Selected Summaries of Recent and On-Going Projects
Contents
1. Stormwater Non-potable Beneficial Uses and Effects on Urban Infrastructure, Water Environment
Research Foundation and US EPA, 2009 – 2012 ........................................................................................... 1
1.1 Groundwater Impacts from Seepage Wells used for the Disposal of Stormwater ............................ 2
2. Field Monitoring of Up-Flo Filter - Bama Belle Site, HydroInternational, 2009 – 2013 ............................ 4
3. Identification and Treatment of Emerging Contaminants in Wet Weather Flows, US Environmental
Protection Agency, 2007 - 2013 .................................................................................................................... 6
4. Environmental Contamination Sensor Development and Evaluations Associated with Natural
Disasters; NSF and the Center for Optical Sensors and Spectroscopies (COSS), University of Alabama at
Birmingham, 2008 – 2014 ............................................................................................................................. 8
4.1 PAH Contamination from Newly Paved Surfaces ............................................................................. 11
4.2 Heavy Metal Releases from Alternative Drainage System Components .......................................... 11
4.3 Urban Wildlife Bacteria Sources and Survival in the Environment ................................................... 12
5. Biofiltration Media Evaluation; Geosyntec Consultants and Boeing Co., 2008 – 2012 .......................... 13
5.1 Enhanced Underdrain Systems for Biofilters .................................................................................... 16
6. National Demonstration of Advanced Drainage Concepts using Green Solutions for CSO Control; US
EPA and TetraTech, 2008 – 2013 ................................................................................................................ 18
6.1 Stormwater Controls to Satisfy Developing Regulations .................................................................. 21
7. National Stormwater Quality Database, US EPA, 2001 – 2011............................................................... 25
8. Detection and Corrections of Inappropriate Discharges to Stormwater Drainage Systems, US EPA,
2001 – 2008 ................................................................................................................................................ 25
9. Relationships Between the Variability of Stormwater Characteristics and Development Characteristics
.................................................................................................................................................................... 25
10. Heavy Metal Contamination of Soils in Treated Wood Burn Areas ...................................................... 26
11. Stormwater Quality Modeling .............................................................................................................. 28
12. Compaction of Urban Soils.................................................................................................................... 28
1. Stormwater Non-potable Beneficial Uses and Effects on Urban Infrastructure,
Water Environment Research Foundation and US EPA, 2009 – 2012
The examination of stormwater beneficial uses involves a number of steps and tools. This project shows
how currently available models and other tools can be interactively used to calculate the quality and
quantity benefits of stormwater reuse. Besides the obvious benefit of reduced stormwater discharges
(and attendant receiving water benefits), many reuse options also benefit other components of the
urban water infrastructure. If stormwater is stored and used to irrigate landscaped areas and flush
1
toilets, as is common in many locations today, less highly treated domestic water needs to be delivered.
Grey water systems, where partial treatment of some household wastewaters allows that water to be
used for non-potable use, also results in smaller sanitary wastewater sewage collection and treatment
systems. General household water conservation also has been shown to reduce wastewater discharges,
in addition to reducing domestic water deliveries. Firefighting water demands usually requires the
construction of much larger water lines than needed to supply in-building uses. In earthquake-prone
areas, on-site storage of firefighting water in stormwater wet detention ponds has been shown to be
more reliable than the municipal water supply system. In many areas of Western Europe, large-scale
infiltration of stormwater has been demonstrated to dramatically reduce the volumes of combined
sewage needing treatment during wet weather. In Japan, infiltration of stormwater, initially used to also
reduce CSO problems, has also been shown to have dramatic benefits on local groundwater recharge.
1.1 Groundwater Impacts from Seepage Wells used for the Disposal of Stormwater
One of the case studies being examined as part of this WERF project is located in Millburn, NJ. Dry
wells/seepage pits have been used since 1999 on new construction (and extensive remodeling) of
homes in Millburn, NJ, to infiltrate the additional runoff associated with the new construction. An EPA
demonstration project is examining the effectiveness of these infiltration devices in reducing discharges
to the storm drainage system, and to document any problems associated with their use. Millburn has
separate sewers, but there is concern about drainage problems developing in areas of new construction.
About 1,500 homes have drywells and some of these also have tanks before the drywells for irrigation
reuse withdrawals. The groundwater table is as shallow as 8 to 10 ft along the river in town. The soils
vary greatly in the community, with a lot of clayey soils. Our WERF project used the basic information
and data and conducted further analyses and modeling.
Peerless Concrete Products, Butler, NJ
supplies the dry wells to many of the sites in
Millburn (photo from
http://www.peerlessconcrete.com/)
Installed drywell in Millburn, NJ, showing the
surrounding stone, before completion of the
backfilling
2
Underground water storage cistern in
Millburn, NJ
Pump for irrigation system
Modeling showed that the cisterns provide an overall runoff reduction of about 24% for each home.
Because of the relatively poor soils in the area and the large amounts of landscaping for the large lots,
most of the runoff originates from the small landscaped areas that are not treated by these controls.
The natural runoff from this area is also relatively high due to the soils. When compacted during the
construction activities and general land use activities, soils with some clay become quite impermeable.
These drywells provide much of their infiltration benefits at lower depths that are not subjected to the
compacted.
160
10/02/2009
10/12/2009
140
120
100
Depth (cm)
80
07/31/2009
08/02/2009
60
40
08/02/2009
08/06/2009
07/29/2009
07/31/2009
20
0
-20
0
500
1000
1500
2000
Time (hr)
Monitored water levels in dry well in Millburn, NJ.
