EPA-340/1-89-001
HOSPITAL WASTE INCINERATOR FIELD INSPECTION
AND SOURCE EVALUATION MANUAL
Prepared by:
Midwest Research Institute
Suite 350
401 Harrison Oaks Boulevard
Gary, North Carolina 27513
Contract No. 68-02-4463
Work Assignment No. 6
Prepared for:
James Topsale, Region III
Pam Saunders, Headquarters
U. S. Environmental Protection Agency
Stationary Source Compliance Division
Office of A1r Quality Planning and Standards
Washington, O.C. 20460
February 1989
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DISCLAIMER
This manual was prepared by Midwest Research Institute for the
Stationary Source Compliance Division of the U. S. Environmental
Protection Agency. It has been completed in accordance with EPA Contract
No. 68-02-4463, Work Assignment 6. It has been reviewed by the Stationary
Source Compliance Division of the Office of A1r Quality Planning and
Standards, U. S. Environmental Protection Agency and approved for
publication. Approval does not sicjnlfy that the contents necessarily
reflect the views and policies of the U. S. Environmental Protection
Agency. Any mention of product names does not constitute endorsement by
the U. S. Environmental Protection Agency.
The safety precautions set forth in this manual and presented at any
training or orientation session, seminar, or other presentation using this
manual are general in nature. The precise safety precautions required for
any given situation depend upon and must be tailored to the specific
circumstances. Midwest Research Institute expressly disclaims any
liability for any personal injuries, death, property damage, or economic
loss arising from any actions taken in reliance upon this manual or any
training or orientation session, seminar, or other presentations based
upon this manual.
ii
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ACKNOWLEDGEMENT
A primary source of Information for this manual Is the Municipal
Waste Incinerator Field Inspection Notebook prepared by Richards
Engineering, Durham, North Carolina. Much of this document, especially
Chapter 6 "Baseline Inspection Procedures for Hospital Incinerators," has
been drawn extensively from the Richard's document.
The authors acknowledge the guidance and contributions provided by
the EPA work assignment managers, James Topsale, Region III and Pam
Saunders, Stationary Source Compliance Division.
Additionally, the authors acknowledge the contributions of the
following individuals who provided useful comments on the initial draft of
this document: Christopher A. James, EPA/Region X; Jim Eddinger,
EPA/OAQPS; David Painter, EPA/OAQPS; Justine Push, EPA/OECM; Gary Gross,
EPA/Region III; Roger Pfaff, EPA/Reg1on IV; Jay M. Willenberg, State of
Washington, Department of Ecology; Wallace E. Sonntag, New York State,
Department of Environmental Conservation; Carl York, State of Maryland,
A1r Management Administration; and Frank Cross, Cross/Tessitore and
Associates.
111
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TABLE OF CONTENTS
Page
CHAPTER 1.0 INTRODUCTION 1-1
1.1 BACKGROUND 1-1
1.2 PURPOSE 1-1
1.3 SCOPE 1-1
1.4 ORGANIZATION..... 1-2
1.5 REFERENCES FOR CHAPTER 1 1-3
CHAPTER 2.0 GENERAL INSPECTION CONSIDERATIONS 2-1
2.1 LEGAL AUTHORITY OF THE INSPECTOR 2-1
2.1.1 Scope 2-1
2.1.2 State Authority 2-1
2.1.3 Authorized Representatives 2-1
2.1.4 Offslte Inspections 2-2
2.2 REGULATIONS UNDER THE CLEAN AIR ACT 2-2
2.2.1 Existing Regulations 2-2
2.2.2 Possible Future Regulations 2-6
2.3 INSPECTOR RESPONSIBILITIES AND LIABILITIES 2-7
2.3.1 Legal Responsibilities 2-7
2.3.2 Procedural Responsibilities 2-8
2.3.3 Safety Responsibilities 2-9
2.3.4 Professional and Ethical
Responsibi 1 ities 2-9
2.3.5 Quality Assurance Responsibilities........ 2-11
2.3.6 Potential Liabilities 2-11
2.4 GENERAL INSPECTION PROCEDURES 2-12
2.4.1 Preinspection Preparation 2-12
2.4.2 Preentry Observations 2-15
2.4.3 Entry 2-16
2.4.4 Contents and Timing 2-20
2.5 REFERENCES FOR CHAPTER 2 2-25
iv
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TABLE OF CONTENTS (continued)
Page
CHAPTER 3.0 INSPECTION SAFETY 3-1
3.1 SCOPE 3-1
3.2 SAFETY GUIDELINES 3-1
3.3 EQUIPMENT-SPECIFIC SAFETY CONSIDERATIONS 3-5
3.3.1 Incinerators 3-5
3.3.2 Wet Scrubbers 3-6
3.3.3 Dry Scrubbers 3-7
3.3.4 Fabric Filters 3-8
CHAPTER 4.0 VISIBLE EMISSION OBSERVATION 4-1
4.1 EPA REFERENCE METHOD 9 4-1
4.2 CONTINUOUS EMISSION MONITORING FOR OPACITY 4-2
4.3 SPECIAL CONSIDERATIONS FOR OPACITY
OBSERVATIONS AT HOSPITAL INCINERATORS 4-9
4.3.1 Tall Stack/Slant Angle 4-9
4.3.2 Steam (Condensing Water Vapor) Plumes 4-9
4.3.3 Evaluating Visible Emissions 4-9
4.3.4 Fugitive Emissions 4-10
4.4 REFERENCES FOR CHAPTER 4 4-10
CHAPTER 5.0 HOSPITAL INCINERATION SYSTEMS 5-1
5.1 INTRODUCTION 5-1
5.2 TYPES OF HOSPITAL INCINERATOR SYSTEMS 5-1
5.2.1 Principles of Air Supply 5-3
5.2.2 Hospital Incinerator Descriptions 5-9
5.3 AIR POLLUTION CONTROL SYSTEMS 5-22
5.3.1 Wet Scrubbers 5-22
5.3.2 Dry Scrubbers 5-30
5.3.3 Fabric Filters 5-39
5.3.4 Electrostatic Precipitators 5-45
5.4 REFERENCES FOR CHAPTER 5 5-45
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TABLE OF CONTENTS (continued)
CHAPTER 6.0 BASELINE INSPECTION PROCEDURES FOR HOSPITAL
INCINERATORS
6.1
6.2
6.3
6.4
6.5
BASELINE INSPECTION TECHNIQUE
6.1.1 Basic Principles
6.1.2 Counterflow Technique
6.1.3 Co-current Technique
LEVELS OF INSPECTION
6.2.1 Level 4 Inspections
6.2.2 Level 3 Inspections
6.2.3 Level 2 Inspections
6.2.4 Level 1 Inspections
COMMON INSPECTION ACTIVITIES
6.3.1 Prepare a System Flowchart
6.3.2 Identify Potential Safety Problems
6.3.3 Evaluate Locations for Measurement Ports..
6.3.4 Evaluate Visible Emissions
6.3.5 Evaluate Double-Pass Transmlssometer
Physical Condition
6.3.6 Evaluate Double-Pass Transmlssometer
Data
6.3.7 Sulfur Dioxide, Nitrogen Oxides, and
Hydrogen Chloride Monitor Physical
Conditions
6.3.8 Sulfur Dioxide, Nitrogen Oxides, and
Hydrogen Chloride Emission Data
CHARACTERIZATION OF WASTE
6.4.1 Waste Characteristics That Affect
Incinerator Operation
6.4.2 Handling of Infectious Wastes
6.4.3 Waste Inspection
EVALUATION OF COMBUSTION EQUIPMENT
6.5.1 Part icu late Matter and Par ticu late
Metals
6.5.2 Acid Gases
6.5.3 Organics
6.5.4 Infectious Agents
6.5.5 Inspection of Combustion Equipment
6-1
6-1
6-2
6-4
6-4
6-7
6-7
6-9
6-9
6-10
6-10
6-11
6-11
6-12
6-12
6-13
6-13
6-14
6-14
6-15
6-20
6-22
6-23
6-28
6-28
6-29
6-30
6-30
6-31
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TABLE OF CONTENTS (continued)
Page
6.6 INSPECTION OF AIR POLLUTION CONTROLS 6-41
6.6.1 Inspection of Wet Scrubbers 6-41
6.6.2 Inspection of Dry Scrubbers 6-51
6.6.3 Inspection of Fabric Filters 6-58
6.7 REFERENCES FOR CHAPTER 6 6-66
CHAPTER 7.0 SPECIAL CONSIDERATIONS 7-1
7.1 INCINERATOR OPERATOR TRAINING AND OPERATOR
EXPERIENCE 7-1
7.2 EMERGENCY OPERATING PLAN 7-2
7.3 CROSS-MEDIA INSPECTIONS 7-2
7.3.1 A1r Pollution 7-3
7.3.2 Solid Waste 7-3
7.3.3 Inspector Multimedia Responsibilities 7-4
7.4 STARTUP AND SHUTDOWN PROCEDURES FOR HOSPITAL
WASTE INCINERATORS AND ASSOCIATED AIR
POLLUTION CONTROL DEVICE 7-6
7.4.1 Batch Feed Starved-A1r Incinerator 7-6
7.4.2 Intermittent-Duty, Starved-A1r
Inc1 nerators 7-9
7.4.3 Continuous-Duty, Starved-A1r
Inc1 nerators 7-10
7.4.4 Excess-Air Incinerators 7-11
7.4.5 Wet Scrubbers 7-12
7.4.7 Fabric Filters 7-15
7.5 WASTE HEAT BOILERS 7-17
7.6 CITIZENS COMPLAINT FOLLOWUP 7-18
7.7 REFERENCES FOR CHAPTER 7 7-18
CHAPTER 8.0 GLOSSARY 8-1
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TABLE OF CONTENTS (continued)
Page
APPENDIX A. INSPECTION CHECKLIST FOR WASTE CHARACTERIZATION A-l
APPENDIX B. INSPECTION CHECKLIST FOR INCINERATORS B-l
APPENDIX C. INSPECTION CHECKLIST FOR POLLUTION CONTROL SYSTEMS.... C-l
APPENDIX D. METHOD 9 WORK SHEET D-l
APPENDIX E. SAFETY CHECKLIST E-l
APPENDIX F. CITIZEN COMPLAINT FORM F-l
APPENDIX G. EXAMPLE INSPECTION REPORT G-l
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LIST OF TABLES
Page
TABLE 2-1. GUIDELINE EMISSION LIMITS FOR INCINERATORS BURNING
HOSPITAL WASTE 2-5
TABLE 4-1. SUMMARY OF METHOD 9 REQUIREMENTS 4-3
TABLE 4-2. PERFORMANCE SPECIFICATIONS FOR OPACITY MONITORS 4-7
TABLE 5-1. CLASSIFICATION OF HOSPITAL INCINERATORS 5-4
TABLE 5-2. WET SCRUBBER PERFORMANCE PARAMETERS 5-23
TABLE 6-1. ULTIMATE ANALYSES OF FOUR PLASTICS 6-19
TABLE 6-2. INCINERATOR INSTITUTE OF AMERICA SOLID WASTE
CLASSIFICATIONS 6-21
TABLE 6-3. MATRIX OF MEDICAL WASTE INSPECTION ACTIVITIES
ASSOCIATED WITH INSPECTION LEVELS 1, 2, 3, AND 4 6-24
TABLE 6-4. MATRIX OF COMBUSTION EQUIPMENT INSPECTION ACTIVITIES
ASSOCIATED WITH INSPECTION LEVELS 1, 2, 3, AND 4 6-32
TABLE 6-5. MATRIX OF AIR POLLUTION CONTROL DEVICE INSPECTION
ACTIVITIES ASSOCIATED WITH INSPECTION
LEVELS 1, 2, 3, AND 4 6-43
TABLE 7-1. LIST OF HAZARDOUS WASTES THAT MAY BE GENERATED AT A
MEDICAL FACILITY 7-5
IX
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LIST OF FIGURES
Page
Figure 4-1. Typical transmissometer installation for measuring
Figure 5-1.
Figure 5-2.
Figure 5-3.
Figure 5-4.
Figure 5-5.
Figure 5-6.
Schematic of a controlled-air incinerator
Control of temperature as a function of excess air....
Schematic of a batch/starved-air incinerator
Operating sequence of a waste charging hopper/ram
system
Intermittent/control led-air incinerator with vertical
primary chamber and horizontal secondary chamber....
Schematic of a continuous operation controlled-air
5-5
5-7
5-10
5-12
5-14
incinerator with mechanical charging and
ash removal
Figure 5-7.
Figure 5-8.
Figure 5-9.
Figure 5-10.
Figure 5-11.
Figure 5-12.
Figure 5-13.
Figure 5-14.
Figure 5-15.
Figure 5-16.
Figure 5-17.
Figure 5-18.
Retort multiple-chamber, excess-air Incinerator for
patho1ogical wastes
In-line excess air incinerator
Drawing for rotary kiln incinerator
Venturi configuration
Spray venturi with rectangular throat...
Vertically oriented packed-bed scrubber.
Components of a spray dryer absorber system (semiwet
process)
Components of a dry injection absorption system
(dry process)
Components of a combination spray dryer and dry
injection absorption system (semiwet/dry process)..
Schematic of pulse jet baghouse
Top access pulse jet fabric filter
Cross sectional sketch of pulse jet fabric filter.
5-16
5-17
5-19
5-21
5-25
5-26
5-29
5-32
5-33
5-34
5-40
5-41
5-43
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LIST OF FIGURES (continued)
Page
Figure 6-1. Counterflow inspection approach 6-5
Figure 6-2. Co-current inspection approach 6-6
Figure 6-3. The biological hazard symbol 6-16
xi
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1.0 INTRODUCTION
1.1 BACKGROUND
Hospitals have long used incineration for the disposal of all or part
of the wastes they generate; the practice is expected to grow in the near
future. Many States recently have established regulations governing the
disposal of infectious wastes; other States are considering such regula-
tions. The trend in these regulations is away from direct landfill ing and
toward treatment to render wastes innocuous prior to land disposal. The
primary treatment method is expected to be incineration.
At the same time that infectious waste disposal considerations are
creating pressures for increased incineration of hospital wastes, interest
in the regulation of air emissions from these sources is also rising.
Recent investigation into emissions from municipal waste incinerators has
heightened the awareness of the potential for emissions of fine particu-
late matter, acid gases, and toxic compounds (e.g., chlorinated dioxins
and furans) from hospital incinerators. This has stimulated interest in
these sources that once were considered too small to be closely
regulated. A number of States have enacted or are considering new
regulations for hospital waste incinerators (HWI's).
As new, more stringent regulations affecting HWI's raise control
costs, the economic viability of larger commercial units built to serve a
number of hospitals increases. Such facilities can take advantage of the
economies of scale of incineration and pollution control equipment and
likely will be much more able to profitably recover energy profitably than
will a small HWI with its characteristic load fluctuations.
1.2 PURPOSE
These trends in the use and regulation of HWI's provide the impetus
for this manual. The purpose of this manual is to meet the growing need
for specialized information on this source of air pollution.
This manual provides air program inspectors with a concise body of
information pertinent to the inspection of hospital waste incinerators.
1.3 SCOPE
This manual is not intended to provide detailed information on
general inspection procedures and techniques. These subjects have been
\
1-1
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well covered elsewhere.1*2 These subjects will be touched upon as
necessary to present an Integrated approach to HWI Inspections, but the
focus of this manual win be on those subject areas with greatest
relevance to HWI's. Special emphasis will be placed on matters unique to
HWI's.
Much of the information relative to the components and operating
principles of hospital waste incineration systems was taken from
"Operation and Maintenance of Medical Waste Incinerators" which is
currently under development by the U. S. Environmental Protection
Agency. Inspectors should refer to this document for detailed information
on the proper operation and maintenance of hospital waste incinerator
systems.
1.4 ORGANIZATION
In Chapter 2, general inspection information is presented. Topics
include legal authority, regulations under the Clean Air Act, Inspector
responsibilities and liabilities, and general inspection procedures.
Chapter 3 discusses safety during inspections, with emphasis on hazards
specific to HWI's and the control devices expected at such facilities.
Visible emission observation procedures are presented in Chapter 4.
In Chapter 5, background information on HWI types 1s presented.
Excess-air, starved-a1r, and rotary kiln units are discussed. Background
is also given for the types of control devices currently in use at HWI
facilities and those expected to come into use as more stringent
regulations are adopted. These include wet and dry scrubbers and fabric
filters.
The heart of this manual is presented in Chapter 6. Inspection
checklists and detailed inspection procedures are provided for Levels 2,
3, and 4 inspections of HWI's and control devices.
Special considerations are addressed 1n Chapter 7. These include HWI
operator training, emergency operating plans, cross-media Inspections,
citizen complaint followup, waste heat boilers, and startup and shutdown
procedures. Finally, a number of appendices present supplementary
materials such as inspection checklists.
1-2
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1.5 REFERENCES FOR CHAPTER 1
1. U. S. EPA Stationary Source Compliance Division, "Air Compliance
Inspection Manual," U. S. Environmental Protection Agency.
Publication No. 340/1-85-020. September 1985.
2. Richards, J. R., and Segal!, R. R., "Baseline Source Inspection
Techniques," U. S. Environmental Protection Agency. Publication
No. 340/l-85-022a. June 1985.
1-3
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2.0 GENERAL INSPECTION CONSIDERATIONS
2.1 LEGAL AUTHORITY OF THE INSPECTOR1
Section 114 of the Clean Air Act (CAA) provides the Administrator of
EPA or his authorized representative with the authority, upon presentation
of his credentials, to enter the premises of facilities subject to
regulations under the Act for the purpose of conducting onsite inspections
to monitor compliance with these regulations.
2.1.1 Scope
Inspections conducted under Section 114 extend to all things relating
to compliance with the requirements of the CAA which are within the
premises being inspected. These may include:
1. Records;
2. Files;
3. Processes;
4. Monitoring equipment;
5. Controls;
6. Sampling methods; and
7. Emissions.
2.1.2 State Authority
In accord with the intent of the CAA, much of the compliance
monitoring, including onsite inspections, is accomplished at the State
level. Section 114 of the Act allows Federal authority to be delegated to
the States to carry out that Section. Where a State has been delegated
full Section 114 authority from EPA, the same authority EPA has to
monitor, sample, inspect or copy records, and any other authority under
Section 114 can, in like manner, be exercised by the State. No
representative of EPA need accompany the State officials.
2.1.3 Authorized Representatives
The EPA does not always have the staff available to conduct all of
the compliance monitoring functions on its own. In order to accomplish
these functions, EPA frequently hires private contractors to provide
technical support for onsite inspections and sampling, among other
things. The EPA maintains that such contractors upon proper designation
are "authorized representatives" of the Administrator within the meaning
2-1
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of Section 114; however, the courts have not unanimously upheld EPA's
position. For this reason, EPA has adopted a policy that duly-authorized
contractors are used to conduct onsite inspections only in those Circuits
where Courts of Appeals' decisions have not been against the use of
contractors as authorized representatives.
The EPA's current policy on the use of contractors to conduct onsite
inspections is as follows:
1. First, Second, Third, Fourth, Fifth, Seventh, Eighth, Eleventh,
and District of Columbia Circuits. Authorized contractors may be
designated to provide technical support for inspection of facilities owned
by anyone other than Stauffer Chemical Company.
2. Ninth Circuit. Authorized contractors may be designated to
provide technical support for any inspections.
3. Sixth and Tenth Circuits. Absent express permission from
Headquarters, authorized contractors should not be designated to provide
technical support for any inspections.
2.1.4 Offslte Inspections
The EPA also has the authority to conduct unannounced, off-the-
premises inspections, such as visible emission observations.
2.2 REGULATIONS UNDER THE CLEAN AIR ACT
2.2.1 Existing Regulations
2.2.1.1 New Source Performance Standards (NSPS).2 At this time, no NSPJ
is applicable specifically to HWI's. However, two existing NSPS could
apply to very large facilities. The standard for industrial, commercial,
and institutional steam generating units (40 CFR Part 60, Subpart Db)
applies to facilities with a heat input capacity of 100 million Btu/h or
greater that recover heat to generate steam or heat water. This heat
input is greater than the capacity of any onsite HWI available at this
time but is not out of the question for a regional commercial facility.
For this NSPS to be applicable, a facility burning Type 0 waste with a
heating value of 8,500 Btu per pound would have to have a capacity of
nearly 12,000 pounds per hour (140 tons/d) or more. The standard
regulates opacity and emissions of PM, NOX, and S02.
2-2
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The standard for Incinerators (40 CFR Part 60, Subpart E) applies to
incinerators with a capacity of 50 tons/d or greater that burn more than
50 percent "municipal type waste." Under the definitions of the standard,
HWI's would seem to qualify. Even so, only the largest onsite units or
regional facilities would qualify. Currently, this standard regulates PM
emissions; the standard is being revised.
2.2.1.2 National Emission Standards for Hazardous Air Pollutants
(NESHAP's). Standards for emissions of radionuclides to the atmosphere
have been promulgated for DOE facilities (40 CFR Part 61, Subpart H) and
for other facilities (40 CFR Part 61, Subpart I). Some medical research
facilities are licensed to incinerate their radioactive wastes. At these
facilities, these wastes likely will be incinerated along with the
facility's infectious wastes, and the incinerator will be subject to the
applicable NESHAP. It is unlikely that most hospital incinerators will be
licensed to incinerate radioactive wastes, so incinerators at these
facilities are unlikely to be subject to the NESHAP's.
2.2.1.3 State Implementation Plans (SIP's). Under the CAA, a State
wishing to administer its own air quality control programs must receive
approval from EPA of its SIP. ,o be approved, the SIP is required to
include a number of specific programs, including prevention of significant
deterioration (PSD) in attainment areas, new source review (NSR) in
nonattainment areas, and air quality management plans and emission
limitations to maintain (or progress towards) attainment of national
ambient standards.
Incinerators located at hospitals are too small for PSD and NSR
programs to apply. These programs, particularly NSR, could apply to very
large regional commercial HWI's.
Some States are now regulating emissions from HWI's specifically, but
most have no specific requirements for these sources. Where emission
limits have been adopted, they are generally quite stringent. For
instance, Pennsylvania has recently (January 1988) adopted standards that
limit emissions of particulate matter from the largest HWI's (capacity
>2,000 pounds per hour) to 0.015 gr/dscf, corrected to 7 percent 02. This
limitation is based on the best demonstrated technology (BDT) determined
for municipal waste incinerators, the use of a dry scrubber followed by a
2-3
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fabric filter or ESP. Emissions of CO, HC1, and S02 are also regulated,
as 1s the opacity of the visible emissions. Several States have Imposed
regulations on new HWI's similar to those governing hazardous waste
Incinerators under the Resource Conservation and Recovery Act (RCRA):
0.08 gr/dscf (corrected to 12 percent C02) for particulate matter, 100 ppm
for CO, and 99 percent control or 4 pounds per hour for HC1, whichever is
higher. (These standards are essentially the same as the Pennsylvania
regulations for the smallest HWI's, those with capacities <500 pounds per
hour.) Although current Interest 1n Infectious waste is creating a trend
towards specific regulations, in many States the only existing regulations
that apply to HWI's are general prohibitions on excessive opacity and
odor. Table 2-1 presents emission limit guidelines currently promulgated
for several States that represent the trend towards specific HWI emission
limits.
2.2.1.4 State Air Toxics Programs. Most States have relatively new air
toxics programs to regulate toxic emissions based on the ambient
concentrations that result from operation of the source. For instance,
the Pennsylvania regulations require ambient Impact analyses for a number
of inorganic and organic substances using dispersion modeling.
2.2.1.5 Construction and Operating Permits. Because there currently are
no NSPS regulations governing HWI's, many states are promulgating
regulations of their own that Impose both emission limitations and minimum
operating conditions on the incinerator and air pollution control
devices. These types of regulations are included as part of the HWI's
construction and operating permit.
Most states require that emission sources apply for a combined
construction and operating permit; other states require both a
construction permit and an operating permit. The Inspector should become
familiar with the limitations and conditions included in the facility's
permit prior to Inspecting the HWI. Table 2-1 presents examples of the
types of emission limitations that have been promulgated in some states.
Operating condition limits may Include minimum primary and secondary
chamber temperatures, minimum gas retention time in the secondary chamber,
and minimum pressure drop across the venturi section.
2-4
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2.2.2 Possible Future Regulations
2.2.2.1 NSPS. The EPA 1s considering an NSPS for smaller boilers,
perhaps with a cutoff as low as 10 million Btu/h heat input. Such a
regulation has potential applicability to HWI's with capacities as low as
1,200 pounds per hour (assuming Type 0 wastes with a heating value of
8,500 Btu/lb) that produce steam or hot water.
2.2.2.2 SIP's. With the establishment of an ambient standard for
resplrable partlculate matter (PM10), SIP revisions are required for a
number of areas. As a source of PM10, HWI's may be addressed in these SIP
revisions with new Mission limits. This may also result 1n new emphasis
on HWI's under NSR provisions.
2.2.2.3 The Medical Waste Tracking Act of 1988. The Medical Waste
Tracking Act of 1988 was signed Into, law by President Reagan on
November 1, 1988. House Rule (HR) 3515 created a pilot program to track
infectious medical wastes in 10 states including New York, New Jersey,
Connecticut, and the States contiguous to the Great Lakes (Wisconsin,
Illinois, Michigan, Indiana, Ohio, Pennsylvania, and Minnesota).
Additionally, HR 3515 listed the following 10 categories of waste that
must be Included in the tracking system:
• Cultures and stocks of Infectious agents and associated
biologlcals, such as cultures from laboratories;
• Pathological wastes, such as tissues, organs, and body parts;
• Human blood wastes and other blood products, including serum,
plasma, and other blood components;
• Sharps that have been used in patient care, medical research, or
industrial laboratories;
• Contaminated animal carcasses, body parts, and animal bedding
exposed to Infectious agents during research;
• Surgery or autopsy wastes that came in contact with infectious
agents;
• Laboratory wastes from medical, pathological, pharmaceutical, or
other research, conaercial, or industrial laboratories that were in
contact with Infectious agents;
• Dialysis wastes that were in contact with the blood of patients
undergoing hemodialysis;
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Discarded medical equipment and parts that were in contact with
Infectious wastes; and
• Biological wastes and discarded materials contaminated with
blood, excretion, or secretions from human beings or animals that are
isolated to protect others from communicable diseases.
Additional wastes may be added by the EPA administrator. The
10 wastes must be segregated at the point of generation and must be placed
in appropriately labeled containers that will protect waste handlers and
the public from exposure. Additionally, a waste manifest system will be
implemented for generators who have their waste disposed offsite. For
waste generators who treat their waste through onsite incineration and who
do not track their waste as outlined above, a recordkeeping and reporting
requirement will be Implemented that requires the generator to report the
volume and types of medical waste Incinerated on site for 6 months after
the effective date of the tracking system. The EPA expects to publish
proposed regulations in early February 1989. Depending on the success of
the pilot program, the medical waste tracking system may be Implemented
nationwide.
2.3 INSPECTOR RESPONSIBILITIES AND LIABILITIES1
The primary role of the air compliance Inspector 1s to gather
information needed for the determination of compliance with applicable
regulations and for other enforcement-related activities, such as case
development. Closely coupled with the accomplishment of these functions
are certain responsibilities of the air compliance inspector, which
include: (1) knowing and abiding by the legal requirements of the
inspection, (2) using proper procedures for effective inspection and
evidence collection, (3) practicing accepted safety procedures,
(4) maintaining certain quality assurance standards, and (5) observing the
professional and ethical responsibilities of the government employee.
Additional Important considerations for the inspector are any potential
liabilities of his position.
2.3.1 Legal Responsibilities
It 1s essential that all inspection activities be conducted within
the legal framework established by the CAA. In particular, this
includes:
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1. Proper handling of confidential business information;
2. Presentation of proper credentials and plant entry at reasonable
times;
3. Protection of the company's and its personnel's legal rights
under the U.S. Constitution;
4. Knowledge of all applicable statutes, regulations, and permit
conditions; and
5. Use of not1ce(s) and receipts, if appropriate.
2.3.2 Procedural Responsibilities
The Inspector must be familiar with and adhere to, when possible, all
general Inspection procedures and evidence gathering techniques. This
will ensure accurate Inspections and avoid the possibility of endangering
a legal proceeding on procedural grounds.
2.3.2.1 Inspection Procedures. Inspectors should observe standard
procedures for conducting each portion of the inspection, when possible.
All deviations should be clearly documented. The accepted general
Inspection procedures are covered in detail 1n Section 2.4 of this
chapter.
2.3.2.2 Evidence Collection. Inspectors must be familiar with general
evidence gathering techniques. Because the government's case in an
enforcement action depends on the evidence gathered by the inspector, it
is Imperative that the Inspector keep detailed records of each
inspection. These records will serve as an aid in preparing the
inspection report, in determining the appropriate enforcement response,
and in giving testimony in an enforcement case. Documentation of evidence
1s covered 1n Chapter 2.0 of this manual. Several responsibilities
Involved in evidence collection and presentation should be addressed
here. Specifically, Inspectors must:
1. Know how to substantiate facts with items of evidence, including
samples, photographs, document copies, statements from persons, and
personal observations.
2. Know how to detect lack of good faith during interviews with
company personnel.
3. Be familiar with all applicable regulations and what type of
information is required to determine compliance with each.
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4. Be able to evaluate what documentation is necessary (routine
inspection).
5. Collect evidence in a manner that will be incontestable in legal
proceedings.
6. Be able to write clear, informative inspection reports.
7. Know how to testify in court and at administrative hearings.
2.3.3 Safety Responsibilities
The inspection of air pollution control equipment and related work in
other areas of Industrial facilities generally involves potential exposure
to numerous hazards. The Inspector must, at all times, avoid putting
him/herself or any plant personnel at unnecessary risk. To accomplish
this, it 1s the inspector's responsibility to:
1. Know and observe all plant safety requirements, warning signals,
and emergency procedures.
2. Know and observe all agency safety requirements, procedures, and
policies.
3. Remain current in safety practices and procedures by regulaY
participation 1n agency safety training.
4. Use any safety equipment required by the facility being inspected
1n addition to that required by the agency.
5. Use safety equipment in accordance with agency guidance and label
instructions.
6. Maintain safety equipment in good condition and proper working
order.
7. Dress appropriately for each inspection activity, including
protective clothing, if appropriate.
Chapter 3.0 of this manual and listed references address inspection
safety procedures and other safety-related questions in more detail.
2.3.4 Professional and Ethical Responsibilities
As professionals and employees of Federal, State, or local
authorities, inspectors are expected to perform their duties with
Integrity and professionalism. Procedures and requirements ensuring
ethical actions have been worked out through many years of governmental
inspection activities. These procedures and standards of conduct have
evolved for the protection of the individual and the Agency, as well as
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Industry. The Inspector is constantly in a position to set an example for
private industry, to encourage concern for health and safety in the
environment, and to promote compliance with the laws that protect the
environment and the health and safety of employees.
Specifically, the inspector should always consider and observe the
following list of responsibilities.
2.3.4.1 U.S. Constitution. All investigations are to be conducted with
the framework of the U.S. Constitution and with due regard for individual
rights regardless of race, sex, creed, or national origin.
2.3.4.2 Employee Conduct. Inspectors are to conduct themselves at all
tiroes in accordance with the regulations prescribing EPA Employee
Responsibilities and Conduct, codified in 40 CFR Part 3.
In the absence of specific guidelines regarding conduct during an
inspection, it is recommended that State and local agency inspectors
become familiar with these regulations and conduct themselves in a similar
manner.
2.3.4.3 Objectivity. The facts of an Investigation are to be developed
and reported completely, accurately, and objectively. In the course of an
investigation, any act or failure to act motivated by reason of private
gain is illegal. Actions which could be construed as such should be
scrupulously avoided.
2.3.4.4 Knowledge. A continuing effort to improve professional knowled
and technical skill in the investigation field should be made. The
inspector should keep abreast of changes in the field of air pollution,
including current regulations, EPA and other agency policies, control
technology, methodology, and safety considerations.
2.3.4.5 Professional Attitude. The inspector is a representative of EPi
or State or local government and is often the initial or only contact
between the appropriate agency and industry. In dealing with facility
representatives and employees, inspectors must be dignified, tactful,
courteous, and diplomatic. They should be especially careful not to
infringe on union/company agreements. A firm but responsive attitude will
help to establish an atmosphere of cooperation and should foster good
working relations. The inspector should always strive to obtain the
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respect of, Inspire confidence in, and maintain good will with industry
and the public.
2.3.4.6 Attire. Inspectors should dress appropriately, including wearing
protective clothing or equipment, for the activity in which they are
engaged.
2.3.4.7 Industry, Public, and Consumer Relations. All information
acquired 1n the course of an inspector's duties is for official use
only. Inspectors should not speak of any product, manufacturer, or person
in a derogatory manner.
2.3.4.8 Gifts, Favors, Luncheons. Inspectors should not accept favors or
benefits under circumstances that might be construed as influencing the
performance of governmental duties. The 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.
2.3.4.9 Requests for Information. Although EPA has a general "open-door"
policy on releasing Information to the public, this policy does not extend
to Information related to the suspicion of a violation, evidence of
possible misconduct, or confidential business Information.
2.3.5 Quality Assurance Responsibilities
The Inspector assumes primary responsibility for ensuring the quality
of data generated as a result of the inspection. The inspector should
thus adhere to quality assurance procedures appropriate to the type of
data being generated. In general, quality assurance procedures are
developed concerning the following elements:
1. Valid data collection;
2. Approved, standard methods;
3. Control of service, equipment, supplies;
4. Quality analytical techniques; and
5. Standard data handling and reporting.
2.3.6 Potential Liabilities
In addition to their responsibilities, inspectors should also be
aware of potential personal liabilities. Some examples of the most common
liabilities are listed below. The inspector should consult his/her
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supervisor or agency legal staff for exact legal determinations on
personal liability.
2.3.6.1 Confidential Business Information. Under Section 1905 of
Title 18 of the United States Code, Federal employees can be fined,
imprisoned, or both for disclosure of confidential business information.
2.3.6.2 Wa1vers/V1s1tor Releases. Some companies waivers or visitor
releases, 1f- signed, purport to make the person signing liable for certain
acts he or she might commit on plant property. These must never be signed
by the Inspector.
2.3.6.3 Authority. In some cases, the inspector could be held liable f
actions committed beyond the scope of his/her authority; the Inspector
must always know exactly what his/her authority is.
2.4 GENERAL INSPECTION PROCEDURES
This section briefly describes some of the legal and administrative
procedures common to most air compliance inspections. More complete
discussion of the legal and administrative procedures common to most
inspections can be found in Chapter 3 of the Air Compliance Inspection
Manual, EPA-340/1-85-020, September 1985. These procedures will help to
ensure that technical Inspections are complete, current, and legally
defensible and that the data gathered can be used effectively in later
compliance monitoring and determination.
These general inspection procedures can be categorized by the order
in which they occur in the Inspection process: (1) preinspection
preparation, (2) preentry observations, (3) entry, and (4) contents and
timing. These categories are discussed below.
2.4.1 Preinspection Preparation
Preinspection preparation is always necessary to ensure effective use
of the Inspector's time and the facility personnel's time and to ensure
that the Inspection 1s focused properly on collecting relevant data and
Information. Preinspection preparation Involves:
1. Review of facility background;
2. Development of an inspection plan;
3. Notifications; and
4. Equipment preparation.
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2.4.1.1 Review of Facility Background. A review of the available
background Information on the infectious waste incinerator to be inspected
is essential to the overall success of the inspection. The review should
enable the inspector to become familiar with the incinerator's design,
operating procedures, and emission characteristics; conduct the inspection
in a timely manner; minimize inconvenience to the facility by not
requesting unnecessary data such as that previously provided to EPA or
another agency; conduct an efficient but thorough inspection; clarify
technical and legal issues before entry; and prepare a useful inspection
report. The types of information that should be reviewed are listed
below.
1. Basic facility information.
a. Names, titles, and phone numbers of facility representatives;
b. Maps showing facility location and geographic relationship to
residences, etc., potentially impacted by emissions;
c. Incinerator type and capacity;
d. Types of wastes incinerated;
e. Flowsheets Identifying control devices and monitors; and
f. Safety equipment requirements.
2. Pollution control equipment and other relevant equipment data.
a. Description and design data for control devices;
b. Baseline performance data for control equipment;
c. Continuous emission monitoring system(s) data;
d. Previous inspection checklists (and reports); and
e. Information on maintenance program, if available.
3. Regulations, requirements, and limitations.
a. Most recent permits for facility sources;
b. Applicable Federal, State, and local regulations and
requirements;
c. Special exemptions and waivers, if any; and
d. Acceptable operating conditions.
4. Facility compliance and enforcement history.
a. Previous inspection reports;
b. Complaint history including reports, followups, findings,
remedial action;
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c. Past conditions of noncompllance;
d. Previous enforcement actions;
e. Pending enforcement actions, compliance schedules, and/or
variances; and
f. Self-monitoring data and reports.
2.4.1.2 Background Information Sources. The recommended sources for
obtaining the background information outlined 1n Section 2.4.1.1 include:
1. Inspector's "working" file. The inspector's own concise file for
a facility containing basic information on the Incinerator, flowsheets,
baseline performance data for control equipment and the Incinerator,
chronology of enforcement-related actions, recent permits, and safety
equ1pment requ1rement s.
2. Regional office files and data bases. These files should include
much of the information needed Including inspection reports, permits and
permit applications, compliance and enforcement history, exemption or
waiver Information, and some self-monitoring data.
3. State/local files and contacts. These should be used to
supplement and update the Information available in the EPA Regional office
files.
4. Laws and regulations. The CAA and related regulations establish
emission standards, controls, procedures, and other requirements
applicable to a facility. State and local laws and regulations also
should be considered.
5. Technical reports, documents, and guidelines. These can often be
valuable in providing information and/or guidance concerning incineration,
control techniques, performance advantages and limitations of particular
types of control equipment, and specific Inspection procedures.
2.4.1.3 Development of An Inspection Plan. Based on the review of
the facility background information and the intended purpose of the
inspection, the inspector should develop an Inspection plan that should
address the following items:
1. Inspection objectives. Identify the precise purpose of the
inspection in terms of what it will accomplish.
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2. Tasks. Identify the specific tasks that will accomplish the
inspection objectives including the exact information that must be
collected.
3. Procedures. Specify the procedures to be used in completing the
tasks, especially special or unfamiliar procedures.
4. Resources. List the equipment and identify the personnel that
will be required.
5. Schedule. Present an estimate of the time required to conduct
the Inspection; suggest a feasible date for the inspection (when the
incinerator will be operating at representative conditions).
2.4.1.4 Notification of the Facility. The policies of EPA Regional
offices vary concerning giving a facility advance notification of an
inspection. In a recent EPA policy memo entitled "Final Guidance on Use
of Unannounced Inspections," however, the Stationary Source Compliance
Division recommends that all Regional inspection programs incorporate
unannounced inspections as part of their overall inspection approach.
The advantages of unannounced inspections are: (1) the source can be
observed under normal operating conditions because the source does not
have time to prepare for the inspection; (2) visible emissions and
O&M-type problems and violations can be detected; (3) the source's level
of attention to Its compliance status is Increased; and (4) the
seriousness of the Agency's attitude toward surveillance is emphasized.
The potential negative aspects of performing unannounced inspections
are: (1) the source may not be operating or key plant personnel may not
be available; and (2) there could be an adverse impact on EPA/State or
EPA/source relations. However, it has been demonstrated by the Regional
offices that already use unannounced inspections that, in the majority of
cases, these drawbacks can be overcome.
