September 2005
05/21/WQPC-WWF
EPA/600/R-05/113
Environmental Technology
Verification Report
Stormwater Source Area Treatment
Device
BaySaver Technologies, Inc.
Bay Saver Separation System, Model 10K
Prepared by
NSF International
Under a Cooperative Agreement with
4>EPA U.S. Environmental Protection Agency
ET V ETV ET
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Environmental Technology Verification Report
Stormwater Source Area Treatment Device
BaySaver Technologies, Inc.
Bay Saver Separation System, Model 10K
Prepared by:
NSF International
Ann Arbor, Michigan 48105
Under a cooperative agreement with the U.S. Environmental Protection Agency
Raymond Frederick, Project Officer
ETV Water Quality Protection Center
National Risk Management Research Laboratory
Water Supply and Water Resources Division
U.S. Environmental Protection Agency
Edison, New Jersey
September 2005
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Notice
The U.S. Environmental Protection Agency (EPA) through its Office of Research and
Development has financially supported and collaborated with NSF International (NSF) under a
Cooperative Agreement. The Water Quality Protection Center (WQPC), operating under the
Environmental Technology Verification (ETV) Program, supported this verification effort. This
document has been peer reviewed and reviewed by NSF and EPA and recommended for public
release. Mention of trade names or commercial products does not constitute endorsement or
recommendation by the EPA for use or certification by NSF.
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Foreword
The following is the final report on an Environmental Technology Verification (ETV) test
performed for NSF International (NSF) and the United States Environmental Protection Agency
(EPA). The verification test for the BaySaver Technologies, Inc. BaySaver Separation System,
Model 10K was conducted at a testing site in Griffin, Georgia, maintained by the City of Griffin
Public Works and Stormwater Department.
The EPA is charged by Congress with protecting the Nation's land, air, and water resources.
Under a mandate of national environmental laws, the Agency strives to formulate and implement
actions leading to a compatible balance between human activities and the ability of natural
systems to support and nurture life. To meet this mandate, EPA's research program is providing
data and technical support for solving environmental problems today and building a science
knowledge base necessary to manage our ecological resources wisely, understand how pollutants
affect our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for
investigation of technological and management approaches for preventing and reducing risks
from pollution that threaten human health and the environment. The focus of the Laboratory's
research program is on methods and their cost-effectiveness for prevention and control of
pollution to air, land, water, and subsurface resources; protection of water quality in public water
systems; remediation of contaminated sites, sediments and ground water; prevention and control
of indoor air pollution; and restoration of ecosystems. NRMRL collaborates with both public and
private sector partners to foster technologies that reduce the cost of compliance and to anticipate
emerging problems. NRMRL's research provides solutions to environmental problems by:
developing and promoting technologies that protect and improve the environment; advancing
scientific and engineering information to support regulatory and policy decisions; and providing
the technical support and information transfer to ensure implementation of environmental
regulations and strategies at the national, state, and community levels.
This publication has been produced as part of the Laboratory's strategic long-term research plan.
It is published and made available by EPA's Office of Research and Development to assist the
user community and to link researchers with their clients.
11
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Contents
Notice i
Foreword ii
Contents iii
Figures iv
Tables iv
Abbreviations and Acronyms v
Chapter 1 Introduction 1
1.1 ETV Purpose and Program Operation 1
1.2 Testing Participants and Responsibilities 1
1.2.1 U.S. Environmental Protection Agency 2
1.2.2 Verification Organization 2
1.2.3 Testing Organization 3
1.2.4 Analytical Laboratories 4
1.2.5 Vendor 4
1.2.6 Verification Testing Site 5
Chapter 2 Technology Description 6
2.1 Treatment System Description 6
2.2 Product Specifications 7
2.3 Operation and Maintenance 7
2.4 Technology Application and Limitations 8
2.5 Performance Claim 8
Chapters Test Site Description 9
3.1 Location and Land Use 9
3.2 Contaminant Sources and Site Maintenance 9
3.3 Stormwater Conveyance System and Receiving Water 11
3.4 Rainfall and Peak Flow Calculations 11
3.5 Bay Saver Installation 13
Chapter 4 Sampling Procedures and Analytical Methods 14
4.1 Sampling Locations 14
4.1.1 Influent 14
4.1.2 Effluent 14
4.1.3 Rain Gauge 14
4.2 Monitoring Equipment 14
4.3 Constituents Analyzed 15
4.4 Sampling Schedule 15
4.5 Field Procedures for Sample Handling and Preservation 16
Chapters Monitoring Results and Discussion 17
5.1 Storm Event Data 17
5.1.1 Flow Data Evaluation 17
5.1.2 Sample Aliquot Distribution 20
5.2 Monitoring Results: Performance Parameters 21
5.2.1 Concentration Efficiency Ratio 21
5.2.2 Sum of Loads 25
5.3 Particle Size Distribution 30
5.4 TCLP Analysis 31
in
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Chapter 6 QA/QC Results and Summary 32
6.1 Laboratory/Analytical Data QA/QC 32
6.1.1 Bias (Field Blanks) 32
6.1.2 Replicates (Precision) 33
6.1.3 Accuracy 35
6.1.4 Representativeness 36
6.1.5 Completeness 37
Chapter 7 Operations and Maintenance Activities 38
7.1 System Operation and Maintenance 38
Chapter 8 Vendor-Supplied Information 39
8.1 TSS and SSC Data 39
8.2 Sampling Procedure 40
8.3 Conclusions 40
Chapter 9 References 41
Appendices 42
A BaySaver Design and O&M Guidelines 42
B Verification Test Plan 42
C Event Hydrographs and Rain Distribution 42
D Analytical Data Reports with QC 42
Figures
Figure 2-1. Schematic of the BaySaver 6
Figure 3-1. As-built drawing for the BaySaver installation 10
Figure 3-2. Drainage basin map for the BaySaver installation 11
Tables
Table 4-1. Constituent List for Water Quality Monitoring 15
Table 5-1. Summary of Events Monitored for Verification Testing 18
Table 5-2. Peak Discharge Rate and Runoff Volume Summary 19
Table 5-3. Monitoring Results and Efficiency Ratios for Sediment Parameters 22
Table 5-4. Monitoring Results and Efficiency Ratios for Nutrients 23
Table 5-5. Monitoring Results and Efficiency Ratios for Metals 24
Table 5-6. Sediment Sum of Loads Efficiencies Calculated Using Various Flow Volumes 25
Table 5-7. Sediment Sum of Loads Results 27
Table 5-8. Nutrients Sum of Loads Results 28
Table 5-9. Metals Sum of Loads Results 29
Table 5-10. Particle Size Distribution Analysis Results 30
Table 5-11. TCLP Results for Cleanout Solids 31
Table 6-1. Field Blank Analytical Data Summary 32
Table 6-2. Field Duplicate Sample Relative Percent Difference Data Summary 34
Table 6-3. Laboratory Duplicate Sample Relative Percent Difference Data Summary 35
Table 6-4. Laboratory MS/MSD Data Summary 35
Table 6-5. Laboratory Control Sample Data Summary 36
IV
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Abbreviations and Acronyms
AST
BMP
cfs
EMC
EPA
ETV
ft2
ft3
gal
gpm
hr
in.
kg
L
Ib
NRMRL
mg/L
mm
NSF
O&M
PBM
PCG
QA
QC
SOL
SOP
TCLP
TO
USGS
VO
WQPC
Analytical Services, Inc.
best management practice
Cubic feet per second
Event mean concentration
U.S. Environmental Protection Agency
Environmental Technology Verification
Square feet
Cubic feet
Gallon
Gallon per minute
Hour
Inch
Kilogram
Liters
Pound
National Risk Management Research Laboratory
Milligram per liter
millimeters
NSF International, formerly known as National Sanitation Foundation
Operations and maintenance
Practical Best Management, LLC
Paragon Consulting Group
Quality assurance
Quality control
Sum of the loads
Standard Operating Procedure
Toxicity Characteristic Leaching Procedure
Testing Organization (Paragon Consulting Group)
United States Geological Survey
Verification Organization (NSF)
Water Quality Protection Center
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Chapter 1
Introduction
1.1 ETV Purpose and Program Operation
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative or improved
environmental technologies through performance verification and dissemination of information.
The goal of the ETV program is to further environmental protection by substantially accelerating
the acceptance and use of improved and more cost-effective technologies. ETV seeks to achieve
this goal by providing high quality, peer reviewed data on technology performance to those
involved in the design, distribution, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; stakeholder
groups, which consist of buyers, vendor organizations, and permitters; and with the full
participation of individual technology developers. The program evaluates the performance of
innovative technologies by developing test plans that are responsive to the needs of stakeholders,
conducting field or laboratory (as appropriate) testing, collecting and analyzing data, and
preparing peer reviewed reports. All evaluations are conducted in accordance with rigorous
quality assurance protocols to ensure that data of known and adequate quality are generated and
that the results are defensible.
NSF International (NSF), in cooperation with the EPA, operates the Water Quality Protection
Center (WQPC). The WQPC evaluated the performance of the BaySaver Technologies, Inc.
Bay Saver Model 10K (BaySaver), a stormwater treatment device designed to remove sediments
and floating particles from wet weather runoff.
It is important to note that verification of the equipment does not mean that the equipment is
"certified" by NSF or "accepted" by EPA. Rather, it recognizes that the performance of the
equipment has been determined and verified by these organizations for those conditions tested by
the Testing Organization (TO).
1.2 Testing Participants and Responsibilities
The ETV testing of the BaySaver was a cooperative effort among the following participants:
U.S. Environmental Protection Agency
NSF International
Paragon Consulting Group, Inc. (PCG)
Analytical Services, Inc. (ASI)
United States Geological Survey (USGS) Sediment Laboratory
BaySaver Technologies, Inc. (BaySaver)
The following is a brief description of each ETV participant and their roles and responsibilities.
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7.2.7 U.S. Environmental Protection Agency
The EPA Office of Research and Development, through the Urban Watershed Management
Branch, Water Supply and Water Resources Division, National Risk Management Research
Laboratory (NRMRL), provides administrative, technical, and quality assurance guidance and
oversight on all ETV WQPC activities. In addition, EPA provides financial support for operation
of the Center and partial support for the cost of testing for this verification. EPA's
responsibilities include:
Review and approval of the test plan;
Review and approval of verification report; and
Post verification report on the EPA website.
