United States
Environmental Protection
Agency
:^!ice of Water
' n'orcement and Permits (EN-338)
"vshington, D.C. 20460
MAY 1988
NPDES
Compliance Inspection
Manual
-------
NPDES COMPLIANCE
INSPECTION MANUAL
May 1988
U.S. Environmental Protection Agency
Office of Water
Office of Water Enforcement and Permits
(EN-338)
401 M Street, SW
Washington, DC 20460
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
MEMORANDUM OFFICE OF
WATER
SUBJECT: NPDES Compliance Inspection Manual
FROM: Jamea/RTElder.
Office of Water Enforcement and Permits
TO: Users of the NPDES Compliance Inspection Manual
This manual is the first update of the June 1984 NPDES
Compliance Inspection Manual. The modifications include
recent changes to the regulations and citations, a new em-
phasis on bioraonitoring, and clarification on pretreatment
inspections. The manual, as revised and in the original text,
provides discussion on all major compliance inspection functions
(i.e. sampling, flow measurement, etc.) and does not focus
on any one inspection type (i.e. compliance evaluation or
compliance sampling inspection). This approach allows the
inspector to refer to specific chapters and checklists when
engaging in a particular activity which is part of an NPDES
inspection.
The inspector's primary objective is to gather information
and report facts. In order to meet this objective he/she
must have a clear understanding of the technical information
necessary to evaluate compliance and an understanding of the
regulations and NPDES program requirements. This manual will
provide the basic information to enable inspectors to focus
their efforts properly, thereby improving the effectiveness
of the inspections.
I believe that this manual will provide valuable assistance
to inspectors, for successful completion of their very important
duties. Please feel free to write to the Office of Water
Enforcement and Permits (EN-338) with suggestions, additions
or improvements to this manual.
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ACKNOWLEDGMENTS
We acknowledge the considerable efforts and cooperation of the many people
whose contributions helped successfully complete this document.
This manual was prepared under the direction of Gary Polvi with assistance
from Virginia Lathrop of OWEP, and the Inspection Materials Work Group
including Robert Reeves, Region 6; Joseph Slayton, Region 3 Central Regional
Lab; Gary Bryant, Region 3 Wheeling Office; William Peltier, EPA Region 4
EPA; Dan Tangerone, Region 10; Dan Murray, EPA Region 1; Charles Moses and
Jack Wolfe of the West Virginia Division of Water Resources; Ted Denning of
Illinois EPA; and Alton Boozer of South Carolina Department of Health and
Environmental Control. Extensive reviews were conducted by EPA Headquarters,
Regional Offices, and many State agencies during the initial development and
1987 update. These reviews provided valuable comments, most of which were
incorporated into this manual.
This manual was prepared by SRA Technologies, Inc., under EPA Contract No.
68-01-6514, and revised by SAIC under EPA Contract No. 68-01-7050.
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DISCLAIMER
This manual has been reviewed by the Office of Water Enforcement and
Permits, U.S. Environmental Protection Agency, and approved for publica-
tion. This guidance represents EPA's recommended procedures for
conducting NPDES compliance inspections only. Failure on the part of
any duly authorized official, inspector or agent to comply with its
contents shall not be a defense in any enforcement action, nor shall a
failure to comply with this guidance alone constitute grounds for
rendering evidence obtained thereby, inadmissible in a court of law.
The mention of trade names or commercial products constitutes neither
endorsement nor recommendation for use.
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FOREWORD
The National Pollutant Discharge Elimination System (NPDES) Compliance
Inspection Manual has been developed to support inspection personnel in
conducting field investigations fundamental to the NPDES compliance
program and to provide inspectors with standardized procedures for conducting
complete, accurate inspections.
The information presented in this manual will guide a qualified inspector
in conducting an accurate inspection. The manual presents standard procedures
for inspection; it is assumed the inspector has a working knowledge of
wastewater and related problems, regulations, and control technologies.
The manual will serve the experienced inspector as a flexible and easy
reference. New inspection personnel will find support in the orderly and
detailed presentation of the material.
This manual presents the most current information on NPDES compliance
inspections available at the time of publication. As new information
concerning inspection protocols and policies emerges, the manual will be
revised accordingly. Comments or changes to the present manual should be
addressed to:
Chief, Enforcement Support Branch (EN-338)
Office of Water Enforcement and Permits
U.S. Environmental Protection Agency
401 M Street, SW
Washington, DC 20460
The information contained in this manual is comprehensive and designed to
address a wide range of activities. Since each inspection may not involve
all activities, the inspector should refer to those parts applicable to the
particular inspection. Although the information is presented from the
viewpoint of the Environmental Protection Agency (EPA), it is applicable
to NPDES State inspectors and other regulatory authorities or their authorized
representatives. In particular, the Minerals Management Service may find
the manual useful for coordinating the EPA NPDES permit compliance program
with the Minerals Management Service Offshore Inspection Program.
This NPDES Compliance Inspection Manual consolidates information found in
previous inspection manuals. Although the earlier manuals are generally
still accurate and in some cases even cover technical issues in more
detail, they are organized by inspection type and may contradict this manual
on a few issues. Previous manuals do not reflect updated policy and
NPDES Inspection ManualiJanuary 1988
-------
Foreword
strategies. These previous manuals should be retained as technical references,
but in the event of contradictions, this manual takes preference.
The manual is organized into nine chapters:
• Chapter One, "Introduction," describes the NPDES program and
provides general information relating to legal authority and
inspector responsibilities.
• Chapter Two, "Inspection Procedures," discusses general procedures
common to all NPDES inspections, including pre-inspection
preparation, entry, opening conference, documentation, closing
conference, and inspection report.
• Chapters Three through Nine provide the specific technical
information necessary to conduct the full range of NPDES compliance
inspection activities. Each chapter describes procedures for the
major technical activities involved in compliance inspections:
- Chapter Three, "Recordkeeping and Reporting"
- Chapter Four, "Facility Site Review"
- Chapter Five, "Sampling"
- Chapter Six, "Flow Measurement"
- Chapter Seven, "Biomonitoring"
- Chapter Eight, "Laboratory Quality Assurance"
- Chapter Nine, "Pretreatment."
Within each chapter, tables and figures illustrate the topics discussed
in the text. These are located at the end of the chapter subsection in
which they are referenced. As appropriate, references and checklists
are provided at the end of the chapter. The checklists presented in this
manual are intended as guidance. They may be used as presented or modified
to address the needs of the inspection authority. More detailed checklists
for any individual inspection type may have also been developed by EPA
and presented in the guidance materials specific to that type of inspection.
It should be noted that the text often is written from the perspective of
the Federal Clean Water Act requirements. State NPDES inspectors using
this manual may find that State rules and procedures on such topics as
notice to the permittees may vary to some degree from the material found
in this manual. The technical material will, we hope, prove to be useful
to al 1 NPDES inspectors.
Inspection Types
This manual provides guidance applicable to each type of inspection a
NPDES inspector may be required to conduct at a wastewater facility.
These different types of inspections are described below.
NPDES Inspection Manual ii January 1988
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Foreword
Compliance Evaluation Inspection (CEI)
The CEI is a nonsampling inspection designed to verify permittee compliance
with applicable permit self-monitoring requirements and compliance
schedules. This inspection involves record reviews, visual observations,
and evaluations-of the treatment facilities, effluents, receiving waters,
etc. The CEI examines both chemical and biological self-monitoring and
forms the basis for all other inspection types except the Reconnaissance
Inspection.
Compliance Sampling Inspection (CSI)
During the CSI, representative samples required by the permit are obtained.
Chemical analyses are performed and the results are used to: verify the
accuracy of the permittee's self-monitoring program and reports; determine
the quantity and quality of effluents; develop permits; and provide
evidence for enforcement proceedings where appropriate. In addition, the
CSI includes the same objectives and tasks as a CEI.
Toxics Sampling Inspection (XSI)
The XSI has the same objectives as a conventional CSI. However, it places
increased emphasis on toxic substances regulated by the NPDES permit. The
XSI covers priority pollutants other than heavy metals, phenols, and
cyanide, which are typically included in a CSI. An XSI uses more resources
than a CSI because highly sophisticated techniques are required to sample
and analyze toxic pollutants.
Compliance Biomonitoring Inspection (CBI)
The CBI uses acute and chronic toxicity testing techniques to evaluate
the biological effect of a permittee's effluent discharye(s) on test
organisms. In addition, this inspection includes the same objectives and
tasks as a CEI.
Performance Audit Inspection (PAI)
The PAI is used to evaluate the permittee's self-monitoring program. As
with a CEI, the PAI is used to verify the permittee's reported data and
compliance through a records check. In a CEI, the inspector makes a
cursory visual observation of the treatment facility, effluents, and
receiving waters. In a PAI, the inspector actually observes the permittee
performing the self-monitoring process from sample collection and flow
measurement through laboratory analyses, data workup, and reporting.
The PAI inspector may leave a check sample for the permittee to
analyze. Compared to a CSI, the PAI is less resource intensive because
sample collection and analyses by EPA or the State are not included.
NPDES Inspection ManualTHJanuary 1988
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Foreword
Diagnostic Inspection (PI)
The DI primarily focuses on Publicly Owned Treatment Works (POTWs) that
have not achieved permit compliance. POTWs who are having difficulty
diagnosing their problems are targeted. The purposes of the DI are to
identify the causes of noncompl iance and to suggest immediate remedies
that will help the POTW achieve compliance. Once the cause of
noncompliance is defined, an administrative order is usually issued that
requires the permittee to conduct a detailed analysis and develop a
composite correction plan.
Pretreatment Compliance Inspection (PCI)
The PCI evaluates the POTW's implementation of its approved pretreatment
program. It includes a review of the POTW's records on monitoring,
inspections, and enforcement activities for its industrial users (Ills).
The PCI may be supplemented with IU inspections. An IU inspection is an
inspection of any significant ID which discharges to the POTW. The
inspection can be either a facility or sampling inspection, or both.
The PCI should be conducted concurrently with another NPDES inspection of
the POTW.
It should be noted that a related type of review procedure, the pretreatment
audit, is also performed by Approval Authorities. The pretreatment audit
is not treated in depth in this manual because it is not regarded as a
true NPOES compliance inspection. The pretreatment audit is defined and
discussed in Section 1.2, page 1.1, of the U.S. EPA guidance manual
Pretreatment Compliance Inspection and Audit Manual for Approval Authorities
(July, 1986).
Reconnaissance Inspection (RI)
The RI is used to obtain a preliminary overview of a permittee's compliance
program. The inspector performs a brief visual inspection of the permittee's
treatment facility, effluents, and receiving waters. The RI uses the
inspector's experience and judgment to summarize quickly any potential
compliance problems. The objective of the RI is to expand inspection
coverage without increasing inspection resources. The RI is the briefest
of all NPDES inspections.
Legal Support Inspection (LSI)
The LSI is a resource intensive inspection conducted when an enforcement
problem is identified as a result of a routine inspection or a complaint.
For an LSI, the appropriate resources are assembled to deal effectively
with a specific enforcement problem.
NPDES Inspection ManualTV January 1988
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Foreword
Summary
Table F-l matches minimum inspection activities with each of the inspection
types. The given activities are only minimum requirements and an
inspector is not limited to the stated activities; additional activities
may be conducted-depending upon the focus of the inspection.
The inspector should plan all activities and coordinate with compliance
personnel before the inspection. The minimum requirements may serve as a
basis for deciding what activities will be conducted on-site and for
determining what additional information is to be gathered or verified
during the inspection. Compliance personnel should choose the type of
inspection to be conducted based on: the compliance status of the
facility, the information needed from the facility, and the type of
facility involved (e.g., toxic organic effluents, Federally funded, etc.).
NPDES Inspection Manual v January 1988
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Foreword
Table F-l
Comparison of Inspection Activities With Inspection Types
INSPECTION TYPES
ACTIVITY DESCRIPTION
PRE-INSPECTION
Review Facility Background
Develop an Inspection Plan
Notification of the Facility
ENTRY ONSITE
Entry Procedures
Opening Conference
RECORDKEEPING AND REPORTING
Permit Information Verification
Evaluation Procedures
Compliance Schedule Status Review
Pretreatment Record Review
FACILITY SITE REVIEW
Physical Inspection
Operation Evaluation
Maintenance Evaluation
SAMPLING
Evaluation of Permittee Program
Inspector's Compliance Sampling
FLOW MEASUREMENT
Evaluation of Permittee Flow
Measurement
Verification of Flow Measurements
BIOMONITORING
Evaluation of Permittee Self-
Monitoring Program
Compliance Biomonitoring
LABORATORY QUALITY ASSURANCE
Sampling Techniques Evaluation
Analyses Techniques Evaluation
Laboratory Quality Assurance
Page
No.
2-1
2-4
2-5
2-11
2-15
3-3
3-3
3-5
3-7
4-3
4-13
4-14
5-1
5-3
6-1
6-35
7-1
7-9
8-3
8-5
8-9
CEI
I
0
0
I
C
I
I
C
C
C
C
C
I
-
C
C
C
-
C
C
C
CSI
I
I
0
I
C
I
I
C
C
C
C
C
I
I
I
I
C
-
C
C
C
PA I
I
0
0
I
C
I
I
C
C
C
C
C
I
-
I
C
I
-
I
I
I
CBI
I
I
0
I
C
C
C
-
-
C
C
C
0
I
I
C
I
I
C
C
C
XSI
I
I
0
I
C
I
I
C
C
C
C
C
I
I
I
C
C
-
C
C
C
DI
I
0
0
I
C
I
I
C
C
I
I
I
I
0
I
I
C
-
C
C
C
RI
I
0
0
I
C
0
C
0
-
C
C
C
C
-
C
C
_
-
C
C
C
PCI*
I
0
0
I
C
0
C
0
I
0
0
-
C
0
0
C
_
-
0
0
0
NPDES Inspection Manual
vn
January 1988
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Forward
Table F-l
Comparison of Inspection Activities With Inspection Types
(Continued)
INSPECTION TYPES
ACTIVITY DESCRIPTION
OTHER SITE ACTIVITIES
Inspection of Industrial
Discharges to POTWs
Documentation of Hazardous Waste
Storage and Disposal
Documentation of Air Pollution
Releases
Sludge Management Issues
DOCUMENTATION
Field Notes and Statements
Photographs, Drawings, and Maps
Copies of Facility Records
CLOSING PROCEDURES
Closing Conference
Notice of Deficiency
FOLLOW-UP
Inspection Form
Narrative Comments/Checklists
Input on PCS
Page
No.
-
-
.
-
2-19
2-21
2-24
2-29
2-29
2-33
2-34
2-35
CEI
-
0
0
0
I
0
0
c
c
I
I
I
CSI
-
0
0
0
I
c
0
c
c
I
I
I
PA I
-
0
0
0
I
0
0
I
I
I
I
I
CBI
-
0
0
0
I
0
0
c
c
I
I
I
XSI
-
0
0
0
I
0
0
c
c
I
I
I
DI
-
0
0
0
I
I
I
I
I
I
I
I
RI
-
0
0
0
I
c
0
c
c
I
I
I
PCI*
0
0
0
0
I
0
I
c
c
I
I
I
LEGEND
I -
C -
0 -
Activity
Activity
Activity
policy
i
i
i
s
s
s
conducted
conducted
optional ,
in
in
but
an indepth manner
a cursory manner
may be recommended by Regional or State
*The PCI has been developed to verify compliance status of the POTW and
focuses primarily on the compliance monitoring and enforcement activities
of the POTW. Inspections of indirect industrial facilities to verify
their compliance with applicable pretreatment standards is not addressed
in the description of activities listed for the PCI.
NPDES Inspection Manua'
vn i
January 1988
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TABLE OF CONTENTS
Contents Page
List of Tables xi
List of Figures xiii
List of Acronyms xv
Chapter One: Introduction
Legal Authority for NPDES Inspections 1-1
Responsibilities of the NPDES Inspector 1-3
Multimedia Concerns in NPDES Permitting and
Inspections 1-9
Chapter Two: Inspection Procedures
Pre-Inspection Preparation 2-1
Ent ry 2-11
Opening Conference 2-15
Documentation 2-19
Closing Conference 2-29
Inspection Report 2-33
Chapter Three: Recordkeeping and Reporting
Inspection Authority and Objectives 3-1
Evaluation Procedures 3-3
Verification, Recordkeeping, and Reporting Evaluation
Checklist 3-9
Chapter Four: Facility Site Review
Objectives 4-1
Physical Inspection of the Facility 4-3
Operation and Maintenance Evaluation 4-13
References and Facility Site Review Checklist 4-25
NPDES Inspection ManualTxJanuary 1988
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Table of Contents
TABLE OF CONTENTS (Continued)
Contents Page
Chapter Five: Sampling
Evaluation of Permittee Sampling Program and Compliance
Sampling 5-1
Sampling Procedures a/id Techniques 5-3
References and Permittee Sampling Inspection Checklist .... 5-23
Chapter Six: Flow Measurement
Evaluation of Permittee's Flow Measurement 6-1
Supplementary Information 6-5
Flow Measurement Compliance 6-29
References and Flow Measurement Inspection Checklist 6-37
Chapter Seven: Biomonitoring
Evaluation of Permittee Self-Biomonitoring Program 7-1
Compliance Biomonitoring Inspection 7-9
Chapter Eight: Laboratory Quality Assurance
Objectives and Requirements 8-1
Sample Handling Procedures 8-3
Laboratory Analyses Techniques Evaluation 8-5
Quality Assurance and Quality Control 8-9
References and Laboratory Quality Assurance Checklist 8-13
Chapter Nine: Pretreatment
Review of the General Pretreatment Regulations 9-1
Pretreatment Compliance Inspections (PCIs) and Audits 9-19
References 9-25
NPDES Inspection Manual x January 1988
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LIST OF TABLES
Table Page
F-l Comparison of Inspection Activities with Inspection
Types
1-1 Responsibilities of the Inspector in the Inspection
Process 1-7
2-1 NPDES-Related Statutes and Regulations 2-7
4-1 Operations and Maintenance Function Evaluation
Questions 4-17
5-1 Volume of Sample Required for Determination of the
Various Constituents of Industrial Wastewater 5-9
5-2 Compositing Methods 5-12
5-3 Required Containers, Preservation Techniques, Holding
Times, and Test Methods 5-13
6-1 Head-Discharge Relationship Formulas for Nonsubmerged
Weirs 6-11
6-2 Discharge of 90° V-Notch Weir - Head Measured
at Weir Plate 6-12
6-3 Minimum and Maximum Recommended Flow Rates for
Cipolletti Weirs 6-13
6-4 Minimum and Maximum Recommended Flow Rates for Free
Flow Through Parshall Flumes 6-13
6-5 Free-Flow Values of C and N for Parshall Flume Based
on the Relationship Q = CWHan 6-14
6-6 Minimum and Maximum Recommended Flow Rates for Free
Flow Through Plasti-Fab Palmer-Bowlus Flumes 6-15
NPDES Inspection ManualxiJanuary 1988
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List of Tables
LIST OF TABLES (Continued)
Table Page
6-7 Coefficients of Discharge c for Venturi Meters 6-16
6-8 Values of K in Formula for Venturi Meters 6-16
6-9 Advantages and Disadvantages of Secondary Devices 6-17
7-1 Recommended Species, Test Temperatures, and Life
Stages 7-5
9-1 Summary of the General Pretreatment Regulations 9-9
9-2 Summary Status of National Categorical Pretreatment
Standards: Milestone Dates 9-14
NPDES Inspection ManualxTlJanuary
-------
LIST OF FIGURES
Figure Page
2-1 Sample 308 Letter 2-9
2-2 EPA Deficiency Notice Form 2-31
2-3 NPDES Compliance Inspection Report Form 2-37
5-1 Example Chain-of-Custody Form 5-21
6-1 Profile and Nomenclature of Sharp-Crested Weirs 6-19
6-2 Three Common Types of Sharp-Crested Weirs 6-20
6-3 Flow Rates for 60° and 90° V-Notch Weirs 6-21
6-4 Nomograph for Capacity of Rectangular Weirs 6-22
6-5 Flow Curves for Parshall Flumes 6-23
6-6 Dimensions and Capacities of Parshall Measuring
Flume for Various Throat Widths 6-24
6-7 Effect of Submergence on Parshall Flume Free
Discharge 6-26
6-8 Free Flowing Palmer-Bowl us Flume 6-27
6-9 Configuration and Nomenclature of Venturi Meter 6-27
6-10 Electromagnetic Flowmeter 6-28
6-11 Propeller Flowmeter 6-28
7-1 NPDES Toxicity Test Evaluation Form 7-7
NPDES Inspection Manual xiii January 1988
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LIST OF ACRONYMS
Acronym
Full Phrase
BCT/BAT Best Control Technology/Best Available Technology
BMP Best Management Practices
BODs Biochemical Oxygen Demand
CAA Clean Air Act
CBI Compliance Biomonitoring Inspection
CEI Compliance Evaluation Inspection
CERCLA Comprehensive Environmental Response, Compensation, and
Liability Act
CFR Code of Federal Regulations
CSI Compliance Sampling Inspection
CWA Clean Water Act
CWF Combined Wastestream Formula
DI Diagnostic Inspection
DMR Discharge Monitoring Report
DO Dissolved Oxygen
EC50 Concentration which causes an effect in 50% of the test
organisms
EMSL EPA Environmental Monitoring System Laboratory
EPA Environmental Protection Agency
FIFRA Federal Insecticide, Fungicide and Rodenticide Act
FR Federal Register
GC Gas Chromotography
GC/MS Gas Chromotography/Mass Spectroscopy
IWC Instream Waste Concentration
LC Lethal Concentration
LC50 Concentration at which 50% of the test organisms die in a
specified time period
LD50 Dose at which 50% of the test organisms die in a specific
time period
LOEC Lowest-Observed-Effect-Concentration
LSI Legal Support Inspection
MPRSA Marine Protection, Research, and Sanctuaries Act
NOEL No-Observed-Effect-Level
NPDES National Pollutant Discharge Elimination System
O&M Operation and Maintenance
OSHA Occupational Safety and Health Administration
NPDES Inspection Manual
xv
January 1988
-------
List of Acronyms
LIST OF ACRONYMS (Continued)
Acronym Full Phrase
PAI Performance Audit Inspection
PCB Polychlorinated Biphenyl
PCI Pretreatment Compliance Inspection
PCS Permit Compliance System
POTW Publicly Owned Treatment Works
QA Quality Assurance
QC Quality Control
QNCR Quarterly Noncompliance Report
R&D Research and Development
RBC Rotating Biological Contactor
RCRA Resource Conservation and Recovery Act
RI Reconnaissance Inspection
SAIC Science Applications International Corporation
SPCC Spill Prevention Control and Countermeasure Plan
SRA Social Research Associates, Inc.
TCDD Tetrachlorodibenzodioxin
TSCA Toxic Substances Control Act
TSD Technical Support Document
TSDF Treatment, Storage, and Disposal Facility
TSS Total Suspended Solids
USC United States Code
USGS United States Geologic Survey
XSI Toxics Sampling Inspection
NPDES Inspection Manual xvi January 1988
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Chapter One
INTRODUCTION
Contents Page
A Legal Authority for NPDES Inspections
Inspection Authority 1-1
State Program Authority 1-1
B Responsibilities of the NPDES Inspector
Legal Responsibilities 1-3
Procedural Responsibilities 1-3
Inspection Procedures 1-3
Evidence Collection 1-4
Safety Responsibilities 1-4
Professional Responsibilities 1-5
Professional Attitude 1-5
Attire 1-5
Gifts, Favors, Luncheons 1-5
Requests for Information 1-6
Quality Assurance Responsibilities 1-6
C Multimedia Concerns in NPDES Permitting and Inspections
Surface Water Discharges 1-9
Intermedia Transfers Resulting From Wastewater Treatment .... 1-10
Summary 1-11
List of Tables
1-1 Responsibilities of the Inspector in the Inspection
Process 1-7
NPDES Inspection Manual 1-i January 1988
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Chapter One
A LEGAL AUTHORITY FOR NPDES
INSPECTIONS
The Federal Water Pollution Control Act of 1972, as amended by the Clean
Water Act (CWA or the Act) of 1977 and the Water Quality Act of 1987,
gives the Environmental Protection Agency (EPA) the authority to regulate
the discharge of pollutants to waters of the United States. The Act
provides broadly defined authority to: establish the National Pollutant
Discharge Elimination System (NPDES) Permit Program, define pollution
control technologies, establish effluent limitations, obtain information
through reporting and compliance inspections, and take enforcement actions
(both civil and criminal) when violations of the Act occur.
Inspection Authority
Under Section 402 of the Act, dischargers of pollutants are issued permits
that set specific limits and operating conditions to be met by the permittee.
Section 308 authorizes inspections and monitoring to determine whether
NPDES permit conditions are being met. The section provides for two
types of monitoring:
• Self-monitoring, where the facility must monitor itself
• EPA monitoring, which may consist of evaluating the self-
monitoring or conducting its own monitoring.
According to the Act, EPA may conduct an inspection wherever there is an
existing NPDES permit, or where a discharge exists or is likely to exist
and no permit has been issued.
State Program Authority
Much of the compliance with the NPDES program is monitored by the State.
Sections 308 and 402 of the Act provide for the transfer of Federal
program authority to States to conduct NPDES permit compliance monitoring.
EPA Regional Administrators and some State water pollution control agencies
have signed formal cooperative agreements that ensure timely, accurate
monitoring of compliance with permit conditions.
NPDES Inspection Manual171January 1988
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Chapter One
B RESPONSIBILITIES OF THE NPDES
INSPECTOR
The primary role of a NPDES inspector is to gather information that can
be used to determine compliance with permit conditions, applicable
regulations, and other requirements. The NPDES inspector also plays an
important role in enforcement case development and support, and in permit
development. To fulfill these roles, inspectors are required to know and
abide by legal requirements concerning inspections, procedures for
effective inspection and evidence collection, accepted safety practices,
and quality assurance standards.
Legal Responsibilities
Inspectors must conduct all inspection activities within the legal framework
established by the Act, including:
• Presenting proper credentials
• Presenting required notices
• Properly handling confidential business information.
Inspectors also must be familiar with the conditions of the specific
permit and with all applicable statutes and regulations.
Procedural Responsibilities
Inspectors must be familiar with general inspection procedures and evidence
collection techniques to ensure accurate inspections and to avoid endangering
potential legal proceedings on procedural grounds.
Inspection Procedures
Inspectors should observe standard procedures for conducting each inspection
element. Responsibilities are illustrated in Table 1-1, given at the end of
this section.
NPDES Inspection Manual373January 1988
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Chapter One Introduction
Evidence Collection
Inspectors must be familiar with general evidence-gathering techniques.
Because the Government's case in a civil or criminal prosecution depends
on the evidence they have gathered, inspectors must keep detailed records
of each inspection. These data will serve when preparing the inspection
report, determining the appropriate enforcement response, and giving
testimony in an enforcement case.
In particular, inspectors must know how to:
0 Substantiate facts with items of evidence, including samples,
photographs, document copies, statements from witnesses, and
personal observations
Evaluate what evidence is necessary (routine inspections)
Abide by chain-of-custody procedures
Collect and preserve evidence in a manner that will be
incontestable in legal proceedings
Write clear, objective, and informative inspection reports
Testify in court and administrative hearings.
Inspection procedures are discussed in detail in Chapter Two of this
manual.
Safety Responsibilities
The inspection of wastewater and other environmental pollution control
facilities always poses a certain degree of health and safety risk. To
avoid unnecessary risks, the inspector should be familiar with all safety
guidance and practices and should:
0 Use safety equipment in accordance with available guidance and
labeling instructions
0 Maintain safety equipment in good condition and proper working
order
0 Dress appropriately for the particular activity and wear
appropriate protective clothing
0 Use any safety equipment customary in the establishment being
inspected (e.g., hard hat or safety glasses).
Procedures to minimize risks during a facility site inspection are
discussed in Chapter Four of this manual. For any safety-related questions
not covered in this manual, consult the current approved safety manual
for greater detail.
NPDES Inspection Manual 1-4 January 1988
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uneIntroduction
Professional Responsibilities
Inspectors are expected to perform their duties with the highest degree
of professionalism. Procedures and requirements ensuring ethical actions
have been established through many years of Government inspection experience.
The procedures and standards of conduct listed below have evolved for the
protection of the individual and EPA, as well as industry.
o All investigations are to be conducted within the framework of the
United States Constitution and with due regard for individual
rights regardless of race, sex, creed, or National origin.
o Inspectors are to conduct themselves at all times in accordance
with the regulations prescribing employee responsibilities and
conduct.
o The facts of an investigation are to be developed and reported
completely, accurately, and objectively.
o In the course of an investigation, any act or failure to act
motivated by reason of private gain is illegal. Actions that
could be construed as such should be scrupulously avoided.
o A continuing effort should be made to improve professional
knowledge and technical skill in the investigative field.
Professional Attitude
The inspector is a representative of EPA and is often the initial or only
contact between EPA and the permittees. In dealing with facility repre-
sentatives and employees, inspectors must be professional, tactful, courteous,
and diplomatic. A firm but responsive attitude will encourage cooperation
and initiate good working relations. Inspectors should not speak derogatorily
of any product, manufacturer, or person.
Attire
Inspectors should dress appropriately, including wearing protective
clothing or equipment, for the activity in which they are engaged.
Gifts, Favors, Luncheons
Inspectors should not accept favors or benefits under circumstances that
might be construed as influencing the performance of governmental duties.
EPA regulations provide an exemption whereby an inspector could accept
food and refreshment of nominal value on infrequent occasions in the
ordinary course of a luncheon or dinner meeting or other meeting, or
during an inspection tour. Inspectors should use this exemption only
when absolutely necessary. Employees are not authorized to accept business
luncheons; they must pick up their own checks. (See page 20, U.S. EPA
Guidance on Ethics and Conflict of Interest, February 1984.)
NPDES Inspection Manual 1-5 January 1988
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Chapter One Introduction
Requests for Information
EPA has an "open-door" policy on releasing information to the public.
This policy is to make information concerning EPA and its work freely and
equally available to all interested individuals, groups, and organizations.
In fact, EPA employees have both a legal and traditional responsibility
for making useful educational and safety information available to the
public. This policy, however, does not extend to information about a
suspected violation, evidence of possible misconduct, or confidential
business information.
Quality Assurance Responsibilities
The inspector must assume primary responsibility for ensuring the quality
of compliance inspection data. While other organizational elements play
an important role in quality assurance, it is the inspector who must ensure
that all data introduced into an inspection file are complete, accurate,
and representative of existing conditions. To help the inspector meet
this responsibility, Regional Offices have established quality assurance
plans that identify individual responsibilities and document detailed
procedures.
The objective of a quality assurance plan is to establish standards that
will guarantee that inspection data meet the requirements of all users.
Many elements of quality assurance plans are incorporated directly into
the basic inspection procedures and may not be specifically identified
as quality assurance techniques.
The inspector must be aware that following established inspection
procedures is critical to the inspection program. These procedures have
been developed to reflect the following quality assurance elements:
0 Valid data collection
• Approved standard methods
• Control of service, equipment, and supplies
• Quality analytical techniques
• Standard data handling and reporting.
NPDES Inspection ManualT^6January
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Chapter One Introduction
Table 1-1
Responsibilities of the Inspector in the Inspection Process
The elements of the inspection process listed below are common to most
NPDES compliance inspections. While the emphasis given to each
element may vary among facilities, the inspector's procedural
responsibilities remain as listed.
Pre-Inspection Preparation. Ensure effective use of inspection
resources.
t Establish purpose and scope of inspection
• Review background information and EPA records, including
permit and permittee compliance file
• Contact appropriate staff personnel responsible for the
permittee: compliance personnel, pretreatment coordinator, etc,
• Develop plan for inspection
t Prepare documents and equipment
• Coordinate schedule with laboratory if samples are to be
collected
t Coordinate schedule with other appropriate regulatory
authorities
• Contact party responsible for sample transportation, for
packing/shipping requirements.
Entry. Establish legal entry to facility.
• Present official credentials
• Manage denial of entry if necessary.
Opening Conference. Orient facility officials to inspection plan.
• Discuss inspection objectives and scope
• Establish working relationship with facility officials.
Facility Inspection. Determine compliance with permit conditions;
collect evidence of violations.
Conduct visual inspection of facility
Review facility records
Inspect monitoring equipment and operations
Collect samples
Review laboratory records for QA/QC
Review laboratory procedures to verify use of approved methods
Document inspection activities.
NPDES Inspection Manual 1-7 January 1988
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Chapter One Introduction
Table 1-1
Responsibilities of the Inspector in the Inspection Process
(Continued)
Closing Conference. Conclude inspection.
• Collect missing or additional information
• Clarify questions with facility officials
0 Prepare necessary-receipts
• Review inspection findings and inform officials of follow-up
procedures
• Issue deficiency notice, if appropriate.
Inspection Report. Organize inspection findings into a useful,
objective evidence package.
• Complete NPDES Compliance Inspection Report form
0 Prepare narrative report, checklists, and documentary
information as appropriate.
NPOES Inspection Manual 1-8 January 1988
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Chapter One
C MULTIMEDIA CONCERNS IN NPDES
PERMITTING AND INSPECTIONS
The NPDES program has made significant progress in controlling point
source discharges to surface waters. This progress is measured indirectly,
by reduced loadings to surface waters, and directly, by improved water
quality. Nevertheless, a need for further improvement to address toxicity
problems exists. Effluent toxicity tests and ecological surveys completed
by EPA and the States indicate that further controls may be necessary.
In addition, NPDES effluent controls may result in transferring residuals
from surface waters to other media. This section summarizes additional
issues that merit the attention of NPDES program personnel now and in the
future.
Surface Water Discharges
As stated above, effluent toxicity tests and ecological surveys completed
by EPA and the States indicate that despite the progress that has been
made, further controls may be necessary to achieve the "fishable/swimmable"
goals of the CWA in certain receiving waters. To this end, EPA issued a
policy on the control of toxic pollutants (49 FR 9016) and a comprehensive
technical guidance document (Technical Support Document for Uater Quality-
based Toxics Control, September 1985). The Federal policy and the Technical
Support Document (TSD) both recognize that the NPDES program has, for the
most part, focused on a limited number of conventional, nonconventional,
and priority pollutants. Work conducted by EPA and the States indicates
that "nonconventional" pollutants, particularly nonpriority organic
pollutants, are a potentially large source of continued effluent toxicity.
The major organics industries discharge greater than one kilogram of
nonpriority hazardous constituents for each kilogram of priority
constituents. In some cases, the inspector and/or permit writer will be
able to identify readily the continued source of toxicity. However, in
more complex cases, the pollutant(s) of concern may not be identified
readily. The inspector should be aware that the pollutant(s) of concern
need not be identified to develop permit limitations, and the TSD does
provide recommended procedures for identifying these pollutant(s).
NPDES Inspection Manual175January 1988
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Chapter One . Introduction.
Identifying the specific pollutants of concern can help the inspector
focus the inspection plan and tailor any sampling activities. Rather
than conducting extensive analytical tests to identify the pollutant(s)
present in an effluent, the inspector or permit writer should first review
available information on the facility's product process and waste process
lines The review need not be limited to available NPDES information,
such as the Form 2C of the NPDES permit application; information on wastes
produced and discharged may be available from other sources including
information supplied to officials responsible for administering other
environmental programs, such as the Resource Conservation and Recovery
Act (RCRA).
Many NPDES regulated facilities are also subject to RCRA requirements.
RCRA regulates the generation, transportation, treatment, storage, and
disposal of hazardous wastes. However, it defers the control of hazardous
wastes to the CWA when those wastes are either directly discharged to
surface waters (the direct discharge exclusion) or indirectly discharged
to a wastewater treatment plant (the domestic sewage exclusion). Whereas
many of the 126 priority pollutants are also hazardous constituents, the
number of hazardous constituents (383) dwarfs the number of priority
pollutants. The discharge of these hazardous constituents should concern
the inspectors and operators of wastewater treatment plants.
Hazardous wastes discharged to wastewater treatment plants pass through
to surface waters unless incidentally removed in sludge, degraded, or
"lost" during the wastewater treatment process through volatilization or
exfiltration during treatment. The costs of hazardous waste management
using "traditional" storage, treatment and disposal methods are rising
significantly as facilities are beginning to comply with the 1984 RCRA
Amendments. Consequently, industrial facilities may increasingly use the
two previously mentioned exclusions as preferred disposal methods. NPDES
permit writers and inspectors may learn whether the facility conducts
RCRA regulated activities, and the nature of those activities, from State
and/or EPA authorities.
Another source of contaminated wastewaters is hazardous waste clean up
actions. Under the RCRA and the Comprehensive Environmental Response and
Compensation Liabilities Act (CERCLA), EPA, States, and private parties
are initiating clean ups of contaminated sites. Much of the waste found
at these sites is liquid, either leachate or contaminated ground water.
The treatment, and consequent discharge, of contaminated wastewaters from
these sources is expected to increase in the future. These wastes will
likely be complex mixtures, requiring a careful examination of their
composition to determine appropriate treatment techniques.
Intermedia Transfers Resulting From Wastewater Treatment
It has long been known that wastewater treatment results in the transfer
of residuals from wastewater effluents to sludges. Many different statutes
and regulations, including the CWA, are charged with management of these
sludges. Future NPDES permits will include sludge disposal limitations.
NPDES Inspection Manual 1-10 January 1988
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Chapter One Introduction
Many States already impose such requirements. NPDES inspectors will need
to become more familiar with the relationship between NPDES sludye
requirements and those imposed by other statutes and regulations,
particularly RCRA, and the Clean Air Act (CAA).
Air emissions from wastewater treatment units are under increasing
scrutiny. For organic chemical facilities, EPA is now considering
developing wastewater treatment controls which explicitly recognize that
treatment processes, such as air stripping, result in the transfer of
volatile organics from wastewater effluents to the air. EPA is also
considering air emissions from domestic wastewater treatment plants from
two perspectives: ambient air quality concerns and a concern for worker
health and safety. In another development, the 1984 RCRA amendments
provide for the control of air emissions from authorized RCRA treatment,
storage, and disposal facilities (TSDFs). As a result, wastewater
treatment facilities at RCRA TSDFs are now being investigated by RCRA
program personnel. Remedial actions may be required at some of these
facilities and the regulatory issue of emissions from wastewater treatment
facilities will be addressed.
POTWs receiving hazardous wastes by truck, rail, or dedicated pipeline
are subject to RCRA permit by rule requirements. Included among these
requirements is the provision that corrective action must be taken to
remedy any contamination which may have resulted from a release of
hazardous waste or hazardous constituents from solid waste management
units, such as surface impoundments, to the environment. For example, if
a POTW subject to these RCRA requirements contaminated groundwater through
leaching or exfiltration, the permittee might be required to investigate
the nature and extent of those releases and, where appropriate, implement
corrective measures. Guidance on the nature of these requirements, and
how they might affect POTWs, is now being developed.
Summary
The above discussion summarizes coming issues in the NPDES program from a
crossmedia perspective. It is apparent from this discussion that several
challenges face NPDES inspectors in the future. These challenges represent
a developing concept in environmental program management, the "full
facility" approach, which requires an understanding of all the potential
environmental impacts of a facility's operations and a concommittant
attempt to better coordinate regulatory programs to reduce environmental
risks. Such an approach can be used during NPDES inspections. If concerns
are identified which do not relate to NPDES, the inspector should document
the concern and refer it to the proper agency for investigation. For example,
worker related concerns should be relayed to the Occupational Safety and
Health Administration (OSHA). Any questions on who is the responsible
agency should be verified.
NPDES Inspection Manual 1-11 January 1988
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Chapter Two
INSPECTION PROCEDURES
Contents Page
A Pre-Inspectlon Preparation
Review of Facility Background Information 2-1
General Facility Information 2-1
Requirements, Regulations, and Limitations 2-2
Facility Compliance and Enforcement History 2-2
Pollution Control and Treatment Systems 2-2
Pretreatment Information 2-3
Sources of Facility Background Information 2-3
Development of an Inspection Plan 2-4
Notification of the Facility 2-5
State Notification of Federal Inspection 2-5
Equipment Preparation 2-5
B Entry
Entry Procedures 2-11
Authority 2-11
Arrival 2-11
Credenti al s 2-11
Consent 2-12
Waivers, Releases, and Sign-In Loys 2-12
Problems With Entry or Consent 2-13
Denial of Entry 2-13
Important Considerations 2-13
Withdrawal of Consent During Inspection 2-14
Denial of Access to Some Areas of the Facility 2-14
Warrants 2-14
NPDES Inspection Manual 2^\ January 1988
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Chapter Two Contents
C Opening Conference
Considerations 2-15
Inspection Objectives 2-15
Order of Inspection 2-15
Meeting Schedules 2-15
List of Records 2-15
Accompaniment 2-16
Permit Verification 2-16
Safety Requirements 2-16
Closing Conference 2-16
New Requirements 2-16
Split Samples 2-16
Photographs 2-16
D Documentati on
Inspector's Field Notebook 2-19
Inspection Notes 2-19
Samples 2-20
Statements 2-20
Procedures and Considerations 2-20
Photographs 2-21
Equi pment 2-22
Scale, Location, and Direction 2-22
Safety 2-22
Documenting Photographs 2-22
Video Tapes 2-23
Drawings and Maps 2-23
Printed Matter 2-23
Mechanical Recordings 2-24
Copies of Records 2-24
Obtaining Copies of Necessary Records 2-24
Identification Procedures 2-25
General Considerations 2-25
Routine Records 2-25
Confidential Information 2-26
Disclosure of Official Information 2-26
Trade Secrets and Confidential Business Information 2-26
Handling Confidential Business Information 2-26
E Closing Conference
Precautions and Guidelines 2-29
Deficiency Notice 2-29
F Inspection Report
Objective of the NPDES Inspection Report 2-33
Elements of a Report 2-34
NPDES Compliance Inspection Report Form 2-34
Supplementary Narrative Information 2-34
Copies of Completed Checklists 2-35
Documentary Support 2-35
The Permit Compliance System (PCS) 2-35
NPDES Inspection Manual 2-ii January 1988
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Chapter Two Contents
List of Tables
2-1 NPDES-Related Statutes and Regulations 2-7
List of Figures
2-1 Sample 308 Letter 2-9
2-2 EPA Deficiency Notice Form 2-31
2-3 NPDES Compliance Inspection Report Form 2-37
NPDES Inspection Manual 2-iii January 1988
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Chapter Two
A PRE-INSPECTION PREPARATION
Pre-planning is necessary to ensure that the inspection is focused properly
and is conducted smoothly and efficiently. It involves:
Review of facility background information
Development of an inspection plan
Notification of the facility
State notification of Federal inspection
Equipment preparation.