3
2. Field Monitoring of Up-Flo Filter - Bama Belle Site, HydroInternational, 2009 –
2013
Treatment of stormwater requires a device that can remove many types of pollutants as well as large
amounts of debris and floatable materials, over a wide range of flows. Filtration is one tool being used in
many areas to remove a wide range of stormwater pollutants. The objective of this research is to
examine the removal capacities of a recently developed stormwater filtration device, in part developed
by engineers at the University of Alabama through a Small Business Innovative Research (SBIR) grant
from the U.S. Environmental Protection Agency. The Up-Flo® Filter is an efficient high-rate stormwater
filtration technology designed for the removal of trash, sediments, nutrients, metals and hydrocarbons
from stormwater runoff. Compared with the traditional downflow filtration treatment, the upflow
filtration method reduces clogging and was developed to remove a broad range of stormwater
pollutants, especially those associated with particulates. The high flow rate capacities of the Up-Flo®
Filter are accomplished through controlled fluidization of the filtration media, while still capturing very
small particulates through a flexible, but constraining, media container. The Up-Flo® Filter also drains
down between rain events which minimizes anaerobic conditions in the media and which also partially
flushes captured particulates from the media to the storage sump, decreasing clogging and increasing
run times between maintenance. Gross floatables are captured through the use of an angled screen
before the media and a hood on the overflow siphon, while the sump captures bed load particulates.
The full-sized Up-Flo filter is being tested with six modules in Tuscaloosa, AL. A 7-foot tall 4-foot
diameter Up-Flo TM Filter has been installed at the Riverwalk parking lot near the Bama Belle on the
Black Warrior River. The system receives surface runoff from a 1 acre site that includes a parking lot,
driveways, sidewalks, and a small landscaped area. The system was installed for the purpose of
determining the hydraulic capacity and the pollutant removal capabilities in a full-scale field installation
under both controlled and actual runoff conditions.
4
Cut-away of an installed Up-FloTM filter
(HydroInternational drawing).
Flow paths in the Up-FloTM filter
(HydroInternational drawing).
Head (in) vs. Flow Rate for CPZ Media (gal/min)
Upper Confidence in 95%
Actual Data
Lower Confidence in 95%
Linear (Actual Data)
Flow Rate (gal/min)
140
120
100
80
60
y = 6.9449x
40
2
R = 0.6918
20
0
0
5
10
15
20
Head (in)
Interior of monitoring box (without samplers,
but with batteries, data recorders, and
sondes).
Flow vs. head graph for CPZ media indicating high
treatment flow rates for small filter areas.
5
Probability plots showing significant removal
of very small particles.
UpFlo filter performance during controlled
tests.
3. Identification and Treatment of Emerging Contaminants in Wet Weather
Flows, US Environmental Protection Agency, 2007 - 2013
The presence of emerging contaminants (ECs) in wet weather flows (WWFs) has not been welldocumented, while there has been extensive efforts investing these compounds in wastewater
discharges, water systems, and in natural waters. The initial project activities focused on an extensive
literature review of emerging contaminants in wet weather flows, specifically separate stormwater,
combined sewer overflows (CSOs), and sanitary sewer overflows (SSOs). Characterization (presence and
concentrations) of ECs in wet weather flows and on their treatment is of the most concern for this
project. Although little information exists for separate stormwater, much more exists for sanitary
wastewaters and surface waters. This information allowed us to identify which constituent categories
are likely present in wet weather flows, and in what concentrations. Much information exists for
treatment of ECs in municipal wastewater treatment facilities, and in public water treatment plants.
From this literature information, we are developing a simple screening tool that will consider the likely
presence of the different ECs in the three WWFs of interest, and their treatability by typical and
advanced unit processes applicable to WWFs.
Influent
After primary treatment
6
Final effluent
After secondary treatment
Tuscaloosa Wastewater Treatment Plant PAHs during rain event #1.
The following are some of the pharmaceutical and personal care products (PPCPs) for which our project
team have developed analytical methods for contaminated surface waters. We are evaluating selected
compounds in our analytical scheme:
Ibuprofen
Diltiazem hydrochloride
Gemfibrozil
5,5-Diphenly hydentoin
Divalproate sodium
Dichlofenac
Caffeine
Trimethoprim
Triclosan
In addition, estrogen, common veterinary medications, along with some lotions and fragrances are
being added to our list, depending on reported frequency and concentrations from the literature, and
the likelihood of their presence in WWFs. The analyses of characterization samples are being conducted
using HPLC and GC/MSD. Pesticides are being analyzed using GC/ECD, while heavy metals are being
examined using a variety of methods (ICP and ICP/MS).
The analytical scheme includes sampling at a wastewater treatment plants during wet weather. The
treatment plant is a separate sanitary sewage treatment facility, but is affected by typical infiltration and
inflow, or I&I during large flows. Source area samples in different land uses are also being collected.
About 50 source area sheetflow samples are being collected during many different rains. Four locations
at the wastewater treatment facilities are also being sampled during seven rains and seven dry weather
periods. This information, along with specialized laboratory tests, is being used to identify treatability of
the ECs found in wet weather flows.