2.4.2 Preentry Observations
Two types of observations conducted prior to facility entry have been
shown to be valuable in the determination of facility compliance:
observations of the facility surroundings and vtsible emission
observations.
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2.4.2.1 Facility Surroundings Observations. Observations of areas
surrounding the facility prior to entry may reveal problems related to
operational practices and pollutant emissions. These observations can
include:
1. Odors downwind of the facility;
2. Deposits on cars parked nearby;
3. Other signs of "soot" downwind of the facility; and
4. Conditions around the waste storage area.
If odors are observed, weather conditions, including wind direction,
should be noted for inclusion in the inspection report.
2.4.2.2 Visible Emissions Observations. In addition to observing the
facility surroundings prior to entry, the inspector may also perform
visible emission observations at that time. The incinerator/control
device stack outlet may not be visible from a location outside the plant
property lines, but those that are may be conveniently read before
entry. In cases where the incinerator has an emergency bypass stack, the
observer should note whether the bypass stack was "activated." Visible
emission observation procedures are discussed further in Chapter 4.
It 1s appropriate for the inspector to inform facility officials if
excess visible emissions are observed. At the same time, the inspector
should identify the cause of the excess emissions to enable facility
personnel to promptly evaluate, respond to, and correct the problem.
There may be State statutes that require notifications; the inspector
should be aware of these before visiting the plant.
2.4.3 Entry
This section describes the accepted procedures under the CAA for
entry to a facility to conduct an onslte inspection. Detailed procedures
for obtaining an inspection warrant in the case of refusal of entry are
not presented because refusal is not prevalent and this subject is covered
in detail 1n other publications. However, should entry be refused, the
inspector should consult the EPA Regional Counsel's office for assistance.
2.4.3.1 Authority. The CAA authorizes plant entry for the purposes
of inspection. Specifically, Section 114 of the Act states:1
... the Administrator or his authorized representative, upon
presentation of his credentials shall have a right of entry
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to, upon or through any premises of such person or in which
any records required to be maintained ... are located, and
may at reasonable times have access to and copy any records,
inspect any monitoring equipment or method . . . and sample
any emissions which such person is required to sample . . . ."
2.4.3.2 Arrival. The inspector must arrive at the facility
(hospital) during normal working hours. Entry through the main lobby is
recommended unless the inspector has been previously instructed
otherwise. As soon as the inspector arrives on the premises he should
locate a responsible hospital official usually the hospital administrator,
environmental manager, or chief engineer. In the case of an announced
inspection, this person would most probably be the official to whom
notification was made. The inspector should note the name and title of
this plant representative.
2.4.3.3 Credentials. Upon meeting the appropriate official, the
inspector should introduce himself or herself as an EPA inspector, present
the official with the proper EPA credentials, and state the reason for
requesting entry. The credentials provide the official with the assurance
that the inspector is a lawful representative of the Agency. Each office
of the EPA issues its own credentials; most include the inspector's photo-
graph, signature, physical description, (age, height, weight, color of
hair and eyes), and the authority for the inspection. Credentials must be
presented whether or not identification is requested.1 After facility
officials have examined the credentials, they may telephone the
appropriate EPA office for verification of the inspector's identifica-
tion. Credentials should never leave the sight of the inspector.
2.4.3.4 Consent. Consent to inspect the premises must be given by
the owner, operator, or his representatives at the time of the
Inspection. As long as the inspector is allowed to enter, entry is
considered voluntary and consensual, unless the inspector is expressly
told to leave the premises. Express consent is not necessary; absence of
an express denial constitutes consent.1
2.4.3.5 Inspection Documentation. The air compliance inspection is
generally conducted to achieve one or more of the following three major
objectives:
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1. To provide data and other information for making a compliance
determination;
2. To provide evidentiary support for some type of enforcement
action; and
3. To gather data required for other Agency functions.
Taking physical samples, reviewing records, and documenting facility
operations are the methods used by the inspector to develop the
documentary support required to accomplish these objectives. The
documentation from the inspection establishes the actual conditions
existing at the time of the Inspection so that the evidence of these
conditions may be objectively examined at a later time in the course of an
enforcement proceeding or other compliance-related activity.
Documentation is a general term referring to all print and mechanical
redla produced, copied, or taken by an inspector to provide evidence of
facility status. Types of documentation include the field notebook, field
notes and checklists, visible emission observation forms, drawings,
flowsheets, maps, lab analyses of samples, cha1n-of-custody records,
statements, copies of records, printed matter, and photographs. Any
documentation gathered or produced in the course of the Inspection process
•ay eventually become part of an enforcement proceeding. It 1s the
Inspector's responsibility to recognize this possibility and ensure that
all documentation can pass later legal scrutiny.
2.4.3.5.1 Inspector's field notebook and field notes. The core of all
documentation relating to an inspection is the inspector's field notebook
or field notes, which provide accurate and inclusive documentation of all
field activities. Even if certain data or other documentation is not
actually included 1n the notebook or notes, reference should be made in
the notebook or notes to the additional data or documentation such that it
1s completely Identified and 1t 1s clear how 1t fits Into the Inspection
scheme.
The field notebook and/or notes form the basis for both the
inspection report and the evidence package and should contain only facts
and pertinent observations. Language should be objective, factual, and
free of personal feelings or terminology that might prove inappropriate.
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Because the inspector may eventually be called upon to testify In an
enforcement proceeding, or field data gathered during the inspection may
be entered Into evidence, it is imperative that the inspector keep
detailed records of inspections, investigations, samples collected, and
related inspection functions. The types of information that should be
entered into the field notebook or notes include:
1. Observations. All conditions, practices, and other observations
relevant to the inspection objectives or that will contribute to valid
evidence should be recorded.
2. Procedures. Inspectors should list or reference all procedures
followed during the inspection such as those of entry, sampling, records
inspection, and document preparation. Such information could help avoid
damage to case proceedings on procedural grounds.
3. Unusual conditions and problems. Unusual conditions and problems
should be recorded and described in detail.
4. Documents and photographs. All documents taken or prepared by
the inspector should be noted and related to specific inspection
activities. (For example, photographs taken at a sampling site should be
listed, described, and related to the specific sample number.)
5. General Information. Names and titles of facility personnel and
the activities they perform should be listed along with other general
information. Pertinent statements made by these people should be
recorded. Information about a facility's recordkeeping procedures may be
useful in later inspections.
The field notebook is a part of the Agency's files and is not to be
considered the Inspector's personal record although copies may be made for
the inspector's "working file." Notebooks are usually held indefinitely
pending disposition instructions.
2.4.3.5.2 The visible emission observation form. Since visible
emission (VE) observations are such a frequently used enforcement tool, a
separate form has been developed for recording data from the VE observa-
tion (see Appendix D). This form has been designed to include all the
supporting documentation necessary, in most cases, for VE observation data
to be accepted as evidence of a violation. Thus, it 1s recommended that
the inspector utilize this form for recording opacity observations; an
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appropriate reference should be made to the form in the field notebook or
notes.
2.4.4 Contents and Timing
During the inspection, the inspector collects and substantiates
inspection data that may later be used as evidence in an enforcement
proceeding. Upon returning to the office, the inspector is responsible for
ensuring that these data are organized and arranged so that other Agency
personnel may make maximum use of them. Thus, the file update and
inspection report preparation are an important part of the inspection
process. These should both be done as soon as possible after the
inspection to ensure that all events of the inspection are still fresh in
the Inspector's memory. The inspector must be able to confirm during a
later enforcement proceeding that the information contained in the
inspection report is true.
2.4.4.1 File Update. The U. S. EPA and Its Regional offices utilize
several types of "files" for facility information storage, Including
computer data bases (the Compliance Data System [CDS] and the National
Emissions Data System [NEDS]) and hard copy storage (the Agency source
files). The inspector should review the relevant CDS files for the
inspected facility to determine if any of the data gathered during the
inspection can be used to fill gaps in the files or to update file
entries. The CDS data form the basis for virtually all Agency reporting on
compliance status, and, therefore, a current data base is absolutely
essential to Agency programs for use in making air management planning and
budgetary decisions. The NEDS files and any State files equivalent to CDS
and NEDS also should be reviewed and updated with information gathered
during the inspection.
The Agency files, particularly those at the Regional offices, usually
contain the hard copies of all information, correspondence, reports, etc.,
relevant to a particular facility. Examples of such items are listed
below.
1. General facility information;
2. Correspondence to facility;
3. Correspondence from facility;
4. Permit applications;
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5. Permits;
6. Facility layout;
7. Flowcharts;
8. Raw data from Inspections;
9. Inspection reports;
10. Source test reports;
11. Excess emission reports;
12. Case development workups; and
13. Agency notes, etc., on compliance actions.
The inspector's data should be used to update the general facility
information including plant contact, correct address, changes in production
rates, new flowcharts, layouts, etc.; of course, the inspector's raw data
and inspection report will be added to the file.
At this time, the inspector's "working" file on the facility (see
description in Section 2.4.1.2.) should also be updated. This task should
not require much effort because the "working" file is a summary file for
the inspector's use; and updating the "working" file will enable the
Inspector to retrieve information on a particular facility quickly in the
future.
2.4.4.2 Report Content and Preparation. The inspector's Inspection
report serves two very important purposes in Agency operations: (1) 1t
provides other Agency personnel with easy access to the Inspection
information, which is organized into a comprehensive, usable document; and
(2) it constitutes a major part of the evidence package on the inspection
and will be available for subsequent enforcement proceedings and/or other
types of compliance-related followup activities. To serve these purposes,
the information contained 1n the inspection report must be:
1. Accurate. All information must be factual and based on sound
inspection practices. Observations should be the verifiable result of
firsthand knowledge. Compliance and enforcement personnel must be able to
depend on the accuracy of all information.
2- Relevant. Information In an inspection report should be pertinent
to the objectives of Inspection. Irrelevant facts and data will clutter a
report and may reduce Its clarity and usefulness.
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3. Comprehensive. Suspected violation(s) should be substantiated by
as much factual, relevant information as is feasible to gather. The more
comprehensive the evidence is, the better and easier the outcome of any
enforcement action will be.
4. Coordinated. 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
clearly referenced so that anyone reading the report will get a complete,
clear overview of the situation.
5. Objective. Information should be objective and factual; the
report should not speculate on the ultimate result of any factual
findings.
6. Clear. The information in the report should be presented in a
clear, we11-organized manner.
7. Neat and legible. Allow time to prepare a neat, legible report.
2.4.4.2.1 Elements of the inspection report. Although specific
information contained in the inspection report will vary depending upon the
inspection objectives, most reports will contain the same basic elements:
1. Cover page;
2. Narrative report; and
3. Documentary support.
Cover page. The cover page provides easily accessible basic facility
information. It should include:
1. Facility name and address;
2. Facility identification number;
3. Facility contact and/or representative (including phone number);
4. Type of inspection;
5. Date of inspection; and
6. Inspector's name.
Narrative report. The narrative portion of an inspection report
should be a concise, factual summary of observations and activities. The
narrative should be logically organized, legible, and supported by specific
references to accompanying documentary support.
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Documentary support. The documentary support is all evidence referred
to in the inspection report. It will include:
1. Inspector's field notes, forms, checklists;
2. Drawings, charts, etc.;
3. Photographs;
4. Analysis results for samples collected;
5. Statements taken; and
6. Visible emission observation forms.
2.4.4.2.2 Inspection report preparation. The general work plan
presented below will simplify preparation of the inspection report and will
help ensure that information is organized and in a useable form. The 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. Gaps may need to be
filled by a phone call or, in unusual circumstances, by a followup visit to
the facility.
Organizing the material. The information may be organized in any one
of several ways depending on individual preference but, whatever
organization is selected, the material should be presented in a logical,
comprehensive manner. The narrative should be organized so that the
information will be easily understood by the reader.
Referencing accompanying material. All documentary support
accompanying a narrative report should be clearly referenced so that the
reader will be able to locate these documents easily. All documentary
support should be checked for clarity prior to 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 need only refer to routine procedures and practices
used during the inspection but should describe in detail facts relating to
potential violations and discrepancies.
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If the Inspector follows the steps presented, the report should
develop logically from the organizational framework of the inspection. In
writing the narrative, the inspector should keep the following in mind:
1. Keep sentences short, simple, and direct;
2. Use an active, rather than passive style: (e.g., "He said
that ..." rather than "It was said that . . .");
3. Keep paragraphs brief and to the point;
4. Avoid repetition; and
5. Proofread the narrative carefully.
2.4.4.2.3 Outline of narrative report. A basic format which can be
adapted for most narrative reports is outlined below.
1. General inspection information.
a. Inspection objectives;
b. Facility selection scheme; and
c. Inspection facts (date, time, location, plant official, etc.).
2. Summary of findings.
a. Factual compliance findings (Include problem areas);
b. Compliance status with applicable regulations;
c. Administrative problems (as with entry, withdrawal of consent,
etc.); and
d. Recommendation for future action (if appropriate).
3. Facility information.
a. Incinerator type and size;
b. Source/type of Infectious waste;
c. Operating schedule
d. Control equipment;
e. Applicable regulations; and
f. Enforcement history.
4. Inspection procedures and detail of findings.
a. Reference to standard inspection procedures used;
b. Description of nonroutine inspection procedures used;
c. Reference to attached inspection data;
d. Reference to any statements taken;
e. Reference to photographs, if relevant;
f. Reference to any drawings, charts, etc., made;
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g. Reference to visible emission observation forms; and
h. List of records reviewed and inadequacies found.
5. Sampling.
a. Reference to methods used;
b. Reference to analytical results attached; and
c. Chain of custody information.
6. Attachments—11st of all documentary support attached.
2.4.4.2.4 Confidential business information. Data or information for
which the source requests treatment as confidential business information
must be placed in the Agency's confidential files in accordance with 40 CFR
Part 2 and cannot be included in the report. The report should, however,
refer to the fact that a particular type of information has been placed in
the confidential files. Alternatively, the report may include the
confidential information; however, the entire inspection report must then
be treated as a confidential document (see Section 3.8 in Reference 1 for a
more complete discussion).
2.5 REFERENCES FOR CHAPTER 2
1. U. S. EPA Stationary Source Compliance Division, "Air Compliance
Inspection Manual," U. S. Environmental Protection Agency. Publication
No. 340/1-85-020. September 1985.
2. Hospital Waste Combustion Study Data Gathering Phase. Final Report.
U. S. Environmental Protection Agency, Office of Air Quality Planning
and Standards, Research Triangle Park, N.C. EPA-450/3-88-017.
December 1988.
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3.0 INSPECTION SAFETY
3.1 SCOPE
It 1s not the purpose of this chapter to present an exhaustive
discussion of potential health and safety hazards, EPA safety policies, or
general safety procedures. While these subjects are important to every
inspector, they have been well covered in the Air Compliance Inspection
Manual (EPA-340/1-85-020). Inspection personnel are encouraged
to consult this manual and become familiar with these subjects.
The information presented in this chapter is divided into two
sections. The first consists of general inspection guidelines applicable
to hospital waste incinerator (HWI) facilities. These are presented
briefly in a list. The second section is subdivided by the type of
equipment to be inspected and gives safety considerations specific to
each.
Although the information presented in this chapter is tailored to the
Inspection of HWI facilities, no manual can encompass every health or
safety hazard that might be encountered at a given facility. Inspectors
must take the responsibility for recognizing site-specific hazards and
taking appropriate action to minimize the danger. Nothing should be done
that may endanger the inspector or plant personnel.
3.2 SAFETY GUIDELINES
1. Exercise extreme caution in the vicinity of infectious wastes.
Never handle infectious wastes. Treat all wastes as infectious wastes,
even those wastes not identified as such (i.e., not in a red bag).
Puncture by infected needles, broken glass, or other sharp objects
("sharps") poses the single greatest hazard at a hospital incinerator.
Treat all waste bags as though they contain sharps, even if sharps are
typically handled separately. Assume any spillage in the waste handling
area is infectious and avoid contact.
2. Exercise extreme caution in the vicinity of incinerator ash. Do
not handle the incinerator ash. During some inspections, it may be
necessary to obtain a sample of the incinerator ash for analysis. In such
instances, the inspector should ask the incinerator operator or other
facility personnel familiar with the hazards associated with the handling
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of infectious wastes and sharps to take a sample of the ash. The
inspector should recommend safety precautions to be taken by the sampler
and should provide sampling tools (e.g., a sterile plastic trowel) and
sample jar. The sampler should wear protective clothing, thick rubber or
plastic gloves, eye protection, and a respirator or dust mask filter. If
the ash has not been quenched with water, the sampler should carefully
spray the ash both to douse any hot spots and to. prevent fugitive
emissions. In taking the sample, the sampler should use the sampling
trowel with care 1n removing material from different areas of the ash pile
so as not to cause fugitive dust emissions or cause puncture wounds from
sharps. Although the ash is theoretically decontaminated, safety
precautions still should be followed because the possibility of
injury/infection exists due to the presence of sharps.
3. Determine whether a radioactivity hazard exists and take
appropriate protective measures. Medical research facilities, including
those at hospitals, may be licensed to incinerate radioactive wastes. At
these facilities, such wastes are typically incinerated along with other
wastes. Prior to the inspection, determine whether the facility is
licensed to incinerate radioactive wastes. If so, ascertain the
appropriate safety procedures and equipment, if applicable, from facility
personnel or the radiation enforcement agency (NRC or analogous State
agency). If possible, arrange a joint inspection with the radiation
enforcement agency. Individuals required to enter the radioactive waste
incinerator area to perform their jobs (this would include air agency
inspectors) are entitled by law to see the incineration license. Examine
the license to determine what materials may be incinerated and any waste
or ash handling requirements. If the terms of the license are being
violated, the Inspection should be terminated immediately, and the
radiation enforcement agency should be notified.
4. Internal inspections are unnecessary. Offline equipment at
incinerator facilities including the incinerator and air pollution control
devices may have a variety of infection, inhalation, asphyxiation, thermal
burn, chemical burn, eye, and falling hazards. During a normal
inspection, regulatory agency inspectors should not enter equipment even
when it appears to be properly locked out and/or it is occupied by plant
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maintenance personnel. All necessary inspection information can be
obtained from outside the equipment. Sufficient time and appropriate
safety equipment are not normally available during an inspection to ensure
safety.
While it is not usually possible to gain entrance inside equipment,
an inspector may wish to schedule a visit or followup visit while
regularly scheduled preventive maintenance is being performed. All safety
precautions should be strictly adhered to including lockout of all
equipment and disconnection of the power supply.
5. Take all personal safety equipment. The minimum safety
equipment for inspecting incinerators consists of gloves, safety glasses,
safety shoes, sterile eye wash bottles, and a hard hat. In some cases,
more sophisticated safety equipment (e.g., half-face respirator with acid
gas cartridges or disposable dust masks) is necessary.
6. Use protective clothing and gloves. This equipment is needed
when there is a risk of contact with infectious wastes, incinerator ash,
air pollution control device solids, alkaline materials, or waste
sludges. Gloves are also needed for climbing abrasive and/or hot
ladders. Contaminated work clothes should either be discarded pr washed
separately from personal cloths.
7. Wear hearing protection. Hearing protection should be used
whenever required by the facility and whenever it is difficult to hear
another person speaking normally from a distance of 3 feet.
8. Avoid areas of suspected high pollutant concentration. Avoid
areas such as malfunctioning incinerators operating at slight positive
pressures, leaking expansion joints downstream of induced draft fans,
fugitive emissions from positive pressure equipment, and any area with
poor ventilation. Assume that any fugitives or stack emissions may
contain infectious agents or acid gases. Even if a respirator is worn, it
provides only limited protection.
9. Flush eyes contacted by alkaline materials. It is important to
flush eyes as soon as possible after alkaline materials such as calcium
hydroxide or quick limes are contacted. Flush for 15 to 30 minutes. Get
medical attention even if you think the exposure was minor.
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10. Shower Immediately if contacted by alkaline materials. In the
unlikely event that you are splashed with alkaline material, remove
affected clothing and shower immediately for a period of at least
15 minutes.
11. Use grounding/bonding cables on probes. This is especially
important downstream of electrostatic precipltators due to the
possibilities of Injuries resulting from severe muscle spasms caused by
contact with high static voltages.
12. Avoid severely vibrating equipment. Equipment such as fans can
disintegrate suddenly. Notify plant personnel immediately of the
condition and leave the area.
13. Facility personnel must be present during the inspection. Never
conduct inspections alone. Facility personnel accompanying you must be
knowledgeable in incinerator operations, general safety procedures, and
emergency procedures.
14. Follow all facility and agency safety requirements. Limit the
inspection as necessary to ensure that you completely adhere to all
facility and agency requirements.
15. Do not ask facility personnel to take unreasonable risks.
Common problem areas include sampling high pH liquors, testing gas
streams, working near hot ductwork, and working in areas with high
pollutant concentrations.
16. Do not do anything which appears dangerous. If you think that
it may be dangerous, it probably is. Do not abdicate your safety judgment
to facility personnel who may or may not be safety conscious.
17. Never hurry during inspections. This causes careless walking
and climbing accidents.
18. Interrupt the inspection if you feel sick. Interrupt the
inspection immediately whenever you feel any of the following symptoms:
headache, nausea, dizziness, drowsiness, loss of coordination, chest
pains, shortness of breath, vomiting, and eye or nose irritation. These
symptoms may be caused by exposure to toxic pollutants even though there
is no odor.
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3.3 EQUIPMENT-SPECIFIC SAFETY CONSIDERATIONS
Incinerators and add-on control devices are typically operated at
negative pressure, I.e., the system uses an induced draft fan located
downstream from the equipment. However, this is not always the case; the
inspector should not assume negative pressure. Before beginning the
inspection of the equipment, the inspector should discuss the
configuration of the system to determine if any components are under
positive pressure. Inhalation hazards are much greater around equipment
under positive pressure because the direction of flow at any leaks will be
from within the equipment to the outside. These hazards are diminished at
negative pressure components because outside air is drawn into the
equipment at any openings. In the material that follows, inhalation
hazards are discussed as if the equipment is at positive pressure. Where
the equipment is under negative pressure, these hazards should be
considered but are not likely to pose a grave threat. Inhalation hazards
associated with HWI facilities include but are not limited to infectious
microorganisms, hydrogen chloride, toxic organic compounds, carbon
monoxide, and heavy metal enriched flyash. At facilities licensed to
incinerate radioactive wastes, gas streams may also carry radioactive
materials.
3.3.1 Incinerators
3.3.1.1 Waste Storage and Handling Areas. All wastes should be
treated as infectious wastes, regardless of labeling. Any liquids spilled
in storage or handling areas should be considered infectious. All bags
and other waste containers should be assumed to contain sharps, even when
standard procedures call for sharps to be segregated from other wastes or
contained within special rigid containers.
Direct skin contact with wastes should be scrupulously avoided.
Gloves, protective clothing, and impermeable footware are required when
there is any possiblllity of contact. The inspector should not open
infectious waste containers or otherwise handle the wastes. At facilities
licensed to incinerate radioactive wastes, the inspector should be
thoroughly familiar with any special waste storage or handling
requirements and should carefully observe all protective equipment and
safety requirements.
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In addition to the normal safety precautions taken around moving
machinery, inspectors evaluating incinerator feed mechanisms should take
precautions to avoid exposure to infectious agents that could be emitted
to the atmosphere during charging. Never peer into hoppers or ram feeders
as flying objects could result in injury or exposure.
3.3.1.2 Eye Hazards in Observing Combustion. Never open observation
doors or charging doors to peer into the incinerator during operation.
Ideally, the incinerator will have sealed (i.e., glass) view ports that
can be used for viewing the combustion chamber. However, if the
incinerator does not have sealed viewports, do not open inspection or
cleanout doors.
3.3.1.3 Burns. Incinerators operate at very high temperatures, and
the potential for hot surfaces is high. Contact with the incinerator
chamber walls, heat recovery equipment, ductwork, and stack surfaces
should be avoided. Also, sampling probes may be very hot when removed
from hot stacks and vents.
3.3.1.4 Incinerator Ash. While the incinerator ash from a properly
operated HWI is not likely to be infectious or otherwize hazardous,
caution still should be exercised to avoid skin contact or inhalation.
Residues of incomplete combustion may be infectious or, more likely,
toxic. The ash of incinerators licensed for radioactive wastes may be
radioactive and require special handling. The inspector should
familiarize him/herself with any special safety procedures and equipment
needs and should avoid contact with the ash.
3.3.2 Wet Scrubbers
3.3.2.1 Venturi's at High Pressure. Positive pressure venturi
scrubbers may operate at much higher positive static pressures than other
types of air pollution control systems. Furthermore, there is a signifi-
cant potential for corrosion and erosion of the scrubber vessel and duct-
work. For these reasons, fugitive leaks are a common problem. The
inhalation hazards can include asphyxiants, toxic gases, toxic particu-
late, and, at facilities licensed for radioactive wastes, radioactive
materials. Inspectors should avoid all areas with obvious leaks and any
areas with poor ventilation. Additionally, access hatches or viewing
ports should not be opened during the inspection because of the risk of
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eye injuries. During Level 3 and Level 4 inspections, only small-diameter
sampling ports should be used.
3.3.2.2 Slip Hazards. Extreme care is often necessary when walking
around the scrubber and when climbing access ladders. Slip hazards can be
created by the water droplets reentrained in the exhaust gas, by the
liquor draining from the pumps, and by the liquor seeping from pipes and
tanks. These slip hazards are not always obvious. Furthermore, freezing
can occur in cold weather.
3.3.2.3 Fan Imbalance. A few systems are subjected to fan imbalance
conditions due to the buildup of sludge on the fan blades, the corrosion
of the fan blades, the erosion of the fan blades, and a variety of other
factors. The inspection should be terminated immediately whenever an
Inspector observes a severely vibrating fan. A responsible representative
of the facility should be notified once the inspector reaches a safe
location. Severely vibrating fans can disintegrate suddenly.
3.3.2.4 Sampling Liquors and Sludges. All liquor or sludge samples
necessary for Level 3 or Level 4 Inspections should be taken by the
facility personnel, not the inspector. Furthermore, the inspectors should
only ask responsible and experienced plant personnel to take the
samples. Eye injuries and chemical burns (in some cases) are possible if
the samples are taken incorrectly. Also, the liquor or sludge may contain
Infectious agents.
3.3.3 Dry Scrubbers
3.3.3.1 Inhalation Hazards. Poorly ventilated areas in the vicinity
of positive pressure dry scrubber absorbers, particulate control systems,
and/or ductwork should be avoided. There are a variety of inhalation
hazards associated with HWI's, including but not limited to asphyxiants,
toxic gases, toxic particulate, and, at facilities licensed for
radioactive wastes, radioactive materials.
Concentrations of these pollutants (particularly HC1) can exceed the
maximum allowable use levels of air-purifying respirators. Inspectors
must be able to recognize and avoid areas of potentially significant
exposure to fugitive emissions from the dry scrubbing system. A simple
flowchart that indicates the locations of all fans is a useful starting
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point 1n Identifying portions of the system that operate at positive
pressure.
3.3.3.2 Chemical and Eye Hazards. The strong alkalis used in dry
scrubbing have the potential to cause severe eye damage. While the
probability of eye contact and skin contact is relatively small for Agency
inspectors, it is nevertheless important to keep in mind the general first
aid procedures. These are briefly summarized below.
1. After eye contact, flushing should be started immediately;
2. Eyes should be flushed for 15 to 30 minutes;
3. After skin contact, all affected clothing should be removed, and
the Inspector should shower for a minimum of 15 minutes; and
4. Medical attention should be obtained in all situations.
During the routine inspection, agency personnel should note the
locations of any eye wash stations and showers. These are generally
located in the immediate vicinity of chemical handling areas. After the
first aid procedures are completed, it is especially important to get
qualified medical attention regardless of the presumed seriousness of the
exposure. All inspectors should have full first aid and safety training
before conducting field inspections of HWI's or any other type of air
pollution source.
3.3.4 Fabric Filters
Most fabric filters installed at HWI facilities likely will be
coupled with some sort of dry scrubber because of the concern with HC1 and
condensible metal emissions. However, at least one existing facility is
equipped with a stand-alone fabric filter. The information presented in
this section will generally be applicable in either of these cases. Where
there is differentiation between fabric filters' with and without an
upstream scrubber, these differences will be pointed out.
3.3.4.1 Hot Surfaces. Stand-alone fabric filters serving HWI's must
operate at high gas temperatures in excess of 300°F to avoid condensation
of the HC1 gas found in the gas stream. Even fabric filters located
downstream from a dry scrubbing system are expected to operate at
relatively high gas temperatures of 250° to 350°F. (These systems are not
yet typical at HWI facilities; the temperature range given is based on
typical municipal waste incineration systems.) Thus, uninsulated baghouse
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roofs can be a serious burn hazard. Unfortunately, it is important to
inspect this area of pulse jet fabric filters to identify possible air
infiltration problems and to check the diaphragm valves and the compressed
air pressure gauge.
3.3.4.2 Inhalation Hazards. Fugitive emissions from positive
pressure fabric filter systems can accumulate in poorly ventilated areas
around the baghouse. The inhalation hazards can include asphyxiants,
toxic gases/vapors, toxic particulate, and, at facilities licensed for
radioactive wastes, radioactive materials.
3.3.4.3 Opening Hatches. It is sometimes helpful to have plant
personnel open one or more hatches of fabric filter compartments which are
isolated for inspection. However, the discharge hopper hatches should not
be opened during the inspection because hot, free-flowing dust can be
released and cause severe burns. Opening of hopper hatches can also
create the potential for hopper fire if the combustible content of the ash
is high.
3.3.4.4 Flyash Storage and Handling. All materials collected by a
fabric filter should be considered hazardous. At HWI facilities
controlled with a stand-alone fabric filter, flyash may contain hazardous
levels of metals, dioxins/furans, acids, and, at poorly operated units,
infectious agents. At HWI facilities equipped with a dry scrubber
upstream from the fabric filter, the same hazards exist, except that the
possibility of exposure to acids is replaced by caustic exposure
hazards. These hazards should be considered during inspection of flyash
handling and disposal facilities, and skin contact and inhalation of
fugitive dust should be avoided.
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4.0 VISIBLE EMISSION OBSERVATION
The observation of the stack visible emissions from hospital waste
incinerators is an important part of the air compliance inspection.
Visible emission observations are important for two reasons. First, many
State regulations stipulate opacity limits or the construction/operating
permit likely will stipulate an opacity limit. Consequently, visual
observation of the emissions provides a direct means of establishing
compHance/noncompliance with a provision of the regulation.
Second, the presence of visible emissions provides an indication of a
combustion/control problem. The cause of the emissions can be further
investigated and evaluated to determine if a violation exists and to
determine what corrective action is warranted. For example, a detached
plume (i.e., a plume that forms in the atmosphere after exiting the stack)
at a hospital incinerator likely is caused by condensing hydrogen chloride
(HC1). A black plume is due to incomplete combustion of carbonaceous
matter. The possible causes for various plume appearances are further
discussed in Section 4.3.
Two primary methods of determining stack gas opacity are used. The
first method is visible observation of the plume at the point of
detachment from the stack by a qualified observer (i.e., the inspector)
per EPA Reference Method 9. The second method is an instrument method,
which employs a transmissometer that continuously monitors stack gas
opacity. Each of these methods is briefly discussed below.
4.1 EPA REFERENCE METHOD 9
The EPA Reference Method 9—-Visual Determination of the Opacity of
Emissions from Stationary Sources—is the EPA method for determining
opacity of visible emissions by a qualified observer. Method 9 involves
observations of a hospital waste incinerator stack plume at the point of
detachment and provides a simple means of assessing incinerator
performance. The only problem with application of the method to hospital
incinerators is that for incinerators controlled by wet scrubbers, the
combustion gas likely will be saturated with moisture and a condensed
water plume will be present. Although Method 9 may still be used for
observing opacity in such cases, application of the method is more
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difficult than in cases where the incinerator is controlled with a "dry"
control device.
Method 9 is published in 40 CFR Part 60, Appendix A; an inspector
must be certified and should be familiar with all aspects of the method.
The requirements of Method 9 are summarized in Table 4-1. A Method 9
visible emission form is presented in Appendix 0. Method 9 specifies that
the opacity readings taken by the observer are used to calculate the
average opacity for 6-m1nute intervals. Some State and local regulations
may specify other averaging periods or different data reduction methods
(I.e., maximum opacity limit never to be exceeded) for determining
compliance. Nonetheless, the method of observation is the same.
4.2 CONTINUOUS EMISSION MONITORING FOR OPACITY
Either State law or the construction/operating permit might require
that the facility continuously monitor the combustion gas opacity.
Obviously, the advantage of a continuous emission monitoring system (CEMS)
is that the opacity can be determined at all times during operation of the
Incinerator. The information provided by the CEMS can be used by the
operator to identify operating problems on a real-time basis; conse-
quently, immediate corrective action can be taken. The CEMS data records
also can be used by the regulatory agency to assess historical
performance.
A transmissometer is used to monitor stack gas opacity. The
operating principle of a transmissometer involves measurement of the
absorbance of a light beam across the stack or duct. Transmissometers use
a light source directed across the stack towards a detector, or reflector,
on the opposite side. The amount of light absorbed or scattered is a
function of the particles in the light path, path length (duct diameter),
and several other variables that are considered in the design and
installation. Figure 4-1 is a schematic of a dual-pass transmissometer
system. Additional detailed information on transmissometers is available
in Reference 1.
The EPA has promulgated performance specifications for opacity
monitoring systems (Performance Specification I—Specification and Test
Procedures for Opacity Continuous Emission Monitoring Systems in
Stationary Sources; 40 CFR Part 60, Appendix B). These specifications are
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TABLE 4-1. SUMMARY OF METHOD 9 REQUIREMENTS
Observer
1. Must be qualified (certified) by procedures established in Method 9
2. Certification valid for 6 months
Position of Observer
1. At sufficient distance to provide a clear view
2. Sun in 140° sector to observer's back
3. Line of vision approximately perpendicular to plume direction and to
longer axis of rectangular outlets
4. Line of sight does not pass through more than one plume where there
are multiple outlets
Field Records
1. Plant name
2. Emission location
3. Type of facility
4. Observer's name and affiliation
5. Sketch of observation position relative to source
6. Date
7. Data to be recorded both at start and end of observation period:
Time
- Estimated distance to source
Approximate wind direction and speed
Sky condition (presence and color of clouds)
Plume background
Observations
1. Read at point of greatest opacity where condensed water vapor is not
present
• For attached steam plumes, read at the point of greatest opacity
after the condensed water vapor has evaporated and record the
approximate distance from the outlet;
• For detached steam plumes, read at the outlet before water vapor
condenses
2. Observe the plume momentarily for a reading at 15-second intervals
(continued)
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TABLE 4-1. (continued)
Recording Observations
1. Record readings to nearest 5 percent opacity at 15-second intervals
2. Take a minimum of 24 readings
Data Reduction
1. Reduce the data by averaging each set of 24 consecutive readings
2. Sets nay consist of any 24 consecutive readings but may not overlap
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Retroreilector
aiurmhlv
Proeparator air inlet
Blower
Ambient
air
Blower
Figure 4-1. Typical transmissometer installation for measuring opacity.1
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applicable for opacity CEMS applied at sources regulated by new source
performance standards (NSPS). Table 4-2 presents a summary of these
performance specification requirements. Hospital incinerators do not fall
into this category, but typically, State regulations also will require
that a performance test be conducted at the time of initial installation
and startup. Typically, a transmissometer system will have a means of
automatically checking instrument calibration on a regular schedule (e.g.,
daily) by placing a filter of known light absorbance in the light path.
Calibration requirements for transmissometers subject to NSPS are
specified 1n 40 CFR 60.13; daily calibration checks are required.
Prior to the inspection, the inspector should review the source file
to determine the opacity monitoring requirements, if any, for the
facility. The calibration requirements and recordkeeping requirements
should be Identified. The results of the last performance specification
test or quality assurance audit should be reviewed.
Transmissometers are sophisticated electronic instruments;
consequently, evaluation of the performance of the monitor (e.g.,
calibration accuracy) 1s not easily assessed by the Inspector. However,
gross operational, maintenance, and recordkeeping problems can be
identified during an Inspection. If problems are suspected, a complete
performance audit of the system can be conducted at a later date by
qualified personnel. Performance audit procedures for opacity monitors
are presented and discussed in an EPA document entitled "Performance Audit
Procedures for Opacity Monitors" (Reference 2).
During the inspection, the inspector should:
1. Determine that the monitor is operating;
2. Review historical calibration records to assess calibration
problems;
3. Review the opacity data records to assess recordkeeping
procedures; and
4. Review historical data to assess frequency of excess emissions.
The inspector should locate the monitor and visually inspect its
condition including, for example, the operation of accessories such as
blowers designed to keep lenses clean. This initial visual inspection
will give the inspector a general idea of whether the monitor is well
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TABLE 4-2. PERFORMANCE SPECIFICATIONS FOR
OPACITY MONITORS
Parameter Specifications
Calibration errord <3 percent opacity
Response time <10 seconds
Conditioning periodb >168 hours
Operational test period^ >168 hours
Zero drift (24-hour)a <2 percent opacity
Calibration drift (24-hour)a <2 percent opacity
Data recorder resolution <0.5 percent opacity
Expressed as the sum of the absolute value of the mean
.and the absolute value of the confidence coefficient.
During the conditioning and operational test periods,
the CEMS must not require any corrective maintenance,
repair, replacement, or adjustment other than that
clearly specified as routine and required in the
operation and maintenance manuals.
Source: 40 CFR Part 60, Appendix B.
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maintained. The monitor data display/recorder should be located and the
following questions asked:
1. Is the monitor online and recording data?
2. Are any system failure warning lights illuminated?
3. Is the data recording system operating and does the strip chart
appear normal (e.g., values less than zero are not normal)?
4. Does the current indicated opacity level appear correct based
upon visual observation? For example, if the monitor indicates a steady
baseline reading of 0 percent opacity, but visual inspection indicates
excursions of up to 20 percent opacity, a problem exists.
The inspector should ask to review the most recent calibration data
to assure that:
1. Calibration frequency is at least that specified in the
regulations or construction/operating permit;
2. The value being used as the calibration value is the same as the
calibration level identified during the most recent performance test; if
not, an explanation of how the new calibration value was determined should
be available; and
3. Corrective action has been taken (i.e., the instrument has been
recalibrated) when calibration checks indicated the monitor was out of
calibration.
The inspector should review the opacity data records to determine:
1. If recordkeeping procedures are consistent with those required in
the regulations and or construction/operating permit (e.g., continuous
strip chart record on a real-time basis or data logger/recorder of
6 minute averages, etc.);
2. The frequency of excess emissions; and
3. Instrument availability.
Finally, the inspector should request to see the maintenance log for the
monitor (if required by the regulations or operating permit). The
maintenance log should be reviewed to determine the frequency of
maintenance and the presence of any major operational problems that are
recurring and are affecting instrument availability.
The identification of serious problems or deficiencies with the
opacity CEMS by the inspector indicates that a complete system/performance
audit of the CEMS should be considered.
4-8
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4.3 SPECIAL CONSIDERATIONS FOR OPACITY OBSERVATIONS AT HOSPITAL INCINERATORS
4.3.1 Stack Location
At some facilities, the incinerator is located on the roof. This
location may present an observer on the ground with a line of sight at an
extreme angle upward through the plume, possibly biasing opacity readings
high. Under these circumstances, it is preferable that the observer
determine opacity from an adjacent building or from the roof of the HWI
facility.