Review of Facility Background Information
Collection and analysis of available background information on the candi-
date facility are essential to the effective planning and overall success
of a compliance inspection. Materials obtained from files of Federal,
State, and local agencies, technical libraries, and other information
sources will enable inspectors to familiarize themselves with facility
operations; conduct a timely inspection; minimize inconvenience to the
facility by not requesting data previously provided to the Federal,
State, and/or local agencies; conduct a thorough and efficient inspection;
clarify technical and legal issues before entry; and develop a sound and
factual inspection report. The types of information that may be available
for review are listed below. The inspector must determine the amount of
background information necessary for the inspection and in collecting
this information should focus on the characteristics unique to the per-
mittee: design, historical practices, legal requirements, etc.
General Facility Information
• Maps showing facility location, wastewater discharge pipes,
and geographic features
• Names, titles, and telephone numbers of responsible facility
officials
• Any special entry requirements
NPDES Inspection Manual 2-1 January 1988
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Chapter Two Inspection Procedures
Nature of processing operations and wastewater
Production levels—past, present, and future
Hydrological data
Geology/hydrogeology of the area
Changes in facility conditions since previous inspection/permit
application
• Available aerial photographs.
Requirements, Regulations, and Limitations
• Copies of Federal, State, and local existing permits, regulations,
and requirements
• Restrictions placed on permittee discharges in the form of standards
and compliance schedules
• Monitoring and reporting requirements and available monitoring
stations
• Special exemptions and waivers, if any
• Receiving stream water quality standards
• Information concerning air, solid, and hazardous waste treatment
and disposal.
Facility Compliance and Enforcement History
• Correspondence among facility, local, State, and Federal agencies
• Complaints and reports, follow-up studies, findings, and remedial
action
• Documentation on past compliance violations, exceedences,
status of requested regulatory corrective action, if any
• Status of current and pending litigation against facility
• Self-monitoring data and reports
• Previous EPA, State, or consultant studies and reports
• Previous deficiency notices issued to facility
• Laboratory capabilities and analytical methods used by the
facility
• Previous Discharge Monitoring Report (DMR) - Quality Assurance
(QA) files and reports.
Pollution Control and Treatment Systems
0 Description and design data for pollution control system and
process operation
• Sources and characterization of discharge
• Type and amount of wastes discharged
• Spill prevention contingency plans
0 Available bypasses or diversions and spill containment
facilities
• Pollution control units, treatment methods, and monitoring systems.
NPDES Inspection Manual 2-2 January 1988
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Chapter Two Inspection Procedures
Pretreatment Information
• Information concerning compliance schedule to install pretreatment
technologies (industrial facilities) or develop a pretreatment
program [Publicly Owned Treatment Works (POTWs)]
• Pretreatment reports as required by the General Pretreatment
Regulations, regional, State, or local requirements
• Information concerning industrial discharges to POTWs, such as:
- Industrial monitoring and reporting requirements
- POTW monitoring and inspection program
- Waste contribution to the POTW
- Compliance status of industry with pretreatment requirements
- POTW enforcement initiatives.
Sources of Facility Background Information
Other Inspectors. Inspectors who have visited the facility for NPDES or
other regulatory programs may have information on the facility.
Laws and Regulations. The Clean Water Act (CWA) and related regulations
establish procedures, controls, and other requirements applicable to a
facility. In addition, state laws and regulations, and sometimes even
local ordinances, are applicable to the same facility. [See Table 2-1
for applicable National Pollutant Discharge Elimination System (NPDES)
statutes and regulations.]
Permits and Permit Applications. Permits provide information on the
limitations, requirements, and restrictions applicable to discharges;
compliance schedules; and monitoring, analytical, and reporting
requirements. Applications provide technical information on facility
size, layout, and location of pollutant sources; treatment and control
practices; contingency plans and emergency procedures; and pollutant
characterization—types, amounts, and points/locations of discharge.
Applications for air, solid, and hazardous waste treatment and disposal
permits may provide additional information to the inspector that is not
available elsewhere.
Regional and State Files and Contacts. Files or contacts often can
provide correspondence; facility self-monitoring data; inspection, Quarterly
Noncompliance Report (QNCR), and DMR QA reports; and permits and permit
applications applicable to individual facilities. They can provide
compliance, enforcement, and litigation history; special exemptions and
waivers applied for and granted or denied; citizen complaints and action
taken; process operational problems/solutions; pollution problems/solutions;
laboratory capabilities or inabilities; and other proposed or historical
remedial actions. This information can provide design and operation data,
recommendations for process controls, identification of pollutant sources,
treatment/control systems improvement, and remedial measures.
Technical Reports, Documents, and References. These information sources
provide generic information on waste loads and characterization, industrial
process operations, and pertinent specific data on available treatment/control
NPDES Inspection Manual 2-3 January 1988
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Chapter^ Two Inspection Procedure^
techniques, such as their advantages or disadvantages and limits of
application and pollutant removal efficiencies. Such sources include
Development Documents for Effluent Standards and Guidelines.
Other Statutory Requirements. Facility files maintained pursuant to
other statutes [e.g., Toxic Substances Control Act (TSCA); Resource
Conservation and Recovery Act (RCRA); Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA); Federal Insecticide, Fungicide
and Rodenticide Act (FIFRA); Clean Air Act (CAA), etc.] also contain
information useful to the NPDES inspection.
Development of an Inspection Plan
Plans are helpful tools in organizing and conducting compliance inspections,
A plan is, therefore, recommended to effectively conduct a compliance in-
spection. After reviewing the available background information, a com-
prehensive plan is prepared to define inspection objectives; tasks and
procedures; resources required to fulfill the objectives; the inspection
schedule; and when findings and conclusions on the work will be reported.
At least the following items need to be considered:
• Objectives
- What is the purpose of the inspection?
- What is to be accomplished?
• Tasks
- What tasks are to be conducted?
- What information must be collected?
• Procedures
- What procedures are to be used?
- Will the inspection require special procedures?
• Resources
- What personnel will be required?
- What equipment will be required?
- What records will be reviewed?
0 Schedule
- What will be the time requirements and order of inspection
activities?
- What will be the milestones?
• Coordination
- What coordination with laboratories or other regulatory
agencies is required?
NPDES Inspection Manual?3January 1988
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Chapter Two Inspection Procedures
An outline of inspection objectives, meetings to be held, and records that
will be reviewed can be prepared and presented to the facility officials
during the opening conference.
Notification of the Facility
With regard to the EPA administered NPDES program, the permittee sometimes
is notified by a "308 Letter" that the facility is scheduled for an
inspection. (Figure 2-1, presented at the end of this section, is an
example of a typical 308 Letter.) The signature authority for a 308
Letter may be delegated to a section chief. The 308 Letter advises the
permittee that an inspection is imminent and usually requests information
regarding on-site safety regulations to avoid problems concerning safety
equipment at the time of inspection. The inspector may wish to facilitate
the inspection process by suggesting that the permittee send general
information to the inspector before the site visit. This information may
include such items as names, addresses, and updated process information.
The 308 Letter may specify the exact date of inspection, if coordination
with the permittee is required. The 308 Letter also is used to inform
the permittee of the right to assert a claim of confidentiality. Depending
on the type of inspection, the permittee may be notified by telephone
that an inspection is imminent. However, inspections are usually done
without any pre-notification of the exact date.
Notification is not recommended when illegal discharges or emissions or
improper records are suspected. The concern that physical conditions may
be altered before the inspection or that records will be destroyed
justifies an unannounced inspection. A written notification including
information on the right to assert a claim of confidentiality can be
presented at the time of the unannounced inspection.
State Notification of Federal Inspection
The inspector must be certain that the appropriate State regulatory
agency is notified in a timely manner of inspections to be conducted in
its jurisdiction. The State should be notified of all Federal inspections
unless disclosing inspection information would jeopardize an unannounced
inspection.
Equipment Preparation
Part of the pre-inspection process involves obtaining and preparing
inspection equipment. The type of equipment may vary according to the
facility inspected and the type of inspection. All equipment must be
checked, calibrated, and tested before use. The inspector also must ensure
NPDES Inspection ManualttJanuary 1988
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Chapter Two Inspection Procedures
that all materials necessary to complete an inspection are taken to the
inspection site. The inspector is responsible for maintaining the equipment
properly in accordance with operating instructions.
Safety equipment and procedures required for a facility will be based on
the response to the notification or 308 Letter and standard safety
procedures. Safety requirements must be met, not only for safety reasons,
but to ensure that the inspector is not denied entry to the facility or
parts of it.
Photocopies of appropriate checklists to be used during the inspection
should be obtained during the pre-inspection preparation.
NPDES Inspection ManualttJanuary 1988
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Chapter Two
Inspection Procedures
Table 2-1
NPDES-Related Statutes and Regulations
Topic
Reference
Inspection Authority
Self-Monitoring and
Recordkeeping Authority
Confidential Information
Emergency Authority
Employee Protection
Permits
EPA Permitting Procedures
Technical Requirements
Best Management Practices (BMP)
Spill Prevention Control and
Countermeasure Plan (SPCC)
Waivers
Effluent Guidelines
Pretreatment Standards
CWA1
§308
§308
§308(5)
§504
§507
§402
§402
40 CFR2
122.41(i),a
123.26a
122.41(h), (j),
and (l).a 122.48a
2.201, 2.215..
2.302, 122.1°
123.27a
122,b 123.25a
124
§§301,304,307 129,a 133,a 136a
§304(e) 125
§311 112
§301
§304
§§307, 402
125, 230
400-4603
125, 403, and
400-4603
1 Clean Water Act
2 Code of Federal Regulations, Revised as of July 1, 1986
a Applies to State programs
b Partially applies to State programs
NPDES Inspection Manual
2-7
January 1988
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Chaoter Two Inspection Procedures
Certified Mail - Return Receipt Requested
Date
Dear Sir:
Pursuant to the authority contained in Section 308 of the Clean
Water Act (33 U.S.C. 1251 et seq.), representatives of the U.S.
Environmental Protection Agency (EPA), or a contractor retained by
EPA, shall conduct, within the next year, a compliance monitoring
inspection of your operations, including associated waste treatment
and/or discharge facilities located at (site of inspection). This
inspection will ascertain the degree of compliance with the
requirements of the National Pollutant Discharge Elimination System
(NPDES) permit issued to your organization.
Our representatives may observe your process operations, inspect your
monitoring and laboratory equipment and methods, collect samples,
examine appropriate records, and will be concerned with related
matters.
In order to facilitate easy access to the plant site, please provide
the name of the responsible facility official who can be contacted
upon arrival at the plant. Additionally, we would appreciate
receiving a list of the safety equipment you would recommend that our
representatives have in their possession in order to enter and
conduct the inspection safely. Please provide the information
requested within 14 days of receipt of this letter.
If you have any questions concerning this inspection, please call
(appropriate designated official).
Sincerely,
Director
Water Management Division
Figure 2-1
Sample 308 Letter
NPDES Inspection Manual 2-9 January 1988
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Chapter Two
B ENTRY
Entry Procedures
Authority
The basic authority for entry into a wastewater facility is §308(a)(4)(B)
of the CWA which states:
the Administrator or his authorized representative, upon
presentation of his credentials shall have a right of entry
to, upon, or through any premises in which an effluent
source is located or in which any records are required to be
maintained . . . and may at reasonable times have access
to and copy any records, inspect any monitoring equipment
or method . . . and sample any effluents which the owner or
operator of such source is required to sample.
Arrival
Arrival at the facility should occur during normal working hours. The
facility owner or agent in charge should be located as soon as the
inspector arrives on the premises.
Credentials
When the proper facility officials have been located, the inspector must
introduce himself or herself as an EPA/State inspector and present the
proper EPA credentials. These credentials indicate that the holder is a
lawful representative of the regulatory agency and is authorized to
perform NPDES inspections. The credentials must be presented whether or
not identification is requested.
After facility officials have reviewed the credentials, they may telephone
the appropriate State or EPA Regional Office for verification of the
inspector's identification. Credentials should never leave the sight of
the inspector.
NPDES Inspection Manual 2-11 January 1988
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Chapter Two Inspection Procedures^
Consent
Consent to inspect the premises must be given by the owner or operator at
the time of the inspection. As long as the inspector is allowed to enter,
entry is considered voluntary and consentual, unless the inspector is
expressly told to leave the premises. Expressed consent is not necessary;
absence of an expressed denial constitutes consent.
Reluctance to Give Consent. The receptiveness of facility officials
toward inspectors is likely to vary among facilities. Most inspections
will proceed without difficulty. If consent to enter is flatly denied,
the inspector should follow denial of entry procedures. In other cases,
officials may be reluctant to give entry consent because of misunderstood
responsibilities, inconvenience to a firm's schedule, or other reasons
that may be overcome by diplomacy and discussion.
Whenever there is a difficulty in gaining consent to enter, inspectors
should tactfully probe the reasons and work with officials to overcome the
problems. Care should be taken, however, to avoid threats of any kind,
inflammatory discussions, or deepening of misunderstandings. If the
situation is beyond the authority or ability of the inspector to manage,
the regulatory office should be contacted for guidance.
Uncredentialed Persons Accompanying an Inspector. The consent of the
owner or agent in charge must be obtained for persons accompanying an
inspector to enter a site if they do not have specific authorization.
If consent is not given, these persons may not enter the premises. If
consent is given, they may not view confidential business information
unless officially authorized for access.
Waivers, Releases, and Sign-In Logs
When the facility provides a blank sign-in sheet, log, or visitor register,
it is acceptable for inspectors to sign it. However, EPA employees must
not sign any type of "waiver" or "visitor release" that would relieve the
facility of responsibility for injury or that would limit the rights of
EPA to use data obtained from the facility. The inspector must not agree
to any such unwarranted, restrictive conditions.
If such a waiver or release is presented, the inspectors should politely
explain that they cannot sign and request a blank sign-in sheet. If the
inspectors are refused entry because they do not sign the release, they
should leave and immediately report all pertinent facts to the appropriate
supervisory and/or legal staff. All events surrounding the refused entry
should be fully documented. Problems should be discussed cordially and
professionally. Facility officials must not be subjected to intimidation
by the Federal/State inspectors.
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Chapter Two Inspection Procedures
Problems With Entry or Consent
Because inspections may be considered adversarial proceedings, the legal
authority, techniques, and competency of inspectors may be challenged.
Facility officials also may display antagonism toward EPA personnel. In
all cases, inspectors must cordially explain the authorities and reasons
for the protocols followed. If explanations are not satisfactory or
disagreements are irresolvable, the inspectors should leave and obtain
further direction from the appropriate EPA supervisory or legal staff.
Professionalism and politeness must prevail at all times.
Denial of Entry
If an inspector is refused entry into a facility for the purpose of an
inspection under the CWA, certain procedural steps must be followed. The
procedures have been developed in accordance with the 1978 U.S. Supreme
Court decision in Marshal v. Barlow's, Inc.
t Ensure that all credentials and notices are presented properly
to the facility owner or agent in charge.
• If entry is not granted, ask why. Tactfully probe the reason for
the denial to see if obstacles (such as misunderstandings) can be
cleared. If resolution is beyond the authority of the inspector,
he or she may suggest that the officials seek advice from their
attorneys to clarify EPA's inspection authority under Section
308 of the CWA.
t If entry is still denied, the inspector should withdraw from the
premises and contact his or her supervisor. The supervisor will
confer with attorneys to discuss the desirability of obtaining an
administrative warrant.
• All observations pertaining to the denial are to be carefully noted
in the field notebook. Include such information as the facility
name and exact address, name and title of person(s) approached,
authority of person(s) who refused entry, date and time of
denial, detailed reasons for denial, facility appearance, and
any reasonable suspicions that refusal was based on a desire to
cover up regulatory violations. All such information will be
important should a warrant be sought.
Important Considerations
• Under no circumstances should the inspector discuss potential
penalties or do anything that may be construed as coercive or
threatening.
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Chapter Two Inspection Procedure^
t Inspectors should use discretion and avoid potentially
threatening or inflammatory situations. If a threatening
confrontation occurs, the inspector should document it and then
report it immediately to the staff attorney. If feasible,
statements from witnesses should be obtained and included in the
documentation.
Withdrawal of Consent During Inspection
If the facility agent in charge asks the inspector to leave the premises
after the inspection has begun, the inspector should leave as quickly as
possible following the procedures above for denial of entry. All activities
and evidence obtained before the withdrawal of consent are valid. The
inspector should ensure that all personal and government equipment is
removed from the facility.
Denial of Access to Some Areas of the Facility
If, during the course of inspection, access to some parts of the facility
is denied, the inspector should make a notation of the circumstances
surrounding the denial of access and of the portion of the inspection
that could not be completed. He or she then should proceed with the rest
of the inspection. After leaving the facility, the inspector should
contact his or her supervisor and staff attorney at the Regional Office
to determine whether a warrant should be obtained to complete the inspection,
Warrants
The inspector may be instructed by EPA attorneys, under certain circum-
stances, to conduct an inspection under search warrant. A warrant is
a judicial authorization for appropriate persons to enter specifically
described locations to inspect specific functions. A pre-inspection
warrant possibly could be obtained where there is reason to believe that
entry will be denied when the inspector arrives at the facility or when
the inspector anticipates violations that could be hidden during the time
required to obtain a search warrant.
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Chapter Two
C OPENING CONFERENCE
Once credentials have been presented and legal entry has been established,
the inspector can proceed to outline inspection plans with facility officials.
At the opening conference, the inspector provides names of the inspectors,
the purpose of the inspection, authorities under which the inspection is being
conducted, and procedures to be followed. The Agency encourages cooperation
between the inspectors and the facility officials in order to facilitate
assignments and ensure the success of the inspection.
Considerations
Inspect i on Objecti ves
An outline of inspection objectives will inform facility officials of the
purpose and scope of the inspection and may help avoid misunderstandings.
Order of Inspection
A discussion of the order in which the inspection will be conducted will
help eliminate wasted time by allowing officials time to make records
available and start up intermittent operations.
Meeting Schedules
A schedule of meetings with key personnel will allow facility officials
adequate time to spend with the inspector.
List of Records
A list of facility records that will need to be reviewed as part of the
inspection should be provided to facility officials. This will allow the
officials adequate time to gather the records and make them available for
the inspector.
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Chapter Two Inspection Procedure!
Accompaniment
It is important that a facility official accompany the inspector during
the inspection not only to answer questions and describe the plant and
its principal operating characteristics, but also for safety and liability
considerations. Discussion of such needs with facility officials will
provide them the opportunity to allocate personnel for this purpose.
Permit Verification
The inspector should verify pertinent information included in the permit,
such as name and address,'receiving waters and discharge points.
Safety Requirements
The inspector should reaffirm which Occupational Safety and Health
Administration (OSHA) and facility safety regulations will be involved in
the inspection, and should determine if preparations were adequate.
Closing Conference
A post-inspection meeting should be scheduled with appropriate officials
to provide a final opportunity to gather information, answer questions,
present findings and deficiencies, and complete administrative duties.
New Requirements
The inspector should discuss and answer questions pertaining to any new
rules and regulations that might affect the facility. If the inspector
is aware of proposed rules that might affect the facility, he or she may
wish to encourage facility officials to obtain a copy.
Split Samples
Facility officials should be informed during the opening conference of
their right to receive a split of any physical sample collected for
laboratory analysis. Officials should indicate at this point their
desire to receive split samples so that arrangements can be made to
secure the samples during inspection.
Photographs
Photographs can be used to prepare a more thorough and accurate inspection
report, as evidence in enforcement proceedings, and to explain better
conditions found at the plant. The facility officials, however, may
object to the use of cameras on their property. If a mutually acceptable
solution cannot be reached and photographs are considered essential to
the inspection, EPA supervisory and legal staff should be contacted for
advice.
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Chapter Two Inspection Procedures
Facility personnel also may request that any photographs taken during the
visit be considered confidential. EPA is obliged to comply with this
request pending further legal determination. Facility officials may
refuse permission to take photographs unless they can see the finished
print. Self-developing film, although of lower quality, is useful in
certain situations. Duplicate photographs (one for the inspector and the
other for the company) should also satisfy this need.
NPDES Inspection Manual 2-17 January 1988
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Chapter Two
D DOCUMENTATION
Providing strong documentary support of discrepancies uncovered in an
inspection is an inspector's basic responsibility. Documentation serves
to "freeze" the actual conditions existing at the time of inspection so
that evidence may be examined objectively by compliance personnel.
Documentation is a general term referring to all print and mechanical
media produced, copied, or taken by an inspector to provide evidence of
suspected violations. Some types are the field notebook, statements,
photographs, drawings, maps, printed matter, mechanical recordings,
and copies of records.
Inspector s Field Notebook
The core of all documentation relating to an inspection is the field
notebook, which provides accurate and inclusive documentation of all
inspection activities. A bound notebook should be used and entries should
be made in permanent ink. The notebook will form the basis for written
reports and should contain only facts and pertinent observations.
Language should be objective, factual, and free of personal feelings or
terminology that might prove inappropriate. Notebooks become an important
part of the evidence package and can be entered in court. The field
notebook is a part of EPA's files and is not to be considered the inspector's
personal record. Notebooks are held indefinitely pending disposition
instructions.
Inspection Notes
Since an inspector may be called to testify in an enforcement proceeding,
it is imperative that each inspector keep detailed records of inspections,
investigations, samples collected, and related inspection functions.
Notes taken by the inspector(s) and completed checklists can be stapled
in the field notebook. Types of information that should be entered into
the field notebook include:
NPDES Inspection Manual 2-19 January 1988
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Chapter Two Inspection Procedures^
Observations. All conditions, practices, and other observations that
will be useful in preparing the inspection report or that will validate
evidence should be recorded.
Documents and Photographs. All documents taken or prepared by the inspector
such as the completed checklists for the inspection report should be
noted and related to specific inspection activities. (Photographs taken
at a sampling site should be listed and described.)
Unusual Conditions and Problems. Unusual conditions and problems should
be noted and described in detail.
General Information. Names and titles of facility personnel and the
activities they perform should be listed along with statements they have
made and other general information. Weather condition should be recorded.
Information about a facility's recordkeeping procedures may be useful in
later inspections.
Samples
Samples are the evidence most frequently gathered by inspectors. For the
analysis of a sample to be admissible as evidence, a logical and documented
connection must be shown between samples taken and analytical results
reported. This connection is shown by using a chain-of-custody system that
identifies and accompanies a sample between the time it is collected and
the time it is analyzed. Sampling techniques and procedures are discussed
in detail in Chapter Five, "Sampling."
Statements
Inspectors can obtain a formal statement from a person who has personal ,
firsthand knowledge of facts pertinent to a potential violation. This
statement of facts is signed and dated by the person who can testify to
the facts in court and it may be admissible as evidence.
The principal objective of obtaining a statement is to record in writing,
clearly and concisely, relevant factual information so that it can be used
to document an alleged violation.
Procedures and Considerations
• Determine the need for a statement. Will it provide useful
information? Is the person making the statement qualified
to do so by personal knowledge?
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S Inspection ManualttfQJanuary
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Chapter Two Inspection Procedures
• Ascertain all the facts. Make sure all information is factual
and firsthand. Record those that are relevant and that the
person can verify in court. Avoid taking statements that cannot
be personally verified.
• In preparing a statement, use simple narrative style; avoid
stilted language.
- Narrate the facts in the words of the person making the
statement.
- Use the first-person singular ("I am manager of . . .").
- Present the facts in chronological order (unless the situation
calls for another arrangement).
• Positively identify the person (name, address, position).
• Show why the person is qualified to make the statement.
t Present the pertinent facts.
• Have the person read the statement and make any necessary
corrections before signing. If necessary, read the statement
to the person in the presence of a witness.
- All mistakes that are corrected must be initialed by the
person making the statement.
• Ask the person making the statement to write a brief concluding
paragraph indicating that he or she read and understood the
statement. This safeguard will counter a later claim that the
person did not know what he or she was signing.
• Have the person making the statement sign it.
• If he or she refuses to sign the statement, elicit an acknowledg-
ment that it is true and correct. Ask for a statement in his or
her own hand ("I have read this statement and it is true, but I am
not signing it because . . ."). Failing that, declare at the
bottom of the statement that the facts were recorded as revealed
and that the person read the statement and avowed it to be true.
Attempt to have any witness to the statement sign the statement
including witness1 name and address.
• Provide a copy of the statement to the signer if requested.
Photographs
The documentary value of photographs ranks high as admissible evidence.
Clear photographs of relevant subjects provide an objective record of
conditions at the time of inspection. If possible, keep "sensitive"
buildings or operations out of the photographed background.
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Chapter Two Inspection Procedures
When a situation dictates the use of photographs, the inspector should
obtain the permittee's approval before taking them. The inspector should
be tactful in handling any concerns or objections a permittee may have
about the use of a camera. In some cases, the inspector may explain to
the permittee's representative that wastestreams, receiving waters, and
wastewater treatment facilities are public information, not trade secrets.
In the event the permittee's representative still refuses to allow photo-
graphs and the inspector believes the photographs will have a substantial
impact on future enforcement proceedings, Regional enforcement attorneys
should be consulted for further instructions. At all times, the inspector
is to avoid confrontations that might jeopardize the completion of the
inspection. [Photographs always may be taken from areas of public access
(e.g., across a stream, from a parking lot, etc.).]
Equipment
A single-lens reflex camera should be used whenever one is available. This
type of camera will take high-quality photographs, enable the inspector
to use a variety of film speeds, and allow the use of appropriate lenses.
Fully automatic 35-mm and pocket cameras can also be used for routine
inspections to record the conditions of the facility during the inspection.
All photographs should be made with color print film because additional
equipment, such as a projector and screen, is not needed to review them.
Also, the negatives from color print film are easily duplicated and the
prints can be enlarged and distributed as needed.
Scale, Location, and Direction
It is sometimes useful to photograph a subject from a point that will
indicate the location and direction of the subject. The addition of an
object of known size (e.g., a person or an auto) will help indicate the
approximate size of the subject.
Safety
In areas where there is a danger of explosion, flash photographs should
not be taken. If there is a danger of electrical shock, photographs
should be taken from a distance known to be safe.
Documenting Photographs
Photographs taken during an inspection are used to supplement the testimony
of the inspector as a witness during a court proceeding. The photographs
are not intended to refute testimony but rather to aid the witness in
recalling actual conditions on-site.
A photographic log should be maintained in the inspector's field notebook
for all photographs taken during an inspection; the entries should be
made at the time the photograph is taken. These entries are to be
numerically identified so that, after the film is developed, the prints
NPUES Inspection Manual 2-22 January 19'8'S
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Chapter Two Inspection Procedures
can be serially numbered to correspond with the logbook descriptions and,
if necessary, pertinent information can be easily transferred to the back
of the photograph. The log entries should include:
Name and signature of the photographer and witness
Time of day, weather conditions
Date
Location
Brief description of each subject being photographed.
Some Regions use special stick-on labels to document photographs. These
are useful only if they are prepared objectively and are completely filled
in.
Video Tapes
Video tapes can provide an objective means of documenting subjects of
interest in an inspection. As with any photographed site or equipment,
permission from the permittee to produce a video tape should be obtained,
and the same precautions as those for photographs (previous section)
should be taken for sensitive material. Additionally, sound videos may
be produced whereby a narrative to the tape can quickly record much of
the information needed to complete an inspection report. Written notes
should be prepared during the site visit as a backup to the video tape
in case mechanical problems occur with the recording. If necessary,
color photographs can be made later by stopping the televised video at
frames of interest and photographing the picture.
Drawings and Maps
Schematic drawings, maps, charts, and other graphic records can be useful
in supporting violation documentation. They can provide graphic clarifi-
cation of site location relative to the overall facility, relative height
and size of objects, and other information which, in combination with
samples, photographs, and other documentation, can produce an accurate,
complete evidence package.
Drawings and maps should be simple and free of extraneous details. Basic
measurements and compass points should be included to provide a scale for
interpretation. Drawings and maps should be identified by source and be
dated.
Printed Matter
Brochures, literature, labels, and other printed matter may provide
important information regarding a facility's conditions and operations.
NPDES Inspection Manual2-23January 1988
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Chapter Two Inspection Procedures
This materials may be collected as documentation if, in the inspector's
judgment, they are relevant. All printed matter should be identified
with date, inspector's initials, and origin.
Mechanical Recordings
Records produced electronically or by mechanical apparatus can be entered
as evidence. Charts, graphs, and other "hard copy" documents should be
treated as documentation and handled accordingly.
Copies of Records
Records and files may be stored in a variety of information retrieval
systems, including written or printed materials, computer or electronic
systems, or visual systems such as microfilm and microfiche.
Obtaining Copies of Necessary Records
When copies of records are necessary for an inspection report, storage
and retrieval methods must be considered.
• Written or printed records generally can be photocopied on-site.
Portable photocopy machines may be available to inspectors through
the Regional Office. When necessary, however, inspectors are
authorized to pay a facility a "reasonable" price for the use of
facility copying equipment.
- At a minimum, all copies made for or by the inspector should
be initialed and dated for identification purposes. (See
identification details below.)
- When photocopying is impossible or impractical, closeup
photographs may be taken to provide suitable copies.
• Computer or electronic records may require the generation of
"hard" copies for inspection purposes. Arrangements should be
made during the opening conference, if possible, for these copies.
- Photographs of computer screens possibly may provide adequate
copies of records if other means are impossible.
t
Visual systems (microfilm, microfiche) may have photocopying
capacity built into the viewing machine, which can be used to
generate copies. Photographs of the viewing screen may provide
adequate copies if hard copies cannot be generated.
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Chapter Two Inspection Procedures
Identification Procedures
Immediate and adequate identification of records reviewed is essential to
ensure the identification of records throughout the EPA custody process
and their admissibility in court. When inspectors are called to testify.
they must be able to identify positively each particular document and
state its source and the reason for its collection.
Initial, date, number, and enter in the facility's name on each record, and
log these items in the field notebook.
Initialing/Dating. Each inspector should develop a unique system for
initialing (or coding) and dating records and copies of records so that
he or she can easily verify their validity. This can be done by initialing
each document in a similar position, or by another method, at the time of
collection. Both the original and copy should be initialed. All record
identification notations should be made on the back of the document. The
inspector must be able to identify positively that he or she so marked
the document.
Numbering. Each document or set of documents substantiating a suspected
violation(s) should be assigned an identifying number unique to that
document. The number should be recorded on each document and in the
field notebook.
Logging. Documents obtained during the inspection should be entered in
the field notebook by a logging or coding system. The system should
include the identifying number, date, and other relevant information:
• The reason for copying the material (i.e., the nature of the
suspected violation or discrepancy)
• The source of the record (i.e., type of file, individual who
supplied record)
• The manner of collection (i.e., photocopy, other arrangements).
General Considerations
• Originals must be returned to the proper person or to their
correct location
t Related records should be grouped together
• Confidential business records should be handled according to the
special confidential provisions discussed below.
Routine Records
The inspector may find it convenient to make copies of some records, such
as laboratory analysis sheets and data summaries, to refresh his or her
memory when preparing the inspection report. It is not always necessary
to follow the formal identification and logging requirements when such
records are obtained for general information purposes or to aid in the
preparation of routine inspection reports.
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Chapter Two Inspection Procedures
Confidential Information
Disclosure of Official Information
Inspectors may give general information about EPA programs and activities
and describe what they are doing, but they should be cautious about
divulging specific information regarding an inspection. It is permissible
to discuss with the permittee's representative deficiencies encountered
during an evaluation of self-monitoring procedures and the action required
to correct these deficiencies. However, it is not advisable to discuss
information collected during the course of an inspection that may indicate
the occurrence of a criminal or civil violation. Therefore, when an in-
spector has reason to believe that an enforcement action may be required,
no information should be disclosed before consulting with the attorney in
the Regional Office. Caution should be exercised in disclosing findings
or speculating on the type of action EPA may choose to take.
Trade Secrets and Confidential Business Information
Trade secrets and confidential business information are protected from
public disclosure by Section 308(b)(2) of the CWA. The type of information
that may be considered confidential business information is defined in
Title 40, Code of Federal Regulations, Part 2 (40 CFR Part 2).
Section 308(a)(4) of the CWA states that an inspector may sample an
effluent, request information, have access to the location of the effluent,
and inspect any monitoring equipment. The information that is collected is
available to the public. If a permittee does not want inspection information
to be available to the public, he or she must request the EPA Administrator
to consider the information confidential . The permittee must show that
the information, if made available, would divulge trade secrets. The
information then may be classified confidential, but still may be disclosed
to authorized representatives of EPA concerned with enforcing the Act.
Therefore, a business is entitled to a claim of confidentiality for all
information that an inspector requests or has access to; however, a
business may not refuse to release information requested by the inspector
under the authority of Section 308 of the Act on the grounds that the
information is considered confidential or a trade secret. The claim of
confidentiality relates only to the public availability of such data and
cannot be used to deny access to a facility to EPA inspectors performing
duties under Section 308 of the Act.
Handling Confidential Business Information
Routine security measures will help ensure that reasonable precautions
are taken to prevent unauthorized persons from viewing confidential
information. When practical circumstances prohibit the inspector from
following the procedures exactly, he or she should take steps to protect
NPDES Inspection Manual2-26January 1988
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Chapter Two Inspection Procedures
the information. All confidential information received must be marked as
such and placed in a locked filing cabinet or a safe immediately after
the inspection is completed. A chain-of-custody record must be maintained
for all confidential information.
Whi 1e Traveling.. The inspector may be on the road for several days while
conducting inspections. The inspector is responsible for ensuring that the
information collected is handled securely.
t Documents and field notes are considered secure if they are in the
physical possession of the inspector and are not visible to others
while in use.
• Inspection documents contain sensitive information and should be
kept in a locked briefcase. If it is impractical to carry the
briefcase, the briefcase may be stored in a locked area, such as
a motel room or trunk of a motor vehicle.
• Physical samples should be placed in locked containers and stored
in a locked portion of a motor vehicle. The chain-of-custody
procedures provide further protection for ensuring the integrity of
the sample.
In the Office. Only personnel authorized by the Regional Administrator,
Division Director, or Branch Chief will be allowed access to the file.
An access log should be maintained for all transactions. Copies should not
be made of information marked "trade secret" and/or "confidential" unless
written authorization has been obtained from the Regional Administrator,
Division Director, or Branch Chief. Requests for access to confidential
information by any member of the public, or by an employee of a Federal,
State, or local agency, shall be handled according to the procedures
contained in the Freedom of Information Act regulations (40 CFR Part 2).
All such requests shall be referred to the responsible Regional organi-
zational unit.
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Chapter Two
E CLOSING CONFERENCE
To achieve the most effective results from compliance inspections, the
inspector must communicate results promptly to the facility management
and/or operating personnel. However, the inspector's discussion should
be limited to specific findings of the visit. If appropriate, findings
should be compared with the permittee's NPDES permit requirements, consent
decrees, administrative orders, and other enforcement actions.
Precautions and Guidelines
Although a discussion of the inspection results is important, certain
precautions are essential:
• The inspector should not discuss compliance status or any legal
effects or enforcement consequences with the permittee's
representative or with facility operating personnel.
• The inspector should refrain from recommending a particular
consultant or consulting firm, even if asked to do so. Inspectors
should tell the permittee's representative to contact a
professional society or approved listing for advice concerning
this matter.
These guidelines are subject to rules promulgated by the Regional
Administrator or State Director regarding permittee contacts in the
Region/State.
Deficiency Notice
The inspector may issue a Deficiency Notice that specifies existing or
potential problems in a permittee's self-monitoring program. Issuing a
Deficiency Notice on-site or after the site visit provides a swift and
simple method for improving the quality of data from NPDES self-monitoring
NPDES Inspection Manual 2-29 January 1988
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Chapter Two Inspection Procedures
activities. An example Deficiency Notice is provided in Figure 2-2.
Notices allow the inspector formally to assign responsibility to the
permittee, and to track each stage of the compliance/enforcement process.
The Deficiency Notice also helps the permittee comply with the self-
monitoring requirements of the permit.
This tool should be used in conjunction with any type of NPDES compliance
inspection during which the inspector identifies problems with the permit-
tee's self-monitoring activities. It is to be used by the inspector only
to alert permittees to deficiencies in their self-monitoring activities.
The enforcement office of the regulatory authority, not the inspector,
handles effluent violations.
Inspectors can issue the Deficiency Notice to a permittee immediately
following a compliance inspection, or after the site visit is completed,
if they discover any permit deficiencies in the following seven categories
that the Notice addresses:
Monitoring location
Flow measurement
Sample collection/holding time
Sample preservation
Test procedures, Section 304(h), 40 CFR Part 136
Recordkeepi ng
Other self-monitoring deficiencies.
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Chapter Two
Inspection Procedures
DEFICIENCY NOTICE
NATIONAL POLLUTANT DISCHARGE
ELIMINATION SYSTEM (NPDES)
(Read instructions on oacfr of list part before completing)
PERMITTEE IFlctltlrl NAME AND ADDRESS
PERMITTEE REPRESENTATIVE (Receiving- thiw Notice)/ Tl TL E
NPOEJ PERMIT NO.
During the compliance inspection carried out on (date}
. the deficiencies noted below were found.
Additional areas of deficiency may be brought to your attention following a complete review of the Inspection Report and other in-
formation on file with the REGULATORY AUTHORITY administering your NPDES PERMIT.
MONITORING LOCATION (D»3cnbm>
FLOW MEASUREMENT fD
ADDITIONAL COMMENTS
REQUESTED ACTION—Your attention to tht correction of the deficiencies noted above is requested. Receipt of a description of the corrective actions
taken will be considered in the determination of the need for further Administrative or Ltisl Action. Your response is to be (InttMctor line out inappro-
prittt rwpenta) frwthod): (1 jinctudedwilh your nixt NPDES DUcharit Monitoring Report {DMR) or (2) submitted a* directed by the Inspector. Ques-
tions regarding possible follow-up action can be answered by the REGULATORY AUTHORITY to which your DMRs are submitted and which adminis-
ters your NPDES Permit.
INSPECTOR'S PRINTED NAME
INSPECTOR'S ADDRESS/PHONE NO.
REGULATORY AUTHORITY/ADDRESS
EPA Form 3BMM <2-W)
Figure 2-2
EPA Deficiency Notice Form
NPDES Inspection Manual
2-31
January 1988
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Chapter Two
F INSPECTION REPORT
The adequacy of compliance follow-up to correct problems or deficiencies
noted during inspection greatly depends on the report prepared by the
inspector. The sections of this chapter detail procedures for collecting
and substantiating the information used to prepare this report. Once
collected, however, the material must be organized and arranged so that
compliance personnel can make maximum use of it. The information presented
in this section provides general guidelines for organizing evidence and
preparing an inspection report.
Objective of the NPDETS Inspection Report
The objective of a NPDES inspection report is to organize and coordinate
all inspection information and evidence into a comprehensive, usable
document. To meet this objective, information in an inspection report
must be presented in a clear, wel1-organized manner. The information
should be objective and factual; the report should not speculate on the
ultimate result of the inspection findings. Of particular importance are
the following:
• Accurate information must be included in the report. It should
be factual and based on sound inspection practices. Observations
should be the verifiable result of firsthand knowledge. Compliance
personnel must be able to depend on the accuracy of all information,
• Information in an inspection report should be relevant to the
subject of the report. Irrelevant facts and data will clutter a
report and may reduce its clarity and usefulness. Personal
comments and opinions should be avoided.
• Suspected violation(s) should be substantiated by as much factual,
relevant information as is feasible to gather. All information
pertinent to the subject should be organized into a complete
package. Documentary support (e.g., photographs, statements,
sample documentation, etc.) accompanying the report should be
referenced clearly so that anyone reading the report will get a
complete, clear overview of the situation. The more comprehensive
the evidence is, the better and easier the prosecution's task
will be.
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Chapter Two Inspection Procedures
Elements of a Report
Although specific information requirements for an inspection report will
vary, most reports will contain the same basic elements:
• NPDES Compliance Inspection Report Form
• Supplementary narrative information
• Copies of completed checklists
• Documentary support.
NPDES Compliance Inspection Report Form
The inspector is responsible for reporting all compliance inspection
activities by completing the current Compliance Inspection Report Form as
soon as possible after the inspection. A copy of the form is included as
Figure 2-3. The Federal or State compliance office should forward the
inspection report form to the regulatory authority no later than 30 days
after completion of the inspection. Copies should be sent to the permittee
in a timely manner except when formal enforcement procedures are under
way. In this instance, the case attorney will direct any disclosure of
data.
Supplementary Narrative Information
Supplementary narrative information could be a memorandum in the case of
routine inspections or a narrative report when major violations are
detected. When a narrative report is necessary to describe fully a
compliance inspection, the contents of the report should focus on
supporting or explaining the information provided in the Compliance
Inspection Report Form.
The narrative report should be a concise, factual summary of observations
and activities, organized logically and legibly, and supported by specific
references to accompanying documentary support.
A work plan will simplify preparation and will help ensure that information
is organized in a usable form. Basic steps in writing the narrative report
include:
Reviewing the Information. The first step in preparing the narrative is
to collect all information gathered during the inspection. The inspector's
field notebook should be reviewed in detail. All evidence should be
reviewed for relevance and completeness. A telephone call or, in unusual
circumstances, a follow-up visit may be needed to obtain additional or
supplementary information.
Organizing the Material. The information may be organized according to
need, but it should be presented logically and comprehensively. The
narrative should be organized so that it is understood easily.
NPDES Inspection Manual 2-34January 1985
-------
Chapter Two Inspection Procedures
Referencing Accompanying Material. All documentary support accompanying
a narrative report should be referenced clearly so that the reader will
be able to locate the items easily. The "Documentation" section in this
chapter provides details on document identification. All documentary
support should be checked for clarity before writing the report.
Writing the Narrative Report. Once the material collected by the inspector
has been reviewed, organized, and referenced, the narrative can be written.
The purpose of the narrative is to record factually the procedures used
in, and findings resulting from, the evidence-gathering process. The
inspector should refer to routine procedures and practices used during
the inspection, but should detail facts relating to potential violations
and discrepancies. The field notebook is a guide for preparing the
narrative report.
If the inspector has followed the steps presented in this manual, the
report will develop logically from the organizational framework of the
inspection. In preparing the narrative, simplicity should be paramount.
Write simply; avoid stilted language
Use the active, not passive, approach: (e.g., "He said that . . ."
rather than "It was said that . . .")
Keep paragraphs brief and to the point
Avoid repetition
Proofread the narrative carefully.
Copies of Completed Checklists
Comprehensive checklists are included in the technical chapters of this
manual. When appropriate, these checklists may be used by the inspector
to collect information during the inspection or they may be modified by
the Region or State to address additional specific concerns. Copies of
all completed checklists should be included in the inspection report.
Documentary Support
All documentation produced or collected by the inspector to provide
evidence of suspected violations should be included in the inspection
report. The "Documentation" section in this chapter provides details on
obtaining and organizing this material.
The Permit Compliance System (PCS)
The inspection office should ensure that all data listed in Section A of
the NPDES Compliance Inspection Report are entered into the PCS, which is
used for National tracking of NPDES permit information. An inspection is
not credited to the inspection program office until coded into the PCS.
Therefore, timely completion of reports is essential to follow-up
effectively a compliance inspection. Every effort should be made to
ensure that data are entered no later than 30 days after the inspection
is completed.