The key EPA contact for this program is:
Mr. Ray Frederick, ETV WQPC Project Officer
(732) 321-6627 email: frederick.ray@epa.gov
U.S. EPA, NRMRL
Urban Watershed Management Branch
2890 Woodbridge Avenue (MS-104)
Edison, New Jersey 08837-3679
7.2.2 Verification Organization
NSF is the verification organization (VO) administering the WQPC in partnership with EPA.
NSF is a not-for-profit testing and certification organization dedicated to public health, safety,
and protection of the environment. Founded in 1946 and located in Ann Arbor, Michigan, NSF
has been instrumental in development of consensus standards for the protection of public health
and the environment. NSF also provides testing and certification services to ensure that products
bearing the NSF name, logo and/or mark meet those standards.
NSF personnel provided technical oversight of the verification process. NSF provided review of
the test plan and was responsible for the preparation of the verification report. NSF contracted
with Scherger Associates to provide technical advice and to assist with preparation of the
verification report. NSF's responsibilities as the VO include:
Review and comment on the test plan;
Review quality systems of all parties involved with the TO, and qualify the TO;
Oversee TO activities related to the technology evaluation and associated laboratory testing;
Conduct an on-site audit of test procedures;
Provide quality assurance/quality control (QA/QC) review and support for the TO;
Prepare the verification report; and,
Coordinate with EPA to approve the verification report.
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Key contacts at NSF are:
Mr. Thomas Stevens, P.E., Program Manager
(734) 769-5347 email: stevenst@nsf.org
Mr. Patrick Davison, Project Coordinator
(734)913-5719 email: davison@nsf.org
NSF International
789 North Dixboro Road
Ann Arbor, Michigan 48105
(734) 769-8010
Mr. Dale A. Scherger, P.E., Technical Consultant
(734)213-8150 email: daleres@aol.com
Scherger Associates
3017 Rumsey Drive
Ann Arbor, Michigan 48105
1.2.3 Testing Organization
The TO for the verification testing was Paragon Consulting Group, Inc. (PCG) of Griffin,
Georgia. The TO was responsible for ensuring that the testing location and conditions allowed
for the verification testing to meet its stated objectives. The TO prepared the test plan, oversaw
the testing, and managed the data generated by the testing. TO employees set test conditions, and
measured and recorded data during the testing. The TO's Project Manager provided project
oversight.
PCG had primary responsibility for all verification testing, including:
Coordinate all testing and observations of the BaySaverin accordance with the test plan;
Contract with the analytical laboratory, contractors and any other subcontractors
necessary for implementation of the test plan;
Provide needed logistical support to subcontractors, as well as establishing a
communication network, and scheduling and coordinating the activities for the
verification testing; and,
Manage data generated during the verification testing.
The key contact for the TO is:
Ms. Courtney Nolan, P.E., Project Manager
(770) 412-7700 email: cnolan@pcgeng.com
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Paragon Consulting Group
118 North Expressway
Griffin, Georgia 30223
1.2.4 Analytical Laboratories
Analytical Services, Inc. (AST), located in Norcross, Georgia, analyzed the samples collected
during the verification test.
The key AST contact is:
Ms. Christin Ford
(770) 734-4200 email: cford@ASI.com
Analytical Services, Inc.
110 Technology Parkway
Norcross, Georgia 30092
USGS Kentucky District Sediment Laboratory analyzed the suspended sediment concentration
(SSC) samples.
The key USGS laboratory contact is:
Ms. Elizabeth A. Shreve, Laboratory Chief
(502)493-1916 email: eashreve@usgs.gov
United States Geological Survey, Water Resources Division
Northeastern Region, Kentucky District Sediment Laboratory
9818 Bluegrass Parkway
Louisville, Kentucky 40299
7.2.5 Vendor
BaySaver Technologies, Inc. of Mount Airy, Maryland, is the vendor of the BaySaver, and was
responsible for supplying a field-ready system. Vendor responsibilities include:
Provide the technology and ancillary equipment required for the verification testing;
Provide technical support during the installation and operation of the technology, including
the designation of a representative to ensure the technology is functioning as intended;
Provide descriptive details about the capabilities and intended function of the technology;
Review and approve the test plan; and
Review and comment on the draft verification report.
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The key contact for Bay Saver is:
Mr. Austin Meyermann, Director of Operations
(301) 829-6470 email: amevermann@baysaver.com
BaySaver Technologies, Inc.
1302 Rising Ridge Road
Mount Airy, Maryland 21771
1.2.6 Verification Testing Site
The BaySaver was located within right-of-way on the west side of Fifth Street in Griffin,
Georgia. A private contractor, Site Engineering, Inc, installed the system.
The key contact for City of Griffin Public Works and Stormwater Department is:
Mr. Brant Keller Ph.D., Director
(770)229-6424 email: bkeller@citvofgriffm.com
Public Works and Stormwater Department
City of Griffin
134 North Hill Street
Griffin, Georgia 30224
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Chapter 2
Technology Description
The following technology description was supplied by the vendor and does not represent verified
information.
2.1 Treatment System Description
The BaySaver is a device that removes sediment and floatable particles from stormwater. The
BaySaver is comprised of two pre-cast concrete manholes and a high-density polyethylene
BaySaver Separator Unit. The primary manhole is set in-line with the storm drainpipe, and the
storage manhole is offset to either side. The two manholes, which must be watertight, provide the
retention time and storage capacity necessary to remove the target pollutants from the influent
water. The BaySaver acts as a flow control device, diverting the influent water to the flow path
that will result in the most efficient pollutant removal. A schematic of the BaySaver is in
Figure 2-1.
Figure 2-1. Schematic of the BaySaver.
The primary manhole removes and retains coarse sediments from the influent water in an eight-
foot deep sump. A portion of the influent flow is skimmed from the surface of the primary
manhole by the BaySaver and conveyed into the storage manhole. This water enters and exits the
off-line storage manhole at an elevation below the water surface and above the floor of the
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structure, allowing both flotation and sedimentation to occur. The fine sediments and floatables
entrained in this water are retained in the storage manhole.
The BaySaver limits the flow through the storage manhole by allowing excess water to pass
directly from the primary manhole to the outfall. During higher-intensity storms (usually
two-year events), the BaySaver draws water from the center of the primary manhole,
approximately four feet below the water surface, and discharges it to the outfall. At the same
time, it continues to skim the surface water and treat it through the storage manhole. Extremely
high flows are conveyed by the separator unit directly to the outfall, and bypass the storage
manhole completely. More detailed information about the operation of the BaySaver, as well as
isometric drawings of the system, can be found in the BaySaver Separation System Technical
and Design Manual (Appendix A).
The storage manhole stores fine sediments, oils, and floatables off-line, and the internal bypass
minimizes the risk of re-suspending and discharging these contaminants. Additionally, the
system is designed to minimize the volume of water that must be removed during routine
maintenance, which results in lower disposal fees.
2.2 Product Specifications
BaySaver Model 10K:
Housing construction/dimensions - two 10-ft diameter concrete manholes
Maximum treatment capacity - 21.8 cfs
Peak design capacity - 100 cfs
Sediment storage -11.6 yd3
Sediment chamber size - 10 ft diameter x 8 ft deep
Floatables storage - 1,740 gal
2.3 Operation and Maintenance
The BaySaver must be maintained for continued effectiveness. Maintenance is performed using a
vacuum truck or similar equipment when sediment levels reach two feet in either manhole.
Access to the contaminant storage is available through 30-in. manhole covers in each structure,
and the entire floor of each structure should be visible from the surface. Maintenance can be
performed and inspected without confined space entry.
The maintenance procedure typically takes from three to five hours. BaySaver recommends
removing all water, debris, oils, and sediment from the storage manhole using a vacuum truck or
other equipment. Then, using a high-pressure hose, the storage manhole should be cleaned and
the cleaning water removed using the vacuum truck. The two structures should then be filled
with clean water.
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2.4 Technology Application and Limitations
The BaySaver is flexible in terms of the flow it can treat. Baysaver offers units designed with a
maximum treatment flow ranging from 1.1 to 21.8 cfs, or a peak design capacity ranging from
8.5 to 100 cfs. BaySaver also offers custom-designed units based on site-specific conditions.
The BaySaver can be used to treat stormwater runoff in a wide variety of sites throughout the
United States. For jurisdictional authorities, the system offers solids and debris removal and
improved water quality. The BaySaver may be used for development, roadways, and specialized
applications. Typical development applications include parking lots, commercial, and industrial
sites, and high-density and single-family housing. Typical development applications also include
maintenance, transportation and port facilities.
The BaySaver works primarily as a settling device. The large capacity of the BaySaver manholes
decreases the velocity of the entering stormwater, promoting solids to settle and floating debris
and hydrocarbons to float to the water surface.
2.5 Performance Claim
According to the vendor, the BaySaver will provide a total suspended solids concentration net
removal efficiency ranging between 60 to 80%, and will remove a significant portion of the free
oils entering the system.
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Chapter 3
Test Site Description
3.1 Location and Land Use
The BaySaver is located within the City of Griffin right-of-way, along Third Street, just north of
the southwest corner of the intersection of Third Street and Taylor Street at 33° 14' 49.4880"
latitude and 84° 15' 26.4960" longitude. These coordinates are based on Arcview's Global
Information System (GIS) utilizing state plane coordinates.
Figure 3-1 is an as-built drawing of the BaySaver and adjacent features, while Figure 3-2
identifies the drainage basin, the location of the unit, and the surface contours of the basin. The
drainage basin consists of approximately 10 acres. An estimated 75% of the basin is impervious
and includes about 100 linear feet of storm sewer along with approximately six storm inlets. No
detention areas or open ditches are located within the drainage basin. No open ditches are located
upstream of the BaySaver installation location.
The majority of the drainage basin consists of paved roadways, parking areas and buildings. A
barbeque restaurant, school facilities, a bank, an automotive service business, and residences are
located in the drainage basin. Small portions of the drainage basin are either landscaped sections
or lawns. Moderate to heavy traffic volume runs along Taylor Street, but no major storage or use
of hazardous materials or chemicals exists in the area. None of the stormwater runoff from the
basin was pretreated prior to entering the BaySaver.
The nearest receiving water is Grape Creek, which is located approximately two-thirds of a mile
east of the BaySaver. All water, either treated or bypass, flows via pipe flow in an easterly
direction approximately 1,100 feet through storm pipe and ultimately flows into Grape Creek.