7
0
2
4
6
8
10
12
14
Minutes
16
18
20
22
24
26
28
0
30
Minutes
12
60
30
0
14
2
4
16
6
18
20
40
8
10
20
Pk #
Area
Retention Time
SPD-M20A-263 nm
0510Final010116Acid
12
22
10
0
14
16
24
20
18
20
26
22
24
26
28
mAu
40
21 63438 23.088
15697 23.492
22686 23.960
22
23 14424 24.448
24
25.420
25 1436825.728
7117 26.328
26
26.532
1641
27 4639
27.000
28 1806 27.368
29 2638 27.744
30 4721
31
28.704
32 26622
10723 28.972
29.300
29.592
5268
33 10458
34
35
36
40
19.880
12
11
18.852
8
18.468
705924
19.484
450352
325656
241514
27
47184 26.560
27.024
289712 27.364
29 2434
37928 27.732
28.008
30
8390
31
44133 28.624
32
29253 28.916
104927
29.280
33
34
35
mAu
16.296
19.684
17.408
1005924
6
643625
16.740
317822
13
20.164
14
261643
20.712
137392
16 20.968
319533
17
21.420
18
57416 21.784
215801
19
22.144
20
21 139027
23.084
40733 23.456
22
23.992
23 26383
35350 24.352
24
25
12985 25.416
25.744
26 6754
651031
5
176887
15.536
12.960
194623
140950
2
14.428
1027515
1131617 17.628 7
18.024
15.112
3
142916
60
97608 13.416
1
80
15
20
819074
mAu
SPD-M20A-263 nm
0510Prim010116Acid
1612
14.232
832714.508
3
22366 14.952
4 687
48771 15.552
5
15.764
6
195960
16.308
7
138021
167221 16.772
17.172
9 1 8
209190
10
17.584
11
12
191337
18.508
300781
13
28584518.908
19.192
97425 19.524
15
19.928
16
17
8961
20.724
31880 18
19
181195
20
21.904
Influent
mAu
80
Pk #
Area
Retention Time
2
19.480
16.400
120
9
10
38
61154 28.708
54432 28.984
36
29.508
37 26871
35
27.096
32 7967 27.432
33 1494
65616 27.820
34
12720 25.468
25.800
30 7483
31
50261 26.652
20
16480 12.500
14389 13.068
19796 13.444
13.772
4
33146 24.468
28
29
60
mAu
26
mAu
24
38 485
39
22
22 56186 23.076
17187 23.500
23.932
26229
23
24.424
24 11637
24.972
25
13097 25.408
26 1484
25.740
27 7002
26.336
28
26.520
1824 26.700
29 2100
1314 26.968
30 1939 27.348
31
2401 27.728
32
33
7397
34
28.736
35
29664 28.952
8918
29.564
36 15028
29.900
37
19.984
972654
269809
15
14
1443008
100
18.068
20
20
1
SPD-M20A-263 nm
0510Second010116Acid
18.072
Pk #
Area
Retention Time
16452432
20.276
75336 20.576
13602 20.784
18
231731
21.136
19
445163
20
21.532
406030
21
21.860
206046
22
22.248
23
22.736
24
1575
167330
23.160
25
61777 23.520
26
27 70325 24.072
1573178
17.232
9
15.616
18.536
411595
18.916
301419
8
15.260
92586 463964
SPD-M20A-263 nm
0510Influ010116Acid
406059
10
16.280
18
432884
16
14
0
267524
30
14
776738
1366333
17.532
1364187 17.772
10
18.092
20
15
11
12
7
13.108
13.368
3386 157806 13.668
2
3 41064 14.340
4
62425 14.648
80
17
11
12
13
40
20339 12.776
139770
60
5
6
1
mAu
100
Pk #
Area
Retention Time
26432 13.064
55888 13.420
33528 13.748
14.012
14.232
61832 14.480
1
29555
127748
2 323
14.932
3 21619 15.344
45
21819 15.560
35799 15.824
6
7
8
87648 16.772
10
9 106588
17.172
128132
17.592
12
114497
13
18.500
180631
14
15665818.912
19.204
273096
19.536
16185962
19.936
17
18
20.724
4220219
20
123186
21
21.892
mAu
120
80
60
40
20
28
Minutes
28
After primary treatment
60
40
20
0
Minutes
30
After secondary treatment
Effluent
HPLC analyses for other organic ECs for first event at the Tuscaloosa treatment plant. Compounds
commonly identified include the acidic pharmaceuticals sulfamethoxole, trimethoprim,
carbamezapine, and fluoxetine.
4. Environmental Contamination Sensor Development and Evaluations
Associated with Natural Disasters; NSF and the Center for Optical Sensors and
Spectroscopies (COSS), University of Alabama at Birmingham, 2008 – 2014
The mission of the Center for Optical Sensors and Spectroscopies (COSS) is to promote optical sensing
and spectroscopy research on environmental, biomedical, and national security issues through
8
collaborative use of resources and expertise among the member universities, government and industrial
laboratories, and improve sensor techniques using recently developed revolutionary laser and
spectroscopic technologies. The Deep Water Horizon oil spill off of the southeast coast affecting LA, MS,
AL, and FL has highlighted the critical need for rapid environmental monitoring of hazardous wastes and
other pollutants. In the last year, COSS environmental researchers associated with the Environmental
Institute at UA have been developing and testing methods that can be used to rapidly detect the extent
of contamination of spills and discharges of hazardous organic compounds. This work is also
investigating the problems associated with the aftermath of these accidents such as determining the
potential hazards to responders and residents of the affected areas. Long-term potential contamination
of aquatic organisms and the food supply is also of concern that can be better examined using the newly
developed methods. The COSS laser-based “optical nose” being developed as part of this NSFsupported research will enable rapid and sensitive measurements of these compounds during, and
after, these types of environmental disasters.
Our on-going research as part of our COSS activities has been to investigate the sources, fate, and
treatment of toxicants, including organic contaminants of most interest to the COSS laser facility. We
focused on a wide range of materials, from PAHs and other petroleum hydrocarbons, to heavy metals,
and radioactive materials. The work with the organic compounds will enable us to develop and test
analytical methods that can be used in times of environmental disasters or homeland security incidents,
specifically to obtain rapid data that is currently not available. We initiated this research direction in the
aftermath of several severe hurricanes in the gulf coast a few years ago. The unfortunate major oil spill
in the gulf is another example of the dramatic need for rapid and reliable information.
As part of this effort, we acquired a scanning FTIR spectrophotometer and developed methods to obtain
analytical spectra in the range of interest to the COSS laser instrumentation during exposure
experiments to quantify losses of critical organic contaminants to the environment, and several very
successful outreach activities conducted in conjunction with other NSF projects. The most common IR
wavelengths used for analytical purposes for the organic compounds of interest fall outside of the 2 µm
(5,000 cm-1) to 3.6 µm (2,800 cm-1) operational range of infrared laser instrumentation. Secondary
wavelengths exist in this range, but have not been well documented in the literature. Most of the
compounds investigated during the method development phase involved solvents, as shown below for
MEK. Research was expended to investigate heavier hydrocarbons and crude oil.