NPDES Inspection Manual2-35January 1988
-------
Chapter Two
Inspection Procedures
United 5iaie> tnvifonm«n
tf\ M a-.^ -» Washington, 0
^>CrA NPDES Compliance
'«75SS«—«"«»
Inspection Report
Form Approved
OMB No. 2040-0003
Approval Expires 7-31 -85
Section A: National Data System Coding
Transaction Code NPDES yr/mo/day Inspection Type
1| | 2J 5| 3J | | 11 d 17 id I
Remarks
I
Inspector Fac Type
ig|_J 2C(_J-
! Ml
ii — ' — L— ' — ' — ' — ' — ' — ^ --1- * 56
Reserved Facility Evaluation Riling 81 QA Reserved
*1 1 1 |69 7d 1 71| I 72| I 73l I I 74 7-J 80
Section 8: Fecility Data
Nam* and Location of Facility Inspected
Entry Time r~| .
LJ A
Exit Time/Data
Namels) of On-Site Representative)*) Title(s)
Nam*. Address of Responsible Official Title
Phone
No.
M CD PM p«'m" Effective Date
Permit Expiration Date
Phone No(a)
Contacted
CD Yes CD No
Section C: Areea Evaluated During Inspection
(S - Satisfactory, M = Marginal. U = Unsatisfactory, N = Not Evaluated)
Permit Flow Measurement
Records/ Reports Laboratory
Pretreatment
Compliance Schedule*
Facility Sit* Review Effluent/Receiving Waters Self-Monitoring Program
Operations & Maintenance
Sludge Disposal
Other:
Section O: Summary of Findings/Comments (Artich additional shna ifntcfiifryl
Name(s) and Sighaturets) of Inspectorial Agency/Office/Telephone
Signature of Reviewer Agency/Office
Regulatory Offic* Use Only
Action Taken
Date
Date
Date
Compliance Status
L_ Noncompliance
l_ Compliance
Figure 2-3
NPDES Compliance Inspection Report Form
NPDES Inspection Manual
January 1988
-------
Chapter Two Inspection Procedures
INSTRUCTIONS
Section A: National Data System Coding (i.e.. PCS)
Column 1: Transaction Code: Use N, C, or D for New, Change, or Delete. All inspections will be new
unless there is an error in the data entered.
Columns 3-11: NPDES Permit No. Enter the facility's NPDES permit number. (Use the Remarks
columns to record the State permit number, if necessary.)
Columns 12-17: Inspection Date. Insert the date entry was made into the facility. Use the
year/month/day format (e.g., 82/06/30 = June 30, 1982).
Column 18: Inspection Type. Use one of the codes listed below to describe the type of inspection:
A — Performance Audit E — Corps of Engrs Inspection S — Compliance Sampling
8 — Biomonitoring L — Enforcement Case Support X — Toxic Sampling
C — Compliance Evaluation P — Pretreatment
D — Diagnostic R — Reconnaissance Inspection
Column 19: Inspector Code. Use one of the codes listed below to describe the lead agency in the
inspection.
C — Contractor or Other Inspectors (Specify in N — NEIC Inspectors
Remarks columns) R — EPA Regional Inspector
E — Corps of Engineers S — State Inspector
J —Joint EPA/State Inspectors—EPA lead T —Joint State/EPA Inspectors—State lead
Column 20: Facility Type. Use one of the codes below to describe the facility.
1 — Municipal. Publicly Owned Treatment Works (POTWs) with 1972 Standard Industrial Code
(SIC) 4952.
2 — Industrial. Other than municipal, agricultural, and Federal facilities.
3 — Agricultural. Facilities classified with 1972 SIC 0111 to 0971.
4 — Federal. Facilities identified as Federal by the EPA Regional Office.
Columns 21 -66: Remarks. These columns are reserved for remarks at the discretion of the Region.
Column 70: Facility Evaluation Rating. Use information gathered during the inspection (regardless
of inspection type) to evaluate the quality of the facility self-monitoring program. Grade the program
using a scale of 1 to 5 with a score of 5 being used for very reliable self-monitoring programs, 3 being
satisfactory, and 1 being used for very unreliable programs.
Column 71: Biomonitoring Information. Enter D for static testing. Enter F for flow through testing.
Enter N for no biomonitormg.
Column 72: Quality Assurance Data Inspection. Enter Q if the inspection was conducted as
followup on quality assurance sample results. Enter N otherwise.
Columns 73-80: These columns are reserved for regionally defined information.
Section B: Facility Data
This section is self-explanatory.
Section C: Areas Evaluated During Inspection
Indicate findings (S, M, U, or N) in the appropriate box. Use Section D and additional sheets as
necessary. Support the findings, as necessary, in a brief narrative report. Use the headings given on
the report form (e.g.. Permit, Records/Reports) when discussing the areas evaluated during the
inspection. The heading marked "Other may include activities such as SPCC, BMP's, and multime-
dia concerns.
Section D: Summary of Findings/Comments
Briefly summarize the inspection findings. This summary should abstract the pertinent inspection
findings, not replace the narrative report. Reference a list of attachments, such as completed
checklists taken from the NPDES Compliance Inspection Manuals and pretreatment guidance
documents, including effluent data when sampling has been done. Use extra sheets as necessary.
Figure 2-3
NPDES Compliance Inspection Report Form (Continued)
NPDES Inspection Manual2-38January 1988
-------
Chapter Three
RECORDKEEPING AND REPORTING
Contents Page
A Inspection Authority and Objectives
Authority and Objectives 3-1
B Evaluation Procedures
Verification, Recordkeeping, and Reporting
Evaluation Procedures 3-3
Compliance Schedule Status Review 3-5
Construction Progress 3-5
Construction Contracts and Equipment Orders 3-6
Authorization and Financing 3-6
Attainment of Operational Status 3-6
POTW Pretreatment Requirements Review 3-7
Indepth Investigations 3-8
Indepth Investigation Procedures 3-8
Verification, Recordkeeping, and Reporting
Evaluation Checklist 3-9
NPDES Inspection Manual 3-1 January 1988
-------
Chapter Three
A INSPECTION AUTHORITY AND
OBJECTIVES
Authority and Objectives
Statutory Recordkeeping Authority: Clean Water Act §308 and §402
Regulatory Requirements: 40 CFR Parts 122.41 and 122.48
Inspection Authority: Clean Water Act §308
The National Pollutant Discharge Elimination System (NPDES) permit system
requires permittees to maintain records and report periodically on the
amount and nature of effluent waste components. The permit stipulates
recordkeeping and reporting conditions. Evaluations are conducted at all
permittee facilities to determine compliance with permit requirements.
The procedures listed below should be used for these routine inspections.
If suspected violations are disclosed during the routine evaluation, a
more intensive investigation should be conducted.
A review of facility records should determine that recordkeeping
requirements are being met. In particular:
• Is all required information available?
• Is the information current?
• Is the information being maintained for the required time period?
• Do the records reviewed indicate areas needing further
investigations?
• Are the records organized?
NPDES Inspection Manual371January 1988
-------
Chapter Three
B EVALUATION PROCEDURES
Verification, Recordkeeping, and Reporting Evaluation Procedures
During the facility site inspection, the inspector should verify the
following requirements of the permit:
• That the number and location of discharges are as described in
the permit
• That all discharges are in accordance with the general provisions
of the permit, such as: no noxious odors, no discharge, no
visible entrained solids in discharge, and no fish or vegetation
kilIs near the outfalIs.
The inspector should review the permit to determine recordkeeping and
reporting requirements. Throughout the inspection, the facility's
operations should be compared with the permit to verify that required
permit activities are correct, current, and complete. Some of the
information needed to verify the permit can be obtained during the
opening conference and compared with the facility permit. This
information includes:
• Correct name and address of facility
t Correct name and location of receiving waters
• Number and location of discharge points
• Principal products and production rates (where appropriate).
The inspector should check for records that will verify that notification
has been made to EPA or to the State when: (1) discharges differ from
those stated in the permit, (2) a permit violation has occurred, and (3)
bypassing has occurred. The inspector should also check to ensure that
the appropriate records are maintained for a minimum of 3 years. These
records may include:
• Sampling and Analysis Data
- Dates, times, and locations of sampling
- Analytical methods and techniques
- Results of analyses
- Dates and times of analyses
- Name(s) of analysis and sampling personnel.
NPDElS Inspection Manual 3^3 January 1988
-------
Chapter Three Recordkeeping and Reporting
• Monitoring Records
- Discharge Monitoring Reports (DMRs) including information on flow,
pH, Dissolved Oxygen (DO), etc., as required by permit
- Original charts from continuous monitoring instrumentation.
• Laboratory Records
- Calibration and maintenance of equipment
- Calculations (i.e., on bench sheets or books)
- Quality Assurance/Quality Control (QA/QC) analysis data.
• Facility Operating Records
- Daily operating log
- Summary of all laboratory tests run and other required
measurements; should reference test method used (general reference
to Standard Methods is not adequate)
- Chemicals used (pounds of chlorine per day, etc.)
- Weather conditions (temperature, precipitation, etc.)
- Equipment maintenance completed and scheduled.
• Treatment Plant Records (required as part of the Federal
Construction Grants program)
- Plant Operations and Maintenance (O&M) Manual
- Percent removal records
- "As built" engineering drawings
- Copy of construction specifications
- Equipment supplier manual
- Data cards on all equipment.
• Management Records
- Average monthly operating records
- Annual reports
- Emergency conditions (power failures, bypass and chlorine
failure reports, etc.).
• Pretreatment Records
- Publicly Owned Treatment Works (POTW) and industrial monitoring
and reporting requirements
- Industrial user discharge data
- Compliance status records
- POTW enforcement initiatives.
• Spill Prevention Control and Countermeasure (SPCC) Plan
When required, a properly completed SPCC Plan should be available.
The inspector also may complete the SPCC inspection form and
forward the completed form to the appropriate program office for
follow-up action.
NPDES Inspection ManualttJanuary 1986
-------
Chapter Three Recordkeeplng and Reporting
• Best Management Practices
Two types of Best Management Practices (BMP) are included in
NPDES permits:
- BMP plans to minimize or prevent release of significant amounts
of any toxic or hazardous pollutants to public waters. The
plans may discuss general operations and maintenance of the
plant, good housekeeping procedures on the facility grounds, and
other plans and procedures specific to best management of the
facility.
- Site-specific BMP to address particular toxic or hazardous
chemicals or other conditions particular to the facility.
Site-specific BMP may include procedures, monitoring require-
ments, construction of barriers such as dikes and berms, or
other appropriate measures for solving specific problems.
The inspector should document all inspection activities (see Chapter Two,
Section D). Inadequacies, discrepancies, or other problems disclosed
during this review may warrant more intensive investigation.
Compliance Schedule Status Review
If the permit contains a compliance schedule, a status review should be
conducted to determine:
• Whether the permittee is conforming to the compliance schedule
and, if not, whether final requirements will be achieved on time
• The accuracy of reports relating to compliance schedules
• The length of delay associated with a particular construction
violation
• Whether any schedule violations are beyond the control of the
discharger
t Whether requests for permit modifications are valid.
If the permit contains a compliance schedule for actions such as beginning
new construction, contract and equipment orders, authorization and financing
arrangements, and/or attainment of operational status; the schedule
should be addressed in detail only if the need becomes apparent during
records review and preparation of the inspection plan. The specific
compliance schedule actions are described below.
Construction Progress
The inspector must know whether contracts for labor and material have been
fulfilled and whether the permittee or the permittee's engineering consultant
is monitoring progress. These aspects are extremely important, particularly
in plants where numerous contracts are likely for labor and equipment.
NPDES Inspection Manual 3-5 January 1988
-------
Chapter Three Recordkeeping and Reporting
If the permittee or the engineering consultant reports that construction
or the acquisition of equipment is behind schedule, the inspector should:
• Ask to see the permittee's or the resident engineer's progress
report and determine whether the report indicates that the final
compliance schedule required by the permit can be met.
• If the report indicates that the final date will not be met, advise
the permittee that the compliance schedule of the NPDES permit
requires the permittee to notify the permit-issuing authority
promptly of any possible delay in achieving compliance and of
measures taken to minimize the delay.
• Inquire whether the facility superintendent or chief operator and
operating personnel are receiving adequate training concerning the
operational aspects of the new treatment unit while construction
is under way- They must be prepared to perform the essential
operating functions when the facility is placed in service.
Construction Contracts and Equipment Orders
The inspector should review the appropriate documents to determine whether
the permittee has obtained the necessary approval to begin construction.
The inspector should note the start and completion dates (or scheduled
delivery dates in service or equipment contracts).
Authorization and Financing
If construction is incomplete, the inspector should determine whether the
permittee has the authority and financial arrangements (mortgage commitments,
corporate resolution, etc.) to complete the required structures.
Attainment of Operational Status
If construction has been completed but the facility is not yet operational,
the inspector should determine whether appropriate procedures are being
used to ensure attainment of working status at the earliest possible
time.
The inspector should verify that:
• Adequate self-monitoring procedures have been initiated. It is
especially important that the result of operational and effluent
quality monitoring be reviewed to determine whether progress is
being made toward optimum efficiency in each treatment unit and
in the enti re plant.
• Adequate recordkeeping procedures have been established or
initiated.
NPDES Inspection ManualttJanuary 1988
-------
Chapter Three Recordkeeplng and Reporting
t Adequate work schedules and assignments have been established.
(For municipal facilities, the O&M Manual should provide
essential guidance.)
POTW Pretreatment Requirements Review
The inspector must collect specific information to evaluate compliance
with pretreatment requirements. The procedures developed to collect
this information are summarized below and discussed in greater detail in
Chapter Nine, "Pretreatment."
The inspector must determine the status of pretreatment program development
and/or implementation by the POTW.
• When was the program approved by EPA/State or is the approval
in progress?
• Is the frequency of monitoring significant industrial discharges
the same as stated in the approved pretreatment program?
• Have permits been issued to significant industrial users?
• Have inspections of significant industrial users been initiated?
As part of the inspection, the inspector must collect information about
the compliance status of contributing significant industrial facilities
with categorical pretreatment standards or locally developed discharge
limitations. The inspector should review POTW records to determine:
• Number of contributing industries
• Whether these industries have been properly classified for the
applicable standards
• Whether industries have submitted required reports to the POTW,
including baseline monitoring reports, 90-day compliance reports,
POTW required industrial self-monitoring reports, etc.
• Number of contributing industries in compliance with applicable
standards
t Whether all noncompliant industries have been put on an enforce-
able compliance schedule
• Whether contributing industries with compliance schedules are
meeting applicable schedule deadlines.
The inspector should note in the inspection report if the locally developed
discharge limits applied are more stringent than EPA categorical pretreat-
ment standards. The POTW is required to determine if locally developed
discharge limitations are required to protect the collection system,
treatment plant, sludge, and/or receiving waters from interference or
pass through of industrial pollutants.
NPDE"S Inspection Manual 377 January 1988
-------
Chapter Three Recordkeeping and Reporting
Indepth Investigations
An indepth inspection of a permittee's records and reports will be
conducted when necessary to substantiate a suspected violation, to verify
self-monitoring data that may be used as corroborative evidence in an
enforcement action, or to confirm apparent sampling, analysis, or reporting
discrepancies discovered during the limited inspection. Discrepancies
warrant an indepth review if, for example:
• The discharge does not meet required standards and no definite
operational problems have been established
• Self-reported data are suspected to be grossly inaccurate and the
problem appears to be with recordkeeping procedures and/or the
filing of reports
0 The cursory review indicates omissions or laxity in the preparation
of records
• There is evidence of falsification of records.
If more guidance or assistance is needed in performing an indepth
investigation, the inspector should confer with his or her supervisor.
Indepth Investigation Procedures
The following procedures should guide the inspector in conducting an
indepth investigation:
• Determine Investigation Objective. What is the specific purpose of the
investigation?
• Determine Information Needed. What specific data will substantiate a
violation or respond to the investigation objective?
t Determine Data Source. What records will contain these required data?
* Review Inspection Authority. Authority to inspect under Section 308 is
limited to those records required by the permit. Specific authority may
be necessary to inspect other documents.
• Inspect Direct and Indirect Data Sources. Examine records likely to
provide the required data directly. In the absence of direct data,
indirect sources of information can be used to develop a network of
information relevant to the data being sought.
• Take Statements from Qualified Facility Personnel. See Chapter Two,
Section D, for procedures.
• Prepare Documentation. Copy and identify all records relevant to the
information being sought; see Chapter Two, Section D, for specific
procedures.
• Follow Confidentiality Procedures. Any record inspected may be claimed
by the facility as confidential. Such records must be treated in
accordance with EPA procedures; see Chapter Two, Section D, the
discussion on Confidential Business Information.
NPDES Inspection Manual 3^13 January 1988
-------
Chapter Three
Recordkeeplng and Reporting
VERIFICATION, RECORDKEEPING, AND REPORTING EVALUATION CHECKLIST
A. PERMIT VERIFICATION
Maili ng Address:
Brief Facility Description:
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
1. Inspection observations verify information contained
in permit.
2. Current copy of permit on-site.
3. Correct name and mailing address of permittee.
4. Facility as described in permit.
5. Notification given to EPA/State of new, different, or
increased discharges.
6. Accurate records of influent volume maintained, when
appropriate.
7. Number and location of discharge points as described
in permit.
8. Name and location of receiving waters correct.
9. All discharges permitted.
10. Federal Construction Grant funds used to build plant,
4.
B. RECORDKEEPING AND REPORTING EVALUATION
1. Records and reports maintained as required by permit.
2. All required information available, complete, and
current.
3. Information maintained for 3 years.
Analytical
DMRs.
results consistent with data reported on
5. Sampling and analyses data adequate and include:
a. Dates, times, and location of sampling
b. Name of individual performing sampling
c. Analytical methods and techniques
d. Results of analyses and calibration
e. Dates of analyses
f. Name of person performing analyses
g. Instantaneous flow at grab sample stations.
6. Monitoring records adequate and include:
a. Flow, pH, DO, etc., as required by permit
b. Monitoring charts kept for 3 years
c. Flowmeter calibration records kept.
7. Laboratory equipment calibration and maintenance
records adequate.
NPDES Inspection Manual
3-9
January 1988
-------
Chapter Three
Recordkeeping and Reporting
VERIFICATION, RECORDKEEPING, AND REPORTING EVALUATION CHECKLIST
(Continued
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
8. Plant records* adequate and include:
a. O&M Manual
b. "As-built" engineering drawings
c. Schedules and dates of equipment maintenance
repairs
d. Equipment supplies manual
e. Equipment data cards.
* Required only for facilities built with Federal
construction grant funds.
9. Pretreatment records adequate and include inventory
of industrial waste contributors, including:
a. Monitoring data
b. Inspection reports
c. Compliance status records
d. Enforcement actions.
C. COMPLIANCE SCHEDULE STATUS REVIEW
1. Permittee is meeting compliance schedule.
2. Permittee has obtained necessary approvals to begin
construction.
3. Financing arrangements complete.
4. Contracts for engineering services executed.
5. Design plans and specifications completed.
6. Construction begun.
7. Construction on schedule.
8. Equipment acquisition on schedule.
9. Construction completed.
10. Startup begun.
11. Permittee requested an extension of time.
12. Permittee met compliance schedule.
D. POTW PRETREATMENT REQUIREMENTS REVIEW
THE FACILITY IS SUBJECT TO PRETREATMENT REQUIREMENTS
1. Status of POTW pretreatment program
a. The POTW pretreatment program has been approved by
EPA. (If not, is approval in progress? )
D. [he PUIW is in compliance with the pretreatment
program compliance schedule. (If not, note why,
what is due, and intent of the POTW to remedy)
NPDES Inspection Manua'
3-10
January 1988
-------
Chapter Three
Recordkeeplng and Reporting
VERIFICATION, RECORDKEEPING, AND EVALUATION CHECKLIST
(Continued)
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
2. Status of Compliance with Categorical Pretreatment
Standards.
a. How many industrial users of the POTW are subject
to Federal or State pretreatment standards?
b. Are these industries aware of their responsibility
to comply with applicable standards?
c. Have baseline monitoring reports (403.12) been
submitted for these industries?
i. Have categorical industries in noncompliance
(on BMR reports) submitted compliance
schedules?
ii. How many categorical industries on compliance
schedules are meeting the schedule
deadlines?
d. If the compliance deadline has passed, have all
industries submitted 90-day compliance reports?
e. Are all categorical industries submitting the
required semiannual report?
f. Are all new industrial discharges in compliance
with new source pretreatment standards?
g. Has the POTW submitted an annual pretreatment
report?
h. Has the POTW taken enforcement action against
noncomplying industrial users?
i. Is the POTW conducting inspections of industrial
contributors?
3. Are the industrial users subject to Prohibited Limits
(403.5) and Local Limits more stringent than EPA in
compliance?
(If not, explain why, including need for revision
of limits.)
NPOES Inspection Manual
TTT
January 1988
-------
Chapter Four
FACILITY SITE REVIEW
Contents Page
A Objectives 4-1
B Physical Inspection of the Facility
General Conditions in Overall Plant 4-4
General Indicators 4-4
Flow Indicators 4-4
Unusual Wastes Indicators 4-5
Preliminary Treatment 4-5
Screening 4-5
Shredding/Grinding 4-5
Grit Removal 4-5
Primary Clarifier 4-5
General Indicators 4-5
Secondary Biological Treatment Units 4-6
Trickling Filter 4-6
Rotating Biological Contactors 4-6
Activated Sludge Tanks 4-6
Stabilization Ponds 4-6
Secondary Clarifier 4-7
General Indicators 4-7
Advanced Physical Treatment Units 4-7
Filtration 4-7
Microscreening 4-7
Activated Carbon Adsorption 4-7
Nitrification 4-7
Deni tri ficati on 4-8
Ammonia Stripping 4-8
Chlorination and Dechlorination Units 4-8
Chlorination 4-8
Dechlorination 4-8
Sludge Handling 4-9
General Indicators 4-9
Sludge Anaerobic Digestion 4-9
Sludge Aerobic Digestion 4-9
NPDES Inspection Manual 4-i January 1988
-------
Chapter Four Contents
Sludge Drying/Filtering 4-9
Sludge Disposal 4-10
Polishing Ponds or Tanks 4-10
Plant Effluent 4-11
Flow Measurement 4-11
Chemical Treatment Units 4-11
General Housekeeping 4-11
Production Changes 4-12
C Operation and Maintenance Evaluation
Operation Evaluation 4-13
Policies and Procedures 4-13
Staffi ng 4-13
Health and Safety 4-14
Management Controls 4-14
Maintenance Evaluation 4-14
D References and Facility Site Review Checklist
References 4-25
Facility Site Review Checklist 4-27
List of Tables
4-1 Operations and Maintenance Function Evaluation Questions .... 4-17
NPDES Inspection Manual4-iiJanuary 1988
-------
Chapter Four
A OBJECTIVES
In performing a facility site review, an inspector examines treatment units,
monitoring equipment, outfalls, and the receiving stream. In particular, the
inspector focuses on areas of the permittee's premises where pollutants are
pumped, conveyed, treated, stored, or disposed. The proper conduct of a
facility site review requires that the inspector understand fully the wastewater
treatment processes used at the facility and how each process fits into the
overall treatment scheme.
The objectives of a facility site review are to:
• Assess the conditions of the facility's current treatment
processes and operations
• Evaluate the permittee's operation and maintenance activities
• Check the completeness and accuracy of the permittee's
performance/compliance records
• Determine if the treatment units are being operated as efficiently
as possible.
During the overall review of the facility, the compliance inspector
becomes more knowledgeable about the facility being inspected, reviews
areas that may indicate problems with effluent limitations, and evaluates
overall performance of the treatment facility. Because the information
presented in this chapter is comprehensive, inspectors should use only the
information applicable to a particular situation. A Facility Site Review
Checklist for the inspectors' use is included at the end of this chapter.
NPDES Inspection Manual 4-1 January 1988
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Chapter Four
B PHYSICAL INSPECTION OF THE
FACILITY
During the physical "walk-through" of the facility, the inspector should
consider the operational factors listed below. Since these factors may
indicate problems, the physical inspection should be carefully documented.
Areas that should be covered are:
• Influent characteristics, including:
- Combined sewer loads
- Infiltration/inflow
- Industrial contributions
- Diurnal/seasonal loading variations
Process control
Unit operations
Equipment condition
Safety controls and equipment
Effluent characteristics, including:
- Appearance of outfall
- Receiving stream appearance
- Evidence of toxicity of the discharge
• Other conditions particular to the plant.
EPA's Field Manual for Performance Evaluation and Trouble Shooting at Municipal
WastewTter Facilities (USEPA 1978), published by the Municipal Operations
Branch of EPA, is a good reference for operational characteristics of
plants.
The physical inspection may lead the inspector to determine:
• Whether a major facility design problem requires an engineering
solution
• If problem areas can be solved through proper operation and maintenance
of the treatment facilities
• Whether periodic equipment malfunctions need to be addressed by
complete overhaul or replacement of equipment.
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Chapter Four
Faci1ity Site Review
If a facility design problem exists, one of the recommendations will be to
develop engineering solutions. In this case, the inspector must evaluate
the operation and maintenance procedures from the viewpoint of what can be
done to simplify the solution. When the inspection findings indicate that
specific practices of the facility contribute to or cause problems, the
inspector should detail the problems and make recommendations. When possible
the inspector should use the information to evaluate the operation and
maintenance procedures.
When conducting the walk-through, the inspector should be aware of and
look for physical conditions which indicate potential or existing problems.
The presence of these conditions will give the inspector an idea of the
types of problems present, the parts of the treatment process causing the
problems, and the potential solution to existing problems. Conditions to
look for in the plant generally and in specific processes are listed in the
following sections.
General Conditions in Overall Plant
General Indicators
• Excessive scum buildup, grease, foam, or floating sludge in
clarifiers
• Hydraulic overload caused by storms or discharges of cooling
water
• Noxious odors in wet wells and grit chambers and around aerobic
and anaerobic biological units, scum removal devices, and sludge
handling facilities
• Evidence of severe corrosion at the treatment plant and in the
collection system
• Discoloration of the ground or a strong chemical smell may indicate
past spills at the plant; further investigation of spills may be
warranted.
• Vital treatment units out of service for repairs. Determine when
the units went out of service, the type of failure, and when they
will be put back in service.
• Excessive noise from process or treatment.
• Any unusual equipment, intended to correct operation problems
(e.g., special pumps, floating aerators in diffused air systems,
chemical feeders, temporary construction or structures, or any
improvised system).
• Ruptures in chemical feed lines.
Flow Indicators
• Surcharging of influent lines, overflow weirs, and other structures.
• Flow through bypass channels.
• Overflows at alternative discharge points, channels, or other areas.
• Excessive septage dumping by septic tank pumpers.
NPDES Inspection Manual
January 1988
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Chapter Four Facility Site Review
t Open-ended pipes that appear to originate in a process or storage
area and periodically contain flows to the ground or to surface
water. Although these pipes have been disconnected from a closed
system or otherwise removed from service, they can still be con-
nected to a discharge source.
Unusual Wastes Indicators
• Collected screenings, slurries, sludges, waste piles, or by-products
of treatment. Their disposal, including runoff of any water, must
be such that none enters navigable waters or their tributaries.
• No recycling of filtrates and supernatants from sludge beds.
• Improper storage of chemicals and hazardous substances with
particular attention to the proper diking of chemicals and
hazardous substances.
• Spills or mishandling of chemicals.
Preliminary Treatment
Screening
t Excessive screen clogging.
Shredding/Grinding
• Excessive build up of debris against screen
• Grit chamber clogged or subject to odors.
Grit Removal
• Excessive organic content of grit.
Primary Clarmer
General Indicators
Excessive gas bubbles or grease on surface
Black and odorous wastewater
Poor suspended solids removal in primary clarifier
Excessive buildup of solids in center well of circular clarifier
Discharge weirs unlevel
Evidence of short circuiting
Scum rake ineffective
Scum overflow or lack of adequate scum disposal, scum pit full
Excessive floating sludge
NPDES Inspection Manual^January 1988
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Chapter Four Facility Site Review
• Excessive sludge on bottom, inadequate sludge removal
t Noisy sludge scraper drive
• Broken sludge scraper
Secondary Biological Treatment Units
Trickling Filter
Trickling filter ponding (indicating clogged media)
Leak at center column of trickling filter's distribution arms
Uneven distribution of flow on trickling filter surface
Clogging of trickling filter's distribution arm orifices
Restricted rotation of distribution arms
Filter flies
Ice buildup on trickling filter media or distribution arms.
Rotating Biological Contactors
• Development of white biomass on rotating biological contactor (RBC)
medi a
• Excessive breakage of rotating disks or shafts in RBC units
• Excessive breakage of paddles on brush aerators
• Shaft, bearing, drive gear, or motor failure on disk or brush
aerators.
Activated Sludge Tanks
Dead spots in aeration tanks; dark foam or bad odor in aeration tanks
Failure of surface aerators
Inoperative air compressors
Air rising in clumps
Excessive air leaks in compressed air piping
Dark mixed liquor in aeration tank
Dark foam or bad odor on aeration tanks
Stable dark tan foam on aeration tanks that sprays cannot break up
Thick billows of white, sudsy foam on aeration tank
Low Dissolved Oxygen (DO, < 1.0 mg/1) in aeration tank.
Stabilization Ponds
0 Erosion of stabilization pond bank or dike
• Excessive weeds in stabilization ponds
• Foaming and spray in aerated lagoon
• Dead fish or aquatic organisms.
NPDES Inspection Manual?I5January 1988
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Chapter Four Facility Site Review
Secondary Clarlfier
General Indicators
Excessive gas bubbles on surface
Fouling of overflow weirs
Overflow weirs unlevel
Evidence of short circuiting
Excessive buildup of solids in center well of circular clarifier
Deflocculation in clarifier
Pin floe in overflow
Scum rake ineffective
Sludge floating to surface
Billowing sludge
Sludge blanket too high
Sludge withdrawal ports on secondary clarifier clogged.
Advanced Physical Treatment Units
Filtration
Filter surface clogging
Short filter run
Gravel displacement of filter media
Formation of mud balls in filter media
Air binding of filter media
Loss of filter media during backwashing
Recycled filter backwash water in excess of five percent,
Microscreening
• Erratic rotation of microscreen drums.
Activated Carbon Adsorption
• Excessive biological growth resulting in strong odor
• pH above 9.0
• Plugged carbon pores
• Presence of carbon fines (dust) in effluent.
Nitrification
• Hydraulic overload.
NPDES Inspection Manual 4-7 January 1988
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Chapter Four Facility Site Review
Denitrlflcatlon
t Temperature below 15°C
• pH below 6.0°C or above 8.0°C
t Excessive methanol.
Ammonia Stripping
Excessive hydraulic loading rate
Tower packing coated with calcium carbonate
pH below 10.8
Inadequate tower packing depth
Air temperature below 65°F.
Chlorination and Dechlorination Units
Chlorination
Sludge buildup in contact chamber
Gas bubbles noted
Inadequate retention time
Floating scum and/or solids
Evidence of short circuiting
Inadequate ventilation of chlorine feeding room and storage area
Hiyh temperatures in Chlorination rooms
Improper operation of automatic feed or feedback control
Excessive foaming downstream
Evidence of toxicity downstream (dead fish, other dead organisms)
Improper chlorine feed, storage, and reserve supply.
Dechlorination
Improper storage of sulfur dioxide cylinders
Inadequate ventilation of sulfur dioxide feeding room
Automatic sulfur dioxide feed or feedback control not operating
properly
Depressed DO after dechlorination
Proper storage and mixture of sodium metabisulfite containers
Reduced efficiency of activated carbon dechlorination units because
of organic and inorganic compound interference.
NPDES Inspection Manual4^8January 1988
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Chapter Four Facility Site Review
Sludge Handling
General Indicators
Inadequate sludge removal from clarifiers or thickeners
Poor dewatering characteristics of thermal treated sludge
Thickened sludge too thin
Fouling of overflow weirs on gravity thickeners
Air flotation skimmer blade binding on beaching plate
Substantial down time of heat treatment unit
Sludge disposal inadequate to keep treatment system in balance.
Sludge Anaerobic Digestion
Mechanical or gas mixers inoperative
Sludge heater inoperative
Floating cover of anaerobic digester tilting
Inadequate gas production
Gas burner not burning or inoperative
Supernatant exuding a sour odor from either primary or secondary
anaerobic digester
• pH problems from industrial wastewaters with high sugar content.
Sludge Aerobic Digestion
Excessive foaming in tank
Objectionable odor in aerobically digested sludge
Insufficient DO in digester
Digester overloaded
Clogging of diffusers in digester
Mechanical aerator failure in digester
Inadequate supernatant removal from sludge lagoons
Sludge lagoons full, overflowing sludge back to plant or to natural
drainage.
Sludge Drying/Filtering
Poor sludge distribution on drying beds
Vegetation in drying beds
Dry sludge remaining in drying beds
Some drying beds unused
Dry sludge stacked around drying beds where runoff may enter
navigable waters
NPDES Inspection Manual 4-9 January 1988
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Chapter Four Facility Site Review
Excessive drying time of sludge on drying bed
Filtrate from sludge drying beds returned to front of plant
Excessive solids in fluid phase of sample after centrifugation
Inadequate dryness of centrifugal sludge cake
High level of solids in filtrate from filter presses or vacuum
filters
Thin filter cake caused by poor dewatering
Vacuum filter cloth binding
Low vacuum on filter
Improperly cleaned vacuum filter media
Sludge buildup on belts and/or rollers of filter press
Excessive moisture-in belt filter press sludge cake
Difficult cake discharge from filter presses
Filter cake sticks to solids-conveying equipment of filter press
Frequent media binding of filter press
Sludge blowing out of filter press
Insufficient run time of sludge dewatering equipment
Objectionable odor from sludge lagoon
Broken dikes between sludge drying lagoons
Unlined sludge lagoons.
Sludge Disposal
Sludge constituents not analyzed before disposal
Sludge not transported in appropriate and approved vehicle
Surface runoff of sludge at land application site
Liquid sludge (i.e., less than 10 percent solids) applied to land-
fill site
Inadequate coverage of sludge in subsurface plow injection system
Malodors generated at land application site
Slow drying of soil-sludge mixture in subsurface injection system
Sludge ponding at land application sites
Flies breeding and/or odors at landfill site
Inadequate burial of sludge at landfill site
Excessive erosion at sludge sites
Waste sludges disposed on-site in nonpermitted sites or in
landfills, surface impoundments, or land application units not
according to Federal, State, or local regulations
Inadequate runoff control at landfill or land application sites.
Polishing Ponds or Tanks
• Objectionable odor, excessive foam, floating solids, or oil sheens
in polishing ponds or tanks
• Solids or scum accumulations in tank or at side of pond
• Evidence of bypassed polishing ponds or tanks because of low
capacity.
'DES Inspection Manual 4-10 [January iggg
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Chapter Four
Facility Site Review
Plant Effluent
a Excessive suspended solids, turbidity, foam grease, scum, color,
and other macroscopic particulate matter present
• Potential toxicity (dead fish, dead plants at discharge).
Flow Measurement
Flow totalizer not calibrated
Buildup of solids in flume or weir
Broken or cracked flume or weir
Magnetic flowmeter not functioning properly
Stilling wells clogged or broken
Weir plate edge corroded or damaged, not sharp edged (_< 1/8"), or
not level
Incapable of measuring maximum flow
Sizing of system adequate to handle flow range.
Chemical Treatment Units
Heavy corrosion evident
No portion-measuring device at feed unit
pH measuring not evident at pH adjustment tank
Chemicals left in open atmosphere
Chemicals outdated
Chemical containers stored improperly or hazardously
Chemical tanks cars (trucks or train) stored, moved, or handled
inappropriately
Dry chemicals spilled on floor between storage area and feed units
Empty chemical containers improperly disposed of
Large containers handled improperly, container transfer equipment
not maintained
No appropriate sized berms or dikes at liquid chemical feed units
Inadequate supply of chemicals
Chemical dust covering feed unit area or storage and transfer
areas
Use of an inappropriate coagulant
Glass carboys (acid storage) stored or handled improperly.
General Housekeeping
• Facility control panel in disrepair or not in use
• Wastewater pipelines not clearly distinguished from product
pipelines.
January 1988
TTPDES Inspection Manual
4-11
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Chapter Four
Facility Site Review
Production changes
Industries frequently make production changes
technology and availability of new products.
of an industrial facility, the inspector also
because of advances in
Therefore, during the tour
should inquire:
t
•
Whether a permittee has made any changes to:
- Production processes
- Raw materials
- Amount of finished product
- Water use
- Waste treatment processes
- Other such changes
Whether the permittee has modified any production process that would
change the pollutant loading
Whether the regulatory agency was notified of such changes
What changes will need to be reflected in any National Pollutant
Discharge Elimination System (NPDES) permit modifications.
The inspector should verify any changes and include the results of the
findings and other pertinent information in the Compliance Inspection
Report. Changes in the loading to Publicly Owned Treatment Works (POTWs)
the addition of a significant industrial discharger or large population
growth also should be ascertained and reported.
by
NPDES Inspection Manual
4-12
January 1988
-------
Chapter Four
C OPERATION AND MAINTENANCE
EVALUATION
Operation Evaluation
Operating factors affecting plant performance range from qualitative
factors such as the skills and aptitudes of operators (e.g., process
knowledge and general aptitude), to physical deficiencies in laboratory
equipment or a lack of flexibility in process equipment. The evaluation of
operation functions must focus on wastewater treatment, sludge treatment/
disposal, and laboratory analysis. The evaluation should be based on the
following topics:
• Policies and procedures
• Organization
• Staffing
t Planning
• Management controls.
Table 4-1 presents the basic review questions that an inspector should ask in
evaluating operation functions. Although each of the preceding evaluation
topics must be covered in the review of operation functions, the following
four areas should particularly concern the inspector:
Policies and Procedures
Written operating procedures and standard reference texts enable the
operator to achieve efficient plant operation. The operations manual
prepared for the facility is the most important reference that an
inspector should review when evaluating plant policies and procedures.
Other reference materials relating to operations that should be available
to the operator include manufacturers' literature, publications by
professional organizations (e.g., the Water Pollution Control Federation),
and EPA publications.
Staffing
Even the best engineered facility cannot perform to its potential without
a sufficient number of capable and qualified staff. The inspector must
consider the abilities and limitations of the operating staff. Staff inter-
NPDES Inspection Manual4-13January 1988
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Chapter Four Facility Site Review
views may include the individual in charge of overall operation, the chief
operator, specific unit process operators, and laboratory staff.
Health and Safety
At all times, safe operating procedures should be followed. Employees must
be trained in emergency shut-down, fire control, and spill response procedures,
as well as in the use of safety equipment, safe sampling techniques, and the
safe handling of chemicals and wastes. Managers must be aware of the OSHA
Right-to-Know laws regarding potentially dangerous chemicals in the workplace.
This law specifically requires a written hazard communication program, labeling
of chemicals, and the availability of material safety data sheets to employees
upon request.
Management Controls
Monitoring practices are a good indicator of both the emphasis placed on
operations and the operator's understanding of process controls. Factors
affecting a facility's monitoring capabilities are:
• The sampling program
• Performance testing
• Analytical capabilities
t Recordkeeping practices.
An effective process control program is essential to a treatment facility's
optimal performance. However, process control cannot be easily quantified
by the inspector. In most cases, the inspector must rely on discussions
with the plant superintendent and/or operators to supplement available
records and the technical evaluation. The key considerations for effective
process controls are:
Process control data
Process knowledge of the operators
The basis for the control practices
Implementation of the control practices
Past performance
Operator emphasis on controls
Recordkeeping.
Maintenance Evaluation
Facility maintenance directly affects the ability of the facility to run
efficiently and to comply with its NPDES permit. The two types of facility
maintenance are:
• Preventive maintenance
- Reduces facility operating costs by eliminating breakdowns and
the need for corrective maintenance
NPDES Inspection ManualSTT3January 1988
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Chapter Four Facility Site Review
- Improves the facility's reliability by minimizing the time
equipment is out of service
- Increases the useful life of equipment, thus, avoiding costly
premature replacement
- Avoids possible compliance violations
t Corrective maintenance
- Returns malfunctioning equipment to operation
- Avoids or minimizes possible compliance violations.
Evaluation of the maintenance function must focus on the ability to maintain
process equipment, vehicles, and building and grounds. Although each of the
five evaluation topics (policies and procedures, organization, staffing,
planning, and management controls) must be covered for each facility inspected,
the principal areas of concern in the operations evaluation are the same in
the maintenance function:
t Staffing and training
• Planning and scheduling
• Management control—records systems and inventory control.
Only wel1-trained, competent plant staff can be expected to perform adequate
physical inspections, repairs, and preventive maintenance. Wastewater
facility maintenance is complex and requires a variety of skills. Because
many of these skills are not readily available, an ongoing training program
is essential.
Maintenance planning and scheduling is essential to effective corrective
and preventive maintenance. The maintenance supervisor must prepare work
schedules listing job priorities, work assignments, available personnel,
and timing.
A detailed records system is the basis of any maintenance program. Records
are used to establish maintenance histories on equipment, diagnose problems,
and anticipate—and thereby avoid—equipment failure, making records an
effective tool for preventive maintenance.
A central inventory of spare parts, equipment, and supplies must be
maintained and controlled. The basis for the inventory should be the
equipment manufacturer's recommendations, supplemented by specific,
historical experience with maintenance problems and requirements.
Inventoried supplies must be kept at levels sufficient to avoid process
interruptions.
A maintenance cost control system should be an integral part of every
wastewater facility. Budgets must be developed from past cost records
and usually are categorized according to preventive maintenance, corrective
maintenance, and projected and actual major repair requirements. Annual
costs must be compared to the budget periodically to control maintenance
expenditures. Evaluating costs this way serves to control expenditures and
as a baseline for future budgets.
The basic concerns that need to be addressed and evaluated during the
inspector's maintenance program review are presented at the end of this
section in Table 4-1.
NPDES Inspection Manual4-15January 1988
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Chapter Four Facility Site Review
Table 4-1
Operations and Maintenance Function Evaluation Questions
Policies and Procedures
• Is there a formal or informal set of policies for facility
operations?
• Do policies address:
- Remaining in compliance
- Maintaining process controls
- Quality control
- Preventive maintenance?
• Is there a set of standard procedures to implement these
policies?
• Are the procedures written or informal?
• Do the procedures consider the following areas:
- Safety - Collection system
- Emergency - Pumping stations
- Laboratory - Treatment process
- Process control - Sludge disposal
- Operating procedures - Equipment record system
- Monitoring - Maintenance planning and
- Labor relations scheduling
- Energy conservation - Work orders
- Inventory management?
• Are the procedures followed?
Organization
• Is there an Organizational Plan (or Chart) for operations?
• Does the Plan include:
- Delegation of responsibility and authority
- Job descriptions
- Interaction with other functions (such as maintenance)?
NPDES Inspection Manual 4-17 January 1988
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Chapter Four Facility Site Review
Table 4-1
Operations and Maintenance Function Evaluation Questions (Continued)
• Is the Plan formal or informal?