Griffin has many local ordinances to aid in stormwater management improvement and
implement pollution control measures. Such ordinances include establishment of the stormwater
utility, soil erosion and sediment control, buffer width, and land disturbance requirements.
Copies of the existing ordinances are included in Attachment E of the test plan.
3.2 Contaminant Sources and Site Maintenance
The main pollutant sources within the basin are created by vehicular traffic, typical urban
commercial land use, and atmospheric deposition. Trash and debris accumulate on the surface
and enter the stormwater system through large openings in the street inlets, sized to
accommodate the large storm flows that can occur in this part of Georgia. The storm sewer catch
basins do not have sumps. There are no other stormwater best management practices (BMPs)
within the drainage area.
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TOP 922.03
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Figure 3-1. As-built drawing for the BaySaver installation.
10
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ICO Q ltd 310 '»i I'.i'l
Figure 3-2. Drainage basin map for the BaySaver installation.
No planned or on-going maintenance activities are in place for the area of the installation, such
as street sweeping or catch basin cleaning. Because Taylor Street is a State Highway, the
Georgia Department of Transportation is responsible for maintenance activities along the road.
According to Griffin Public Works Department personnel, if such activities were performed,
Griffin would either be involved with the actions, or at least informed that the activities are to
take place. Such maintenance activities are typically only performed during emergencies.
3.3 Stormwater Conveyance System and Receiving Water
As previously discussed, the nearest receiving water is Grape Creek, which is located
approximately two-thirds of a mile east of the BaySaver unit. All water, either treated or bypass,
flows via pipe flow in an easterly direction approximately 1,100 ft through storm pipe and
ultimately flows into Grape Creek.
3.4 Rainfall and Peak Flow Calculations
The rainfall amounts for the 1,2, 10, and 25-yr storms for the drainage area are presented in
Table 3-1. Table 3-2 presents the intensities in inches per hour calculated for the given rainfall
depths. These data were utilized to generate the peak flows shown in Table 3-3. Table 3-4
presents the peak flow calculated using the time of concentration for the drainage basin.
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Griffin requires that all storm drain systems be designed to accommodate the 25-yr storm. A
6.07-min time of concentration was determined for the basin, generating a peak runoff of
82.47 cfs for the 25-yr storm event. The rational method was used to calculate the peak flows for
the device, since the drainage basin is just over ten acres. The rationale for these calculations was
discussed in the test plan.
Table 3-1. Rainfall Depth (in.)
Duration 1-yr 2-yr 10-yr 25-yr
6.07 min
30 min
Ihr
2hr
12 hr
0.31
0.53
0.72
1.00
1.80
0.42
1.19
1.61
2.00
3.12
0.65
1.81
2.40
2.98
4.44
0.76
2.10
2.77
3.46
5.16
Source: NOAA,2000
Table 3-2. Intensities (in./hr)
Duration 1-yr 2-yr 10-yr 25-yr
30 min
Ihr
2hr
12 hr
24 hr
1.05
0.72
0.50
0.11
0.07
Table 3-3. Peak Flow Calculations
Duration
30 min
Ihr
2hr
12 hr
24 hr
1-yr
9.56
7.10
4.55
1.00
0.64
Table 3-4. Peak Flow Calculations
Duration
6.07 min
1-yr
33.68
2.38
1.61
1.00
0.26
0.14
(cfs)
2-yr
21.66
14.65
9.10
2.37
1.27
(cfs) Using
2-yr
45.78
3.61
2.40
1.49
0.37
0.20
10-yr
32.86
21.85
13.56
3.37
1.82
4.20
2.77
1.73
0.43
0.23
25-yr
38.23
25.21
15.75
3.91
2.09
Time of Concentration
10-yr
70.72
25-yr
82.47
12
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3.5 BaySaver Installation
The construction contractor utilized to complete the construction work associated with the
installation of the Bay Saver device was determined by a competitive bidding process, and was
monitored by the City of Griffin as part of the TEA-21 project. The bid opening took place on
March 11, 2002. Site Engineering, Inc. of Atlanta, Georgia the selected contractor. The
installation of the BaySaver, Inc. device was initiated in April, 2002 and completed in July 2002.
No major issues were noted during the installation process.
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Chapter 4
Sampling Procedures and Analytical Methods
Descriptions of the sampling locations and methods used during verification testing are
summarized in this section. The test plan presents the details on the approach used to verify the
BaySaver unit. This plan, Environmental Technology Verification Test Plan For Baysaver Inc.,
The BaySaver Separation System, TEA-21 Project Area, City of Griffin, Spalding County,
Georgia, NSF, June 2003, is presented in Appendix B with all attachments. An overview of the
key procedures used for this verification is presented below.
4.1 Sampling Locations
Two locations in the test site storm sewer system were selected as sampling and monitoring sites
to determine the treatment capability of the BaySaver.
4.1.1 Influent
This sampling and monitoring site was selected to characterize the untreated stormwater from the
entire basin. A velocity/stage meter and sampler suction tubing were located in the inlet pipe,
upstream from the BaySaver so that potential changes in flow characteristics caused by the
treatment device would not affect the velocity measurements.
4.1.2 Effluent
This sampling and monitoring site was selected to characterize the stormwater treated by the
BaySaver. A velocity/stage meter and sampler suction tubing, connected to the automated
sampling equipment, were located in the pipe downstream from the BaySaver. This location
measured all of the water discharged from the system including any water that bypassed the
storage manhole or the primary manhole.
4.1.3 Rain Gauge
A rain gauge was located at the effluent sampler location to monitor the depth of precipitation
from storm events. The data were used to characterize the events to determine if the requirements
for a qualified storm event had been achieved.
4.2 Monitoring Equipment
The specific equipment used for monitoring flow, sampling water quality, and measuring rainfall
for the upstream and downstream monitoring points is listed below:
Sampler: American Sigma 900MAX automatic sampler with DTU II data logger;
Sample Containers: Two 1.9-L glass bottles and six polyethylene bottles, or one four-
gallon polyethylene container;
Flow Monitors: American Sigma Area/Velocity Flow Monitors; and
Rain Gauge: American Sigma Tipping Bucket, Model 2149.
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4.3 Constituents Analyzed
The list of constituents analyzed in the stormwater samples is shown in Table 4-1.
Table 4-1. Constituent List for Water Quality Monitoring
Parameter
Total suspended solids (TSS)
Suspended sediment
concentration (SSC)
Total phosphorus
Total Kjeldahl nitrogen
(TKN)
Nitrate and nitrite nitrogen
Total zinc
Total lead
Total copper
Total cadmium
Sand-silt split
Reporting
Units
mg/L
mg/L
mg/L as P
mg/L as N
mg/L as N
Hg/L
Hg/L
Hg/L
Hg/L
NA
Method
Detection Limit
5
0.5
0.02
0.4
0.02
4
5
4
0.5
NA
Method1
EPA 160.2
ASTMD3977-97
SM 4500-P B,E
EPA 35 1.3
EPA 9056
EPA 200.7
EPA 200.7
EPA 200.7
EPA 7131
Fishman et al
1 EPA: EPA Methods and Guidance for the Analysis of Water procedures; ASTM: American Society
of Testing and Materials procedures; SM: Standard Methods for the Examination of Water and
Wastewater procedures; Fishman et al.: Approved Inorganic and Organic Methods for the
Analysis of Water and Fluvial Sediment procedures; NA: Not applicable.
4.4 Sampling Schedule
The monitoring equipment was installed in August 2002. From September 2002 through March
2003, several trial events were monitored and the equipment tested and calibrated. Verification
testing began in March 2003, and ended in November 2004. As defined in the test plan,
"qualified" storm events met the following requirements:
The total rainfall depth for the event, measured at the site rain gauge, was 0.2 in. (5 mm) or
greater.
Flow through the treatment device was successfully measured and recorded over the duration
of the runoff period.
A flow-proportional composite sample was successfully collected for both the influent and
effluent over the duration of the runoff event.
15
-------
Each composite sample collected was comprised of a minimum of five aliquots, including at
least two aliquots on the rising limb of the runoff hydrograph, at least one aliquot near the
peak, and at least two aliquots on the falling limb.
There was a minimum of six hours between qualified sampling events.
4.5 Field Procedures for Sample Handling and Preservation
Water samples were collected with Sigma automatic samplers programmed to collect aliquots
during each sample cycle. A peristaltic pump on the sampler pumped water from the sampling
location through Teflon-lined sample tubing to the pump head where water passed through
silicone tubing and into the sample collection bottles. Samples were removed from the sampler,
split and capped after the event by PCG personnel. Samples were preserved per method
requirements and analyzed within the holding times allowed by the methods. Particle size and
SSC samples were shipped to the USGS sediment laboratory, while all other samples were
shipped to AST for analysis. Custody was maintained according to the laboratory's sample
handling procedures. To establish the necessary documentation to trace sample possession from
the time of collection, field forms and lab forms (see Attachment G of the test plan) were
completed and accompanied each sample.
The test plan included sampling and analysis for oil and grease (total petroleum hydrocarbons
and polynuclear aromatic hydrocarbons). For events sampled before December 2003, the
autosampling equipment was programmed to place the first two aliquots in the glass sample
containers, and to composite the subsequent aliquots in the polyethylene sample containers. In
December 2003, the TO, VO, vendor, and EPA agreed to discontinue oil and grease analyses
after all analytical results showed undetected hydrocarbon concentrations. When this change was
made, the TO changed to a single four-gallon polyethylene sample container.
16
-------
Chapter 5
Monitoring Results and Discussion
Precipitation and stormwater flow records were evaluated to verify that the storm events met the
qualified event requirements. The qualified event data is summarized in this chapter. The
monitoring results related to contaminant reduction are reported in two formats:
1. Efficiency ratio comparison, which evaluates the effectiveness of the system on an
event mean concentration (EMC) basis.
2. Sum of loads (SOL) comparison, which evaluates the effectiveness of the system on a
constituent mass (concentration times volume) basis.
5.1 Storm Event Data
Table 5-1 summarizes the storm data for the qualified events. Detailed information on each
storm's runoff hydrograph and the rain depth distribution over the event period are included in
Appendix C. The sample collection starting times for the inlet and outlet samples, as well as the
number of sample aliquots collected, varied from event to event. The samplers were activated
when the respective velocity meters sensed flow in the pipes and the depth reached 0.5 in. to
provide sufficient depth for sample collection.
