment
Thank You for Your Attention