• Is the Plan available to and understood by the staff?
0 Is the Plan followed?
• Is the Plan consistent with policies and procedures?
• Is the Plan flexible? Can it handle emergency situations?
• Does the Plan clearly define lines of authority and responsi-
bility in such subfunctional areas as:
- Laboratory - Monitoring practices
- Process control - Mechanical
- Instrumentation - Electrical
- Sludge disposal - Buildings and grounds
- Collection system - Automotive
- Pumping stations - Supplies and spare parts?
Staffing
• Is there an adequate number of staff to achieve policies and
procedures?
• Are staff members adequately qualified for their duties and
responsibilities by demonstrating:
- Certification
- Quali fications
- Ability
- Job performance
- Understanding of treatment processes?
• Is staff effectively used?
• Has the potential for borrowing personnel been considered?
• Are training procedures followed for:
- Orientation of new staff
- Training new operators
- Training new supervisors
- Continuing training of existing staff
- Cross training?
NPDES Inspection Manual4-18January 1988
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Chapter Four Facility Site Review
Table 4-1
Operations and Maintenance Function Evaluation Questions (Continued)
§ Which of the following training procedures are used:
- Formal classroom
- Home study
- On-the-job training
- Participation in professional organization
• Does the training program provide specific instruction for the
following operations and maintenance activities:
- Safety - Handling emergencies
- Laboratory procedures - Mechanical
- Treatment processes - Electrical
- Instrumentation - Automotive
- Equipment troubleshooting - Building maintenance
- Handling personnel problems - Inventory control?
- Monitoring practices
• Does management encourage staff motivation?
• Does management support its first-line supervisors?
t Is staff motivation maintained with:
- Encouragement for training
- Job recognition
- Promotional opportunities
- Salary incentives
- Job security
- Working environment?
Operations
• How are operating schedules established?
• Do schedules attempt to attain optimum staff utilization?
• Are line supervisors included in manpower scheduling?
• Are staff involved in and/or informed of manpower planning?
t Is there sufficient long-term planning for staff replacement
and system changes?
• Are there procedures in manpower staffing for emergency
situations?
• How are process control changes initiated?
NPDES Inspection Manual 4-19 January 1988
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Chapter Four Facility Site Review
Table 4-1
Operations and Maintenance Function Evaluation Questions (Continued)
• How do process control changes interact with management
controls?
t How effectively are laboratory results used in process control?
• Are there emergency plans for treatment control?
• Is there an effective energy management plan? Is the plan
used?
• To what extent are operations personnel involved in the
budget process?
0 Do budgets adequately identify and justify the cost components
of operations?
• Are future budgets based on current and anticipated operating
conditions?
t Do operating and capital budget limits constrain operations?
• Can budget line items be adjusted to reflect actual operating
conditions?
Maintenance
• Are maintenance activities planned? Is the planning formal or
informal?
• Does the facility have sufficient management controls to affect
realistic planning and scheduling? If the controls exist, are
they used?
• Are operating variables exploited to simplify maintenance
efforts?
• To what extent are the supply and spare part inventories
planned in conjunction with maintenance activities?
• Have minimum and maximum levels been established for all
inventory items?
• Does the facility have a maintenance emergency plan?
• Is the maintenance emergency plan current? Is the staff
knowledgeable about emergency procedures?
• Does a plan exist for returning to the preventive maintenance
mode following an emergency?
NPDES Inspection Manual4-20January 1988
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Chapter Four Facility Site Review
Table 4-1
Operations and Maintenance Function Evaluation Questions (Continued)
• Are preventive maintenance tasks scheduled in accordance with
manufacturer's recommendations?
• Is adequate time allowed for corrective maintenance?
• Are basic maintenance practices (preventive and corrective)
and frequencies reviewed for cost-effectiveness?
t Do the management controls provide sufficient information for
accurate budget preparation?
• Does the maintenance department receive feedback on cost
performance to facilitate future budget preparation?
t To what extent are maintenance personnel involved in the
budget process?
t Do budgets adequately identify and justify the cost components
of maintenance?
• Are future budgets based on current and anticipated operating
and maintenance conditions?
• Do maintenance and capital budget limits constrain preventive
maintenance (equipment replacement and improvements)?
• Does the maintenance department receive adequate feedback on
cost performance?
• Can budget line items be adjusted to reflect actual main-
tenance conditions?
Management Controls
• Are current versions of the following documents maintained:
- Operating reports
- Work schedules
- Activity reports
- Performance reports (labor, supplies, energy)
- Expenditure reports (labor, supplies, energy)
- Cost analysis reports
- Emergency and complaint calls
- Process control data, including effluent quality?
t Do the reports contain sufficient information to support their
intended purpose?
NPDES Inspection Manual 4-21 January 1988
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Chapter Four Facility Site Review
Table 4-1
Operations and Maintenance Function Evaluation Questions (Continued)
t Are the reports usable and accepted by the staff?
t Are the reports being completed as required?
• Are the reports consistent among themselves?
• Are the reports used directly in process control?
• Are the reports reviewed and discussed with operating staff?
• What type of summary reports are required?
• To whom are reports distributed and when?
Management Controls (Maintenance)
0 Does a maintenance record system exist? Does it include:
- As-built drawings
- Shop drawings
- Construction specifications
- Capital and equipment inventory
- Maintenance history (preventive and corrective)
- Maintenance costs?
• Is the base record system kept current as part of daily
maintenance practices?
• Is there a work order system for scheduling maintenance? Is
it explicit or implicit?
• Do work orders contain:
- Date
- Work order number
- Location
- Nature of problem
- Work requi rements
- Time requirements
- Assigned personnel
- Space for reporting work performed, required supplies,
time required, and cost summary
- Responsible staff member and supervisory signature
requi rements?
0 When emergency work must be performed without a work order,
is one completed afterward?
• Are work orders usable and acceptable by staff as essential
to the maintenance program? Are they actually completed?
NPDES Inspection Manual 4-22~January 1988
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Chapter Four Facility Site Review
Table 4-1
Operations and Maintenance Function Evaluation Questions (Continued)
t Is work order information transferred to a maintenance record
system?
t Does a catalog or index system exist for controlling items
in inventory?
• Are withdrawal tickets used for obtaining supplies from
inventory?
• Do the tickets contain cost information and interact well with
inventory controls and the work order system?
t Is the cost and activity information from work orders
aggregated to provide management reports? Is this information
also used for budget preparation?
• Is the maintenance performance discussed regularly with staff?
• How is the cost of contract maintenance or the use of
specialized assistance recorded?
t Are safeguards and penalties adequate to prevent maintenance
cards from being returned without the work being done?
• Is the preventive maintenance record checked after an
emergency equipment failure?
NPDES Inspection Manual 4-23 January 1988
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Chapter Four
D REFERENCES AND FACILITY SITE
REVIEW CHECKLIST
References
U.S. Environmental Protection Agency. 1973. Maintenance Management Systems
for Municipal Wastewater Facilities. EPA 430/9-74-004.
U.S. Environmental Protection Agency. 1978. Field Manual for Performance
Evaluation and Troubleshooting at Municipal Wastewater Treatment Facilities.
MO No. 16, EPA 430/9-78-001.
U.S. Environmental Protection Agency. 1979. Inspector's Guide for Evaluation
of Municipal Wastewater Treatment Plants. EPA 430/9-79-010.
U.S. Environmental Protection Agency. 1982. Comprehensive Diagnostic
Evaluation and Selected Management Issues. EPA 430/9-82-003.
Water Pollution Control Federation (WPCF). 1977. Operation of Wastewater
Treatment Plants. MOP No. 11, WPCF, 1977.
Water Pollution Control Federation (WPCF). 1977. Wastewater Treatment Plant
Design. MOP No. 8, WPCF, 1977.
NPDES Inspection Manual4-25January 1988
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Chapter Four
Fad lity Site Review
FACILITY SITE REVIEW CHECKLIST
A. OPERATION AND MAINTENANCE EVALUATION
Yes No N/A
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1.
2.
3.
4.
5.
6.
Treatment units properly operated and maintained.
Standby j)pwer or other equivalent provision provided.
Adequate alarm system for power or equipment failures
avai lable.
Sludge disposal procedures appropriate:
a. Disposal of sludge according to regulations
b. State approval for sludge disposal
received.
All treatment units, other than backup units, in
service.
Procedures for facility operation and maintenance
followed.
7. Sufficient sludge disposed of to maintain treatment
process equilibrium.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Organizational Plan (chart) for operation and mainte-
nance provided.
Operating schedules established.
Emenjency^ pjan for treatment control established.
Maintenance record system exists and includes:
a. As-built drawings
b. Shop drawings
c. Construction specifications
d. Maintenance history
e. Maintenance costs
f. Repair history
g. Records of equipment repair and timely return to
service.
Adequate number of qualified operators on-hand.
Established procedures available for training new
operators.
Adequate spare parts and supplies inventory maintained.
Instruction files kept for operation and maintenance
of each item of major equipment.
Operation and maintenance manual available.
Regulatory agency notified of bypassing.
(Dates )
a. Hydraulic overflows and/or organic overloads
experienced.
b. Untreated bypass discharge occurs during power
fail ure.
c. Untreated overflows occurred since last inspec-
tion. Reason:
d. Flows observed in overflow or bypass channels.
e. Checking for overflows performed routinely.
f. Overflows reported to EPA or to the appropriate
State agency as specified in the permit.
NPDES Inspection Manua'
January 1988
-------
Chapter Four
Facility Site Review
FACILITY SITE REVIEW CHECKLIST
(Continued)
B. SAFETY EVALUATION
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Undiked oil /chemical storage tanks used at facility.
Up-to-date equipment repair records maintained.
Dated tags show out-of-service equipment.
Routine and preventive maintenance scheduled/performed
on time.
Personal protective clothing provided (safety
helmets, ear protectors, goggles, gloves, rubber boots
with steel toes, eyewashes in labs).
Safety devices readily available:
a. Fi re extinguishers
b. Oxygen deficiency/explosive gas indicator
c. Self-contained breathing apparatus near entrance
to chlorine room
d. Safety harness
e. First aid kits
f. Ladders to enter manholes or wetwells (fiberglass
or wooden for electrical work)
g. Traffic control cones
h. Safety buoy at activated sludge plants
i. Life preservers for lagoons
j. Fiberglass or wooden ladder for electrical work
k. Portable crane/hoist.
Plant has general safety structures such as rails
around or covers over tanks, pits, or wells.
Emergency jjhone numbers listed.
Plant is generally clean, free from open trash
areas.
Portable hoists, for equipment removal, available.
All plant personnel immunized for typhoid and
tetanus.
No cross connections exist between a potable water
supply and nonpotable source.
13. Gas/explosion controls such as pressure-vacuum relief
values, no smoking signs, explosimeters, and drip
traps present near anaerobic digesters, enclosed
screening or degritting chambers, and sludge-piping
or gas-piping structures.
14.
Ib.
16.
All electrical circuitry enclosed and identified.
Personnel trained in electrical work to be
performed as well as safety procedures.
Chlorine safety:
a. NIOSH-approved 30-minute air pack
b. All standing chlorine cylinders chained in
place
c. All personnel trained in the use of chlorine
d. Chlorine repair kit available
e. Chlorine leak detector tied into plant alarm
system
NPDES Inspection Manual
4-28
January 1988
-------
Chapter Four
Facility Site Review
FACILITY SITE REVIEW CHECKLIST
(Continued)
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
f. Ventilation fan with an outside switch
g. Posted safety precautions.
17. Facility has complied with the six employer
responsibilities for the Worker Right-to-Know Law
(P.A. 83-240).
18. Emergency Action Plan on file with local fire
department and appropriate emergency agency.
19. Laboratory safety devices (eyewash and shower, fume
hood, proper labeling and storage, pipette suction
bulbs) available.
i iw v\4 9 f* i wf^b i i u ts *~ i i 11^ u i iu .j v vs i u^*» ) {•si^ri.wv^ .j u\* v i vsi i
bulbs) available.
20. Warning signs (no smoking, high voltage, non potable
water, chlorine hazard, watch-your-step, and exit)
osted.
NPDES Inspection Manual
4-29
January 1988
-------
Chapter Five
SAMPLING
Contents Page
A Evaluation of Permittee Sampling Program and Compliance
Sampling
Objectives and Requirements 5-1
Significant Industrial User Monitoring Program 5-2
B Sampling Procedures and Techniques
Sample Collection Techniques 5-3
Selection of Representative Sampling Sites 5-3
Sample Types 5-4
Sample Volume 5-5
Sample Containers 5-6
EPA Sample Identification Methods 5-6
Sample Preservation and Holding Time 5-6
Transfer of Custody and Shipment of Samples 5-7
Quality Control 5-8
Data Handling and Reporting 5-8
C References and Permittee Sampling Inspection Checklist
References 5-23
Permittee Sampling Inspection Checklist 5-25
List of Tables
5-1 Volume of Sample Required for Determination of the Various
Constituents of Industrial Wastewater 5-9
5-2 Compositing Methods 5-12
5-3 Required Containers, Preservation Techniques, Holding
Times, and Test Methods 5-13
List of Figures
5-1 Example Chain-of-Custody Form 5-21
NPDES Inspection Manual5^1January 1988
-------
Chapter Five
A EVALUATION OF PERMITTEE
SAMPLING PROGRAM AND
COMPLIANCE SAMPLING
Wastewater sampling/analysis is an integral part of the National Pollutant
Discharge Elimination System (NPDES) Compliance Monitoring Program. NPDES
permits contain specific and legally enforceable effluent limitations and
monitoring requirements.
Objectives and Requirements
When evaluating the permittee sampling program the inspector should:
• Verify that the permittee's sampling program complies with the
permit
• Verify that the permittee's sampling program complies with 40 CFR
Parts 136.1 to 136.4 and Appendices A, B, and C (Guidelines for
Establishing Test Procedures for the Analysis of Pollutants)
t Document violations to support enforcement action.
In addition, specific objectives of the sampling conducted by inspectors
includes the following:
Verify compliance with daily maximum effluent limitations
Verify accuracy of reports and program self-monitoring
Support enforcement action
Support permit development reissuance and/or revision
Determine the quantity and quality of effluent.
Refer to Chapter Seven for requirements of biomonitoring compliance sampl-
ing. Sampling, analysis, preservation technique, sample holding time, and
sample container requirements are provided under 40 CFR Part 136 as
authorized by Section 304(h) of the Clean Water Act (CWA). More information
on required analytical procedures can be found under "Laboratory Analyses
Techniques Evaluaton" in Chapter Eight. A checklist for use in evaluating
the permittee's sampling program is located at the end of this chapter.
For all NPDES permittees, an evaluation of the permittee sampling program
should include a review of sampling procedures used by the facility and
of quality control measures used to ensure the integrity of sample data.
NPDES Inspection Manual 5-1 January 1988
-------
Chapter Five Sampling
Evaluation of sampling procedures should include an assessment of the
following six areas:
Sample collection techniques
Sample identification
Sample preservation and holding time
Transfer of custody and shipment of samples
Quality control
Data handling and reporting.
Significant Industrial User Monitoring Program
It is the responsibility of the permitted Publicly Owned Treatment Works
(POTW) with a pretreatment program to oversee sampling procedures of
industrial users and to conduct compliance monitoring of its own. There-
fore, in addition to evaluating the sampling procedures of any permitted
POTW (discussed above), the inspector may also need to evaluate POTW
sampling procedures for signficant industrial users who discharge to the
POTW. During a Pretreatment Compliance Inspection (PCI) or an audit,
the inspector evaluates the POTW industrial user monitoring program with
respect to the criteria specified in the POTW pretreatment program.
Elements of the sampling scheme will include the six areas addressed
above and any other areas specifically addressed in the particular pre-
treatment program. Chapter Nine, "Pretreatment," discusses the focus
of this evaluation in greater detail.
NPDES Inspection Manual 5-2 January 1988
-------
Chapter Five
B SAMPLING PROCEDURES AND
TECHNIQUES
Whether an inspector is evaluating a permittee's sampling program or con-
ducting compliance sampling on the permittee's effluent, he/she must be
familiar with the procedures and techniques necessary for accurate sampling
of wastewaters. The following discussion details the procedures for
sample collection, preservation, transfer, quality control, and data
handling.
Sample Collection Techniques
Sample collection is an important part of the compliance monitoring
program. Without proper sample collection procedures, the results of such
monitoring programs are neither useful nor valid, even with the most
precise and accurate analytical measurements.
Selection of Representative Sampling Sites
Samples should be collected at the location specified in the permit. In
some instances, the sampling location specified in the permit or the
location chosen by the permittee may not be adequate for the collection
of a representative sample. In that case, the inspector should determine
the most representative sampling point available and collect a sample at
both locations. The reason for the conflict must be documented for later
resolution by the permitting authority.
Influent Samples. These samples should be taken at points of high-
turbulence flow to ensure good mixing. In some instances, the most
desirable location may not be accessible. Sampling points always should
be above plant return lines and sampling equipment should be placed so that
it does not interfere with flow measuring devices. The preferred sampling
points for raw wastewater are:
t Waste flowing from last process in a manufacturing operation
t Pump wet well (if turbulent)
• Upflow collection lines, tank, or distribution box following
pumping from the wet well or sump
• Flume throat
NPDES Inspection Manual 5-3 January 1988
-------
Chapter Five Sampl ing
• Aerated grit chamber
• Upflow siphon following the comminutor (in absence of grit
chamber).
If it is not possible to sample at a preferred point, an alternative.
location should be chosen and the basis for choosing that location must
be documented.
Effluent Samples. These samples should be collected at the site specified
in the permit or, if no site is specified in the permit, at the most
representative site downstream from all entering wastestreams before they
enter the receiving waters. For some municipal plants, samples should be
collected after chlorination. This will require dechlorination and
reseeding for the Biochemical Oxygen Demand (6005) analysis. Other
municipal plant permits specify sampling prior to chlorination. For these
plants, all parameters can be monitored at the upstream location except
coliforms. Wastewater for use in bioassays should be collected prior to
chlorination.
Samples can be collected either manually (grab or composite) or with
automatic samplers (continuous or composite). The following general
guidelines apply when taking samples:
• Take samples at a site specified in the NPDES permit and/or at a
site selected to yield a representative sample.
• Use a sampling method (grab, composite, continuous) as required
in the sampling and analysis methods of 40 CFR Part 136. Some
parameters that are not to be sampled by automatic samplers, but
must be hand collected samples, include the following: dissolved
oxygen, total residual chlorine, pH, temperature, oil and grease,
coliforms, purgeable organics, and sulfides.
• Avoid collecting large nonhomogeneous particles and objects.
t Collect the sample facing upstream to avoid contamination.
• Do not rinse sample container with sample when collecting oil and
grease and microbiological samples, but fill it directly to within
2.5 to 5 cm from the top.
• Fill the container completely if the sample is to be analyzed
for purgeable organics, oxygen, ammonia, hydrogen sulfide, free
chlorine, pH, hardness, sulfite, ammonium, ferrous iron, acidity,
or alkalinity.
• Collect sufficient volume to allow for quality assurance testing.
(Table 5-1 provides a guide to numerous sample volumes but
additional volumes may be necessary for quality assurance testing.)
Sample Types
Two types of sample techniques are used: grab and composite. For many
monitoring procedures, the sample type is not specified in 40 CFR Part
NPDES Inspection Manual 5-4 January 1988
-------
Chapter Five Sampling
136. For these procedures, the NPDES permit writer determines the
appropriate sample type and these are specified in the NPDES permit.
Grab Samples. Grab samples are individual samples collected over a period
of time not exceeding 15 minutes. Grab samples can be taken manually.
The sample volume depends on the number of analyses to be performed but a
minimum of 2 gallons is recommended for a grab sample and many analyses require
a sample volume of approximately 100 ml. The collection of a grab sample
is appropriate when a sample is needed to:
• Provide information about instantaneous concentrations of pollutants
at a speci fie time
• Allow collection of a variable sample volume
• Corroborate composite samples if waste is not highly variable
• Monitor parameters not amenable to compositing (e.g., pH, temperature,
dissolved oxygen, chlorine, purgeable organics and sulfides, oil
and grease, coliform bacteria and others specified by the NPDES
permit which may include cyanide, phenols, sulfites, hexavalent
chromium, and phosphorus.)
Composite Samples. These samples consist of an appropriate number of
discrete samples collected at equal intervals and combined in proportion
to flow, a sample continuously collected in proportion to flow, or equal
volumes taken at varying time intervals in proportion to flow. A larger
number of discrete samples may be required when flows are highly variable.
Composite samples are used when stipulated in a permit and when:
• Determining average pollutant concentration during the compositing
period
• Calculating mass/unit time loadings
• Wastewater characteristics are highly variable.
Both discreet and composite samples can be collected either manually or with
automatic samplers. Variability in wastestream flow rate and parameter
concentrations should be considered carefully when choosing compositing
methods, sampling equipment (tubing and containers), and quality assurance
procedures.
Compositing samples can be continuous or periodic. There are three
predominant methods for compositing samples which are shown in Table 5-2.
In any manual compositing method, sample handling should be minimized to
reduce the possibility of contamination.
Sample Volume
The volume of samples collected depends on the type and number of analyses
needed, as reflected in the parameters to be measured. The volume of the
sample obtained should be sufficient for all the required analyses plus
an additional amount to provide for any split samples or repeat analyses.
Table 5-1 provides a guide to sample volumes required for determining the
constituents in wastewater. The laboratory receiving the sample should
be consulted for any specific volume required. Specific recommended
minimum sample volumes for different pollutant parameters can be found
in EPA's Methods for Chemical Analysis of Water and Wastes (USEPA 1979b)
NPDES Inspection Manual 5-5 January 1988
-------
Chapter Five Sampling
and Handbook for Sampling and Sample Preservation of Water and Wastewater
(USEPA 1982). and the current EPA-approved edition of Standard Methods
(APHA, AWWA, and WPCF).
Sample Containers
Required sample containers, sample container preparation, and sample
holding techniques are contained in 40 CFR Part 136. A table including
this material is provided in Table 5-3. It is essential that the sample
containers be made of chemically resistant material unaffected by the
concentrations of the pollutants measured. In addition, sample containers
must have a closure that will protect the sample from contamination.
Wastewater samples for chemical analysis generally are collected in
plastic (polyethylene) containers. Exceptions to this general rule are
oil and grease samples, pesticides, phenols, polychlorinated biphenyls
(PCBs), and other organic pollutant samples. These are collected in
properly rinsed glass jars or bottles and sealed. Bacteriological samples
always are collected in properly sterilized plastic or glass containers.
EP/\ Sample Identification Methods
Each sample must be accurately and completely identified. Any label used
to identify the sample must be moisture-resistant and able to withstand
field conditions. A numbered label associated with a field sample data
sheet containing detailed information on the sample is preferable to
using only a label for information. The information provided for each
sample should include the following:
Facility name/location
Sample site description
Sample number
Signature/initials of collector for each sample
Date and time of collection
Indication of grab or composite sample with appropriate time and
volume information
Identification of parameter to be analyzed
Preservative used
Indication of any unusual condition at the sampling location
and/or in the appearance of the wastewater
Notation of conditions such as pH, temperature, residual chlorine,
and appearance that may change before the laboratory analysis,
including the identification numbers of instruments used to
measure parameters in the field.
bample Preservation and Holding Time
In most cases, wastewater samples contain one or more unstable pollutants
that require immediate preservation and/or analysis. Appropriate chemical
preservation should be provided before samples are transferred to the
NPDES Inspection Manual 5-6 January 1988
-------
Chapter Five Sampling
laboratory. Procedures used to preserve samples include icing, refrigeration,
pH adjustment, and chemical treatment. For some parameters such as cyanide
and phenol, preservatives must be added to sample bottles prior to sample
collection. For many samples, if preservatives are not appropriately used,
bacteria can quickly degrade certain constituents (such as phenols and
phosphorus). Other constituents may volatilize (such as cyanide and
sulfides) or may react to form different chemical species (hexavalent
chromium, for example). Proper preservation and holding time for each
parameter of a sample is essential to the integrity of the monitoring
program. (See Table 5-3 and refer to 40 CFR Part 136.)
Prompt analysis is the most positive assurance against error from sample
deterioration, but this is not feasible for composite samples in which
portions may be stored for as long as 24 hours. Where possible, sample
preservation must be provided during compositing, generally by refrigeration
to 4°C (or icing). If an automatic sampler is used with ice, the ice
must be replaced as necessary to maintain low temperatures. This is a
particular limitation of automatic samplers used during the summer when
ice must be frequently replaced.
Transfer of Custody and Shipment of Samples
To ensure the validity of the permit compliance sampling data in court,
written records must accurately trace the custody of each sample through
all phases of the monitoring program. The primary objective of this
chain-of-custody is to create an accurate written record (see Figure 5-1,
an example chain-of-custody form) that can be used to trace the possession
and handling of the sample from the moment of its collection through its
analysis and introduction as evidence.
• Samples should be packed properly to prevent breakage. The
shipping container should be sealed or locked so that any evidence
of tampering may be readily detected. Use of tamperproof evidence
tape is recommended.
• Every sample must be accompanied by either a chain-of-custody tag
or a chain-of-custody record that has been completed, signed, and
dated.
• The responsibility for proper packaging, labeling, and transfer-
ring of possession of the sample lies with the person taking it.
• All sample shipments must be accompanied by the chain-of-custody
record and other pertinent forms. A copy of these forms should
be retained by the originator. Also, all receipts associated
with the shipment should be retained.
• When transferring possession of samples, the transferee must sign
and record the date and time on the chain-of-custody record (use
the currently approved record). In general, custody transfers
are made for each sample, although samples may be transferred as
a group, if desired. Each person who takes custody must fill in
the appropriate section of the chain-of-custody record.
NPDES Inspection Manual5^7January 1988
-------
Chapter Five Sampling
Quality Control
Control checks should be performed during the actual sample collection to
determine the performance of sample collection techniques. In general,
the most common monitoring errors usually are caused by improper sampling,
improper preservation, inadequate mixing during compositing and splitting,
and excessive sample holding time. The following samples should be used
to check sample collection techniques:
• Duplicate samples are separate samples taken from the same source
at the same time. These samples provide a check on sampling
equipment and precision techniques.
• Split samples are samples that have been divided into two containers
for analysis by separate laboratories. These samples provide an
excellent means of identifying discrepancies in the permittee's
analytical techniques and procedures.
• Spiked samples are samples to which a known quantity of substance
has been added. They provide a way to verify the accuracy of the
analytical procedures.
• Sample preservative blanks are samples of distilled water to
which a known quantity of preservative is added. They are analyzed
to determine the effectiveness of the preservative, providing a check
on the contamination of chemical preservatives.
Quality control is discussed in greater detail in Chapter Eight of this
manual.
Data Handling and Reporting
Verified analytical results are normally entered into a laboratory data
management system of some type, which should include sampling data,
including time and exact location, analysis dates and time, names of
analysts, analytical methods/techniques used, and analytical results.
Data are then reported to the project officer (inspector) for inclusion
into the compliance report. The quality assurance manual by EPA (Handbook
for Analytical Quality Control in Water and Wastewater Laboratories.
USEPA 1979) and the article by J.J. Delfino ("Quality Assurance in Water
and Wastewater Analysis Laboratories," Delfino 1977) provide useful
information to the inspector on a number of data management techniques.
NPDES Inspection Manual ^8 January 1988
-------
Chapter Five Sampling
Table 5-1
Volume of Sample Required for Determination of
the Various Constituents of Industrial Wastewater
(Associated Water and Air Resource Engineers, Inc. 1973
Handbook for Monitoring Industrial Wastewater.
USEPA Technology Transfer.)
Tests Volume of Sample,(l) ml
PHYSICAL
Color and Odor(2) 100 to 500
Corrosivity(2) flowing sample
Electrical conductivity(Z) 100
pH, electrometric(2) 100
Radioactivity 100 to 1,000
Specific gravity(Z) 100
Temperature(2) flowing sample
Toxicity(2) 1,000 to 20,000
Turbidity(2) 100 to 1,000
CHEMICAL
Dissolved Gases:
Ammonia,(3) NH(3) 500
Carbon dioxide,(3) free C02 200
Chlorine,(3) free C12 200
Hydrogen,(3) H2 1,000
Hydrogen sulfide,(3) H2S 500
Oxygen,(3) 02 500 to 1,000
Sulfur dioxide,(3) free S02 100
Mi seellaneous:
Acidity and alkalinity 100
Bacteria, iron 500
Bacteria, sulfate-reducing 100
Biochemical oxygen demand (BOD) 100 to 500
Carbon dioxide, total C02 (including C03~~,
HC03", and free) 200
Chemical oxygen demand (dichromate) 50 to 100
Chlorine requirement 2,000 to 4,000
Chlorine, total residual C12 (including OC1",
HOC1, NH2C1, NHC12, and free) 200
Chi oroform-extractable matter 1,000
Detergents 100 to 200
Hardness 50 to 100
Hydrazine 50 to 100
Microorganisms 100 to 200
Volatile and filming amines 500 to 1,000
Oily matter 3,000 to 5,000
Organic nitrogen 500 to 1,000
Phenol ic compounds 800 to 4,000
pH, colorimetric 10 to 20
NPDES Inspection Manual 5-9 January 1988
-------
Chapter Five Sampling
Table 5-1
Volume of Sample Required for Determination of
the Various Constituents of Industrial Wastewater (Continued)
Tests Volume of Sample,(1) ml
Mi seellaneous:
Polyphosphates 100 to 200
Silica 50 to 1,000
Solids, dissolved 100 to 20,000
Solids, suspended 50 to 1,000
Tannin and liynin 100 to 200
Cations:
Aluminum, A1+++ 100 to 1,000
Ammonium,(3) NH4+ 500
Antimony, SD+++ to SD+++++ 100 to 1,000
Arsenic, AS+++ to AS+++++ 100 to 1,000
Barium, Ba++ 100 to 1,000
Cadmium, Cd++ 100 to 1,000
Cal ci urn, Ca++ 100 to 1,000
Chromium, Cr+++ to Cr++++++ 100 to 1,000
Copper, Cu++ 200 to 4,000
Iron,(3) Fe++ and Fe+++ 100 to 1,000
Lead, Pb++ 100 to 4,000
Magne-sium, Mg++ 100 to 1,000
Manganese, Mn++ to Mn+++++++ 100 to 1,000
Mercury, Hg+ and Hg++ 100 to 1,000
Potassium, K+ 100 to 1,000
Nickel, Ni++ 100 to 1,000
Silver, Ag+ 100 to 1,000
Sodium, Na+ 100 to 1,000
Strontium, Sr++ 100 to 1,000
Tin, Sn++ and Sn++++ 100 to 1,000
Zinc, Zn++ 100 to 1,000
An ions:
Bicarbonate, HCO^" 100 to 200
Bromide, Br~ 100
Carbonate, C03" 100 to 200
Chloride, CT* 25 to 100
Cyanide, Cn~ 25 to 100
Fluoride, FT 200
Hydroxide, OH' 50 to 100
Iodide, I- 100
Nitrate, N03" 10 to 100
Nitrite, NO?" 50 to 100
Phosphate, ortho, P04", HP04", H2P04" 50 to 100
NPDES Inspection Manual 5-10 January 1988
-------
Chapter Five Sampling
Table 5-1
Volume of Sample Required for Determination of
the Various Constituents of Industrial Wastewater (Continued)
Tests Volume of Sample,(1) ml
Sulfate, S04", HS04~ 100 to 1,000
Sulfide, S , MS" 100 to 500
Sulfite, S03~~, HS03" 50 to 100
(l)Volumes specified in this table should be considered as guides for the
approximate quantity of sample necessary for a particular analysis.
The exact quantity used should be consistent with the volume prescribed
in the standard method of analysis, whenever a volume is specified.
(2)Aliquot may be used for other determinations.
(3)Samples for unstable constituents must be obtained in separate con-
tainers, preserved as prescribed, completely filled, and sealed against
all exposure.
NPDES Inspection Manual 5-11 January 1988
-------
Chapter Five
Sampling
Table 5-2
Compositing Methods (1)
Compositing
Principle
Volume Constant
Equal Time
Interval (2)
Volume Constant
Variable Time
Interval
Volume Variable
Equal Time
Interval
Advantages
Minimal instrumen-
tation and manual
effort; requires
no fl ow measure-
ment
Minimal manual
effort
Minimal instru-
mentation
Disadvantages
May lack representa-
tiveness, especially
for highly variable
flows
Requi res accurate
flow measurement/
reading equipment;
manual compositing
from flow chart or
totalizer; does not
al low for large
variations in flow
Manual compositing
from flow chart.
Chance of collecting
either too smal 1 or
too large individual
discrete samples for
a given composite
vol ume
Comments
Widely used
in automatic
as wel 1 as
manual
sampling
Widely used
in automatic
sampling and
sometimes
used in
manual
sampling
Widely used
as manual
method and
sometimes
used in
automatic
samplers
(1) For more detailed information, please refer to Table 2-5 of the Handbook
for Sampling and Sample Preservations (EPA 1982), pages 20 and 21.
(2) Not acceptable as flow-weighted composite when flow rates vary by more
than 15 percent during the compositing period.
NPDES Inspection Manua1
5-12
January 1988
-------
Table b-3
Kequlred Containers, Preservation Techniques, Holding Tines, and Test Methods
(Excerpt from 4U CFR Hart 136 Table I and 11)
Parameter
BACTERIAL TESTS
Col i form, fecal and total
Fecal streptococci
INORGANIC TESTS
Acidity
Alkalinity
Ammonia
biochemical oxyyen demand
Biochemical oxygen demand,
carbonaceous
Bromide
Chemical oxygen demand
Chloride
Chlorine, total residual
Color
Container(l)
P.G
P.U
P.li
P.G
P,(i
P,U
P.G
P,G
P.U
P,U
P.G
P,G
Preservati ve(2,3)
Cool, 4°C
0.008* Na^S2U3(6)
Cool, 4°C
0.008% Na2S^U3(6)
Cool, 4°C
Cool, 4°C
Cool, 4°C
H2S04 to pH<2
Cool, 4°C
Cool, 4°C
None requi red
Cool, 4°C
H2SU4 to pH<2
None requi red
None requi red
Cool, 4°C
Maximum
Holding Time(4)
6 hours
6 hours
14 days
14 days
28 days
48 hours
48 hours
28 days
28 days
28 days
Analyze
immediately
48 hours
EPA Test Method
(19?y)
(unless otherwise
noted)
Standard Methods
Ibth Ed.: 908
Standard Methods
Ibth Ed.: 910
30b.l
310.1
3bO
40b.l
Standard Methods
Ibth Ed.:b07(b.e.6)
320.1
410
32b
330
110
o
3-
o>
rl-
n>
-------
Table b-3
Required Containers, Preservation Techniques, Holding Times, and Test Methods
(Excerpt from 40 CFR Part 136 Table I and II) (Continued)
o
3-
o
Parameter
Cyanide, total and amenable
to chlorination
Fluoride
Hardness
Hydrogen ion (pH)
Kjeldahl and organic nitrogen
METALS(7)
Chromium VI
Mercury
Metals except above
Nitrate
Nitrate-nitrite
Nitrite
Oil and grease
Organic carbon
Container(l)
P.G
P
P.G
P.G
P.G
P.G
P.G
P.G
P.G
P.G
P.G
G
P.G
Preservati ve(2,3)
Cool, 4°C
NaUH to pH>12
0.6 g ascorbic acid(t>)
None requi red
HN03 to pH<2. H2S04
to pH<2
None requi red
Cool, 4°C
Hi)S04 to pH<2
Cool, 4°C
HN03 to pH<2
HNu3 to ^H<2
Cool, 4°C
Cool, 4°C
H2S04 to pH<2
Cool, 4°C
Cool, 4°C
HzS04 to pH<2
Cool, 4°C HC1 or
Hi>S04 to pH<2
Maximum
Holding Time(4)
14 days(6)
28 days
6 months
Analyze
immediately
28 days
24 hours
28 days
6 months
48 hours
28 days
48 hours
28 days
28 days
EPA Test Method
(1979)
(unless otherwise
noted)
335
340
130
150.1
351
218.4
24b
(Various EPA
Methods)
352.1
353
354
413
415
-------
Table 5-3
Required Containers, Preservation Techniques, Holding Times, and Test Methods
(Excerpt from 40 CFR Part 136 Table I and 11)(Continued)
Parameter
Orthophosphate phosphorus
Dissolved oxygen
Probe
Winkler
Phenols
Phosphorus (elemental )
Phosphorus, total dissolved
Residue, total
Residue, filterable
Residue, nonf llterable (TSS)
Residue, settleable
Residue, volatile
Silica
Specific conductance
Sulfate
Cental ner(l)
P,G
G bottle & top
G bottle & Top
G
G
P.G
P,G
P.G
P.6
P.6
P.G
P
P.G
P.G
Preservative(2, 3)
Filter Immediately
Cool, 4°C
None required
Fix on-site and
store in the dark
Cool, 4°C
H2S04 to pH<2
Cool, 4°C
Cool, 4°C
H2S04 to pH<2
Cool. 4°C
Cool, 4°C
Cool. 4°C
Cool, 4°C
Cool. 4°C
Cool. 4°C
Cool, 4°C
Cool. 4°C
Maximum
Holding Time(4)
48 hours
Analyze immediately
8 hours
24 hours
48 hours
28 days
7 days
7 days
7 days
48 hours
7 days
28 days
28 days
28 days
EPA Test Method
(1979)
(unless otherwise
noted)
365
360
420
Note (16)
365
160.3
160.1
160.2
160.5
160.4
370.1
120.1
375
r
3
o>
rt
fD
<
(D
Oi
§
-------
Table 5-3
Required Containers, Preservation Techniques, Holding Times, and Test Methods
(Excerpt from 40 CFR Part 136 Table I and II )(Continued)
o
3-
o>
Parameter
Sulfide
Sulflte
Surfactants
Temperature
Turbidity
ORGANIC TESTS (8)
Purgeable halocarbons
Purgeable aromatic hydrocarbons
Acroleln and acrylonltrlle
Phenols
Container(l)
P.G
P.G
P.G
P.G
P.G
G, teflon-
lined septum
G, teflon-
lined septum
G, teflon-
lined septum
G. teflon-
lined cap
Preservative(2, 3)
Cool , 4°C add
zinc acetate plus
sodium hydroxide
pH >9
None required
Cool, 4°C
None requi red
Cool, 4°C
Cool, 4°C
0.008% Na2S203(5)
Cool, 4°C
0.008% Na2S?03(5)
HC1 to pH 2(9)
Cool. 4°C
0.008% Na2S203(5)
Adjust pH to 4.5(10)
Cool, 4°C
0.008% Na2S203(5)
Maximum
Holding T1me(4)
7 days
Analyze
Immediately
48 hours
Analyze
immediately
48 hours
14 days
14 days
14 days
7 days until
extraction; 40
days after
extraction
EPA Test Method
(1979)
(unless otherwise
noted)
376
377
425.1
170.1
180.1
601 (40 CFR
Appendix A,
1984)
602 (40 CFR
Appendix A,
1984)
603 (40 CFR
Appendix A,
1984)
604 (40 CFR
Appendix A,
1984)
136
136
136
136
-------
Table 5-3
Required Containers, Preservation Techniques, Holding Times, and Test Methods
(Excerpt from 40 CFR Part 136 Table I and II) (Continued)
Parameter
Benzldenes(ll)
Phthalate esters(ll)
Nitrosamines(ll,14)
Polychlorlnated biphenyls
(PCBs)(ll)
Nitroaromatics and isophorone(ll)
Polynuclear aromatic hydrocarbons (11)
Haloethers(ll)
Container(l)
G, teflon-
lined cap
G, teflon-
lined cap
G, teflon-
lined cap
G. teflon-
lined cap
G, teflon-
lined cap
G, teflon-
lined cap
G, teflon-
lined cap
Preservative^, 3)
Cool, 4°C
0.008% Na2S203(5)
Cool, 4°C
Cool, 4°C
Store in the dark
0.008% Na2$203(5)
Cool, 4°C
Cool, 4°C
0.008% Na2$203(5)
Store In the dark
Cool, 4°C
0.008% Na2$203(5)
Store In the dark
Cool, 4°C
0.008% Na2S203(5)
Maximum
Holding T1me(4)
7 days until
extraction(13)
7 days until
extraction;
40 days after
extraction
7 days until
extraction;
40 days after
extraction
7 days until
extraction;
40 days after
extraction
7 days until
extraction;
40 days after
extraction
7 days until
extraction;
40 days after
extraction
7 days until
extraction;
40 days after
extraction
EPA Test Method
(1979)
(unless otherwise
noted)
605 (40 CFR 136
Appendix A,
1984)
606 (40 CFR 136
Appendix A,
1984)
607 (40 CFR 136
Appendix A,
1984)
608 (40 CFR 136
Appendix A,
1984)
609 (40 CFR 136
Appendix A,
1984)
610 (40 CFR 136
Appendix A,
1984)
611 (40 CFR 136
Appendix A,
1984)
o
=r
01
o
rl-
n>
-------
Table 5-3
Required Containers, Preservation Techniques, Holding Times, and Test Methods
(Excerpt from 40 CFR Part 136 Table I and II) (Continued)
Parameter
Chlorinated hydrocarbons(ll)
TCDD (2.3,7.8-Tetrachlorodlbenzo-
p-Dioxin)(ll)
PESTICIDES TEST
Organochlorine pesticldes(ll)
Alpha, beta
RADIOLOGICAL TEST
, and radium
Container(l)
G, teflon-
lined cap
G, teflon-
lined cap
G, teflon-
lined cap
P.6
Preservative(2,3)
Cool. 4°C
Cool, 4°C
0.008% Na2S203(5)
Cool, 4°C
pH 5-9(15)
HN03 to pH<2
Maximum
Holding T1me(4)
7 days until
extraction;
40 days after
extraction
7 days until
extraction;
40 days after
extraction
7 days until
extraction;
40 days after
extraction
6 months
EPA Test Method
(1979)
(unless otherwise
noted)
612 (40 CFR 136
Appendix A,
1984)
613 (40 CFR 136
Appendix A,
1984)
608 (40 CFR 136
Appendix A,
1984)
Method 900-903(17)
o
Bl
o
n>
(l)Polyethylene (P) or glass (G).
(2)Sample preservation should be performed Immediately upon sample collection. For composite chemical samples each
aliquot should be preserved at the time of collection. When use of an automatic sampler makes It impossible to
preserve each aluqiot, then chemical samples may be preserved by maintaining at 4*C until compositing and sample
splitting In completed.
