Transcript pipe and tank material degradation 2011 EWRI.pptx

Urban Stormwater Runoff Contamination
Associated with Gutter and Pipe Material Use
Olga Ogburn1 and Robert Pitt2
1 Graduate Student; Civil, Construction, and Environmental
Engineering Department; The University of Alabama
2 Ph.D., P.E., BCEE, D.WRE Cudworth Professor of Urban Water
Systems; The University of Alabama
http://www.slatetileroofing.com/gallery/images/allred_roof_systems_gallery/copper/copper_gutters.jpg
The Goal
To determine how stormwater quality is
affected by the type of gutter and pipe
materials, environmental parameters causing
degradation of the material, time of contact,
and interactions of those factors.
Prior Research
Contribution of rooftop material to runoff water
quality, for example:
– Zinc concentrations from uncoated galvanized
metal ranged between 3.5 and 9.8 mg/L (Clark,
Long et al., 2008).
– Zinc concentrations from coated galvanized metal
were below 0.5 mg/L (Clark, Long et al., 2008).
Effect of pipe material and environmental
parameters on drinking water quality, for example:
– Iron concentration from PVC pipes reached 0.058
mg/L after 3 days of exposure (Lasheen M.R.,
Sharaby, C.M., et. al, 2008).
Experimental Design
A series of long-term static leaching tests
Eight roof and pipe materials
Low and high pH condition
Natural storm water was collected in the city
of Tuscaloosa from downspouts and from
storm drain inlets.
Materials:
Gutter Materials: vinyl, aluminum, copper,
and galvanized steel.
Pipe Materials: concrete, HDPE, PVC, and
galvanized steel.
New materials
Concrete pipes - 15 cm long
The rest of pipes - 30 cm long
Experimental Design
Containers with pH values of 5 and 8 (using Na2HPO4
* 2H2O and KH2PO4 to create buffers)
Sampling times: time zero, 0.5 hr, 1 hr, 27 hr, 1 mo, 2
mo, 3 mo
Measured Parameters:
Metals (cadmium, chromium, lead, copper, zinc,
aluminum, and iron)
Toxicity (Microtox)
pH
Nutrients (ammonia nitrogen, total nitrogen, nitrate)
and COD
Mass Release per Surface Area, mg/m2
Lead Mass Release per Surface Area of a
Pipe/Gutter in Containers with pH 5 and pH 8
100
10
P. Steel pH 5
G. Steel pH 5
P. Steel pH 8
1
0.001
0.01
0.1
Time, day
1
10
0
 Lead release was observed only for galvanized steel
materials during both short and long exposure times.
 The loss of lead was higher for containers with pH 8
compared to containers with pH 5.
 The highest lead release was noted for galvanized
steel pipe at pH 8 and was between 0.628 – 0.710
mg/L (corresponds to 25 - 30 mg/m2).
G. Steel pH 8
Mass Release per Surface Area,
mg/m2
Copper Mass Release per Surface Area of a
Pipe/Gutter for Containers with pH 5
1,000
100
P. PVC pH 5
P. HDPE pH 5
P. Steel pH 5
10
G. Vinyl pH 5
G. Aluminum pH 5
1
0.001
0.01
0.1
1
10
G. Copper pH 5
0
Time, day
 The highest copper release was observed from copper
materials. After 27 hr of exposure copper release was
more than 6 mg/L (up to 970 mg/m2).
 Copper release was also found in containers with other
materials but in much lower concentrations.