5.1.1 Flow Data Evaluation
Table 5-2 summarizes the flow volumes and peak discharge rates for the inlet and outlet for each
of the qualified events. A sizable difference was observed between the inlet and outlet flow
during most storm events. Difficulties in gauging water depth and velocity in an open channel
can result in flow measurement discrepancies in stormwater studies. For this installation, the
open-channel flow was measured using area-velocity flow monitors, which measure water depth
and velocity and calculate flow based on the diameter of the pipe. The depth gauge measures the
pressure of the water and converts this to a depth. In spite of the TO's frequent inspections and
calibrations of the flow probes, the depth readings, and subsequent calculated flow, are prone to
error. The inlet and outlet pipes for the BaySaver unit in Griffin, Georgia are 42 in. in diameter.
For pipes this large, a relatively minor difference in depth readings can translate into a sizable
difference in flow.
The BaySaver does not have an external bypass mechanism, so the calculated inlet and outlet
event volumes should be the same, and a comparison of the calculated inlet and outlet volumes
can be used to ensure both flow monitors worked properly. The BaySaver manholes retain a
certain amount of water between events, but since this retained volume is constant between
events, the net runoff volume into the unit should equal the net runoff volume exiting the unit.
17
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Table 5-1. Summary of Events Monitored for Verification Testing
Event Start
No. Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Start
Time
19:45
0:55
15:50
14:50
17:05
15:05
23:55
11:35
18:25
22:40
19:25
11:25
15:35
18:50
1:50
End
Date
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/13/04
6/14/04
6/27/04
6/29/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Rainfall
End Amount
Time (in.)
22:35
3:40
21:20
21:15
20:20
16:55
6:30
21:55
22:00
0:35
22:40
16:35
17:20
22:20
14:15
0.32
0.48
0.67
0.46
0.52
1.16
0.97
0.43
0.79
0.51
1.13
0.71
0.29
0.36
1.16
Rainfall
Duration
(hnmin)
2:
2:
4:
6:
3:
1:
6:
10
3:
1:
3:
5:
1:
3:
12
50
45
30
25
15
50
35
:20
35
55
15
10
45
30
:25
Inlet Outlet
Inlet Peak Outlet Peak
Runoff Discharge Runoff Discharge
Volume Rate Volume Rate
(gal) (gpm) (gal) (gpm)
46,100
51,900
74,400
43,800
20,500
34,300
22,400
16,100
20,900
24,800
66,400
55,800
7,140
15,100
17,600
3,520
1,050
386
466
313
1,500
394
661
1,420
1,150
2,220
366
327
610
295
16,400
30,100
60,500
56,700
47,000
64,700
63,300
56,800
68,800
63,300
114,000
99,100
21,000
30,700
91,500
1,180
725
595
468
620
6,400
719
840
1,460
1,310
3,690
678
955
1,480
1,640
The test plan indicates that the sum of loads value be calculated by multiplying inlet analytical
concentrations with inlet flow measurements and outlet flow concentrations with outlet flow
measurements. Utilizing this method when flow measurements are unequal can result in the
differences in the recorded flow volumes having a large impact the SOL load reduction
efficiency calculation. To eliminate this possible bias, a standard practice for ETV reports is to
use either the inlet or outlet flow volumes in the SOL calculation. This approach is discussed
further later in this section.
The depth, velocity and flow data were evaluated to assess whether the differences were based
on an unusual trend or occurrence that would identify one set of data to be more reliable than the
other. Both flow monitors were calibrated regularly, and both appeared to function properly
during every qualified storm event.
Flow rate is very sensitive to depth in large diameter pipes, such as the 42-in. diameter inlet and
outlet pipes in this system. A small error in depth measurement can result in large errors in flow
rate and calculated runoff volume. In an equilibrium flow condition in this system, based on the
inlet and outlet pipe slopes (approximately 3.5% and 1.5%, respectively), the inlet would be
expected to have a slightly lower water level (approximately 0.2 to 0.4 in. at the depth and flow
range observed during the 2004 events) compared to the outlet.
18
-------
Table 5-2. Peak Discharge Rate and Runoff Volume Summary
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Peak Discharge Rate (gpm)
Inlet Outlet
3,520
1,050
386
466
313
1,500
394
661
1,420
1,150
2,220
366
327
610
295
1,180
725
595
468
620
6,400
719
840
1,460
1,310
3,690
678
955
1,480
1,640
Runoff Volume (gal)
Inlet Outlet
46,100
51,900
74,400
43,800
20,500
34,300
22,400
16,100
20,900
24,800
66,400
55,800
7,140
15,100
17,600
16,400
30,100
60,500
56,700
47,000
64,700
63,300
56,800
68,800
63,300
114,000
99,100
21,000
30,700
91,500
Runoff Coefficient
(dimensionless)1
Inlet Outlet
0.53
0.40
0.41
0.35
0.15
0.11
0.09
0.09
0.10
0.18
0.22
0.29
0.09
0.15
0.06
0.19
0.23
0.33
0.45
0.33
0.21
0.24
0.33
0.32
0.46
0.37
0.51
0.27
0.31
0.29
1. Runoff coefficient calculated using a drainage area of 435,600ft2 (10 acres).
There was no consistent trend during the 2003 events to explain the differences in volumes for
the 2003 data. However, for the 2004 events, the inlet water level reading tended to read
approximately one inch lower than the correlating outlet reading. Based on the standard Manning
formula, an inlet level reading one inch lower than the outlet pipe level would result in a
recorded inlet flow rate approximately 50 to 200 gpm lower than the equivalent outlet flow rate
in the range of inlet levels typically observed during the 2004 events. This difference appears to
be the primary reason for the differences in the inlet and outlet flows and runoff volumes.
In spite of identifying the likely source of the differences in the inlet and outlet flows and runoff
volumes, there were no specific trends observed in the data sets (inlet and outlet depths,
velocities and flows) to clearly identify either the inlet or outlet data as the preferred data.
A number of flow and drainage models have been developed to predict flow conditions within a
given drainage basin. A common means for determining the runoff for minor hydraulic structures
in urban areas is the rational formula, which estimates runoff as a function of rainfall depth, and
the drainage area size and imperviousness. While this formula provides only estimates of runoff
volume, given the sometimes large discrepancy between inlet and outlet volumes, the formula
can provide an indication of which recorded volume makes the most sense for the drainage basin
and recorded precipitation. The VO conducted an evaluation of the flow volumes based on the
rational formula by calculating runoff coefficients for the inlet and outlet volumes for each storm
event. The runoff coefficients shown in Figure 5-2 were calculated using the following equation:
19
-------
C-TA
where:
C = Runoff Coefficient (dimensionless)
Q = Total Flow Volume (ft3)
/ = Rainfall Depth (ft)
A = Drainage Basin Area (ft2)
Calculating the inlet and outlet runoff coefficient based on the recorded inlet and outlet flow
measurements and rainfall depth can give an indication as to which set of runoff data is more
reliable. Common runoff coefficients for single-family residential or light industrial areas,
similar to the BaySaver drainage area, range from 0.3 to 0.8 (Merritt, 1976). While the calculated
runoff coefficients at the test site are lower than the anticipated range, it is apparent that the inlet
coefficient values for the 2003 events and the outlet coefficient values for the 2004 values are
closer to the anticipated coefficient range. Therefore, the inlet flow volumes for the 2003 storm
events and the outlet flow volumes for the 2004 storm events were used in the SOL calculation.
The runoff volume issue is discussed further in Section 5.2.2
5.1.2 Sample Aliquot Distribution
The differences in flow measurements between inlet and outlet samples also impacted the
number and distribution of sample aliquots across the hydrograph. The protocol indicates a
minimum number of samples aliquots that need to be collected on the rising limb, peak, and
falling limb of the hydrograph.
During Event 8 (June 14, 2004), for example, the flow meters measured 16,100 gallons entering
the BaySaver and 56,800 gallons leaving the system. Each composite sample is comprised of
individual aliquots taken at regular intervals based on flow pacing. For Event 8, the inlet sample
is comprised of 30 aliquots, six (20% of the inlet volume) of which were taken on the rising limb
of the hydrograph (during the first 20 min of the storm). This sample is compared with an outlet
sample made up of 90 aliquots, seven of which were taken from the rising leg of the hydrograph,
representing less than eight percent of this sample by volume. Event 8 has two peaks. The inlet
sample is divided fairly evenly: of 30 aliquots, six are on the first rising limb, one at the first
peak, nine on the first falling limb, eight on the second rising limb, one at the second peak, and
five on the second falling limb. The outlet sample, though, is heavily weighted toward the first
falling leg and the second rising leg. A total of 48 of the 90 aliquots are taken from the falling
leg of the first peak, while 29 are taken from the rising leg of the second peak. No aliquots are
taken from the falling limb of the second peak. Similar circumstances arose during events 6
(May 18, 2004), 7 (June 12, 2004), and 11 (June 30, 2004).
The protocol does not specify that the number or distribution of sample aliquots for the inlet and
outlet match. Instead, the protocol specifies that a representative composite sample consist of
flow-proportional aliquots collected over certain intervals over the duration of the runoff event.
The TO tried to pace the rate of inlet and outlet sample collection to achieve a degree of
20
-------
equivalency between the sample aliquots, but during many cases, this was not achieved. The
composite samples were still considered representative for events where the number or
distribution of inlet and outlet sample aliquots differed so long as the protocol criteria were met.
5.2 Monitoring Results: Performance Parameters
5.2.1 Concentration Efficiency Ratio
The concentration efficiency ratio reflects the treatment capability of the device using the event
mean concentration (EMC) data obtained for each runoff event. The concentration efficiency
ratios are calculated by:
Efficiency ratio = 100 x (l-[EMCoutiet/EMCiniet]) (5-2)
The inlet and outlet sample concentrations and calculated efficiency ratios are summarized by
analytical parameter categories: sediments (TSS and SSC), total metals (cadmium copper, lead,
and zinc), and nutrients (total phosphorus, TKN, nitrates, and nitrites).
Sediments: The inlet and outlet sample concentrations and calculated efficiency ratios for
sediments are summarized in Table 5-3. The TSS inlet concentrations ranged from 11 to 260
mg/L, the outlet concentrations ranged from 12 to 110 mg/L, and the efficiency ratio ranged
from -620 to 94%. Events with large negative efficiency ratios had very low (less than 30 mg/L)
inlet TSS concentrations. The SSC inlet concentrations ranged 26 to 2,700 mg/L, the outlet
concentrations ranged from 21 to 230 mg/L, and the efficiency ratio ranged from -140 to 98%.