(3)Uhen any sample Is to be shipped by common carrier or sent through the United States mall, it must comply with the
Department of Transportation Hazardous Materials Regulations (49 CFR Part 172). The person offering such
material for transportation Is responsible for ensuring such compliance. For the preservation requirements of
this Table, the Office of Hazardous Materials. Materials Transportation Bureau, Department of Transportation has
determined that the Hazardous Materials Regulations do not apply to the following materials: hydrochloric acid (HC1)
1n water solutions at concentrations of 0.04% by weight or 1esS^fptt'about 1.96 or greater); nitric acid (HN03) in
water solutions at concentrations of 0.15% by weight or less (pH about 1.62 or greater); sulfuric acid (H2S04) in
water solutions at concentrations of 0.35% by weight or less (pH about 1.15 or greater); and sodium hydroxide (NaOH) in
water solutions at concentrations of 0.80% by weight or less (pH about 12.30 or less).
o>
3
10
-------
Table 5-3
Required Containers, Preservation Techniques, Holding Times, and Test Methods
(Excerpt from 40 CFR Part 136 Table I and II) (Continued)
(4)Samples should be analyzed as soon as possible after collection. The times listed are the maximum times that samples
may be held before analysis and still be considered valid. Samples may be held for longer periods only If the permit-
tee, or monitoring laboratory, has data on file to show that the specific types of samples under study are stable for
the longer time and has received a variance from the Regional Administrator under § 136.3(e). Some samples may not
be stable for the maximum time period given 1n the table. A permittee, or monitoring laboratory, is obligated to
hold the sample for a shorter time If knowledge exists to show this is necessary to maintain sample stability.
(b)Should only be used 1n the presence of residual chlorine.
(6)Max1mum holding time Is 24 hours when sulflde 1s present. Optionally, all samples may be tested with lead acetate
paper before pH adjustments to determine If sulflde 1s present. If sulfide is present, it can be removed by the
addition of cadmium nitrate powder until a negative spot test is obtained. The sample is filtered, then NaOH is
added to pH 12.
(7)Samples should be filtered Immediately on-site before adding preservative for dissolved metals.
(8)Gu1dance applies to samples to be analyzed by GC, LC, or GC/MS for specific organic compounds.
(9)Sample receiving no pH adjustment must be analyzed within 7 days of sampling.
(10)The pH adjustment 1s not required If acroleln will not be measured. Samples for acrolein receiving no pH adjustment
must be analyzed within 3 days of sampling.
(ll)When the extractable analytes of concern fall within a single chemical category, the specified preservation and maxi-
mum holding times should be observed for optimum safeguarding of sample Integrity. When the analytes of concern fall
within two or more chemical categories, the sample may be preserved by cooling to 4°C, reducing residual chlorine with
0.008Y sodium thlosulfate, storing In the dark, and adjusting the pH to 6-9; samples preserved in this manner may be
held for 7 days before extraction and for 40 days after extraction. Exceptions to this optional preservation and
holding time procedure are noted In footnote (5) (re: the requirement for thlosulfate reduction of residual chlorine)
and footnotes (12), (13) (re: the analysis of benzldlne).
-------
Table 5-3
Required Containers. Preservation Techniques, Holding Times, and Test Methods
(Excerpt from 40 CFR Part 136 Table I and II) (Continued)
(12)lf !,2-d1phenylhydraz1ne Is likely to be present, adjust the pH of the sample to 4.0 +_ 0.2 to prevent rearrangement of
benzldlne.
(13)Extracts nay be stored up to 7 days before analysis If storage Is conducted under an Inert (oxidant-free) atmosphere.
(14)For the analysis of dlphenylnltrosamlne. add 0.0081 Na2S203 and adjust pH to 7-10 with NaOH within 24 hours of
sampling.
(15)The pH adjustment may be performed upon receipt at the laboratory and may be omitted if the samples are extracted
within 72 hours of collection. For the analysis of aldMn. add 0.0081 Na2S03.
(16)K.F. Addlson and R.G. Ackman. "Direct Determination of Elemental Phosphorus by Gas-Liquid Chromatography." Journal of
Chromatography. 47 (3): 421-426, 1970.
(17Reference: "Prescribed Procedures for Measurement of Radioactivity 1n Drinking Water" EPA-600/4-80-032 (1980 update)
USEPA. August 1980.
-------
Chapter Five
Sampling
SAMPLING RECORD
Person Sampling:
Date:
Facility Sampled:
Facility Location:
Sampling Location:
Sample Type:
Observation/Comments:
Time:
am/ptn
Grab ( )
Composite ( )
Sample Bottle I.D. (marking)
Samples split with facility?
Name of Facility Representing:
Yes ( )
No ( )
Title of Facility Representing:
TIME/DATE
SAMPLE
RECEIVED BY
AFFILIATION/
TITLE
COMMENTS
Figure 5-1
Example Chain-of-Custody Form
NPDES Inspection Manual
January 1988
-------
Chapter Five
C REFERENCES AND PERMITTEE
SAMPLING INSPECTION CHECKLIST
References
APHA, AWWA, and WPCF. Standard Methods for the Examination of Water and
Wastewater. Use the most current, accepted edition.
Associated Water and Air Resources Engineers, Inc. 1973. Handbook for
Industrial Wastewater Monitoring, USEPA Technology Transfer.
Code of Federal Regulations. 1985. Title 40, Part 136.31. Office of the
Federal Register.
Delfino, J.J. 1977. "Quality Assurance in Water and Wastewater Analysis
Laboratories." Water and Sewage Works, 124(7): 79-84.
Federal Register, Vol. 49, No. 209, October 26, 1984. Guidelines
Establishing Test Procedures for the Analysis of Pollutants Under the
Clean Water Act; Final Rule and Interim Final Rule and Proposed RuleT"
Harris, D.J., and Keffer, W.J. 1974. Wastewater Sampling Methodologies
and Flow Measurement Techniques. U.S. Enviromnental Protection Agency
Region VII, EPA-907/9-74-005, Kansas City, Missouri.
Lauch, R.P. 1975. Performance of ISCO Model 1391 Water and Wastewater
Sampler. U.S. Environmental Protection Agency, EPA-670/4-75-003,
Cincinnati, Ohio.
Lauch, R.P. 1976. A Survey of Commercially Available Automatic Wastewater
Samplers. U.S. Environmental Protection Agency, EPA-600/4-76-051,
Cincinnati, Ohio.
Shelley, P.E. 1975. Design and Testing of a Prototype Automatic Sewer
Sampling System. Office of Research and Development, U.S. Environmental
Protection Agency, EPA 600/2-76-006, Washington, D.C.
Shelley, P.E., and Kirkpatrick, G.A. 1975. An Assessment of Automatic
Sewer Flow Samplers. Office of Research and Development, U.S. Environmental
Protection Agency, EPA-600/2-75-065, Washington, D.C.
NPDES Inspection Manual5-23January 1988
-------
Chapter Five Sampling
U.S. Environmental Protection Agency. 1978. Methods for Benzidine,
Chlorinated Organic Compounds, Pentachlorophenol and Pesticides in Water
and Wastewater. Environmental Monitoring and Support Laboratory,
Ci nci nnati , Ohio.
U.S. Environmental Protection Agency. 1979a. Handbook for Analytical
Quality Control in Water and Wastewater Laboratories"! EPA-600/4-79-019.
U.S. Environmental Protection Agency. 1979b. Methods for Chemical
Analysis of Uater and Wastes. EPA-600/4-79-020, Washington, D.C.
U.S. Environmental Protection Agency. 1981. Methods for Organic Chemical
Analysis of Water and Wastes by GC, HPLC and GC/MS.Environmental
Monitoring Support Laboratory, Cincinnati, Ohio.
U.S. Environmental Protection Agency. 1982. Handbook for Sampling and
Sample Preservation of Water and Wastewater. EPA-600/4-82-029, Cincinnati,
Ohio.
Wood, L.B., and Stanbridge, H.H. 1968. "Automatic Samplers," Water
Pollution Control , 67(5): 495-520.
NPDES Inspection Manual5-24January 1988
-------
Chapter Five
Sampling
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
B.
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
PERMITTEE SAMPLING INSPECTION CHECKLIST
A. PERMITTEE SAMPLING EVALUATION
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Samples taken at sites specified in permit.
Locations adequate for representative samples.
Flow proportioned samples obtained when required by
permit.
Sampling and analysis completed on parameters specified
by permit .
Sampling and analysis done in frequency specified by
permit.
Permittee uses method of sample collection required by
permit.
Requi red method:
If not, method being used is: ( ) Grab ( ) Manual
composite ( ) Automatic composite
Sample collection procedures adequate:
a. Samples refrigerated during compositing
b. Proper preservation techniques used
c. Containers and sample holding times before analyses
conform to 40 CFR Part 136.3
d. Samples analyzed in timeframe needed (same day,
etc.).
Monitoring and analyses performed more often than
required by permit. If so, results reported in
permittee's self-monitoring report.
Samples contain chlorine.
Contract laboratory used for sample analysis.
POTW collects samples from industrial users in
pretreatment program.
SAMPLING INSPECTION PROCEDURES AND OBSERVATIONS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Grab samples obtained.
Composite sample obtained.
Compositing frequency: Preservation:
Sample refrigerated during compositing.
Flow proportioned sample obtained.
Sample obtained from facility sampling device.
Sample representative of volume and nature of discharge.
Sample split with permittee.
Chain-of-custoo^y procedures employed.
Samples collected in accordance with permit.
Excessive foam, grease, floating solids observed at
the outfall .
NPDES Inspection Manual
5-25
January 1988
-------
Chapter Six
FLOW MEASUREMENT
Contents Page
A Evaluation of Permittee's Flow Measurement
Objectives and Requirements 6-1
Evaluation of Facility Installed Flow Devices and Data 6-1
Evaluation of Permittee Data Handling and Reporting 6-3
Evaluation of Permittee Quality Control 6-4
B Supplementary Information
Basic Hydraulic Calculations 6-5
Flow Measurement Devices 6-5
Primary Devices 6-6
Secondary Devices 6-9
Pumps 6-10
C Flow Measurement Compliance
Objectives 6-29
Flow Measurement System Evaluation 6-29
Primary Device Inspection Procedures 6-30
Sharp-Crested Weir Inspection Procedures 6-31
Parshall Flume Inspection Procedures 6-32
Palmer-Bowlus Flume Inspection Procedures 6-32
Venturi Meter Inspection Procedures 6-33
Secondary Device Inspection Procedures 6-33
Flow Measurement in Weir Applications 6-33
Flow Measurement in Parshall Flume Applications 6-34
Flow Measurement in Palmer-Bowlus Flume Applications 6-35
Verification 6-35
D References and Flow Measurement Inspection Checklist
References 6-37
Flow Measurement Inspection Checklist 6-39
NPDES Inspection Manual 6-i January 1988
-------
Chapter Six Contents
List of Tables
6-1 Head-Discharge Relationship Formulas for
Nonsubmerged Weirs 6-11
6-2 Discharge of 90° V-Notch Weir - Head Measured
at Weir Plate 6-12
6-3 Minimum and Maximum Recommended Flow Rates for Cipolletti
Weirs 6-13
6_4 Minimum and Maximum Recommended Flow Rates for Free Flow
Through Parshall Flumes 6-13
6-5 Free-Flow Values of C and N for Parshall Flume Based
on the Relationship Q = CWHan 6-14
6-6 Minimum and Maximum Recommended Flow Rates for Free
Flow Through Plasti-Fab Palmer-Bowlus Flumes 6-15
6-7 Coefficients of Discharge c for Venturi Meters 6-16
6-8 Values of K in Formula for Venturi Meters 6-16
6-9 Advantages and Disadvantages of Secondary Devices 6-17
List of Figures
6-1 Profile and Nomenclature of Sharp-Crested Weirs 6-19
6-2 Three Common Types of Sharp-Crested Weirs 6-20
6-3 Flow Rates for 60° and 90° V-Notch Weirs 6-21
6-4 Nomograph for Capacity of Rectangular Weirs 6-22
6-5 Flow Curves for Parshall Flumes 6-23
6-6 Dimensions and Capacities of Parshall Measuring
Flume for Various Throat Widths 6-24
6-7 Effect of Submergence on Parshall Flume Free Discharge ... 6-26
6-8 Free Flowing Palmer-Bowlus Flume 6-27
6-9 Configuration and Nomenclature of Venturi Meter 6-27
6-10 Electromagnetic Flowmeter 6-28
6-11 Propeller Flowmeter 6-28
NPDES Inspection Manual 6-ii January 1988
-------
Chapter Six
A EVALUATION OF PERMITTEE'S
FLOW MEASUREMENT
Objectives and Requirements
To comply with the permit requirements established under the National
Pollutant Discharge Elimination System (NPDES), the permittee must accu-
rately determine the quantity of wastewater being discharged. Therefore,
discharge flow measurement is an integral part of the NPDES program and
the accuracy of the measurement must be evaluated by the inspector.
In addition to providing usable information for enforcement purposes,
flow measurement serves to:
• Provide operating and performance data on the wastewater treatment
plant
t Compute treatment costs, based on wastewater volume
• Obtain data for long-term planning of plant capacity, versus
capacity used.
A Flow Measurement Inspection Checklist for the inspector's use appears
at the end of this chapter.
Evaluation of Facility Installed Flow Devices and Data
Two types of wastewater flow can be encountered: closed channel flow and
open channel flow. Closed channel flow occurs under pressure in a liquid-
full conduit (usually a pipe). Flow in closed channels is usually measured
by a metering device inserted into the conduit. Examples of closed chan-
nel flow measuring devices are the Venturi meter, the pitot tube, and the
electromagnetic flowmeter. In practice, closed channel flow is normally
encountered only between treatment units in a wastewater treatment plant,
where liquids and/or sludges are pumped under pressure.
Open channel flow occurs in conduits that are not liquid-full. Partially
full pipes, not under pressure, are classified as open channels. Open
channel flow is the most prevalent type of flow at NPDES-regulated
discharge points.
NPDES Inspection Manual 6-1 January 1988
-------
Chapter Six Flow Measurement
Open channel flow is measured using primary and secondary devices.
Primary devices are calibrated hydraulic structures, such as flumes and
weirs, that are inserted in the open channel. Accurate flow measurements
can be obtained merely by measuring the depth of liquid (head) at the
specific point in the primary device. In a weir application, for example,
the flow rate is a function of the head of liquid above the weir crest.
Secondary devices are used in conjunction with primary devices to automate
the flow measuring process. Typically, secondary devices measure the
liquid depth in the primary device and convert the depth measurement to a
corresponding flow, using established mathematical relationships. Examples
of secondary devices are floats, ultrasonic transducers, and bubblers.
The output of the secondary device generally is transmitted to a recorder
and/or totalizer to provide instantaneous and historical flow data to the
operator. Outputs may also be transmitted to sampling systems to facilitate
flow-proportioning.
The permittee must obtain accurate wastewater flow data to calculate mass
loading (quantity) from measured concentrations of pollutants discharged as
required by many NPDES permits. The permittee must produce data that
meet requirements in terms of precision and accuracy. Precision refers
to data reproducibility or the ability to obtain consistent data from
repeated measurements of the same quantity. Accuracy refers to the
agreement between the amount of a component measured by the test and the
amount actually present.
The accuracy of flow measurement (including both primary and secondary
devices) varies widely with the device, its location, environmental
conditions, and other factors such as maintenance and calibration. Faulty
fabrication, construction, and installation of primary devices are common
sources of errors. Improper calibration, misreading, and variation in
the speed of totalizer drive motors are major errors related to secondary
devices.
When evaluating facility installed devices, the inspector should:
0 Verify that the primary and secondary devices have been installed
according to manufacturer's instructions and other applicable
plans and specifications.
• Inspect the primary device for evidence of corrosion, scale forma-
tion, or solids accumulation that may bias the flow measurement.
• Verify that weirs are level, plumb, and perpendicular to the flow
direction.
• Verify that flumes are level, the throat walls are plumb, and the
throat width is the standard size intended.
• Inspect historical records (strip charts, logs, etc.) for evidence
of continuous flow measurements. Compare periods of missing data
with maintenance logs for explanations of measuring system
problems.
NPDES Inspection Manual5^2January 1988
-------
Chapter Six Flow Measurement
• Observe the flow patterns near the primary device for excessive
turbulence or velocity. The flow lines should be straight.
• Ensure that the flow measurement system or technique being used
measures the entire wastewater discharge as required by the NPDES
permit. A careful inspection should be conducted to determine
whether there are any wastewater diversions or bypasses around
the system. Make sure the system meets the permit requirement,
such as instantaneous or continuous, daily or other time interval.
Anomalies should be reported on the inspection form.
• Verify that the site chosen for flow measurement is appropriate
and is in accordance with permit requirements.
• Verify that the site chosen for flow measurement is suitable for
type of discharge, flow range, suspended solids concentration,
and other relevant factors.
t Verify that tables, curves, and formulas are appropriate and are
used correctly to calculate flow rates.
• Review and evaluate calibration and maintenance programs for the
discharger's flow measurement system. The permit normally requires
that calibration be checked regularly by the permittee. The cali-
bration of flow measurement systems must be checked often enough
to ensure their accuracy. Lack of such a program is considered
unacceptable for NPDES compliance purposes.
• Verify that primary and secondary devices are adequate for normal
flow as well as maximum expected flow. Note whether the flow
measurement system can measure the expected range of flow.
• Collect accurate flow data during inspection to validate self-
monitoring data collected by the permittee.
Evaluation of Permittee Data Handling and Reporting
The permittee or facility must keep flow measurement records for a minimum
period of three years as the permit requires. Many flow measuring devices
produce a continuous flow chart for plant records. Flow records should
contain date, flow, time of reading, and operator's name, if applicable.
Maintenance, inspection dates, and calibration data should also be recorded,
The inspector should review the permittee's records and note the presence
or absence of data such as:
§ Frequency of routine operational inspections
• Frequency of maintenance inspections
• Frequency of flowmeter calibration
• Irregularity or uniformity of flow.
NPDES Inspection Manual 6-3 January 1988
-------
Chapter Six Flow Measurement
Evaluation of Permittee Quality Control
The following quality control issues should be evaluated carefully during
a compliance inspection:
Proper operation and maintenance of equipment
Accurate records
Sufficient inventory of spare parts
Valid flow measurement techniques
Preci se flow data
Adequate frequency of calibration checks.
Precision can be evaluated at float driven devices when flows are stable.
The float is pushed gently downward, held for 30 seconds, then allowed to
return normally. The recorded flow rate should be the same before and
after the float was moved. Accuracy can be evaluated by measuring the
instantaneous flow rate at the primary device used at the facility and
comparing the value against the value on the meter, graph, integrator, or
company record. The difference between two stable totalizer readings
(flow is steady for 10 minutes or more) should not exceed + 10 percent of
the instantaneous flow measured at the primary device.
Accuracy can also be evaluated by installing a second flow measurement system,
sometimes referred to as a reference system. Agreement in measured flow
rates between the two systems should be within +10 percent of the reference
rate if all conditions are as recommended for the systems.
NPDES Inspection Manual5^3January 1588
-------
Chapter Six
B SUPPLEMENTARY INFORMATION
Basic Hydraulic Calculations
The relationship between the flow rate (Q), the average velocity (V) and
the cross-sectional area of the flow (A) is given by the following
equation:
Q = VA
Q is flow in cubic feet per second
V is velocity in feet per second
A is area in square feet
To convert flow in cubic feet of water per second to flow in gallons of
water per minute, the following proportionality is used:
cubic feet x 7.48 gallons water x 60 seconds = gallons
second cubic foot of water minute minute
To convert from cubic feet per second to million gallons per day, multiply
the number of cubic feet per second by 0.6463.
The cross-sectional area (A) of a pipe is described by:
A = 1/4 7i d^ , where d is the diameter of the pipe in feet
Flow Measurement Devices
Flow data may be collected instantaneously or continuously. Instantaneous
flows must be measured when samples are taken so that the pollutant concen-
trations can be correlated to flow data. In a continuous flow measurement
system, flow measurements are summed to obtain a value for the total flow
to verify NPDES permit compliance.
A typical continuous flow measurement system consists of a flow device,
a flow sensor, transmitting equipment, a recorder, and a totalizer.
NPDES Inspection ManualttJanuary 1988
-------
Chapter Six Flow Measurement
Instantaneous flow data can be obtained without using such a system. The
primary flow device is constructed to yield predictable hydraulic responses
related to the rate of wastewater or water flowing through the device.
As previously mentioned, examples of such devices include weirs and
flumes, which relate water depth (head) to flow; Venturi meters, which
relate differential pressure to flow; and electromagnetic flow meters,
which relate induced electric voltage to flow. In most cases, a standard
primary flow device has undergone detailed testing and experimentation
and its accuracy has been verified.
Flow is measured by many methods; some are designed to measure open channel
flows, others are designed to measure flows in pipelines. A complete
discussion of all available flow measurement methods, their supporting
theories, and the devices used are beyond the scope of this manual. The
most commonly used flow measurement devices and procedures for inspecting
them will be described briefly in the following paragraphs. For more
detail, inspectors should consult the publications listed in "References"
at the end of this chapter.
Primary Devices
Weirs. A weir consists of a thin vertical plate with a sharp crest that
is placed in a stream, channel, or partly filled pipe. Figure 6-1 shows
a profile of a sharp-crested weir and indicates the appropriate nomenclature.
Four common types of sharp-crested weirs are shown in Figure 6-2. This
figure illustrates the difference between supressed and contracted
rectangular weirs as well as illustrates Cipolletti (trapezoidal) and
V-notch (triangular) weirs.
To determine the flow rate, it is necessary to measure the hydraulic head
(height) of water above the crest of the weir. For accurate flow measure-
ments, the crest must be clean, sharp, and level. The edge of the crest
must not be thicker than 1/8 inch.
The rate of flow over a weir is directly related to the height of the
water (head) above the crest at a point upstream of the weir where the
water surface is level. To calculate the discharge over a weir, the head
must first be measured by placing a measuring device upstream of the
weir, at a distance of at least 4 times an approximate measurement of the
head. A measurement can be taken at the weir plate to approximate the
head. However, if this measurement is used to calculate the discharge,
this value will provide only a rough estimate of the discharge.
The head-discharge relationship formulas for nonsubmerged contracted and
suppressed rectangular weirs, Cipolletti weirs, and V-notch weirs are
provided in Table 6-1. Discharge rates for the 90-degree V-notch weir
(when the head is measured at the weir plate) are included in Table 6-2.
Flow rates for 60- and 90-degree V-notch weirs can be determined from the
nomograph in Figure 6-3. Minimum and maximum recommended flow rates for
Cipolletti weirs are provided in Table 6-3. Figure 6-4 is a nomograph
for flow rates for rectangular weirs using the Francis formulas.
NPDES Inspection Manual 6-6 January 1988
-------
Chapter Six Flow Measurement
Parshall Flume. The Parshall flume is composed of three sections: a
converging upstream section, a throat or contracted section, and a
diverging or dropping downstream section. When there is free fall out of
the throat of a Parshall flume, no diverging downstream section is required.
It operates on the principle that when open channel water flows through a
constriction in the channel, it produces a hydraulic head at a certain
point upstream of the constriction that is proportional to the flow. The
hydraulic head is used to calculate the flow. Flow curves are shown in
Figure 6-5 to determine free flow through 3 inches to 50 feet Parshall
flumes.
The Parshall flume is good for measuring open channel waste flow because
it is self cleaning; therefore, sand or suspended solids are unlikely to
effect the operation of the device. The flume is both simple and accurate.
The flume size is given by the width of the throat section. Parshall
flumes have been developed with throat widths from 1 inch to 50 feet.
The configuration and standard nomenclature for Parshall flumes is provided
in Figure 6-6. Strict adherence to all dimensions is necessary to achieve
accurate flow measurements. Figure 6-6 provides Parshall flume dimensions
for various throat widths and Table 6-4, provides the minimum and maximum
flow rates for free flow through Parshall flumes.
For free nonsubmerged flow in a Parshall flume of throat and upstream
head (Ha in feet), the discharge relationship for flumes of 8 feet or
less is given by the general equation Q = CWHan, where Q = flow.
Table 6-5 provides the values of C, n, and Q for different sizes (widths)
of the Parshall flumes. Nomographs, curves, or tables are readily available
to determine the discharge from head observations.
Flow through a Parshall flume may also be submerged. The degree of sub-
mergence is indicated by the ratio of the downstream head to the upstream
head (Hb/Ha) which is the submergence ratio. Hb is the height of water
measured above the crest. The flow is submerged if the submerged ratio is:
• Greater than 0.5 for flumes under 3 inches
t Greater than 0.6 for flumes 6 to 9 inches
t Greater than 0.7 for flumes 1 to 8 feet
• Greater than 0.8 for flumes larger than 8 feet.
If submerged conditions exist, the inspector should apply a correction
factor to the free flow determined using the relationship Q= CWHn. These
correction factors are shown in Figure 6-7 for different sizes of the
Parshall flume.
Palmer-Bowl us Flume. The Palmer-Bowl us flume is also composed of three
sections: a converging upstream section, a contracted section or throat,
and a diverging downstream section (Figure 6-8). The upstream depth of
the water (head) above the raised step in the throat is related to the
discharge rate. The head should be measured a distance d/2 upstream of
the throat where d is the size (width) of the flume. The height of the
step is ususally unknown until the manufacturer's data is consulted, it
is difficult to manually measure the height of water above the step at an
upstream point. The dimensions for Palmer-Bowlus flumes are not standardized
NPDES Inspection Manual 6-7 January 19138
-------
Chapter Six _ Flow Measurement
as they are for Parshall flumes. Therefore, no standard flow equation
exists. Instead, rating curves are provided by manufacturers of Palmer-
Bowlus flumes to relate the head to the discharge rate.
The flume must be installed with a minimum channel slope downstream to
maintain critical flow through the flume and prevent the flume from becoming
submerged. A small jump or rise in the water surface below the throat
indicates that critical flow through the flume has probably occurred and
submerged conditions exist. Accurate flow measurements can usually be
obtained with upstream depths that are up to 95 percent of the pipe
diameter. Table 6-6 provides a table of the maximum slopes recommended
for installation of Palmer-Bowlus flumes.
Advantages of this type of flow measurement device are:
• It is easily installed in existing systems
• Head loss is insignificant
• Unit is self cleaning.
Venturi Meter. The Venturi (differential pressure) meter is one of the
most accurate primary devices for measuring flow rates in pipes. The
Venturi meter is basically a pipe segment consisting of an inlet section,
a converging section, a throat, and with a diverging outlet section as
illustrated in Figure 6-9. The water velocity is increased in the
constricted portion of the inlet section resulting in a decrease in the
static pressure. The pressure difference between the inlet pipe and the
throat is proportional to the square of the flow. The pressure difference
can easily be measured very accurately, resulting in an accurate flow
measurement. One of the advantages of the Venturi meter is that it
causes little pressure (head) loss.
The formula for calculating the flow in a Venturi meter is as follows:
Q = cKd2\hl - n2 (Kin9 1963)
where:
Q = volume of water, in cubic feet per second
c = discharge coefficient, obtain from Table 6-7. C varies with
Reynold's number, meter surfaces, and installation
hi = pressure head at center of pipe at inlet section, in feet of
water
h2 = pressure head at throat, in feet of water
K = constant which relates d2 to di for Venturi meters. Obtain
values of K from Table 6-8 or calculate according to the formula
NPDES Inspection Manual6-8January 1988
-------
Chapter Six Flow Measurement
K = J 2g (King, 1963)
where:
d2 = throat diameter, in feet
d]_ = diameter of inlet pipe, in feet
Electromagnetic Flowmeter. The electromagnetic flowmeter operates according
to Faraday s Law of Induction: the voltage induced by a conductor moving
at right angles through a magnetic field will be proportional to the velocity
of the conductor through the field. In the electromagnetic flowmeter,
the conductor is the liquid stream to be measured and the field is produced
by a set of electromagnetic coils. A typical electromagnetic flowmeter
is shown in Figure 6-10. The induced voltage is transmitted to a converter
for signal conditioning. The meter may be provided with recorder and
totalizer using electric or pneumatic transmission systems. This type of
flowmeter is useful at sewage lift stations and for measuring total raw
wastewater flow or raw or recirculated sludge flow.
Electromagnetic flowmeters are used in full pipes and have many advan-
^ages, including: accuracies of +1 percent, a wide flow measurement range,
a negligible pressure loss, no moving parts, and rapid response time.
However, they are expensive and buildup of grease deposits or pitting by
abrasive wastewaters can cause error. Regular checking and cleaning of
the electrodes is necessary. The meter electronics can be checked for
proper operation with devices especially made for this purpose. The
meter should be checked at least annually. The calibration of an
electromagnetic flow meter can not be verified except by returning it to
the factory or by the dye dilution method.
Propeller Meter. The propeller meter (Figure 6-11) operates on the
principle that liquid hitting the propeller will cause the propeller to
rotate at a speed proportional to the flow rate. The meter is self-
contained and requires no energy or equipment other than a mechanical
totalizer to obtain a cumulative flow reading. Equipment may be added to
the meter to produce a flow reading, to pace chemical feed equipment, and
to control telemetering equipment for remote readout. The calibration of
a propeller meter can be checked by returning it to the factory, by
comparing its readings to another meter measuring the same flow, or by
using the dye dilution method.
Secondary Devices
Secondary devices are the devices in the flow measurement system that
translate the interaction of primary devices in contact with the fluid
into the desired records or readout. They can be organized into two
broad classes:
NPDES Inspection Manual5^9January 1988
-------
Chapter Six Flow Measurement
• Nonrecording type with direct readout (e.g., a staff gauge)
or indirect readout from fixed points (e.g., a chain, wire
weight, float)
• Recording type with either digital or graphic recorders (e.g.,
float in well, float in flow, bubbler, electrical, acoustic).
The advantages and disadvantages of various secondary devices are provided
in Table 6-9.
Some wastewater facilities may need to measure flow by means of pumps in
which discharge-versus-power relationships have been determined from
measurements of the average output or input during a period in which dis-
charge measurements were made. Suitable curves may be developed from
these test data. When readily available from the manufacturer, pump
curves may be used by the inspector to estimate flow.
Due to wear on pumps and uncertainty regarding actual discharge heads,
pump curves at best only provide an estimate of the flow. Pump curves
are not normally accurate enough to be used for NPDES permit discharge
flow measurements. Pump curves have been used for determining large
flows, such as the cooling water discharge from large steam electric
power plants, where a high degree of accuracy was not necessary.
NPDES Inspection Manual 6-10 January 1988
-------
Table 6-1
Head-Discharge Relationship Formulas for Nonsubmerged Weirs*
n>
->
Weir Type
Contracted
Suppressed
Remarks
Reference
Rectangular
Franci s
formulas
= 3.33 (L - 0.1nH)Hl.5
Q = 3.33 L Hi-5
Approach velocity King
neglected 1963
Q = 3.33 [(H + h)l-5-hl.5](L - O.lnH) Q = 3.33 L[(H + h)1.5 - hl-5] Approach velocity King
considered 1963
Cipolletti Q = 3.367 L Hi.5
Q = 3.367 L (H + h)1.5 - hi.5
V-notch
Formula for 0 = 2.50 H2.5
90° V-notch
only
Q= 3.01 H2-48
NA
NA
NA
NA
Approach velocity King
neglected 1963
Approach velocity EPA
considered 1973
Not appreciably King
affected by 1963
approach velocity
Head measured at Eli and
weir plate Peterson 1979
EPA-61809A-2B
0 = discharge in cubic feet per second
H = head in feet
NA = not applicable
HW = head in feet at weir plate
n = number of end contractions
L = crest length in feet
h = head in feet due to the approach velocity = v2/2g
V = approach velocity
g = gravity (32.2 ft/sec2)
*Selection of a formula depends on its suitability and parameters under consideration.
-------
Chapter Six
Flow Measurement
TABLE 6-2
Head(3
Wei r
i n
Feet
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0.13
0.14
0.15
0.16
0.17
0.18
0.19
0.20
0.21
0.22
0.23
0.24
0.25
0.26
0.27
0.28
0.29
0.30
0.31
0.32
0.33
0.34
0.35
0.36
0.37
0.38
0.39
0.40
0.41
0.42
0.43
0.44
0.45
EQUATION Q=3.
cubic feet
DISCHARGE
FLOW
RATE
in
CFS
0.003
0.004
0.006
0.008
0.010
0.013
0.016
0.019
0.023
0.027
0.032
0.037
0.043
0.049
0.056
0.063
0.070
0.079
0.087
0.097
0.107
0.117
0.128
0.140
0.152
0.165
0.178
0.193
0.207
0.223
0.239
0.256
0.273
0.291
0.310
0.330
0.350
0.371
0.393
0.415
OF 90° V
HEAD(3
WEIR
i n
FEET
0.46
0.47
0.48
0.49
0.50
0.51
0.52
0.53
0.55
0.55
0.56
0.57
0.58
0.59
0.60
0.61
0.62
0.63
0.64
0.65
0.66
0.67
0.68
0.69
0.70
0.71
0.72
0.73
0.74
0.75
0.76
0.77
0.78
0.79
0.80
0.81
0.82
0.83
0.84
0.85
01 Hw2-48 where Hw i
per second
T"- ~~ r; T~
-NOTCH WEIR -
FLOW
RATE
in
CFS
0.439
0.463
0.488
0.513
0.540
0.567
0.595
0.623
0.653
0.683
0.715
0.747
0.780
0.813
0.848
0.883
0.920
0.957
0.995
1.034
1.074
1.115
1.157
1.199
1.243
1.287
1.333
1.379
1.426
1.475
1.524
1.574
1.625
1.678
1.730
1.785
1.840
1.896
1.953
2.012
s head is in
HEAD MEASURED AT
HEAD@
WEIR
in
FEET
0.86
0.87
0.88
0.89
0.90
0.91
0.92
0.93
0.94
0.95
0.96
0.97
0.98
0.00
1.00
1.01
1.02
1.03
1.04
1.05
1.06
1.07
1.08
1.09
1.10
1.11
1.12
1.13
1.14
1.15
1.16
1.17
1.18
1.19
1.20
1.21
1.22
1.23
1.24
1.25
feet at the weir
WEIR PLATE
FLOW
RATE
in
CFS
2.071
2.140
2.192
2.255
2.318
2.382
2.448
2.514
2.582
2.650
2.720
2.791
2.863
2.936
3.010
3.085
3.162
3.239
3.317
3.397
3.478
3.556
3.643
3.727
3.813
3.889
3.987
4.076
4.166
4.257
4.349
4.443
4.538
4.634
4.731
4.829
4.929
5.030
5.132
5.235
and Q is in
6-12
January 1988
-------
Chapter Six
Flow Measurement
Table 6-3
Minimum and Maximum Recommended Flow Rates
for Cipolletti Wei rs
Crest
Length,
ft.
1
1.5
2
2.5
3
4
5
6
8
10
Minimum
Head, ft.
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
Minimum
Flow Rate
MGD
0.195
0.292
0.389
0.487
0.584
0.778
0.973
1.17
1.56
1.95
CFS
0.301
0.452
0.602
0.753
0.903
1.20
1.51
1.81
2.41
3.01
Maximum
Head, ft.
0.5
0.75
1.0
1.25
1.5
2.0
2.5
3.0
4.0
5.0
Maximum
Flow Rate
MGD
0.769
2.12
4.35
7.60
12.0
24.6
43.0
67.8
139.0
243.0
CFS
1.19
3.28
6.73
11.8
18.6
38.1
66.5
105.0
214.0
375.0
Table 6-4
Minimum and Maximum Recommended Flow Rates
for Free Flow Through Parshall Flumes
Throat
Width,
W
1 in.
2 in.
3 in.
6 in.
9 in.
1 ft.
1-1/2 ft.
2 ft.
3 ft.
4 ft.
5 ft.
6 ft.
8 ft.
10 ft.
12 ft.
Minimum
Head, Ha
ft.
0.07
0.07
0.10
0.10
0.10
0.10
0.10
0.15
0.15
0.20
0.20
0.25
0.25
0.30
0.33
Minimum
Flow Rate
MGD
0.003
0.007
0.018
0.035
0.059
0.078
0.112
0.273
0.397
0.816
1.00
1.70
2.23
3.71
5.13
CFS
0.005
0.011
0.028
0.054
0.091
0.120
0.174
0.423
0.615
1.26
1.55
2.63
3.45
5.74
7.93
Maximum
Head, Ha
ft.
0.60
0.60
1.5
1.5
2.0
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
3.5
4.5
Maximum
Flow Rate
MGD
0.099
0.198
1.20
2.53
5.73
10.4
15.9
21.4
32.6
43.9
55.3
66.9
90.1
189
335
CFS
0.153
0.306
1.86
3.91
8.87
16.1
24.6
33.1
50.4
67.9
85.6
103
139
292
519
NPDES Inspection Manual
6-13
January 1988
-------
Chapter Six
Flow Measurement
Table 6-5
Free-Flow Values of C and N for Parshall Flume
Based on the Relationship Q = CWHfln
(American Petroleum Institute 1969)
Fl ume Throat, W
1
2
3
6
9
1
1.5
2
3
4
5
6
7
8
in
in
in
i n
in
ft
ft
ft
ft
ft
ft
ft
ft
ft
C
0.338
0.676
0.992
2.06
3.07
4 W *
11
"
11
"
11
"
"
n
1.55
1.55
1.55
1.58
1.53
1.522W0'026
11
"
11
11
"
"
11
Max. Q cfs
0.15
0.30
1.8
3.9
8.9
16.1
24.6
33.1
50.4
67.9
85.6
103.5
121.4
139.5
Where:
W = Flume throat width
Q = Flow (cfs)
C = Constant
H = Head upsteam of the flume throat (feet)
n = Constant
* = W should be represented in feet to calculate C
NPDES Inspection Manua
January 1988
-------
Chapter Six
Flow Measurement
Table 6-6
Minimum and Maximum Recommended Flow Rates for Free
Flow Through Plasti-Fab Palmer-Bowlus Flumes
D
Flume
Size,
(in.)
6
8
10
12
15
18
21
24
27
30
Maximum Slope
for
Upstream,
Percent
2.2
2.0
1.8
1.6
1.5
1.4
1.4
1.3
1.3
1.3
Minimum
Mead
(ft.)
0.11
0.15
0.18
0.22
0.27
0.33
0.38
0.44
0.49
0.55
Minimum
Flow Rate
MGD
0.023
0.048
0.079
0.128
0.216
0.355
0.504
0.721
0.945
1.26
CFS
0.035
0.074
0.122
0.198
0.334
0.549
0.780
1.12
1.46
1.95
Maximum
Head
(ft.)
0.36
0.49
0.61
0.73
0.91
1.09
1.28
1.46
1.64
1.82
Maximum
Flow Rate
MGD
0.203
0.433
0.752
1.18
2.06
3.24
4.81
6.70
8.95
11.6
CFS
0.315
0.670
1.16
1.83
3.18
5.01
7.44
10.4
13.8
18.0
NPDES Inspection Manual
6-15
January 1988
-------
Chapter Six
Flow Measurement
Table 6-7
Coefficients of Discharge c for Venturi Meters
(King 1963)
Diameter of
Throat, in.
1
2
4
8
12
18
48
Throat Velocity, ft. per sec
3
0.935
0.939
0.943
0.948
0.955
0.963
0.970
4
0.945
0.948
0.952
0.957
0.962
0.969
0.977
5
0.949
0.953
0.957
0.962
0.967
0.973
0.980
10
0.958
0.965
0.970
0.974
0.978
0.981
0.984
15
0.963
0.970
0.975
0.978
0.981
0.983
0.985
20
0.966
0.973
0.977
0.980
0.982
0.984
0.986
30
0.969
0.974
0.978
0.981
0.983
0.985
0.987
40
0.970
0.975
0.979
0.982
0.984
0.986
0.988
50
0.972
0.977
0.980
0.983
0.985
0.986
0.988
Table 6-8
Values of K in Formula for Venturi Meters
(King 1963)
-4
0.20
0.21
0.22
0.23
0.24
0.25
0.26
0.27
0.28
0.29
0.30
0.31
0.32
K
6.31
6.31
6.31
6.31
6.31
6.31
6.31
6.32
6.32
6.32
6.33
6.33
6.33
4
0.33
0.34
0.35
0.36
0.37
0.38
0.39
0.40
0.41
0.42
0.43
0.44
0.45
K
6.34
6.34
6.35
6.35
6.36
6.37
6.37
6.38
6.39
6.40
6.41
6.42
6.43
d2
~^
0.46
0.47
0.48
0.49
0.50
0.51
0.52
0.53
0.54
0.55
0.56
0.57
0.58
K
6.45
6.46
6.47
6.49
6.51
6.52
6.54
6.54
6.59
6.61
6.64
6.66
6.69
d2
~5*
0.59
0.60
0.61
0.62
0.63
0.64
0.65
0.66
0.67
0.68
0.69
0.70
0.71
K
6.72
6.75
6.79
6.82
6.86
6.91
6.95
7.00
7.05
7.11
7.17
7.23
7.30
d2
~d*
0.72
0.73
0.74
0.75
0.76
0.77
0.78
0.79
0.80
0.81
0.82
0.83
0.84
K
7.37
7.45
7.53
7.62
7.72
7.82
7.94
8.06
8.20
8.35
8.51
8.69
8.89
NPDES Inspection Manual
6-16
January 1988
-------
Chapter Six
Flow Measurement
Table 6-9
Advantages and Disadvantages of Secondary Devices
Device
Advantages
Disadvantages
Hook gauge
Stage board
Pressure measurement
a. Pressure bulb
b. Bubbler tube
Float
Dipper
Ultrasonic
Common
Common
Since no compressed air
is used, source can be
linked directly to
sampler
Self-cleaning, less
expensive, reliable
Inexpensive, reliable
Quite reliable, easy
to operate
No electrical or
mechanical contact
Requi re training to
use, easily damaged
Needs regular
cleaning, difficult to
read top of meniscus
Openings can clog,
expensive
Needs compressed air
or other air source
Catches debris,
requires frequent
cleaning to prevent
sticking and changing
bouyancy, and corroding
hinges
Oil and grease foul
probe causing possible
sensor loss
Errors from heavy
turbulence and foam,
calibration procedure
is more involved
than for other devices
NPDES Inspection Manual
TTT
January 1988
-------
Chapter Six
Flow Measurement
K = APPROX. O.l"
POINT TO
MEASURE
DEPTH, H
or
SHARP - CRESTED WEIR
WEIR CREST
MINIMUM
DISCHARGE LEVEL
FOR FREE FALL
FALL
WEIR
Figure 6-1
Profile and Nomenclature of Sharp-Crested Weirs
(Associated Water and Air Resource Engineers, Inc., 1973)
NPDES Inspection Manual
6-19
January 1988
-------
Crest Length
2Hmax L
Minimum Crest Length
»
' — — T^ — r"-; — •— """ ~ *•
., ^r~- . ',,i fT; '^ ^-.