Mass Release per Surface Area, mg/m2
Copper Mass Release per Surface Area of a
Pipe/Gutter for Containers with pH 8
1,000
P. PVC pH 8
100
P. HDPE pH 8
P. Steel pH 8
10
G. Vinyl pH 8
G. Aluminum pH 8
1
0.001
0.01
0.1
Time, day
1
G. Copper pH 8
10
0
 Lower and slower copper release was
observed at higher pH
G. Steel pH 8
Zinc Mass Release per Surface Area of a Pipe/Gutter
in the Containers with pH 5
Mass per Surface Area, mg/m2
1000
100
10
1
0.001
0.01
0.1
1
10
100
P. PVC pH 5
P. HDPE pH 5
P. Steel pH 5
G. Vinyl pH 5
G. Aluminum pH 5
G. Steel pH 5
G. Copper pH 5
0
Time, day
 Zinc losses were the highest for galvanized steel materials
 Copper materials were the second highest source of Zinc
release
-Reached 0.13 mg/L (16 mg/m2) after long time exposure
-Higher losses at pH 5
 Concrete and Plastic materials were the lowest source of zinc
Zinc Mass Release per Surface Area of a Pipe/Gutter
in the Containers with pH 8
Mass Release per Surface Area,
mg/m2
10000
1000
100
10
1
0.001
0.01
0.1
1
10
100
P. PVC pH 8
P. HDPE pH 8
P. Steel pH 8
G. Vinyl pH 8
G. Aluminum pH 8
G. Steel pH 8
G. Copper pH 8
P. Con pH 8
0
Time, day
 For galvanized steel materials zinc release was greater and
faster at higher pH conditions during long exposure
 After long-time exposure (90 mg/L; 4200 mg/m2 at pH 8)
Concrete and Galvanized Steel Materials
Concrete Pipes at 3 mo
0.12
Total Metal Concentration, mg/L
No metals were detected with
concrete pipes until 2 months
0.10
0.08
pH 5
0.06
pH 8
0.04
0.02
0.00
Lead
Zinc
Aluminum
Iron
Steel Gutters at 3 mo
16
16
14
14
12
10
pH 5
8
pH 8
6
4
2
Total Metal Concentration, mg/L
Total Metal Concentration, mg/L
Steel Gutters at 27 hrs
Copper
12
10
pH 5
8
pH 8
6
4
2
0
0
Lead
Copper
Zinc
Lead
Copper
Zinc
Aluminum
Iron
Aluminum and Copper Materials
Aluminum Gutters at 27 hrs
Aluminum Gutters at 3 mo
0.45
0.020
0.015
pH 5
0.010
pH 8
0.005
Total Metal Concentration, mg/L
Total Metal Concentration, mg/L
0.025
0.000
0.40
0.35
0.30
0.25
pH 5
0.20
pH 8
0.15
0.10
0.05
0.00
Lead
Copper
Zinc
Lead
Copper Gutters at 27 hrs
Zinc
Aluminum
Iron
Copper Gutters at 3 mo
6
7
6
5
pH 5
4
pH 8
3
2
1
0
Total Metal Concentration, mg/L
8
Total Metal Concentration, mg/L
Copper
5
4
pH 5
3
pH 8
2
1
0
Lead
Copper
Zinc
Lead
Copper
Zinc
Aluminum
Iron
Toxicity
Gutters pH 8 @ 5 min
 At higher pH conditions
80
% Effect
Concrete and Vinyl
materials – least toxic
Copper and PVC – most
toxic
100
0.01
G. Aluminum pH 8
60
G. Aluminum pH 8
40
G. Copper pH 8
20
G. Copper pH 8
G. Steel pH 8
0
0.1
-20
1
10
100
1000
10000
G. Vinyl pH 8
-40
G. Vinyl pH 8
-60
Time, hr
pH measurements for containers
with pH 8
Pipes pH 8 @ 5 min
10
100
9
7
P. HDPE
6
P. Steel
40
P. HDPE pH 8
5
G. Vinyl
20
P. HDPE pH 8
4
G. Aluminum
% Effect
pH, unitless
P. Concrete pH 8
60
3
G. Steel
0.01
2
G. Copper
1
0.1
80
P. PVC
8
0.01
G. Steel pH 8
1
10
Time, hr
100
1000
10000
P. Concrete
P. Concrete pH 8
P. PVC pH 8
0
0.1
-20
1
10
1000
10000
P. PVC pH 8
P. Steel pH 8
-40
-60
100
P. Steel pH 8
Time, hr
Conclusions
The greatest source of lead, zinc, and iron were
galvanized steel materials, while copper materials
were the highest source of copper.
Lead and Zinc release was detected during both
short and long exposure .
During short exposure time copper releases were
detected only for copper materials at both low
and high pH
Copper and aluminum materials had the highest
toxicity, while concrete materials were least toxic.
References
 Clark, Shirley E., Long Brett V., Siu Christina Y.S., Spicher Julia, Steele Kelly
A., 2008 Runoff Quality from Roofing during Early Life. Water Environment
Federation.
 Lasheen M.R., C.M. Sharaby, N.G. El-Kholy, I. Y. Elsherif, S. T. El-Wakeel,
2008. Factors influencing lead and iron release from some Egyptian
drinking water pipes. Journal of Hazardous Materials. 160 (2008) 675-680
 http://www.slatetileroofing.com/gallery/images/allred_roof_systems_gall
ery/copper/copper_gutters.jpg
 http://www.guttersupply.com/file_area/public/categories/ImageUrl_1202
397996_9640.jpg
Acknowledgements
 NSF EPSCoR
Thank you!