Perkin Elmer Spectrun Rx 1 scanning FTIR
FTIR scan of Methyl Ethyl Ketone in the range of 2000
to 4500 cm-1
9
We are also working with Miles College in Birmingham to develop methods using their HPLC and GC/MS
equipment to simultaneously quantify the organic compounds that we are investigating during our
exposure experiments. Exposure experiments examined the releases of toxic PAH compounds from
different asphalt mixtures during the first several months of use, the period when we expect most of
these releases to occur. Fate modeling of the organic compounds of interest is used to identify which
are likely to cause the most harmful effects, and which can be treated by conventional and advanced
wastewater and water treatment methods. The fate of discharged or spilled contaminants was also
investigated using fugacity modeling verified by field investigations.
99.9
99
95
90
Percent
80
70
60
50
40
30
20
10
5
1
0.1
0
3
6
9
12
Effect
Effects and interactions on Nystatin migration in
vadose zone (rainfall and intrinsic permeability
most significant, interacting together and
separately)
HPLC at Miles College used to quantify emerging
organic contaminants
3
1.112 1.585
2
1
2
3
4
5
6
7
mVolts
1.586 2.262
1
0
0.000 0.000
0.000 0.000
0.000 0.000
Benzo[g,h,i]perylene
1.827 2.606
Dibenzo[a,h]anthracene
0.000 0.000
Indeno[1,2,3-c,d]pyrene
(Benzo[a]pyrene)
0.000 0.000
Benzo[b]fluoranthene
Benzo[k]fluoranthene
2.455 3.501
0.000 0.000
0.000 0.000
0.000 0.000
0.000 0.000
Chrysene
0.000 0.000
0.000 0.000
0.000 0.000
0.000 0.000
Fluoranthene
0.000 0.000
0.0000.000
0.0000.000
0.000 0.000
-3
1.395 1.989
0.000
0.000
Pyrene
3.177 4.530
0.000 0.000
0.000
0.000
1.082 1.542
1.747 2.491
Anthracene
0.969 1.382
0.783 1.116
Flourene
-2
0.000 0.000
Acenaphthene
0.000 0.000
0.000
0.000 0.000
0.000
0.000 0.000
Naphthalene
0.000 0.000
0.000 0.000
-1
0.000 0.000
0.000 0.000
0.000 0.000
0.208 0.297
Acenaphthylene
0
4.505 6.424
1.590BDL
0.000 1.115
BDL 0.000
mVolts
0.000 0.000
1
0.000 0.000
2
4
Benz[a]anthracene
Phenanthrene
0.000 0.000
0.000 0.000
3
10.597 15.113
Nam e
EST D concentrati on
NORM concentrati on
37.564 53.570
FID
PAHStd09290320A
4
-1
-2
-3
8
9
10
11
12
13
Minutes
GC/MSD chromatograph showing large concentrations of several compounds of interest (especially
phenanthrene, benz[a]anthracene, indeno[1,2,3-c,d]pyrene, and dibenzo[a,h]anthracene).
10
One example of an experiment being conducted as part of this research is briefly described below:
4.1 PAH Contamination from Newly Paved Surfaces
These tests were performed under actual environmental conditions to examine the organic and heavy
metal content of runoff from newly installed asphalt pavements and to observe changes in their
concentrations with aging during the first several months of exposure. During the life of a pavement, it
undergoes aging and hardening due to exposure to temperature, air, and moisture in the environment.
This results in the loss of some pavement components by volatilization and irreversible changes in
composition by reaction with atmospheric oxygen. Asphalt contains PAHs and heavy metals that
represent potential contaminants in water runoff. In addition to PAHs and metals, nutrients, other
organic and inorganic toxicants also leach into the runoff when rain water comes in contact with the
pavement surface. This study focused on the changes in leaching of these compounds (PAHs, the heavy
metals Cd, Cr, Cu, Pb and Zn, and selected nutrients and toxicity) of the runoff from the pavement
during initial pavement aging, a period when the most rapid changes occur, and when the runoff is
expected to be the most toxic.
4.2 Heavy Metal Releases from Alternative Drainage System Components
The goal of this research is to determine: (1) how contaminants in pipe materials affected the quality of
the water and to identify the environmental parameters causing degradation of the material, contact
time, and interactions of these factors, and (2) contributions of roof runoff contamination caused by
atmospheric deposition. The contaminants being studied include heavy metals, toxicity, nitrates, and
phosphates. Prior research has been performed on the contributions of rooftop material to runoff water
quality. Results show that the roof runoff quality is dependent on the type of roofing materials used.
Little data is available to indicate how piping materials and environmental parameters influence storm
water quality. This on-going research is investigating long-term leaching of these compounds from
several gutter materials (galvanized aluminum, vinyl, copper, and galvanized steel) and pipe materials
(concrete, high-density polyethylene, poly vinyl chloride, and galvanized corrugated steel). Full-sized
samples of these materials are being soaked in buffered low and high pH test solutions, at high and low
conductivity, with water samples withdrawn every few days for analyses.
Copper roof drains and
downspouts
Vinyl roof drains and
downspouts
Concrete is the most
common currently used
piping material
11
Total zinc concentrations in containers with river water.