. ,— •
1 — Hmax
. ••"•; •'T- ~ ~ '— • '."V-*'
- *—.. • -. , t..--^~*.*e
k_2Hmax
Minimum
<—)
IT
OJ
fD
-1
oo
X
Suppressed (Without End Contractions)
Rectangular Weir
Trapezoidal (Clpollettl) Sharp-Crested Weir
2Hmax L
Minimum Crest Length
;
1 4 ' •>
^.^^rrrJ^^ifj; ^2
i
i
-Hmax
2Hmax
~ Minimum
2Hmax
Minimum
o
s:
fD
DJ
trt
n>
ro
Contracted (With End Contractions)
Rectangular Weir Figure 6-2
V-Notch (Triangular) Sharp-Crested Weir
Three Common Types of Sharp-Crested Weirs
(Associated Water and Air Resource Engineers, Inc., 1973)
-------
Chapter Six
Flow Measurement
24 a
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Figure 6-3
Flow Rates for 60° and 90° V-Notch Weirs
(Associated Water and Resource Engineers, Inc., 1973)
-------
Chapter Six
1.0-
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rVb
Note: Based on Francis weir formulas
as follows: Where:
Q = 3.33 LH3/2 (for suppressed weir) Q = discharge, in cubic
or Q = 3.33 (L-0.2H)H3/2 - 0.66H5/2 feet per second
(for contracted weir with L = length of weir, in
two end contractions) feet
H = head, in feet
Figure 6-4
Nomograph for Capacity of Rectangular Weirs
(Associated Water and Air Resource Engineers, Inc. 1973)
NPDES Inspection Manual
6-22
January 1988
-------
Chapter Six
Flow Measurement
GPM
1,000,000
800,000
600,000
500,000
400,000
300,000
200,000
100,000
80,000
60,000
50,000
40,000
30,000
20,000
10,000
8000
6000
5000
4000
3000
2000
GPM
1000
800
600
500
400
300
200
100
80
60
SO
40
30
20
FLOW
10
8
MGO
_ 3000
2000
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MEAD -INCHES / I ~
"" i i i/iii. .1 i/i iii. iii
2 3/ 4 5 6 8 1.0 2 / 3 4 5 6 8 10
HEAD -FEET 1 1
CFS
4000
3000
2000
1000
800
600
500
400
300
200
100
80
60
50
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001
FIVC INCHCS IS NIIIMU* FULL SCM.!
MCAO KITH FOIUM FLOAT AM CAII.C
NCTCI
THIHTY JII IHCHCS IS MIIWM FULL
SCM.C HCAO KITH FOIMM) FLOAT MO
CA(LC HfTC*
Figure 6-5
Flow Curves for Parshall Flumes
(Associated Water and Air Resource Engineers, Inc. 1973)
January 1988
NPDES Inspection Manual
6-23
-------
l/l
3
O
<-»
O
3
Cu
C.
Cu
Ol
•3
C.
oo
oo
h—M
Water
Surface
B
-4—T
I
"Level Floor |
Submerged Flow
N
K
X-H
Zero Reference
^ Level for Ha
and *
Figure 6-6
Dimensions and Capacities of Parshall Measuring Flumes for Various Throat Widths
(Associated Water and Air Resource Engineers, Inc. 1973)
-------
W
A |A
B
C
D E
T
G
H K
H
N
P
R
X
Free-Flow
Capacity
y (Second-Foot*)
Mini-
Ft .
0
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0
1
1
2
3
4
5
6
7
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In.
3
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11
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1
10}
6
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4
6
8T
Ft. In.
0 0
1 4
1 8
1 8
1 8
2 0
2 0
2 0
2 0
2 0
In.
1
2
2
2
2
2
2
2
2
2
In. •
li 0
3 0
3 0
3 0
3 0
3 0
3 1
3 1
3 2
3 3
3 3
UB
.03
.05
.09
.11
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.42
.61
.3
.6
.6
.0
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Maxi-
•UM
1.9
3.9
8.9
16.1
24.6
33.1
50.4
67.9
85.6
103.5
121.4
139.5
•Equals 1 cu. ft. pel sec.
LBCHC:
W Width of flune throat.
A Length of side wall of converging section.
jA Distance back from end of crest to gage point.
B Axial length of converging section.
C Width of downstream end of flume.
D Width of upstream end of flume.
E Depth of flume.
T Length of flume throat.
G Axial length of diverging section.
H Length of side vail of the diverging section.
K Difference in elevation between lover end of Qune and crest.
N Length of approach floor.
N Depth of depression in throat below crest.
P Width between ends of curved wing walls.
R Radius of curved wing wall.
X Horizontal distance to 1^ gage point from low point in throat.
Y Vertical distance to h^ gage point from low point in throat.
Figure 6-6
Dimensions and Capacities of Parshall Measuring Flumes for Various Throat Widths (Continued)
-------
Chapter Six
Flow Measurement
100
w» Width of flume
100
SUBMERGENCE, ^ , IN PERCENT
HQ
Figure 6-7
Effect of Submergence on Parshall Flume Free Discharge
(Civil Engineering, ASCE)
NPDES Inspection Manual
6-26
January 1988
-------
Chapter Six
Flow Measurement
Upper
Transition
Lower
Transition
Flow
Upstream
Depth
Water Surface
i
n
H
r»-
, £ „
1
"^^^
^^^
Throat
Preferred Head
Measuring Point
D = Conduit Diameter
Figure 6-8
Free Flowing Palmer-Bowl us Flume
Small Jump
•Should Occur
In This Region
Downstream
Depth
THROAT
INLET SECTION SECTIO
OUTLET SECTION
PIPE OIA
HIGH
PRESSUR!
TAP
THROAT OIA.
Figure 6-9
Configuration and Nomenclature of Venturi Meter
NPDES Inspection Manual
"6^27
January 1988
-------
Chapter Six
Flow Measurement
INSULATING
LINER
ELECTRODE
ASSEMBLY
MAGNET COILS
[
POTTING COMPOUND
STEEL METER
BODY
Figure 6-10
Electromagnetic Flowmeter
FLOW
REDUCTION
GEARS
STRAIGHTENING
VANES
DIRECT READING
TOTALIZER
EVEL GEARS
PROPELLER
Figure 6-11
Propeller Flowmeter
NPDES Inspection Manua'
6-28
January 1988
-------
Chapter Six
C FLOW MEASUREMENT COMPLIANCE
Objectives
The current compliance strategy depends heavily on the permittee's submittal
of self-monitoring data. The flow discharge measured during the NPDES
compliance inspection should verify the flow measurement data collected
by the permittee, support any enforcement action that may be necessary,
and provide, eventually, a basis for reissuing or revising the NPDES permit.
Flow Measurement System Evaluation
The responsibility of the inspector during NPDES compliance flow measure-
ment inspection includes collecting accurate flow data during the inspec-
tion and validating data collected during the permittee's self-monitoring.
The NPDES inspector must check both the permittee's flow data and the flow
measurement system to verify the permittee's compliance with NPDES permit
requirements. When evaluating a flow measurement system, the inspector
should consider and record findings on:
• Whether the system measures the entire discharge flow.
• The system's accuracy and good working order. This will include
a thorough physical inspection of the system and comparison of
system readings to those obtained with calibrated portable
instruments.
• The need for new system equipment.
• The existence or absence of a routine calibration and maintenance
program for flow measurement equipment.
If the permittee's flow measurement system is accurate within +10 percent,
the inspector is encouraged to use the installed system. If the flow
NPDES Inspection Manual 6-29 January 1988
-------
Chapter Six Flow Measurement
sensor or recorder is found to be inaccurate, the inspector should
determine whether the equipment can be corrected in time for use during
the inspection. If the equipment cannot be repaired in a timely manner,
the portable flow sensor and recorder used to assess the accuracy of the
permittee's system should be used for the duration of the inspection. If
nonstandard primary flow devices are being used, the permittee should
supply data on the accuracy and precision of the method being employed.
For flow measurement in pipelines, the inspector may use a portable
flowmeter. The inspector should select a flowmeter with an operating
range wide enough to cover the anticipated flow to be measured. The
selected flowmeter should be tested and calibrated before use. The
inspector should select the site for flow measurement according to permit
requirements and install the selected flowmeter per the manufacturer's
specifications. The inspector should use the proper tables, charts, and
formulas as specified by the manufacturer to calculate flow rates.
Four basic steps are involved in evaluating the permittee's flow measure-
ment system:
• Physical inspection of the primary device
• Physical inspection of the secondary device and ancillary
equi pment
• Flow measurement using the primary/secondary device combination
of the permittee
0 Certification of the system using a calibrated, portable instrument.
In the following sections, procedures are presented for inspecting the
more common types of primary and secondary devices, for measuring flow
using common permanent and portable systems, and for evaluating flow
data. It must be emphasized that the number of primary/secondary device
permutations is limitless. Therefore, it is not feasible to provide
procedures for all systems. When systems other than those discussed
here are encountered, the inspector is strongly encouraged to consult the
manufacturers for advice before preparing a written inspection procedure.
Primary Device Inspection Procedures
The two most common open channel primary devices are sharp-crested weirs
and Parshall flumes. Common sources of error when using them include:
• Faulty fabrication--weirs may be too narrow or not "sharp"
enough. Flume surfaces may be rough or critical dimensions may
exceed tolerances or throat walls may not be vertical.
• Improper installation--weirs and flumes may be installed too
near pipe elbows, valves, or other sources of turbulence. The
devices may be out of level or plumb.
• Sizing errors—the primary device's recommended applications
may not include the actual flow range.
NPDES Inspection Manual6-30January 1988
-------
Chapter Six Flow Measurement
• Poor maintenance—primary devices corrode and deteriorate.
Debris and solids may accumulate in them.
Specific inspection procedures for the sharp crested weir, the Parshall
flume, and the Pa-lmer-Bowlus flume devices follow.
Sharp-Crested Weir Inspection Procedures
t Inspect the upstream approach to the weir
- Verify that the weir is perpendicular to the flow direction.
- Verify that the approach is a straight section of conduit
with a length at least 20 times the maximum expected head of
liquid above the weir crest.
- Observe the flow pattern in the approach channel. The flow
should occur in smooth stream lines without velocity gradients
and turbulence.
- Check the approach, particularly in the vicinity of the weir,
for accumulated solids, debris, or oil and grease. The
approach must have no accumulated matter.
t Inspect the weir
- Verify that the crest of the weir is level across the entire
conduit traverse.
- Measure the width of the weir crest. The edge of the weir crest
should be no more than 1/8-inch thick.
- Make certain the weir crest corresponds to zero gauge elevation
(zero output on the secondary device).
- Measure the angle formed by the top of the crest and the upstream
face of the weir. This angle must be 90 degrees.
- Measure the chamfer on the downstream side of the crest. The
chamfer should be approximately 45 degrees.
- Visually survey the weir-bulkhead connection for evidence of
leaks or cracks which permit by-pass.
- Measure the height of the weir crests above the channel floor.
The height should be at least twice the maximum expected head
of liquid above the crest.
- Inspect the weir for evidence of corrosion, scale formation, or
clinging matter. The weir must be clean and smooth.
- Observe flow patterns on the downstream side of the weir.
Check for the existence of an air gap (ventilation) immediately
adjacent to the downstream face of the weir. Ventilation is
necessary to prevent a vacuum that can induce errors in head
measurements. Also ensure that the crest is higher than the
maximum downstream level of water in the conduit.
- Verify that the nappe is not submerged and that it springs free
of the weir plate.
- If the weir contains a V-notch, measure the apex angle. The
apex should range from 22.5 degrees to 90 degrees. Verify that
the head is between 0.2 and 2.0 feet. The weir should not be
operated with a head of less than 0.2 feet since the nappe may
not spring clear of the crest.
NPDES Inspection Manual 57H January 1988
-------
Chapter Six Flow Measurement
King's Handbook of Hydraulics, 1963, frequently referenced throughout
this chapter provides a detailed discussion on weirs.
Parshall Flume Inspection Procedures
• Inspect the flume approach
- The flow pattern should be smooth with straight stream lines,
be free of turbulence, and have a uniform velocity across the
channel.
- The upstream channel should be free of accumulated matter.
• Inspect the flume
- The flume should be located in a straight section of the
conduit.
- Flow at the entrance should be free of "white" water.
- The flume should be level in the transverse and translational
di rections.
- Measure the dimensions of the flume. Dimensions are strictly
prescribed as a function of throat width (see Figure 6-5 for
critical dimensions).
- Measure the head of liquid in the flume and compare with the
acceptable ranges in Table 6-4.
• Inspect the flume discharge
- Verify that the head of water in the discharge is not restricting
flow through the flume. The existence of a "standing wave" is
good evidence of free flow and verifies that there is no sub-
mergence present.
- Verify whether submergence occurs at or near maximum flow.
Palmer-Bowlus Flume Inspection Procedures
• Inspect the flume approach as outlined above (these flumes are
seldom used for effluent flow measurement).
• Inspect the flume
- The flume should be located in a straight section of the
conduit.
- Flow at the entrance should be free of "white water."
- Observe the flow in the flume. The profile should approximate
that depicted in Figure 6-8.
- The flume should be level in the transverse direction and
should not exceed the translational slope in Table 6-6.
- Measure the head of water in the flume. Head should be
within the ranges specified in Table 6-6.
NPDES Inspection Manual 57TZ January 1588
-------
Chapter Six Flow Measurement
• Inspect the flume discharge
- Verify that free flow exists. Look for the characteristic
"standing wave" in the divergent section of the flume.
Venturi Meter Inspection Procedures
t Verify that Venturi meter is installed according to manufacturer's
instructions.
• Verify that Venturi meter is installed downstream from a straight
and uniform section of pipe, at least 5 to 20 diameters, depending
on the ratio of pipe to throat diameter and whether straightening
vanes are installed upstream. (Installation of straightening
vanes upstream will reduce the upstream piping requirements.)
• Verify that the pressure measuring taps are not plugged.
• Calibrate Venturi meter in place by either volumetric method or
comparative dye dilution method to check the manufacturer's
calibration curve or to develop a new calibration curve.
Secondary Device Inspection Procedures
Common sources of error in the use of secondary devices are:
• Improper location—gauge is located in the wrong position
relative to the primary device
• Inadequate maintenance—gauge is not serviced regularly
• Incorrect zero setting—zero setting of gauge is not the
zero point of the primary device
• Operator error-human error in reading.
Specific inspection procedures follow.
Flow Measurement in Weir Applications
• Determine that the head measurement device is positioned 3 to 4 head
lengths upstream of a weir
t Verify that the zero or other point of the gauge is equal to that
of the primary device.
The inspector should use an independent method of measuring head, such as
with a yardstick or carpenter's rule (be sure to measure at least 4 Hmax
upstream and convert to nearest hundredth of a foot). To determine flow rate
use the appropriate head discharge relationship formula (see Table 6-1).
NPDES Inspection Manual 6-313 January 1988
-------
Chapter Six Flow Measurement
Flow Measurement in Parshall Flume Applications
Flow Measurement—Free-Flow Conditions.
• Determine upstream head (Ha) using staff gauge
- Verify staff gauge is set to zero head. A yardstick or
carpenter's rule can be used.
- Verify staff gauge is at proper location (two-thirds the
length of the converging section back from the beginning
of the throat)
- Read to nearest division the gauge division at which
liquid surface intersects gauge
- Read Ha in feet from staff gauge.
0 To determine flow rate, use Figure 6-6 in the unit desired, or
use tables published in flow measurement standard references, or
calculate using the coefficients in Table 6-5.
Flow Measurement--Submerged-Flow Condition.
Generally, it is difficult to make field measurements with submerged-flow
conditions. In cases when measurements can be obtained (using a staff
or float-gauge), the procedures listed below should be followed:
0 Determine upstream head using staff or float gauge
- Read to nearest division and, at the same time as for H(j,
the gauge division at which liquid surface intersects gauge
- Calculate Ha from gauge reading
0 Determine downstream head (H^) using staff or float gauge
- Hb refers to a measurement at the crest
- Read to nearest division, and at the same time as for Ha,
the gauge division at which liquid surface intersects gauge
- Calculate Hb from staff reading
0 Determine flow rate
Hb
- Calculate percent submergence
Ha
X 100
- Consult Table 6-6
- When a correction factor is obtained, use Ha and find free-
flow from Figure 6-6
- Multiply this free-flow value by the correction factor to
obtain the submerged flow.
The inspector may use an independent method of measuring head, such as
a yardstick or carpenter's rule at the proper head measurement
NPDES Inspection Manual 6-34 January 1988
-------
Chapter Six Flow Measurement
point. Due to the sloping water surface in the converging section of a
flume, it is essential that the proper head measurement point be used.
Flow Measurement in Palmer-Bowlus Flume Applications
• Obtain head measurements as in the Parshall Flume application,
using the secondary device. The head is the height of water
above the step. The total depth upstream of the step is not the
head.
• Refer to manufacturer-supplied discharge tables to convert head
measurements to flow data. Palmer-Bowlus flumes, unlike Parshall
flumes, are not constructed to rigid dimensional standards. The
inspector must not use discharge tables supplied by other
manufacturers.
Verification
Most flow measurement errors result from inadequate calibration of the
flow, totalizer and recorder. If the inspector has determined that
the primary device has been installed properly, verification of the
permittee's system is relatively simple. The flow determined from the
inspector's independent measurement is compared to the flow of the
permittee's totalizer or recorder. The inspector's flow measurements
should be within 10 percent of the permittee's measurements to certify
accurate flow measurement. Optimally, flow comparisons should be made
at various flow rates to check system accuracy.
When the permit requires that the daily average flow be measured by a
totalizing meter, the inspector should verify that the totalizer is
accurate, i.e., properly calibrated. This can be done during a period of
steady flow by reading the totalizer and at the same time starting a stop
watch. The stop watch should be started just as a new digit starts to
appear on the totalizer. After ten to thirty minutes, the totalizer
should be read again, just as a new digit begins to appear, the stop
watch is read. By subtraction of the two totalizer readings, the total
flow over the measured time period can be obtained. The flow rate in
gallons per minute can be calculated by using the time from the stop watch,
This flow rate should be compared to the flow determined by actual
measurement of the head made at the primary device at the time interval.
The calibration of the totalizer should be considered satisfactory if the
two flows are within ten percent of each other, when the actual measured
flow is used as the known value, or divisor, in the percent calculation.
NPDES Inspection Manual 6-35 January 1988
-------
Chapter Six
D REFERENCES AND FLOW
MEASUREMENT INSPECTION
CHECKLIST
References
American Petroleum Institute. 1969. Manual on Disposal of Refinery
Wastes. Chapter 4.
Associated Water and Air Resource Engineers, Inc. 1973. Handbook for
Industrial Hastewater Monitoring, U.S. EPA, Technology Transfer.
Blasso, L. 1975. "Flow Measurement Under Any Conditions," Instruments
and Control Systems, 48(2): 45-50.
Bos, M.G. 1976. Discharge Measurement Structures. Working Group on
Small Hydraulic Structures International Institute for Land Reclamation
and Improvement, Wageningen, The Netherlands.
Eli, R. and H. Pedersen, 1979. Calibration of a 90° V-Notch Weir Using
Parameters Other than Upstream Head. EPA-61809A-2B
ISCO. 1985. Open Channel Flow Measurement Handbook. Lincoln, Nebraska.
(Contains tables of various flow measurement devices.)
King, H.W., and Brater, E.F. 1963. Handbook of Hydraulics, 5th ed. New York:
McGraw-Hill Book Co. (Contains tables of various flow measurement devices.)
Mauis, F.T. 1949. "How to Calculate Flow Over Submerged Thin-Plate
Weirs." Eng. News-Record, p. 65.
Metcalf & Eddy, Inc. 1972. Wastewater Engineering, New York: McGraw-Hill
Book Co.
Robinson, A.R. 1965. Simplified Flow Corrections for Parshall Flumes
Under Submerged Conditions. Civil Engineering, ASCE.
Shelley, P.E., and G.A. Kirkpatrick. 1975. Sewer Flow Measurement; A
State of the Art Assessment. U.S. EPA, EPA-600/2-75-027.
Simon, A. 1976. Practical Hydraulics, New York: John Wiley & Sons.
NPDES Inspection Manual6-37January 1988
-------
Chapter Six Flow Measurement
Smoot, G.F. 1974. A Review of Velocity-Measuring Devices. U.S. Department
of the Interior (USDI), U.S.G.S.Open File Report, Reston, Virginia.
Stevens. Water Resources Data Book. Beaverton, Oregon. (Contains
tables of various flow measurement devices.)
Thorsen, T., and R. Oden. 1975. "How to Measure Industrial Wastewater
Flow," Chemical Engineering, 82(4): 95-100.
U. S. Department of Commerce, National Bureau of Standards. 1975.
A Guide to Methods and Standards for the Measurement of Water Flow.
U. S. Department of the Interior (USDI), Bureau of Reclamation. 1967.
Water Measurement Manual, 2nd Ed. (Contains tables of various flow
measurement devices.)
NPDES Inspection Manual6TJBJanuary
-------
Chapter Six
Flow Measurement
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
FLOW MEASUREMENT INSPECTION CHECKLIST
A. GENERAL
1. a. Primary flow measuring device properly
installed and maintained.
b. Flow measured at each outfall? Number of
outfal Is?
c. Is there a straight length of pipe or channel
before and after the flowmeter of at least 5 to
20 diameters?
d. If a magnetic flowmeter is used, are there sources
of electric noise in the near vicinity?
e. Is the magnetic flowmeter properly grounded?
f. Is the full pipe requirement met?
2. a. Flow records properly kept.
b. All charts maintained in a file.
c. All calibration data entered into a log book.
3. Actual discharged flow measured.
4. Effluent flow measured after all return lines.
5. Secondary instruments (totalizers, recorders, etc.)
properly operated and maintained.
6. Spare parts stocked.
7. Effluent loadings calculated using effluent flow.
B. FLUMES
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
1.
2.
3.
4.
5.
6.
7.
a.
9.
10.
Flow entering flume reasonably well-distributed
across the channel and free of turbulence, boils, or
other disturbances.
Cross-sectional velocities at entrance relatively
uniform.
Flume clean and free of debris or deposits.
All dimensions of flume accurate and level.
Side walls of flume vertical and smooth.
Sides of flume throat vertical and parallel.
Flume head being measured at proper location.
Measurement of flume head zeroed to flume crest.
Flume properly sized to measure range of existing
flow.
Flume operating under free-flow conditions over
existing range of flows.
NPDES Inspection Manual
6-39
January 1988
-------
Flow Measurement
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
11
12
1.
2.
3.
4.
5.
6.
7.
8.
9.
10
11
12
1.
2.
J.
1.
2.
J.
4.
b.
b.
FLOW MEASUREMENT INSPECTION CHECKLIST
(Continued)
B. FLUMES (Continued)
. Flume submerged under certain flow conditions.
. Flume operation invariably free-flow.
C. WEIRS
What type of weir is being used?
Weir exactly level .
Weir plate plumb and its top and edges sharp and clean
Downstream edge of weir is champered at 45°.
Free access for air below the nappe of the weir.
Upstream channel of weir straight for at least
four times the depth of water level and free from
disturbances.
Distance from sides of weir to side of channel at
least 2H.
Area of approach channel at least (8 x nappe area)
for upstream distance of 15H.
If not, is velocity of approach too high?
. Head measurements properly made by facility
personnel .
. Leakage does not occur around weir.
. Proper flow tables used by facility personnel.
D. OTHER FLOW DEVICES
Type of flowmeter used:
What are the most common problems that the operator
has had with the flowmeter?
Measured wastewater flow: mgd;
Recorded flow: mgd; Error %
E. CALIBRATION AND MAINTENANCE
Flow totalizer properly calibrated.
Frequency of routine inspection by proper operator:
/day.
Frequency of maintenance inspections by plant
personnel : /year.
Flow meter calibration records kept.
Frequency of flow meter calibration: /month.
Flow measurement equipment adequate to handle expected
ranges of flow rates .
Calibration Frequency Adequate
-------
Chapter Seven
BIOMONITORING
Contents Page
A Evaluation of Permittee Self-Blomonitoring Program
Introduction 7-1
Objectives and Requirements 7-2
Effluent Sampling 7-2
Test Procedures 7-3
Test Results 7-4
Recordkeeping and Data Reporting 7-4
B Compliance Biomonitoring Inspection
Objectives and Requirements 7-9
Conducting Toxicity Tests 7-9
Effluent Sampling and Holding 7-10
Test Organisms 7-12
Facility and Equipment 7-13
Test Procedures 7-15
Reference Toxicants 7-17
Chain-of-Custody and Preservation of Documents 7-17
Data Reporting 7-18
Definitions 7-19
References 7-21
List of Tables
7-1 Recommended Species, Test Temperatures, and Life Stages ... 7-5
List of Figures
7-1 NPDES Toxicity Test Evaluation Form 7-7
NPDES Inspection Manual 7-i January 1988
-------
Chapter Seven
A EVALUATION OF PERMITTEE
SELF-BIOMONITORING PROGRAM
Introduction
This chapter highlights acute and chronic toxicity testing procedures
that may be required by a National Pollutant Discharge Elimination System
(NPDES) permit. The following section summarizes factors that the
inspector should evaluate during the inspection. Then another section
lists technical procedures that should be followed by the inspector and/or
permittee to conduct effluent toxicity tests. Toxicity tests are one
type of biomonitoring. They measure the degree of response produced by
exposure to a specific level of stimulus or concentration of chemical(s).
The inspector can use this information to guide his or her review of a
permittee's self-biomonitoring program or to plan toxicity tests.
Detailed procedures for biomonitoring testing are given in the EPA's
Methods for Measuring the Acute Toxicity of Effluents to Freshwater and
Marine Organisms (EPA 600/4-85/013) and in EPA's Methods for EstimatTng
the Chronic ToxTcity of Effluents and Receiving Haters to Freshwater
Organisms (EPA 600/4-85/014).Periodically, these procedures will be
updated and modified. Refer to the latest revision for specific procedures,
A biomonitoring inspection should include one or more of these objectives:
• Assess compliance with the discharger's NPDES permit limitations
and requirements
• Determine whether the records and reports required by the
discharger's NPDES permit are being maintained
Check the adequacy of the permittee's reports
Determine whether representative samples are being collected and
analyzed properly
Determine whether toxicity tests have been conducted properly
Determine need for toxicity limits
Evaluate the permittee's self-biomonitoring program.
NPDES Inspection Manual7^1January 1988
-------
Chapter Seven Biomonltorlng
Objectives and Requirements
The evaluation of a permittee's biomonitoring program includes a compliance
evaluation inspection (CEI) and performance audit inspection (PAI). During
a PAI, the inspector must review the performance of permittee staff and
evaluate their testing and sampling procedures. A CEI consists of an
examination of the permittee's biomonitori ng files and records, the
toxicity testing laboratory, and sampling records.
For each set of definitive acute toxicity test data, the 24-, 48-, or 96-
hour LC50 or EC50 and its 95 percent confidence limits must be calculated
on the basis of the initial volume percentage of effluent in the test
solutions.
For each set of chronic toxicity data, the no-observed-effect level (NOEL)
and confidence limits, as well as statistical comparisons where appropriate,
must be calculated to distinguish between control and experimental rates
of growth, reproduction, teratogenesis, or other long-term effects.
The inspector should understand a permittee's biomonitoring requirements
as stated in the permit and should determine whether or not a permittee's
biomonitoring program meets the requirements of the permit. The CEI and
PAI procedures for evaluating a permittee's self-biomonitoring program
address the following specific objectives:
• Assess compliance with the NPDES permit limitations and require-
ments (CEI)
• Determine adequacy of required reports and records (CEI)
• Determine adequacy of laboratory facility and equipment (CEI)
• Determine adequacy of effluent sampling and toxicity testing
procedures (PAI).
The inspector should observe and review the permittee's laboratory proce-
dures, equipment, facilities, and logs, or those of its contractors.
Sampling, facilities, test organisms, procedures, and records require
detailed on-site review and evaluation.
Effluent Sampling
Permittees should collect samples of the type and locations specified in
their permit. The test protocols should specify how the sample is obtained
and treated. The test should be initiated within 36 hours of collection
to avoid changes in potency. When evaluating a permittee's sampling
program, the inspector should verify that these requirements are fulfilled.
Facilities and Equipment. Effluent toxicity testing may be performed in
either a stationary or mobile laboratory. Toxicity testing facilities
may include equipment for rearing, holding, and acclimating test organisms.
These facilities should be well ventilated and free of fumes. Air supplies
NPDES Inspection Manual 7-2 January 1988
-------
Chapter Seven Biomonltoring
should be free of oil. Dilution water and temperature controls should be
high quality. Separated test areas should be provided. If marine organisms
are tested, the lab needs a source of saltwater and noncorroding containers.
Water temperature should be controlled by the use of circulating water
baths, heat exchangers, or environmental chambers during acclimation and
testing.
Test Organisms. Table 7-1 identifies species that have been used widely
in toxicity tests and are acceptable test organisms. The condition, age,
exposure history, and rearing or holding conditions can affect the results.
In general, wild stock are unacceptable unless these factors are known.
The inspector should look for discrepancies in the lab data or appearance
of the test organisms. For example, test organisms should have a survival
rate of at least 80 percent for invertebrates or 90 percent for vertebrates
during holding/acclimation (usually 7-14 days before the test). Poor
survival during holding periods suggests poor test conditions or poor
test organisms. In addition to survival, changes in fecundity and growth
can be used to evaluate the health of test organisms and maintenance of
the cultures.
Dilution Water. To determine inherent toxicity of a wastewater, a standard
reconstituted water normally is used. If the objective of the test is to
determine the effect of mixed receiving water and wastewater on the
organism, then receiving water or reconstituted water similar in chemical
characteristics (particularly for pH and hardness) to the receiving water
should be used. If the receiving water has toxic effects on the test
organisms, it is unsuitable as dilution water. Another nontoxic source
such as a nearby tributary, ground water, or synthetic water must be used
and noted. Dilution water from receiving water should be collected as
close to the outfall as possible, but it should be collected upstream
from or outside the influence of the effluent. Dilution water should be
obtained from the receiving water within 96 hours of the test. The
inspector should determine whether the source and use of dilution water
are adequate in terms of quality and timeliness.
Test Procedures
The most important aspect of the biomonitoring inspection is the observation
of permittee or contractor toxicity testing procedures and related labora-
tory analysis. The inspector should verify that conditions and procedures
are correct regarding:
Control and effluent dilution preparation
Procedures for transferring, allocating, and feeding test organisms
Recording of times for test setup and initiation
Temperature and dissolved oxygen (DO) ranges during the test
Test organism age, weight, length, and species.
NPDES Inspection Manual 7-3 January 1988
-------
Chapter Seven Blomonlton'ng
Test Results
The inspector should review test results in the permittee's records. The
test reports should include sufficient data to assure that the test results
were valid and reflect accurate estimates of effluent toxicity. Test
results should provide an estimate of the toxicity, a 95 percent confidence
interval, physical/chemical measurements, and observations during the
test. The inspector may use Figure 7-1 to evaluate test results or use
the questions appearing there as a guide to evaluate test procedures.
For details see Section 13 of EPA/600/4-85/013 and Section 10 of EPA/600/4-
85/014.
Recordkeeping and Data Reporting
Proper recordkeeping is essential to an effective program. Bound note-
books should be used to maintain detailed records of holding, acclimation,
rearing, and other information on equipment calibration, test conditions,
and end results. Annotations should be made as soon as possible to
prevent the loss of information. Figure 7-1 is a sample form to evaluate
effluent toxicity test results and test procedures. When evaluating the
permittee's data reporting, the inspector should verify that the following
are included:
t Summary of test results, description of test conditions, material
tested, and other data for quality assurance (see Figure 7-1)
• Methods used for al 1 chemical analyses
• Average and range of acclimation temperature and test temperature
• Any deviation from standard test methods
• Any other relevant information.
NPDES Inspection Manual7^4'January 1988
-------
Chapter Seven
Biomonitoring
Table 7-1
Recommended Species, Test Temperatures, and Life Stages
Species
Test
Temperature
(°C)a
Life
Stages6
Freshwater
Vertebrates
Cold Water
Brook trout
Coho salmon
Rainbow trout
Warm Water
Bluegil1
Channel catfish
Fathead minnow
Invertebrates
Cold Water
Stone flies
Crayfish
Mayflies
Warm Water
Amphipods
Cladocera
Crayfish
Mayflies
Midges
Salvelinus fontinalis 12 30-90 days
Oncorhynchus kisutch 12 30-90 days
Sal mo gairdnerii 12 30-90 days
Lepomis machrochirus
Ictalurus punctatus
Pimephales promefa?
20 1-90 days
20 1-90 days
20(26)c 1-90 days
Pteronarcys spp. 12 Larvae
Pacifastacus leniusculus 12 Juveniles
Baetis spp., Ephemerella spp. 12 Nymphs
Hya1e11 a spp., Gamma rus 20 Juveniles
lacustris, GL_ fasciatus,
G^ pseudolimnaeus
Daphnia magna, D. pulex.01 20(26)c 1-24 h
Ceriodaphnia dubTa
Orconectes spp., Cambarus spp., 20 Juveniles
Procambarus spp.
Hexagenia limbata, 20 Nymphs
H± bilineata
Chironomus spp. 20 Larvae
Source: U.S. Environmental Protection Agency. 1985. Methods for
Measuring the Acute Toxicity of Effluents to Freshwater and Marine
Organisms. 3rd ed. EPA 600/4-85/013.
aTo avoid unnecessary logistical problems in trying to maintain different
test temperatures for each test organism, it is sufficient to use one
temperature (12°C) for cold water organisms and one temperature (20°C) for
warm water organisms. See Note (c) for exceptions.
bThe optimum life stage is not known for all test organisms.
cShort-term subchronic test procedures (EPA 600/4-85/014, revised edition)
require 26°C with a minimum of 25°C.
When specific temperatures are cited in a protocol, they should be used.
dpaphnia pulex is recommended over D. magna because it is more widely dis-
tributed in the United States, test results are less sensitive to feeding
during tests, and it is not as easily trapped on the surface film.
NPDES Inspection Manual
7-5
January 1988
-------
Chapter Seven
Biomonitoring
Table 7-1
Recommended Species, Test Temperatures, and Life Stages (Continued)
Species
Marine and estuarine
Vertebrates
Cold Water
Engli sh sole
Sand dab
Winter flounder
Warm Water
Fl ounder
Longnose
killifish
Mummichog
Pinf ish
Sheepshead
minnow
Sil versides
Spot
Three-spined
stickleback
Invertebrates
Cold Water
Oungeness crab
Oceanic shrimp
Green sea urchin
Purple sea
urchin
Sand dollar
Warm Water
Blue crab
Mysid
Grass shrimp
Peneid shrimp
Sand shrimp
Paci fie oyster
American oyster
Test
Temperature Life
(°C) Stage
Parophrys vetulus
Citharichthys stigmaeus
Pseudopleuronectes americanus
Paralichthys dentatus,
P. lethostijjma
Fundulus similis
Fundulus heteroclitus
Lajjodon rhomboides
Cyprinodon variegatus
Menidia spp.
Leiostomus xanthurus
Gasterosteus aculeatus
Cancer magister
Pandalus jordani
Strongylocentrotus
drobachiensis
S. purpuratus
Dendraster excentricus
Callinectes sapidus
Mysidopsis spp., Neomysis spp.
Palaemonetes spp.
Peneus setiferus, P.
duorarum, P. axtecus
Crangon spp.
Crassostrea gi^as
Crassostrea virginica
12
12
12
20
20
20
20
20
20
20
20
12
12
12
12
12
20
20
20
20
20
20
20
1-90 days
1-90 days
Post-meta-
morphosis
1-90 days
1-90 days
1-90 days
1-90 days
1-90 days
1-90 days
1-90 days
1-90 days
Juveni le
Juvenile
Gametes/embryo
Gametes/embryo
Gametes/embryo
Juvenile
1-5 days
1-10 days
Post larval
Post larval
Post larval
Embryo/larval
NPOES Inspection Manual
7-6
January 1988
-------
Chapter Seven
Biomom'toring
Facility Name:
Facility Location:
Permit No.:
Laboratory Name:
Investigator's
Name:
Toxicity Test
Acute Toxicity Test: 24-Hour Static 48-Hour Static Daily Renewal
96-Hour Flow-through 96-Hour Static
Chronic Toxicity Test: 4-Day Static 7-Day Static Renewal
8-Day Static Renewal Other (Specify!
Renewal Frequency (specify test days)
Test Starting Date:
Test Temperature: _
Test Organism:
Name:
Completion Date:
Age (Hours or Days)
Summary of Results
Acute Toxicity Test:
Stress Observed
(Yes or No)
Mortality Observed
(Yes or No)
LC50
(% effluent)
Other
(Specify)
Chronic Toxicity Test:
Characteristic
NOEL
LOEL
Control/ %
Effluent
Survival
Growth
Reproduction
(Young/Female)
Hatch
Tetrogenesis
Figure 7-1
NPDES Toxicity Test Evaluation Form
NPDES Inspection Manual
January 1988
-------
Chapter Seven Biomonitoring
Quality Assurance Summary Acceptable Unacceptable
Is temperature maintained during tests within
+_2°C of the test temperature except for
Ceriodaphnia, for which the temperature is
kept + 1°C of the specified level? Yes No
Are DO levels always greater than 40% satura-
tion for warm water species and 60% saturation
for cold water species? Yes No
At a minimum, is a summary of responses for
each test concentration and control maintained? Yes No
Is the loading factor for all exposure chambers
less than or equal to the maximum allowed for the
test type and test temperature? Yes No
Does the water chemistry vary during the test? Yes No
If contaminant-free water is required, do
healthy test organisms survive in the dilution
water without signs of stress and does mortal-
ity not exceed 10% during the acclimation
period? Yes No
Is the control survival 90% or greater for
acute tests and 80% or greater overall for
chronic tests? Yes No
If tests are replicated, with a dilution
factor of 0.5, does the point estimate of
NOEL, assuming it falls within the range of
the LOEC, have a coefficient of variation
of +10%? Yes No
Are reference toxicant tests used and are the
results in the acceptable range? Yes No
Effluent Tested
Sampling Location(s): Type of Sample:
Sample Collection Dates/Times: ~
Dilution Water
Source Collection Date(s)
Figure 7-1
NPDES Toxicity Test Evaluation Form (Continued)
NPDES Inspection Manual7-8January 1988
-------
Chapter Seven
B COMPLIANCE BIOMONITORING
INSPECTION
Objectives and Requirements
The objectives of a compliance biomonitoring inspection are to:
t Screen for toxic conditions not yet detected in an effluent
• Evaluate compliance with water quality standards
t Monitor toxic compounds that may or may not be controlled through
economically achievable best control technology/best available
technology (BCT/BAT) practices
• Evaluate permit limitations
• Develop enforcement cases
• Investigate probable cause violations
• Develop data for establishing new effluent limitations.
Conducting Toxicity Tests
A toxicity testing program is conducted by the regulatory agency to
evaluate an effluent. The toxicity tests can be conducted on- or off-
site.
On-site biomonitoring may involve the following toxicity tests:
• Acute toxicity tests
- An 8- to 24-hour range-finding (screening) test
- A 24- to 96-hour static test
- A 96-hour, flow-through test
- A 24-hour quality assurance test with a referenced toxicant
- Other effluent testing (e.g., fractionation, persistence).
• Chronic toxicity tests
- Range-finding tests
- Acute tests with a reference toxicant (run concurrently with a
chronic test)
NPDES Inspection Manual 7-9 January 1988
-------
Chapter Seven Biomonitoring
- Short-term chronic tests (either static, static renewal, or
flow-through)
- Other effluent testing procedures (e.g., instream toxicity,
relative toxicity).
Off-site biomonitoring usually involves:
0 Collecting an effluent sample (a grab sample or a 24-hour composite
sample)
0 Transporting the sample to EPA or to State laboratories
0 Performing any of the above tests.
Effluent Sampling and Holding
The effluent sampling point must be the same as that specified in the
NPDES permit. However, different locations may be used to evaluate
individual wastestreams. A sample should represent the "normal and
typical" discharge and operating conditions of the facility. Toxicity
tests should be initiated within 36 hours of sample collection for non-
persistent effluents and within 72 hours for persistent effluents
(EPA/600/4-85/013).
Effluent variability may be estimated from a review of self-monitoring or
by continuously monitoring parameters such as pH or conductivity. From
these data, a mean and standard deviation may be calculated (Note pH is
logarithmic). If the coefficient of variability (i.e., the standard
deviation divided by the mean) exceeds 0.5, the wastewater is highly variable.
This variability should be addressed in the type of exposure during the
test (flow through versus static) as well as the sample collection regime
used.
Effluent grab samples must be stored in covered, unsealed containers.
Although it is desirable to refrigerate samples before testing them,
it is often convenient to store them in a constant-temperature water bath
or controlled environment room at the temperature at which the test will
be conducted. The test should be initiated as soon as possible, but no
later than 36 hours (or 72 hours, if persistent) after sample collection.
The persistence of an effluent's toxicity may be a factor in determining
specific toxicity limits in a NPDES permit, and it is determined by
measuring the effluent toxicity at collection and again after holding the
sample for 96 hours. If after holding the effluent 96 hours its toxicity
has not decreased by 50 percent or more, it is classified as persistent.
(When special tests such as persistence are conducted, the exact methodology
must be detailed in the report.)
Flow-through Tests. These procedures are generally appropriate for acute
tests. If the permittee facility discharges continuously, the effluent
should be pumped directly and continuously from the discharge line to the
dilutor system for the duration of the test. If the effluent cannot be
pumped directly and continuously to the dilutor system, the following
alternative methods may be used to collect it:
NPDES Inspection Manual7-10January 1988
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Chapter Seven Biomonltorlng
• When the calculated retention time of the effluent is less than
14 days, a minimum of two grab samples are collected daily (e.g.,
8:00 a.m. and 4:00 p.m.). The freshly collected effluent should
not be combined with effluent remaining from a previously collected
sample. The remainder of the previously collected sample is
discarded, and the container is refilled with fresh effluent.
• When the calculated retention time of the effluent is 14 days or
greater, a single grab sample of sufficient volume to supply the
dilutor for 24 hours is collected daily. The volume of the sample
remaining from the previous day is discarded and replaced by the
fresh sample (renewal).
If the permittee's discharge is intermittent, use one of the following
procedures:
• When a continuous discharge occurs during a single 8-hour work
shift or two successive 8-hour work shifts, at least one grab
sample of sufficient volume to supply the dilutor for 24 hours
is collected daily, midway in the discharge period.
t When the facility retains the wastewater during an 8-hour work
shift, and then treats and releases it as a batch discharge, a
single grab sample of sufficient volume to last 24 hours is
collected daily from each discharge during the test period.
t When the facility discharges wastewater to an estuary only during
an outgoing tide, a single grab sample of sufficient volume to
last 24 hours is collected during one discharge period every 24
hours for the duration of the test. An alternative sampling
method would be to place the effluent sampling pump in the final
waste lagoon adjacent to the discharge pipe so that a continuous
source of effluent would be available for testing.
Static Tests. Static tests are appropriate for both acute and chronic
testing.STmpling recommendations are discussed for both types of static
test conditions—nonrenewal and renewal. For nonrenewal conditions
appropriate for some acute testing, effluent samples are collected only
at the beginning of the effort. For renewal tests appropriate for non-
persistent effluents and most chronic toxicity tests, samples are collected
to renew the test solutions regularly throughout the test period.