The inlet SSC concentrations for the first four events are dramatically higher than the inlet SSC
concentrations for the last eleven events. Between these events, the TO encountered frequent
difficulties with the inlet auto sampler becoming obstructed or plugged, or blowing fuses on the
auto sampler. On April 26, 2004, after the BaySaver inlet auto sampler failed to sample several
events, the TO reported that the intake port had created an obstruction in the pipe sufficient to
cause a two-inch deep accumulation of sediment around the intake port at the bottom of the pipe.
The TO had to modify the test apparatus location to compensate for the difficulties inherent in
stormwater sampling and particularly prevalent at this test site in order to successfully sample
storm events. The TO moved the intake port approximately ten inches to the side of the pipe
invert to prevent it from accumulating sediment. After this modification was made, the auto
sampler was able to successfully sample storm events without blowing fuses during storm
events. However, since the sample intake port was no longer at the bottom of the pipe, this
modification may have resulted in the collection of samples during 2004 events that did not
contain some of the heavier solids concentrations moving along the bottom of the pipe.
Conversely, a buildup of solids near the sample intake screen observed by the TO could have
resulted in a disproportionate amount of the heavier solids being collected in the samples during
the 2003 events. A review of the sediment analytical data shows that the inlet SSC
concentrations decreased significantly after this change was made. The inlet solids concentration
was lower than the corresponding outlet solids concentration in more than 60% of the 2004
events. This in turn yielded negative sediment removal efficiencies for most of the 2004 storm
events, as shown in Table 5-3. No significant sediment accumulation or modifications to the
21
-------
sampling setup was required on the outlet sampler, and the outlet sediment data remained fairly
steady throughout the verification period.
Table 5-3. Monitoring Results and Efficiency Ratios for Sediment Parameters
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Inlet
(mg/L)
190
11
30
18
26
40
46
38
18
22
26
25
18
260
56
TSS
Outlet
(mg/L)
12
79
16
30
26
54
63
47
42
32
28
24
38
110
33
Reduction
(%)
94
-620
47
-67
0
-35
-37
-24
-130
-45
-7.7
4.0
-110
57
41
Inlet
(mg/L)
2,700
710
830
1,100
48
68
54
33
26
44
42
30
41
180
94
ssc
Outlet
(mg/L)
230
56
21
26
57
81
74
55
62
110
35
27
44
61
46
Reduction
(%)
91
92
97
98
-19
-19
-37
-67
-140
-140
17
10
-7.3
65
51
Nutrients: The inlet and outlet sample concentrations and calculated efficiency ratios for
nutrients are summarized in Table 5-4. Total phosphorus inlet concentrations ranged from 0.07
to 0.47 mg/L (as P), and the EMC ranged from -38 to 85%. TKN inlet concentrations ranged
from 0.4 to 4.4 mg/L (as N), and the EMC ranged from -38 to 85%. Total nitrate inlet
concentrations ranged from 0.10 to 1.7 mg/L (as N), and the EMC ranged from -280 to 55%.
Total nitrite inlet and outlet concentrations were near or below method detection limits, such that
a minor difference in concentration could result in a very significant calculated percent removal
difference. This should be taken into consideration if using the EMC data to project the
Bay Saver's actual nitrite treatment capability.
Metals: The inlet and outlet sample concentrations and calculated efficiency ratios for metals are
summarized in Table 5-5. Total cadmium inlet and outlet concentrations were near or below the
method detection limits such that a minor difference in concentration could result in a very
significant calculated% removal difference. Total copper inlet concentrations ranged from 0.006
to 0.030 mg/L, and the EMC reductions ranged from -200 to 50%. Total lead inlet concentrations
ranged from 0.020 to 0.140 mg/L, and the EMC reductions ranged from -550 to 97%. Total zinc
inlet concentrations ranged from 0.06 to 0.19 mg/L, and the EMC reductions ranged from -170
to 43%. Many of the large negative EMC values occur when the inlet and outlet metals
concentrations are close to the method detection limits.
22
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Table 5-4. Monitoring Results and Efficiency Ratios for Nutrients
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
3/5iMet
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Total phosphorus (as P)
Outlet Reduction
(mg/L) (mg/L) (%)
0.70
0.07
0.13
0.21
0.13
0.47
0.25
0.17
0.08
0.08
0.25
0.19
0.16
0.13
0.18
0.15
0.09
0.11
0.12
0.17
0.22
0.21
0.18
0.11
0.07
0.25
0.20
0.17
0.02
0.11
79
-29
15
43
-31
53
16
-5.9
-38
13
0
-5.3
-6.3
85
39
TKN (as
Inlet Outlet
(mg/L) (mg/L)
4.4
0.5
0.8
2.6
1.3
1.9
1.8
0.5
0.4
1.3
1.0
1.2
2.1
1.0
1.5
1.3
0.9
0.7
1.4
1.7
1.1
1.3
0.6
0.9
1.0
0.8
2.6
1.4
0.8
0.9
N)
Reduction
70
-80
13
46
-31
42
28
-20
-130
23
20
-120
33
20
40
Total nitrate (as N) Total nitrite (as N)
Inlet Outlet Reduction Inlet Outlet Reduction
(mg/L) (mg/L) (%) (mg/L) (mg/L) (%)
0.10
0.46
NA
NA
0.46
0.51
0.81
0.27
1.5
0.36
0.18
0.22
0.41
0.30
1.7
0.10
0.62
NA
NA
0.33
0.32
0.44
0.33
1.2
1.4
0.06
0.21
0.81
0.23
0.75
0
-35
ND
ND
28
37
46
-22
18
-280
67
4.5
-98
23
55
<0.01
<0.01
NA
NA
0.02
0.02
0.04
0.02
<0.01
<0.01
<0.01
<0.01
0.03
0.02
0.02
<0.01
<0.01
NA
NA
0.02
0.02
0.02
0.02
<0.01
0.01
<0.01
<0.01
0.02
<0.01
<0.01
ND
ND
ND
ND
0
0
50
0
ND
ND
ND
ND
33
75
75
NA: Not analyzed due to expiration of hold time.
ND: Not determinable.
Values in boldface text represent results where one-half the method detection limit was substituted for values below detection limits to calculate EMC.
23
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Table 5-5. Monitoring Results and Efficiency Ratios for Metals
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Total cadmium Total copper
Inlet Outlet Reduction Inlet Outlet Reduction
(mg/L) (mg/L) (%) (mg/L) (mg/L) (%)
<0.01
<0.01
0.0007
0.0006
O.0005
0.002
0.001
O.0005
O.0005
0.0006
O.0005
O.0005
O.0005
<0.0005
<0.0005
<0.01
<0.01
<0.0005
<0.0005
0.001
0.0008
0.0009
<0.0005
<0.0005
0.0005
<0.0005
0.0005
<0.0005
<0.0005
<0.0005
ND
ND
57
50
ND
60
10
ND
ND
17
ND
ND
ND
ND
ND
<0.01
0.01
0.02
0.02
0.01
0.03
0.03
0.02
0.006
0.008
0.01
0.009
0.02
0.01
0.02
<0.01
0.03
0.01
0.02
0.02
0.04
0.03
0.02
0.013
0.01
0.01
0.009
0.02
0.01
0.02
ND
-200
50
0
-100
-33
0
0
-120
-25
0
0
0
0
0
Inlet
(mg/L)
0.03
0.02
0.06
0.05
0.02
0.12
0.14
0.06
0.03
0.06
0.02
0.02
0.06
0.02
0.10
Total lead
Outlet Reduction
(mg/L) (%)
<0.002
0.13
0.04
0.03
0.08
0.25
0.22
0.09
0.09
0.09
0.03
0.03
0.11
0.04
0.09
97
-550
33
40
-300
-110
-57
-50
-200
-50
-50
-50
-83
-100
10
Inlet
(mg/L)
0.08
0.14
0.14
0.16
0.11
0.19
0.38
0.14
0.06
0.09
0.06
0.08
0.14
0.08
0.17
Total zinc
Outlet Reduction
(mg/L) (%)
0.06
0.38
0.08
0.10
0.21
0.20
0.26
0.15
0.09
0.09
0.07
0.09
0.16
0.08
0.10
25
-170
43
38
-91
-5.3
32
-7.1
-50
0
-17
-13
-14
0
41
ND: Not determinable.
Values in boldface text represent results where one-half the method detection limit was substituted for values below detection limits to calculate EMC.
24
-------
5.2.2 Sum of Loads
The sum of loads (SOL) is the sum of the% load reduction efficiencies for all the events, and
provides a measure of the overall performance efficiency for the events sampled during the
monitoring period. The load reduction efficiency is calculated using the following equation:
Yo Load Reduction Efficiency = 100 x (1 - (A / B))
(5-3)
where:
A = Sum of Outlet Load = (Outlet EMCi)(Flow Volumei) +
(Outlet EMC2)(Flow Volume2) + (Outlet EMCn)(Flow Volumen)
B = Sum of Inlet Load = (Inlet EMCi)(Flow Volumei) +
(Outlet EMC2)(Flow Volume2) + (Outlet EMCn)( Flow Volumen)
n= number of qualified sampling events
As shown in Equation 5-3, the SOL is calculated using flow volume data. Ideally, the SOL
would be calculated by multiplying the inlet EMC by the inlet volume and the outlet EMC by the
outlet volume. As discussed in Section 5.1.1, a large discrepancy was observed in the inlet and
outlet flow volume, such that use of both the inlet and outlet volume data in the SOL calculations
would skew the results. The use of the rational formula does not provide definitive indication
that the selected volume alternative is indeed the most reasonable for the site. To demonstrate the
impact of using different volume calculations at each location, four possible combinations of the
SOL results are presented in Table 5-6 using:
inlet volumes only;
outlet volumes only;
inlet volumes for inlet SOL and outlet volumes for outlet SOL; and
inlet volumes for 2003 events and outlet volumes for 2004 events.