4.3 Urban Wildlife Bacteria Sources and Survival in the Environment
As noted above, additional research tasks during this emerging contaminant project are examining
sources and movement of urban area bacteria. Sewage-borne pathogen contamination of urban
receiving waters constitutes risk to health. Risks have traditionally been evaluated on the basis of
indicator species, microorganisms assumed to have come from sanitary-sewage contamination of the
watershed and assumed to indicate the presence of sewage-borne pathogens. Sources other than
sewage (e.g., animal feces and soil storage) also contribute to indicator-species assemblages in urban
runoff. Accurate assessment of health risk from runoff requires knowledge of these other sources. This
research component is analyzing the non-sewage components of microbial indicator species from
source areas of various land uses, the potential for mobilization of those species into sheetflow by
rainfall, and the particle/surface associations likely to affect transport of those species through the
watershed.
12
Survival of E. coli under varying environmental conditions. Warm, wet, and dark conditions allow the
bacteria to thrive compared to other conditions which result in much greater reductions of their
populations.
5. Biofiltration Media Evaluation; Geosyntec Consultants and Boeing Co., 2008 –
2012
This study investigated a variety of media types that can be used singly and in combination for use in
stormwater treatment facilities, including media filters, biofilters, bioretention, rain gardens, etc. These
tests were conducted specifically to determine the different media performance options for use in
advanced biofiltration systems at an industrial site having very stringent numeric effluent limits. These
stormwater treatment systems were designed to treat 90% of the long-term runoff volume from
drainage areas ranging from 5 to 60 acres at the site. The main pollutants of interest for the project are
cadmium, copper, lead, and dioxins, with other constituents being of secondary interest, based on
historic stormwater quality monitoring results at the site. One primary project objective is for treated
effluent concentrations to meet the low numeric effluent limits that have been applied to stormwater
discharges through the site’s NPDES permit. These numeric effluent limits are based on water quality
standards. A challenge to the project design is that current site runoff concentrations for the pollutants
of interest are generally below levels typically seen in urban and industrial stormwater runoff. A review
of the literature on filtration media and onsite monitoring data (including existing treatment system
performance results and previous media pilot testing studies) indicated that several promising media
exist for consistently treating the pollutants of interest to the required effluent concentrations.
However, many of these materials are very expensive; with potential construction costs being significant
given the large volumes required for the systems based on early designs (estimated media volumes for
the project have ranged from 5,000 – 12,000 cubic yards). There are newly available materials that are
promising, but little, if any, data are available to quantify their performance. These tests therefore
13
evaluated these candidate materials under procedures that have proven successful during past media
investigations for stormwater treatment effectiveness.
Observed infiltration and clogging characteristics for tested media.
Media mixtures performed more consistently under a broader range of conditions than individual
components used separately. The mixtures capitalize on the pollutant removal strengths of their
components, while providing other components that may address the weaknesses (such as the release
of cations in large concentrations during ion exchange). The media mixtures that are most robust
(longest run times before clogging, with moderate flow rates and suitable contact times for pollutant
removal) are:

Rhyolite sand, SMZ, and GAC mixture (blended mixture) and the Rhyolite sand, SMZ, GAC-PM
mixture (blended mixture). They had very similar performance attributes. The added peat provided
some additional benefits for metal reductions at high flow rates. The GAC in these mixtures (when
mixed with the other components) also provided better control for a number of other constituents,
including nitrates.

Site filter sand-GAC-site Zeolite (layered) clogged earlier, but possibly would have fewer
exceedences overall. The drawback to the layering of the filter components is the change in flow
rate and contact time.
In terms of statistically significant removals, both R-SMZ-GAC and S-Z-GAC (layered) media combinations
performed similarly, although the current site layered media combination did not demonstrate
14
statistically significant removals for lead. Any media combination that included GAC was effective for
TCDD removal. All of the media tested had very high levels (approaching 90%) of removals of
particulates, even down to very small particle sizes (as small as 3 µm), with concurrent good removals of
pollutants strongly associated with the particulates (such as for total aluminum, iron, and lead).
Media performance plots for copper from long-term, full-depth column tests.
Some constituents and some media required a certain contact time before retention, while others were
more capable of pollutant retention more rapidly and at lower influent concentrations. For example,
when the contact time was less than 10 minutes, the metal removals were much less than for the longer
contact times. Also, greater contact with GAC resulted in slightly better nitrate removals, while the
greater contact time for phosphate resulted in greater losses of the phosphate from the media. This
type of trade-off between improved removal and increased leaching was seen for several mediaconstituent combinations.
Longer retention times can be achieved through deeper media beds or slower flow rates and larger
surface areas. The column tests confirmed generally the results of the laboratory studies that showed
that good removals could be achieved with relatively slow to moderate flow rates (5 to 60 meters/day)
and moderate contact times of the water with the media (10 to 40 minutes).
15
Media performance plots for lead from varying-depth column tests.
The GAC was the most important component in these mixtures, while the addition of either of the
zeolites was also needed. The specific choice of which would be dependent on costs and specific ion
exchange issues. The sand is critical to moderate the flow rates and to increase the contact times with
the coarser media, unless other flow controls were used in the filter designs. The Rhyolite sand added
some removal benefits compared to the site sand. As noted, a small amount of peat added to the
mixture increases metal removals during high flow rates. Therefore, the best mixture for removal of
pollutants to levels that met the effluent discharge limits was the combination of Rhyolite sand (30%),
surface modified zeolite (30%), GAC (30%), and approximately 10% peat. To minimize the leaching of
constituents from the GAC, its concentration could be reduced, but then nitrate removals would be
limited.
5.1 Enhanced Underdrain Systems for Biofilters
The treatment of stormwater by biofilters is dependent on the hydraulic residence time in the device for
some critical pollutants. The effective use of biofilters for the control of stormwater in combined
sewered areas is also related to residence time, as it is desired to retain the water before discharge to
the drainage system in order to reduce the peak flows to the treatment plant. This research is
conducting a series of tests to determine the hydraulic characteristics of sand-based filter media (having
a variety of particles sizes representing a range of median particle sizes and uniformity coefficients)
during pilot-scale trench tests. The drainage rate in biofiltration devices is usually controlled using an
underdrain that is restricted with a small orifice or other flow-moderating component. These frequently
fail as the orifices are usually very small (<10 mm) and are prone to clogging. A series of tests were also
conducted using a newly developed foundation drain material (SmartDrainTM) that offers promise as a
low flow control device with minimal clogging potential. A pilot-scale biofilter using a trough 3m long
and 0.6 x 0.6m in cross section is being used to test the variables affecting the drainage characteristics of
16
the underdrain material (such as length, slope, hydraulic head, and type of sand media). Current tests
are also being conducted to test the clogging potential of this drainage material.