Because the incinerator may be located in a confined space, it may be
difficult to obtain an appropriate line of site that is in the proper
orientation with the sun and/or that is a sufficient distance away from
the source. Additionally, the stack may be shorter than the adjacent
building causing shadow and orientation problems.
4.3.2 Steam (Condensing Water Vapor) Plumes
At HWI facilities equipped with wet scrubbers, the plume typically
will be saturated with water and will contain condensed water vapor as it
leaves the stack (an attached steam plume). Under these circumstances,
the observer must read the plume's opacity at a point after the condensed
water vapor has dissipated. In most cases, such readings at an HWI
facility will not be meaningful because the plume will be diluted at the
point of observation.
At uncontrolled facilities and those equipped with a spray dryer/
fabric filter or stand-alone fabric filter, depending upon atmospheric
conditions (temperature and relative humidity), water vapor may condense
in the plume after it leaves the stack (a detached steam plume). Opacity
readings must be made in the section of the plume prior to this condensa-
tion. If other condensibles (e.g., HC1 or metals) are in the gas stream,
they will not be included in these opacity readings.
4.3.3 Evaluating Visible Emissions
Common opacity problems at hospital waste incinerators and their
typical causes are discussed below.
4.3.3.1 Dense Black Smoke. Dense black smoke is due to incomplete
combustion of carbonaceous material. The probable cause is insufficient
secondary chamber combustion air. Either the combustion air to the
secondary chamber is improperly set, or volatile matter is being generated
in excess of the incinerator's secondary chamber capacity.
4-9
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4.3.3.2 Detached White Plume. A detached hazy white plume is
probably caused by HC1 condensing in the cooling gas stream. This
situation cannot be controlled by modifying operation of the incinerator,
other than by decreasing the quantity of chlorine-containing wastes fed to
the incinerator.
4.3.3.3 Attached White Plume. An attached white plume indicates the
presence of submicron aerosols in the gas stream. Possible causes are
insufficient secondary combustion chamber temperature or the presence in
the waste of noncorabustible inorganic materials that volatilize and are
emitted to the atmosphere.
4.3.4 Fugitive Emissions
Fugitive emissions may be generated during ash handling or by the
action of wind on improperly stored ash at HWI facilities. These
emissions are typically intermittent and extremely variable, presenting
some difficulties with regard to characterization by the observer.
The observer should note the location of the fugitive emissions and,
as specifically as possible, quantify the duration and magnitude (e.g.,
fugitive emissions from ash removal door; constant emissions for
45 seconds; dense plume of approximately 75 percent opacity at 5 feet from
door; some flames also emitted).
4.4 REFERENCES FOR CHAPTER 4
1. Jahnke, J. A. APTI Course SI: 476A Transmissometer Systems—Operation
and Maintenance, and Advanced Course; EPA 450/2-84-004.
September 1984.
2. Entropy Environmentalists, Inc. 1983. Performance Audit Procedures
for Opacity Monitors. EPA 340/1-83-010.
4-10
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5.0 HOSPITAL INCINERATION SYSTEMS
5.1 INTRODUCTION
Incineration is the process by which combustible materials are
burned, producing combustion gases and noncombustible ash. The product
combustion gases are vented directly to the atmosphere or to the
atmosphere after treatment in an air pollution control device. The
noncombustible ash is removed from the incinerator system and is disposed,
usually in a landfill. Incineration provides the advantage of greatly
reducing the mass and volume of the waste. Typically, mass is reduced by
as much as 75 percent, and volume can be reduced by 95 percent or more.
This reduction substantially reduces transportation and disposal costs.
For infectious hospital wastes, another major objective of the
incineration process is the destruction of infectious organisms (path-
ogens) that may exist in the waste. The pathogens are destroyed by
exposure to the high temperatures which exist within the incinerator.
Incineration of hospital wastes also is attractive aesthetically because
it destroys organic components of the waste that the community often finds
objectionable when wastes are disposed of in landfills.
Two additional objectives achievable through proper operation of
hospital waste incinerators are minimizing the organic content in the
solid residue and controlling emissions to the atmosphere to acceptable
levels. Generally, tight control on organics in the ash, i.e., good
burnout, promotes waste reduction and pathogen destruction. Reduction of
atmospheric emissions of constituents that are potentially harmful to
human health and the environment is a prerequisite to acceptance of
hospital incineration as a feasible disposal alternative by the community.
5.2 TYPES OF HOSPITAL INCINERATOR SYSTEMS
The terminology used to describe hospital incinerators that has
evolved over the years is quite varied. Multiple names have been used for
the same basic types of incinerators, and much of the terminology does not
enhance precise definitions. Historically, however, most incinerators
were grouped into one of three types—"controlled air," "multiple
chamber," and "rotary kiln."
5-1
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Before the early 1960's, the incineration systems used were primarily
"multiple-chamber" systems designed and constructed according to Inciner-
ator Institute of America (IIA) (now defunct) incinerator standards. The
multiple-chamber incinerator has two or more combustion chambers. The two
traditional designs used for multiple-chamber incinerators are the "in-
line" hearth and "retort" hearth designs (these designs are further
explained 1n Section 5.2.2.4). These "multiple-chamber" systems were
designed to operate at high excess-air levels and hence are often referred
to as "excess-air" Incinerators.1 These units will be referred to as
"multiple-chamber Incinerators" throughout this manual. Multiple-chamber,
excess-air Incinerators are still in operation at some hospitals; their
use typically is for pathological wastes. Note that although the
singular term "multiple-chamber" Incinerator is often used to describe
this type of incinerator, in reality, the typical controlled-air modular
unit 1s also a multiple-chamber incinerator.
The Incineration technology that has been used most extensively for
hospital wastes over the last 20 years generally has been called
"controlled-air" Incineration. This technology is also called "starved-
air" combustion, "modular" combustion, and "pyrolytic" combustion. These
units will be referred to as "controlled-air incinerators" throughout this
manual. Most systems are prefabricated units transported to the site in
parts; hence the name "modular." The systems were called "controlled air"
or "starved air" because they operate with two chambers in series and the
primary chamber operates at substolchlometric conditions. Similar modular
"controlled-air" units which operate with excess-air levels in the primary
chamber are also manufactured and sold for combustion of municipal solid
waste, but are not as widely used.
Rotary kiln incineration systems have been widely used for hazardous
waste Incineration in the U.S. As with the other units, the rotary kiln
incinerator has two combustion chambers. The primary chamber is a hori-
zontal rotating kiln that operates with excess air. The waste is charged
to the elevated end of the kiln and moves through the kiln to the discharge
end at a rate determined by the angle of inclination and speed of rotation.
The exhaust gases exit the kiln to a fixed secondary chamber. There are a
few applications in the U.S. and Canada where the rotary kiln incineration
technology is being applied to hospital waste incineration.
5-2
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This historical grouping 1s of some assistance in understanding how
hospital Incinerators operate, but it is limited because it does not
address the complete combustion "system." Three parameters define the
hospital Incinerator system—the method of air supply and distribution,
the method of charging waste and moving waste through the system, and the
method of ash removal. In hospital incinerators, air supply/distribution
systems generally are one of two types, depending on whether the primary
chamber operates under substoichiometric (I.e., starved-air) or excess-air
conditions. Charging can be accomplished in one of three modes—batch,
Intermittent, or continuous. Ash is removed on a batch or a continuous
basis. Table 5-1 Identifies the major types of Incinerators that are
likely to be found at U.S. hospitals and characterizes them with respect
to the three key factors desribed above. Because air supply is
particularly important to achieving good combustion, the basic principles
of systems that operate at substoichiometric (starved-air) and excess-air
levels in the primary chamber are described in detail in the first
subsection below. The second subsection describes each of the types of
incinerators that are Identified in Table 5-1.
5.2.1 Principles of A1r Supply
5.2.1.1 Controlled-AIr Incineration. The principle of controlled-
air Incineration Involves sequential combustion operations carried out in
two separate chambers. Figure 5-1 Is a simplified schematic of an
incinerator that operates on controlled-air principles.
The primary chamber (sometimes referred to as the ignition chamber)
receives the waste, and the combustion process is begun in a
substoichiometric oxygen atmosphere. The amount of combustion air added
to the primary chamber is strictly regulated ("controlled"). The
combustion air usually is fed to the system as underfire air. Three
processes occur in the primary chamber. First, the moisture in the waste
is volatilized. Second, the volatile organic fraction of the waste is
vaporized, and the volatile gases are directed to the secondary chamber.
Third, the fixed carbon remaining in the waste is combusted.
The combustion gases containing the volatile combustible materials
from the primary chamber are directed to the secondary chamber (sometimes
referred to as the "combustion chamber"). There, the combustion air is
5-3
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regulated to provide an excess of oxygen and Is Introduced to the chamber
in such a manner as to produce turbulence to promote good mixing of the
combustion gases and combustion air. This gas/air mixture is burned,
usually at high temperatures. The burning of the combustion gases under
conditions of high temperature, excess oxygen, and turbulence promotes
complete combustion.
Figure 5-2 is a diagram showing the relationship between the
temperature 1n the primary and secondary chambers and the combustion air
level. This figure illustrates that the temperatures in the chambers can
be controlled by modulating the combustion air supply. Combustion control
for a controlled-air Incinerator is usually based on the temperature of
the primary (ignition) and secondary (combustion) chambers. Thermocouples
within each chamber are used to monitor temperatures continuously; the
combustion air rate to each chamber is adjusted to maintain the desired
temperatures. An alternative control mode is to monitor the oxygen level,
which 1s an indication of the excess-air level, within the combustion
chamber. The combustion air level is then set or modulated to maintain ;
the desired excess-air (oxygen) level. Systems operating under
"controlled-air" principles have varied degrees of combustion air
control. In many systems, the primary and secondary combustion systems
are automatically and continuously regulated or "modulated" to maintain
optimum combustion conditions despite varying waste composition and
characteristics (e.g., moisture content, volatile content, Btu value).5
In other systems (particularly batch or intermittent systems), the
combustion air level control is simplified and consists of switching the
combustion air rate from a "high" to a "low" level setting when
temperature setpoints are reached or at preset time intervals.
The controlled-air technique has several advantages over an excess
air mode. Limiting air in the primary chamber to below stolchlometric
conditions prevents rapid combustion and allows a quiescent condition to
exist within the chamber. This quiescent condition minimizes the
entrainment of particulate matter in the combustion gases which ultimately
are emitted to the atmosphere. High temperatures can be maintained in a
turbulent condition with excess oxygen in the secondary chamber to assure
complete combustion of the volatile gases emitted from the primary
5-6
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TEMPERATURE
PRIMARY +
CHAMBER OPERATING
RANGE
MAXIMUM
TEMPERATURE
SECONDARY
CHAMBER OPERATING
RANGE
DEFICIENT AIR
I
EXCESS AIR
PERCENT EXCESS AIR
Figure 5-2. Control of temperature as a function of excess air.'
5-7
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chamber. The temperature of the secondary chamber can be maintained in
the desired range (hot enough for complete combustion but not so hot to
cause refractory damage) by separately controlling the excess-air level in
the secondary chamber; as the excess-air level is increased, the
temperature decreases. Additionally, control of the primary chamber
combustion air to below stoichiometric levels maintains primary chamber
temperatures below the melting and fusion temperatures of most metals,
glass, and other noncombustibles, thereby minimizing slagging and clinker
formation.
For controlled-a1r combustion, the capacity of the secondary chamber
dictates (I.e., limits) the burning or charging rate. The secondary
chamber must have a volume such that the volatile gases, as they are
released from the primary chamber, are retained in the chamber for
sufficient time and at sufficient excess oxygen levels to ensure their
complete combustion. The volatile gases' retention times may range from
less than % second to more than 3 seconds. In order to maintain the
designed retention time, waste must be charged at the designed rate; >
overcharging can cause excessive primary chamber temperatures, high
combustion gas velocities, and shorter retention times, while
undercharging can cause lower primary chamber temperatures, lower
combustion gas velocities, and longer retention times.
5.2.1.2 Multiple-Chamber Incineration. The significant difference
between multiple-chamber incineration and controlled-air incineration is
that the primary chamber in the excess air unit is operated with above
stoichiometric air levels. The waste is dried, ignited, and combusted in
the primary chamber. Moisture and uncombusted volatile components pass
out of the primary chamber and through a flame port into the secondary
chamber. Secondary combustion air is added through the flame port and is
mixed with the volatile components in the secondary chamber where
combustion is completed. Multiple-chamber incinerators are designed for
surface combustion of the waste which is achieved by predominant use of
overfire combustion air and by limiting the amount of underfire air.
Multiple-chamber, excess-air incinerators operate with an overall excess-
air range of 300 to 600 percent.7 In older units, combustion air
typically was provided by natural draft via manually adjusted dampers and
5-8
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air in-leakage through charging or ash removal doors. Newer multiple-
chamber incinerators often use forced draft combustion air blowers to
provide the combustion air to the combustion chambers.
Because of the predominant use of overfire air, high excess air rate,
and surface combustion, turbulence and gas velocities are high in the
primary chamber. These conditions result in relatively high particulate
generation and entrainment. Therefore, multiple-chamber units have higher
particulate emission rates than controlled-air units.
5.2.2 Hospital Incinerator Descriptions
5.2.2.1 Batch/Control!ed-Air Incinerators. The least complex
hospital Incinerators are the batch/controlled-air units. The operation
of these units is relatively simple in that the incinerator is charged
with a "batch" of waste, the waste is incinerated, the incinerator is
cooled, and the ash is removed through the charging door; the cycle is
then repeated. (For this manual, the term "batch feed" is used to refer
to an incinerator that is loaded with one batch of waste during the
combustion cycle; the term "intermittent duty" is used to refer to units ;
where multiple charges are made.) Incinerators designed for this type of
operation range in capacity from about 50 to 500 Ib/h. In the smaller
sizes, the combustion chambers are often vertically oriented with the
primary and secondary chambers combined within a single casing.
Figure 5-3 is a schematic of a smaller controlled-air incinerator intended
for batch operation. This unit's combustion chambers are rectangular in
design and are contained within the same casing.
Batch/controlled-air units can be loaded manually or mechanically.
For the smaller units up to about 300 Ib/h, manual waste feed charging
typically is used. Manual loading involves having the operator load the
waste directly to the primary chamber without any mechanical assistance.
Typically, for a batch-type unit, one loading cycle per day is used. The
incinerator is manually loaded; the incinerator is sealed; and the
incineration cycle is then continued through burndown, cooldown, and ash
removal without any additional charging. Ash is removed manually at the
end of the cycle by raking or shoveling the ash from the primary chamber
through the charging door.
5-9
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5.2.2.2 Intermittent/Controlled-Air Incinerators. When mechanical
feeders are employed, the charging procedures of an incinerator that could
operate in batch mode often are varied to include multiple charges
(batches) during the 12 to 14 hour operating period before final burndown/
cooldown is initiated. These intermittent units typically operate in the
50 to 1,000 Ib/h range. The intermittent charging procedure allows the
dally charge to the incinerator to be divided into a number of smaller
charges that can be introduced over the combustion cycle. Consequently, a
more uniform gas stream is fed to the secondary chamber, and complete
burnout of the residue in the primary chamber can be achieved more
easily. Figure 5-4 is a drawing of a small incinerator which is intended
for intermittent operation when fitted with the proper manual or automatic
charging system to assure operator safety and limit air in-leakage.
A typical daily operating cycle for a controlled-air batch type
incinerator is as follows:
Operating step Typical duration
/
1. Cleanout of ash from previous day 15 to 30 minutes
2. Preheat of incinerator 15 to 60 minutes
3. Waste loading/combustion Up to 14 hours
4. Burndown 2 to 4 hours
5. Cooldown 5 to 8 hours
For intermittent-duty operation, the daily combustion cycle of the
incinerator is limited to about a 12- to 14-hour period. The remainder of
the 24-hour period is required for burndown, cooldown, ash cleanout, and
preheat.
For units in the 300 to 500 Ib/h range, mechanical waste feed systems
are often employed, and for units above 500 Ib/h, mechanical waste feed
systems are normally employed, 'he typical mechanical waste feed system
is a hopper ram assembly. In a mechanical hopper/ram feed system, waste
is manually placed into a charging hopper, and the hopper cover is
closed. A fire door isolating the hopper from the incinerator opens, and
the ram moves forward to push the waste into the incinerator. The ram
reverses to a location behind the fire door. After the fire door closes,
the ram retracts to the starting position and is ready to accept another
charge. Water sprays typically are located just behind the fire door and
5-11
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PAM flEVEBSES TO CLEAfl PISE DOOR
STEM
RAM RETURNS TO START
Figure 5-4. Operating sequence of a waste charging hopper/ram system.
5-12
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are used to cool the ram prior to retraction in order to prevent ignition
of the waste by the ram in the hopper/ram assembly. The entire charging
sequence is normally timed and controlled by an automatic sequence. For
batch type incinerators, the sequence would be set up to be manually
started by the operator. Figure 5-5 schematically presents the charging
sequence of a mechanical ram charging system.
Mechanical loading systems have several advantages. First, they
provide added safety to the operating personnel by preventing heat,
flames, and combustion products from escaping the incinerator during
charging. Second, they limit ambient air infiltration into the
incinerator; ambient air Infiltration works against the controlled-air
combustion principal of controlling combustion rate by strictly
controlling the quantity of available combustion air. Third, they enable
incinerators to be safely charged with smaller batches of waste at
regulated time intervals.
Note that even w-ith intermittent-duty incinerators, a limiting factor
for the incinerator operations is ash removal. As with the batch-operated
units, the waste loading/combustion cycle must stop, and the incinerator
must pass through burndown and cooldown cycles, before the incinerator can
be opened for daily ash removal. The ash usually is manually removed by
raking and/or shoveling from the primary chamber. Consequently, a major
improvement in operations can be achieved by using continuous or
intermittent ash removal as described in the subsection below.
5.2.2.3 Cont1nuous/Contro11ed-Air Incinerators. Controlled-air
units intended for continuous operation are available in the 500 to
3,000 Ib/h operating range. Continuous/controlled-air units operate
according to the controlled-air principles of the systems described
earlier. However, continuous operation or combustion requires a mechanism
for automatically removing ash from the incinerator hearth. The ash must
be moved across the hearth, collected, and removed from the combustion
chamber. Continuous ash removal while the incinerator is operating
removes the requirement for burndown and cooldown cycles.
Continuous-operation units typically will have mechanical waste
feeding systems. For large continuous-operation units, the charging
sequence may be fully automatic. The incinerator then can be
5-13
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STACK
CHARGING
DOOR
SECONDARY CHAMBER
SECONDARY BURNER
PRIMARY CHAMBER
IGNITION BURNER
Figure 5-5. Intermittent/controlled-air incinerator with^vertical
primary chamber and horizontal secondary chamber.
5-14
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automatically charged with relatively small batches (in relation to the
primary chamber capacity) at frequent, regulated time intervals. The use
of frequent, small charges promotes relatively stable combustion
conditions and approximates steady-state operation. For large systems,
the mechanical charging system may include waste loading devices such as
cart dumpers, which automatically lift and dump the contents of carts,
which are used to collect and contain the waste, into the charge
hoppers. Use of these loading devices reduces the operators need to
handle Infectious waste and, consequently, further improves worker safety.
For smaller units, the mechanical charging ram 1s sometimes used to
move the ash across the hearth. As a new load of waste is pushed into the
incinerator, the previous load is pushed forward. Each subsequent load
has the same effect of moving the waste across the hearth. The waste
should be fully reduced to ash by the time it reaches the end of the
hearth. For larger systems, one or more special ash rams are provided to
move the waste across the hearth.
Typically, when the ash reaches the end of the hearth, it drops off .<
into a discharge chute. One of two methods for collecting ash is usually
used. The ash can be discharged directly into an ash container positioned
within an air-sealed chamber. When the container is full, it 1s removed
fro» the chamber and replaced with an empty ash container. The second
method 1s for the ash to be discharged into a water pit. The water bath
quenches the ash, and it also forms an air seal with the incinerator. A
mechanical device, either a rake or a conveyor, is used to remove the ash
from the quench pit intermittently or continuously. The excess water is
allowed to drain from the ash as it is removed from the pit, and the
wetted ash is discharged into a container for transport to a landfill.
Figure 5-6 is a drawing of a continuous-operation controlled-air unit with
automatic mechanical ash removal and a mechanical hopper/ram charging
assembly.
5.2.2.4 Multiple-Chamber Incinerators. Two traditional designs that
are used for multiple-chamber incinerators are the "in-line" hearth and
"retort" hearth. Figure 5-7 depicts the retort design multiple-chamber
incinerator. In the retort design, the combustion gases turn in the
vertical direction (upward and downward) as in the in-line incinerator,
5-15
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Figure 5-6. Schematic of a continuous operation controlled-air
Incinerator with mechanical charging and ash removal.
5-16
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but also turn sideways as they flow through the Incinerator. Because the
secondary chamber is adjacent to the primary chamber (they share a wall)
and the gases turn in the shape of a U, the design of the incinerator is
more compact. Figure 5-8 depicts the in-line hearth design. For the in-
line hearth, flow of combustion gases is straight through the incinerator
with turns in the vertical direction only (as depicted by the arrows in
Figure 5-8). The retort design performs more efficiently than the in-line
design 1n the capacity range of less than 750 Ib/h. In-Hne incinerators
perform better in the capacity range greater than 750 Ib/h. The retort
design more typically 1s used in hospital waste applications.
Multiple-chamber Incinerators may have fixed hearths or grates or a
combination of the two 1n the primary chamber. The use of grates for a
system incinerating infectious waste is not recommended because liquids,
sharps, and small partially combusted items can fall through the grates
prior to complete combustion or sterilization.
Like the controlled-air unit, combustion in the multiple-chamber
incinerator occurs in two combustion chambers, but the primary chamber
operates with excess air. Ignition of the waste (initially by a primary
burner), volatilization of moisture, vaporization of volatile matter, and
combustion of the fixed carbon occur 1n the primary chamber. The
combustion air for these processes is controlled on old units by natural
draft, manually adjusted dampers, or by forced draft combustion air
blowers on newer units. The combustion gases containing the volatiles
exit the primary chamber through a flame port into a mixing chamber and
then pass into the secondary combustion chamber. Secondary combustion air
is added at the flame port and is mixed with the combustion gases in the
mixing chamber. A secondary burner is provided in the mixing chamber to
maintain adequate temperatures for complete combustion as the gases pass
into and through the secondary combustion chamber.
Today, new multiple-chamber, excess-air Incinerators are not widely
installed for the destruction of hospital wastes for the following
reasons. First, operating in the surface-combustion excess-air mode
results in fly ash carryover which causes excessive particulate matter
emissions. Second, operating with high levels of excess air can require
high auxiliary fuel usage to maintain secondary combustion chamber
5-18
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CHARGING DOOR
*ITH OVEftflftE
1IR PORT
SECONDARY
COMBUSTION
CHAMBER
LOCATION OF
SECONDARY
BUHNER
GiJATES
•CIEANOUT ODORS IITH
UNOERGRATE AIR PORTS
Ml I INS CHAMBER
CURTAIN
IAU PORT
Figure 5-8. In-line excess air incinerator.
13
5-19
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temperatures. Third, use of manually adjusted natural draft combustion
air dampers does not provide the level of control desirable for assuring
complete combustion of the variable waste constituents found in hospital
wastes, and good burnout can be more difficult to achieve.
Multiple-chamber incinerators frequently are designed and used
specifically for incinerating pathological ("Type 4" anatomical) wastes.
Pathological waste has a high moisture content and may contain liquids;
consequently, a pathological waste incinerator always will be designed
with a fixed hearth. A raised Up at the charging door often is designed
into the hearth to prevent liquids from spilling out the door during
charging. Because the heating value of pathological waste is low and is
not sufficient to sustain combustion, the auxiliary burner(s) provided in
the primary chamber of pathological incinerators are designed for
continuous operation and with sufficient capacity to provide the total
heat Input required to complete combustion.
5.2.2.5 Rotary Kiln Incinerators.1** Like other incinerator types,
rotary kiln Incineration consists of a primary chamber in which waste 1s >
heated and volatilized and a secondary chamber in which combustion of the
volatile fraction 1s completed. In this case, however, the primary
chamber consists of a horizontal, rotating kiln. The kiln is inclined
slightly so that the waste material migrates from the waste charging end
to the ash discharge end as the kiln rotates. The waste migration, or
throughput, rate 1s controlled by the rate of rotation and the angle of
incline, or rake, of the kiln. Air 1s Injected into the primary chamber
and mixes with the waste as it rotates through the kiln. A primary
chamber burner is generally present both for heat-up purposes and to
maintain desired temperatures. Figure 5-9 is a schematic of a rotary kiln
with a mechanical auger feeder system.
Volatlles and combustion gases from the primary chamber pass to the
secondary chamber where combustion is completed by the addition of air
together with the high temperatures maintained by a secondary burner. Due
to the turbulent motion of the waste 1n the lower primary chamber,
particle entrainment in the flue gases is higher for rotary kiln
incinerators than for controlled-air or excess air Incinerators.
5-20
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Figure 5-9. Drawing for rotary kiln Incinerator.
is
5-21
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5.3 AIR POLLUTION CONTROL SYSTEMS
Add-on pollution control systems may be required to meet the air
pollution limits of some States. Pollutants of concern include
partial!ate matter, metals, toxic organics, acid gases and radionuclides.
The pollution control systems which might be used to control hospital
waste incinerator emissions include wet scrubbers, dry scrubbers, and
fabric filters. These systems are described briefly in the following
subsections.
5.3.1 Wet Scrubbers
Venturi and packed-bed scrubbers are the most common types of wet
scrubber systems used on hospital incinerators. Venturi scrubbers are
used primarily for partlculate matter control and packed-bed scrubbers are
used primarily for acid gas control. However, both types of systems
achieve some degree of control for both particulate matter and acid gases.
Most of the scrubber systems recently installed or currently being
installed on hospital incinerators consist of a variable throat venturi
followed by a packed-bed scrubber and mist eliminator. These systems >••
operate at a constant pressure drop 1n the range of 20 to 40 inches of
water column (1n. w.c.), depending on performance or permit condition
requirements. The variable throat venturi design accommodates varying gas
flow rates while maintaining a constant pressure drop by changing the
venturi throat area. A pH controller system, including a pH electrode and
transmitter, adjusts the flow of a caustic solution (sodium hydroxide or
sodium carbonate) to the scrubber system to accommodate varying acid gas
concentrations and gas flow rates. Typical performance parameters for
this system are summarized in Table 5-2.
Operation and maintenance problems associated with wet scrubbers
include fan imbalance, nozzle wear or plugging, pump seal leaks, pH
controller drifts, pH electrode fouling, and wet-dry interface buildup.
Specific problems associated with HWI's stem from batch loading and
nonsteady state combustion conditions that result in varying gas flow
rates, gas temperatures, particle size distribution, particle
concentration, and acid gas concentrations.
5.3.1.1 Venturi Scrubber Operating Principles. A venturi scrubber
consists of a liquid sprayed upstream from a vessel containing converging
5-22
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TABLE 5-2. WET SCRUBBER PERFORMANCE PARAMETERS
Hospital Waste Incinerators
Parameter
Typical range
Units of measure
Venturi scrubbers
Pressure drop
Liquid feed rate
Liquid to gas rate
Liquid feed pressure
Turbidity
Gas flow rate
Packed-bed scrubbers
Pressure drop
Liquid feed rate
Liquid feed pH
Liquid to gas rate
Liquid feed pressure
Gas flow rate
20 to 50
>35
7 to 10
20 to .60
1 to 10
>5,000
1-3
>5
5.5 to 10
1-6
20 to 60
>5,000
in. w.c.
gal/rain
gal/Macf
psi
Percent suspended solids
acfra
in. w.c.
gal/rain
PH
gal/Macf
psi
acfra
5-23
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and diverging cross sectional areas as illustrated in Figure 5-10. The
portion of the venturl that has the smallest cross sectional area and
consequently the maximum gas velocity is commonly referred to as the
throat. The throat can be circular as shown in Figure 5-10 or rectangular
as shown in Figure 5-11. Liquid droplets serve as the particle collection
media and can be created by two different methods. The most common method
is to allow the shearing action of the high gas velocity in the throat to
atomize the liquid 1n the droplets. The other method is to use spray
nozzles to atomize the liquid by supplying high pressure liquid through
small orifices.
Impactlon is the primary means for collection of particles in venturi
scrubbers. To attain high collection efficiency, venturi scrubbers need
to achieve gas velocities in the throat in the range of 10,000 to 40,000
feet per minute. As the gas stream approaches the venturi throat, the gas
velocity and turbulence increases. These high gas velocities atomize the
water droplets and create the relative velocity differential between the
gas and the droplets to effect particle-droplet collision. The
effectiveness of a venturi scrubber is related to the square of the
particle diameter and to the difference in velocities of the liquor
droplets and the particles.
The performance of a venturi scrubber is strongly affected by the
size distribution of the partlculate matter. For particles greater than 1
to 2 urn. in diameter, impaction is so effective that penetration (emis-
sions) is quite low. However, penetration of smaller particles, such as
the particles in the 0.1 to 0.5 urn range is very high. Unfortunately,
hospital waste incinerators can generate substantial quantities of partic-
ulate matter in this submicron range. The small particle size distribu-
tion is typical for fuel combustion sources and results from the condensa-
tion of partially combusted organic compounds and the condensation of
metallic vapors.
Collection efficiency in a venturi scrubber system increases as the
static pressure drop increases. The static pressure drop is a measure of
the total amount of energy used in the scrubber to accelerate the gas
stream, to atomize the liquor droplets, and to overcome friction. The
pressure drop across the venturi is a function of the gas velocity and
5-24
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Converging
section
L Throat
Diverging
section
Figure 5-10. Venturl configuration.
16
5-25
-------
Liquid inlet
Figure 5-11. Spray ventuH with rectangular throat.17
5-26
-------
I1qu1d/gas ratio and in practice acts as a surrogate measure for gas
velocity.
Other variables that are important to venturi scrubber performance
are the liquid surface tension and liquid turbidity. If surface tension
is too high, some small particles which impact on the water droplet will
"bounce" off and not be captured. High surface tension also has an
adverse impact on droplet formation. High liquid turbidity, or high
suspended solids content, will cause erosion and abrasion of the venturi
section and ultimately lead to reduced performance of the system.
Most venturi scrubbers are designed to operate at liquid-to-gas (L/G)
ratios between 7 and 10 gallons per thousand actual cubic feet
(gal/Macf). At L/G ratios less than 3 gal/Macf, there is an inadequate
liquid supply to completely cover the venturi throat. At the other
extreme, L/G ratios above 10 gal/Macf are seldom justified because they do
not increase performance but do increase operating costs.
A list of the major components of commercial scrubber systems is
provided below.
1. Venturi section;
2. Spray nozzles;
3. Liquor treatment equipment;
4. Gas stream demister;
5. Liquor recirculation tanks, pumps, and piping
6. Alkaline addition equipment;
7. Fans, dampers, and bypass stacks; and
8. Controllers for venturi throat area, caustic feed, make up water,
and emergency water quench for temperature excursions.
5.3.1.2 Venturi Scrubber Operating Problems. A problem can be caused
by the adjustable throat being opened too far, and the result is a
reduction in pressure drop. Reduced pressure drop levels can also be
caused by a loss or reduction in the scrubber liquid supply. The liquid
flow rate will drop when there is pluggage in the nozzles, pipes, or
flowmeters, causing the pressure drop to decrease and the gas flow rate to
increase. Pump failure, or cavitation of a pump due to a low liquid level
in the recirculation tank, can also be responsible for a loss or reduction
in the liquid supply. These problems are identifiable from routine record
keeping and inspection, and can be readily resolved by maintenance.
5-27
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The venturl throat can be damaged by erosion or abrasion caused by a
high level of suspended solids in the recirculated scrubbing liquid.
Reducing the suspended solids by increasing the blowdown (water makeup)
rate in the system will help solve erosion problems.
Another common problem with venturi scrubbers is a solids buildup at
the wet-dry interface. The wet-dry interface is the transition region
where the gas stream changes from an unsaturated to a saturated
condition. As the hot gas stream comes into contact with the scrubbing
liquid and becomes cooled and saturated, there is a tendency for the
suspended particulate to accumulate on the walls. Scrubber design can
help reduce this solids buildup, but gradual accumulation of deposits will
occur. Routine maintenance to remove this buildup is typically the only
solution. Sometimes a reduction in the suspended solids content will
reduce the rate of the buildup, but routine maintenance will still be
required at less frequent intervals.
5.3.1.3 Packed-Bed Scrubber Operating Principles. A packed-bed
scrubber generally 1s used for add gas removal. The large liquor surface/
area created as the liquor gradually passes over the packing material
favors gas diffusion and absorption. Packed-bed scrubbers are not
effective as stand-alone scrubbers for collection of fine particulate
matter (less than 2.5 um) since the gas velocity through the bed(s) is
relatively low. However, packed beds are effective for the removal of
particle-laden droplets or charged particles when used as a downstream
collector behind a venturi or electrostatically-enhanced wet scrubber.
Packed beds can be either vertical or horizontal. Figure 5-12
illustrates a vertically oriented scrubber. Regardless of the orientation
of the bed, the liquor is sprayed from the top and flows downward through
the bed. Proper liquor distribution is important for efficient removal of
gases.
Absorption is the primary means of collection of acid gases in
packed-bed scrubbers. The effectiveness of absorption in packed beds is
related to the uniformity of the gas velocity distribution, the surface
area of the packing material, the amount and uniform distribution of
scrubber liquid, and the pH and turbidity of the scrubbing liquid.
5-28
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SCTU88INQ UQUIO
IN
PACKING
DIRTY SAS
IN
CLEAN GAS
OUT
CLEAR UQUIO WASH
OEMISTER
HOLD DOWN PLATE
INTERMEDIATE PACKING
SUPPORT PLATES AND / OH
UQUIO RCOISTRIBUTOR
PACK:NO SUPPORT PLATE
Figure 5-12. Vertically oriented packed-bed scrubber.
5-29
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Gas absorption is effected by the extensive liquid surface contacted
by the gas stream as the liquid flows downward over the packing
material. A variety of available packing materials offer a large exposed
surface area to facilitate contact with and absorption of acid gases. The
packing materials range in size from 0.5 to 3 in. and are randomly
oriented in the bed.
Typically, sodium hydroxide (NaOH) or occasionally sodium carbonate
(Na2C03) is used with water to neutralize the absorbed acid gases in a
packed-bed scrubber. These two soluble alkali materials are preferred
because they minimize the possibility of scale formation in the nozzles,
pump, and piping. For the typical system using NaOH as the neutralizing
agent, the HC1 and S02 collected in the scrubber react with NaOH to
produce sodium chloride (NaCl) and sodium sulfite (Na2S03) in an aqueous
solution.
One of the major problems with these scrubbers is the accumulation of
solids at the entry to the bed and within the bed. The dissolved and sus-
pended solids levels in the liquor must be monitored carefully to maintain^"
performance.
5.3.1.4 Packed Bed Operating Problems. One common problem is
partial or complete pluggage of the bed due to deposition of the collected
solids and/or precipitation of solids formed by reaction of the
neutralizing agent with acid gases. Another problem is settling of the
packing material which leaves an opening at the top of the packed
section. Both of these situations reduce the performance of the scrubber
by disturbing the uniform flow of the liquid and gas streams.
Another common problem occurs when the pH of the scrubbing liquid
routinely falls outside the normal range of 5.5 to 10. Corrosion and
erosion of the packed bed vessel, ducting, and piping can occur when the
scrubber liquid is not in the range for which the system was designed.
5.3.2 Dry Scrubbers
Dry scrubbers utilize absorption and adsorption for the removal of
sulfur dioxide, hydrogen chloride, hydrogen fluoride, and other acid
gases. Some adsorption of vapor state organic compounds and metallic
compounds also occurs in some dry scrubber applications. This relatively
new control technology is presently in use on pulverized coal-fired
5-30
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boilers and municipal waste incinerators. Dry scrubbers are anticipated
to be used on some large hospital waste incinerators in the near future.
Because there are no current dry scrubber applications on hospital waste
incinerators, information available on municipal waste incinerators will
be transferred and presented in this report. Much of the presently
available information applicable to municipal waste incinerators has been
drawn from European installations operating for the last 3 to 5 years and
U.S. installations operating for the last 1 to 2 years. Changes and
refinements in municipal and hospital waste incinerator dry scrubbers
should be anticipated as more experience with these systems is gained.
5.3.2.1 Components and Operating Principles of Dry Scrubber
Systems. There is considerable diversity in the variety of processes
which are collectively termed dry scrubbing. This is partially because
the technology is relatively new and is still evolving. The diversity
also exists because of the differing control requirements. For purposes
of this field inspection manual, the various dry scrubbing techniques have
been grouped into three major categories: (1) spray dryer absorbers,
(2) dry injection adsorption systems, and (3) combination spray dryer and
dry injection systems. Specific types of dry scrubbing processes within
each group are listed below. Alternative terms for these categories used
in some publications are shown in parentheses.
1. Spray dryer absorption (semiwet)
• Rotary atomizer spray dryer systems
• Air atomizing nozzle spray dryer systems
2. Dry injection adsorption (dry)
• Dry injection without recycle
• Dry injection with recycle (sometimes termed circulating fluid
bed adsorption)
3. Combination spray dryer and dry injection (semiwet/dry)
Simplified block diagrams of the three major types of dry scrubbing
systems are presented in Figures 5-13, 5-14, and 5-15. The main differ-
ences between the various systems are the physical form of the alkaline
reagent and the design of the vessel used for contacting the acid gas
laden stream. The alkaline feed requirements are much higher for the dry
injection adsorption than the other two categories. Conversely, the spray
5-31
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Pump
Figure 5-13. Components of a spray dryer absorber system
(semiwet process).
5-32
-------
Figure 5-14. Components of a dry injection absorption system
(dry process).
5-33
-------
Figure 5-15. Components of a combination spray dryer and dry injection
absorption system (semiwet/dry process).
5-34
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dryer absorption and combination systems are much more complicated. It
should be noted that the participate control devices shown on the right
hand side of the figures are generally fabric filters or electrostatic
precipitators. It also is possible that one and two stage wet scrubbing
systems will be used in certain cases.
The pollutant removal efficiencies for all three categories of dry
scrubbing systems appear to be very high. In most cases, outlet gas
stream continuous monitors provide a direct indication of the system
performance.
5.3.2.1.1 Spray dryer absorbers. In this type of dry scrubbing
system, the alkaline reagent is prepared as a slurry containing 5 to
20 percent by weight solids. " This slurry is atomized in a large
absorber vessel having a residence time of 6 to 20 seconds.23*21*
There are two main ways of atomization: (1) rotary atomizers and
(2) air atomizing nozzles. There is generally only one rotary atomizer.
However, a few applications have as many as three rotary atomizers.
The shape of the scrubber vessel must be different for the two types
of atomizers to take into account the differences in the slurry spray
pattern and the time required for droplet evaporation. The length-to-
dlaaeter ratio for rotary atomizers is much smaller than that for absorber
vessels using air atomizing nozzles.
It is important that all of the slurry droplets evaporate to dryness
prior to approaching the absorber vessel side walls and prior to exiting
the absorber with the gas streai. Accumulations of material on the side
walls or at the bottom of the absorber would necessitate an outage since
these deposits would further impede drying. Proper drying of the slurry
is achieved by the generation of small slurry droplets, by proper flue gas
contact, and by use of moderately hot flue gases.