Table 5-6. Sediment Sum of Loads Efficiencies Calculated Using Various Flow Volumes
SOL Removal Efficiency (%)
Flow Location
Utilized method1
Inlet only
Outlet only
Inlet and outlet
TSS
33
48
26
6.3
SSC
82
89
78
83
TKN
31
29
29
35
Phosphorus
27
34
22
31
Nitrate
16
6
17
19
Cadmium
23
31
22
31
Copper
-15
-14
-13
-14
Lead
-56
-55
-55
-55
Zinc
9.1
-1.8
5.0
-1.8
1. Utilized method uses inlet volumes for 2003 SOL calculations and outlet volumes for 2004 calculations.
25
-------
The data demonstrates that using the either only the inlet or outlet volumes had a modest impact
on the resulting SOL calculations. Therefore, in spite of the sizable differences between inlet and
outlet flow calculations, the data can still be utilized in a way that provides a meaningful
representation of the performance of the Bay Saver during the 15 qualified events.
Sediment: Table 5-7 summarizes results for the SOL calculations for TSS and SSC. The TSS
analytical procedure tends to measure only the lighter, finer particles in a sample, while the SSC
analytical procedure measures both lighter, finer sediment and heavier, coarser sediment. The
SOL analyses indicate a TSS reduction of 33% and SSC reduction of 82%. The large
discrepancy in TSS versus SSC SOL is based on the difference in testing methodology between
TSS and SSC, and the high SSC inlet concentrations reported during the first four storm events
(see Section 5.2.1). Approximately 40% of the total calculated SSC mass is attributable to the
first storm event, when the inlet auto sampler was collecting a high proportion of sediment, as
measured by the SSC analytical procedure. The TSS analytical procedure tends to measure only
the finer particles in a sample, while the SSC analytical procedure measures all of the sediment
(fine and coarse) in the sample. Since stormwater BMP systems are generally more effective at
treating coarse sediment, the SSC SOL tends to show higher removal efficiency.
Nutrients: The SOL data for nutrients are summarized in Table 5-8. Total phosphorus was
reduced by 27%, nitrate was reduced by 16%, and TKN was reduced by 31%. The nitrite inlet
and outlet concentrations were near or below the method detection limits during each event,
which prevented a representative SOL reduction value from being calculated.
Metals: The SOL data for metals are summarized in Table 5-9. Total copper was reduced by
-15%, total lead was reduced by -56%, and total zinc was reduced by 9.1%. Total cadmium was
reduced by 23%; however, as discussed in Section 5.2.1, the cadmium inlet and outlet
concentrations being near or below the method detection limits should be taken into
consideration in projecting the Bay Saver's actual cadmium treatment capability.
26
-------
Table 5-7. Sediment Sum of Loads Results
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Runoff
Volume
(gallons)
46,100
51,900
74,400
43,800
47,000
64,700
63,300
56,800
68,800
63,300
114,000
99,100
21,000
30,700
91,500
Sum of the loads
Removal
Inlet
(Ib)
72.3
4.76
117
6.57
10.2
21.6
24.3
18.0
10.3
11.6
24.7
20.7
3.15
67.6
42.7
455
efficiency (%)
TSS
Outlet
(Ib)
4.61
34.2
9.92
11.0
10.2
29.1
33.2
22.3
24.1
16.9
26.6
19.8
6.65
28.9
25.2
303
33
Inlet
(Ib)
1,020
309
517
417
18.8
36.7
28.5
15.6
14.9
23.2
39.9
24.8
7.18
45.0
71.7
2,590
SSC
Outlet
(Ib)
88.0
24.2
13.0
9.49
22.3
43.7
39.1
26.0
35.6
55.9
33.3
22.3
7.70
15.6
35.1
471
82
27
-------
Table 5-8. Nutrients Sum of Loads Results
TKN
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Runoff
Volume (gal)
46,100
51,900
74,400
43,800
47,000
64,700
63,300
56,800
68,800
63,300
114,000
99,100
21,000
30,700
91,500
Sum of the loads
Removal
efficiency ('
%)
Inlet
Ob)
1.69
0.22
0.50
0.95
0.51
1.02
0.95
0.24
0.23
0.69
0.95
0.99
0.37
0.26
1.14
10.7
Outlet
Ob)
0.50
0.39
0.43
0.51
0.67
0.59
0.69
0.28
0.52
0.53
0.76
2.15
0.25
0.20
0.69
9.15
14
Phosphorus
Inlet
db)
0.27
0.03
0.08
0.08
0.05
0.25
0.13
0.08
0.05
0.04
0.24
0.16
0.03
0.03
0.14
1.65
Outlet
db)
0.06
0.04
0.07
0.04
0.07
0.12
0.11
0.09
0.06
0.04
0.24
0.17
0.03
0.01
0.08
1.21
27
Nitrate
Inlet
Ob)
0.04
0.20
ND
ND
0.18
0.28
0.43
0.13
0.83
0.19
0.17
0.18
0.07
0.08
1.27
4.05
Outlet
Ob)
0.04
0.27
ND
ND
0.13
0.17
0.23
0.16
0.68
0.73
0.06
0.17
0.14
0.06
0.57
3.41
16
NA: Not analyzed due to expiration of hold time.
ND: Not determined because both inlet and outlet samples were below detection limits.
Values in boldface text represent results where one-half the method detection limit was substituted for values
below detection limits to calculate SOL reduction.
28
-------
Table 5-9. Metals Sum of Loads Results
Total Copper
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Runoff
Volume (gal)
46,100
51,900
74,400
43,800
47,000
64,700
63,300
56,800
68,800
63,300
114,000
99,100
21,000
30,700
91,500
Sum of the Loads
Removal
Efficiency (
%)
Inlet
Ob)
ND
0.0043
0.012
0.0073
0.0039
0.016
0.016
0.009
0.0034
0.0042
0.0095
0.0074
0.0035
0.0026
0.015
0.12
Outlet
Ob)
ND
0.013
0.0062
0.0073
0.0078
0.022
0.016
0.009
0.0075
0.0053
0.0095
0.0074
0.0035
0.0026
0.015
0.13
-14
Total Lead
Inlet
db)
0.012
0.0087
0.037
0.018
0.0078
0.065
0.074
0.028
0.017
0.032
0.019
0.017
0.011
0.005
0.076
0.43
Outlet
db)
0.00038
0.056
0.025
0.011
0.031
0.13
0.12
0.04
0.052
0.047
0.029
0.025
0.019
0.010
0.069
0.67
-56
Total Zinc
Inlet
Ob)
0.031
0.061
0.087
0.058
0.043
0.10
0.20
0.070
0.034
0.047
0.057
0.066
0.025
0.072
0.13
1.1
Outlet
Ob)
0.023
0.16
0.050
0.037
0.082
0.11
0.14
0.070
0.052
0.047
0.067
0.074
0.028
0.020
0.076
1.0
9.1
ND: Not determined because both inlet and outlet samples were below detection limits.
Values in boldface text represent results where one-half the method detection limit was substituted for values
below detection limits to calculate SOL reduction.
29
-------
5.3 Particle Size Distribution
Particle size distribution analysis was conducted as part of the SSC analysis by the USGS
laboratory. The SSC method includes a "sand/silt split" analysis determined the percentage of
sediment (by weight) larger than 62.5 jim (defined as sand) and less than 62.5 jim (defined as
silt). The particle size distribution results are summarized in Table 5-10. The first four events had
a very high proportion of sand in the inlet samples compared with the last eleven events. This is
attributable to the location of the inlet sample intake port explained in Section 5.2.2. The
Bay Saver reduced the percentage of sand in the outlet sample for all 15 events. The outlet had a
higher proportion of silt than the inlet, indicating that the BaySaver removed a higher proportion
of larger particles.
The SOL can be recalculated for SSC concentrations and "sand/silt split" data to determine the
proportion of sand and silt removed during treatment. This evaluation shows that the majority of
the sediment removed was of the larger particle size.
Table 5-10. Particle Size Distribution Analysis Results
Event
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Date
3/5/03
3/15/03
1 1/27/03
12/13/03
5/12/04
5/18/04
6/12/04
6/14/04
6/27/04
6/28/04
6/30/04
8/10/04
8/21/04
10/29/04
11/12/04
Runoff
volume
(gal)
46,100
51,900
74,400
43,800
47,000
64,700
63,300
56,800
68,800
63,300
114,000
99,100
21,000
30,700
91,500
Sand (>62.5 um)
Inlet Outlet
(%)
97.6
95.5
96.5
96.7
34.8
40.4
42.4
14.6
41.7
52.5
30.7
47.1
42.0
51.7
44.7
(%)
45.3
10.6
9.2
6.3
16.6
33.9
16.1
13.6
17.2
3.1
21.4
44.4
17.9
35.9
28.9
Silt (<62.5 urn)
Inlet Outlet
(%)
2.4
4.5
3.5
3.3
65.2
59.6
57.6
85.4
58.3
47.5
69.3
52.9
58.0
48.3
55.3
(°/<
54
89
90
93
83
66
83
86
82
96
78
55
82
64
71
«)
.7
.4
.8
.7
.4
.1
.9
.4
.8
.9
.6
.6
.1
.1
.1
Sum of the loads
Removal
efficiency (°/
'o)
Sand SOL
Inlet Outlet
(Ib)
1,000
300
500
390
6.5
15
12
2.3
6.2
12
12
12
3.0
23
32
2,300
95
(Ib)
40
2.6
1.2
0.6
3.7
15
6.3
3.5
6.1
1.7
7.1
9.9
1.4
5.6
10.1
120
Silt SOL
Inlet Outlet
(Ib)
25
14
18
13
12
22
16
13
8.7
11
28
13
4.2
22
40
260
(Ib)
48
22
12
8.9
19
29
33
23
29
54
26
12
6.3
10
25
360
-38
30
-------
5.4 TCLP Analysis
At the end of the verification program, the BaySaver manholes were pumped of liquids and
retained sediments (see Chapter 7). A representative composite sample of the sediment removed
from the manholes was sent to the laboratory for TCLP metals analysis. These results shown in
Table 5-11 indicate that any metals present in the solids were not teachable and the sediment was
not hazardous. Therefore, it could be disposed of in a standard Subtitle D solid waste landfill or
other appropriate disposal location. The solids collected in the BaySaver were taken to the local
municipal landfill for disposal, in accordance with and as allowed by local and state regulations.