SmartDrainTM installed in pilot-scale biofilter.
The results from the experiments conducted to test the variables affecting the drainage characteristics
of the filter media indicate that slope of the SmartDrainTM material had no significant effect on the
stage-discharge relationship whereas effect of length of the SmartDrainTM material had a very small
effect on the discharge. Research is ongoing to investigate the clogging potential of the SmartDrainTM
material. Only about 20% reductions in the outflow rate of the filter media have been observed during
the clogging tests having a total load of about 40 kg/m2 onto the filter area, about twice the load that
can usually cause clogging of biofilter media.
Reduction in flow with increased sediment loading.
17
0.14
Orifice
0.25 inches
Flow rate (L/s)
0.12
0.1
Orifice
0.20 inches
Smart Drain
1.25 ft
clean water
0.08
0.06
Smart Drain
1.25 ft
dirty water
Smart Drain
1.1 to 9.4 ft
0.04
0.02
Orifice
0.1 inches
0
0
0.2
0.4
0.6
Head (m)
0.8
1
1.2
SmartDrainTM flow rates compared to very small orifices.
Turbidity (NTU) measurements showed that the effluent NTU decreased rapidly with time, indicating
significant retention of silt in the test biofilter during the clogging tests. These preliminary tests indicate
that the SmartDrainTM material provides an additional option for biofilters, having minimal clogging
potential while also providing very low discharge rates.
6. National Demonstration of Advanced Drainage Concepts using Green
Solutions for CSO Control; US EPA and TetraTech, 2008 – 2013
The Kansas City demonstration project on the use of “green infrastructure” to minimize combined sewer
overflows (funded by the US EPA and supported by a wide range of national and local agencies) uses a
variety of integrated practices and modeling approaches. “Green infrastructure” includes a wide variety
of stormwater runoff volume and pollutant reduction tools that can be applied in existing urban areas.
Those being examined during this project include beneficial use of runoff, rain gardens, and biofilters.
This extensive project is collecting data before, during, and after implementation of a variety of control
practices in a 100 acre test watershed, and in a parallel control site. The reduction of discharges to the
drainage system during wet weather will be calculated using models and verified through field
monitoring. The continuous models determine the decreased amount of stormwater discharged for
each event as the storage and infiltration facilities dynamically fill and drain over an extended period of
time. Both developed stormwater and combined sewersheds can benefit from the added storage from
areas retrofitted with bioretention cells or rain gardens and other management practices, e.g., inlet
retrofits or curb-cuts with tree plantings.
18
Kansas City curb cut biofilter with monitoring station.
Kansas City porous concrete sidewalk
in study area.
The overall key project objectives are to:
 Demonstrate the integration of green solutions with traditional gray infrastructure in an urbancore neighborhood having a combined sewer system
 Develop a methodology for implementation of Green Solutions
 Measure the changes in the peak flow, total volume and pollutant mass of storm events in the
receiving system or the reduction of combined wastewater volumes, pollutant loads and overflows
 Develop a model for predicting the quality and quantity benefits of implementing Green Solutions
 Compare economic costs and benefits of integrated green and gray solutions
Percentage reduction in
annual roof runoff
100
Percent reduction
80
60
40
20
0
0.1
1
10
100
Percent of roof area as rain garden
Percentage reduction in annual runoff from
directly connected roofs with the use of
rain gardens.
100
80
60
40
20
0
0.001
0.01
0.1
1
Rain barrel/tank storage (ft3 per ft2 of roof area)
Reduction of annual runoff from directly
connected roofs with the use of runoff storage
and irrigation.
19
The watershed model (WinSLAMM) and the sewerage model (SWMM) are being calibrated for this area
using the pre-construction flow and water quality data. Both dry and wet weather flow data are being
recorded. The calibrated models were used early in the project to predict the benefits of the upland
controls, and these predictions are being verified as the controls are installed. After the models are
calibrated and verified for the demonstration area, they will be used to predict the benefits of wider
application of the upland controls across the city. Specifically, the models will predict the decreased
runoff volumes and peak runoff rates associated with upland stormwater controls to alleviate problems
in the combined sewer system. Water quality benefits associated with stormwater pollutant discharge
reductions of wet-weather flow particulates (including particle size distributions), nutrients, bacteria,
and heavy metals are being quantified. WinSLAMM is used to calculate the stormwater contributions to
the combined sewerage system during wet-weather by providing a time series of flows and water
quality conditions, for various types of upland controls, while SWMM, with its detailed hydraulic
modeling capabilities, focuses on the interaction of these time series data with the sewerage flows and
detailed hydraulic conditions in the drainage system. Both models will be used interactively
emphasizing their respective strengths.
The land survey found that about 65% of the area is landscaped, with most being in turf grass in poor to
good condition. This information was used in conjunction with regional evapotranspiration data to
calculate the amount of supplemental irrigation needed to meet the ET requirements of typical turf
grass, considering the long-term rainfall patterns. Most of the supplemental irrigation would be needed
during the months of July and August, while excess rainfall occurs in October through December
(compared to ET requirements during these relatively dormant months). A single 35 gallon rain barrel
per home is expected to reduce the total annual runoff by about 24% from the directly connected roofs,
if the water use could be closely regulated to match the irrigation requirements. If four rain barrels per
home were used (such as one on each corner of a house receiving runoff from separate roof
downspouts), the total annual volume reductions could be as high as about 40%. Larger storage
quantities result in increased beneficial usage, but likely require larger water tanks. Water use from a
single water tank is also easier to control through soil moisture sensors and can be integrated with
landscaping irrigation systems for almost automatic operation. A small tank about 5 ft in diameter and 6
ft in height is expected to result in about 75% total annual runoff reductions, while a larger 10ft
diameter tank 6 ft tall could approach complete roof runoff control.