Drying that is too rapid can reduce pollutant collection efficiency
since the primary removal mechanism is absorption into the droplets.
There must be sufficient contact time for the absorption. For this
reason, spray dryer absorbers are operated with exit gas temperatures 90°
to 180°F above the saturation temperature."5"27 The absorber exit gas
tenperatures are monitored to ensure proper approach-to-saturation which
is simply the difference between the wet bulb and dry bulb temperature
monitors at the outlet of the absorber vessel.
5-35
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In rotary atomizers, a thin film of slurry is fed to the top of the
atomizer disk as 1t rotates at speeds of 10,000 to 17,000 revolutions per
minute. These atomizers generate very small slurry droplets having
diameters in the range of 100 microns. The spray pattern is inherently
broad due to the geometry of the disk.
High pressure air is used to provide the physical energy required for
droplet formation in nozzle type atomizers. The typical air pressures are
70 to 90 pslg. Slurry droplets in the range of 70 to 200 microns are
generated. This type of atomizer generally can operate over wider
variations of the gas flow rate than can be used in a rotary atomizer.
However,-the nozzle atomizer does not have the slurry feed turndown
capability of the rotary atomizer. For these reasons, different
approaches must be taken when operating at varying system loads.
The alkaline material generally purchased for use in a spray dryer
absorber is pebble lime. This material must be slaked in order to prepare
a reactive slurry for absorption of acid gases. Slaking is the addition
of water to convert calcium oxide to calcium hydroxide. Proper slaking >
conditions are important to ensure that the resulting calcium hydroxide
slurry has the proper particle size distribution and that no coating of
the particles has occurred due to the precipitation of contaminants in the
slaking water.
Some of the important operating parameters of the lime slaker are the
quality of the slaking water, the feed rate of lime, and the slurry exit
temperature. However, it is difficult to relate present operating
conditions or shifts from baseline operating conditions to possible
changes in the absorption characteristics of the dry scrubber system. A
variety of subtle changes in the slaker can affect the reactivity of the
liquor produced.
One of the problems which has been reported for spray dryer absorber
type systems is the pluggage of the slurry feed line to the atomizer.
Scaling of the line can be severe due to the very high pH of this
liquor. The flow rate of the liquor to the atomizer is usually monitored
by a magnetic flow meter. However, this instrument also is vulnerable to
scaling since the flow sensing elements are on the inside surface of the
pipe. To minimize the pluggage problems, the lines must be well sloped
5-36
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and include the capability for flushing of the lines immediately after
outages. Also, there should not be abrupt line changes, sharp bends, or
adjacent high temperature equipment. During the inspection, it is
essentially impossible to identify emerging slurry line problems.
Recycle of the sol Ids collected in the absorber vessel is important
in most systems. It Increases the solIds content of the slurry feed to
the atomizer and thereby Improves the drying of the droplets. Recycle
also maximizes reagent utilization. The rate of solids recycle is
monitored on a continuous basis. The rest of the spent absorbent
typically 1s sent to a landfill.
5.3.2.1.2 Dry injection adsorption systems. This type of dry
scrubber uses finely divided calcium hydroxide for the adsorption of acid
gases. The reagent feed has particle sizes which are 90 percent by weight
2 8
through 325 mesh screens. This is approximately the consistency of
talcum powder. This size is important to ensure that there is adequate
calcium hydroxide surface area for high efficiency pollutant removal.
Proper particle sizes are maintained by transporting the lime to the
dry scrubber system by means of a positive pressure pneumatic conveyor.
This pneumatic conveyor provides the Initial fluldlzation necessary to
break up any clumps of reagent which have formed during storage. The air
flow rate 1n the pneumatic conveyor is kept at a constant level regardless
of system load in order to ensure proper particle sizes.
Fluid1zat1on is completed when the calcium hydroxide is injected
counter-currently Into the gas stream. A venturi section is used for the
contactor due to the turbulent action available for mixing the gas stream
and reagent. The gas stream containing the entrained calcium hydroxide
particles and fly ash is then vented to a fabric filter.
Adsorption of acid gases and organic compounds (if present) occurs
primarily while the gas stream passes through the dust cake (composed of
calcium hydroxide and fly ash) on the surface of the filter bags.
Pollutant removal efficiency is dependent on the reagent particle size
range, on the adequacy of dust cake formation, and on the quantity of
reagent injected.
The calcium hydroxide feed rate for dry injection systems is three to
four times the stoichlometric quantities needed.29'30 This is much higher
5-37
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than the spray dryer absorber type systems and it makes this approach
unattractive for very large systems.
In one version of the dry injection system, solids are recycled from
the participate control device back into the flue gas contactor (sometimes
termed reactor). The primary purpose of the recycle stream is to increase
reagent utilization and thereby reduce overall calcium hydroxide costs.
5.3.2.1.3 Combination spray dryer and dry injection systems. A
flowchart for this system is provided in Figure 5-15. The acid gas laden
flue gas is first treated 1n an upflow type spray dryer absorber. A
series of calcium hydroxide sprays near the bottom of the absorber vessel
are used for droplet generation.
After the upflow chamber, the partially treated flue gas then passes
through a venturi contactor section where it is exposed to a calcium
silicate and lime suspension. The purpose of the second reagent material
is to improve the dust cake characteristics in the downstream fabric
filter and to optimize acid gas removal in this dust cake. The calcium
silicate reportedly improves dust cake porosity and serves as an adsorbent/
for the add gases.
SolIds collected 1n the fabric filter may be recycled to the venturi
contactor. This improves reagent utilization and facilitates additional
pollutant removal.
5.3.2.2 General Comments. Corrosion can present major problems for
all types of dry scrubbers used on applications with high hydrogen
chloride concentrations such as hospital waste incinerators. The calcium
chloride reaction product formed in the dry scrubbers and any unreacted
hydrogen chloride are both very corrosive and cause damage in any areas of
the absorber vessel or particulate control device where cooling and water
vapor condensation can occur. Two common reasons for low localized gas
temperatures include air infiltration and improper insulation around
support beams. Due to the potential problems related to corrosion, the
inspections should include checks for air infiltration and a visible
evaluation of common corrosion sites.
5-38
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5.3.3 Fabric Filters
Fabric filters are used on a limited number of hospital incinerators
for control of particulate matter emissions. They have some advantages
over wet scrubbers in that they are highly efficient at removing fine
particles if they are properly operated and maintained. However, their
performance can deteriorate rapidly in situations where poor O&M result in
bag blinding, bag corrosion, or bag erosion.
Generally, fabric filters are classified by the type of cleaning
mechanism that is used to remove the dust from the bags. The three types
of units are mechanical shakers, reverse air, and pulse jet. To date, the
only hospital incinerators that have been identified as having fabric
filters use pulse jet units. The paragraphs below briefly describe the
design and operating characteristics of pulse jet filters and identify key
design parameters.
A schematic of a pulse jet fabric filter is shown in Figure 5-16.
Bags 1n the fabric filter compartment are supported internally by rings or
cages. Bags are held firmly in place at the top by clasps and have an
enclosed bottom (usually a metal cap). Dust-laden gas is filtered through
the bag, depositing dust on the outside surface of the bag (an exterior
filtration system). The fabric filter is divided into a "clean" side and
"dirty" side by the tube sheet which is mounted near the top of the
unit. The dust-laden gas stream enters below this tube sheet and the
filtered gas collects in a plenum above the tube sheet. There are holes
in the tube sheet for each of the bags. The bags are normally arranged in
rows. The bags and cages hang from the tube sheet. Most pulse jet
filters use bag tubes that are 4 to 6 in. in diameter. Typically the bags
are 10 to 12 ft long, but they can be as long as 25 ft.
There are two major types of pulse jet fabric filters: (1) top
access, and (2) side access. Figure 5-17 illustrates the top access
design which includes a number of large hatches across the top of the
fabric filter for bag replacement and maintenance. Another major type has
one large hatch on the side for access to the bags. The side access units
often have a single small hatch on the top of the shell for routine
inspection of the fabric filter.
5-39
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TUMSMUT
CLEAN AIM PLENUM
PLENUM ACCESS'
TO CLEAN AIM OUTLET
AND EXHAUSTER
Figure 5-16. Schematic of pulse jet baghouse.
29
5-40
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TOP ACCESS HATCHES
GAS OUTLET
FAN
IAPHRAGM VALVES
AIR MANIFOLD
GAS INLET
OPPERS
Figure 5-17. Top access pulse jet fabric filter.
5-41
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Like most small units, the pulse jet collector depicted in
Figure 5-17 is not divided into compartments. These are not needed on
small units that operate intermittently since bags are cleaned row-by-row
as the unit continues to operate. A few of the large units are divided
into separate compartments so that it is possible to perform maintenance
work on part of the unit while the other part continues to operate.
Pulse jet cleaning is used for cleaning bags in an exterior
filtration system. The dust cake is removed from the bag by a blast of
compressed air injected into the top of the bag tube. The blast of
compressed air stops the normal flow of air through the filter. The air
blast develops into a standing or shock wave that causes the bag to flex
or expand as the shock wave travels down the bag tube. As the bag flexes,
the cake fractures and deposited particles are discharged from the bag.
The shock wave travels down and back up the tube in approximately
0.5 seconds. The compressed air is generated by an air compressor and
stored temporarily in the compressed air manifold. When the pilot valve
(a standard solenoid valve) is opened by the controller, the diaphragm
valve suddenly opens to let compressed air into the delivery tube which
serves a row of bags. There are holes in the delivery tube above each bag
for injection of the compressed air into the top of each bag. The
cleaning system controller can either operate on the basis of a
differential pressure sensor as shown in Figure 5-18, or it can simply
operate as a timer. In either case, bags are usually cleaned from once
every 5 minutes to once every hour. Cleaning is usually done by starting
with the first row of bags and proceeding through the remaining rows in
the order that they are mounted.
The blast of compressed air must be strong enough for the shock wave
to travel the length of the bag and shatter or crack the dust cake. Pulse
jet units use air supplies from a common header which feeds into a nozzle
located above each bag. In most fabric filter designs, a venturi sealed
at the top of each bag is used to create a large enough pulse to travel
down and up the bag. The pressures involved are commonly between 60 and
100 psig. The importance of the venturi is being questioned by some pulse
jet fabric filter vendors. Some fabric filters operate with only the
compressed air manifold above each bag.
5-42
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•LOW TU
LOT VALVE ENCLOSURE
DIAPHRAGM VALVE
•— AIR MANIFOLD —
PULSE TIMER
J
DIFFERENTIAL PRESSURE. SWITCH
IRTY GAS .INLET
IOTARY VALVE
Figure 5-18. Cross sectional sketch of pulse jet fabric filter.
5-43
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The presence of a row of diaphragm valves along the top of the fabric
filter indicates that the fabric filter is a pulse jet unit. These valves
control the compressed airflow into each row of bags which is used to
routinely clean the dust from the bags. On a few units, the diaphragm
valves cannot be seen since they are in an enclosed compartment on the top
of the unit. In these cases, the pulse jet fabric filter can be
recognized by the distinctive, regularly occurring sound of the operating
diaphragm valves.
The key design and operating parameters for a pulse jet filter are
the air-to-cloth ratio (or the filtration velocity), the bag material,
operating temperature, and operating pressure drop.
The air-to-cloth ratio is actually a measure of the superficial gas
velocity through the filter medium. It is a ratio of the flow rate of gas
through the fabric filter (at actual conditions) to the area of the bags
and is usually measured in units of acfm/ft2. No operating data were
obtained for hospital incinerators, but generally, the air-to-cloth ratio
on waste combustion units is in the range of 5 to 10 acfm/ft2 of bag ;
31
area.
Pulse jet units do not necessarily operate at the design average gas-
to-cloth ratio. When incinerator operating rates are low, the prevailing
average gas-to-cloth ratio could be substantially below the design
value. Conversely, the average gas-to-cloth ratio could be well above the
design value if some of the bags are inadequately cleaned or if sticky or
wet material blocks part of the fabric surface. Very high gas-to-cloth
ratio conditions can lead to high gas flow resistance which, in turn, can
result in both seepage of dust through the bags and fugitive emissions
from the incinerator or upstream dry scrubber.
Bag material generally is based on prior experience of the vendor.
Key factors that generally are considered are cleaning method, abrasive-
ness of the particulate matter and abrasion resistance of the material,
expected operating temperature, potential chemical degradation problems,
and cost. To date, no information has been obtained on types of material
typically used for hospital incinerator applications.
The operating temperature of the fabric filter is of critical
importance. Since the exhaust gas from hospital incinerators can contain
5-44
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HC1, the unit should be operated at sufficiently high temperatures to
assure that no surfaces drop below the acid dewpoint. Otherwise, conden-
sation of HC1 will result in corrosion of the housing or bags. The
boiling point of HC1 (aqueous hydrochloric acid) is 11Q°C (230°F); gas
temperatures should be maintained at 150°C (300°F) to ensure that no
surfaces are cooled below the dewpoint. Above a maximum temperature that
is dependent on filter type, bags will degrade or in some cases fail
completely. Gas temperatures should be kept safely below the allowed
maximum.
Pressure drop in fabric filters generally is maintained within a
narrow range. (For pulse jet filters the upper end of the range typically
is 8 to 10 in. w.c.). Pressure drops below the minimum indicate that
either: (1) leaks have developed, or (2) excessive cleaning is removing
the base cake from the bags. Either phenomena results in reduced
performance. Pressure drops greater than the maximum indicate that either
(1) bags are "blinding," or (b) excessive cake is building on the bags
because of insufficient cleaning. The primary result of excessive y
pressure drop is reduced flow through the system and positive pressure at
the incinerator. Over time, operating at high pressure drops also lead to
bag erosion and degradation.
5.3.4 Electrostatic Precipitators
A discussion on electrostatic precipitators was not included in this
inspection manual because, currently, they are not used to control
emissions from hospital waste incinerators. In general, ESP's are used to
control emissions from larger sources such as municipal waste
incinerators. Information on the application of ESP's to municipal
incinerators may be found in Reference 21.
5.4 REFERENCES FOR CHAPTER 5
1. Doucet, L. C. Controlled Air Incineration: Design, Procurement and
Operational Considerations. Prepared for the American Society of
Hospital Engineering, Technical Document No. 55872. January 1986.
2. Ontario Ministry of the Environment. Incinerator Design and
Operating Criteria, Volume II-Biomedical Waste Incineration.
October 1986.
3. Reference 1, p. 1.
5-45
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4. Ecolaire Combustion Products, Inc., Technical Article: "Principles
of Controlled Air Incineration."
5. Reference 1.
6. McRee, R. "Operation and Maintenance of Controlled Air
Incinerators."
7. Air Pollution Control District of Los Angeles County. Air Pollution
Engineering Manual, AP-40. U.S. EPA. May 1973.
8. Ecolaire Combustion Products, Inc., Technical Data Sheet for E Series
Incinerator.
9. Consumat Systems, Inc. Technical Data Sheet for Consumat Waste
Handling System.
10. Ashworth R. Batch Incinerators—Count Them In; Thermal Paper
Prepared for the National Symposium of Infectious Waste.
Washington, D.C. May 1988.
11. Ecolaire Combustion Products, Inc. Technical Sheet for the ECP
System.
12. Reference 7, p. 490. >
13. Reference 7, p. 439.
14. Hospital Waste Combustion Study: Data Gathering Phase. Final
Report. U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, North Carolina. EPA
450/3-88-017. December 1988.
15. Technical Data Form: Consertherm Systems, Industronics, Inc.
16. Joseph, J. G. and D. S. Beachler. APTI Course SI:412C, Wet Scrubber
Plan Review - Self-Instructional Guidebook. U. S. Environmental
Protection Agency. EPA 450/2-82-020. March 1984.
17. Ibid. p. 3-4.
18. Donnelly, J. R., Quach, M. T., and Moller, J. T. "Design Considera-
tions for Resource Recovery Spray Dryer Absorption Systems."
Presented at the 79th Annual Meeting of the A1r Pollution Control
Association, Minneapolis, Minnesota. June 1986.
19. Ferguson, W. G., Jr., Borio, D. C., and Bump, D. L. "Equipment
Design Considerations for the Control of Emissions From Waste-to-
Energy Facilities." Presented at the 79th Annual Meeting of the Air
Pollution Control Association, Minneapolis, Minnesota. June 1986.
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20. Sedman, C. 8., and Brna, T. G. "Municipal Waste Combustion Study
Flue Gas Cleaning Technology. U. S. Environmental Protection
Agency. Publication No. 530-SW-87-021d. June 1987.
21. Reference 19.
22. Reference 20.
23. Reference 19.
24. Moller, J. T., and Christiansen, 0. B. "Dry Scrubbing of MSW
Incinerator Flue Gas by Spray Dryer Absorption: New Developments in
Europe." Presented at the 78th Annual Meeting of the Air Pollution
Control Association, Detroit, Michigan. June 1985.
25. Foster, J. T., Hochhauser, M. L., Petti, V. J., Sandell, M. A., and
Porter, T. J. "Design and Startup of a Dry Scrubbing System for
Solid Partlculate and Acid Gas Control on a Municipal Refuse-Fired
Incinerator." Presented at the Air Pollution Control Association
Specialty Conference on Thermal Treatment of Municipal, Industrial,
and Hospital Wastes. Pittsburgh, Pennsylvania. November 4-6, 1987.
26. Ibid.
27. Reference 25.
28. Reference 26.
29. PEI Associates, Inc. Operation and Maintenance Manual for Fabric
Filters. U. S. Environmental Protection Agency, A1r and Energy
Engineering Research Laboratory, Research Triangle Park, North
Carolina. June 1986. EPA 625/1-86-020. p. 2-14.
30. Reference 20, p. 2-17.
5-47
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6.0 BASELINE INSPECTION PROCEDURES FOR HOSPITAL INCINERATORS
The primary objective of control agency inspections is to minimize
air pollution through promoting adherence to promulgated emission
regulations and permit stipulations. The inspection provides data for
determining the compliance status, helps identify sources of violation,
and provides information indicating the underlying causes of excess
emissions. The latter can be used in detailed negotiations with the
operators or in support of enforcement actions. The inspection also
provides a stimulus to the regulated industry by demonstrating the control
agency's determination to ensure continuous compliance. The baseline
inspection technique has been developed by EPA's Stationary Source
Compliance Division to aid both EPA Regional Offices and other control
agencies in conducting* effective and complete inspections of air pollution
control systems.
The primary purpose of this chapter is to describe the baseline
Inspection technique and illustrate how it should be applied to hospital ./
incinerators and control devices. In the part of the chapter devoted to
the baseline technique, a methodical approach is presented so that
Inspectors can obtain all the relevant data in an organized fashion.
These procedures are organized into "levels of inspection" (see
Section 6.2) reflecting the fact that there are different degrees of
intensity necessary for different situations. The inspection procedures
described in Sections 6.3 through 6.6 have been developed to ensure that
the data obtained is as accurate and complete as possible. These
procedures should be used by EPA field personnel unless there are
compelling technical or safety factors at a specific site which demand
modified approaches. In such a case, the reasons for the deviation from
the standard procedures should be briefly described in the inspection
report.
6.1 BASELINE INSPECTION TECHNIQUE
The baseline inspection technique can aid both the source operators
and the regulatory agency inspectors in routine evaluations of incinerator
and air pollution control equipment performance. The procedure is
designed to identify problems at an early stage, thereby minimizing both
6-1
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periods of excess emissions and equipment deterioration. By utilizing
similar evaluation approaches, inspectors and operators can communicate
effectively regarding the nature of any problem detected. This should
allow operating problems to be quickly corrected and reduce the number of
enforcement actions necessary.
6.1.1 Basic Principles
The fundamental principle underlying the baseline inspection
technique is that incinerator and control device performance be evaluated
primarily by comparison of present conditions with specific baseline
data. In other words, each separate incinerator system should be
approached initially with the assumption that its operating character-
istics and performance levels will be unique. It is necessary to take
this position since there are a myriad of process variables and control
device design factors which can singly or collectively influence operation
and performance levels. It is often difficult to determine why apparently
similar units operate quite differently with a limited amount of data.
Thus, a prime requirement of an inspection method (i.e., the baseline ,
technique) in ensuring the collection of useful data is the comparison of
conditions against a site-specific data base. Each variable which has
shifted significantly is considered a "symptom" of possible operation
problems.
While the baseline technique depends mainly on the machine-specific
data and shifts in performance levels over time, it should not be implied
that industry "norms" are irrelevant. There are cases in which deviations
from certain typical industry operating conditions can be an indication of
operation and maintenance problems. However, these data are considered
secondary to the site-specific data. The industry data are often
difficult to compile, and it is sometimes difficult to establish the
relevance of the data in enforcement proceedings.
One of the major problems in inspection of an air pollution control
system 1s that the instruments necessary to monitor basic operating
conditions are often either nonexistent or malfunctioning. Data quality
problems are especially severe on those units which are subject to
frequent excess emission incidents and are thereby of most interest to
control agencies. The design deficiencies or improper maintenance
6-2
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practices which have reduced the effectiveness of the incinerator or
control device usually have had a severe disabling effect on whatever
instrumentation is on the control device. For these reasons, it is rarely
wise to accept the data from onsite gauges at face value. The baseline
technique includes some routine checks of these onsite gauges. When there
is a question concerning the completeness or adequacy of the available
data, the inspector must obtain the data by means of portable instru-
ments. Such instruments can either be used by plant operators in the
presence of the inspector or can be used by the inspector directly.
Performance evaluations should be done by examination of a number of
different types of information. An emerging performance problem can often
be determined better by evaluating the set of variables rather than
relying on a shift in a single operating variable. Also, general
observations concerning the extent of corrosion, solids discharge rate,-
and fan physical conditions can be used to support preliminary conclusions
reached by examining the operating data. Failure characteristics on
materials removed from the collectors (e.g., bags, discharge electrodes, ,
nozzles) can be used to determine the type of corrective actions which
have a reasonable chance of being successful. The baseline inspection
technique Incorporates both measurements and observations.
It is recognized that the control agency inspection represents an
inconvenience to source personnel who must accompany the inspector while
he is on plant property. To minimize this inconvenience, EPA/State
inspectors should make every reasonable effort to reduce the time
necessary to complete the field activities. One means to accomplishing
this goal 1s to organize the data and observations in a coherent fashion
during the inspection and to use these data to focus the field work toward
the specific problems, if any, which appear to exist. If the initial
information clearly suggests that there are no present or emerging
problems, the inspection should be terminated. The baseline inspection
technique utilizes both counterflow and co-current flow approaches in
order to organize and focus inspection efforts.
6-3
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6.1.2 Counter-Flow Technique
The counter-flow approach is appropriate when the EPA inspector is
making a routine inspection of a facility for which baseline data is
available. Figure 6-1 illustrates the counterflow approach. It starts
with an observation of the stack opacity using Method 9 or equivalent
procedures. In addition to the changes in the average opacity since the
baseline period, the inspector evaluates the pattern of opacity
variability. The inspector also checks for fugitive emissions from
control device equipment, incinerator chambers (e.g., charging door) and
for emissions from bypass stacks. The next step is the evaluation of
transmissometer data (if applicable) assuming that the monitor passes
basic quality assurance requirements. The emphasis of the inspection is
on the operating conditions, both measured and observed. The control
device information coupled with the stack conditions can be used to
(1) determine if there is a probable problem, (2) determine if the problem
is due primarily to control-device-related conditions, and (3) determine
if the problem is due primarily to incinerator-related factors. If the
incineration process appears to be important, then the inspection should
continue with an evaluation of any relevant portions of the incinerator.
If the problem is simply control device related, the time-consuming
inspection of process sources can be either abbreviated or eliminated.
The counterflow approach should only be used when the baseline data is
available and the basic incineration process is well documented in the
agency files.
6.1.3 Co-Current Technique
The co-current inspection starts with the preparation of a flowchart
of the incineration/control device system. The inspector starts with the
waste storage area and follows the incineration process in a co-current
fashion. The emphasis in this type of inspection is on the waste material
and fuel characteristics, charging rates and procedures, operating
temperatures and pressures, and other information relevant to the
generation of air pollutants. The co-current flow approach is illustrated
in Figure 6-2.
Due to the diversity of hospital incinerators and control systems, it
is important that the inspection procedures incorporate some
6-4
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COUNTERFLOW APPROACH
PROCESS
GAS STREAM
CONTROL
DEVICE
Figure 6-1. Counterflow Inspection approach.
6-5
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CO-CURRENT APPROACH
-------
flexibility. The baseline inspection technique includes several levels of
intensity. These can be preselected by agency personnel before the
inspection, based on normal targeting criteria. The level also can be
changed by the inspector during the field work based on preliminary data
and observations. This .flexibility allows the agency to focus on actual
emission problems instead of simply completing a prescribed number of
inspections. The flexibility built into the baseline technique also must
be exercised whenever, in the judgment of the inspector, the standard
procedures would be unsafe or incorrect for a specific source. It also
should be noted that specific inspection activities can be deleted.
However, Inspectors should not add new or different procedures without the
express approval of supervisory personnel.
6.2 LEVELS OF INSPECTION
Without any constraints of Agency manpower and resources, it would be
desirable to conduct detailed engineering oriented inspections at all .
sources. This is obviously impractical due to the large number of air
pollution sources inspected regularly by EPA Regional Offices and the ./
State and local agencies. Levels of Inspection have been incorporated
into the Inspection program to give control agencies the opportunity to
properly allocate the limited resources available. The most complete and
time consuming evaluations are done only when preliminary information
indicates that there is or will soon be a significant emission problem.
The levels of inspection are designated as 1 through 4 with the
comprehensiveness of the evaluation increasing as the number increases.
The types of activities normally associated with each level and the
experience levels necessary to conduct the different levels vary
substantially.
6.2.1 Level 4 Inspections
The Level 4 Inspection is the most comprehensive of the four levels
and is done explicitly to gather baseline information for use later in
evaluating the performance of the specific sources at a given facility.
This type of inspection should be done jointly by a senior inspector and
the EPA, State, or local agency personnel who will be assigned
responsibility for the plant.
6-7
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The best time to conduct a baseline inspection (Level 4 inspection)
is during initial compliance testing. The initial compliance test
following the installation of the incinerator and/or control equipment is
preferred because the system is new and operating at conditions designed
and set by the vendor. Typically, incinerators and/or air pollution
control systems (APCS) are purchased with performance guarantees that
require emission tests demonstrating a prescribed performance level that
ensures compliance with applicable emission regulations. Data quality
problems associated with instrumentation (e.g., pressure gauges, thermo-
couples, and liquid flow meters) are minimized because they are new and
the vendor has ensured that they are operating properly to achieve
guaranteed performance. When baseline inspections are performed simul-
taneously with the initial compliance tests, documentation of the key
operating levels is established with credibility and reliability for
reference in followup Level 2 and 3 inspections. Comparison of data
collected on subsequent inspections can be compared to the baseline data
and will allow the inspector to identify differences in operating
conditions that may be causing compliance problems.
An important part of the Level 4 inspection is the preparation of
general incinerator and control device flowcharts. As a starting point,
the inspector should request the block flow diagrams or drawings for the
incineration system. Specific flowcharts should be prepared so that all
of the important information concerning measurement ports, locations of
bypass stacks, and locations of all monitoring devices are clearly
shown. In addition to the pollutants measured during the compliance test,
the performance of the hospital waste incineration system can be evaluated
by measuring stack effluent gases such as 02 and CO, by observing stack
gas opacity, by inspecting ash quality, and by recording air pollution
control device and Incinerator operating parameters (e.g., temperature,
draft, and pressure drop). Details should be noted on the locations where
waste is generated, the general composition (i.e., relative volumes of
infectious waste/general refuse, liquid/solid waste, plastic content) of
the waste, the charging frequency, the size of each charge, and the type
of waste charged in each charge. Additionally, samples of incinerator
ash, scrubber liquor, fabric filter catch, and/or dry scrubber absorption
sorbent also should be obtained for analysis.
6-8
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6.2.2 Level 3 Inspections
Level 3 Inspections are conducted only on those units with apparent
problems identified in a Level 2 inspection (discussed later). Where
necessary, portable gauges provided by the inspector are used to measure
certain operating parameters. The most commonly used types of instruments
are thermocouples and thermometers, combustion gas analyzers (02 and CO
monitors), differential pressure gauges, pH meters-or paper, and pitot
tubes.
The Level 3 inspection includes an evaluation of stack effluent
characteristics (02 and CO), CEM data records, control device performance
parameters, and the incinerator operating conditions (e.g., tempera-
ture). Infectious waste composition may be reviewed and samples of the
scrubber liquor and incinerator ash may be obtained for later
evaluation. Failed fabric filter bags or electrostatic precipitator
discharge electrodes may be obtained to confirm that the plant has
correctly identified the general type of problem(s). In some cases, the
Level 3 inspection will include an evaluation of the internal portions of ,
an air pollution control device. This is done simply by observing
conditions from an access hatch and under no circumstances should include
entry by the Inspector into the control device.
6.2.3 Level 2 Inspections
Level 2 Inspections are the most frequent types of inspections and
are important in that the observations made during these inspections
determine when a Level 3 inspection is needed.
The Level 2 inspection is a limited walk through evaluation of the
air pollution source and/or the air pollution control equipment. Entry to
the facility is necessary. Therefore, the administrative inspection
procedures specified in Chapter 2 of this manual should be followed. The
inspection can be performed either in a co-current or countercurrent
fashion depending on the anticipated types of problems. In either case,
the inspection data gathered is limited to that which can be provided by
onsite permanently mounted instrumentation and observation of operating
procedures. An important aspect of this type of inspection is the
evaluation of the accuracy of the data from this instrumentation. When
control devices are not in service during the plant inspection, the
6-9
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Level 2 inspections can include checks on their internal condition. This
internal check is- particularly useful for the evaluation of fabric filter
performance. The inspection involves observations from access hatches and
under no circumstances includes entry into the collector by the
inspector. When the Level 1 data and/or the preliminary observations
during Level 2 Inspections indicate problems, an inspector may wish to
conduct the more detailed and complete Level 3 inspection.
6.2.4 Level 1 Inspections
The Level 1 inspection is a field surveillance tool intended to
provide relatively frequent but very incomplete indications of source
performance. Because entry to the plant grounds is usually unnecessary,
the inspection is never announced in advance. The inspector makes visible
emission observations on the stacks which are visible from the plant
boundary and which can be properly observed given prevailing
meteorological conditions. Odor conditions are noted both upwind and
downwind of the facility. Unusual conditions provide the stimulus for an
in-plant inspection in the near future. If the visible emission observa-
tions and/or other observations provides the basis of a notice of viola-
tion, the Information should be transmitted to. hospital administr. tive
personnel immediately to-satisfy due process requirements.
The following sections define the specific inspection points included
in.Level 1, 2, and 3 Inspections of hospital waste incinerators and the
major types of air pollution control systems. Procedures involved in
preparation of baseline data (Level 4 inspections) also are covered since
the procedures differ for each type of system.. Additionally, matrices are
included in each section on waste characterization, combustion equipment,
and air pollution control equipment which summarize and compare the types
of inspections included in each inspection level.
6.3 COMMON INSPECTION ACTIVITIES
There are several inspection activities that are common to the
different types of inspections (i.e., inspections of waste, combustion
equipment, and air pollution control devices). These common activities
are described in this section to prevent their unnecessary repetition in
each of the following sections where they are applicable.
6-10
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6.3.1 Prepare a System Flowchart
System flowcharts are prepared during a Level 4 inspection by agency
management personnel or senior inspectors for use in subsequent inspec-
tions. Even a relatively simple chart is helpful both in preparing for
and during an inspection. In general, the system flowchart is made up of
three separate flowcharts; waste storage and handling, combustion equip-
ment, and air pollution control device(s). The specific requirements for
each of these flowcharts are presented in the following section.
6.3.2 Identify Potential Safety Problems
Agency management personnel and/or senior inspectors should identify
potential safety problems involved in standard Level 2/Level 3 inspections
at this site. To the extent-possible, the hospital personnel should
eliminate these hazards. For those hazards which cannot be eliminated,
agency personnel should prepare notes on how future inspections should be
liilted and should prepare a list of the necessary personnel safety
equipment. A partial list of common health and safety hazards include the
following: ,
1. Eye injuries while observing combustion conditions through
observations hatches;
2. Skin contact with sharps and infectious wastes;
3. Thermal burns due to contact with hot equipment.
4. Inhalation hazards due to fugitive leaks from high static
pressure scrubber vessels and ducts;
5. Eye hazards during sampling of scrubber liquor or exposure to
dry scrubber alkali solids and slurries;
6. Slippery walkways and ladders;
7. Fan disintegration;
8. Inhalation hazards due to fugitive leaks from dry scrubber inlet
breechings, absorber vessels, particulate control systems, and alkaline
reagent storage/preparation/supply equipment;
9. Corroded ductwork and particulate control devices;
10. High voltage in control cabinets;
11. Inhalation hazards due to low stack discharge points;
12. Weak catwalk and ladder supports;
13. Hot fabric filter roof surfaces;
6-11
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14. Compressed air gauges in close proximity to rotating equipment
cr hot surfaces;
15. Fugitive emissions from faerie filter cystem; and
16. Inhalation hazards from adjacent stacks and vents.
6.3.3 Evaluate Locations for Measurement Ports
Many existing incinerators and air pollution control devices do not
have convenient and safe ports that can be used for static pressure, gas
temperature, oxygen, and carbon monoxide measurements. One purpose of the
Level 4 inspection is to select (with the assistance of plan; personnel)
locations for ports to be installed at a later date to facilitate Level 3
inspections. Information regarding possible sample port locations for
incinerators and air pollution control devices is provided in the U. S.
EPA Publication titled, "Preferred Measurement Ports for Air Pollution
Control Systems," EPA 340/1-36-034.
6.3.4 Evaluate Visible Emissions
If weather conditions permit, determine the wet scrubber effluent
average opacity in accordance with EPA Method 9 procedures (o- other
required procedure). The observation should be conducted during routine
process operation and should last 6 to 30 minutes for each ^tack and
bypass vent. The observation should be made after the water droplets
contained 1n the plume vaporize (wnere the steam plume "breaks") or at the
stack discharge if there is not a steam plume present. The presence of a
particulate plume greater than 10 percent generally indicates a scrubber
operating problem and/or the generation of high concentrations of sub-
micron particles in the process and/or the presence of high concentrations
of vaporous material condensing in the effluent gas stream.
In addition to evaluating the average opacity, inspectors should scan
the visible emission observation worksheet to identify the maximum and
minimum short-term opacities. rhis is especially useful information if
there are variations in the incinerator operating condition during
charging, soot blowing of a waste heat boiler, or other cyclic activity.
The differences in the minimum and maximum opacities provides an
indication of changing particle size distributions.
If weather conditions are poor, an attempt should still be made to
determine if there are any visible emissions. Do not attempt to determine
6-12
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average opacity during adverse weather conditions. The presence of a
noticeable plume indicates air pollution control device operating
problems.
6.3.5 Evaluate Double-Pass Transmissometer Physical Condition
If a transmissometer is present, and if it is in an accessible
location, check the light source and retroreflector modules to confirm
that these are in good working order. Check that the main fan is working
and that there is a least one dust filter for the fan. On many commercial
models, it 1s also possible to check the instrument alignment without
adjusting the instrument. (NOTE: On some models, moving the dial to the
alignment check position will cause an alarm in the control room. This is
to be moved only by plant personnel and only when it will not disrupt
plant operations).
Some fabric filters have one or more single pass transmissometers on
outlet ducts. While these can provide seme useful information to the
system operators, these instruments do not provide data relevant to the
Inspection.
6.3.6 Evaluate Double-Pass Transmissometer Data.
Obtain the continuous opacity records and quickly scan the data for
the previous 12 months to determine time periods that had especially high
and especially low opacity. Select the dry scrubber operating logs and
the process operating logs that correspond with the times of the
monitoring Instrument charts/records selected. Compare the dry scrubber
operating data and process operating data against baseline information to
identify the general category of problem(s) causing the excess opacity
incidents. Evaluate the source's proposed corrective actions to minimize
this problem(s) in the future. During the inspection, if the unit is
working better than during other periods, it may be advisable to conduct
an unscheduled Inspection in the near future.
As part of the review of average opacity, scan the data to determine
the frequency of emission problems and to evaluate how rapidly the
operators are able to recognize and eliminate the condition.
Evaluate the average opacity data for selected days since the last
Inspection, 1f the transmissometer appears to be working properly.
Determine the frequency of emission problems and evaluate how rapidly the
6-13
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fabric filter operators are able to recognize and eliminate the
conditions.
6.3.7 Sulfur Dioxide, Nitrogen Oxides, and Hydrogen Chloride Monitor
Physical Conditions
If the monitors are in an accessible location, confirm that the
instruments are in good mechanical operating condition and that any sample
lines are intact. Check calibration and zero check records for all
instruments. Whenever working in the areas around the continuous emis-
sions monitors, inspectors should be cautious about fugitive leaks of
effluent gas.
6.3.8 Sulfur Dioxide, Nitrogen Oxides, and Hydrogen Chloride Emission Data
An inspection of monitoring data, similar to that conducted for
transmissometers (see Section 6.5.4.2.8), also should be made of the
monitoring data for sulfur dioxide, nitrogen oxides, and hydrogen chloride
monitors.
High emission rates of either sulfur dioxide or hydrogen chloride
indicate significant problems with the dry scrubber system. The general
classes of problems include but are not limited to poor alkaline reagent
reactivity, inadequate approach-to-saturation (wet-dry systems), low
reagent stoichiometric ratios, low inlet gas temperatures, and makeup
reagent supply problems. If high emission rates of either sulfur dioxide
or hydrogen chloride are observed during the inspection, facility
personnel should be consulted to determine both the cause of the
problem(s) and appropriate corrective action(s).
High nitrogen oxide concentrations indicate a problem with the
combustion equipment operation, an increase in the waste nitrogen content,
or a problem with the nitrogen oxides control system.
6.3.9 Modify Standard Inspection Checklists
Senior inspectors and/or agency management personnel should modify
the checklists presented in the Appendices of this manual to match the
specific conditions at the facility being inspected. Inspection points
which are irrelevant and unnecessarily time consuming should be omitted to
reduce the inspection time requirements and reduce the disruption of the
facility personnel's schedule. Also, any inspection steps which involve
unreasonable risks to the inspector, the plant personnel, or the equipment
6-14
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should be deleted. In some cases, it may be necessary to add other
Inspection points not discussed in this manual. At the conclusion of the
Level 4 inspection, the modified checklist should be included in the
inspection file.
6.4 CHARACTERIZATION OF WASTE
Hospital wastes are heterogeneous, consisting of general refuse,
laboratory and pharmaceutical chemicals and containers, and pathological
wastes; all or some of these wastes may contain pathogens or infectious
agents and may be considered infectious wastes. While most States
prohibit disposal of low-level radioactive waste in incinerators (unless
licensed for this use), there is also a potential for improper inclusion
of these wastes in incinerator charge material. General refuse from
hospitals is similar to generic wastes from residences and institutions,
and include artificial linens, paper, flowers, food, cans, diapers, and
plastic cups. Laboratory and pharmaceutical chemicals can include
alcohols, disinfectants, antineoplastic agents, and heavy metals, such as
mercury. Infectious wastes include isolation wastes (refuse associated
with Isolation patients), cultures and stocks of Infectious agents and
associated biologicals, human blood and blood products, pathological
wastes, contaminated sharps, and contaminated animal carcasses, body parts
and bedding.1 In the U.S., infectious wastes are required to be discarded
in orange or red plastic bags or containers. Containers should be marked
with the universal biological hazard symbol (Figure 6-3). Often these
"red bag" wastes may contain general refuse discarded along with the
infectious waste.