Table 5-11. TCLP Results for Cleanout Solids
Regulatory Hazardous
Parameter TCLP Result (mg/L) Waste Limit (mg/L)
Arsenic <0.2 5.0
Barium 0.7 100
Cadmium 0.02 1.0
Chromium <0.01 5.0
Copper 0.14 NA
Lead 1.7 5.0
Mercury <0.005 0.2
Nickel 0.06 NA
Selenium <0.5 LO
NA: Not applicable.
-------
Chapter 6
QA/QC Results and Summary
The Quality Assurance Project Plan (QAPP) in the test plan identified critical measurements and
established several QA/QC objectives. The verification test procedures and data collection
followed the QAPP. QA/QC summary results are reported in this section, and the full laboratory
QA/QC results and supporting documents are presented in Appendix D.
6.1 Laboratory/Analytical Data QA/QC
6,1.1 Bias (Field Blanks)
Field blanks were collected at both the inlet and outlet samplers to evaluate the potential for
sample contamination through the automatic sampler, sample collection bottles, splitters, and
filtering devices. The field blank was collected on May 9, 2003, allowing PCG to review the
results early in the monitoring schedule.
Results for the field blanks are shown in Table 6-1. The data identified detectable concentrations
of TKN and zinc in the outlet blank sample, and TKN and phosphorus in the inlet blank sample.
TSS and nitrate-nitrite nitrogen concentrations were below detection limits in both the inlet and
outlet blank samples.
After reviewing the analytical data, the TO hypothesized that the TKN, phosphorous and zinc
contribution could have resulted from incomplete rinsing of the sample containers following
decontamination procedures that utilized a detergent that contains these compounds. On July 25,
2003, the TO repeated decontamination procedures, including a thorough rinsing of the sample
containers, and collected additional samples to analyze for those constituents identified during
the May sampling event. The data showed a residual concentration of total zinc in the inlet blank
sample and TKN slightly above the detection level in the outlet blank sample. These results show
that an acceptable level of contaminant control in field procedures was achieved.
Table 6-1. Field Blank Analytical Data Summary
May 9, 2003 July 25, 2003
Parameter
Nitrite-nitrite nitrogen
Phosphorus
TKN
TSS
Total cadmium
Total copper
Total lead
Total zinc
Units
mg/L as N
mg/L as P
mg/L as N
mg/L
mg/L
mg/L
mg/L
mg/L
Inlet
<0.1
0.56
1.2
<5
O.0005
<0.004
<0.005
<0.004
Outlet
<0.1
<0.02
0.7
<5
O.0005
<0.004
<0.005
0.005
Inlet
NA
NA
<0.4
NA
NA
NA
NA
0.02
Outlet
NA
NA
0.5
NA
NA
NA
NA
<0.02
NA: Not analyzed
32
-------
6.1.2 Replicates (Precision)
Precision measurements were performed by the collection and analysis of duplicate samples. The
relative percent difference (RPD) recorded from the sample analyses was calculated to evaluate
precision. RPD is calculated using the following formula:
%RPD = - x 100%
where:
xi = Concentration of compound in sample
x_2 = Concentration of compound in duplicate
x = Mean value of xi and X2
Field precision: Field duplicates were collected to monitor the overall precision of the sample
collection and analysis procedures. Duplicate inlet and outlet samples were collected during
three different storm events to evaluate precision in the sampling process and analysis. The
duplicate samples were processed, delivered to the laboratory, and analyzed in the same manner
as the regular samples. Summaries of the field duplicate data are presented in Table 6-2.
The RPD data show an acceptable level of precision, with a few parameters outside generally
accepted limits. Below is a discussion on the results from selected parameters.
Nitrate and Nitrite: Nitrite replicates were all below detection limits. The RPD values for nitrate
indicate a relatively low precision (high RPD values). The poorer precision for the inlet samples
could be due to the sample handling and splitting procedures, or sampling handling for analysis,
or a combination of factors. It appears that the low precision is most prevalent in the nitrates, and
does not appear in other parameters.
TKN: In general, TKN concentrations were consistent, and RPDs were within moderate ranges,
with the exception of the inlet sample on the second duplicate event, where the second replicate
was close to the detection limit.
TSS: TSS showed good precision, with the RPD values ranging from 6 to 30%.
Phosphorus: The RPD for the inlet and outlet samples for the third duplicate were high, showing
low precision for these samples. For the third duplicate, the first replicate was two to three times
the concentration of the replicates for the other two duplicate events, attributing to the high RPD
value.
Metals: In general, metals showed good precision. Replicates with higher RPD values occurred
when the samples were near the laboratory detection limit.
33
-------
Laboratory precision: AST analyzed duplicate samples from aliquots drawn from the same
sample container as part of their QA/QC program. Summaries of the laboratory duplicate data
are presented in Table 6-3.
Table 6-2. Field Duplicate Sample Relative Percent Difference Data Summary
Parameter Units
Duplicate 1 Duplicate 2 Duplicate 3
Rep la Rep Ib RPD Rep 2a Rep 2b RPD Rep 3a Rep 3b RPD
Nitrite
Nitrate
Phosphorus
TKN
TSS
Cadmium
Copper
Lead
Zinc
mg/L as N
mg/L as N
mg/L as P
mg/L as N
mg/L
mg/L
mg/L
mg/L
mg/L
Inlet
Outlet
Inlet
Outlet
Inlet
Outlet
Inlet
Outlet
Inlet
Outlet
Inlet
Outlet
Inlet
Outlet
Inlet
Outlet
Inlet
Outlet
<0.01
<0.01
1.45
1.19
0.08
0.11
0.4
0.9
18
42
<0.001
<0.001
0.006
0.013
0.026
0.091
0.06
0.092
<0.01
<0.01
0.19
1.19
0.08
0.1
0.6
0.8
14
36
<0.001
<0.001
0.009
0.015
0.05
0.12
0.061
0.086
0
0
154
0
0
10
40
12
25
15
0
0
40
14
63
27
2
7
<0.01
0.01
0.36
1.38
0.08
0.07
1.3
1
22
32
0.0006
<0.001
0.008
0.01
0.064
0.091
0.086
0.086
<0.01
<0.005
2.26
2.82
0.08
0.07
0.4
1.1
24
30
<0.0003
<0.001
0.007
0.009
0.067
0.09
0.095
0.1
0
67
145
69
0
0
106
10
9
6
67
0
13
11
5
1
10
15
<0.01
<0.01
0.18
0.06
0.25
0.25
1
0.8
26
28
<0.001
<0.001
0.01
0.01
0.02
0.03
0.06
0.07
<0.01
<0.01
0.28
0.2
0.13
0.06
0.7
0.6
30
38
<0.001
<0.001
0.01
0.004
0.06
0.02
0.1
0.05
0
0
43
108
63
123
35
29
14
30
0
0
0
86
100
40
50
33
Values in boldface text represent results where one-half the method detection limit was substituted for values below
detection limits to calculate RPD.
The laboratory control data show that the laboratory maintained good precision throughout the
course of the study, with most of the parameters falling within acceptable limits. The laboratories
analyzed laboratory control samples as part of their ongoing analysis process. The laboratory
control samples were reviewed, and all methods were found to be in control (within established
laboratory precision limits). Laboratory procedures, calibrations, and data were audited and
found to be in accordance with the published methods and good laboratory practice.
The field and analytical precision data combined suggest that the variability and insolubility of
pollutant loadings in stormwater and the difficulty of collecting representative stormwater
samples are the likely cause of poor precision, and apart from the field sample splitting
procedures for inlet samples, the verification program maintained high precision.
34
-------
Table 6-3. Laboratory Duplicate Sample Relative Percent Difference Data Summary
Parameter Count
Standard
Average Maximum Minimum Deviation Objective
Cadmium
Chromium
Nitrite
Nitrate
Phosphorus
Lead
TKN
TSS
Zinc
29
29
25
25
31
29
29
29
29
112
101
105
98
104
105
93
97
104
130
111
109
102
110
118
110
103
119
95
92
102
92
93
96
72
91
98
11
4.6
2.0
2.7
4.2
4.2
11
3.0
4.5
83-
85-
97-
88-
91-
85-
67-
89-
85-
135
115
112
107
115
115
126
109
115
6.1.3 Accuracy
Method accuracy was determined and monitored using a combination of matrix spike/matrix
spike duplicates (MS/MSD) and laboratory control samples (known concentration in blank
water). The MS/MSD data are evaluated by calculating the percent recovery based on the
measured result of the spiked sample and the calculated "true" value of the spiked sample
(measured sample result plus spiked amount). Laboratory control data are evaluated by
comparing the measured concentration in the control sample with the known true value of the
control sample, and calculating the percent recovery. Accuracy was in control throughout the
verification test. Tables 6-4 and 6-5 summarize the matrix spikes and lab control sample
recovery data, respectively.
Table 6-4. Laboratory MS/MSD Data Summary
Parameter Count
Standard
Average Maximum Minimum Deviation Objective
Cadmium
Copper
Nitrite
Nitrate
Phosphorus
Lead
TKN
TSS
Zinc
30
30
26
26
32
30
30
30
30
104
107
104
99
106
104
88
108
108
125
129
110
120
120
118
119
318
318
87
92
95
89
95
92
62
70
70
9.9
10
3.5
5.9
5.0
6.4
15
43
43
80-
80-
75-
75-
80-
80-
75-
75-
80-
120
120
125
125
120
120
125
125
120
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The balance used for TSS analyses was calibrated routinely with weights that were NIST
traceable. The laboratory maintained calibration records. The temperature of the drying oven was
also monitored using a thermometer that was calibrated with an NIST traceable thermometer.
Table 6-5. Laboratory Control Sample Data Summary
Standard
Average Maximum Minimum Deviation Objective
Parameter Count (%) (%) (%) (%) (%)
Cadmium
Chromium
Nitrite
Nitrate
Phosphorus
Lead
TKN
TSS
Zinc
29
29
25
25
31
29
29
29
29
112
101
105
98
104
105
93
97
104
130
111
109
102
110
118
110
103
119
95
92
102
92
93
96
72
91
98
11
4.6
2.0
2.7
4.2
4.2
11
3.0
4.5
83-
85-
97-
88-
91-
85-
67-
89-
85-
135
115
112
107
115
115
126
109
115
6.1.4 Representativeness
The field procedures were designed to ensure that representative samples were collected of both
inlet and outlet stormwater. Field duplicate samples and supervisor oversight provided assurance
that procedures were being followed. The challenge in sampling stormwater is obtaining
representative samples. The data indicated that while individual sample variability might occur,
the long-term trend in the data was representative of the concentrations in the stormwater, and
redundant methods of evaluating key constituent loadings in the stormwater were utilized to
compensate for the variability of the laboratory data.