The use of rain barrels and rain gardens together at a home is more robust than using either method
alone: the rain barrels would overflow into the rain gardens, so their irrigation use is not quite as critical.
In order to obtain reductions of about 90% in the total annual runoff, it is necessary to have at least one
rain garden per house, unless the number of rain barrels exceeds about 25 (or 1 small water tank) per
house. In that case, the rain gardens can be reduced to about 80 ft2 per house.
20
80
60
40
100
20
4
0
0
# of rain barrels per house
Reduction in annual roof runoff (%)
100
# of rain gardens per house
Reduction in annual runoff from directly connected roofs with the use of rain gardens
and roof runoff storage and irrigation.
The “best” combination of control options is not necessarily obvious. The CSO program must meet their
permit requirements that specify certain amounts of upland storage in the watershed. Other elements,
including costs, aesthetics, improvements to street-side infrastructure, and other benefits, also need to
be considered in a decision analysis framework.
6.1 Stormwater Controls to Satisfy Developing Regulations
Newly proposed stormwater regulations being promulgated by state and federal regulatory agencies are
stressing significant reductions in runoff volumes for new development, even areas of poor soils. Many
of the above research projects, along with our past research results, have been incorporated into
stormwater management models and demonstration projects that can show how these regulations can
be addressed. However, it is important that various precautions are considered in challenging
conditions.
The Energy Independence and Security Act of 2007” was signed into Law on Dec. 19, 2007. Title IV
(“Energy Savings in Building and Industry”), Subtitle C (“High Performance Federal Buildings”) Sec. 438
(“Storm Water Runoff Requirements for Federal Development Projects”) requires that: “The sponsor of
any development or redevelopment project involving a Federal facility with a footprint that exceeds
5,000 square feet shall use site planning, design, construction, and maintenance strategies for the
property to maintain or restore, to the maximum extent technically feasible, the predevelopment
hydrology of the property with regard to the temperature, rate, volume, and duration of flow.” This new
provision requires much more attention to controlling runoff volume, in addition to other hydrologic
features. Current proposed state regulations require runoff volume restrictions so that postdevelopment runoff volumes meet pre-development runoff volumes for the 2-year rainfall (about 4
inches for the central Alabama area).
Our past research has examined regional soils and how they may affect infiltration capacity:
21
Loss of infiltration capacity due to soil disturbance and compaction during construction.
We have also researched groundwater contamination potential for stormwater infiltration. Potential
groundwater problems are affected by a stormwater pollutant’s abundance in the stormwater, its
mobility through the unsaturated zone above the groundwater, and the treatment received before
infiltration. Basically, with surface infiltration with minimal pretreatment (grass swales or roof
disconnections), mobility and abundance are most critical. With surface infiltration with sedimentation
pretreatment (treatment train: sedimentation then media filtration), mobility, abundance, and
treatability are all important. With subsurface injection with minimal pretreatment (porous pavement in
parking lot or dry well), only abundance affects groundwater contamination potential. We have found
that infiltration devices should not be used in most industrial areas without adequate pretreatment.
Runoff from critical source areas (mostly in commercial areas) need to receive adequate pretreatment
prior to infiltration. However, runoff from residential areas (the largest component of urban runoff in
most cities) is generally the least polluted and should be considered for infiltration.
Considerations for the use of porous pavement in Central Alabama:
• Soils having at least 0.1 in/hr infiltration rates can totally remove the runoff from porous
pavement areas, assuming about 1 ft coarse rock storage layer. Porous pavement areas can
effectively contribute zero runoff, if well maintained.
• However, slow infiltrating soils can result in slow drainage times of several days. Soils having
infiltration rates of at least 0.5 in/hr can drain the pavement structure and storage area within a
day, a generally accepted goal.
• These porous pavements can totally reduce the runoff during the intense 2-year rains.
• Good design and construction practice is necessary to prolong the life of the porous pavements,
including restricting runon, prohibiting dirt and debris tracking, and suitable intensive cleaning.
Considerations for the use of green roofs in Central Alabama:
• Green roofs can contribute to energy savings in operation of a building, can prolong the life of
the roof structure, and can reduce the amount of roof runoff.
22
•
•
They can be costly. However, they may be one of the few options for stormwater volume
control in ultra urban areas where ground–level options are not available.
Irrigation of the plants is likely necessary to prevent wilting and death during dry periods.
Reduction in Annual Roof Runoff (%)
80
70
60
50
40
30
20
10
0
0
20
40
60
80
100
Green Roof as a Percentage of Total Roof Area
Annual roof runoff reductions for local green roofs.
•
•
Vegetated green roofs can reduce up to about 70% of the annual roof runoff during typical
conditions, if the complete roof is planted.
The plants would likely wilt and die as the evapotranspiration (ET) drives the substrate to the
plants’ wilting point during the late summer, early fall period, requiring substantial irrigation.
Considerations for the use of rain gardens for controlling roof and paved area runoff in Central Alabama:
• Simple rain gardens with extensive excavations or underdrains can be used near buildings for
the control of roof runoff, or can be placed in or around the edges of parking areas for the
control of runoff from parking areas.
• Rain gardens provide greater groundwater contamination protection compared to porous
pavements as the engineered soil fill material should contain significant organic material that
hinders migration of many stormwater pollutants. This material also provides much better
control of fine sediment found in the stormwater.