The purpose of characterizing waste during an inspection is to
identify the types of waste being burned in order to assess whether the
wastes are within any limitations stipulated in the operating permit or
State regulations. Furthermore, characterization of the waste will assist
in evaluating the potential impacts on pollutant formation, proper incin-
erator design and operation, air pollution control equipment performance,
and waste handling and charging practices that could potentially produce
fugitive emissions of infectious agents. Potential pollutants of concern
from hospital incinerators that are affected by waste composition include
partlculate matter, particulate metals, acid gases (hydrogen chloride
6-15
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Figure 6-3. The biological hazard symbol.
6-16
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(HCIJ, hydrogen fluoride, sulfur dioxide, sulfuric acid, nitrogen oxides),
toxic organics (e.g., dloxins and furans), radionuclides, and infectious
agents. The characteristics of the wastes that contribute to the forma-
tion and emission of these pollutants are discussed below.
Particulate matter. The quantity and characteristics of emissions of
partial late matter from the combustion of hospital wastes are determined
by three factors: (1) entrainment of noncombustible materials,
(2) Incomplete combustion of combustible materials, and (3) condensation
of vaporous material. The noncombustible materials contained in hospital
wastes are dependent on the ash content of the combustible materials and
other miscellaneous noncombustible materials contained 1n the wastes, such
as powdered inorganic materials and fines from the fracture of sharps.
Partlculate emissions from incomplete combustion of combustible materials
are Influenced by the moisture content, heating value, and bulk density of
the feed wastes. These factors should be considered in the design and
operation of the incinerator to maximize combustion efficiency.
Condensation of vaporous materials results from volatilization of
noncombustible substances that have vaporization temperatures within the
range of those in the primary chamber with subsequent cooling 1n the flue
gas. These materials usually condense on the surface of other fine
particles. Because of the inverse relationship between surface area and
particle size, condenslble materials are often selectively distributed on
fine particles which makes their capture by conventional air pollution
control devices difficult. Particulate emissions from one study of
18 uncontrolled hospital incinerators ranged from 1.37 to 36.49 Ib per ton
of feed with an average of 7.52 Ib/ton.
Particulate metals. Particulate metal emissions are dependent on the
metals content of the feed material. Metals may exist in the waste as
either parts of discarded instruments or utensils, in plastics and inks,
or as discarded heavy metals used in laboratories. An example is mercury
from dental clinics. Many metals are converted to oxides during combus-
tion and are emitted primarily as submicron to micron size particles.
Metals that volatilize at primary chamber temperatures may selectively
condense on small, difficult to control particles in the incinerator flue
gas. Metals generally thought to exhibit fine-particle enrichment are As,
Cd, Cr, Mn, N1, Mo, Pb, Sb, Se, V, and Zn."
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Add gases. Sulfur dioxide (S02) emissions are directly related to
the sulfur content of the waste material. Two parts by weight of S02 are
generated for each part of sulfur combusted. Alkaline materials that may
exist in the waste materials could potentially react with the S02 and
produce solid salts that would be either retained in the bottom ash or
emitted as particulate with the flue gas. However, the relatively large
amounts of halogenated plastics in typical hospital waste result in the
formation of HC1 which has a higher affinity for the available alkaline
materials. As a result, most of the sulfur in the waste is emitted as
S02t with a small amount emitted as sulfur trioxide (S03). Moisture in
the flue gas can react with the S02 and S03 to produce sulfuric acid.
Uncontrolled SOX emissions from one study of two hospital incinerators
ranged from 1.47 to 3.01 Ib per ton of feed with an average of
1.85 lb/ton.5
Halogens such as chlorine, fluorine, and bromine in the wastes will
produce HC1, hydrogen fluoride (HF), hydrogen bromide (HBr) when
combusted. Potential sources of halogens in the waste stream include _,
polyvinyl chloride (PVC), other halogenated plastics, and halogen-
containing salts. Because of the relatively large amounts of plastics in
hospital wastes, concentrations of HC1 from hospital incinerators can be
significantly higher than from municipal incinerators. Hospital wastes
typically contain about 20 percent plastics with levels as high as
30 percent reported.6 Table 6-1 presents an ultimate analysis of four
plastics usually found in hospital wastes. Uncontrolled HC1 emissions
from hospital incinerators from one study of 18 hospitals ranged from 6.6
to 99.4 Ib per ton of feed with an average of 45.4 lb/ton.
Nitrous oxides (NOX) emissions from hospital incinerators result from
conversion of the nitrogen in the combustion air, referred to as thermal
NOX, and the nitrogen contained in the fuel, fuel NOX. Thermal NOX is
extremely sensitive to temperature. Fuel NOX is less temperature
sensitive and will increase proportionally with waste nitrogen content.3
Uncontrolled NOX emissions from one study of two hospital incinerators
ranged from 4.64 to 7.82 Ib per ton of feed with an average of
6.02 lb/ton.9
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TABLE" 6-1. ULTIMATE ANALYSES OF FOUR PLASTICS3
(Weight Percent)
Moisture
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Chlorine
Ash
Higher heating
value, Btu/lb
Polyethylene
0.20
84.38
14.14
0.00
0.06
0.03
Tr
1.19
19,687
Polystyrene
0.20
86.91
8.42
3.96
0.21
0.02
Tr
0.45
16,419
Polyurethane
0.20
63.14
6.25
17.61
5.98
0.02
2.42
4.38
11,203
Polyvinyl
chloride
0.20
45.04
5.60
1.56
0.08
0.14
45.32
2.06
9,754
Reference 10.
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Infectious agents or pathogens. Hospital incinerators have
traditionally been used to treat infectious wastes. The presence of
infectious wastes in the incinerator feed is easily identified by red or
orange plastic bags or containers marked with the biological hazard
symbol. Proper operation of the incinerator with adequate combustion
temperatures, excess air rates, and retention times should effectively
destroy the pathogens. Many States now require combustion temperature of
1800*F and retention times in the secondary chamber of 1 second. Because
of the potential for fugitive releases of Infectious agents, bag and
container integrity should be maintained. Bags and containers should be-
handled, transported, and stored in a manner that will prevent tears. If
syringes or other sharps are included, these sharp wastes should be placed
in rigid, puncture-resistant containers.
6.4.1 Waste Characteristics That Affect Incinerator Operation
Waste moisture and heat content have major impacts on the thermal
input to the incinerator. The heating value of waste corresponds to the
quantity of heat released when the waste is burned, commonly expressed in
Btu/lb. The net heating value of a waste decreases with increased
moisture content since approximately 1,200 Btu of heat are necessary to
evaporate each pound of water in the waste. The net heating value of the
waste should be considered in assessing the need for auxiliary fuel
firing. As a rule of thumb, a minimum heat content of about 5,000 Btu/lb
is required to sustain combustion.11 Most incinerator manufacturers rate
the burn rate capacities for their units utilizing the Incinerator
Institute of America (IIA) Solid Waste Classification system which is
based on moisture content and heating value. The IIA was absorbed by the
National Solid Wastes Management Association in 1974. Table 6-2 presents
the IIA classification system.
Wide variations in thermal input will affect the temperatures, excess
air rates, and retention times required for efficient combustion. Charge
rates should be varied with the moisture content and heating value to
prevent overcharging or refractory damage and slagging. During normal
operation of the incinerator, the operator should mix feed material with
different heating values to prevent upset combustion conditions. The
loading hopper should be loaded with bags of red bag waste, trash, and
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TABLE 6-2. INCINERATOR INSTITUTE OF AMERICA SOLID WASTE CLASSIFICATIONS4
Type Description
0 Trash, a mixture of highly combustible waste such as paper,
cardboard, cartons, wood boxes, and combustible floor sweepings
from commercial and industrial activities. The mixture contain
up to 10 percent by weight of plastic bags, coated
paper,laminated paper, treated corrugated cardboard, oil rags,
and plastic or rubber scraps.
This type of waste contains 10 percent moisture, 5 percent
incombustible solids and has a heating value of 8,500 Btu per
pound as fired.
1 Rubbish, a mixture of combustible waste such as paper,'cardboard
cartons, wood scrap, foliage, and combustible floor sweepings,
from domestic, commercial, and industrial activities. The
mixture contains up to 20 percent by weight of restaurant or
cafeteria waste, but contains little or no treated papers,
plastics, or rubber wastes.
This type of waste contains 25 percent moisture, 10 percent
incombustible solids and has a heating value of 6,500 Btu per
pound as fired.
2 Refuse, consisting of an approximately even mixture of rubbish and
garbage by weight.
This type of waste is common to apartment and residential
•occupancy, consisting of up to 50 percent, moisture, 7 percent
incombustible sol Ids, and has a heating value of 4,300 Btu per
pound as fired.
3 Garbage, consisting of animal and vegetable wastes from
restaurants, cafeterias, hotels, hospitals, markets, and like
installations.
This type of waste contains up to 70 percent moisutre, up to
5 percent incombustible solids, and has a heating value of 2,500
Btu per pound as fired.
4 Human and animal remains, consisting of carcasses, organs, and
solid organic wastes from hospitals, laboratories, abattoirs,
animal pounds, and similar sources, consisting of up to
85 percent moisture, 5 percent incombustible solids, and having a
heating value of 1,000 Btu per pound as fired.
5 Byproduct waste, gaseous, liquid or semi liquid, such as tar,
paints, solvents, sludge, fumes, etc., from industrial
operations. Btu values must be determined by the individual
materials to be destroyed.
6 Solid byproduct waste, such as rubber, plastics, wood waste, etc.,
from industrial operations. Btu values must be determined by the
individual materials to be destroyed.
Reference 12.
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garbage, rather than charging all the red bag waste at one time, then all
the garbage, etc. The objective is to maintain a constant thermal input
rate (Btu/h).
Wastes containing metals and plastics are a particular concern for
pollutants from hospital incinerators. When burned, metals may become
metal oxides with particle size distributions primarily in the submicron
to micron size range. These small particles may become easily entrained
with limited capture by conventional air pollution control equipment.
Some plastics such as polyethylene and polystyrene do not contain
significant amounts of halogens and can be incinerated efficiently without
major concern for toxic pollutant formation. However, the high heating
value of these and other plastic materials can cause excessively high
temperatures in the primary combustion chambers with increased potential
for refractory -damage, slagging, and clinker formation. Chlorinated
plastics, such as polyvinyl chloride, produce HC1.
6.4.2 Handling of Infectious Wastes
Infectious wastes require unique handling, transport, and charging
procedures to prevent fugitive emissions of infectious agents. Infectious
waste should be transported to the incinerator in either red or orange
plastic bags or 1n containers marked with the biological hazard symbol.
In no case should the inspector open the bags or containers. Handling and
transport of these wastes should be performed with care to protect the
integrity of the bags and to ensure containment of the wastes. In
general, plastic bags containing infectious waste should not be
transported through a chute or loaded by mechanical devices. Storage of
these wastes prior to incineration should be in a specially designated
area with limited access. The area should be kept clean and free of
rodents and vermin. Storage temperature and duration should be kept to a
minimum to limit microbial growth and putrefaction. The presence of
obnoxious odors may indicate that materials are being stored for excessive
periods of time at elevated temperatures. If a continuous feed
incinerator is used to burn both infectious wastes and general refuse,
infectious waste should not be charged to the incinerator during startup
unless the incinerator is brought to proper operating temperature on
fossil fuel. It is recommended that general refuse be charged until the
unit is operating at normal combustion chamber temperatures.
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6.4.3 Waste Inspection
6.4.3.1 General Considerations. Inspection of waste at a hospital
waste Incineration facility is an important part of each inspection
regardless of whether a Level 4, 3, or 2 inspection is performed. The
main purpose of the waste inspection from an air inspector's perspective
is to gather data to determine the potential for fugitive emissions (i.e.,
odors, particulate) and stack emission problems related to waste
composition (e.g., high plastic content). The air inspector will probably
not have authority regarding waste handling or management at the
facility. However, he/she can be on the look out for potential
infractions by reviewing operating permits, noting any prohibited wastes
(e.g., low-level radioactive, hazardous wastes) and observing the waste
contents. For example, an incinerator that does not have an Nuclear
Regulation Commission (NRC) permit or a permit from an agreement State (a
State that has an agreement with the NRC to issue permits) for burning
•low-level radioactive waste should not be burning such waste. Similarly,
an incinerator without a RCRA permit or State permit/license cannot burn '
hazardous waste. However, the air Inspector should be concerned mainly
with identifying the components in the waste that could contribute to
stack emissions and with observing the waste storage and handling
procedures that could promote fugitive emissions of particulate matter
and/or odors. Table 6-3 presents a matrix that shows the types of waste
inspections Included in each inspection level.
6.4.3.2 Level 4 Waste Inspection Procedures. The Level 4 waste
inspection procedures include the following: preparation of a waste
generation, storage, and handling flowchart; the identification of
potential safety problems, the review of waste management records; the
characterization of waste composition; the observation of waste storage
and handling procedures; and the preparation of a waste inspection
checklist. These procedures are discussed in detail below.
6.4.3.2.1 Preparation of flowchart. A flowchart of the waste
generation, handling, storage, and charging system should be prepared for
use in subsequent Level 2 and 3 inspections. It should consist of a chart
that identifies:
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TABLE 6-3. MATRIX OF MEDICAL WASTE INSPECTION ACTIVITIES
ASSOCIATED WITH INSPECTION LEVELS 1, 2, 3, AND 4
Followup
Inspection activity/ equipment Level 4 Level 3 Level 2
1.
2.
3.
4.
S.
Prepare waste management system flowchart x
Identify potential safety problems x x x
Modify standard inspection checklist x
Summarize waste management records x
Estimate the relative volumes of the following:
a. General refuse x x
b. Red Bag wast* x x
c. Solid waste x x
d. Liquid wast* x x
*. Plastic wast* ' x x
f. PVC plastic wast* « x
g. Metals x x
h. Toxic materials x x
i. Radioactive materials x x
Basic
Level 2 Level I Text reference
6.4.3.2.1
x x 6.3.2
6.3.9
6.4.3.2.3
6.4.3.2.4
6. EstiMte the following properties of the waste:
a. Moisture content
b. Bulk density
7. Perfora waste survey if warranted
3. Evaluate «aste handling procedure by:
t. Checking for properly labeled/colored
packages
5. Checking for liquids packed In capped or
stoppered bottles/flasks
c. Noting whether contaminated sharps are
packed in rigid, puncture-resistant
containers
d. Checking packaging integrity
e. Noting tears, punctures, and leaking -liquids
f. Oeternining potential for ruptures of waste
packaging
9. Evaluate wast* storage procedures by:
a. Inspecting packaging for lean, ruptures.
and leaking liquids
b. Estimating storage temperature (I.e..
Moient)
c. Measuring storage te*v*ratur*
d. Oeternining waste storage durations by
consulting hospital records or
personnel
e. Note 9enera) housekeeping procedures
10. Determine if prohibited wastes are being
incinerated
6.4.3.2.4
6.4.3.2.4
6.4.3.2.5
6.4.3.2.6
6.4.3.2.3
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1. Generation sites of infectious and laboratory wastes;
2. Method of transporting to storage area;
3. Any refuse holding or staging area;
4. Storage areas and charging pits, chutes, or rams,
6.4.3.2.2 Identify potential safety problems. The identification of
potential safety problems is addressed 1n Section 6.3.2.
6.4.3.2.3 Waste management records. A summary of the normal waste
generation and management records, if any, maintained by the hospital
should be compiled. These data will be invaluable during Levels 2 and 3
inspections since Infectious waste will be contained in plastic bags or
containers at the incinerator site and should not be opened by the
inspector. Prohibited wastes should be listed. Special procedures for
handling bulk liquids (if any) should be addressed.
As soon as regulations have been promulgated implementing the Medical
Waste Tracking Act of 1988, medical facilities in the 10 affected States
will be required to keep records regarding waste generation. Therefore,
inspectors in these States will be able to determine to some extent the
types and volumes of waste being incinerated. The requirements for these
facilities under this pilot program are detailed in Section 2.2.2.3.
Eventually, all 50 States may have to implement a tracking system
depending on the success of this pilot program.
6.4.3.2.4 Waste composition. The waste produced by a hospital for •
incineration can vary in composition from day-to-day or hour-to-hour. The
incinerator is designed to handle a particular range of waste physical and
chemical properties. Operation of the incinerator should be varied with
respect to feed rates, combustion air rates, and auxiliary fuel firing to
account for the variation in wastes charged. The range of variation in
waste composition that can be successfully processed by the incinerator
with routine operational adjustments represents the baseline waste levels
(i.e., the waste being burned is within the heat content range for which
the incinerator was designed).
The relative distribution (i.e., fraction of total waste) and volumes
(e.g., the number of 13-gallon size waste bags) of general refuse versus
infectious "red bag" wastes should be estimated and noted during the
inspection. Depending upon the packaging procedures for hospital waste,
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it may be difficult for the inspector to assess the waste composition.
Infectious waste bags or containers should not be opened by the
inspector. If there are questions about waste composition, the
appropriate hospital personnel should be located and questioned. If
possible, the physical nature of the waste with respect to solids and
liquids should be noted (I.e., are bottles of liquids being incinerated).
Large quantities of liquid wastes should not be incinerated unless the
incinerator is designed for their combustion, i.e., includes properly
designed hearths with catch troughs or special injection nozzles. Waste
components with high moisture contents (e.g., pathological waste) and high
bulk densities (e.g., compacted waste, computer paper) should be noted..
Special care should be taken to note any potentially toxic material, such
as mercury, contained in the waste stream. The plastic content of the
wastes also should be identified. If possible through consultation with
hospital personnel, the inspector should identify the relative portion of
the plastics that are halogenated plastic, i.e., PVC.
During a Level 3 or Level 2 inspection (I.e., inspection prompted by ;
public complaints and/or continued compliance problems), in some cases, it
may be necessary to evaluate the waste composition and heat content more
accurately. The most realistic method of obtaining more accurate
information on the waste Is to consult the waste management records at the
hospital to identify each waste type generated and to determine the rate
at which each waste type is generated. This information allows weight
fractions for each waste type based on the total amount of waste generated
to be calculated. (If records are unavailable, a waste generation survey
may be required.) A chemical analysis could then be performed by an
experienced laboratory on a representative sample of each waste type. The
heat content of the waste can be estimated using waste fractions and
tabulated heat contents for each waste type. This type of analysis need
only be performed if the cause of the problem prompting the inspection is
suspected to be the waste mixture, i.e., if the incinerator and air
pollution control device are operating properly and consequently, waste
problems are indicated.
6.4.3.2.5 Handling practices—infectious waste. Handling practices
are of concern to the air pollution inspector because of the potential for
6-26
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fugitive releases of pathogens or toxic chemicals. For proper
accreditation, each hospital should have in place a waste management plan
for infectious and toxic wastes. These plans should require that the
waste material be disposed in properly marked containers that prevent
release of the wastes and exposure to humans. Liquid infectious wastes
should be placed in capped or tightly stoppered bottles or flasks. Solid
or senrlsolld Infectious wastes should be placed in red or orange plastic
bags or marked containers. Contaminated sharps should be placed in
impervious, rigid, and puncture-resistant containers. The infectious
wastes should be transported to the incineration facility in these bags or
containers. The .inspector should visually inspect the bags and containers
at the incineration facility to ensure that the integrity of the packaging
is being maintained. Obvious tears, ruptures, or leaking liquids should
be noted. Handling practices at the incineration facility should be
evaluated to assess the potential for tearing or rupturing the packaging
materials. In general, these plastic bags and containers should be moved
by hand without the use of mechanical loaders or manually loaded carefully
into dumpsters for transport.
Observations should be made of material charging practices. Because
of the possible variations 1n feed material moisture and heat contents,
materials of varying heat and moisture values should be mixed to produce a
heterogenous feed charge with relatively consistent combustion
characteristics.
6.4.3.2.6 Storage practices—infectious waste. Ideally, infectious
wastes should be incinerated as soon as possible after generation.
However, same-day incineration is not always possible, necessitating
storage of the material at the incineration facility. The four important
factors to be considered in storing infectious wastes are protecting the
integrity of the packaging, storage temperature, duration of storage, and
design of the storage area. The packaging should be inspected to ensure
that there are no ruptures, tears, or leaking liquids. Storage
temperature and duration affect microbial growth and putrefaction.
Inspectors should note any odors and should review hospital records or
consult operators to assess storage times. Temperatures in the storage
area should be measured and noted. Storage of material for longer than 4
6-27
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to 5 days should only be allowed in refrigerated facilities. The storage
area itself should be specially designated with limited access. The
Inspector should note general housekeeping procedures to prevent vermin or
rodent Infestation that could damage the integrity of the containment
packaging.
6.4.3.2.7 Preparation of site-specific checklist. The senior
inspection personnel should prepare a site-specific waste inspection
checklist for the hospital. The checklist should specify the specific
waste conditions and locations to be Inspected. The checklist should note
any site-specific safety hazards associated with each inspection point.
Additionally, the checklist should include permit specifications or
regulations that limit storage duration and temperature and that exclude
certain wastes from being incinerated or that allow incineration of
certain wastes. An example of a waste inspection checklist is included as
Appendix A.
6.5 EVALUATION OF COMBUSTION EQUIPMENT
Variations 1n emission rates from hospital incinerators are due to >•
variations 1n the chemical and physical properties of the hospital wastes,
variations 1n Incinerator design, and variations in Incinerator opera-
tion. The baseline inspection technique 1s predicated on establishing
baseline conditions and evaluating variations in performance that result
from shifts 1n operating conditions. Incinerator design does not vary
over time. Inspections of waste characteristic effects were discussed in
Section 6.3. The purpose of this section is to present background
information on how combustion processes influence pollutant formation and
emission rates, how Incinerator operation can be adjusted to reduce
emissions, and guidance on how to perform inspections of the incinerator
itself.
6.5.1 Participate Matter and Particulate Metals
As stated in Section 6.4.1, particulate emissions from hospital
incinerators are determined by three factors: (1) entrainment of
noncombustible materials (2) incomplete combustion of combustible
materials, and (3) condensation of vaporous materials. The presence of
noncombustible materials 1n the incinerator feed is a characteristic of
the waste feed material. This noncombustible material or ash can either
6-28
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be retained in the incinerator bottom ash or be entrained and emitted with
the flue gas. The potential for entrainment of the ash is a function of
the incinerator design and operation and will increase with increased
turbulence and gas velocities in the primary combustion chamber. The
relatively lower turbulence and gas velocities in the primary combustion
chamber of a controlled-air incinerator (compared to a multiple-chamber
design) contributes to the relatively lower particulate emission rates
from these types of units. Complete combustion of combustible material
requires adequate temperatures, excess air, turbulence or mixing, and
retention time. Because of the variability in hospital waste with respect
to heating values, moisture contents, etc., incinerator operating
parameters should be varied with the variations in the waste to maximize
combustion. In general, higher temperatures, excess air rates,
turbulence, and retention time result in improved combustion. However,
factors that result in higher gas velocities (e.g., higher excess air
rate) can result 1n increased particulate entrainment.
Condensation of vaporous materials occurs when temperatures in the
primary chamber exceed the volatilization temperature of the material with
subsequent cooling and condensation in the flue gas exhaust. Generally,
primary chamber combustion temperatures should be in the range of 1400° to
1800°F for good combustion. Temperatures in excess of 1800T may result
in excessive slagging and refractory damage.
6.5.2 Acid Gases
The principal acid gas of concern from hospital incinerators is
HC1. The determining factor in HC1 formation and emission is the
availability of chlorine in the feed material. Combustion modifications
and incinerator operational adjustments have little, if any, affect on HC1
generation and emissions. In the presence of available hydrogen, as would
exist in the typical highly organic hospital wastes, most of the available
chlorine will be converted to HC1.
From an incinerator design and operation standpoint, S02 is like
HC1. Most of the sulfur in the wastes will be converted to S02 regardless
of incinerator design or operation.
Of the principal add gases, only NOX formation will be significantly
affected by incinerator design and operation. The two types of NOX
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formation mechanisms are thermal formation and waste feed nitrogen conver-
sion. Thermal NOX results from exposure of air to high temperatures in
the combustion zone. The higher the excess-air rate at the flame zone,
the higher the thermal NOX formation potential. Fuel NOX formation is
less temperature sensitive than thermal NOX and is more dependent on the
waste nitrogen content. NOX formation in hospital incinerators should be
lower than in coal-fired boilers due to the relatively lower flame
temperatures. Thermal and fuel NOX formation is lower in starved-air
units than in excess-air units due to the staged combustion design.
Operational modifications that lower excess-air rates and temperatures
will reduce NOX formation. However, these same modifications may result
in lower combustion efficiency with resulting increases in particulate
emissions and dioxin and furan formation.
6.5.3 Organics
Combustion conditions that favor increased particulate emissions due
to incompletT~combustion also favor increased organic emissions. Organic
material is found 1n the waste and can be formed during combustion. S1nce>
these formation mechanisms are not fully understood, there are no
straight-forward design procedures or operating procedures that can-
prevent the formation of all organic compounds. Instead, reliance is
placed on the destruction of the pollutants created in the combustion
process. There are three basic goals for controlling the emission of
organics, namely:
1. Mixing of fuel and air to minimize the existence of long-lived,
fuel-rich pockets of combustion products;
2. Attainment of sufficiently high temperatures in the presence of
oxygen for the destruction of hydrocarbon species; and
3. Prevention of quench zones or low temperature pathways that will
allow partially combusted waste (solid or gaseous) from exiting the
combustion chamber.
6.5.4 Infectious Agents
Incineration has been traditionally used to treat infectious waste at
hospitals. Incineration is especially advantageous with pathological
wastes and contaminated sharps because it renders body parts unrecogniz-
able and sharps unuseable. Properly designed and operated incinerators
6-30
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can be effective in killing organisms present in the waste. In general,
combustion conditions that are favorable to complete combustion and low
particulate emissions are also favorable to sterilizing infectious
wastes. Because of the variation in the moisture content and heating
value of infectious waste, it is important to adjust waste feed and excess
air rates to maintain proper incineration conditions. It is important to
avoid overloading. When incinerating hospital wastes, it is essential
that the secondary chamber operating temperatures be attained before
loading the waste.
6.5.5 Inspection of Combustion Equipment
This section provides detailed descriptions of the types of
inspections required when inspecting combustion equipment. Section 6.4.5.1
provides an overview of the types of inspections that should be performed
and questions that should be answered on a combustion equipment inspec-
tion. Section 6.4.5.2 provides detailed descriptions of each inspection
activity that should be performed on a Level 4 Inspection. Table 6-4 is a
matrix that identifies the various inspection activities and the inspec- j
tlon level 1n which they are included.
6.5.5.1 Combustion Equipment Inspection Overview.
6.5.5.1.1 Incinerator.
Charging system/procedures
• Determine if the facility has a written standard procedure for
charging waste.
— Maximum load size
— Minimum time between charges
— Minimum/maximum primary chamber temperature
— Minimum/maximum secondary chamber temperature
~ Are charges logged and charging rate measured?
• Examine condition of mechanical charging equipment
— Are isolation doors air tight?
— Does charge ram have water quench sprays? Are they working?
~ Is spillage of infectious waste materials and subsequent
contamination of surrounding area prevalent?
— Do procedures exist for disinfecting hopper/ram assembly?
6-31
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TABLE 6-4. MATRIX OF COMBUSTION EQUIPMENT INSPECTION ACTIVITIES
ASSOCIATED WITH INSPECTION LEVELS 1, 2, 3, AND 4
Inspection activity/equipment
Level 4 Level 3
Followup
Level 2
8*S1C
Level 2
Level 1 fe«t reference
1. Evaluate Incinerator visible emissions
2. Prepare system flowchart
3. Identify potential safety problems
4. Evaluate location) for measurement ports
S. Modify standard inspection check lists
6. Review all available records
7. Haste charging procedures
a. Obtain waste feed rate
b. Review charging records for overcharging
c. Observe charging procedures
3. Observe combustion zone condition
a. Note burner flame pattern
b. Note combustion zone condition (color)
c. Note ash bed condition
9. Observe bottom asn condition/handling
a. Observe ash handling practices
b. Take VE readings wnen fugitive dust is
apparent
c. Inspect ash for burnout
d. Review ash disposal records
e. Obtain ash sample
10. Evaluate startup/shutdown procedures
a. Proper •inimum temperatures achieved Before
charging
b. Proper waste charging
c. Observe stack gas opacity during startup/
shutdown
II. Underflre and overflre air ports
a. Record incinerator airflow or air pressure
If monitor available
b. Obtain readings for previous 9 hours
c. Review operator's log to determine frequency
of cleaning
12. Incinerator draft—record Incinerator static
pressure If monitor available
13. Primary and secondary chamber temperature
a. Record primary and secondary temperatures
from control panel
b. Review previous 12 months data
c. Measure exit gas temperature
14. Oxygen (0 ) level
a. Record exit gas 0 level from available
monitor
b. Review prevou* 12 months' data
c. Measure exit gas 0 level
15. Carbon •ononde (CO) level
a. Record exit gas CO level from available
•onltor
b. Review previous 12 months' data
c. Measure exit gas CO level
IS. Incinerator shell
a. Inspect exterior shell for corrosion
b. Inspect exterior shell for wnite spots
c. listen for audible air Infiltration
17. Incinerator charging area
a. Listen for audible air Infiltration
b. Inspect charge door for warping
13. Evaluate general physical condition of:
a. Incinerator
b. Transmissometer
c. Sulfur dioxide monitor
d. Nitrogen oxides monitor
e. HC1 monitor
19. Review opacity. SO
emission data
..
and HC1 monitors
S.3.4
6.5.5.2.1
6.3.2
6.3.3
6.3.9
5.5.5.2.5
6.5.5.2.6
6.5.5.2.7
6.5.5.2.14
6.5.5.2.19
6.5.5.2.8. 9
6.5.5.2.10
S. 5.5.2.11
6.5.5.2.12
6.5.5.2.13
6.5.5.2.15, 16
6.5.5.2.17
6-32
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• Observe charging procedure
-- Evaluate temporal variations in waste and combustion
conditions. Does operator adjust waste charging or combustion
conditions to accommodate variations?
• Are fugitive emissions from incinerator/charge assembly emitted
during charging?
• If bulk liquids are being handled, are these properly fed to the
incinerator via burner or atomizing nozzle?
• If pathological (Type 4) waste is being incinerated, is/are
charging rate/procedures appropriate for this waste type?
Incineration system/procedures.
1. Evaluate adequacy of primary chamber and secondary chamber exit
gas temperatures. These are important operating parameters relating to
combustion efficiency and infectious agent destruction. Gas temperature
also affects nitrogen oxides generation by thermal mechanisms.
2. Evaluate flue gas oxygen concentrations to assure adequate
excess air is available. High levels may also indicate air >
infiltration.
3. Evaluate CO concentration of exhaust gas. Excessive CO
indicates poor combustion conditions.
4. Evaluate physical condition of incinerator shell and waste feed
delivery equipment. Check for audible air infiltration into incinerator
and for audible air losses from undergrate plenums and forced draft supply
ducts.
5. Inspect physical condition of air blower/burner assemblies.
a. Do combustion air fans appear to be operating smoothly (no
squealing or vibration)? Physical condition of dampers (rusted or
properly lubricated)? For automatic modulated systems, are dampers
modulating as thermal load to incinerator changes?
b. Visually inspect burner assemblies and flame pattern (if
viewports exist). For automatic systems, are burners modulating with
thermal load of incinerator?
6. If pathological wastes are charged to incinerator, are proper
operating conditions maintained? (i.e., does the primary chamber burner
remain on?)
6-33
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7. Evaluate stack emissions
a. Visually observe the stack emissions opacity
b. For cases where a bypass stack is present, observe whether
emissions are present from the bypass stack.
8. Note whether the incinerator draft is measured/recorded
9. Inspect data recording systems to assure all parameters which
are required to be monitored by the operating permit are monitored and
that data recording systems are operating properly. Depending upon the
size/operating frequency of the unit and operating permit conditions,
monitored parameters for the'combustion system can include any of the
following:
a. Primary chamber temperature;
b. Secondary chamber temperature;
c. Oxygen concentration of the effluent gas;
d. Carbon monoxide concentration of the effluent gas;
e. Opacity of the effluent gas;
f. Combustion chamber pressures (draft); >
g. Charging frequency and mass;
h. Ash removal frequency;
i. Auxiliary fuel usage.
10. Review startup and shutdown procedures since these can cause
short term emission problems and can lead to rapid equipment deteriora-
tion. For batch feed units, the charging and startup of the incinerator
should be observed during an inspection. Insure that secondary chamber
temperatures have reached acceptable levels before infectious wastes are
charged.
6.5.5.1.2 Residue handling and disposal.
1. Check any available records concerning incinerator bottom ash
composition since this could indicate combustion problems.
2. Inspect bottom ash to determine obvious combustion problems.
3. Observe bottom ash cleanout, storage, and disposal procedures for
fugitive particulate emissions.
6.5.5.2 Level 4 Combustion Equipment Inspection. The Level 4
combustion equipment inspection is a comprehensive inspection that
includes all of the elements of Inspection Levels 1, 2, and 3. Table 6-4
6-34
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.provides a matrix of the types of inspection activities included in each
inspection level for combustion equipment. The following paragraphs
describe the Level 4 combustion equipment inspection activities in detail
while the matrix points out differences between the different levels.
6.5.5.2.1 Prepare a system flowchart. A combustion equipment system
flowchart should consist of a simple diagram that includes the following
elements:
1. Location of waste storage and handling area and schematic of
waste charging system;
2. Incinerator chamber(s), overfire and underfire air ports; blowers
and air auxiliary burner locations;
3. Location of incinerator chamber viewports;
4. Schematic of ash handling system and disposal/storage area;
5. Locations of major instruments and monitoring locations on the
equipment (static pressure gauges, temperature monitors, oxygen analyzers,
carbon monoxide analyzers, and operating meter); and
6. Location of control panel and monitor output and recording j
instrumentation.
6.5.5.2.2 Identify potential safety problems. The identification of
potential safety problems 1s addressed in Section 6.3.2.
6.5.5.2.3 Evaluate potential safety problems. The evaluation of
locations for measurement ports 1s discussed in Section 6.3.3.
6.5.5.2.4 Evaluate the incinerator visible emissions. The evaluation
of visible emissions is discussed in Section 6.3.4.
6.5.5.2.5 Review types of records. A summary of the normal operating
•
records and routine laboratory analyses (e.g., analysis of incinerator
ash, baghouse catch, scrubber sludge) should be compiled. If possible,
example photocopies of these forms should be included in the inspection
file so that new personnel assigned inspection responsibilities will know
what data and information are'available on these forms.
6.5.5.2.6 Waste charging practices. Waste composition affects
combustion conditions due to variations in moisture content and heating
value. The incinerator's control system can operate only within a
specified range to control air levels and auxiliary fuel. Therefore, it
1s Important to establish a proper loading rate to maintain the proper
6-35
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combination of fuel, excess-air rate, and temperature for effective
combustion. If waste compositions vary dramatically, it may be necessary
to vary the charging rate. When wastes are fed to the incinerator,
different waste types should be mixed to achieve a more uniform moisture
content and heating value. Large volumes of plastic should not be charged
all at once due to possible high temperature damage to the refractory and
slagging. If infectious wastes containing pathogens are included in the
waste feed, it is important that the secondary chamber gas temperature be
brought up to normal operating temperatures before any infectious wastes
are fed to the unit. Overloading, which often results in incomplete
combustion, should be avoided. The incinerator should be rated by the
manufacturer for feed rates for the various Incinerator Institute of
America waste classes. Obtain the feed rate that prevails during the
inspection and visually identify, if possible, the waste composition and
moisture content. This feed rate and waste class can then be compared to
the specifications from the incinerator manufacturer. Batch loading units
should be loaded as quickly as possible, especially if the refractory is
still warm from the previous burn. If a hot unit is loaded and not sealed
properly in a short period of time, the remaining heat in the firebrick
may ignite the waste while improper combustion conditions exist in the
unit.
6.5.5.2.7 Evaluate combustion zone condition. If viewports are
installed in the combustion chambers, the inspector should visually
inspect the combustion zone(s). Only glass covered viewports should be
used. The inspector should not open charging doors, ash removal doors, or
inspection doors to view the combustion chambers since serious'injury can
result.
During visual inspection, the observer should note:
1. The flame pattern;
2. Combustion zone condition (color); and
3. Ash bed condition.
The flame should not be smoking or impinging on the refractory wall.
For starved-air units, the primary chamber should be operating at
substoichiometric conditions and consequently the combustion zone should
be quiescent (entrainment of large particles/pieces of waste to the
6-36
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secondary chamber should not occur) and dark red or orange in color.
Complete combustion should be occurring in the secondary chamber where the
combustion zone should appear bright orange/yellow. For intermittent duty
and continuous-duty incinerators, the waste/ash bed should be signifi-
cantly reduced in volume (50 to 75 percent) before another charge is
loaded into the incinerator. Pathological waste must be exposed to the
flame; consequently, the waste bed should not be deeply piled.
6.5.5.2.8 Evaluate underfire air ports. If monitors are available
that measure airflow rate or air pressure, readings should be taken of the
values Indicated. If readings are recorded by operator personnel, obtain
readings taken for the last 8 hours. The inspector should review the
operator's log to determine the frequency of cleaning of the air ports.
6.5.5.2.9 Evaluate overfire air ports. Same procedure as underfire
air ports.
6.5.5.2.10 Evaluate incinerator draft. - If pressure monitoring
gauges are available, recordings of the static pressure should be taken.
Incinerator drafts that are 0.0 inches of water or higher demonstrate that/
the incinerator is operating under a positive pressure. This positive
pressure Indicates a severe combustion problem and a severe personnel.
exposure problem. Under no circumstances should the Incinerator operate
with positive pressures. Positive pressure indicates an induced draft fan
problem or a gas flow resistance problem either in the incinerator or in
the air pollution control system.
6.5.5.2.11 Evaluate primary and secondary gas temperatures. The
primary and secondary chamber exit gas temperatures are usually monitored
by thermocouples. These data can be obtained from the main incinerator
control panels. However, in some of the especially small units, this is
not recorded on a continuous basis. The gas temperature records (if
records are kept) since the last inspection should be reviewed to identify
any problems in maintaining acceptable primary and secondary chamber gas
temperatures. The auxiliary burners are used to maintain minimum
temperature during periods of waste feed interruption or during periods
when excessive quantities of wet or noncombustible waste have been
charged. The gas temperature fluctuations and the status of the auxiliary
burner may be determined by scanning the dally operating logs of the
6-37
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Incinerator, by scanning available temperature record strip charts, or by
reviewing operator logs.
Measurements should be taken of exit gas temperature at the stack or
breeching as close to the exit of the secondary combustion chamber as
practicable. The data should be compared to any available baseline data
as well as to the incinerator thermocouple data to determine if a
significant change in temperature exists.
The appropriate temperature in the primary chamber for effective
burnout and 1n the secondary chamber for effective combustion will vary
with each Individual unit. Baseline unit-specific temperatures should be
set during the Level 4 Inspection.