The laboratories used standard analytical methods, with written SOPs for each method, to
provide a consistent approach to all analyses. Sample handling, storage, and analytical
methodology were reviewed to verify that standard procedures were being followed. The use of
standard methodology, supported by proper quality control information and audits, ensured that
the analytical data were representative of actual stormwater conditions.
As described in Chapter 5, the inlet and outlet flow and volume data did not correlate. The
Bay Saver is designed so that all of the water entering through the inlet eventually passes through
the outlet, so the inlet and outlet volumes should have been the same. This was not the case. A
review of the hydrographs and the depth, velocity and flow data did not clearly identify one set
of data as being more representative than the other. When the characteristics of the drainage
basin and the rain depth were input into the rational formula and compared against the recorded
flow data, the inlet flow volumes for the first four events and the outlet volumes for the last
eleven events appeared to be most representative of the actual flow measurements.
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The flow values are multiplied by the constituent analytical concentrations in order to determine
the sum of loads efficiency of the BaySaver for each measured constituent. In spite of the large
differences between recorded inlet and outlet flow volumes, different combinations of inlet and
outlet flow volumes in the sum of loads calculations yielded only minor differences in the
calculated sum of loads efficiency.
6.1.5 Completeness
Completeness is a measure of the number of valid samples and measurements that are obtained
during a test period. Completeness will be measured by tracking the number of valid data results
against the specified requirements of the test plan.
Completeness was calculated by the following equation:
Percent Completeness = (V / T) x 100% (6-3)
where:
V = Number of measurements that are valid.
T = Total number of measurements planned in the test.
The goal for this data quality objective was to achieve minimum 80% completeness for flow and
analytical data. The data quality objective was exceeded, with discrepancies noted below:
The flow data is 100% complete for all of the monitored events.
Two sets of nitrate and nitrite samples (from events 3 and 4) were not analyzed by the
analytical laboratory because the 48-hr hold times had been exceeded.
These issues are appropriately flagged in the analytical reports and the data used in the final
evaluation of the BaySaver device.
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Chapter 7
Operations and Maintenance Activities
7.1 System Operation and Maintenance
Operation of a properly installed BaySaver consists of periodic inspection and maintenance.
Bay Saver's Technical and Design Manual indicates that maintenance is required once two feet of
sediment have accumulated on the floor of either manhole. Typical maintenance consists of
removing and disposing of the water, sediment, and pollutants accumulated in the manholes. The
manholes may be accessed through 30-in. manhole covers, and the accumulated materials may
be removed with a vacuum truck. BaySaver indicates this procedure typically takes two to four
hours.
The BaySaver was maintained in December 2002, prior to testing. A second maintenance event
was conducted on November 30, 2004, under the supervision of PCG and NSF. The City of
Griffin provided a vacuum truck and operating personnel. Floating debris and a hydrocarbon
sheen were visible inside both manholes. Water was decanted from the sediment in both
manholes so that the sediment layer could be visually examined. The primary manhole contained
approximately 3,000 gallons of debris and water and approximately two feet of accumulated
sediment, while the storage manhole contained approximately 1,200 gallons of water and
approximately two inches of accumulated sediment. The maintenance event took approximately
2.5 hr, and no significant issues were noted.
While conducting verification testing, the TO noticed that during extended dry-weather periods,
the water level in the manholes would fall below the outlet elevations, indicating a possible leak.
Apparently, a joint between the BaySaver separation unit and the concrete manholes was not
watertight. On December 3, 2003, this issues was corrected by entering the concrete manhole
and regrouting the seams.
The VO conducted numerous maintenance activities associated with the auto samplers, and the
inlet auto sampler in particular, throughout the verification period. As discussed in Chapter 5, the
inlet sample intake port appeared to obstruct the pipe, allowing for sediment to collect and
preventing the auto sampler from functioning properly. This situation was corrected by moving
the inlet sample port approximately ten inches to the side of the inlet pipe invert. This
modification proved to be successful in allowing the auto sampler to function during storm
events, but a review of the sediment analytical data shows that the inlet SSC concentrations
decreased dramatically after this change was made. As discussed in Section 5.2.2, the inlet TSS
and SSC concentrations were lower than the corresponding outlet solids concentration in more
than 60% of the 2004 events. This in turn yielded negative removal efficiencies for most of the
2004 storm events.
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Chapter 8
Vendor-Supplied Information
The following information is the evaluation and opinion of the vendor, BaySaver Technologies,
Inc. This information has not been verified and does not necessarily represent the findings or
conclusions of the Testing Organization or Verification Organization.
Stormwater device performance analysis is a complex endeavor. Some of these experimental
requirements are prone, like any other complex process analysis projects, to unforeseen technical
difficulties. It is our opinion that as a result of the technical difficulties encountered during this
study and the corrective actions that followed, the results derived from this report do not
accurately or reliably verify the performance of the verified BaySaver Separation System, Model
10K.
After careful data review, it became evident that this Griffin study unfortunately had serious
problems with the solids sampling and analytical procedures. These problems made the solids
analysis data asymmetric and difficult, if not impossible, to correlate and draw valid conclusions
from, especially from an overall performance verification perspective. Given that solids removal
is the pivotal parameter in stormwater BMP performance analysis, these problems make the
results derived from this report of limited intrinsic value.
It is important to note that neither the testing organization nor verification organization analyzed
the testing outcomes from the perspective BaySaver did, so our specific conclusions may not be
mentioned explicitly in this verification report. Since this project collected copious amounts of
data, BaySaver concentrated on the most salient and relevant discrepancies, and not on a
statistical analysis of relevance, since it was not deemed essential for the purpose of this
comment section.
8.1 TSS and SSC Data
BaySaver believes that the Total TSS data suffers fundamental inaccuracies. As shown in Table
5-3, the inlet TSS concentrations for the 2003 storm events are one to two orders of magnitude
lower than the corresponding SSC concentrations. As explained in greater detail in Chapter 5 of
this report, the TSS analytical procedure captures only a fraction of the total particles in the
sample while the SSC procedure captures all of the particles in the sample.
Data presented in a USGS study (Grey et. al., 2000) indicates that TSS and SSC numbers had, on
average, the same order of magnitude when 3,250 TSS and SSC data points were analyzed.
Therefore, the difference encountered in this study appears to be extraordinary. The outlet TSS
determinations for 2003 are higher than the inlet concentrations 50% of the time, and there is no
explanation for this trend. For the 2004 storm events, this large difference between TSS and SSC
diminished. BaySaver believes this change in the inlet solids concentration data was caused by
the corrective action taken to solve the inlet sample tube clogging. At the same time this well
intended measure generated a fundamental error in the TSS and SSC inlet data for the rest of the
test as discussed next.
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8.2 Sampling Procedure
Prior to the first storm event sampled in 2004, the inlet sample tube was moved from the pipe
invert approximately 10 in. along the inside of the 42 in. HDPE pipe to avoid solids clogging of
the sample tube. The outlet sampling tube remained in the same location, at the invert, for the
duration of the test. While this action resolved the inlet sampling tube-clogging issue, Bay Saver
believes it also affected the inlet TSS and SSC data in a fundamental way, making it asymmetric
with respect to the outlet data. By moving the inlet sample port up 10 in., this elevated the
sample drawing point approximately 2.5 in. above the invert. Since heavier solids tend to travel
along the bottom of the pipe, this biased the sampling towards sampling the smaller, lighter
particles. At the same time, the outlet sampler continued to capture the solids traveling along the
invert. BaySaver believes this greatly contributed to the tendency towards higher solids readings
in the outlet than in the inlet. This anticipated effect is indeed reflected in the negative solids
removal efficiencies shown in Table 5-3. This anticipated discrepancy is corroborated in the
dramatic change in particle sizes between 2003 and 2004 when the inlet sample location was
changed shown in Table 5-10.
8.3 Conclusions
Based on the above observations, BaySaver concludes that:
The 2004 inlet/outlet solids concentration data cannot be used to obtain accurate solids
removal efficiencies. The solids generation characteristic associated with the BaySaver
BMP during most of the 2004 storm events is not consistent with mass conservation
principles.
The TSS data determinations for 2003 appear to have extraordinary deviations with
respect to the corresponding SSC data and there is no fundamental explanation to account
for these discrepancies.
The reader is encouraged to read this report in light of our observations and to contact
BaySaver and the verification organization to discuss the data and results derived from
this project. It is our goal to keep contributing to the field of stormwater treatment
technology and to make future testing efforts fruitful.
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Chapter 9
References
1. APHA, AWWA, and WEF. Standard Methods for the Examination of Water and
Wastewater, 19th ed. Washington, DC, 1995.
2. Fishman, M. J., Raese, J. W., Gerlitz, C. N., Husband, R. A., U.S. Geological Survey.
Approved Inorganic and Organic Methods for the Analysis of Water and Fluvial Sediment,
1954-94, USGS OFR 94-351, 1994.
3. Grey, J.R., Glysson, G.D., Turcios, L.M., Schwartz, G.E., 2000, Comparability of
Suspended-Sediment Concentration and Suspended Solids Data, US Geological Survey,
WRIR 00-4191
4. Merrit, Frederick S. Standard Handbook for Civil Engineers, Second Edition, McGraw-Hill
Book Company, 1976.
5. National Oceanic and Atmospheric Administration (NOAA). Technical Paper No. 40
Rainfall Frequency Atlas of the United States. Washington, DC, 2000.
6. NSF International and Paragon Consulting Group. Test Plan for the Verification ofBaySaver
Technologies, Inc., The BaySaver Separation System, TEA-21 Project Area, City of Griffin,
Spalding County, Georgia. June 2003.
7. NSF International. ETV Verification Protocol Stormwater Source Area Treatment
Technologies. U.S. EPA Environmental Technology Verification Program; EPA/NSF Wet-
weather Flow Technologies Pilot. March 2002 (v. 4.1).
8. United States Environmental Protection Agency. Methods and Guidance for Analysis of
Water, EPA 821-C-99-008, Office of Water, Washington, DC, 1999.
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Appendices
A BaySaver Design and O&M Guidelines
B Verification Test Plan
C Event Hydrographs and Rain Distribution
D Analytical Data Reports with QC
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