If the facility discharge is continuous, use one of the following approaches
• If the calculated retention time is less than 14 days and the
variability of the waste is unknown, use one of the approaches
identified below:
- Nonrenewal tests: A minimum of two separate grab samples are
collected over the first 24-hour period and used in separate
tests to determine the variability in toxicity by comparison of
the results
NPDES Inspection Manual 7-11 January 1988
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Chapter Seven Blomonitorlng
- Renewal tests: A minimum of two separate grab samples are
collected over the first 24-hour period. Each sample is used
in a separate test that begins on the first day and is renewed
daily.
• If the calculated retention time is greater than 14 days, or if
it can be demonstrated that the wastewater does not vary in
chemical composition or concentration regardless of holding time,
use one of the following approaches:
- Nonrenewal tests:. A minimum of one grab sample is collected
and used in a single test
- Renewal tests: A minimum of one grab sample is collected each
day, or as specified in the test procedure, and used to renew
the test solutions.
If the facility discharge is intermittent, use one of the following
approaches:
• When the effluent is discharged continuously during a single
8-hour work shift or two consecutive 8-hour work shifts, a minimum
of one grab sample is collected midway in the discharge period
and used in a single nonrenewal test, or a grab sample may be
collected daily for a renewal test.
t When the facility retains the wastewater during an 8-hour work
shift, then treats and releases it as a batch discharge, a grab
sample is collected for a single nonrenewal test, or a grab
sample is collected daily for a renewal test.
• When the facility discharges wastewater to an estuary only during
an outgoing tide, a grab sample is collected during a discharge
period for use in a single nonrenewal test, or a grab sample is
collected daily for a renewal test.
• At the end of the shift, cleanup activities may result in the
discharge of a slug of toxic waste. It would be advisable,
therefore, to consider collecting a sample at that time and
conducting a separate toxicity test.
Test Organisms
The inspector should determine whether the following test organism criteria
are observed by the laboratory:
• Test organisms of the appropriate age are used. Juvenile fish
(one to 90 days old) are required (7-14 days are preferred) for
acute toxicity testing. Chronic toxicity tests with the fathead
minnow (Pimephales promelas) and the cladoceran (Ceriodaphnia
dubia) require neonates that are less than 24-hours old. A stock
culture 7- to 10-days old is preferred for chronic toxicity
testing with alga (Selenastrum capricornutum).
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Chapter Seven Blomonitoring
• Test organisms are fed according to the requirements for the
particular type of test:
- Problems caused by feeding, such as the possible alteration of
the toxicant concentration and the buildup of food and metabolic
wastes, with the concomitant increase in oxygen demand, are
common in static test systems. When feeding is necessary,
excess food should be removed daily by aspirating with a pipette.
- Feeding does not cause the above problems in flow-through
systems. However, it is advisable to remove excess food, fecal
material, and any solids that may have settled from the effluent
to the bottom of the test vessels daily by aspirating them with
a pipette.
• A daily log of feeding, mortality, and observations.
t Observes the following procedures for holding test organisms:
- Quarantines new test organisms for at least 10 days if received
from an outside source of unknown quality or 48 hours if test
organisms are obtained from a quality stock.
- Ensures a gradual acclimation. Maximum changes permitted are
3°C in water temperature, or 3 0/00 in salinity in a 12-hour
period; or total change of 6°C, 6 0/00 salinity or 2.0 pH units.
- Maintains DO levels above 40 percent saturation for warm water
species and above 60 percent saturation for cold water species.
t Records source of test organisms (hatchery, in-house, or elsewhere),
as well as holding conditions (temperature, dissolved oxygen).
• Handles test organisms as little as possible to minimize stress:
- Dip nets should be used for large organisms
- Pipettes should be used for transferring small organisms such
as daphnids and midge larvae.
Facility and Equipment
General Requirements. Effluent toxicity tests may be done in a fixed or
mobile laboratory. Depending on the scope of the toxicity testing program,
facilities may include equipment for rearing, holding, and acclimating
organisms. Temperature control is achieved using circulating water
baths, heat exchangers, or environmental chambers. Appropriate dilution
water may be ground water, surface water, reconstituted water, or dechlori-
nated tap water. Holding, acclimation, and dilution water should be
temperature controlled and aerated whenever possible. Air used for
aeration must be free of oil and fumes; filters to remove oil in water
are desirable. Test facilities must be well ventilated and free of
fumes. During holding, acclimating, and testing, test organisms should
be shielded from external disturbances.
NPDES Inspection Manual 7-13 January 1988
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Chapter Seven Blomoniton'ng
Some organisms may have special environmental requirements, such as
flowing water, fluctuating water levels, or particular substrate, that
must be provided. During holding, acclimating, and testing, immature
stream insects always should be in flowing water, as described by Nebeker
and Lemke (1968); peneid shrimp and bottom-dwelling fish should be provided
a sandy substrate. Since cannibalism can occur among many species of
arthropods, these organisms should be isolated by some means (e.g., with
screened compartments). The claws of crabs and crayfish should be bound.
Construction Materials. Tempered glass, No. 304 (for freshwater) or No.
316 or higher (for salt water) stainless steel, and perfluorocarbon
plastics (TEFLON®) should be used in the construction of test equipment
whenever possible. Linear polyethylene also may be used with some types
of effluents, but it should be avoided with effluents containing synthetic
organic compounds or pesticides. Unplasticized plastics, such as poly-
ethylene, polypropylene, TYGON®, and fiberglass, can be used for holding,
acclimating, and dilution-water storage tanks, and in the water delivery
system. Copper, galvanized material, rubber, brass, and lead must not
contact holding, acclimation, or dilution water, or effluent samples and
test solutions.
Effluent Delivery System (Flow-through Test Only). The flow-through
proportional-diTutor delivery system has proved the best system for
routine effluent toxicity tests conducted in fixed and mobile laboratories.
Dilutors with a solenoid valve system are preferred, but the vacuum
siphon system is acceptable if funds are limited.
The flow rate through the proportional dilutor must provide for at least
5 complete water changes in 24 hours per chamber, plus sufficient flow to
maintain an adequate DO concentration. The flow rates through the test
chambers should not vary by more than 10 percent among test chambers at
any time during any test. The dilutor also should be capable of maintaining
the test concentration in each test chamber within 5 percent of the
initial value for the test duration. The dilutor should be checked and
calibrated before and after each test.
Test Chambers. Test chambers used in flow-through tests usually are
constructed of one-fourth inch plate glass held together with clear
silicone adhesive. All joints should be smooth. Stainless steel (No.
304 or No. 316) can be used in the construction of test chambers, but it
must be welded, not soldered. Plastic chambers can be used, but they
may be rinsed with dilution water prior to testing and should be discarded
after the test.
Test chambers most commonly used in static tests are widemouthed 3.8-
liter (1-gallon) or 19.0-liter (5-gallon) soft-glass bottles or aquariums.
Short-term subchronic toxicity test materials for Ceriodaphnia dubia
include the use of unwashed disposable plastic. Containers such as 10-
to 20-cm diameter culture dishes or beakers may be more suitable as test
chambers for fish eggs and/or larvae and small crustaceans. Special glass
or stainless steel test chambers can be constructed to accommodate test
organisms requiring special physical conditions. These chambers should
be covered and provided with 5 cm of test solution. Algal tests require
constant but gentle agitation or shaking in special culture flasks.
NPDES Inspection Manual 7-14 January 1988
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Chapter Seven Blomonltoring
Dilution Water. The source of dilution water used in the tests will
depend largely on the objectives of the study. It is recommended that a
standard dilution water be used to determine the inherent toxicity of the
effluent or to monitor compliance with a limit. For on-site flow through
tests, such large quantities of water are required that upstream receiving
waters or ground water sources are most practical. If the objective of
the test is to determine the effect of multiple point sources, it is
desirable to use receiving water as the dilution water even when it is
contaminated by "upstream" sources of toxic substances. In this case, an
uncontaminated dilution water source must be used as the control to
distinguish between observed toxicity due to the effluent and that due to
the dilution water.
When the dilution water is taken from the receiving water, it should be
collected at a point as close as possible to the outfall, but upstream
from or outside of the influence of the effluent. In an estuary, the
dilution water should have the same salinity as water at the receiving
site. It should be collected at slack high tide or within 1 hour after
high tide. The water should be collected immediately before the test,
and never more than 96 hours earlier. The sample should be chilled to
4°C during or immediately after col lection and maintained at that temperature
until used.
If contaminant-free water is required for acute toxicity testing, dilution
water is acceptable if healthy organisms survive in it without showing
stress and their mortality does not exceed 10 percent during the acclima-
tion period. Dilution water is considered acceptable for chronic toxicity
testing if test organisms show adequate survival, growth, and reproduction
in the controls during the study.
Except for chronic toxicity testing, pretreatment of dilution water should
be limited to filtration through a nylon sieve having 2- to 4-millimeter
openings to remove debris and/or break up large floating or suspended
solids. If a mini-dilutor employing capillary delivery tubes is used, it
may be necessary to filter the effluent through glass wool before it
enters the diTutor system. With Ceriodaphnia and Pimephales (fathead
minnow) tests, effluents and surface waters must be filtered through a
30-micron plankton net to remove indigenous organisms that could attack
the test organisms. Surface waters used in algal toxicity tests must be
filtered through a 0.45-micron pore diameter filter before use.
If the receiving water is unsuitable to use as dilution water, use "recon-
stituted" water. Saltwater media such as INSTANT OCEAN®, 40 fathoms*,
and Hawaiian Mix* are available commercially. Recommended procedures for
preparing "reconstituted" water are given in Methods for Measuring the
Acute Toxicity of Effluents to Freshwater and Marine Organisms (EPA
600/4-85/013) and Methods for Estimating the Chronic Toxicity of Effluents
and Receiving Waters to Freshwater Organisms (EPA 600/4-85/014).
Test Procedures
Range-finding (Screening) Test. It may be necessary to conduct an
abbreviated, preliminary, range-finding, or screening test to determine
the concentrations necessary for definitive tests. Screening can be
NPDES Inspection Manual7-15January 1988
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Chapter Seven Biomonitorin^
a static or a flow-through test. Static tests use five organisms in
3 to 5 effluent dilutions and a control, for 8 to 24 hours. If
the range-finding test is to be conducted with the same sample of effluent
as that used in the definitive test, the duration of the range-finding
test cannot exceed 24 hours and the definitive test must begin within 36
hours of sample collection.
Definitive Test. The determination of the adverse effects of toxicants
must employ a control and at least five concentrations of effluent in an
exponential series.
If 100 percent effluent does not, in an acute toxicity test, kill (or
affect) more than 50 percent of the organisms exposed to it, the percentage
of organisms killed (or affected) by various levels of the effluent in
the receiving water must be reported. A test is not acceptable if control
mortality exceeds 10 percent in controls for acute tests and 20 percent
overall for chronic tests.
Chronic tests generally are used to establish "no effect" levels of
effluents or mixtures of effluents and receiving waters. Although the
chronic testing is designed to evaluate quantifiable changes in such
characteristics as growth or reproduction, qualitative observations or
differences in behavior or appearance are also important. Appropriate
test procedures must be used and acceptable conditions maintained through-
out the test for the results to be valid.
Number of Test Organisms. For acute toxicity testing, at least 20
organisms of a given species must be exposed to each treatment in two or
more replicates. The numbers vary for chronic toxicity testing, from 1
Ceriodaphnia in 10 replicates for a survival and reproduction test to 20-
50 fathead minnow embryos (Pimephales promelas) in 2 replicates for a
survival and teratogenicity test. An initial cell density of 10,000
cells/ml is required in three replicates for the alga (Selenastrum
capricornutum) growth test. To qualify as true replicates, no water
connection can exist between replicate test chambers.
Loading of Test Organisms (Acute Tests). For flow-through tests, loading
in the test chambers must not exceed 5 grams per liter at temperatures of
20°C or less, or 2.5 grams per liter at temperatures above 20°C.
For both renewal and nonrenewal static tests, loading in the test chambers
must not exceed 0.8 grams per liter at temperatures of 20°C or less and
0.4 grams per liter at temperatures above 20°C.
Water Temperature. Maintain the water temperature within +2.0°C of the
recommended temperature except for Ceriodaphnia. for which the temperature
must be kept +_1°C of the specified level.
Dissolved Oxygen. Avoid aeration that may alter the results of toxicity
tests.However, the DO concentration in the test solution must exceed 40
percent saturation for warm water species and 60 percent saturation for
cold water species. The turnover rate of the solutions in the test chambers
may be increased to maintain acceptable DO levels. If the increased
turnover rate does not maintain adequate DO levels, dilution water must
be aerated. For effluents with chronically low DO, flow through testing
is recommended rather than aeration. Aeration is only a last resort.
NPDES Inspection Manual7-16January 1988
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Chapter Seven Blomonlton'ng
Synthetic Water. Synthetic moderately hard water (hardness of 80 to 100
my/I as CaC03) is recommended as a standard medium for tests using
Cen'odaphnia. MiliQ® or equivalent types of water treatment are recom-
mended to provide adequate quality for dilution water.
Beginning the Test. The test begins when the test organisms are first
exposed to the effluent.
• Flow-through test: The dilutor system should be in operation 24
hours before test organisms are added and the test begins. During
this period, effluent volumes, temperature, and flow rates are
adjusted.
• Static test: The effluent is added to the dilution water and
mixed well by stirring with a glass rod. The test organisms are
placed in the chambers within 30 minutes.
Feeding the proper amount of the right food is extremely important in
Ceriodaphnia culturing. The key is to provide sufficient nutrition to
support normal reproduction without adding excess food that might clog
the animal's filtering apparatus, or greatly decrease the concentration
of DO, and cause the animals to die. Feeding procedures for Ceriodaphnia
are detailed in Methods for Estimating the Chronic Toxicity of Effluents
and Receiving Waters to Freshwater Organisms (EPA 600/4-85/014).
Duration. Depending on the test organisms used, the purpose of the test,
and the type (range-finding or definitive), the duration of acute toxicity
tests may range from 8 to 96 hours. Methodology now permits short-term
(4- to 8-day) chronic toxicity tests.
Reference Toxicants
Reference toxicants are used to establish the relative sensitivity of the
test organisms. A laboratory performs a definitive 24- or 48-hour static
toxicity test with the reference toxicant to establish an average response.
The LC50 of a batch of test organisms can be evaluated against the laboratory's
control charts (USEPA 1979). For example, if the LC50 of a reference
toxicant is not in the recommended range for the test organism, the
sensitivity of the organism and/or the credibility of the test system are
suspect.
Three reference toxicants are available from EPA Environmental Monitoring
Systems Laboratory (EMSL), Cincinnati, OH. An attempt should be made to
match the type of toxicant used (e.g., metal or chlorinated organic) to
the major pollutant in the wastewater tested.
Chain-of-Custody and Preservation of Documents
Results obtained by persons having expertise in conducting sampling and
biomonitoring are valid. Normal EPA chain-of-custody procedures should
be used. However, an additional effort in custodial care is required to
ensure the admission of biomonitoring information in enforcement proceedings.
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Chapter Seven Biomonitorlng
For on-site biomonitoring, chain-of-custody records are those that show
the source of the materials tested and that indicate that test results
are not inaccurate because of deliberate tampering or unintentional
error.
For off-site biomonitoring, chain-of-custody consists of records and/or
labels, a field data sheet, and/or a field logbook showing where, when,
and by whom a sample was taken and the persons to whom custody was
relinquished throughout the sampling and testing process. It also includes
appropriate notations in the laboratory logbook listing the names of
sample custodians, as well as notations on the security measures taken to
protect the integrity of the sample during testing.
Data Reporting
The primary purpose of a compliance biomonitoring inspection is to
establish permittee compliance status with biomonitoring requirements in
a NPDES permit and/or to evaluate the effluent's potential for toxicity
to aquatic life in the receiving waters. This is accomplished by comparing
the permittee biomonitoring data collection and analysis procedures with
the permit conditions. Comparisons could include the following types of
data:
• Toxicity of the waste (LC50 or EC50) expressed as a percent
dilution
• Instream waste concentration (IWC) of the effluent
• No-Observed-Effect-Level (NOEL)
• Potential for chronic and acute toxicity of waste in the receiving
water, including persistence, carcinogenicity, mutagenicity, and
teratogenicity
t Permit limits, if contained in the permit, or State Water Quality
Standards for toxicity
• Chemical parameters of effluent measured in conjunction with the
toxicity test, such as DO, temperature, pH, conductivity, metals, and
organics.
The following types of effluent biomonitoring results must be recorded:
• Biological data, including length, weight, and/or age of test
organisms and number of test organisms affected.
• Physical and chemical data, including DO, temperature, pH, specific
conductivity, total alkalinity, hardness, salinity, and total
ammonia nitrogen.
• Reference toxicant data
• Effects measured in each test concentration and control--LC50,
EC50, and their 95 percent confidence limits.
NPDES Inspection ManualT^TSJanuary 1988
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Chapter Seven Biomonitoring
• End points for chronic tests that may include the levels.of effluent
causing significant changes in metabolic rates, survival, growth,
production of young, or even behavior. These may be expressed as
effective concentrations (EC1, EC50), no effect levels, or maximum
allowable toxicant concentrations.
A report of the results of a biomonitoring test must include the elements
listed under "Recordkeeping and Data Recording."
Definitions
ACUTE Involves a stimulus severe enough to rapidly induce a response.
In toxicity tests, a response observed in 96 hours or less typically is
considered acute. An acute effect is not always measured in terms of
lethality; it can be expressed as a variety of effects. Note that acute
means SHORT, not mortality.
ACUTE-CHRONIC RATION (ACR) Ratio of the acute toxicity (expressed as an
LC50) of an effluent or a toxicant to its chronic toxicity (expressed as
NOEL). It is used as a factor for estimating chronic toxicity on the
basis of acute toxicity data.
ADDITIVITY The characteristic property of a mixture of toxicants that
exhibits a cumulative effect equal to the arithmetic sum of its components.
BIOACCUMULATION Uptake and retention of substances by an organism from
its surrounding medium and from food.
BIOASSAY A test used to evaluate the relative potency of a chemical by
comparing its effect on a living organism with the effect obtained from a
standard preparation on the same organism type. Bioassays are frequently
used in the pharmaceutical industry to evaluate potency of vitamins and
drugs. "Bioassay" and "toxicity test" are not synonymous.
BIOCONCENTRATION Uptake of substances from the surrounding medium through
gill membranes or other external body surfaces.
CHRONIC Involves a stimulus that lingers or continues for a relatively
long period, often one-tenth of a lifespan or more. Chronic should be
considered a relative term depending on the lifespan of an organism. A
chronic effect can be lethality, growth, reduce reproduction, etc.
Chronic means LONG.
CRITICAL LIFE STAGE The period in an organism's lifespan in which it is
the most susceptible to adverse effect caused by exposure to toxicants,
usually occurring during early development (egg, embryo, larvae). Chronic
toxicity tests are often done at critical life stages to mimic long
duration , life cycle tests.
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Chapter Seven Biomonitoring
EFFLUENT BIOMONITORING Measurement of biological effects of effluent
(e.g., toxicity, biostimulation, and bioaccumulation).
FINAL ACUTE VALUE (FAV) An estimate of the concentration of a chemical
that corresponds to the 95th percentile of LCso values obtained for a
chemical with different genera of aquatic organisms. The FAV is used for
criteria development.
LC50 Toxicant concentration killing 50% of exposed organisms at a specific
time of observation.
LOG NORMAL PROBABILISTIC DILUTION MODEL Model that calculates probability
distribution of receiving water quality concentrations from log normal
probability distributions of the input variables.
NO OBSERVED EFFECT LEVEL (NOEL) Highest measured continuous concentration
of an effluent or a toxicant that causes no observed effect on a test
organism.
PERSISTENCE Property of a toxicant or an effluent that is a measurement
of the duration of its effect. A persistent toxicant or toxicity maintains
its effect after mixing, degrading slowly. A nonpersistent toxicant or
toxicity may have a quickly reduced effect after mixing as degradation
processes such as volatilization and photolysis transform the chemical.
PROBABILITY Number expressing the likelihood of occurrence of a specific
event, such as the ratio of the number of outcomes that will produce a
given event to the total number of possible outcomes.
SUBLETHAL Involves a stimulus below the level causing death.
SYNERGISM Characteristic property of a mixture of toxicants that exhibits
a greater-than-additive cumulative toxic effect.
TOXICITY TEST The means to determine the toxicity of a chemical or an
effluent with the use of living organisms. A toxicity test measures the
degree of response of an exposed test organism to a specific chemical or
effluent.
TOXIC UNIT ACUTE (TUa) Reciprocal of the effluent dilution that causes
the acute effect by the end of the acute exposure period.
TOXIC UNIT CHRONIC (TUC) Reciprocal of the effluent dilution that causes
no unacceptable effect on the test organisms by the end of the chronic
exposure period.
WHOLE-EFFLUENT TOXICITY Aggregate toxic effect of an effluent measured
directly with a toxicity test.
NPDES Inspection Manual 7-20 January 1988
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Chapter Seven Biomonitorlng
References
Davey, E.W., et al. 1979. "Retrieval of Trace Metals from Marine Culture
Media." Limnol. Oceanog. 15:486-488.
Kester, D.R., et al. 1967. "Preparation of Artificial Seawater."
Limnol. Oceanog. 12:176-179.
Marking, L.L., and V.K. Dawson. 1973. "Toxicity of Quinaldine Sulfate
to Fish." Invest. Fish Contr. No. 48, U.S. FWS, Washington, D.C. 8 pp.
Nebeker, A.V., and A.E. Lemke. 1968. "Preliminary Studies on the
Tolerance of Aquatic Insects to Heated Waters." J. Kans. Entomol. Soc.
41:413-418.
U.S. Environmental Protection Agency. 1979. Handbook for Analytical
Qua!ity Assurance in Water and Wastewater Laboratories.Environmental
Monitoring and Support Laboratory. Cincinnati, Ohio.EPA 600/4-79-019.
U.S. Environmental Protection Agency. 1985a. Methods for Estimating
the Chronic Toxicity of Effluents and Receiving Waters to Freshwater
Organisms. EPA-600/4-85-014.
U.S. Environmental Protection Agency. 1985b. Methods for Measuring
the Acute Toxicity of Effluents and Receiving Waters to Freshwater
Organisms.EPA-600/4-85-013.
U.S. Environmental Protection Agency. 1985c. Technical Support Document
for Water Quality-Based Toxics Control. Office of Water Enforcement and
Permits and Office of Water Regulations and Standards, Washington, D.C.
Zaroogian, G.E., G. Pesch, and G. Morrison. 1969. "Formulation of an
Artificial Seawater Media Suitable for Oyster Larvae Development." Amer.
Zool. 9:141.
Zillinoux, E.J., et al. 1973. "Using Artemia to Assay Oil Dispersant
Toxicities." J. Water Poll. Fed. 45:2389-2396.
NPDES Inspection Manual 7-21 January 1988
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Chapter Eight
LABORATORY QUALITY ASSURANCE
Contents Page
A Objectives and Requirements 8-1
B Sample Handling Procedures
Evaluation of Permittee Sample Handling Procedures 8-3
C Laboratory Analyses Techniques Evaluation
Evaluation of Permittee Laboratory Analytical Procedures .... 8-5
Evaluation of Permittee Laboratory Facilities and Equipment . 8-6
Laboratory Services 8-6
Instruments and Equipment 8-6
Supplies 8-7
D Quality Assurance and Quality Control
Evaluation of the Precision and Accuracy of the Permittee
Laboratory 8-9
Evaluation of Permittee Data Handling and Reporting 8-10
Evaluation of Permittee Laboratory Personnel 8-11
Evaluation of Contract Laboratories 8-11
Overview of the Discharge Monitoring Report Quality Assurance
Program and How it Relates to the Inspection Program 8-11
Highlights 8-12
E References and Laboratory Quality Assurance Checklist
References 8-13
Laboratory Quality Assurance Checklist 8-15
NPDES Inspection Manual8-iJanuary 1988
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Chapter Eight
A OBJECTIVES AND REQUIREMENTS
The analytical laboratory provides both qualitative and quantitative informa-
tion for determining the extent of permittee compliance. To be valuable or
useful, the data must accurately describe the characteristics and concentrations
of constituents in the samples submitted to the laboratory. The objectives
of laboratory quality assurance (QA) are to monitor the accuracy and precision
of the results reported and to meet reliability requirements.
QA refers to a total program for ensuring the reliability of data by utilizing
administrative procedures and policies regarding personnel, resources, and
facilities. QA is required for all functions bearing on environmental measure-
ments and includes activities such as: project/study definition; sample
collection; laboratory analysis; data validation, analysis, reduction, and
reporting; documentation; and data storage systems. Thus, the QA program is
designed to evaluate and maintain the desired quality of data. Quality
control (QC), a function of QA, is the routine application of procedures for
controlling the accuracy and precision of the measurement process and includes
the proper calibration of instruments and the use of the appropriate analytical
procedures.
Laboratory QA is required by 40 CFR Section 122.41(e), which states that
adequate laboratory and process controls, including appropriate QA procedures,
must be provided. Each permittee's laboratory should have a QA program. The
QA program should be documented in a written QA manual distributed to all
personnel responsible for analyses. This manual should identify clearly the
individuals involved in the QA program and their responsibilities, and should
document the laboratory's standard operating procedures that meet user require-
ments in terms of specificity, completeness, precision, accuracy, representa-
tiveness, and comparability.
Guidance in this chapter is broad based and may not be applicable to every
laboratory. A Laboratory Quality Assurance Checklist for the inspector's use
is included at the end of this chapter. For detailed information concerning
laboratory QA, refer to EPA's Handbook for Analytical Quality Control in
Water and Wastewater Laboratories (USEPA 1979a).
NPDES Inspection Manual8^1January 1988
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Chapter Eight
B SAMPLE HANDLING PROCEDURES
Evaluation of Permittee Sample Handling Procedures
Proper sample handling procedures are necessary in the laboratory from the
sample's receipt until it is discarded. Sample handling procedures for small
permittee's may differ from procedures for larger permittee's because staff
organizational structures and treatment facility designs vary from one facility
to the next. However, proper sample handling procedures should be utilized
and documented by all permittee's in order to produce evidence that may be
used in an enforcement action. In evaluating laboratory sample handling
procedures, the inspector should verify that:
• The laboratory has a sample custodian
• The laboratory area is a secured area and is restricted to
authorized personnel only
• The laboratory has a sample security area that is dry, clean,
and isolated; has sufficient refrigerated space; and can be locked
securely
0 Samples are handled by a minimum number of people
§ All incoming samples are received by the custodian, who signs the
chain-of-custody record sheet accompanying the samples and retains
the sheet as a permanent record
• The custodian has ensured that samples are properly stored
t Only the custodian distributes samples to personnel who are to
perform analyses
• Care and custody records for handling samples are accurate and up-to-
date.
NPDES Inspection ManualgTJJanuary 1988
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Chapter Eight
C LABORATORY ANALYSES
TECHNIQUES EVALUATION
Evaluation of Permittee Laboratory Analytical Procedures
The methods used by permittee laboratories must be uniform, thus, eliminating
methodology as a variable when data are compared or shared among laboratories,
Procedures used by the permittee's laboratory must be selected by consulting
40 CFR Part 136 or EPA for approval of alternative methods. Alternative test
procedures may be implemented only if the required written EPA approval has
been obtained, as specified by 40 CFR Parts 136.4 and 136.5, and promulgated
under P.L. 92-500.
Many standardized test procedures that have been promulgated under 40 CFR
136 are covered in Methods for Chemical Analysis of Water and Wastes (USEPA
1979b). Revisions and new additions to this publication are made whenever
new analytical techniques or instruments are developed. These are considered
accepted after publication in the Federal Register. Other acceptable
methods are specified in the latest accepted edition of Standard Methods
for the Examination of Water and Wastewater, the Annual Book of Standards,
Part 31. Water (APHA, AWWA. and WPCF).ffFe most current 40 CFR Part 136
may supercede any method or technique cited in this manual.)
In evaluating laboratory analytical procedures, the inspector should verify
that:
• Analytical methods specified in 40 CFR Part 136 are followed and
any deviations allowed by 40 CFR Part 136 are probably performed
t The QC system used conforms to the system specified in the permit,
or detailed in published Standard Methods (APHA, AWWA, and WPCF)
or 40 CFR Part 136
• A QC record is maintained on reagent preparation, instrument
calibration and maintenance, and purchase of supplies
• QC checks are made on materials, supplies, equipment, instrument
calibration and maintenance, facilities, analyses, and standard
solutions
• Steps and procedures stated in the method specified in 40 CFR Part
136 are followed
• Documentation of any EPA-approved deviation from specified test
procedures is available.
NPDES Inspection Manual 8-5 January 1988
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Chapter Eight Laboratory Quality Assurance
Evaluation of Permittee Laboratory Facilities and Equipment
To verify that the proper analytical procedures are being followed, the
inspector should have the responsible analyst describe each of the procedures.
The inspector should be alert to any deviation from the specified analytical
method. Any questions regarding the proper procedures can be resolved by
referring to the cited methodology. Even simple analyses can yield invalid
results if the methodology cited in 40 CFR Part 136 is not exactly followed.
Laboratory Services
The availability of laboratory services affects data reliability. The inspector
should verify that the following items are provided:
• An adequate supply of laboratory pure water, free from chemical
interferences and other undesirable contaminants. Water quality
should be checked routinely and documented.
• Adequate bench, instrumentation, storage, and recordkeeping
space.
Adequate humidity and temperature control.
Adequate lighting and ventilation.
Dry, uncontaminated, compressed air when required.
Efficient fume hood systems.
Necessary equipment such as hot plate, refrigerator for samples, pH
meter, thermometer, and balance.
0 Electrical power for routine laboratory use and, if appropriate,
voltage-regulated sources for delicate electronic instruments.
t Emergency equipment, fire extinguisher, eye wash station, shower,
first aid kit, gloves, and goggles.
0 Vibration-free area for accurate weighings.
Instruments and Equipment
Instrumentation is extremely important in the analytical laboratory. To a
certain extent, analytical instrumentation is always developmental; manufac-
turers are continually redesigning and upgrading their products, striving for
miniaturization, enhanced durability and sensitivity, and improved automation.
In evaluating laboratory instruments and equipment, the inspector should
veri fy that:
• Standard and specific procedures for cleaning glassware and
containers are followed.
t Written requirements (e.g., instruction manuals) for daily operation
of instruments and equipment are provided and followed.
0 Standards and appropriate blanks are available to perform standard
calibration procedures. Standard concentrations which closely bracket
actual sample concentrations should be used.
NPDES Inspection Manual8^6January 1988
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Chapter Eight Laboratory Quality Assurance
• Written troubleshooting procedures are available.
• Written schedules for replacement, cleaning, checking, and/or
adjustment by service personnel are available and followed.
Maintenance of laboratory facilities and equipment is an important factor in
laboratory QA.
Supplies
Chemical reagents, solvents, and gases are available in many grades of
purity, ranging from technical grade to various ultrapure grades. The
purity of the materials required in analytical chemistry varies with the
type of analysis. The parameter being measured and the sensitivity and
specificity of the detection system determine the purity of the reagents
required. Reagents of lesser purity than that specified by the method
should not be used. In evaluating laboratory supplies, the inspector
should verify that:
• The required reagent purity for the specific analytical method is
used
t Standard reagents and solvents are stored according to the
manufacturer's directions
• Working standards are checked frequently to determine changes in
concentration or composition
• Concentrations of stock solutions are verified before being used to
prepare new working standards
• Laboratory supplies with limited shelf-life are dated upon receipt
and shelf-life recommendations, including the discard date on the
container and the storage requirements, are observed
• Reagents are prepared and standardized against reliable primary
standards
t Standards and reagents are labeled properly.
NPDES Inspection Manual 8-7 January 1988
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Chapter Eight
D QUALITY ASSURANCE AND QUALITY
CONTROL
Evaluation of the Precision and Accuracy of the Permittee Laboratory
The purpose of laboratory control procedures is to ensure high-quality analyses
by the use of control samples, control charts, reference materials, and
instrument calibration. Controls must be initiated and maintained throughout
the analysis of samples. Specifically, each testing batch must contain at
least one blank, standard duplicate, and spiked (as applicable) sample
analysis. When a batch contains more than ten samples, every tenth sample
should be followed by a duplicate and a spike (as applicable).
The precision of laboratory findings refers to the reproducibility of esti-
mated replicate observations. In a laboratory QC program, precision is
estimated by the analysis of actual samples in duplicate. These may represent
a range of concentrations. Accuracy refers to the degree of difference
between observed values and known or actual values. The accuracy of a method
may be determined by analyses of samples to which known amounts of reference
standards have been added (spiked samples).
In evaluating the precision of the measurement process, the inspector should
veri fy that:
• Control samples are introduced into the train of actual samples to
monitor the performance of the analytical system.
t Duplicate analyses are performed with each batch of samples to
determine precision. In general, ten percent of the sample should be
duplicated.
• Precision control charts or other statistical techniques for each
analytical procedure are prepared and used. Statistical methods
include calculation of mean, standard deviation, and variance to
define the range and variability of the data.
• Corrective actions are taken when data fall outside the warning and
control limits.
• The out-of-control data or situation and the corrective action taken
are fully documented.
NPDES Inspection Manual 8-9 January 1988
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Chapter Eight
Laboratory Quality Assurance
In evaluating accuracy, the inspector should verify that:
• Spiked samples are introduced into the train of actual samples at
least ten percent of the time to monitor the performance of the
analytical system.
t Spiked samples are used to monitor accuracy in each sample batch.
- The amount of additive is appropriate to the detection limit
and sample concentration.
• Accuracy control charts for each analytical procedure are prepared
and used.
- Accuracy limits are established based on standard deviations
whose upper and lower control limits are established at three
times the standard deviation above and
The upper and lower warning limits are
standard deviation above and below the
Some
136.
Corrective actions are taken when data
and control limits.
The out-of-control data or situation and
taken are fully documented.
below the central line.
established at twice the
central line. Note:
parameters have a defined warning limit required by 40 CFR
fall outside the warning
the corrective action
Evaluation of Permittee Data Handling and Reporting
An analytical laboratory must have a system for uniformly recording,
processing, and reporting data. In evaluating permittee data handling
and reporting, the inspector should verify that:
Correct formulas are used to calculate the final results.
Round-off rules are uniformly applied.
Significant figures are established for each analysis.
Provisions are available for cross-checking calculations.
Control chart approaches and statistical calculations have been
determined for the purposes of QC and reporting.
The report forms provide complete data documentation and permanent
recording and facilitate data processing.
The program for data handling provides data in the form/units
required for reporting.
Laboratory records are kept readily available to the regulatory
agency for a minimum of 3 years.
Laboratory notebooks or pre-printed data forms are bound permanently
to provide good documentation, including the procedures performed
and the details of the analysis, such as the original value recorded,
correction factors applied, blanks used, and the reported data
values. The notes are dated, indicate who performed the tests, and
include any abnormalities that occurred during the testing procedure.
The notes are retained as a permanent laboratory record.
NPDES Inspection Manua
3-10
January 1988
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Chapter Eight Laboratory Quality Assurance
^valuation ofPermittee laboratory Personnel
Analytical operations in the laboratory vary in complexity. Consequently,
work assignments in the laboratory should be clearly defined. All
analysts should be thoroughly instructed in basic laboratory operations.
Those persons performing complex analytical tasks should be qualified and
properly trained. All analysts must follow specified laboratory procedures
and be skilled in using the laboratory equipment and techniques required for
the analyses assigned to them. In evaluating laboratory personnel, the
inspector should consider the following factors:
t Adequacy of training
• Skill and diligence in following procedures
• Skill in using equipment and analytical methods
• Precision and accuracy in performing analytical tasks.
Evaluation of Contract Laboratories
When laboratories are contracted to analyze samples, the inspector may need
to assure that the laboratory practices at the contracted laboratory are also
evaluated. These can also be evaluated by other designated EPA inspectors.
If a deficiency is identified at a contracted laboratory, the permittee is
responsible for the deficiency and will be notified.
Overview of the Discharge Monitoring Report Quality Assurance Program
and How it Relates to the Inspection Program
The validity of the National Pollutant Discharge Elimination System (NPDES)
program depends on the quality of the self-monitoring program. The Discharge
Monitoring Report Quality Assurance (DMR QA) program is an important tool
used to ensure the quality of NPDES self-monitoring data. The program is
designed to evaluate and improve the ability of laboratories serving NPDES
permittees to analyze and report accurate self-monitoring data.
Major permittees under NPDES are sent performance evaluation samples contain-
ing constituents normally found in industrial and municipal wastewaters.
They are to analyze these samples using the analytical methods and laboratory
normally employed for their reporting of NPDES self-monitoring data. Respond-
ing permittees subsequently receive a report showing evaluation of their
reported data.
NPDES inspection Manual 8~TIJanuary 1988
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Chapter Eight Laboratory Quality Assurance
Highlights
0 The DMR QA Program has been an excellent means of focusing on and
improving the quality of laboratory results used in developing DMR
data. Improvements in the DMR QA data have been significant.
0 This program has helped major permittees identify and correct both
analytical and data handling problems in their laboratories.
t In general, permittees are receptive to the program and recognize
its value, including some who challenged EPA's authority to require
participation.
t Regions and States are generally supportive and have made good
use of the results of this program for targeting inspections and
directing other follow-up activities. This ability to concentrate
corrective actions on problem permittees results in an increased
efficiency in improving the self-monitoring data of all NPDES
permittees.
t The program is one of the least resource-intensive methods for
maintaining direct and regular technical contact with NPDES
permittees. It has been recognized as a cost-effective effort.
• Utilizing computer technology, the following ways of managing and
analyzing DMR QA data were started in FY 1985: compiling tracking
summaries, comparing performance of the major industries, tracking
multiple permittees, and regenerating past performance evaluation
reports.
The DMR QA Program and the NPDES inspection programs are interdependent in
several areas. First, in targeting the inspections, the DMR QA evaluations of
permittee performance can be used, since the evaluations identify potential
problems in laboratory analysis or data handling and reporting. This targeting
helps direct limited resources to permittees who need them most.
The inspections and DMR QA results are tracked and results are provided to the
DMR QA coordinators at EPA Regional Offices and NPDES States. To track follow-
up and complete statistical evaluations properly, a code is provided in the
Inspection Report Form to indicate when an inspection is the result of a DMR
QA evaluation. (This is shown with the Code Q on the inspection form.)
Finally, inspections, particularly the Performance Audit Inspection (PAI), can
be used to follow-up the DMR QA. The DMR QA results should be cross-checked
with the permit prior to the on-site visit, and parameters that were failed
should be stressed during a laboratory inspection.
NPOES Inspection Manual8-12January 1988
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Chapter Eight
E REFERENCES AND LABORATORY
QUALITY ASSURANCE CHECKLIST
References
American Society for Testing and Materials (ASTM). Annual Book of Standards,
Part 31, Water. ASTM, Philadelphia, PA.
APHA, AWWA, and WPCF. Standard Methods for the Examination of Water and
Wastewater. Use the most current, EPA-approved edition.
Brown, E., Skougstad, M.W., and Fishman, M.J. 1970. Methods for Collection
and Analysis of Water Samples for Dissolved Minerals aTid Gases. U.S.
Geological Survey Techniques of Water Resources Inv., Book 5.
Delfino, J.J. 1977. "Quality Assurance in Water and Wastewater Analysis
Laboratories". Water and Sewage Works. 124(7): 79-84.
U.S. Environmental Protection Agency. 1979a. Handbook for Analytical Quality
Control in Water and Wastewater Laboratories. EPA-600/4-79-019.
U.S. Environmental Protection Agency. 1979b. Methods for Chemical Analysis
of Water and Wastes. EPA-600/4-79-020.
Federal Register. Vol 51. No. 125, June 30, 1986. Guidelines Establishing
Test Procedures for the Analysis of Pollutants Under the Clean Water Act
(Also see October 26, 1986).
Plumb, R.H., Jr. 1981. "Procedure for Handling and Chemical Analysis of
Sediment and Water Samples." Technical Report EPA/CE-81-1.
USGS, USDI, Open File Report 85-495; 1906 (See 6/30/86 FR for full citation).
NPDES Inspection Manual 8-13 January 1988
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Chapter Eight
Sampling
LABORATORY QUALITY ASSURANCE CHECKLIST
A. GENERAL
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
1.
1.
2.
3.
4.
5.
6.
Written laboratory QA manual is available.
B. LABORATORY PROCEDURES
EPA-approved analytical testing procedures used and
on-hand, (written)
If alternate analytical procedures used, proper
approval obtained.
Calibration and maintenance of instruments and
equipment satisfactory.
QC procedures used.
QC procedures adequate.
Duplicate samples analyzed % of time.
7. Spiked samples used % of time.
8.
Commercial laboratory used. Name
Address
Contact
Phone
Certification #
C. LABORATORY FACILITIES AND EQUIPMENT
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes NO N/A
Yes No N/A
Yes No N/A
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Proper grade laboratory pure water avail
specific analysis.
Dry, uncontaminated, compressed air avai
Fume hood sufficiently ventilated.
Laboratory sufficiently lighted.
Adequate electrical sources available.
Instruments/equipment in good condition.
Written requirements for daily operation
instruments available.
Standards and appropriate blanks availab
daily check procedures.
Written troubleshooting procedures for i
available.
Schedule for required maintenance exists
Proper volumetric glassware used.
Glassware properly cleaned.
Standard reagents and solvents properly
Working standards frequently checked.
able for
lable.
of
le to perform
nstruments
•
stored.
Standards discarded after recommended shelf-life
has expired.
Background reagents and solvents run with every
series of samples.
NPDES Inspection Manual
January 1988
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Chapter Eight
SamplIng
Yes No N/A
Yes No N/A
D.
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
Yes No N/A
17.
18.
LABORATORY QUALITY ASSURANCE CHECKLIST
(Continued)
Written procedures exist for cleanup, hazard response
methods, and applications of correction methods for
reagents and solvents.
Gas cylinders replaced at 100-200 psi .
LABORATORY'S PRECISION, ACCURACY, AND CONTROL PROCEDURES
1.
2.
3.
4.
1.
2.
3.
4.
5.
6.
Multiple replicates (blanks, duplicates, spikes, and
splits) analyzed for each type of control check and
information recorded.
Plotted precision and accuracy control methods used
to determine whether valid, questionable, or invalid
data are being generated from da^ to day.
Control samples introduced into the train of actual
samples to ensure that valid data are being generated.
Precision and accuracy of the analyses are good.
E. DATA HANDLING AND REPORTING
Round-off rules uniformly applied.
Significant figures established for each analysis.
Provision for cross-checking calculation used.
Correct formulas used to calculate final results.
Control chart approach and statistical calculations
for QC and report available and followed.
Report forms developed to provide complete data
documentation and permanent records and to facilitate
data processing.
7. Data reported in proper form and units.
8. Laboratory records readily available to regulatory
agency for required time 3 years.