6.5.5.2.12 Evaluate exit gas oxygen level. If available, the
continuous oxygen analyzer data for the past year should be scanned to
determine if the oxygen concentrations have remained in the.normal
range. The typical oxygen concentrations are generally in the range of 6
to 12 percent. Values lower than 6 percent generally indicate inadequate
excess air rates and incomplete combustion of volatile compounds. Values -
higher than 12 percent generally indicate severe air infiltration through
the charging area, the incinerator shell, or the ash pit. The values
presented here are typical values. However, incinerator-specific baseline
levels should be set during the Level 4 inspection. Subsequent inspec-
tions should compare observed values to the baseline values for the
particular unit being inspected. Instrument calibration and routine
maintenance records should be reviewed.
The exit gas oxygen concentration should be measured when there are
indications of combustion related emission problems and when there is no
onsite oxygen analyzer. When an oxygen analyzer is present, measurement
of oxygen levels by the inspector can be used to verify the accuracy of
the onsite monitor.
The types of instruments available include multigas combustion gas
analyzers, ORSAT analyzers, and manual single-gas absorbers. The oxygen
concentration should be measured at several locations along the duct
diameter. Stratification of the gas stream can result in nonuniform
oxygen concentrations across the duct diameter. Also, the measurements
should be repeated several times over a reasonable time span to account
6-38
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for short terra fluctuations in the oxygen levels. This is especially
important since charging can create frequent short term oxygen
concentration changes. The EPA Reference Method 3 (40 CFR Part 60
Appendix A) should be used as a guide for making oxygen measurements.
6.5.5.2.13 Evaluate exit gas carbon monoxide level. Exit gas carbon
monoxide level is used as one of the indirect indicators of the
completeness of combustion. Observed CO levels should be compared with
baseline levels for the unit. Higher than normal CO values suggest
significant combustion problems. Plant personnel should be asked about
possible corrective actions to improve combustion. Also, the instrument
calibration and routine maintenance records should be briefly reviewed.
Carbon monoxide concentration measurements should be made when there
are indications of combustion problems and when there is no carbon
monoxide analyzer installed on the unit. Values greater than normal
baseline values suggest nonideal combustion conditions and the emission of
partially combusted organic compounds. To ensure representative results,
the measurements should be made at several locations in the duct and
should be made several times over a reasonable time span. When the
facility' does have a CO monitor installed, measurement of CO levels by the
Inspector can be used to verify the accuracy of the facility's monitor.
6.5.5.2.14 Evaluate ash handling practices. Ash handling practices
should be observed and noted. The inspector should observe manual removal
of the ash from the incinerator for batch and intermittent duty
incinerators and inspection of the mechanical removal systems for
continuous duty incinerators. Additionally, the inspector should evaluate
the measures taken to prevent fugitive dust emissions including quenching
the ash and the placement of the ash in a covered metal container.
Visible emission observations should be performed whenever there are
apparent fugitive emissions from the bottom ash handling equipment. Ash
storage procedures should be observed and any fugitive emissions noted.
The ash should be inspected for burnout quality. Large pieces of
uncombusted material indicates poor burnout. Records should be reviewed
to determine ultimate disposal methods and procedures.
Samples should be obtained of the ash and sent to a laboratory for
analysis of the combustible organic content and other contaminants such as
6-39
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pathogens and metals. The samples should be handled carefully and
properly marked as potentially -containing infectious organisms.
6.5.5.2.15 Evaluate incinerator shell corrosion. Evaluate the
exterior of both the primary and secondary chambers for signs of
corrosion. This can be caused by the infiltration of cold air that in
turn results in the absorption of highly corrosive hydrogen chloride into
water droplets on the metal surfaces. The air infiltration condition
worsens as the corrosion continues. This can lead to "cold" zones in the
affected chamber and thereby contribute to increased emissions of
partially combusted organic compounds.
6.5.5.2.16 Evaluate incinerator shell audible air infiltration.
This condition leads to cold zones within the incinerator and increased
emissions of partially combusted or reacted organic compounds. Most of
these leaks occur in the refractory in inaccessible locations.
6.5.5.2.17 Evaluate audible air infiltration through charging
area. Air infiltration through warped charging doors can lead to
localized "cold" zones in the primary chamber. It can also cause some >
undesirable particle reentrainment and carryover into the secondary
chamber. Care must be exercised in attempting to find audible leaks,
since there may be moving equipment around the charge pit and since there
can be fugitive pollutant emissions accumulating in the poorly ventilated
areas around the primary chambers.
6.5.5.2.18 Review charging records. Available charging records
should be reviewed to determine if the incinerator capacity is being
exceeded and if proper charging procedures are being followed. Where
charging records are not available, observation of the charging procedures
over an extended period of time (1 to 2 days) may be warranted.
6.5.5.2.19 Evaluate startup and shutdown procedures. If the
facility has frequent startups, the startup and shutdown procedures should
be evaluated. All batch type and intermittent duty incinerators fall into
this category. The emphasis should be on techniques used to maintain
minimum furnace exit gas temperatures and on the criteria for beginning
waste charging to the unit. Stack gas opacity should be observed to
determine the duration of nonideal combustion conditions after waste
charging has begun. If a problem is evident, continuous measurement of CO
6-40
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and 02 levels in the combustion gas may be warranted. Detailed startup
and shutdown procedures for different types of incinerators are provided
in Section 7.4.
6.6 INSPECTION OF AIR POLLUTION CONTROLS15
6.6.1 Inspection of Wet Scrubbers
6.6.1.1 Wet Scrubber Inspection Overview.
6.6.1.1.1 Stack.
1. Average opacity of the residual plume is observed since this
provides an Indication of particulate matter penetration and vapor
condensation in the scrubber.
2. Short-term variations in residual opacity are an indication of
variations in combustion conditions.
3. Obvious mist reentrainment is a clear indication of demister
failure.
6.6.1.1.2 Induced draft fan.
1. Inspectors must be aware of severely vibrating fans downstream
from wet scrubbers. The Inspection is terminated immediately when this isy
noticed.
6.6.1.1.3 Scrubber.
1. Static pressure drop across the scrubber is used as an indirect
indicator of the particulate removal effectiveness. The present value is
compared with baseline values to determine if there has been a significant
decrease.
2. Scrubber static pressure drop records for the time since the last
inspection are reviewed to identify any operating periods with low
pressure drops.
3. Scrubber vessel general physical condition is observed during the
walkthrough inspection to identify any obvious physical conditions which
could threaten the compliance status of the unit in the immediate future.
4. Redrculatlon liquor turbidity rates are observed using a small
sample provided by plant personnel. High turbidities indicate greater
chance of nozzle pluggage, nozzle erosion, and pipe scaling.
5. Presaturator/gas cooler liquor turbidity is observed using a small
sample provided by plant personnel. Moderate turbidities indicate the
potential for severe particle generation due to evaporation of the solids-
containing droplets.
6-41
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6. Redrculation liquor pH provides an indirect indication of the
scrubber vessel's capacity to absorb acid gases. This is also important
with respect to corrosion of the scrubber vessel, the recirculation tank,
and the piping.
7. Scrubber vessel liquor header pressure is used as an indirect
indicator of the condition of internal nozzles which cannot be seen during
the inspection. Higher than baseline values may indicate pluggage.
8. Demlster pressure drop is a direct indicator of partial pluggage
and reduced droplet collection efficiency. The present value should be
compared with baseline values.
9. Scrubber outlet gas temperature is an indicator of the adequacy of
the gas-liquor distribution within the scrubber vessel. Values above
adiabatic saturation suggest severe gas-liquor maldistribution.
10. Induced draft fan"motor currents provide an indirect indicator of
gas flow rates through the scrubber.
11. Audible air infiltration sites are noted since this contributes to
scrubber vessel corrosion. j
6.6.1.2 Level 4 wet scrubber inspection. The Level 4 wet scrubber
inspection 1s a comprehensive inspection that includes all of the elements
of Inspection Levels 1, 2, and 3. Table 6-5 provides a matrix of the
types of Inspection activities included 1n each inspection level for air
pollution control devices including wet scrubbers. The following
paragraphs describe the Level 4 wet scrubber inspection activities in
detail while the matrix points out differences between the different
levels.
6.6.1.2.1 Prepare a system flowchart. A wet scrubber system flowchart
should consist of a simple block diagram which includes the following
elements:
1. Source or sources of emissions controlled by a single wet
scrubber system;
2. Location(s) of any fans used for gas movement through the system
(used to evaluate inhalation hazards due to positive static pressures);
3. Locations of any main stacks and bypass stacks;
4. Location of wet scrubber; and
6-42
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TABLE 6-5. MATRIX OF AIR POLLUTION CONTROL DEVICE INSPECTION ACTIVITIES
ASSOCIATED WITH INSPECTION LEVELS 1, 2, 3, AND 4
Inspection activ1ty/»quioaent Level 4
wet
I.
2.
3.
4.
S.
6.
7.
a.
9.
10.
11.
12.
13.
14.
IS.
16.
scrubbers
Evaluate wet scrubber visible Missions
Prepare syftea f lowcnart
Identify potential safety probleas
Evaluate locations for neasureaent ports
Modify standard inspection checklists
Inspect for drool it reentratnaent
*. Quell for ralnout of drool tts adjacent
to the stack
b. Check for •olsture/stalnt on adjacent
support coluans/tams/stacks
c. Mad Hp at stack discharge
Evaluate liquor inlet prtssurt
tnducad-draft fan
a. CkKk fan for vibration
b. Chock fan aetor current
Scrubber liquor pM
4. Review routine pM eeter calibration records
b. If aeter properly calibrated, observe
previous •onths' data
c. Measure scrubber outlet liquor on*
Scrubber Hquor flow rate
4. Record liquor flow rate fro* available nonitor
b. Record ouoe discharge pressure from qauqe
c. Record nozzle header pressure from qauqe
Scrubber static pressure drop
a. Record scrubber static pressure readlnqs
froa available nonuor
b. Measure scrubber static pressure drop
fro* available nonltor
Record dealster static pressure drop froa
available Monitor
Measure outlet qas teaoerature
Evaluate general physical condition of:
a. Met scrubber systea
b. Packed bedi
c. Venturl throat daaeers
d. Transalssoaeter
e. Sulfur dloilde «on(tor
f. Rltroqen oaldes aonitor
q. Hydrogen chloride eonitor
Observe turbidity of:
a. Scrubber Inlet Hquor
b. Preiaturator/cooler liquor
Review opacity. SO . NO . HC1 wnitors'
ealsslon data ' '
1
X
I
•
*
•
X
«
<
X
X
Jf
1
•
I
X
X
X
X
X
X
*
X
X
X
X
X
X
X
X
X
X
Followuo Basic
Level 3 Lev*) Z Levt) Z
XXX
xxx
XXX
XI*
xxx
XXX
xxx
X X
X C
« X
«
XXI
xxx
« X X
« X X
X
X X
X
X X
X
X
X X
X X
X X
X X
X X
X
4 X
lev«1 I Text referenct
i 6.6. 1. 1. 1.
6. 6. L. 2.1
x 6.3.2
6.3.3
6.3.9
6.6.1.2.6
6.6.1.2.3
6.6.1.2.5
6.6.1.2.11
6.6.1.2.12
6.6.1.2.7
6.6.1.2.14
•*
6.6.1.2.16
6. 1.2. IS
Ory scrubbers
I. Evaluate dry scrubber visible Missions
2. Pieueie systea flowchart
3. Identify potential safety problem
4. Evaluate locations for aeasureaent ports
S. Modify standard Inspection checklists
6. Note condensing pluae conditions
7. Record feed rates for the follovlnq systeas
froa available aonitors
a. Spray dryer absorber (caldua hydroxide)
b. Ory Injection (caliua hydroxide)
c. S«a1«et/dry (calctua siHcate/calciua
hydroxide)
3. Evaluate general physical condition of:
a. Ory scrubber
b. Transaissoaeter
c. Sulfur dioxide aonitor
d. Nitrogen oxides aonitor
e. Hydrogen chloride aonitor
9. Record solids recycle rate on seaiwec/dry
systeas
10. Record spray dryer absorber systea nozzle air
and slurry pressures
6.6.2.1.1
6.6.2.2.1
6.3.2
S.J.3
6.3.9
6.6.2.2.6
6.6.2.2.8. 10. 11
6.6.2.2.13
6.6.2.2.2
6.6.2.2.9
(continued)
6-43
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TABLE 6-5. (continued)
Inspection activity/equipment
level 4 Level 3
FollowiP
Level 2
Basic
Level 2
Level 1 Text reference
Dry scrubbers (continued)
11. Met and dry bulb temperatures
a. Record vet *nd dry bulb temperatures fro*
available monitors
b. Measure wet wd dry bulb temperatures
12. Review the previous 12 «onthV data for the
rollowing:
a. Opacity
b. Spray dryer absorber appreecn-to-saturatlon
(wet/dry bulb temperatures)
c. Spray dryer absorber reament feed rate
6. Slaker slurry outlet tirnun ature
e. Spray dryer absorber slurry flow rate and
density monitor maintenance records
f. Spray dryer absorber inlet gas tenoerature
9. Dry injection systM feee) rate
h. Semiwet/dry calcium silicate/cilclu*.
hydroxide feed rate
U. *ea«ur« tpray dryer aosorber/dry Injection
system inlet temperature
U. Review opacity. SO., NO . and XI
monitors' emission data
Fabric filters
1.
2.
3.
4.
S.
6.
;.
a.
9.
10.
U.
12.
13.
U.
15.
16.
U.
18.
19.
b.
c.
d.
e.
Evaluate fabric filter visible emissions
Prepare system flowchart
Prepare compressed-air system flownart
Evaluate locations for measurement ports
Identify potential safety prMlems
Modify standard inspection checklist
Evaluate startup/shutdown procedures
Evaluate puffing conditions
Evaluate condensing, plume conditions
Evaluate physical condition of:
a. Fabric filter
Transmissometer
Sulfur dlonlde monitor
Nitrogen ondes monitor
Kydroqen cnloHde monitor
Evaluate fabric filter clean-side conditions
Evaluate compressed-air cleaning system
Confirm operation of cleaning equipment controllers
Evaluate fabric performance
a. Perform faerie rip test
b. Evaluate bao, failure records
Evaluate baa, cages
Static pressure drop
a. Record static pressure drop from available
monitor
b. Measure static pressure drop
Gas temperatures
a. Record fnlet and outlet gas temperatures from
available monitors
b. Review fabric filter temperature records
c. Measure Inlet and outlet gas temperatures
Measure inlet/outlet onyqen levels
Review opacity, SO , "0 and HC1 monitor's
data z *
6.6.2.2.7
6.6.2.2.16
5.6.2.1.2
6.6.3.1.1. 2
6.6.3.2.1
6.6.3.2.2
6.3.3
6.3.2
6.3.9
6.6.3.2.4
6.6.3.2.7
6.6.3.2.8
6.6.3.2.10
6.6.3.2.1
6.6.3.2.12
6.6.3.2. IS
6.6.3.2.18
6.6.3.2.9
6.6.3.2.14, IS
6.6.3.2.19
6-44
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5. Locations of major instruments (pH meters, static pressure
gauges, thermocouples, liquor flow meters).
6.6.1.2.2 Identify potential safety problems. The identification of
potential safety problems is addressed in Section 6.3.2.
6.6.1.2.3 Evaluate locations for measurement ports. The evaluation of
locations for measurement ports is discussed in Section 6.3.3.
6.6.1.2.4 Evaluate the wet scrubber visible emissions. The evaluation
of visible emissions 1s discussed in Section 6.3.4.
6.6.1.2.5 Observe induced-draft fan vibration. If the fan downstream
of
the scrubber vessel 1s vibrating severely, the inspection should be
terminated at once and responsible plant personnel should be advised of
the condition. Fans can disintegrate due to fan wheel corrosion, fan
wheel solids buildup, bearing failure, and operation in an unstable
aerodynamic range. All of these are possible downstream of the wet
scrubber. Shrapnel from the disintegrating fan can cause fatal injuries.
6.6.1.2.6 Evaluate droplet reentrainment. Droplet reentrainment j
Indicates a significant demlster problem which can create a local nuisance
and which can affect stack sampling results. The presence of droplet
reentrainment is Indicated by the conditions listed below:
1. Obvious ralnout of droplets in the immediate vicinity of the
stack;
2. Moisture and stains on adjacent support columns, tanks, and
stacks; and
3. Mud lip around the stack discharge.
6.6.1.2.7 Measure the wet scrubber static pressure drop. The static
pressure drop is directly related to the effectiveness of particle
impaction for particle capture. Generally, the particulate removal
efficiency increases as the static pressure drop increases. The steps in
measuring the static pressure drop are described below.
1. Locate safe and convenient measurement ports. In some cases it
may be possible to temporarily disconnect the onsite gauge in order to use
the portable static pressure gauge. It also may be possible to find small
ports 1n the ductwork ahead of and after the scrubber vessel.
2. Clean any deposits out of the measurement ports.
6-45
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3. If the Inlet and outlet ports are close together, connect both
sides of the static pressure gauge to the ports and observe the static
pressure for a period of 1 to 5 minutes.
4. If the ports are not close together, measure the static pressure
in one port for 10 to 30 seconds and then proceed to the other port for 10
to 30 seconds. As long as the static pressure drop is reasonably stable
(the typical condition) then the two values can be subtracted to determine
the static pressure drop.
5. Under no circumstances should onsite instruments be disconnected
without the explicit approval of responsible plant personnel. Also,
instruments connected to differential pressure transducers should not be
disconnected.
If a portable pressure gauge is unavailable, the wet scrubber static
pressure drop should be recorded if the onsite gauge appears to be working
properly. The following items should be checked to confirm the adequacy
of the onsite gauge.
1. The gauge "face" should be clear of obvious water and deposits; >
and
2. The lines leading to the inlet and outlet of the scrubber appear
to be intact.
If there is any question concerning the gauge, ask plant personnel to
disconnect each line one at a time to see if the gauge responds. If it
does not move when a line is disconnected, the line may be plugged or the
gauge is inoperable. Note: the lines should only be disconnected by
plant personnel and only when this will not affect plant operations.
Wet scrubber systems operate with a wide range of static pressure
drops as indicated in the list below.
Packed bed—2 to 6 in. w.c.
Venturi—10 to 40 in. w.c.
It should also be rioted that there is a wide range of required static
pressure drops for identical wet scrubbers operating on similar industrial
processes due to the differences in particle size distributions. For
these reasons, it is preferable to compare the present readings with the
baseline values for this specific source.
6-46
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Increased static pressure drops generally indicate the following
possible condition(s).
1. Packed-bed scrubbers
• High gas flow rates
• Partial bed pluggage
2. Venturi scrubbers
• High gas flow rate
• High liquor flow rates
• Constricted venturi throats
• Mlsadjustment of variable throat activator
Decreased static pressure drops generally indicate the following
possible condition(s).
1. Packed-bed scrubbers
• Low gas flow rates
• Bed collapse
2. Venturi scrubbers
• Low gas flow rate
• Low liquor flow rates
• Eroded venturi dampers
• Increased venturi throat openings
• Mlsadjustment of variable throat activator
6.6.1.2.8 Evaluate the liquor inlet pressure. The pressure of the
header which supplies the scrubber spray nozzle can provide an indirect
indication of the liquor flow rate and the nozzle condition. When the
present value is lower than the baseline value(s) the liquor flow rate has
increased and there is a possibility of nozzle orifice erosion.
Conversely, if the present value is higher than the baseline value(s) the
liquor flow rate has decreased and nozzle and/or header pluggage is
possible.
Unfortunately, these pressure gauges are very vulnerable to error due
to sol Ids deposits and corrosion. It is difficult to confirm that these
are working properly. For these reasons, other indicators of low liquor
flow such as the pump discharge pressure and the outlet gas temperature
should be checked whenever low header or pipe pressures are observed.
6-47
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6.6.1.2.9 Evaluate the wet scrubber system general physical
conditions. While walking around the wet scrubber system and its inlet
and outlet ductwork, check for obvious corrosion and erosion. If any
material damage is evident, check for fugitive emissions (positive
pressure systems) or air infiltration (negative pressure systems). Avoid
inhalation hazards and walking hazards while checking the scrubber system
general physical condition. Prepare a sketch showing the locations of the
corrosion and/or erosion damage. In addition to corrosion and erosion,
inspectors should also check for any of the conditions listed below.
1. Cracked or worn ductwork expansion joints;
2. Obviously sagging piping; and
3. Pipes which cannot be drained and/or flushed.
6.6.1.2.10 Evaluate the liquor turbidity. Ask a responsible and
experienced plant representative to obtain a sample of the liquor entering
the scrubber vessel. This can usually be obtained at a sample tap
downstream from the main recirculation pump. The agency inspector should
provide a clear sample bottle. Observe the turbidity of the liquor for a^
few seconds immediately after the sample is taken. The turbidity should
be qualitatively evaluated as clear, very light, light, -moderate, heavy,
or very heavy.
On some hospital incinerators, the inlet gas temperature may be
reduced prior to entry to the scrubber. This may be done by means of a
presaturator immediately upstream of the scrubber vessel. There is the
potential for small particle formation as the droplets containing solids
evaporate to dryness. The turbidity of the liquor used in the
presaturator should be very low to avoid this condition.
6.6.1.2.11 Measure the scrubber outlet Hquor pH. Prior to
obtaining a liquor sample, warm up the portable pH meter and check it
using at least two different fresh buffer solutions which bracket the
normal liquor pH range. Then request a responsible and experienced plant
representative to obtain a sample of the scrubber outlet liquor. Measure
the liquor pH as soon as possible after obtaining the sample so that the
value does not change due to dissolution of alkaline material or due to
ongoing reactions. Compare this to the baseline value(s).
6-43
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If the Inspector does not have a portable pH meter, the pH may be
checked by using the following steps. Locate the onsite pH meter(s).
Permanently mounted units are generally In the recirculation tank or in
the liquor outlet lines from the scrubber vessel. Confirm that the
Instrument is working properly by reviewing the routine calibration
records. In some cases, it is possible to watch plant personnel calibrate
these Instruments during the inspection.
If the pH meter(s) appears to be working properly, review the pH data
for at least the previous month. In units with Instruments on the outlet
and the Inlet, the outlet values are often 0.5 to 2.0 pH units lower due
to the adsorption of carbon dioxide, sulfur dioxide, hydrogen chloride,
and other add gases. Generally, all of the pH measurements should be
within the range from 5.5 to 10.0. Furthermore, any significant shifts in
the pH values from baseline conditions can indicate acid gas removal
problems and corrosion problems.
Corrosion can be severe in most systems when the pH levels are less
than 5.5. Also, high chloride concentrations accelerate corrosion at low y
pH levels. Precipitation of calcium and magnesium compounds at pH levels
above 10 can lead to severe scaling and gas-liquor maldistribution.
6.6.1.2.12 Evaluate the scrubber liquor recirculation rate. One
frequent cause of scrubber emission problems is inadequate liquor
recirculation rate. Unfortunately, many commercial types of liquor flow
monitors are subject to frequent maintenance problems and many small
systems do not have any liquor flow meters at all. For these reasons, a
combination of factors are considered to determine if the scrubber liquor
recirculation rate is much less than the baseline level(s). These factors
include the following:
1. Liquor flow meter (if available, and 1f it appears to be working
properly);
2. Pump discharge pressure (higher values indicate lower flow);
3. Pump motor current (lower values indicate lower flow);
4. Nozzle header pressure (higher values indicate lower flow);
5. Scrubber exit gas temperature (higher values indicate lower
flow); and
6-49
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6. Quantity of liquor draining back into recirculation tank or pond
(lower flow rates indicate lower recirculation rates).
6.6.1.2.13 Evaluate fan motor currents. Changes in gas flow rate
occur routinely in most incinerators due to variations in charging rates
and waste heating values. Information concerning gas flow rate changes is
necessary when evaluating changes in the scrubber static pressure drop.
Check the scrubber system fan motor current. Correct the fan motor
current to standard conditions using the equation below.
Corrected current = [actual current]x[(gas temp.+460)/520|
An Increase in the fan motor current indicates an increase in the gas
flow rate.
6.6.1.2.14 Evaluate demlster conditions. The static pressure drop
across the demister should be noted and compared with the baseline
values. An increase in the pressure drop normally is due to deposits
which partially plug the demister vanes. The static pressure drops of
clean demisters are usually in the range of 1 to 2 inches of water.
6.6.1.2.15 Evaluate physical condition of scrubber packed beds and ,
venturi throat dampers. This inspection step can be performed only when
the scrubber system is out-of-service. Locate a hatch on the scrubber
vessel shell which is either above or below the internal component of
interest. Look for the problem listed below.
1. Packed-bed scrubbers
• Corroded or collapsed bed supports
• Plugged or eroded liquor distribution nozzles
2. Venturi scrubbers
• Eroded throat dampers
• Restricted throat damper movement due to solids deposits
Note: Safety conditions sometime preclude observations of internal
conditions. Respirators and other personal protection equipment should be
used even 1f the scrubber vessel has been purged out prior to the
observations.
6.6.1.2.16 Measure the outlet gas temperatures. This measurement is
conducted whenever it is necessary to determine if poor liquor-gas
distribution and/or inadequate liquor flow rate is seriously reducing
partlculate collection efficiency. The.steps in measuring the gas
temperature are outlined below.
6-50
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1. Locate safe and convenient measurement ports on the outlet
portion of the scrubber vessel shell or on the outlet ductwork of the
system. Often small ports of H to % 1n. diameter are adequate.
2. Attach a grounding/bonding cable to the probe if vapor, gas,
and/or partlculate levels are potentially explosive.
3. Seal the temperature probe in the port to avoid any air
infiltration which would result 1n a low reading.
4. Measure the gas temperature at a position near the middle of the
duct 1f possible. Conduct the measurement for several minutes to ensure a
representative reading. Some fluctuation 1n the readings is possible if
the probe is occasionally hit by a liquor droplet.
5. Compare the outlet gas temperature with the baseline value(s).
If the present value is more than 10°F higher, then either gas-liquor
maldistribution or inadequate liquor is possible.
6.6.2 Inspection of Dry Scrubbers
6.6.2.1 Dry Scrubber Inspection Overview.
6.6.2.1.1 Stack. >
1. Evaluate average opacities and puffing conditions as direct
indications of partlculate device operating problems.
2. The presence of a secondary plume 1s a direct Indication of severe
combustion problems or dry scrubber problems.
6.6.2.1.2 Continuous emission monitors.
Evaluate frequency and severity of excess emissions of parti.culate
matter, hydrogen chloride, sulfur dioxide, and nitrogen oxides from
monitor records.
6.5.2.1.3 Dry scrubber vessel.
1. Evaluate operating conditions which are indirectly related to the
acid gas removal efficiency. Most important of these is the outlet dry
bulb and wet bulb temperatures. Compare the present operating levels with
baseline values.
2. Evaluate inlet gas temperatures at present and variations of this
value since the last inspection. Low inlet temperatures could lead to
sol Ids buildup problems in spray dryer type system.
3. Determine if sol Ids recycle from the absorber vessel and/or the
partlculate control device is being used.
6-51
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4. Review records to evaluate frequency and severity of deviations
from normal operating conditions.
5. Evaluate corrosion problems which could lead to future excess
emission problems.
6.6.2.1.4 Alkaline reagent preparation.
1. Review maintenance records to evaluate efforts to maintain slurry
feed and density instruments.
2. Evaluate slaker (1f present) liquor outlet temperature as an
indirect Indication of the adequacy of calcium hydroxide slurry
preparation.
3. Evaluate procedures used to adjust dry scrubber operation to
various Incinerator loads and Inlet pollutant concentrations.
6.6.2.2 Level 4 Dry Scrubber Inspection. The Level 4 dry scrubber
inspection is a comprehensive inspection that includes all of the elements
of inspection Levels 1, 2, and 3. Table 6-5 provides a matrix of the
types of inspection activities included in each inspection level for air —
pollution control devices including dry scrubbers. The following j
paragraphs describe the inspection activities in detail and the matrix
points out differences between the different levels.
6.6.2.2.1 Dry scrubber and process system flowchart. A dry scrubber
system flowchart should consist of a simple block diagram that includes
the following elements.
1. Source(s) of emissions controlled by the system;
2. Locatlon(s) of any fans and blowers used for gas movement and
solids conveying;
3. Locations of any main stacks and bypass stacks;
4. Alkali preparation equipment, adsorber vessel or contactor,
part1culate control device, and recycle streams; and
5. Locations of major process instruments and gas stream continuous
monitors.
6.6.2.2.2 Identify potential safety problems. The identification of
potential safety problems is addressed in Section 6.3.2.
6.6.2.2.3 Evaluate locations for measurement ports. Evaluation of
locations for measurement ports is discussed in Section 6.3.3.
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6.6.2.2.4 Startup and shutdown procedures. The startup and shutdown
procedures used at the plant should be discussed to confirm the following.
1. The plant has taken reasonable precautions to minimize the number
of startup/shutdown cycles.
2. The dry scrubber is started up in a reasonable time after startup
of the process equipment. Inspectors should remember that starting the
atomizer (1n spray dryer type systems) when the inlet gas temperatures are
low can lead to absorber vessel deposits.
6.6.2.2.5 Dry scrubber system visible emissions. The evaluation of
visible emissilons is discussed in Section 6.3.4.
6.6.2.2.6 Condensing plume conditions. Condensing plume conditions
in dry scrubber systems are unusual since most vapor state species which
could cause such plumes are partially removed. The presence of a
condensing plume would indicate a major malfunction of the dry scrubber
system.
The principal characteristics of a condensing plume include a bluish-
white color, opacities which are higher when the weather is cold or very ;
humid, a low opacity at the stack discharge, and increasing opacities in
the first few seconds of plume travel.
6.6.2.2.7 Spray dryer absorber approach-to-saturation. One of the
most important operating parameters affecting the efficiency of a wet-dry
type dry scrubber is the approach-to-saturation. This is simply the
difference between the wet bulb and dry bulb temperatures measured at the
exit of the spray dryer vessel. The normal approach-to-saturation varies
between 90" and 180°F. The approach-to-saturation is monitored
continuously by a set of dry bulb and wet bulb temperature monitors. A
change in this value is sensed by the automatic control system which
either increases or decreases the slurry feed rate to the atomizer.
If there is significant question concerning the ability of the dry
scrubber system to maintain proper operation on a long-term basis, the
approach-to-saturation values indicated on the dry scrubber system daily
operating log sheets should be checked. Values much higher than baseline
values or permit stipulations indicate chronic problems such as:
1. Fouled absorber vessel temperature instruments;
2. Corrosion/scaling of absorber vessel atomizer;
6-53
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3. Corrosion/scaling of absorber gas dispersion equipment;
4. Low absorber vessel inlet gas temperatures during low load
periods;
5. Nozzle erosion or blockage; and
6. Slurry supply line scaling.
Due to the vulnerability of the temperature monitors to scaling and
blinding, Inspectors may find that some plants must occasionally bypass
the automatic process control system and operate manually for limited time
periods. Manual operation generally means slightly worse approach-to-
saturation values so that operators have a margin for error when sudden
process changes occur such as load changes. Gradually plants should be
able to increase the reliability of the temperature monitors by relocation
of the sensors and by Improved operation of the dryer.
Spray dryer absorber vessel dry bulb and wet bulb outlet gas
temperature measurements are taken if there is a significant question
concerning—the adequacy of the onsite gauges and if there are safe and
convenient measurement ports between the absorber vessel and the >
particulate control device. The measurements should be made at several
locations in the duct to ensure that the values observed are
representative of actual conditions. The values should be averaged and
compared with the value indicated by the onsite instruments (if
operational) and with baseline data sets. It should be noted that it is
rarely necessary to make this measurement since the onsite gauges are a
critical part of the overall process control system for the dry scrubber
system. Failure to maintain these instruments drastically increases the
potential for absorber vessel wall deposits and increased emissions.
These temperature monitors are normally very well maintained.
6.6.2.2.3 Spray dryer absorber reagent feed rates. The calcium
hydroxide (or other alkali) feed rates are important since they partially
determine the stolchiometric ratio between the moles of reagent and the
moles of acid gas. Low stoichiometric ratios result in reduced collection
efficiencies. Higher than needed stoichiometric ratios use excessive
reagent and may result in poor drying of the sorbent.
The reagent feed rate is generally determined using a magnetic flow
meter on the slurry supply line to the atomizer feed tank. The slurry
6-54
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density, another important operating parameter, Is monitored by a nuclear-
type density monitor. Typical slurry densities are in the range of 5 to
20 percent by weight. It should be noted that both the magnetic flow
meter and the nuclear density meter are vulnerable to scaling due to the
nature of the slurry.
Another way to determine the reagent feed rate is to record the feed
rates of new pebble lime and recycled solids indicated by the weigh belt
feeders. The weigh belt for the pebble lime is between the lime storage
silo and the slaker. The weigh belt feeder for the recycled solids is
close to the spray dryer absorber vessel.
The feed rates of makeup pebble lime and recycle sol Ids are generally
indicated on the daily operating logs of the dry scrubber system. Values
for the last 12 months should be compared with the corresponding
combustion load data to determine if significant changes in the overall
reagent stoichiometric ratios have occurred. Data concerning the system
load must be obtained from the combustion system daily operating log
sheets. If available, dry scrubber system inlet sulfur dioxide
concentrations also should be used in this qualitative evaluation of
reagent/add gas stoichiometrlc ratios.
6.6.2.2.9 Spray dryer absorber nozzle air and slurry pressures. For
units equipped with nozzles rather than rotary atomizers, the air
pressures and slurry pressures should be recorded and compared with
baseline levels. Some variation in the slurry pressures are necessary in
order to maintain proper approach-to-saturation values during combustion
system load variations.
6.6.2.2.10 Dry injection system feed rates. The long-term
performance of the calcium hydroxide supply system should be checked if
the emissions data indicates occasional emission excursions. The feed
rate of calcium hydroxide to the pressurized pneumatic system is generally
monitored by either a weigh belt feeder or a volumetric screw-type
feeder. Both of these feeders are located close to the calcium hydroxide
storage silos, and the feed rates are generally indicated on the main
system control panel. The feed rate data for the previous 12 months
provided by the weigh belt feeder or the volumetric screw feeder should be
compared against the combustion system loads and against the inlet acid
6-55
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gas concentration monitors (when available). The automatic control system
should be able to vary calcium hydroxide (or other alkali) addition rates
with load variations and inlet gas acid gas concentrations. Decreased
reagent feed rates indicate possible reductions in the stoichiometric
ratio and thereby a reduction in acid gas collection effectiveness. The
blower motor currents and the pneumatic line static pressures also should
be recorded and checked against baseline data sets. Higher motor currents
and higher conveying line static pressures indicate increases in the
airflow rates.
6.6.2.2.11 Calcium silicate feed rates. The Research Cottrell
semiwet/dry system utilizes a calcium silicate/calcium hydroxide dry
Injection system downstream from the calcium hydroxide spray dryer
absorber. The feed rate of calcium silicate/calcium hydroxide is
monitored by weigh belt feeders or volumetric screw conveyors. The
variability and reliability of the calcium silicate/ calcium hydroxide dry
injection system in Research-Cottrell systems should be evaluated by
reviewing the dally system operating logs. Some loss in acid gas >
collection efficiency could occur if feed rates were low.
6.6.2-.2.12 Control device solids recycle rates. The Teller
semiwet/dry system utilizes a-recycle stream from the fabric filter in
order to improve overall reagent utilization. The sol Ids recycle rate
during the inspection should be recorded and compared to baseline values.
The recycle rates used in the Research-Cottrell semiwet/dry type
systems have some impact on the overall acid gas collection efficiency.
Low recycle rates indicate slightly reduced acid gas collection
efficiency.
6.6.2.2.13 Dry scrubber system general physical conditions. While
walking around the dry scrubber and its inlet and outlet ductwork, check
for obvious corrosion around the potential cold spots such as the bottom
of the absorber vessel and the part1culate control device hoppers and
around the access hatches. Check for audible air infiltration through the
corroded areas, warped access hatches, and eroded solids discharge valves.
6.6.2.2.14 Slaker slurry outlet temperatures during past
12 months. The slaker slurry outlet temperature provides a rough
indication of the adequacy of the conversion from lime (calcium oxide) to
6-56
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calcium hydroxide. The temperatures should be compared to baseline
values. Improper slaking can result in poor reagent reactivity and
reduced acid gas collection efficiency.
6.6.2.2.15 Spray dryer absorber slurry flow rate and density monitor
maintenance records. The calcium hydroxide slurry monitors generally
consist of a magnetic flow meter and a nuclear density meter. Both of
these are sensitive to scaling especially when slurry densities are
high. The plant should have maintenance records for the monitors either
1n the form of completed work orders, a computerized maintenance record,
an Instrument maintenance log, or notes on the daily dry scrubbing
operations log. The records should be reviewed for the previous 12 months
whenever there is concern that there are periods of low slurry supply to
the atomizer.
6.6.2.2.16 Dry scrubber inlet gas temperatures. Dry scrubbing
systems have a limited turndown capability due to the need for complete
drying of the atomized slurry. Low gas inlet temperatures during periods
of low combustion system load can cause poor drying of the droplets. The >
process control system is generally designed to block atomizer operation
once inlet temperature drops below a preset value. The inlet gas
temperature data should be reviewed to confirm that the controller is
working properly, since operation under these conditions could lead to
absorber vessel deposits and nonideal operation once loads increase. The
inlet temperature data may be available on the dry scrubber system daily
operating logs, the archived continuous strip charts, or on the
computerized data acquisition file.
When the onsite gauge is not available, is malfunctioning, or is in a
potentially nonrepresentative location, the spray dryer absorber vessel or
dry injection system inlet gas temperature should be measured with a
portable thermocouple and monitor. For spray dryers, the measurement
should be taken in the main duct leading to the atomizer or in one or more
of the ducts that lead to the gas dispersion system within the vessel.
For dry injection systems, the measurement should be taken upstream of the
gas stream/reagent mixing point (such as the venturi contactor). The
measurements should be taken at several locations in the duct and
averaged. Locations near air infiltration sites should be avoided.
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6.6.3 Inspection of Fabric Filters
6.6.3.1 Fabric Filter Inspection Overview.
6.6.3.1.1 Stack.
1. Observe the average opacity and puffing conditions as a direct
indication of fabric filter performance.
2. Observe any secondary plume conditions since these indicate a
serious combustion problem and/or dry scrubbing problem.
6.6.3.1.2 Transmissometer.
1. Evaluate transraissometer physical condition prior to reviewing
opacity data.
2. Observe average opacity at the present time and for the last
8 hours to determine the representativeness of the inspection period.
3. Review average opacity records since the last inspection to
determine the frequency and severity of excess emission problems.
6.6.3.1.3 Fabric filter.
1. Evaluate fabric fi.lter pressure drop as an indirect indication of
bag blinding problems, bag cleaning problems, and gas flow changes. ;
2. Observe fabric filter physical condition as an indirect indication
of corrosion and air filtration.
3. Evaluate present inlet gas temperature to confirm that it 'does not
exceed the high temperature limitations of the fabric being used. Review
inlet gas temperature records since the last inspection to determine
frequency and severity of gas temperature excursion.
4. Evaluate fabric filter outlet gas temperatures as an indication of
air infiltration and possible fabric chemical attack. The outlet
temperature should be at least 20°F above the acid dewpoints. The gas
temperature difference across the fabric filter should be only 20° to 50°F
depending on ambient temperature, ambient wind speed, and the adequacy of
fabric filter insulation.
5. Listen for audible air infiltration around access hatches,
hoppers, and expansion joints.