• Rain gardens can be sized to control large fractions of the runoff, but maintenance to prevent
clogging and to remove contaminated soils is also necessary.
23
Reduction in Annual Impervious Area Runoff (%)
100
clay (0.02 in/hr)
10
silt loam (0.3 in/hr)
sandy loam (1 in/hr)
1
0.1
1
10
100
Rain Garden Size (% of drainage area)
Annual runoff reductions from paved areas or roofs for different sized rain gardens and soils.
•
•
•
•
•
Local rain gardens should be located in areas having soil infiltration rates of at least 0.3 in/hr.
Lower rates result in very large and much less effective rain gardens, and the likely clay content
of the soil likely will result in premature clogging.
Rain gardens should be from 5 to 10 percent of the drainage area to provide significant runoff
reductions (75+%).
Rain gardens of this size will result in about 40 to 60% reductions in runoff volume from the
large 4 inch rain. Rain gardens would need to be about 20% of the drainage area in order to
approach complete control of these large rains.
Roof runoff contains relatively little particulate matter and rain gardens at least 1% of the roof
area are not likely to clog (estimated 20 to 50 years).
Paved area runoff contains a much greater amount of particulate matter and would need to be
at least 10% of the paved area to have an extended life (>10 years).
Newly published federal construction site and stormwater regulations will require much more careful
site planning. Runoff volume controls during large events will require extensive use of infiltration
practices. The sizes of practices for the same land use is not very sensitive to soil conditions (less runoff
increases compared to pre-development conditions with poorer soils and therefore lower volume
reduction goals). However, use of infiltration controls in poor soils is not a very robust/sustainable
practice, and needs to be done with caution and over-sizing.
24
7. National Stormwater Quality Database, US EPA, 2001 – 2011
8. Detection and Corrections of Inappropriate Discharges to Stormwater
Drainage Systems, US EPA, 2001 – 2008
9. Relationships Between the Variability of Stormwater Characteristics and
Development Characteristics
Urban land uses and their associated impervious cover increase the quantity and worsen the quality of
stormwater runoff seriously impairing receiving waters. However, there is substantial variability in the
measured impervious covers, even within single land use areas. This research is investigating this
variability in relationship to the variability measured in stormwater quality. In order to determine how
land development variability affects the quantity and quality of runoff, different land surfaces (roofs,
streets, landscaped areas, parking lots, etc.) for different land uses (residential, commercial, industrial,
institutional, etc.) can be directly measured. This research examined 125 neighborhoods located in the
Little Shades Creek watershed (Jefferson County, near Birmingham, AL) and 40 neighborhoods located in
five highly urbanized drainage areas situated in Jefferson County, AL (in and near city of Birmingham),
along with stormwater quality data from the local stormwater monitoring program. A locally calibrated
version of the Source Loading and Management Model (WinSLAMM) was also used to calculate the
runoff quantity and quality for six highly urbanized drainage areas and to examine the performance of
different combinations of stormwater control devices. The research is determining the most suitable
methods for stormwater control based on variability in land uses, land development, and rain
characteristics.
25
Average source covers for high density residential areas.
Variabilities in measured directly connected impervious cover by land use.
For small rain depths, almost all the runoff and pollutants originate from directly connected impervious
areas, as disconnected areas have most of their flows infiltrated. For larger storms, both directly
connected and disconnected impervious areas contribute runoff to the stormwater drainage system. In
many cases, pervious areas are not hydrological active until the rain depths are relatively large and are
not significant runoff contributors until the rainfall exceeds about 25 mm for many land uses and soil
conditions. However compacted soils can greatly increase the flow contributions from pervious areas
during smaller rains. Urbanization radically transforms natural watershed conditions and introduces
impervious surfaces into the previously natural landscape. Total impervious areas are mostly composed
of rooftop and transportation related components that can be either directly connected or disconnected
to the drainage system. The impervious areas that are directly connected to the storm drainage system
are the greatest contributor of runoff and stormwater pollutant mass discharges under most conditions.
10. Heavy Metal Contamination of Soils in Treated Wood Burn Areas
This research examined the contamination of soils in areas where building debris were burnt in fires as a
trash disposal practice. The presence of treated wood in the fires greatly contaminated the soils with
heavy metals. This research examined the metal species that were leached from the soil. Arsenic,
chromium, and copper species leached from the ash of burned wood which has been treated with
chromated copper arsenate preservative were the major focus of this investigation. The research
encompasses a study of the composition and reactivity of soils, wood ash, and the sorption mechanisms
which immobilize and precipitate metal species. In particular, the research has shown positive results
regarding the feasibility of reducing the mobility of metal species by the addition of agricultural soil
amendments that will increase the natural attenuation ability of soils. Additional investigations involve
26
the testing of enhanced agricultural amendments that will have the ability to further increase the
natural attenuation of soils and therefore reduce the mobility of rainwater‐leached metal species from
these areas.
Column leaching test full-factorial experimental setup for examining metal migration from
contaminated soils at burn sites.
The use of agricultural gypsum retarding leaching of arsenic from contaminated soils.
27
Of the mixtures studied, the CaSO4 (gypsum) amendment acting alone was found to be the most
effective amendment for the overall retardation of Cr and As mobility. The CaSO4/AgLime combination
was a close second in As and Cr reduction. CaSO4 as a reactive soil amendment for the treatment of soils
containing Cr and As metals results in significant rates of reduction of metals mobility, approaching 80%
compared to unamended soil/CCA-ash mixtures over a simulated one-year leaching period. An
optimization study revealed that a ratio of 3:1 of CaSO4 to metals mass was most effective in reducing
the mobility of Cr and As metals. Use of a higher ratio would serve as a source for Ca+2 ions and should
guarantee long-term stabilization while maintaining the pH in the 7.3-8.0 range.
11. Stormwater Quality Modeling
12. Compaction of Urban Soils
28