9.
10.
1.
2.
3.
Laboratory notebook or pre-printed data forms bound
permanently to provide good documentation.
Efficient filing system exists, enabling prompt
channeling of report copies.
F- LABORATORY PERSONNEL
Enough analysts present to perform the analyses
necessary.
Analysts have on-hand the necessary references for
EPA procedures being used.
Analysts trained in procedures performed through
formal or informal training or certification programs.
NPDES Inspection Manua
8-16
January 1988
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Chapter Nine
PRETREATMENT
Contents Page
A Review of the General Pretreatment Regulations
Development of 40 CFR Part 403 9-1
Approval Authority Responsibilities 9-2
POTW Responsibilities 9-4
Industry Responsibilities 9-6
B Pretreatment Compliance Inspections (PCIs) and Audits
Scope of PCIs and Audits 9-19
PCI Checklist Components 9-21
Summary of Audit Checklist Components 9-23
C References 9-25
List of Tables
9-1 Summary of the General Pretreatment Regulations 9-9
9-2 Summary Status of National Categorical Pretreatment
Standards: Milestone Dates 9-14
NPDES Inspection Manual g^\ January 1988
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Chapter Nine
A REVIEW OF THE GENERAL
PRETREATMENT REGULATIONS
Development of 40 CFR Part 403
The Clean Water Act (CWA) requires EPA to promulgate regulations to
control the discharge of pollutants to the Nation's waters in order to preserve
their physical, chemical, and biological integrity. The National Pollutant
Discharge Elimination System (NPDES) program is the primary regulatory mechanism
developed to control point-source discharges to the surface waters of the United
States. The National Pretreatment Program is the mechanism developed to regulate
industries that discharge pollutants to publicly owned treatment works (POTWs),
which in turn are regulated under the NPDES program.
The General Pretreatment Regulations (40 CFR Part 403) were promulgated on
June 26, 1978. Amendments to the regulations were promulgated on January 28,
1981. These regulations establish the basic pretreatment procedures, respon-
sibilities, and requirements for EPA, States, POTWs, and industries. The defini-
tion for new source was promulgated July 10, 1984. Definitions for interference
and pass through were promulgated on January 14, 1987. On June 12, 1986, EPA
proposed additional changes to Part 403 in response to recommendations made by
the Pretreatment Implementation Review Task Force (PIRT). At the time of
publication of this document, these amendments are being finalized. A summary
of the General Pretreatment Regulations is provided in Table 9-1. Major techni-
cal changes resulting from final regulatory amendments or court decisions are
noted in this table.
The purpose of the General Pretreatment Regulations is to protect POTWs and the
environment from the damage that may result from discharges of pollutants to
sanitary sewer systems. The three specific objectives cited in Part 403.2 of
the General Pretreatment Regulations are to:
• Prevent the introduction of pollutants that would cause interference
with the POTW or limit the use and disposal of its sludge
• Prevent the introduction of pollutants that would pass through the
treatment works or be otherwise incompatible
t Improve the opportunities to recycle or reclaim municipal and industrial
wastewaters and sludges.
NPDES Inspection ManualgTiJanuary 1988
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Chapter Nine Pretreatment
In addition, improved POTW worker health and safety and reduction of influent
loadings to sewage treatment plants are further objectives of pretreatment.
Briefly stated, the definitions for interference and pass through are the
following (see 40 CFR 403.3 for the exact definitions).
o Interference is a discharge that alone or in conjunction with other
discharges, disrupts the POTW or sludge processes, and therefore in turn
causes violation of any requirement of the POTW's NPDES permit or
prevents the POTW from using its chosen sludge use or disposal practice.
o Pass through is a discharge that exits the POTWs to waters of the United
States in quantities or concentrations which, alone or in conjunction
with other discharges, causes a POTW NPOES permit violation.
The General Pretreatment Regulations detail the procedures, responsibilities,
and requirements of EPA, States, POTWs, and industries. To achieve the object-
ives of the regulations, implementation of the program by all regulated
entities must be accomplished. In the next three sections, the specific
responsibilities of each are explained.
Guidance manuals developed to assist EPA Regional Offices, States, POTWs, and
industries with implementation of the General Pretreatment Program are listed
in Section C, "References," of this chapter. In addition, policy memorandums
from the EPA Office of Water Enforcement and Permits on pretreatment issues are
listed.
Approval Authority Responsibili't'ies
Two terms are important in understanding the General Pretreatment Regulations:
"Control Authority" and "Approval Authority." Control Authority directly
regulates the significant industrial users discharging to a POTW; Approval
Authority oversees the development and implementation of POTW pretreatment
programs and, for POTWs without an approved pretreatment program, is also the
Control Authority that regulates industrial discharges to the POTW. The EPA
Regional Office is the Approval Authority until a State is delegated the
authority to administer the pretreatment program.
A pretreatment program is administered through the EPA Regional Office or a
State with NPOES and pretreatment delegation. The principal tasks for which an
Approval Authority (EPA Regional Office or delegated State) is responsible are:
o Review and approval of POTW pretreatment programs.
o Oversight of POTW program implementation: Pretreatment Compliance
Inspections (PCIs), audits, and annual report reviews.
NPOES Inspection Manual 9-2 January 1988
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Chapter Nine Pretreatment
• Providing technical assistance to POTWs in implementation of the
requirements of the General Pretreatment Regulations, categorical
pretreatment standards, and POTW pretreatment program requirements.
• Notifying POTWs of program requirements.
• Applying and enforcing pretreatment standards at industries discharging
to POTWs that do not have an approved local pretreatment program (see
"POTW Responsibilities" for what POTW program development entails).
t Initiating enforcement action against noncompliant POTWs or industries.
Part 403.10 of the General Pretreatment Regulations identifies the requirements
a State must meet to receive delegation of the pretreatment program as part of
its NPDES authority, that is, to become an Approval Authority. All States
having or seeking NPDES authority must apply for pretreatment program delegation.
Part 403.10(f) lists the requirements to be addressed in a State pretreatment
program submission. In summary, the State is required to develop and document
the following:
• Legal authority. A statement from the Attorney General that certifies
that the State has enabling statutes and regulations that provide
adequate authority to allow the operation and enforcement of the pre-
treatment program as specified by the General Pretreatment Regulations
t Procedures. Procedures to implement and enforce the pretreatment
program and Sections 307(b) and (c), and 402(b)(l), (2), (8), and (9)
of the Act
• Resources. The State must ensure adequate funding, equipment, and
personnel for implementing the program as described in the procedural
section of the submission.
For States preferring to assume the responsibility of directly regulating indus-
tries discharging to POTWs and, hence, being considered the Control Authority
in lieu of POTWs within the State, Part 403.10(e) provides that option. The
State then must develop as part of the program additional procedures that
detail how it will implement the Control Authority responsibilities. This
document is submitted to EPA for approval, and upon receipt of approval, the
State will become responsible for the principal Approval Authority implementation
tasks specified above and Control Authority responsibilities for all indirect
industrial dischargers, if the State has developed the additional procedures
for regulating the appropriate industries without POTW pretreatment programs.
NPDES Inspection Manual 9-3 January 1988
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Chapter Nine Pretreatment
POTW Responsibilities
POTW pretreatment program development and implementation requirements must be
included in the NPDES permit of POTWs required to develop programs. Those
requirements will thereby become an enforceable component of the permit. Part
403.8 of the General Pretreatment Regulations details the responsibilities of a
POTW during the development of a pretreatment program. In summary, the POTW
must address the following four tasks:
• Legal authority. The POTW must develop the legal authorities that
will enable it to apply and enforce the General Pretreatment Regu-
lations and local sewer use regulations.
• Technical evaluation.
- Identification of all industrial users that may discharge wastes of a
volume, concentration, or nature of concern to the POTW (significant
industrial users), including all categorical industries
- Determine sampling and analysis needs
- Determine the character and volume of pollutants discharged to the
POTW
- Identify pollutants that may interfere or pass through the treatment
plant or cause sludge contamination
- Determine the maximum allowable pollutant loading to the treatment
plant for all pollutants of concern
- Develop specific limitations for pollutants of concern where needed
to prevent pass through, interference, and sludge contamination.
• Procedures. The POTW must develop administrative procedures to
implement the program including:
- Collecting industrial discharge data through industrial self-
monitoring reports and/or POTW monitoring
- Evaluating industrial user compliance
- Notifying users of pretreatment requirements and other appropriate
regulations
- Updating the industrial user survey
- Administering a permit system or other means to convey pretreatment
standards and requirements
- Initiating appropriate enforcement action.
• Administrative organization. The POTW must provide sufficient
resources (funds, personnel, and equipment) to operate an effective
program and must maintain and manage the data collected during
program development and implementation.
Additional information on the responsibilities of POTWs is provided in the EPA
Guidance Manual for POTW Pretreatment Program Development.
NPDES Inspection Manual
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Chapter Nine Pretreatment
The POTW program is submitted to the Approval Authority, either the EPA
Regional Office or the delegated State. Once approval has been received, the
NPOES permit is amended to require the POTW to implement the program. As of
December 31, 1987, 1,464 POTWs have been required to develop programs; 1,410
of these programs have been approved.
Before a POTW pretreatment program is approved, the Approval Authority is the
Control Authority for industries discharging to the POTW. After program approval,
the POTW becomes responsible for implementing the requirements specified in the
General Pretreatment Regulations [40 CFR Part 403.3(f)], the POTW prebreatment
program, as well as the requirements of the NPDES permit (the permit must be
complied with regardless of program approval). To fully implement the pretreat-
ment program throughout the entire service area, the POTW must do the following:
o Legal authority
- Implement and enforce an adequate sewer use ordinance
- Implement the industrial user control mechanism (e.g., industrial
user permit program)
- Maintain current agreements or contracts with other political
jurisdictions that discharge to the POTW.
o Pretreatment standards
- Identify the character and volume of pollutants contributed to the POTW
- Reevaluate local limits periodically to ensure protection of the POTW
from interference or pass through and bo ensure the use or disposal
of POTW sludge
- Notify all industrial users of appropriate pretreatment standards,
any changes to the regulations, and Resource Conservation and
Recovery Act (RCRA) requirements
- Apply appropriate pretreatment standards to all significant industrial
users (i.e., categorical pretreatment standards or local limits
whichever are more stringent)
- Update the industrial survey to identify new industries that
should be regulated by the POTW pretreatment program, and identify
changes in manufacturing processes and wastewater discharge char-
acteristics at existing facilities
- Comply with public participation requirements.
o Industrial user compliance and enforcement
- Establish reporting, inspection, and monitoring requirements and
procedures to enable evaluation of compliance
- Develop an enforcement management strategy to guide compliance
evaluation and enforcement activities
- Evaluate industry compliance by reviewing and analyzing of self-
monitoring reports and POTW monitoring
- Identify noncompliant industries
- Initiate appropriate enforcement action to bring users into compliance
- Establish other procedures as required and/or determined to be
needed to regulate the significant industries discharging to the
POTW.
NPDES Inspection Manual 9-5 January 1988
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Chapter Nine Pretreatment
• Public participation
- Publish a list, in the local newspaper with the greatest circulation,
of the industrial users that were in significant violation within the
past 12 months as defined in 40 CFR Part 403.8(f)
- Notify the public of any changes to the sewer use ordinance or local
limits after approval by the Approval Authority
- Submit pretreatment program modifications to Approval Authority.
• Data management
- Maintain records of pertinent industrial user activities and compliance
status
- Maintain a current understanding of the categorical pretreatment
standards and General Pretreatment Regulations and notify
industries of any changes
- Provide the Approval Authorities with any reports required.
• Resources
- Provide adequate resources for implementation.
As pretreatment needs change, the POTW may need to revise the approved
program. When this occurs, the POTW should submit the modifications to the
Approval Authority for review and approval.
Industry Responsibilities
Industrial dischargers to POTWs must comply with the following:
• Prohibited discharge standards: The general and specific prohibited
discharge standards (40 CFR Part 403.5) are noted in Table 9-1.
• Appropriate pretreatment standards: Categorical pretreatment standards,
State requirements, or locally developed discharge limitations.
• Reporting requirements: As specified in Part 403.12 and/or by the
POTW. The requirements provided in Part 403.12 are summarized in
Table 9-1.
The types of industrial facilities that are categorical industries are listed
in Table 9-2. EPA has developed categorical pretreatment standards for these
industries based on the characteristic wastes produced by the manufacturing
processes at each type of industry, the wastewater control technologies
available to the industry, and economic considerations. The categorical
pretreatment standards developed apply to the wastewaters from specific
manufacturing processes. The standards apply at the point of discharge from
the pretreatment unit for the regulated process, or if there is no pretreatment
unit, they apply at the point of discharge of the process wastewater.
NPDtS Inspection Manual9^6January 1988
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Chapter Nine Pretreatment
Where the POTW has determined that specific limitations for certain pollutants
of concern are needed to protect the POTW from interference, pass through and
sludge contamination, the POTW must develop and enforce such limitations.
These local limitations generally are applied at the point the industrial
facility discharges to the POTW.
An industry must meet the more stringent pretreatment standard for each pollu-
tant. For a categorical industry, this will be the categorical pretreatment
standard or a local limit for each pollutant regulated. If the point at which
the POTW's limitation applies is not the same as the point at which the cate-
gorical pretreatment standard applies, then a calculation to adjust the cate-
gorical pretreatment standard may have to be used to compare the discharge
limitations.
When evaluating the pretreatment standards to determine the appropriate limita-
tion, note that different categorical pretreatment standards were developed
for each type of industry. If the industry combines the flows from more than one
regulated process or combines a regulated process flow with other flows before
these wastes are treated, the Control Authority and the industry must adjust
the categorical pretreatment standard using the Combined Wastestream Formula
(CWF). The equation is provided in Part 403.6(e) of the General Pretreatment
Regulations. If the wastewaters are mixed after treatment, the categorical
pretreatment standards must still be adjusted, in this case by flow weighted
averaging of all flows introduced prior to the sample point. Additional
information on the combined wastestream formula and the flow weighted averaging
formula is provided in the EPA Guidance Manual for Implementing Production -
Based Pretreatment Standards and the Combined Wastestream Formula (US EPA"
1985).
Table 9-2 summarizes the important milestone dates for categorical industries:
the publication dates of the proposed and final regulations, the effective and
compliance dates, and the due dates for reports specified in the General Pre-
treatment Regulations. The appropriate regulation should be referenced to
determine the applicable categorical pretreatment standards.
Categorical industries have specific reporting requirements as per Part 403.12.
A summary of the reports that categorical industries are required to submit is
provided in Table 9-1. A POTW may require additional reports from all industries
discharging to the system, including categorical industries.
NPDES Inspection Manual 9-7 January 1988
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Chapter Nine Pretreatment
Table 9-1
Summary of the General Pretreatment Regulations
403.1 Purpose and Applicability
403.2 Objectives of General Pretreatment Regulations
403.3 Definitions
403.4 State or Local Law
The Federal General Pretreatment Regulations are not meant to
affect any state or local regulatory requirements as long as
these requirements are at least as stringent as the Federal
regulations.
403.5 National Pretreatment Standards: Prohibited Discharges
This section specifies general and specific prohibited
discharge standards that POTWs must incorporate into their
local limits. The general prohibitions specify that
pollutants introduced into POTWs by a nondomestic source shall
not pass through the POTW or interfere with the operation or
performance of the works. The section provides that POTWs
that are required to develop local pretreatment programs (and
POTWs where interference and pass through are likely to re-
occur) develop and enforce specific limitations (local limits)
to implement the general prohibitions against interference,
pass through and sludge contamination.
The specific prohibitions specify prevention of discharge
of pollutants that cause any of the following at the POTW:
o Fire or explosion hazard
o Corrosive structural damage - no pH<5.0
o Obstruction to the flow in the POTW
o Interference
o Heat causing inhibition of biological activity and
temperatures at the POTW treatment plant to exceed
40°C (104°F)
NPDES Inspection Manual 9-9 January 1988
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Chapter Nine Pretreatment
Table 9-1
Summary of the General Pretreatment Regulations (Continued)
403.6 National Pretreatment Standards: Categorical Standards
This section discusses development and implementation of
Categorical Pretreatment Standards including, but not limited
to, compliance deadlines, prohibition of dilution as a sub-
stitute treatment, and the combined wastestream formula
(CWF) to determine discharge limitations.
403.7 Revision of Categorical Pretreatment Standards to Reflect POTW
Removal of Pollutants
This section (referred to as the removal credits provision)
provides the criteria and procedures to be used by a POTW in
revising the pollutant discharge limits specified in Cate-
gorical Pretreatment Standards to reflect removal of pollutants
by the POTW. (No removal credits may be granted until the
final sludge regulations are promulgated.)
403.8 POTW Pretreatment Programs: Development by POTW
This section covers the requirements for pretreatment program
development by a POTW. Included in this section are criteria
for determining which POTWs must develop pretreatment programs,
incorporation of approved programs and compliance schedules
into NPDES permits, deadlines for program approvals, and
program funding requirements. The section requires the POTW to
have legal authority to enforce the approved pretreatment
program. The section also discusses that all POTWs with
approved programs, or programs under development, must develop
and implement procedures to ensure compliance with the
requirements of a pretreatment program.
403.9 POTW Pretreatment Programs and/or Authorization to Revise
Pretreatment Standards: Submission for Approval
This section discusses requirements and procedures for sub-
mission and review of POTW pretreatment programs. Included
in this section are discussions of conditional program
approval, approval authority action, and notification where
submissions are defective.
NPDES Inspection Manual ^TD January 1988
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Chapter Nine Pretreatment
Table 9-1
Summary of the General Pretreatment Regulations (Continued)
403.10 Development and Submission of NPDES State Pretreatment Programs
This section discusses requirements and procedures for submis-
sion and review of NPDES state pretreatment programs. Included
in this section are discussions of approvals and deadlines for
state programs, program and funding requirements, and contents
of program submissions.
403.11 Approval Procedures for POTW Pretreatment Programs and POTW
Revision of Categorical Pretreatment Standards
This section provides the administrative procedures for the
review and approval or denial of POTW pretreatment program
submissions and requests for removal credit authority.
403.12 Reporting Requirements for POTWs and Industrial Users
This section presents reporting requirements for POTWs and
industrial users. Reports required by industrial users
include the following:
• Baseline monitoring report (BMR). Due to the Control
Authority within 180 days of the effective date of
the categorical pretreatment standards (40 CFR Part 403.6).
In addition, new source BMR reporting requirements are
discussed in this section.
t Compliance schedule progress reports. Due to the Control
Authority within 14 days of completion of compliance
schedule milestones or due dates.
• 90-day compliance report. Due to the Control Authority
within 90 days of the compliance date of the categorical
standards.
• Periodic compliance reports. Due to the Control Authority
at least semi-annually, usually in June and December after
the compliance date.
• Notices of slug loadings. Due to the POTW immediately upon
identification of the slug discharge for both noncategorical
industries as well as categorical.
NPDES Inspection Manual
-------
Chapter Nine Pretreatnent
Table 9-1
Summary of the General Pretreatment Regulations (Continued)
403.12 (Continued)
Reports required from POTWs include the following:
• Compliance schedule (for development of pretreatment pro-
grams) progress reports
• Removal credit "reports.
Also discussed in detail in this section are monitoring require-
ments for industrial users and signatory and recordkeeping
requirements for POTWs and industrial users.
403.13 Variances from Categorical Pretreatment Standards for
Fundamentally Different Factors
This provision allows an industrial user, or any interested
person, to request a variance for the establishment of limits
either more or less stringent than that required by a Categor-
ical Pretreatment Standard. The primary criterion required for
approval of this variance is that the factors relating to the
industrial user's discharges are fundamentally different from
factors considered by EPA in establishing Categorical
Pretreatment Standards for these discharges.
403.14 Confidentiality
This section covers confidentiality requirements and prohibi-
tions for EPA, states, and POTWs. Effluent data is available
to the public without restriction.
403.15 Net/Gross Calculation
This provision provides for adjustment of Categorical Pretreat-
ment Standards to reflect the presence of pollutants in the
industrial user's intake water.
403.16 Upset Provision
This provision is consistent with the NPDES regulations and
allows an upset of an industry's pretreatment system (which
meets the conditions of an upset as specified in this pro-
vision) to be an affirmative defense to an action brought for
noncompliance with Categorical Pretreatment Standards. The
industrial user shall have the burden of proof for such a
defense.
NPDES Inspection Manual97T2January 1988
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Chapter Nine Pretreatment
Table 9-1
Summary of the General Pretreatment Regulations (Continued)
Appendix A Program Guidance Memorandum
This memorandum summarizes the Agency's policy on the use of
construction grants for treatment and control of combined sewer
overflows and stormwater discharges.
Appendix B 65 Toxic Pollutants
This appendix lists the 65 classes of toxic pollutants that are
regulated by the pretreatment program through Categorical
Pretreatment Standards
Appendix C 34 Industrial Categories (Amended and retitled as "Indus-
trial Categories Subject to National Categorical Pretreatment
Standards")
This appendix lists industrial categories (except those that
are exempted by paragraph 8 of the NRDC V. EPA Consent Decree)
that are under consideration to be regulated by Categorical
Pretreatment Standards. Standards have been promulgated or
proposed for 24 categories.
Appendix D Selected Industrial Subcategories Exempted from Regulation
Pursuant to Paragraph 8 of the NRDC v. Costle Consent Decree
(Amended and retitled as "Selected Industrial Subcategories
Considered Dilute for Purposes of the Combined Wastestream
Formula")
Appendix D is to be used only for the purpose of applying the
combined wastestream formula. Wastestreams for the Subcate-
gories listed in the appendix are "dilute" wastestreams as per
the definition in the formula.
NPDES Inspection Manual9:T1January 1988
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Table 9-2
Summary Status of National Categorical Pretreatment Standards:
Milestone Dates
40 CFR
Industry Category Part
Aluminum Forming
Battery Manufacturing
Coil Coating I
Coil Coating (Canmaking)
Copper Forming
Electrical & Electronic
Components I
Electrical & Electronic
Components II
Electroplating
Inorganic Chemicals
Interim, I & II
Iron & Steel
Leather Tanning &
Finishing
467
461
465
465
468
469
469
413
415
420
425
Proposed/
New Source
Rule Date(2)
11-22-82
11-10-82
1-12-81
2-10-83
11-12-82
8-24-82
3-09-83
7-30-80(4)
—
7-24-80
10-25-83
1-07-81
7-02-79
Final
Final Rule
Date
10-24-83
3-09-84
12-01-82
11-17-83
8-15-83
4-08-83
12-14-83
1-28-81
7-15-83
7-20-77
6-29-82
8-22-84
5-27-82
11-23-82
Regulations(l)
Effective
Date
12-07-83
4-23-84
1-17-83
1-02-84
9-26-83
5-19-83
1-27-84
3-30-81
8-29-83
7-20-77
8-12-82
10-05-84
7-10-82
1-06-83
BMR
Due Date
6-04-84
10-20-84
7-16-83
6-30-84
3-25-84
11-15-83
7-15-84
9-26-81
(Non-int.)
6-25-83
(Int.)
2-25-84
(TTO)
1-16-78
5-09-83
4-03-85
4-06-83
7-05-83
90-day
PSES Compliance
Compliance Report
Date Due Date
10-24-86
3-09-87
12-01-85
11-17-86
8-15-86
7-01-84 (TTO)(3)
11-08-85 (As)
7-14-86
4-27-84
(Non-int.)
6-30-84
(Int.)
7-15-86
(TTO)
See Footnote(5)
7-10-85
11-25-85
1-22-87
6-07-87
3-01-86
2-15-87
11-13-86
9-29-84
2-06-86
10-12-86
7-26-84
9-28-84
10-13-86
10-18-80
9-27-85
11-20-87
10-08-85
2-23-86
o
3-
Ol
•u
rt
n>
-------
Table 9-2
Summary Status of National Categorical Pretreatment Standards: Milestone Dates (Continued)
Final Regulations
Industry Category
Metal Finishing
Metal Molding and
Casting (Foundries)
Nonferrous Metals
Forming
Nonferrous Metals I
Nonferrous Metals II
Organic Chemicals,
Plastics and
Synthetic Fibers
(OCPSF)
Pesticide Chemicals
Petroleum Refining
Pharmaceuticals
Manufacturing
Porcelain Enameling
40 CFR
Part
433
464
471
421
421
414
416
455
419
439
466
Proposed/
New Source
Rule Date(2)
8-31-82(4)
11-15-82
3-05-84
2-17-33
6-27-84
3-21-83
11-30-82
12-21-79
11-26-82
2-27-81
Final Rule
Date
7-15-83
10-30-85
8-23-85
3-08-84
9-20-85
11-05-87
10-04-85
10-18-82
10-27-83
11-24-82
Effective
Date
8-29-83
12-13-85
10-07-35
4-23-84
11-04-85
12-21-37
(Remanded 7/86
12-01-82
12-12-83
1-07-83
BMR
Due Date
2-25-84
6-11-86
4-05-86
10-20-84
5-03-36
6-20-88
. Removed
5-30-83
6-09-84
7-06-83
PSES
Compliance
Date
6-30-84 (Part 433,
TTO)(6)
7-10-85 (Part 420,
TTO)
2-15-86 (Final)
10-31-88
8-23-88
3-09-87
9-20-88
11-05-90
12/86. See footnote (7))
12-01-85
10-27-86
11-25-85
90-day
Compliance
Report
Due Date
9-23-84
10-08-85
5-16-86
1-29-39
11-21-83
6-07-87
12-19-88
2-03-91
3-01-85
1-25-87
2-23-86
-------
Table 9-2
Summary Status of National Categorical Pretreatment Standards: Milestone Dates (Continued)
Industry Category
Pulp, Paper,
Paperboard
Steam Electric Power
Generation
Timber Products
Processing
40 CFR
Part
430
431
423
429
Proposed/
New Source
Rule Date(2)
1-06-81
10-14-80
10-31-79
Fina
Final Rule
Date
11-18-82
11-19-82
1-26-81
1 Regulations
Effective
Date
1-03-83
1-02-83
3-30-81
BMR
Due Date
7-02-83
7-01-83
9-26-81
PSES
Compli ance
Date
7-01-84
7-01-84
1-26-84
90-day
Compli ance
Report
Due Date
9-29-84
9-29-84
4-25-84
-------
Chapter Nine Pretreatment
Table 9-2
Summary Status of National Categorical Pretreatment Standards:
Milestone Dates (Continued)
Footnotes:
(1) The dates identified below are for all categorical standards that have
been finalized. Other categories, or modifications to existing categories may be
proposed in the future. These changes will be incorporated in future editions of
this manual.
(2) The date of the proposed rule is used to determine sources regulated
by categorical pretreatment standards for new sources. Industrial facilities
that were in existence, or began construction of the regulated processes before
that date, are considered existing sources and are regulated by categorical
Pretreatment Standards for Existing Sources (PSES). New sources are facilities
that began construction of the regulated processes after the date of the
proposed rule. The compliance date for any new source (PSNS) is the same date
as the commencement of the discharge.
(3) The compliance date for existing phase I electrical and electronic
components manufacturers for total toxic organics (TTO) is July 1, 1984. The
compliance date for arsenic is November 8, 1985.
(4) The electroplating proposed rule date is not used to determine new
source/existing source. The metal finishing proposed rule date is used for
all electroplating and metal finishing facilities.
(5) The compliance date for Subparts A, B, L, AL, AR, BA, and BC is July 20,
1980. The compliance date for Subparts AJ, AD, Bl_, BM, BN, and BO (except dis-
charges from copper sulfate or nickel sulfate processes) is August 22, 1987.
The compliance date for copper sulfate or nickel sulfate processes and for all
Subparts of Part 415 not listed above is June 29, 1985. Reference: Part 415.01,
Compliance Dates for Pretreatment Standards for Existing Sources, Federal Register,
Vol. 49, page 43420, August 22, 1984.
(6) Existing sources that are subject to the metal finishing standard in
40 CFR Part 433 must comply only with the interim limit for TTO by June 30, 1984,
except for facilities that are also subject to the iron and steel manufacturing
standards in 40 CFR Part 420, which must comply with the interim TTO limit by
July 10, 1985. The compliance date for metals, cyanide, and final TTO is
February 15, 1986, for all sources.
(7) On July 25, 1986 the Eleventh Circuit Court of Appeals remanded to
EPA the final regulation for the Pesticide Chemicals Category Effluent Limitations
Guidelines, Pretreatment Standards, and New Source Performance Standards. EPA
removed the regulation from the Code of Federal Regulations on December 15,
1986 (51 FR 44911).
NPDES Inspection Manual 9-17 January 1988
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Chapter Nine
B PRETREATMENT COMPLIANCE
INSPECTIONS (PCIs) AND AUDITS
Scope of PCIs and Audits
The Pretreatment Compliance Inspection (PCI) and audit have been developed
as oversight mechanisms for Approval Authorities. They provide an opportunity
for EPA and State officials to conduct an on-site review of a POTW pretreat-
ment program.
The PCI has been designed to be incorporated into the existing NPDES inspec-
tion program. The focus is to evaluate POTW compliance monitoring and
enforcement activities. The PCI also is designed to determine if any changes
have been made to the POTW program since the last PCI, audit, annual report,
or POTW program modification request approval. The role of a NPDES inspector
during a PCI is as a data gatherer to collect information on POTW program
implementation for further evaluation by Water Enforcement and Permits personnel
The PCI should be conducted in conjunction with other NPDES inspections to
conserve travel resources and allow integration of information on the many
facets of a POTW's operations. PCIs are compatible with Compliance Evaluation
Inspections (CEIs), Compliance Sampling Inspections (CSIs), Performance Audit
Inspections (PAIs), Diagnostic Inspections (DIs), and other nonroutine
inspections, such as Toxics Sampling Inspections, and Compliance Biomonitoring
Inspections.
It should be noted that the POTW personnel involved in a CSI may be different
from the ones involved in a PCI. Also PCIs and audits rely heavily on file and
record reviews to evaluate the POTW's pretreatment program implementation
efforts. These records may have little bearing on a technical inspection of
the treatment facility. This aspect of a PCI should be addressed when planning
for the inspection.
Audits have been designed as a comprehensive review of all facets of the POTW
pretreatment program. The audit addresses all of the items covered in a PCI,
sometimes in more detail, as well as seeks additional information about other
implementation tasks, such as: legal authority, application of pretreatment
standards, data management, and program resources. The audit is more resource
intensive than the PCI.
NPDES Inspection Manual 9-19 January 1988
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Chapter Nine Pretreatment
A May 13, 1986, memorandum from James Elder, Director, Office of Water Enforce-
ment and Permits, stated the strategy for conducting PCIs and audits. Audits
would be conducted every fifth year, preferably during the year of NPDES permit
reissuance so that any additional requirements for program implementation could be
incorporated in the reissued permit. PCIs would be conducted during intervening
years.
Procedures for conducting PCIs and audits are similar. In general, there are
three major components:
t Pre-visit preparation for the PCI or audit
- Coordination with the EPA Regional or State Pretreatment Coordinator
- Review of background information: approved program, POTW annual
reports (if available), NPDES permit compliance status, POTW
fact sheet, and program modification requests from the POTW
- Notification of POTW officials (if appropriate).
0 On-site
- Opening conference with POTW officials
- Interview of officials using PCI or audit checklist
- Review of POTW pretreatment files
- Industrial inspections (optional)
- Tour of POTW (optional)
- Closing conference.
• Follow-up
- Preparation of report
- Data entry into PCS
- Follow-up letter to the POTW
- Enforcement action (when necessary)
- NPDES permit or program modifications (when necessary).
If a PCI is conducted with an unannounced NPDES inspection, it also may be
unannounced, but the POTW officials should be notified of the PCI upon arrival
of the inspection team. At many POTWs, personnel responsible for implementing
the program may not be the same as those operating the treatment plant.
The protocol involved in the on-site portion of the inspection is comparable to
that of other NPDES inspections. One aspect of a POTW PCI or audit that differs
from other NPDES compliance inspections is inclusion of a tour of industrial
facilities discharging to the POTW. This aspect may be included as an optional
component of both PCIs and audits to evaluate the POTW's procedures for monitoring
and inspecting industries. For more detailed information on conducting PCIs
and audits, a guidance manual has been developed by the Office of Water Enforce-
ment and Permits: Pretreatment Compliance Inspection and Audit Manual for
Approval Authorities (USEPA 1986b).
NPDES Inspection Manual 9-20 January 1988
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Chapter Nine Pretreatment
A detailed checklist intended for use during a PCI is provided in the PCI and
audit guidance manual. The organization and focus of the detailed checklist
are discussed in the following section.
PCI Checklist Components
The PCI checklist was developed to assist NPDES inspectors in conducting and
documenting the PCI. The checklist is organized into four sections:
• Control Authority Background Information
• Compliance Monitoring and Enforcement--POTW Personnel Response
• Compliance Monitoring and Enforcement--POTW File Evaluation
t Summary Evaluation of POTW Pretreatment Program.
The first section should be completed before the on-site visit from a file
review and/or a POTW program fact sheet that has been developed. This infor-
mation should be verified during the POTW personnel interview. The second and
third sections are conducted on-site, one as an interview with the POTW personnel
and the other from information collected during a review of the POTW's files
on industrial users. The final section is completed after the on-site portion
of the PCI as an evaluation of the information collected.
In more detail, the four sections address the following information:
Section I: Control Authority Background Information
This section summarizes information about the Control Authority, including
NPDES permit number, previous PCIs or audits, annual reports, and current
POTW official responsible for the pretreatment program. The importance of
reviewing previous PCIs or audit reports and discussing the POTW program
with the Regional and/or State Pretreatment Coordinator and compliance
personnel cannot be overemphasized. This preparation can help focus the
PCI inspector on the problems of the POTW pretreatment program and increase
the effectiveness of the program.
Section II: Compliance Monitoring and Enforcement—Control Authority
Personnel Response
This section is divided into six parts, each addressing a different aspect
of the POTW's application of pretreatment standards, compliance evaluation,
and enforcement activity. The information is collected by interviewing the
appropriate POTW personnel. The following topics should be discussed:
• Control Authority Pretreatment Program Overview. This section
requests details about the POTW program: number of industries
regulated, definition of significant industrial users, percentage
of industrial flow to the POTW, and history of problems at the POTW.
• Control Authority Pretreatment Program Modifications. This section
documents any changes to the program since the last PCI or audit,
annual report, or POTW program modification request.
NPDES Inspection Manual 9^1 January 1988
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Chapter Nine Pretreatment
• Control Authority Inspection and Monitoring of Industrial Users.
This section documents the POTW's efforts over the past year in
monitoring and inspecting the regulated industrial users. Questions
are focused on comparing the present effort with the level specified
in the approved POTW program or recommended in EPA guidance docu-
ments such as the Pretreatment Compliance Monitoring and Enforce-
ment Guidance Manual (USEPA 1986c).The type of information
collected by the POTW during industrial inspections or from industrial
self-monitoring reports also is reviewed. The inspector should
also review and attempt to evaluate the POTW's procedures for
monitoring and inspecting industrial facilities.
• Control Mechanism Evaluation. This section documents the status of
control mechanism issuance (i.e., industrial user permits), in
particular the existence of industries that are unregulated or are
operating with an expired control mechanism.
• Enforcement Procedures. This section evaluates the Control Authority
procedures for reviewing industrial user self-monitoring reports
and POTW compliance monitoring data, for evaluating compliance, and
for initiating enforcement action.
t Compliance Tracking. This section determines if the POTW has
developed a tracking system to document regularly the compliance
status of the industrial users.
Section III: Compliance Monitoring and Enforcement—Industrial User
File Evaluation
The PCI reviews the POTW's files as a means of verifying information collected
during the interview. In general, the file is reviewed to determine if
specific items, such as permit applications, permits, industrial inspection
reports correspondence, and monitoring data are retained by the POTW.
The checklist has space for comments on five industrial files; however,
more may be reviewed. The files reviewed during the PCI should be repre-
sentative of the industries regulated by the POTW. Files for categorical
and noncategorical industries and most importantly the files of industries
with compliance problems should be reviewed.
Section IV: Summary Evaluation of Control Authority Pretreatment Program
The summary evaluation provides a mechanism for the inspector to document
the findings of the PCI. This section addresses each of the following
program components individually: Control Authority Monitoring and
Inspection, Industrial User Self-Monitoring, Control Mechanism Issuance,
and Control Authority Enforcement. It also provides an opportunity to
note other findings and follow-up actions that may be necessary. The
inspector should be cautious and not make judgments concerning program
implementation on-site.
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Chapter Nine Pretreatment
Information in the evaluation section can be used as part of the follow-up
response to the POTW. However, before any evaluation of the POTW program
is transmitted to the POTW, the evaluation should be reviewed by Approval
Authority personnel who are fully aware of the pretreatment program require-
ments. In some situations when more formal enforcement action may be
contemplated as a result of the PCI findings, the Approval Authority may
choose not to send the summary evaluation to the POTW.
In addition to the completed checklist, other materials collected during the
PCI may be included in the final report as appendices. These items may include:
Example of POTW enforcement actions
Description of significant changes to the POTW program
Names of industries that were not sampled or inspected in the past year
Names of significant industrial users that are not in compliance
POTW enforcement procedures
Annual list of industrial users with significant violations.
The PCI checklist can be found in the Pretreatment Compliance Inspection and
Audit Manual for Approval Authorities (USEPA 1986b).The manual goes through
each checklist section individually and explains the intent of the questions.
As noted earlier, the manual provides more detailed information concerning the
procedures for conducting the PCI.
Summary of Audit Checklist Components
The audit checklist has been developed to assist with a detailed review of a
POTW pretreatment program. The checklist is more detailed than the one used
for PCIs, since a greater number of POTW pretreatment program components are
reviewed. The audit checklist is divided into the following ten sections, each
of which focuses on a specific program component:
I. Control Authority Background Information
II. POTW Program Fact Sheet
III. Legal Authority and Control Mechanism
IV. Application of Pretreatment Standards
V. Compliance Monitoring
VI. Enforcement
VII. Data Management and Public Participation
VIII. Program Resources
IX. POTW File Review
X. Evaluation and Summary
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Chapter Nine Pretreatment
As with the PCI, the audit is conducted in three stages. The checklist has been
developed to correspond to these stages: pre-visit preparation (Sections I-II)5
POTW interview and file review (Sections III-IX), and evaluation (Section X).
The sections of the audit checklist have been developed to collect more detailed
information than the PCI checklist and, as with the completed PCI checklist,
also may be augmented by additional audit data such as:
• NPDES pretreatment permit conditions
• POTW enforcement documents with pretreatment requirements
(i.e., administrative order, consent decree)
• Locally developed discharge limitations as included in the approved
program (or any limits that have been changed by the POTW)
• Copy of sewer use ordinance if different than in the approved program
• POTW sampling and inspection schedule for regulated industries
• List of industries not sampled or inspected in the past year
• POTW chain-of-custody form
• List of noncompliant industries and history of enforcement actions
taken.
The audit checklist is incorporated as part of the Pretreatment Compliance
Inspection and Audit Manual for Approval Authorities (USEPA 1986b).The manual
provides specific guidance on conducting an audit and using the checklist.
NPDES Inspection Manual 9-24 January 1988
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Chapter Nine
C REFERENCES
The publications and memos listed below are available from USEPA Office of
Water Enforcement and Permits or the Pretreatment Coordinator in your Region.
They are not available from the National Technical Information Service (NTIS).
A checklist for conducting pretreatment compliance inspections and audits is
provided in the Pretreatment Compliance Inspection and Audit Manual for Approval
Authorities (USEPA 1986b).The checklist provides a list of questions that
should be considered during an audit or PCI, and is available from EPA Regional
offices. The Regional or State Pretreatment Coordinator should be contacted
before a PCI or an audit is done.
References
Elder, J.R. May 13, 1986. "Pretreatment Compliance Inspections and Audits."
Office of Water Enforcement and Permits. U.S. Environmental Protection Agency,
Washington, D.C.
Hanmer, R.W. November 5, 1984. "Guidance to POTWs for Enforcement of
Categorical Standards." Office of Water Enforcement and Permits. U.S.
Environmental Protection Agency, Washington, D.C.
Hanmer, R.W. August 5, 1985. "Local Limits Requirements for POTW Pretreatment
Programs." Office of Water Enforcement and Permits. U.S. Environmental Protection
Agency, Washington, D.C.
U.S. Environmental Protection Agency. October 1983. Guidance Manual for POTW
Pretreatment Program Development.
U.S. Environmental Protection Agency. October 1983. Procedures Manual for
Reviewing a POTW Pretreatment Program Submission.
U.S. Environmental Protection Agency. February 1984. Guidance Manual for
Electroplating and Metal Finishing Pretreatment Standards.
U.S. Environmental Protection Agency. July 1984. Guidance Manual for Pulp,
Paper and Paperboard and Builder's Paper and Board Mills Pretreatment Standards.
NPDES Inspection Manual
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January 1988
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Chapter Nine Pretreatment
U.S. Environmental Protection Agency. January 1985. Pretreatment Implementation
Review Task Force (PIRT) Final Report.
U.S. Environmental Protection Agency- September 1985. Guidance Manual for
Implementing Production-Based Pretreatment Standards and the Combined
fastest ream Formula.
U.S. Environmental Protection Agency. September 1985. Guidance Manual for
Implementing Total Toxic Organics (TTO) Pretreatment Standards.
U.S. Environmental Protection Agency. September 1985. Guidance Manual for
Iron and Steel Pretreatment Standards.
U.S. Environmental Protection Agency. September 1985. Guidance Manual
Preparation and Review of Removal Credits Applications.
U.S. Environmental Protection Agency. September 1985. RCRA Information on
Hazardous Wastes for Publicly Owned Treatment Works.
U.S. Environmental Protection Agency. July 1986. Pretreatment Compliance
Inspection and Audit Manual for Approval Authorities.
U.S. Environmental Protection Agency. July 1986. Pretreatment Compliance
Monitoring and Enforcement Guidance Manual.
U.S. Environmental Protection Agency. September 1986. Guidance Manual for
Leather Tanning and Finishing Pretreatment Standards.
U.S. Environmental Protection Agency. September 1986. PRELIM: The EPA Computer
Program/Model for Development of Local Limits, User's Guide, Version 3.0.
Computer diskette for use on an IBM compatible microcomputer also available.
U.S. Environmental Protection Agency. June 1987. Guidance Manual for the
Identification of Hazardous Wastes Delivered to Publicly Owned Treatment Works
by Truck, Rail, or Dedicated Pipe.
U.S. Environmental Protection Agency. August 1987. Guidance Manual for Battery
Manufacturing Pretreatment Standards.
U.S. Environmental Protection Agency. September 1987. Guidance Manual for
Preventing Interference at POTWs.
U.S. Environmental Protection Agency. September 1987. Guidance for Reporting
and Evaluating POTW Noncompliance with Pretreatment Implementation Requirements.
Tj-U.S. GO V E R \MENT PRINTING OFFICE! 1988-516-002/80122
NPOES Inspection Manual 9-26 January 1988
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