6. Evaluate cleaning system operation to confirm that the bags are
being cleaned on a regular frequency and to identify any possible bag
problems due to nonideal cleaning conditions.
6-58
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7. Observe clean side conditions on units in which one or more
compartments can be isolated. Solids deposits are an indication of
emission problems. Physical condition of the bags and other components
are also observed to the extent possible without entering the fabric
filter.
8. Review bag failure rate and location records as a indirect
indication of fabric filter excess emission problems and of misguided
maintenance efforts.
9. Perform or observe "rip" tests (described below) as a rough
indicator of the reasons for frequent bag failures.
10. Observe cage conditions (pulse jet only) to determine possible
reasons for frequent bag failures.
6.6.3.2 Level 4 Fabric Filter Inspection
The Level 4 fabric filter inspection is a comprehensive inspection
that includes all of the elements of inspection Levels 1, 2, and 3.
Table 6-5 provides a matrix of the types of inspection activities included
in each Inspection level for air pollution control devices including
pulse-jet fabric filters. The following paragraphs describe the Level 4
pulse-jet fabric filter inspection activities 1n detail while the matrix
points out differences between the different levels.
6.6.3.2.1 Prepare a system flowchart. A fabric filter system
flowchart should consist of a simple block diagram that includes the
following elements.
1. Source(s) of emissions controlled by a single fabric filter;
2. Location(s) of any fans used for gas movement through the system
(used to evaluate inhalation problems due to positive static pressures);
3. Locations of any main stacks and bypass stacks;
4. Location of fabric filter; and
5. Locations of major instruments (transmissometers, static pressure
gauges, thermocouples).
6.6.3.2.2 Prepare a flowchart of the compressed air system. The
purpose of the flowchart is to indicate the presence of compressed air
system components that could influence the vulnerability of the pulse jet
fabric filter to bag cleaning problems. The flowchart should consist of a
simple block diagram showing the following components.
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1. Source of compressed air (plant air or compressor);
2. Air drier (if present);
3. Oil filter (if present);
4. Main shutoff valve(s);
5. Compressed air manifolds on fabric filter;
6. Drains for manifolds and compressed air lines;
7. Heaters for compressed air lines and manifolds; and
8. Controllers for pilot valves (timers or pneumatic sensors).
6.6.3.2.3 Evaluate locations for measurement ports. Evaluation of
locations for measurement points are discussed in Section 6.3.3.
6.6.3.2.4 Evaluate startup and shutdown procedures. The startup and
shutdown procedures used at the plant should be discussed to confirm the
following.
1. The plant has taken reasonable precautions to minimize the number
of startup/shutdown cycles.
2. The fabric filter system bypass times have been minimized.
3. The fabric filter system bypass times have not been limited to >
the extent that irreversible damage has occurred.
6.6.3.2.5 Identify potential safety problems. The identification of
potential safety problems is addressed in Section 6.3.2.
6.6.3.2.6 Evaluate the fabric.filter visible emissions. The
evaluation of visible emissions is discussed in Section 6.3.4.
6.6.3.2.7 Evaluate puffing conditions (pulse jet units only).
Evaluate the frequency and severity of puffs. These are often caused by
small holes in one or more rows of bags.
6.6.3.2.8 Evaluate condensing plume conditions. Condensing plume
conditions 1n fabric filters systems serving hospital waste incinerators
could conceivably be caused by partially combusted organic vapors or
hydrogen chloride vapors. The vaporous material condenses once the gas
enters the cold ambient air. Condensing plumes usually have a bluish-
white color. In some cases, the plume forms 5 to 10 feet after leaving
the stack. If the fabric filter operating temperature drops
substantially, this material can condense inside the fabric filter and
cause fabric blinding problems. Corrective actions must focus on the
incinerator or dry scrubber system.
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6.6.3.2.9 Measure the fabric filter static pressure drop. Fabric
filters operate with a wide range of static pressure drops (2 to 12 1n.
w.c.). It 1s preferable to compare the present readings with the baseline
values for this specific source. Increased static pressure drops
generally indicate high gas flow rates and/or fabric blinding and/or
system cleaning problems. Lower static pressure drops are generally due
to reduced gas flow rates, excessive cleaning intensities/frequencies, or
reduced Inlet partlculate loadings. The steps in measuring the stack
pressure with a portable pressure drop gauge are described below.
1. Locate safe and convenient measurement ports on the inlet and
outlet ductwork or on the fabric filter shell. In some cases it may be
possible to temporarily disconnect the onsite gauge in order to use the
portable gauge.
2. Clean any deposits out of the measurement ports.
3. If the Inlet and outlet ports are .close together, connect both
sides of the static pressure gauge to the ports and observe the static
pressure for 1 to 5 minutes.
4. If the ports are not close together, measure the static pressure
1n one port for 10 to 30 seconds and then proceed to the other port for 10
to 30 seconds. As long as the static pressure drop is stable the two
values can be subtracted to determine the stack pressure drop.
5. Under no circumstances should onsite plant Instruments be
disconnected without the explicit approval of responsible plant
personnel. Also, instruments connected to differential pressure
transducers should not be disconnected.
If the inspector does not have a portable pressure gauge, the fabric
filter static pressure drop should be recorded 1f the gauge appears to be
working properly. The gauge face should be clear of obvious water and
deposits. The gauge should fluctuate slightly each time one of the
diaphragm valves activates. These valves can be heard easily when close
to the pulse jet fabric filter. If there is any question about the gauge,
ask plant personnel to disconnect each line one at a time to see if the
gauge responds. If it does not move when a line is disconnected, the line
may be plugged or the gauge inoperable.
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6.6.3.2.10 Evaluate fabric filter general physical conditions.
While walking around the fabric filter and its inlet and outlet ductwork,
check for obvious corrosion around the potential "cold" spots such as the
corners of the hoppers, near the solids discharge valve, and the access
hatches. On negative pressure fabric filters, check for any audible air
infiltration through the corroded areas, warped access hatches, eroded
solids discharge valves, or other sites. On positive pressure fabric
filters, check for fugitive emissions of dust from any corroded areas of
the system.
6.6.3.2.11 Evaluate the clean side conditions when possible. If
there is any question about the performance of the fabric filter, request
that plant personnel open one or more hatches on the clean side (not
available on some commercial models). Note the presence of any fresh dust
deposits more than 1/8 in. deep since this indicates particulate emission
problems.
In the case of pulse jet fabric filters, also observe the conditions
of the bags, cages, and compressed air delivery tubes. The compressed air,-
delivery tubes should be oriented directly Into the bags so that the sides
of the bags are not subjected to the blast of cleaning air. The cages and
bags should be securely sealed to the tube sheet in units where the bag
comes up through the tube sheet. There should be no oily or crusty
deposits at the top of the bags due to oil 1n the compressed air line.
In some cases , operators will be unable to Isolate any compartments
without causing major gas flow problems with the incinerator and/or the
dry scrubber. Obviously, the request to check clean side conditions
should be withdrawn under such circumstances.
6.6.3.2.12 Evaluate compressed air cleaning system. The purpose of
checking the compressed air cleaning system is to determine if this
contributes to a significant shift in the fabric filter static pressure
drop and/or if this contributes to an excess emission problem. The
inspection procedures for the compressed air cleaning system can include
one or more of the following.
1. Record the compressed air pressure if the gauge appears to be
working properly. It should fluctuate slightly each time a diaphragm
valve 1s activated. Do not remove this valve since the compressed air
lines and manifold have high pressure air inside.
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2. Listen for operating diaphragm valves. If none are heard over a
10 to 30 minute time period, the cleaning system controller may not be
operating.
3. Check the compressed air shutoff valve to confirm that the line
1s open.
4. Count the number of diaphragm valves that do not activate during
a cleaning sequence. This can be done by simply listing for diaphragm
valve operation. Alternatively, the puff of compressed air released from
the trigger lines can sometimes be felt at the solenoid valve (pilot
valve) outlet.
5. Check for the presence of a-compressed air drier. This removes
water which can freeze at the inlet of the diaphragm valves. Also check
for compressed air oil filter.
6. Check for a drain on the compressed air supply pipe or on the air
manifold. This is helpful for routinely draining the condensed water and
oil In the manifold.
6.6.3.2.13 Confirm operation of cleaning equipment controllers.
Observe the fabric filter control panel during cleaning of one or more
compartments to confirm that the controller is operating properly. Each
compartment should be Isolated for cleaning before the static pressure
drop Increases to very high levels that preclude adequate gas flow. Also,
cleaning should not be so frequent that the bags do not build up an
adequate dust cake to ensure high efficiency filtration.
6.6.3.2.14 Measure inlet and outlet gas temperature. The primary
purpose of determining the present gas Inlet temperture is to evaluate
possible excess emission problems and/or high bag failure rate conditions
that can be caused by very high or very low gas inlet temperatures.
These measurements are conducted whenever it is necessary to
determine 1f air infiltration is causing fabric chemical attack due to
reduced gas outlet temperatures. A large difference between the baseline
temperature and the temperature measured during a subsequent inspection is
an indication that air infiltration is a problem. It also is helpful to
measure the inlet gas temperature to evaluate the potential for high gas
temperature damage to the bags. The average inlet gas temperature should
be 25° to 50°F below the maximum rated temperature limit of the fabric.
6-63
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Fifteen to 30 minute spikes of less than 25° F above the maximum rated
limit can usually be tolerated without fabric damage. The average inlet
gas temperature should be 25° to SOT above the acid gas dewpoint
temperature. For most commercial combustion processes, the acid dewpoint
is usually between 225° to 300°F. The inlet gas temperature also should
be above the water vapor dewpoint. The steps in measuring the gas
temperature are outlined below.
1. Locate safe and convenient measurement ports on the inlet and
outlet ductwork of the collector. Often small ports less than % in.
diameter are adequate. Measurements using ports on the fabric filter
shell often are inadequate since moderately cool gas is trapped against
the shell.
2. Attach a grounding/bonding cable to the probe if vapor, gas,
and/or particulate levels are potentially explosive.
3. Seal the temperature probe in the port to avoid any air
infiltration that would result in a low reading.
4. Measure the gas temperature at a position near the middle of the
duct 1f possible. Conduct the measurement for several minutes to ensure a
representative reading.
5. Measure the gas temperature at another port and compare the
values. On combustion sources, a gas temperature drop of more than 20° to
40°F indicates severe air infiltration.
6. Compare the inlet gas temperature with the maximum rated
temperature limit of the fabric present. If the average gas temperature
is within 25° to 50°F of the maximum, short bag life and frequent bag
failures are possible. Also, if there are short-term excursions more than
25° to 50°F above the maximum temperature limits, irreversible fabric
damage may occur.
Locate any onsite thermocouples mounted on the inlet to the fabric
filter. If this instrument appears to be in a representative position,
record the temperature value displayed in the control room.
6.6.3.2.15 Evaluate the fabric filter gas temperature records. The
purpose of reviewing continuous temperature recorder data is to determine
if temperature excursions contribute to excess emission problems and/or
high bag failure rates. Review selected strip charts to determine if the
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gas Inlet temperatures have been above the maximum rated fabric
temperature or below the acid vapor or water vapor dewpoints.
6.6.3.2.16 Perform fabric rip test and review fabric laboratory
analyses. The purpose of evaluating fabric condition is to determine if
any corrective actions planned by the owner/operators have a reasonable
probability of reducing frequent excess emissions.
To perform a rip test, ask the plant personnel for a bag that has
been recently removed from the fabric filter. Attempt to rip the bag near
the site of the bag hole or tear. If the bag cannot be ripped easily,
then the probable cause of the failure is abrasion and/or flex damage.
These bags can usually be patched and reinstalled. If the bag can be
ripped easily, then the fabric has been weakened by chemical attack or
high temperature damage. Weakened bags should not be patched and
reinstalled. It may be necessary to Install new bags throughout the
entire chamber if the bag failure rates are high.
6.6.3.2.17 Evaluate bag failure records. The purpose of reviewing
bag failure records 1s to determine the present bag failure rate and to ;
determine 1f the rate of failure is increasing. Plot the number of bag
failures per month for the last 6 to 24 months. If there has been a
sudden Increase, the owner/operators should consider replacing all of the
bags 1n the compartment(s) affected. If there 1s a distinct spatial
pattern to the failures, the owner/operators should consider repair and/or
modification of the internal conditions causing the failures.
6.6.3.2.18 Evaluate the bag cages. The bag cages are evaluated
whenever there are frequent abrasion/flex failures at the bottoms of the
bags or along the ribs of the cage. Ask the plant personnel to provide a
spare cage for examination. There should be adequate support for the bag
and there should not be any sharp edges along the bottom cups of the
cage. Also check the cages for bows that would cause rubbing between two
bags at the bottom of the fabric filter.
6.6.3.2.19 Evaluate the inlet and outlet gas oxygen levels. These
measurements are performed to further evaluate the extent of air infiltra-
tion. An increase of more than 1 percent oxygen going from the inlet to
the outlet indicates severe air infiltration (e.g., inlet oxygen at
6.5 percent and outlet oxygen at 7.5 percent). The steps involved in
measuring the flue gas oxygen levels are itemized below.
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1. Locate safe and convenient measurement ports. Generally, the
ports used for the temperature measurements are adequate for the oxygen
measurements.
2. Attach a grounding/bonding cable to the probe 1f there are
potentially explosive vapors, gases, and/or partlculate.
3. Seal the probe to prevent any ambient air Infiltration around the
probe.
4. Measure the oxygen concentration at a position near the center of
the duct to avoid false readings due to localized air Infiltration. The
measurement should be repeated twice 1n the case of gas absorption
instruments. For continuous monitoring instruments, the measurement
should be conducted for 1 to 5 minutes to ensure a representative value.
5. If possible, measure the carbon dioxide concentration at the same
locations. The sum of the oxygen and carbon dioxide concentrations should
be 1n the normal stoichiometric range for the fuel being burned. If the
sum is not in this range, a measurement error has occurred.
6. As soon as possible, complete the measurements at the other ^
port. Compare the oxygen readings obtained. If the outlet values are
substantially higher, severe air infiltration Is occurring.
6.7 REFERENCES FOR CHAPTER 6
1. U. S. Environmental Protection Agency. EPA Guide for Infectious
Waste Management. Office of Solid Waste. Washington, D.C.
Publication No. EPA/530-SW-86-014. May 1986. p. ix.
2. Ibid. p. 3-7.
3. Hospital Waste Combustion Study: Data Gathering Phase. Final
Report. U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, North Carolina.
EPA-450/3-88-017. December 1988. p. 3-10 to 3-24.
4.
5.
6.
7.
8.
Ibid.
Ibid.
Ibid.
Ibid.
Ibid.
P-
P-
p.
P-
P-
3-6.
3-20.
1-9.
3-16.
3-4.
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9. Ibid. p. 3-20.
10. Ibid. p. 1-13.
11. McCree, R. E. Operation and Maintenance of Controlled Air
Incinerators. Ecolaire Environmental Control Products, Inc.
Charlotte* North Carolina.
12. Reference 3. p. 1-11, 12.
13. Reference 1. p. 3-9.
14. Reference 1. p. 3-12.
15. Reference 11. p. 10.
16. Richards, J. Municipal Waste Incinerator Field Inspection Notebook
(Draft); Prepared for U.S. EPA.
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7.0 SPECIAL CONSIDERATIONS
7.1 INCINERATOR OPERATOR TRAINING AND OPERATOR EXPERIENCE
The success of incineration as a technique for treating hospital
waste depends on the proper operation of the incinerator and its
associated air pollution control device. Proper operating techniques can
affect equipment reliability, on-line availability, combustion efficiency,
and regulatory compliance with air pollution regulations. The operator is
in control of many of tha factors that have an impact on the performance
of a hospital waste incinerator and air pollution control device
including: (1) waste charging procedures, (2) incinerator startup and
shutdown, (3) air pollution control device startup and shutdown,
(4) monitoring and adjusting operating parameters for the incinerator and
air pollution control system, and (5) ash handling. Poorly trained and/or
inexperienced operators have neither the knowledge nor the skills to
operate the equipment properly or react appropriately to upset
conditions. Therefore, the value of appropriate operator training and/or j
experience should be apparent to the inspector.
Typically, incinerator and air pollution control device manufacturers,
once their equipment is installed, offer a hands-on operator training
program that includes instruction in the proper operating procedures and
the necessary preventive maintenance activities that should be
performed. While this training is desirable, it is often lost when the
operator decides to take another, higher paying job. Operator turnover is
experienced by many hospitals and causes problems in maintaining proper
operation of equipment and necessitates almost continual training of
operators. Turnover and proper operation are particular problems at
hospitals where housekeeping personnel operate the incinerator system
because their level of understanding of the combustion process is limited,
their level of commitment to proper operation is low, and the tendency to
move to other, higher paying jobs is high. One solution to these problems
is to create a dedicated position where one employee operates the
•incinerator and air pollution control device and is more highly paid than
housekeeping personnel. This tends to reduce the turnover thereby
producing a more experienced operator.
7-1
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At most hospitals, a hospital engineer is in charge of the operation
and maintenance of the incinerator. The engineer should have a good
working knowledge of the incinerator and should be able to provide some
operator training in the proper operational procedures. Additionally, the
facility engineer should ensure that preventive maintenance activities are
carried out on a regular basis to minimize operational problems and
downtime. Some States have included specific requirements for operator
training in proposed regulations for infectious waste incinerators.
The inspector should be aware of the above considerations. He/she
should inquire as to the experience level of the operator, the amount of
hands-on training the operator has received, and the availability of a
hospital engineer to direct the operator as required. The inspector
should evaluate whether the operator meets the necessary training
requirements (where applicaole).
7.2 EMERGENCY OPERATING PLAN
The permit for the incineration facility may stipulate that an
emergency operating plan be developed and implemented to prevent exposure ,
of the public or operate'" personnel to spills or leaks of infectious
wastes. In general, most plans should include the responsible individual
to be notified in case of an emergency, emergency contacts (such as fire
departments) and procedures to be followed in the case of an emergency.
The inspector should become familiar with the permit-stipulated
requirements for an emergency operating plan prior to the inspection.
During the inspection, the insDector should ask to see the plan (if
applicable). The plan should be reviewed to ensure that all stipulated
requirements are addressed. The inspector should also ensure that the
plan is accessible to operator personnel and that they are familiar with
its requirements.
7.3 CROSS-MEDIA INSPECTIONS
Hospital incinerators are potentially subject to two environmental
media regulatory programs. These are air pollution and solid waste. If a
wet scrubber is used for pollution control, water discharge also is of
concern.
7-2
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7.3.1 Air Pollution
The Agency's authority, regulations, and inspection procedures under
the Clean Air Act are discussed earlier in this manual.
7.3.2 Solid Waste
7.3.2.1 Resource Conservation and Recovery Act: Section 3007 of the
Resource Conservation and Recovery Act (RCRA) allows a duly authorized
inspector:
1. To enter at reasonable times any establishment or other place
maintained by any person where hazardous wastes are generated, stored,
treated, disposed of, or transported from; and
2. To inspect and obtain samples from any person of any such waste
and samples of any containers or labeling of such wastes.
As a first step in fulfilling the Congressional mandate to establish
a hazardous waste management system, EPA published proposed regulations in
the Federal Register on December 13, 1973, wnich included a proposed
definition and treatment methods for infectious wastes.' During the
public comment period for this rulemaking, EPA received approximately _,
60 comments which specifically addressed the infectious waste provisions
of the proposed regulations.'
On May 19, 1980, EPA published the first phase of the hazardous waste
regulations. The Agency stated in the preamble to the regulations that
the sections on infectious waste would be published when work on
treatment, storage, and disposal standards was completed. While the
Agency has evaluated management techniques for infectious waste,
considerable evidence that these wastes cause harm to human health and the
environment is needed to suoport Federal rulemaking.J While EPA has not
yet promulgated rules for infectious wastes, guidance on handling,
treatment, and disposal of infectious wastes is provided in EPA Guide to
Infectious Waste Management.J
7.3.2.2 State Regulations for Solid Waste. Over 25 States have'
passed hazardous waste legislation specifically to control the treatment,
storage, and disposal of infectious waste (as part of their hazardous
^aste management program). Some States have already promulgated
regulations controlling infectious waste, while other States are preparing
such regulations. Because there is no unanimity of opinion on the hazards
7-3
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posed by infectious waste and appropriate techniques for safe disposal of
these wastes, control requirements vary from State to State.
7.3.3 Inspector Multimedia Resoonsibilities
In addition to the air pollutant emission concerns, an inspector
snould be cognizant of the solid waste handling requirements that may be
associated with the incineration facility.
Of particular concern are wastes that may be regulated as hazardous
under Subtitle C of RCRA. Table 7-1 lists the types of Subtitle C wastes
(i.e., F, U, or P wastes) that may be generated at a medical facility. A
facility is determined to be a hazardous waste generator if it generates
more than ICO kg per calendar month of hazardous waste. The facility must
comoly with the requirements of 40 CFR Parts 262 through 265, 268, 270,
and 124 and the notification requirements of Section 3010 of RCRA. These
regulations include specific requirements for generators, transporters,
and owners/operators of hazardous waste treatment, storage, and disposal
facilities. These requirements also are applicable to generators of
greater than 1 kg of acute hazardous waste or "P" waste per calendar
month. If a facility generates ICO kg of Subtitle C waste and 1 kg or
less of P waste per calendar month cr less, then the facility is called a
conditionally exempt small quantity generator and is not subject to the
aforementioned requirements. In order to prove that a facility is a small
quantity generator, it must keep detailed records of the types and
quantities of hazardous waste generated, and where, when, and by whom it
rt-as disposed. However, small quantity generators are exempt from the
manifest requirements for generators described in 40 CFR Part 262. In
order to burn any of the Subtitle C Bastes in an onsite incinerator, the
incinerator must be permitted to burn the wastes under 40 CFR 270 (EPA
Adminstered Permit Programs: The Hazardous Waste Permit Program) or must
be licensed or permitted by the State to burn waste. The inspector should
cneck the waste generation records and appropriate permit if he/she
suspects that hazardous waste is being improperly disposed in the
^ncinerator.
In many States, the treatment, storage, and disposal of infectious
.vaste will be subject to State regulations or permit conditions. At the
initial Level 4 inspection, the inspectors should obtain copies of any
7-4
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TABLE 7-1. LIST OF HAZARDOUS WASTES THAT MAY BE
GENERATED AT A MEDICAL FACILITY
F Wastes3 U Wastesb P Wastes0
F003d U206 - Streptozotocin None
U010 - Mytcmycin C
FC05e U150 - Melphalan
U059 - Daunomycin
U058 - Cyclophosphamide
U0237 - Uracil Mustard
U035 - Chlorambucll
U015 - Azeserine
U026 - Chlornaphazine
U140 - Isobutyl Alcohol
U151 - Mercury
U044 - Chloroform
U002 - -cetone
U122 - Formaldehyde
U220 - Toluene
U239 - Xylere
^Hazardous wastes from nonspecific sources.
"Toxic hazardous wastes.
^Acute hazardous wastas.
Scintillation wastes using xylene as a solvent would be included in this
category.
e$cintillation wastes using toluene as a solvent would be included in this
category.
7-5
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State or Federal solid-waste-related permits or regulations that pertain
to the incinerator waste feed material or incinerator residue ash. Prior
to any subsequent inspections, the inspector should become familiar with
the conditions of the permits or regulations. During the inspection, the
inspector should identify any deviations from the regulations or permit
conditions. These deviations should be documented in the inspection
report. All supporting data or photographs should also be recorded and
identified for possible followuo activities. After the inspection, the
inspector should report all observed environmental problems to his or her
immediate supervisor for notification of the appropriate Federal or State
agency.
7.4 STARTUP AND SHUTDOWN PROCEDURES FOR HOSPITAL WASTE INCINERATORS AND
ASSOCIATED AIR POLLUTION CONTROL DEVICES
Because each incinerator model is designed differently, design
criteria, operating parameters, and operating procedures will vary. This
kind of variation applies to the startup and shutdown procedures
associated with the different incinerator types. Therefore, a discussion
of the proper execution of these procedures is provided below on each of
the incinerator types discussed in Chapter 5. Additionally, general
discussions are presented on the proper startup and shutdown procedures
for wet scrubbers, dry scrubbers, and fabric filters. The inspector
should be well versed in the startup and shutdown procedures for all of
these types of equipment because emissions can be the highest during
startup and shutdown. The inspector should observe these procedures,
especially startup, during the inspection if at all possible.
Special concerns during startup include the following:
1. Assuring that all air pollution control equipment is online and
properly operating prior to initiating waste charging; and
2. Assuring that the secondary combustion chamber is preheated and
above a minimum acceptable operating temperature before charging (or
igniting for batch feed systems) waste.
7.4.1 Batch Feed__Starved-Air Incinerator
This type of incinerator, typically, is a small unit with a capacity
that may range up to 500 Ib/h but is more typically less than 200 Ib/h.
The incinerator is operated in a "batch-mode," which entails a single
7-6
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charge at the beginning of the operating cycle, followed by combustion,
ash burnout, cool down, and ash removal over a 12- to 24-h period. The
following sections describe the startup and shutdown procedures for a
batch feed starved-air incinerator.
7.4.1.1 Startup. Startup of the incinerator actually begins with
removal of the ash generated from the previous operating cycle. The
following are guidelines for good operating practice:3
1. Ths incinerator should be allowed to cool sufficiently so that it
"is sar~2 for the operator to remove the ash. This cooling can take as long
as 8 h.
2. The operator should exercise extreme caution since the refractory
may still be hot and the ash may contain local hot spots, as well as sharp
objects.
3. The ash and comcusticn cnamoer should not be sprayed with water
to cool the chamber because rapid cooling from water sprays can adversely
affect the refractory.
4. A flat blunt shovel, not sharp objects that can damage the
refractory material, should be used for cleanup.
5. Avoid pushing ash into the underfire air ports.
6. Place the ash into a nonccmbustable heat resistant container,
i;e., metal. Dampen the ash with water to cool and minimize fugitive
emissions.
7. Assure that the ash door is securely closed and the integrity of
the seal is maintained after ash removal is completed.
Prior to initiating charging, operation of the ignition and secondary
burners and combustion air blowers should be checked. The incinerator is
charged cold. Because these units generally are small, they are usually
manually loaded. The waste is loaded into the ignition chamber, which is
filled to the capacity recommended by the manufacturer. Typically, the
manufacturer will recommend filling the incinerator completely, but not
overstuffing the chamber. Overstuffing can result in blockage of the air
port to the combustion cnamoer and in premature ignition of the waste and
poor performance (i.e., excess emissions) during startup. Overstuffing
also can result in blockage of the ignition burner port and damage to the
burner. After charging is completed, the charge door is closed, the seal
7-7
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visually checked for irregularities, and the door is locked. Once
operation is initiated, no further charges will be made until the next
operating cycle is initiated, i.e., after cooldown and ash removal.
Prior to ignition of the waste, the secondary combustion chamber is
preheated to a predetermined temperature by igniting the secondary
burner. A minimum secondary chamoer temperature of 1600CF is recommended
prior to ignition of the waste. Preheat takes from 15 to 60 minutes.'1
After the secondary charmer is preheated, the secondary combustion
air blcwer is turned on to provide excess air for mixing with the
cc.TDUsticn gases from the ignition chamber.
The ignition chamber ccmousticn air blcwer is activated and the
primary burner is ignited to initiate waste combustion. When the primary
chamber reaches a preset temperature and the waste combustion is self-
sustaining, the primary burner is shut down. A typical temperature is
1 i rin°F
i. -t --> -./ i •
The primary comcusticn air and secondary ccmoustion air are adjusted
to maintain the desired primary and secondary chamber temperatures.
(Typically, this adjustment is automatic and can encompass switching from
high to low settings or complete modulation over an operating range.)
During operation, the primary burner is reignitad if the ignition
chamber temperature falls below a preset temperature. Similarly, the
secondary burner is reduced to its lowest firing level if the secondary
chamoer rises above a preset high-temperature setting. Again, control of
the burners, like the combustion air, is typically automated. A
Darcmetric damper on the stack is used to maintain draft. The incinerator
chambers should both be maintained under negative draft.
7.4.1.2 Shutdown. After the waste burns down and all volatiles have
been released, the primary chamonr ccmoustion air level is increased to
facilitate complete combustion of the fixed carbon remaining in the ash.
The temperature in the primary chamber will continue to decrease
indicating combustion is complete. A typical burndown period is 2 to
4 h.° When combustion is complete, the secondary burner is shut ^own.
Shutdown of the secondary burner, which initiates the cooldown
period, usually is automatically controlled to occur at a preset length of
time into the cycle."' The combustion air blowers are left operating to
7-8
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cool the chambers prior to subsequent ash removal. The blowers are shut
down when the chambers are completely cooled or prior to opening.the ash
door for ash removal. Cooldown typically lasts 5 to 8 h.°
As described in Chaster 3, appropriate safety precautions should be
taken when removing ash from the incinerator including the use of
protective clothing, thick rubber or plastic gloves, eye protection, and a
respirator or dust mask filter. The ash should be gently removed with a
rake and blunt shovel to prevent fugitive dust emissions and to prevent
damage to the refractory.
The final step in the cycle is examination of ash burnout quality.
Inspection of the ash is one tool the operator and inspector has for
evaluating incinerator performance.
7.4.2 Intermittent-Duty. Starved-Air Incinerators
Intermittent-duty, starved-air incinerators typically are used for
"shift" type operation. The incinerator must be shutdown routinely for
ash removal. Hence, there is a distinct operating cycle. The main
feature which distinguishes tnis type of incinerator from the batch
incinerator is the charging procedures which are used. The charging
system is designed to accommodate multiple charges safely throughout the
operating cycle rather than to rely on a single batch charge at the
beginning of the operating cycle. Either manual or automated charging
systems can be used.
7.4.2.1 Startup. The residual ash from the previous operating cycle
must be removed before a cycle can ce initiated. Ash removal procedures
are essentially the same as those described in Section. 7.5.1.1 for batch
mode incinerators.
Before the operator initiates startup, proper operation of the
primary and secondary burners and combustion air blowers should be
checked. The following steps are conducted during startup:
1. The primary and secondary burner(s) are ignited, and preheat of
the combustion chambers is initiated;
2. The secondary chamber must reach a predetermined temperature
(e.g., 1400°F) before the incinerator is ready for charging. A minimum
warmup time of 30 to 60 minutes is recommended; and
3. After the predetermined secondary chamber temperature is
7-9
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attained, the primary and secondary combustion air blowers are
activated. The incinerator is ready to be charged.
Stable combustion can be maintained most readily with a constant
thermal input to the incinerator. Feeding too much waste in a charge
causes the incinerator to overload. These overloads can result in poor
burndown (because of waste pile buildup on the hearth) or can cause
excessive emissions because the rapid generation of volatiles overloads
the caoacity cf the secondary chamber. Feeding too little waste results
in inadequate thermal input and consequent excessive auxiliary fuel
use.3 The reccoriended charge frequency and quantity is 15 to 25 percent
of ths rated capacity (Ib/h) at 10- to 15-minute intervals.5' Another
rule cf thi;r.iD is to recharge the incinerator after the previous charge has
been reduced by 50 to 75 percent in volume.J Charging volume and
frequency will vary with waste composition, and the operator must use scrne
judgment to determine appropriate rates. Monitoring the temperature
profile of the combustion chambers will assist the operator in determining
the proper charging rates.
After the last cnarge of the day is completed, the incinerator is set
to initiate the burndown cycle. The limiting factor on how long the
charging period can be sustained without initiating the burndown cycle is
the degree of ash buildup on the hearth. Typically, the charging period
is limited to 12 to 14 hours.0
7.4.2.2 Shutdown. The burndown cycle is essentially the same as
that described for batch incinerators and is initiated after the last
charge of the day is made. For intermittent-duty incinerators, the
burndcwn sequence can be initiated manually or automatically.
7.4.3 Continucus-Cuty, Starved-Air Incinerators
Continuous-duty incinerators have the capability of continuously
removing the ash from the incinerator hearth. Consequently, the
incinerator can be operated at a near-steady-state condition by
continuously charging the unit at regularly timed intervals and,
similarly, by removing the ash at regularly timed intervals.
7.4.3.1 Startup. Startup procedures for continuous-duty
incinerators are essentially the same as those for the intermittent-duty
J
7-10
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incinerators. Tha chambers are first preheated before the initial charge
is loaded to the incinerator.
7.4.3.2 Shutdown. Shutdown of the incinerator involves stopping the
charging process and maintaining temperatures in the ccmDustion chamber
until the remaining waste burns down to asn and is finally discharged from
the system in the normal manner.
7.4.4 Excsss-AJr Incinerators
Ir.cir.aratcrs operating at sxcass-air levels in the primary chamber
^
likaly will ba used only for Type 4 (anatomical) wastes." Type 4 wastes
have a'fairly consistent composition, contain high moisture levels, and
have a lev/ Stu value. Hide variations in Btu content are not expected,
ard the corncustion rate can be well controlled at excess-air levels. The
incinerator is coeratad at high primary ccmoustion chamber temperatures
3
rfith constant use of auxiliary burners."
Typical applications include batch cr intermittent operation;
continuous-duty operation ,vith automatic asn removal is atypical. Startup
and shutdown of excess-air/pathological waste incinerators are briefly ,,
discussed in this section.
7.4.4.1 Startup. Startup of tha excess-air incinerator is similar
to startup for the batch-mode, starvsd-air incinerators. The secondary
chamber is first preheated to a predetermined chamber temperature. The
incinerator is then charged with the waste.
The waste is cnarged to the ignition chamber prior to burner ignition
or preheat of the ignition cnamoer. The waste is placed on the hearth in
a manner to provide maximum exposure to the primary chamber burner
flame. Consequently, placing several components of the charge one on top
of the other is not goc.d practice. The charging door is closed, and the
primary burner ignited.
Additional charges, if any, are made only after the previous charge
has been significantly reduced in volume. The primary burner is shut off
before the charge door is opened. If necessary, the ash bed is stoked
before the new charge is added. After the new charge is added, the door
is closed and sealed and the primary ourner reignited.
7.4.4.2 Shutdown. There is no burndown period in the operation of
excess-air/pathological incinerators. The degree of burnout achieved is
7-11
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dictated by the length of time that the primary burner is left in
operation. After complete destruction of the waste has been achieved (as
noted by visual observation through a viewport), the primary burner is
shutdown. The secondary burner is not shut off until all smoldering from
residual material on the hearth in the primary chamber has ceased. After
all smoldering in the ignition chamber has ceased, the secondary burner is
shutdown, and the incinerator allowed to cool. Once the incinerator is
ccol, the £5n residue is manually removed by shoveling and/or raking.
7.4.5 Wet ScruPeers
Prcoer operation of a scruober requires that the operator
(1) establish a fixed liquid flow rate to the scrubbing section,
(2) initiate gas flew through the system by starting a fan, and (3) set up
the liquid recirculaticn system so that suspended and dissolved solids
buildup does not create operating prcnlems. Cnce the system has been
started and operation has staoilized, little additional operator attention
will be needed, other than for routine operation and maintenance
activities. Operators should refer to the instruction manual provided by ••'
the scrubber manufacturer for adjustment of site-specific operating
condi tions.
7.4.5.1 Startup. The following sequence must be adhered
to during startup of a scrubbing system to ensure proper operation:
1. Turn on the liquid recirculation system or liquid supply(s) to
the scrubber(s) and mist eliminator.
2. Adjust the liquid flc// rates to those specified in the
instructions supplied by the scrubber manufacturer.
3. If the induced draft or forced draft fan feeding the scrubbing
system has a damper installed at its inlet or cutlet, close the damper.
4. Start the induced draft or forced draft fan feeding the scrubbing
system.
5. If the system is equiooed with a damper, gradually open the
damper until the proper gas flow rate is established.
6. Again, recheck the liquid flow rate(s) and adjust as necessary.
7. Check the differential pressure across the scrubber and compare
with the design pressure drop specified in the manual. If the pressure
drop is too high, either the liquid flow rate or the gas 'flow rate is too
7-12
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high. If the system is equipped with a damper, close the damper off
slightly until the differential pressure reaches the proper level, or if
it is not possible to decrease gas flow rates, decrease the liquid flow
rate to the scrubber until the proper differential pressure is
established. If the differential pressure is too low across the scrubber,
either the liquid rate is too lew or the gas flow rate is too low. To
correct this condition, either increase the gas flow rate by opening a
damoar, or increase the liquid flew rate to trie scrubber.
3. Initiace the liquid bleed to treatment or disposal, as specified
in the manufacturer's manual. If the bleed is taken by an overflow from
the recirculation tank, the flew rate at this point is establishech by the
rate at which ma.'ouo water is introduced to the recirculation tank. The
manufacturer's manual should show the anticipated water evaporation rate
in the scrubbing system, If, as an example, the evaporation rate is
1 gallon cer minute, and if you wish to estaolish a oleed rate of 1 gallon
""per minute, it will be necessary to feed 2 gallons per minute of total
water to the recirculation tank. The bleed rate is determined by the rate.'
at which :he solids build up in the scruboing system. These solids can be
either suspended or dissolved solids or octh. A scrubber is capable of
handling a maximum of 3 percent (weight) suspended solids, and it is
suggested that the dissolved solids not exceed 10 percent (weight). Based
on design data, a recommended bleed rate from the system should be
provided by the manufacturer. The operator should combine this figure
^ith the evaporation figures to give a total recommended makeup water rate
to the recirculaticn tank if an overflew type bleed system is used. If a
bleed system is provided from a slip stream off the pump feeding the
venturi scrubber, liquid makeup is normally provided by a level control
device in the recirculation tank. The flew rate required will be the same
as the flow rate required for the overflow bleed system. However, it is
only necessary to ensure that adequate water supply is available to the
level control device on a continuous basis.
7.4.5.2 Shutdown. To shut the system down without overloading the
fan or causing any damage to the scrubbing equipment, the following
procedures should be adhered to:
7-13
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1. Shut off the induced draft or forced draft fan feeding the
scrubbing system.
2. Wait until the fan impeller has stopped rotation and shutoff the
scrubbing water racirculation pump.
3. Shut off the makeup water supply system.
7.4.6 Dr Sc rubers
Dry scrubbers either inject an alkaline slurry, which is subsequently
dried by the hot flue gas, or a dry alkaline powder into the flue gas
stream for acid gas control. Problems associated with startup and
shutdown of dry scrubbers are directly related to excess moisture in the
system. Excessive moisture refers to condensed water vapor and is a
function of the moisture content, temperature, and resulting saturation of
the flue gas in the system. Condensed water creates problems with solids
Buildup due to the hygrosccoic nature of the alkaline sorbent materials
and corrosion due to the corrosive nature of the salts, such as calcium
chloride, resulting from the acid/alkaline neutralization reactions.
Proper startup and shutdown procedures are intended to prohibit the
condensation of water vapor in the presence of the alkaline sorbent or the
reaction D *" c d u r"t~ salts.
7.4.6.1 Startup. Prevention of condensation during startup can be
achieved by bringing the temperatures of the incinerator and flue gas up
to normal operating levels before injection of the slurry or dry sorbent.
Ideally, auxiliary fuel firing should be utilized to achieve these temper-
atures before charging witn wastes to prevent uncontrolled emissions of
acid gases. If the incinerator is started up with waste feed material,
slurry feed should be regulated to provide a minimum wet bulb/dry bulb
temperature difference of 90° to 100°F. This temperature differential
will prevent condensation and will allow efficient removal of the acid gas.
7.4.6.2 Shutdown. At shutdown the system will eventually cool down
to ambient temperature. If the temperature cools below the saturation
temperature, condensation will occur. The approach to preventing solids
buildup and salt corrosion at shutdown should be to eliminate, as much as
possible, the alkaline sorbent materials and reaction products from the
system before saturation temperatures are reached. Sorbent injection
should be terminated and the exhaust system allowed to purge itself of all
7-14
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sorbent and reaction products before the temperature cools to the
saturation point. To achieve this goal, auxiliary fuel-firing should be
utilized to maintain a minimum wet bulb/dry bulb temperature difference of
90° to 1CO°F until all waste are ccmousted. The auxiliary fuel firing
should be continued long enougn to maintain flue gas temperatures above
saturation until the system is purged of sorbent and reaction products.
Purging of the system should include a ccrnolete cleaning cycle for the
fioric filter before the system is allowed to cool. If the alkaline
filter cake is retained on the Dags, condensation can result in blinding
of the bags.
7.4.7 Fabri c F i1 ters
Uhile the performance of a fabric filter is dependent on proper
design, raccrdkaeping practices, and the timely detection of upset
conditions, prooer operation and preventive maintenance procedures are
necessary.to ensure satisfactory, long-term oerfcrmance. This section
discusses general ccarating procedures that can minimize unexpected
malfunctions and improve the performance of the fabric filter. Preventive.'
maintenance practices are discussed in Chapter 4. Proper operating
procedures are important during startup, normal operation, shutdown, and
emergency conditions.
7.4.7.1 Startup. Prior to operation of a new fabric filter, all
components including the cleaning system, tha dust-discharge system, and
the isolation dampers and fans should undergo a complete check for proper
operation. Clean ambient air should be passed through the system to con-
firm that all bags are properly installed. New bags are prone to abrasion
if subjected to high dust loadings and full-load gas flows, particularly
during the initial startup before the bags have the benefit of a dust
buildup caka to protect the fibers from abrasion or to increase their
resistance to gas flow. Full gas flow at high dust loadings can allow the
particulate matter to impinge on the fabric at high velocity and result in
abrasion that may shorten bag life. In addition, the dust may penetrate
so deeply into the fabric that the cleaning system cannot remove it, and a
"permanent" pressure drop results. Bag abrasion may be prevented by
either (1) operating the incinerator at a low throughput and reduced gas
volume to allow the dust cake to build gradually or (2) precoating the
7-15
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bags to provide a protective cake before the incinerator exhaust is intro-
duced. Praccat materials may include either flyash or pulverized limestone,
If the fabric filter is ccerated at temperatures below the dewpoint
of water and/or the hydrochloric acid formed by the combustion of
chlorinated elastics, serious operating problems may arise. Warm, moist
gas that is introduced into a cool or cold fabric filter will cause
condensation on the bags or on the fabric filter shell. Condensation can
causa a condition kr.cwn as ''mudded" bags where the bags are blinded by
dust ard moisture. The acid de-vooint depends on the amount of moisture
and acidic material in the gas stream. Condensation of acid can cause
corrosion of the fabric filter components, sticky particulate and cake-
release problems, and acid attack on seme fabrics. Preheating the fabric
filter to a temnerature aoova the acid dewpoint will prevent condensation
and enhance fabric filter performance. Because the incinerator goes
through a warmuo period using natural gas or fuel oil burners prior to
waste ccmoustion, tna problems associated with condensation of water or
hydrochloric acid are unlikely to occur. If sufficient heat in the fabric.,-
filter collector is not cotained from the incinerator auxiliary burner
during startup, than additional auxiliary burners for preheating the
baghouse should be added.
Unstable combustion during startup can cause some carbon carryover,
which may result in a sticky particulate. This situation creates the
potential for fires in the fabric filter when a combustion source and an
adequate oxygen supply are available. Therefore, during startup, the
fabric filter hoppers that collect the particulate should be emptied
continually. More importantly, unstable combustion conditions during
startup should be minimized by going through proper incinerator startup
procedures.
7.4.7.2 Shutdown. The top priority during shutdown of a fabric
filter is avoiding dewpoint conditions. Bag cleaning and hopper emptying
are lower priority items.
When processes operate on a daily cycle, the last operation of the
day should be to purge moisture and acidic materials from the fabric
filter without passing through the dewpoint. In the case of a hospital
waste incinerator, tha operator should leave the secondary chamber burner
7-16
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on for a few minutes after combustion is completed to remove moisture from
the fabric filter. Ambient air cculd then be drawn through the system to
purge the remaining ccmcustion products.
After shutdown, 5 to 20 minutes of cleaning should be allowed in
pulse-jet systems. This procedure will help prevent blinding of the
bags. Additionally, continuing to operate the hopper discharge system
while the cleaning system is in operation will minimize the potential of
It is important to note that bypassing the fabric filter during
;irtup, scot blowing, or an emergency may not be acceptable to the
"icabl3 regulatory agency. Such occurrences should be investigated and
addressed during the design stages of development.
-j r- i i ^ o -f r- i ' r~ <\ -«- r-i r\ r I f n
/ . o /-1,-Ao i r. HU.-\ I GU i LcK
Many hospital- incinerator systems utilize a waste heat boiler for
orcducin steam, '//'hen a waste beat boiler is included in the incineration
system, the air
items related to incinerator operation:
1. 3
? I!
The inspector should find cut what sect blowing cycle is used by the
facility and should understand any special provisions in the air regula-
tions related to soot blowing; e.g., does the opacity regulation allow one
6-minute period of increased opacity per hour to accommodate excursions
such as sccc blowing? If possible, tns inspector should observe tne
opacity of emissions during a soot blowing cycle.
Typically, an incinerator/boiler system will "include a bypass stack
(or duct) to allow the incinerator emissions to bypass the boiler when the
boiler is off-line or during an emergency situation (such as loss of power
to the induced draft fan). Cn incineration systems that include a waste
heat boilar but do not include an add-on air pollution control device, the
emissions to the atmosphere are not significantly affected when the bypass
system is used. However, whan both an add-on air pollution control device
and a boiler are part of the incineration system, the combustion gases
typically bypass both the boiler and the air pollution control device when
the bypass stack is used; bypassing the air pollution control device will
7-17
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affect the emissions to the atmosphere. Consequently, the air inspector
should be awara of any special permit conditions (or general provisions of
the regulations) relative to use of the bypass stack (i.e., bypassing the
air pollution control). The inspector should obtain information about the
"acility's operating procedures, frequency of use, and recordkeeping
procedures relative to use of the bypass stack.
7.6 CITIZENS CC;i?LA!NT FOLLGWUP
Air pollution agencies, including EPA, receive many citizens
ccr.;plaints„ Ccr.olaints snould ba welcomed by the Agency since they serve
to increase'ovsral1 surveillance and provide early warnings of developing
problems. Appendix F provides a form wnich can be used to document
citizen complaints.
7.7 REFERENCES FCR CHAPTER 7
1. Hosoital Waste C'tmcustion Study: Cata Gathering Phase. Final Draf
Planninc and Standards, Ressarcn Tri ancle Pay-!<, North Carolina.
EPA 450/3-33-017. Cecemoer 1953. p. 5-2.
_j
2. Ibid.
3. Ibid.
4. U. S. Environmental Protection Agency. EPA Guide for Infectious Waste
Management. Office of Solid Waste. Washington, D.C.
EPA 530-SW-86-014. May 1986.
5. Ecolaire Combustion Products, Inc.- Equipment Operating Manual for
Model No. 43CE.
6. Doucet, L. C. Controlled-Air Incineration: Design, Procurement, and
Operational Considerations. American Hospital Association Technical
Series, Document No. C55372. January 1936.
7. Simonds Incinerators. Operation and Maintenance Manual for
Models 7518, 1121B, and 21513. January 1985.
8. Consumat Systems, Inc. Technical Data Sheet.
9. Ontario Ministry of the Environment. Incinerator Design and Operating
Criteria, Volume II-Biomedical Waste Incinerators. October 1986.
10. Air Pollution Control District of Los Angeles County. Air Pollution
Engineering Manual, AP-40. U. S. Environmental Protection Agency.
May 1973.
7-18
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8.0 GLOSSARY
ABSORPTION.' The process by which gas molecules are transferred to a
1iquid ohase.
j
ACID GASES. Corrosive cases formed during combustion of chlorinated or
halogerated ccmccunas, e.g., hydrogen chloride (HC1).
ACTUAL CUBIC FEET PER MINUTE (acfm)/ A gas flow rate expressed with
respect tc temperature and oressure conditions.
ADIAZATIC SATURATION, " A process in which an air or gas stream is
saturated with watsr vacor without adding or subtracting heat from
the system.
-IR, CRY. ~ir ccntai riing no water vapor.
ASH. The solid debris that is the byproduct of the combustion of solid
""*' ,3 r d v -• ,3 " c
-TC,'1IIATICN. ~ "he reduction cf liquid to i fine spray.
BAROMETRIC SEAL." A column of liquid used to hydraui ical i y seal a
scrubber, or any ccmoonent thereof, 'rcrn the atmosohere or any other
3URN RATE.' The total quantity of *aste tiiat is burned per unit of time
that is usually expressed in pounds of waste per hour.
CHARGE RATE.* Quantity of waste material loaded into an incinerator over
a unit of time but which is not necessarily burned. Usually
expressed in pounds of waste per hour.
CCCURRENT OR CONCURRENT." -low cf scrucoing liquid in the same direction
as the gas stream.
COLLECTION EFFICIENCY.' The ratio of the weignt of pollutant collected to
the total weight cf coilutant entering the collector.
COMBUSTION. A thermal process in wnich organic compounds are broken down
into carbon dioxide (C0:) and water (H:0).
CONDENSATION.' The physical process of converting a substance from the
gaseous ohase to the licuid phase via the removal cf heat and/or the
application of pressure.
CROSSFLOW." Flow of scrubbing liquid normal (perpendicular) to the gas
stream.
3-1
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CYCLONE. A device in which the velocity of an inlet gas stream is
transferred into a confined vortex from which inertia! forces tend to
drive particles to the wall.
CAMPER." An ac1 juscaDi e plate installed in a duct to regulate gas flow.
DEHUMIDIFY. " To remove wafer vapor from a gas streaa.
DEMISTER. A mechanical device used to remove encrained water droplets
from a scrucoed gas stream.
CI.iSITY." 7!.= ratio of the mass cf an object to the volume of the
coject.
DIFFUSION (AEROSOL). Random r;oticn of particles caused by repeated
collisions of gas molecules.
DRAFT.' A gas flew resulting frc;n pressure difference; for example,
between an incinerator and the at.mcsDhere, which moves the products
of ccmoust "'en crom tre incinerator to the atmosphere. (1) Natural
draft: the negative reassure cheated by the difference in aensity
'between the noc flue gases and the atmoscrere. (2} Inducea draft:
the negative pressure created by the vacuum action of a fan or blower.-
between tr.e incinerator a;.c cne stack. (3) Forced draft: the
positive pressure createcj by t,:e fan or olcwer, wnictr supp 1 ies the
primary or second iry air..
CRAG FORCE.* Resistance cf motion of an object through a medium.
9
DUST." Solid particles less than 100 micrometers created by the breakdown
of larger particles.
CUST LOADING." The .-/eight of solid carticulate suspended in an airstreaii
(gas). Usually soressec in terms of grains per cubic foot, grams
per cubic meter, or ccunds oar thousand pounds of gas.
ENDOTHERMIC." A chemical reaction that aoscros heat from its
surroundings. For example: C+H;0+heat --> CO-f-H?
ENTRAINMENT.' 'he suspension of solids, liquid droplets, or mist in a gas
stream.
EXCESS AIR INCINERATION." Controlled burning at greater than
stoichiometric air recuirements.
EXOTHERMIC/ A chemical reaction that liberates neat to its
surrouncings. Combustion is an exothermic reaction. For example:
, --> C0,+heat
3-2
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FEEDBACK CONTROL." An automatic control system in which information about
the controlled parameter is fed back and used for control of another
parameter.
FIXED CAR3CN. The nonvolatile organic portion of waste.
GRID." A stationary support or retainer for a bed of packing in a packed
bed scruboer.
HEADER." A pi-9 used to sucply and distribute liquid to downstream
11." , he energy released ever a unit of time during
ccmb'jstien. Circulated as the heatin^ value (6tu/pcund)xbLirn rate
(pc'jr.^/hcur). Usually oppressed as Bcu/hcur (Btu/h).
HEATING VALUE. The amount of heat that is released when a material is
T >•- ,- -^ i 1 1 *- ^ u 1 1 -T ~i/-ji^\/ ^n T p^
u 'J o v ' u i_ ^- / . u i . I J (J ' u _/ in a M VA
u U L 1 1
^ v p 7* ri _> '^ T j ^ r ' i " "* "^ *, ' T' -i '- ^ i r ' ! i /; " " ~T] 3 ^ t e r " h a c adsorbs T, o i s '" J r e
INCINEPATOP,. * A thermal device wnicn co^ousts organic ccr;;pojnc;s using
heat and oxygen.
INDUCED D.V.FT FAN.' A fan used to ~ove a gas stream by creating a
negative pressure.
INERTIA.'" Tendency cf a particle co rerriain ":n a fixed direction,
r,iooilicy across strea.Ti 1 i-es .
LIQUID-TO-GAS RATIO.' The ratio of the iicuid (in gallons oer minute) to
the inlet gas flow rate (in acfm).
LIQUOR.' A solution of dissolved substance sn a liquid (as opposed to a
slurry, in which the materials are insoluble).
MAKEUP i/ATER. ' >/ater added to compensate for water losses resulting from
evaporation and water disposal.
i
MIST ELIMINATOR." Equipment that removes entrained water droplets
downstream from a scrubber.
3-3
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MOISTURE. Water contained in the wasta which must be evaporated by the
heat generated during combustion.
OPACITY. Measure of the fraction of light attenuated by suspended
"art i cu1 at 2.
PACKED-BED SCRUS3ER."" Equipment using small plastic or ceramic pieces,
with high surface area to volume ratios for intimate gas/liquid
contact for mass transfer.
PA.-TICLE. Small discrete mass cf solid or liquid matter.
RETICLE SIZE. AH expression for t.ne size of liquid or solid particle
usually expressed in microns.
PARTICIPATE EMISSION." Fins solid matter suspended in combustion gases
carried to tha atmosphere. The emission rate is usually expressed as
a concentration such as grains oer dry standard cubic feet (gr/dscf)
corrected to a common base, usually 12 percent C0:.
F-RTIC'JLA.TE MATTER. AS rented no conr.ro 1 technology, any material
except uncciYiDined water that exists as a solid or liquid in the
atmosohere or in a gas stream as r^sasured by a standard (reference)
method at scecified conditions. '*.:* standard method of measurement
and the specified conditions snculd be irnoiied in or included with
PATHOGENIC. Wasta material capable of causing disease.
PATHOLOGICAL. Waste material relating to the study of the essential
nature of disease and generally altered or caused by disease.
PENETRATION. Fraction cf suspended ^articulate that passes through a
col 1ection device.
pH.' A measure of acidity-alkalinity of a solution; determined by
calculating the negative logarithm of the nydrcgen ion concentration.
PRESSURE DROP.' The difference in static pressure between two points due
to energy losses in a gas stream.
PRESSURE, STATIC." The pressure exerted in all directions by a fluid;
measured in a direction normal (perpendicular) to the direction of
PRESSURE, lOTAL." I he algebraic sum of the velocity pressure and the
static pressure.
PRESSURE, VELOCITY." The kinetic pressure in the direction of gas flow.
3-4
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PROXIMATE ANALYSIS. ine determination of the amounts of volatile matter,
fixed carbon, moisture, and nonccmDustibla (ash) matter in any given
waste material.
PYROLYSIS. Tha chemical dastruction of organic materials in the presence
of heat and the absence of oxygen.
QUENCH." Cooling of hot cases by rapid evaporation of water.
RE.:GCNT.~ The material used to react with the gaseous pollutants.
RETE'TICN ~~.'"I,~ •"-;:cunt of time the combustion gases are exposed to
mixing, temperature, and excess air for final ccitDUSticn.
SATURATED GAS/ A mixture of gas and vaoor to \vhich no additional vaccr
cm be added, at specified conditions. Partial pressure of vapor is
ecual to vaoor pressure of the liquid at the gas-vapor mixture
^ -~"cer"; hi-re
' ibuiion of ^articles of different sizes within a
*^ i T^ ^ "* ,'~ "• o i^ p •• c; "^ p r~ "* '" ~* o '
material; present in sufficient quantity to be observable
independently of other solids.
SPECIFIC GRAVITY.' The ratio between the density of a substance at a
Qivsn *"emoara1"ur° and fh? density of ,vatar a*" 4"C.
SPRAY NOZZLE." A device used for the controlled introduction of scrubbing
liquid at prede^ermnod rates, distribution cat terns, pressures, and
u r c Dia t sizes.
STANDARD CU3IC FEET PER MINUTE (scfm).' A gas flow rate expressed ,vith
respect to standard temperature and aressurs conditions.
STARVED AIR INCINERATION. Controlled burning at less than stoichiometric
air requirements.
STOICHICMETRIC. The theoretical amount of air required for complete
ccmoustion of waste to CO, and H20 vapor.
STREAMLINE. The visualized path of a fluid in motion.
3-5
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STUFF AND BURN. A situation in which the cnarging rate is greater than
burning rate to the incinerator.
TEMPER/MURE, ABSOLUTE." Teircerature exoressed in degrees aoove absolute
VAPCR. The gaseous forn of suDstances that are normally in the solid or
liquid state and whose states can be changed either by increasing the
pressure or by decreasing the temperature.
YCLATILI T,*7"""!/. That oorticn cf waste material wnicn can be liberated
tr,c aco i ica11 on or n2a t only.
-. U. S. Environmental Protection Aaency, Control Techniques for
Participate Emissions fro 11 Stationary Sources. Volume I,
tr>A-450/3-31-CG5a. Seote:i!cer 1932.
3-6
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APPENDIX A.
-------
INSPECTION CHECKLIST FOR WASTE CHARACTERIZATION
Date:
Inspectors ra;ne: _
Agency affi1iati on:
Facility n^e:
Facility cc,:r;2CC person: __ Telephone No.
Approximate
percent
Estimating heating value, 31" :/lb:
llasta hard ling practices
1. Are infectious waste proparly bagged and marked, yes/no:
2. Are sharps contained in puncture resistant containers,
yes/re;
3. Are torn or ruptured "red bags1' covicus, yes/no:
4. Are liquids leaking frcn t,se bags, yes/no:
5. Are all reasonable steps being taken to assure integrity of red
bags prior to charging to the incinerator?
Storage practices
1. Storage duration, days:
2. Storage area ternperature, 3F:
Comments:
A-l
-------
ioo
ENDIX 3.
iERATGF
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-------
APPENDIX B. INSPECTION CHECKLIST FOR INCINERATORS
Date:
Inspectors name: __
Agency affiliation:
Facility name:
Address:
Facilicy contact person: Telephone No.
j.i"cineruCcr Cjpe/ ecerati ncj rnoce:
Starved air
Excess air
Batch fed
Is primary air system in good '.,or.(C-"I'irg order, jes/no:
Static pressure in primary cnam^er, in. w.c.:
Primary combustion chamber temDerature, T:
Secondary ccrnoustion chamber temperature, T:
Exit gas oxygen level, 'i,\
Exit gas CO level, '<:
Opacity CEMS inspecced, yes/no, ccri-encs:
Visible emissions from stack, ;<:
Fugitive visible emissions from as in removal:
(Attach Method 9 data form)
Other fugitive emissions observed:
Incinerator shell corrosion and/or hot spots, yes/no:
Audible air leaks, yes/no:
Ash quality:
Visual inspection of waste bed:
Visual inspection of secondary burner:
3-3
-------
Startup procedures:
1. Frequency:
2. Temperature in secondary chamber before charging, 3F:
Shutdown procedures:
1. Temperature in primary chamber at cutoff of secondary burners, °F:
Comments:
B-4
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APPENDIX C.
INSPECTION CHECKLIST FOR POLLUTION CONTROL SYSTEM
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INSPECTION CHECKLIST FOR VENTURI/PACKED-BED SCRUBBERS
Date:
Inspectors name: _
Agency affiliation:
Facility name:
Address:
Facility contact person: Telephone No.
Stack emissions opacity, yes/no (see Method 9 form):
Process fugitives emission, opacity average:
Plume color:
Water vapor plume present (yes/no):
Fan vibration problem (yes/no):
Fan current, amperes:
Scrubber pressure drop, in. w.c.:
M1st eliminator pressure drop, in. w.c.:
Scrubber liquid flow rate, gpm:
Scrubber liquid pressure, psig: .
Scrubber liquid pump current:
Audible pump cavitation (yes/no):
Nozzle pressure, psig:
Physical problems of scrubber (yes/no):
Physical problems of ducting (yes/no):
Scrubber liquid effluent, pH level:
Recirculation tank pH level:
Recirculation tank percent suspended solids:
Mist eliminator feed water .percent suspended solids:
Gas temperature at scrubber inlet, °F:
Gas temperature at scrubber outlet, °F:
Comments:
C-6
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INSPECTION CHECKLIST FOR DRY SCRUBBERS
Date:
Inspectors name:
Agency affiliation:
Facility name:
Address:
Facility contact person: Telephone No.
Process fugitive emissions (yes/no):
Plume color:
Average opacity, percent:
Spray dryer
Approach-to-saturation temperature:
Inlet gas temperature, dry bulb °F:
Outlet gas temperature, dry bulb °F:
•9o-tlet gas temperature, wet bulb °F:
Makeup reagent feed rate:
Recycle reagent feed rate:
Nozzle air pressure, psig:
Nozzle slurry pressure, psig:
Dry scrubber
Reagent feed rate:
SolIds recycle rate:
Comments:
C-7
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INSPECTION CHECKLIST FOR PULSE-JET FABRIC FILTERS
Date:
Inspectors name: _
Agency affiliation:
Facility name:
Address:
Facility contact person: Telephone No.
Stack emissions opacity, 6 min average:
Condensed water vapor plume, presence/absence:
Process fugitive emissions, average opacity:
Plume color:
Pressure drop, baghouse compartment 1, in. w.c.:
Pressure drop, baghouse compartment 2, in. w.c.:
Pressure drop, baghouse compartment 3, in. w.c.:
Pulse cleaning cycle, min:
Pulse cleaning pressure, psi:
Baghouse gas inlet temperature, "F:
Baghouse gas outlet temperature, °F:
Solids discharge rate, Ib/h:
Clean side deposits (yes/no):
Comments:
C-8
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APPENDIX D.
METHOD 9 WORK SHEET
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-------
-MPAMT MAMC
•..5)IBUSS.-«,*».U,, v-
_ t » i
*E£T AOOHESS
•Y
ONE (KEY CONTACT;
STATE ZIP
SOURCE 0 NUM«CR
yg5? EQUIPMENT
t
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13 1 '
1
1
case EMISSIONS
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PI i IMC lAfauvm MH
1
TtQnOVINO CCLOA
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OSPEED
1 EM
ICNTTEMP I
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AiMnMO OMMHM Q
TYWACOETEMMNCO
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WET BULB TEMP , HM. MOOT
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it
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LAYOUT SKETCH
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t Position
Swn
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24
30
OBSERVER'S NAME (PAINT)
OBSERVER'S SIGNATURE
DATE
ORGANIZATION
CgflTlflEO BY
DATE
CONTINUED ON VEO FORM NUMCER
D-l
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APPENDIX E.
SAFETY CHECKLIST
-------
-------
APPENDIX E. SAFETY CHECKLIST
Waste handling
1. Is handling of red bags kept to a minimum? yes/no
2. Is the integrity of red bag waste maintained during handling?
yes/no
Operator protective equipment
1. Does the operator wear proper protective equipment?
a. Hard soled boats;
b. Thick rubber gloves;
c. Safety glasses;
d. Disposable or special coveralls; and
e. Dust mask/respirator
Operating hazards
Are available safety hazards evident?
1. Spilled liquids in the waste handling area
2. Scrubber solution leaks, spills
E-l
-------
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APPENDIX F. CITIZEN COMPLAINT FORM
-------
-------
COMPLAINT FORM'
ormt Of WP»>
Statement o» Mr tf""!Mr«J""ly!i f~i
1C BBC* O"« O«'vi
-tome Address .
i Address
Tel. No.
OfVW tfttf*
Business Address ______________
HI Not* fcntvr Non« i
Business Teleonone No.
Extension
• NAME OF COMPANY OR SOURCE.
II NV
T Nature o» emission comolameo of (Cheek DOXI Smoke j |
Dust C] Soot C3 Odors C3 Otner C
Oescrioe odor or emission
3 One »na time eminions ooscfvea
4 it ooinote. desiqrvate soecific source
5 M«ve vou or »nv memoer o« your nousenoid oecome ill because of these em.mons'
Yes D No C3
6 Oescrioe nature of illness ••——————~~~—~^——
7 State any oama^e done to your orooerty. nome. (urnnure. iutomoo.ie. cloth.ng, etc..
8 Will you testify in court' Yes
| | i" "« a
I declare under oenalty ol oeriury tn«t the »Dov« information is true and correct.
Executed on _ 19 at .
F-l
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APPENDIX G. EXAMPLE INSPECTION REPORT
-------
Facility Name:
Address:
APPENDIX G. EXAMPLE INSPECTION REPORT
General Hospital
I.D. No.:
Facility Contact:
Title:
Phone No.:
Type of Inspection:
Date:
Time:
Inspector's Name:
Agency:
Source Inspected:
516 Memorial Lane
Raleigh, North Carolina
28421
Mr. George Brown
Facility Engineer
(404) 596-2431
Routine annual Level II inspection
June 30, 1990
7:00 - 11:30 a.m. EDST
John Doe
U. S. Environmental Protection Agency
Region IV
Incineration Facility
Background Information
General Hospital operates one Acme Model 200 controlled-air
incinerator rated at 300 Ib per charge of refuse. The unit is controlled
by an Acme Model 300 venturi scrubber. The incinerator is subject to the
State incinerator emission regulation, No. 4305, which limits particulate
emissions to 0.08 gr/dscf at 12 percent C02 and visible emissions to
20 percent opacity. The State operating permit stipulates that secondary
chamber combustion temperatures be maintained at a minimum of 1800°F with
a retention time of 2 seconds. The permit also stipulates that the
venturi scrubber be operated at a pressure drop of 20 in. w.c. with a
liquid-to-gas ratio of 8 gallons per 1,000 actual cubic feet of exhaust
gas. The incinerator is operated in a batch mode. On a typical day,
operation of the incinerator starts around 7 a.m. with cleanout of ash
from the previous day. The unit is then charged with a mixture of general
hospital refuse and red bag waste and sealed. The incinerator secondary
G-l
-------
chamber is then preheated for approximately 30 minutes with auxiliary fuel
firing. The waste charge is burned for a set time period of 5 hours and
allowed to cool down overnight for ash removal the following morning.
During the initial phases of the waste combustion, the waste material
provides the necessary heat, and the combustion is self-sustaining.
During the later phases of burnout, auxiliary fuel burners are used to
maintain the necessary temperatures.
General Inspection Information
On June 20, 1990, I phoned Mr. George Brown, Facility Engineer, and
notified him that a representative of the North Carolina Air Pollution
Control Division (APCD) and I would be conducting an annual inspection of
the incineration facility on June 30, 1990. Because of the batch mode of
operation of the incinerator, notification of the facility was necessary
to obtain the operating schedule to ensure that the important phases of
operation, Including ash cleanout, charging, and burndown, could be
observed.
On June 30, 1990, Mr. John Smith of the APCD and I arrived at the >
facility at 7 a.m. and met with Mr. Brown. Both Mr. Smith and I presented
our credentials and explained the purpose of the inspection. Mr. Brown
stated that the incinerator was used to burn both general refuse and red
bag wastes. He estimated that red bag wastes comprised approximately 40
percent of the waste burned. Mr. Brown was unable to provide an estimate
of the percentage of PVC plastics in the waste.
Facility Inspection
At approximately 7:45 a.m., Mr. Brown, Mr. Smith, and I moved to the
incinerator location. The incinerator is located on a concrete pad
approximately 75 feet from the loading dock. General refuse contained in
white.plastic garbage bags was stored in two plastic bins on the loading
dock. A third plastic bin contained red bag wastes. The waste on the
dock represented the waste generated by the hospital the previous day for
incineration. The red bag wastes were approximately 30 to 40 percent by
volume of the total wastes to be incinerated. The control panel for the
incinerator contained maximum and minimum temperature thermostat settings
for both the primary and secondary chambers of the incinerator.
Temperature gauges for both chambers were also available on the control
G-2
-------
panel. The exhaust duct from the incinerator passed through an adjustable
throat venturi scrubber followed by a cyclonic mist eliminator. The
venturi scrubber was equipped with a differential pressure meter and
liquid flow meter. An induced-draft fan was located downstream of the
mist eliminator. The fan was equipped with a static pressure gauge. The
exhaust gases were emitted through a 25-foot-tall steel stack.
Inspection Findings
I visually inspected each of the red bags on the loading dock. All
of the red bags were sealed with plastic ties. There were no tears or
punctures in the bags. No sharps were protruding through the bags, and no
liquids were leaking from the bags. Because of safety considerations, I
did not open any of the red bags to characterize their contents. The bags
were stored for one day on the dock at ambient temperatures (90°F max. on
June 30, 1990). I did not observe any garbage or refuse either on the
loading dock or on the concrete incinerator pad. I also did not detect
any noticeable odors associated with the waste. Attachment 1 presents an
inspection checklist for the waste characterization. j
At 8:00 a.m., the incinerator operator opened the charging door to
the incinerator and moved a large steel tray and several empty open drums
to the door of the unit. He then scraped the bottom ash into the tray
with a large hoe and shoveled the remaining ash into the drums. He
immediately wetted down the ash with a nearby water hose. I observed a
slight amount of visible fugitive dust emissions during removal of the ash
prior to wetting. The tray and drums contained fine gray ash intermixed
with a small amount of glass bottles and metal cans and utensils. I did
not observe any non-combusted combustible material. The operator dumped
the wet bottom ash in a nearby dumpster for subsequent disposal at the
county landfill. While the doors were open, I looked inside the
incinerator (I did not enter the unit). There were no obvious missing
chunks in the refractory. Openings to the primary chamber air supply
system did not appear to be plugged.
At approximately 8:30 a.m., the operator rolled the plastic bins
containing the wastes to the incinerator. He manually tossed the red bag
waste and the bags containing the general refuse onto the incinerator
hearth and closed the charging door. At 8:55 a.m., the operator ignited
G-3
-------
the secondary chamber auxiliary natural gas-fired burner to preheat the
secondary chamber. I observed that the control settings for the secondary
chamber were set for a minimum temperature of 1800"F and a maximum of
1975°F. While the secondary chamber was heating up, the operator started
the draft fan and turned on the water flow to the venturi scrubber. At
9:18 a.m., the operator ignited the primary chamber burners. I noted that
the temperature gauge for the secondary chamber indicated a value of
1825°F. I observed that the control settings for the primary chamber were
at a minimum temperature of 1300°F and a maximum of 1500°F. At 9:43 a.m.,
I noted that the primary chamber auxiliary burner had shut off. The
temperature readout indicated a primary chamber temperature of 1425°F.
While the incinerator was operating, I slowly circled the entire unit. I
did not observe any hot spots on the incinerator casing. Attachment 2
presents an inspection checklist for the incinerator.
After inspecting the incinerator, I visually inspected the ductwork
of the exhaust system. I did not observe excessive corrosion- or
noticeable holes. I also did not locate any audible air leaks. I ^
observed a pressure drop of 22 in.w.c. on the venturi scrubber pressure
gauge and a liquid flow rate of 45 gallons per minute. The draft fdn
seemed to be operating properly. I did not observe any excessive
vibrations. The magnehelic indicated a static pressure at the fan of
25 in. w.c. Attachment 3 presents an inspection checklist for the venturi
scrubber.
At 10:30 a.m., I assumed a position 75 feet northeast of the stack
and took visible emission readings for 15 minutes. The stack had an
attached steam plume that dissipated approximately 40 feet from the
stack. Average opacity for the period was 6.5 percent. Attachment 4
presents the visible emission observation form for the period.
Summary of Findings
1. Waste handling procedures complied with EPA recommended
procedures. Infectious wastes were bagged in red plastic bags. I
observed no tears, ruptures, punctures, or leaking liquids from the
bags. Storage time for the wastes was a maximum of 24 hours. I observed
no litter, vermin, or obnoxious odors.
G-4
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2. The State operating permit requires a minimum secondary chamber
temperature of 1800°F. During my observations, the secondary chamber
temperature fluctuated between 1810° and 1875°F.
3. The State operating permit requires a minimum gas retention time
in the secondary chamber of 2 seconds. During the State's initial
compliance test (May 1988), the gas retention time was 2.2 seconds while
burning a 243-lb charge of general refuse and red bag wastes. During the
test, the average secondary combustion chamber temperature was 1845°F and
the fan static pressure was 26 in. w.c. During this inspection, I
estimated a charge weight of approximately 250 Ib. The observed fan
static pressure was 25 in. w.c. and the average secondary chamber
temperature was 1830°F. Although I was unable to actually measure the
flue gas volume, and as a result calculate the gas retention time, the
observed secondary chamber temperature and fan static pressure indicate
that the gas retention time in the secondary chamber should be similar to
the measured rate during the initial performance test.
4. The State operating permit requires a minimum venturi scrubber
pressure drop of 20 in. w.c. I observed a pressure drop of 20 in. w.c. as
indicated by the scrubber magnehelic.
5. The State operating permit requires a minimum liquid-to-gas ratio
of 8 gallons per thousand actual cubic feet of flue gas. During the
State's initial compliance test, the liquid-to-gas ratio was
8.2 gal/1,000 acf with a liquid flow rate to the venturi scrubber of
48 gal/min. During this inspection, I observed a liquid flow rate of
50 gal/min. Although I was unable to actually measure the flue gas
volume, and as a result the liquid-to-gas ratio, the observed liquid flow
rate indicates that the liquid-to-gas ratio should be similiar to the
measured rate during the initial performance test.
6. State regulations require that average opacity as measured by EPA
Method 9 not exceed 20 percent. I observed an average opacity of
6.5 percent for 15 minutes during the inspection. Opacity did not exceed
20 percent for any 6-minute period.
7. I did not observe any documentable violations of applicable rules
and regulations during this inspection.
G-5
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INSPECTION CHECKLIST FOR INCINERATORS
Date:
Inspectors name:
Agency affiliation: &f># - Ae*>'oN
Facility name: i
Address: 5/£ Memorial Aa^& Rale'.ak N.C..
Facility contact person: George. Arcxw Telephone
Incinerator type/operating mode:
Starved air ^_
Excess air
Batch fed \/L
Intermittent duty
Continuous duty
Charging rate, Ib/h: 300 /fes
No. of charges/h: -3.
Is primary air system in good working order, yes/no: ye.s
Is secondary air system, in good working order, yes/no: yes
Static pressure in primary chamber, in. w.c.: .
Primary combustion chamber temperature, °F:
Secondary combustion chamber temperature, °F: /?
Exit gas oxygen level, £:
Exit gas CO level, %:
Opacity CEMS inspected, yes/no, comments:
Visible emissions from stack, %:
Fugitive visible emissions from ash removal: i/WY s /.'«»/ f emi^f^s fioe*i-3s.
(Attach Method 9 data form) ' w
Other fugitive emissions observed:
Incinerator shell corrosion and/or hot spots, yes/no: A/O
Audible air leaks, yes/no:
Ash quality: PI'N&. gray qsA - A/0 ohr/'ot*s t/*/knrtv&0/ COrtbusJ-i'U«s
Visual inspection of waste bed: /V7fl
Visual inspection of secondary burner: A//A
-------
Startup procedures:
1. Frequency: 1- per
2. Temperature in secondary chamber before charging, °F:
Shutdown procedures:
1. Temperature in primary chamber at cutoff of secondary burners, °F:
Comments: ~7^g /uC''
-------
INSPECTION CHECKLIST FOR VENTURI/PACKED-BED SCRUBBERS
Date:
Inspectors name: _ 'John Doe.
Agency affiliation: £PA - Ke.<*!
Facility name:
Address: S/t, /ffgAW/o/ La*,* /?a/g/g
Facility contact person: £ gorge Rt-o^u Telephone
Stack emissions opacity, yes/no (see Method 9 fonn):
Process fugitives emission, opacity average: _ VOA/C.
Plume color: Gr<*
Water vapor plume present (yes/no):
Fan vibration problem (yes/no):
Fan current, amperes: /v//Q — Sfgf/e. pressure. AS/*.
Scrubber pressure drop, in. w.c.:
Mist eliminator pressure drop, in. w.c.: A///?
Scrubber liquid flow rate, gpm: H-s
Scrubber liquid pressure, psig:
Scrubber liquid pump current:
Audible pump cavitation (yes/no):
Nozzle pressure, psig:
Physical problems of scrubber (yes/no): /V0
Physical problems of ducting (yes/no): A/o
Scrubber liquid effluent, pH level:
Recirculatlon tank pH level:
Recirculatlon tank percent suspended solids:
M1st eliminator feed water percent suspended solids:
Gas temperature at scrubber inlet, °F: A///)
Gas temperature at scrubber outlet, °F: /V//9
Comments : TAf hysical arafar-et/vte. &£ ^4e £cr«loker
/A/
-------
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OBSERVER'S NAME (PRINT)
Jo n N DOC.
OBSERVER'S SIGNATURE DATE
^^U. A^i_ 6/30/70
ORGANIZATION
CERTIFIED BY DATE
LV. S £ 9f\ 'i/l£/ciC>
CONTINUED ON VEO FORM NUMBER
-------
TECHNICAL REPORT DATA
'Please 'tsa Instructions On me reverse oeiore comaer.nri
' f&£-i4i?/ 1 PO fifil !2' 3. RECIPIENT'S ACCESSION NO.
4.
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15
TITLE ANOSUSTITLE
Hospital U'aste Incinerator Fiel
Evaluation ,'ianual
AUTHOR(S)
Stacy Smith, Steven Schliesser,
Stephen Edgerton
d Inspection and Source
Hark Turner,
PERFORMING ORGANIZATION NAME AND ADDRESS
Midwest Research Institute
Suite 350
401 Harrison Oaks Boulevard
Gary, North Carolina 27513
. SPONSORING AGENCY NAME ANO ADDRESS
U..S. Environmental Protection
Stationary Source Compliance Di
Office of Air Quality Planning
Washington, D.C. 20460
SUPPLEMENTARY. NOTES ,_ ..
£?A nork Assignment Manager
James Topsale, Region III, Phil
oa.n Sflundpr*. ^TD. Washington,
Agency
vision
and Standards
5. REPORT OATF.
February 1989
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT
10. PROGRAM ELEMENT NO.
11. CONTRACT GRANT NO.
68-02-4463
13. TYPE OF REPORT AND PERIOD COVEF
14. SPONSORING AGENCY CODE
*
adelphia, Pennsylvania
O.C.
6 ABSTRAC
This manual summarizes the information necessary for conducting field ,
inspections of hospital waste incinerators. The manual is intended for use by
Federal, State, and local field inspectors.
The document presents the following information: (a) basic inspection
procedures, (b) descriptions of the types' of hospital waste incinerators,
(c) descriptions of air pollution control systems which might be used on hospital
incinerators, and (d) inspection techniques for hospital incinerators. Inspectio
checklists also are provided.
on
17 '
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