oBWV
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
EPA-600/7-80-002
January 1980
Control Assay
Development:
Methodology and
Laboratory Verification
Interagency
Energy/Environment
R&D Program Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research ano} Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic/
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
systems; and integrated assessments of a wide'range of energy-related environ-
mental issues.
EPA REVIEW NOTICE
This report has been reviewed by the participating Federal Agencies, and approved
for publication. Approval does not signify that the contents necessarily reflect
the views and policies of the Government, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/7-80-002
January 1980
Control Assay Development:
Methodology and Laboratory Verification
by
W.F. Longaker, S.M. Hossain, and A.B. Cherry
Catalytic, Inc.
1500 Market Street
Philadelphia, Pennsylvania 19102
Contract No. 68-02-2167
Task No. 9 and 12
Program Element No. EHE623A
EPA Project Officer: Robert A. McAllister
Industrial Environmental Research Laboratory
Office of Environmental Engineering and Technology
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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ACKNOWLEDGEMENTS
The following personnel of Catalytic, Inc. made major contributions
to the technical work performed under this directive:
A. B. Cherry J. W. Mitchell
S. M. Hossain J. C. Watt
W. F. Longaker
Special acknowledgement is made to R. P. Hangebrauck, initiator of
the concept of Control Assay Development as an approach for gathering basic
environmental data, and also to T. K. Janes, W. J. Rhodes and C. A. Vogel of
the U. S. Environmental Protection Agency for their continuing advice, counsel
and guidance throughout the project.
ii
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CONTENTS
ACKNOWLEDGEMENTS
ABSTRACT
FIGURES
TABLES
SECTION 1
1.1
1.2
1.3
SECTION 2
2.1
2.1.
2.1.
2.2
2.2.
2.2.
2.2.
2.2.
2.3
2.4
2.4.
2.4.
2.4.
2.4.
2.4.
SECTION 3
3.1
3.1.
3.1.
3.1.
3.1.
3.2
3.2.
3.2.
3.2.
3.2.
3.2.
3.2.
CONTROL ASSAY DEVELOPMENT
Introduction
Application .....
Implementation
WASTEWATER METHODOLOGY
Background
Sampling Procedures
Sample Analysis
Pretreatment
General Comments
Phenol Removal
Hydrogen Sulfide and Ammonia Removal
Cyanide Removal
Preparation of Composite Sample
Screening Procedures
Solids Removal ,
Carbon Adsorption ,
Biological Oxidation
Ion Exchange
Chemical Oxidation ,
GASEOUS EMISSION METHODOLOGY
Background
Module Description
Applicability
Sampling
Analysis
Preliminary Measurements
Introduction
Apparatus
Reagents
Stack Geometry, Temperature and Gas Velocity
Measurements
Moisture Content ,
Gas Composition
1
1
2
3
5
5
15
15
17
17
18
19
22
23
25
25
27
36
43
46
48
48
49
51
52
54
55
55
56
56
56
56
57
til
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CONTENTS (Continued)
3.3 Screening Procedures with Carbon
3.3.1 Introduction
3.3.2 Summary of Method
3.3.3 Apparatus
3.3.4 Reagents
3.3.5 Preparation
3.3.6 Sampling Procedures
3.3.7 Sample Handling Procedures
3.4 Gas Screening Procedures with Scrubbing Module ...
3.4.1 Introduction
3.4.2 Summary of Method
3.4.3 Apparatus
3.4.4 Reagents
3.4.5 Preparation
3.4.6 Sampling Procedure
3.4.7 Sample Handling Procedures
3.5 Gas Screening Procedures with Scrubbing and Carbon
Adsorption Modules
3.5.1 Introduction
3.5.2 Summary of Method
3.5.3 Apparatus
3.5.4 Reagents \
3.5.5 Preparation
3.5.6 Sampling Procedures
3.5.7 Sample Handling Procedures
SECTION 4 SOLIDS METHODOLOGY
4.1 Background
4.2 Screening Procedures
4.2.1 Applicability
4.2.2 Current Testing
4.2.3 Supplemental Testing
SECTION 5 LABORATORY VERIFICATION
SECTION 6 WASTEWATER SCREENING
6.1 Synthetic Wastewater Composition
6.2 Solids Separation
6.2.1 Initial Concepts
6.2.2 Selected Alternative
6.2.3 Test Work
6.2.4 Discussion of Results
6.3 Carbon Adsorption
6.3.1 Initial Concepts
6.3.2 Selected Alternative
6.3.3 Test Work
6.2.4 Discussion of Results
58
58
59
59
59
59
63
64
65
65
65
66
66
66
69
70
71
71
71
71
71
71
73
74
75
75
77
77
77
78
79
82
82
85
85
86
86
86
87
87
89
89
91
lv
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CONTENTS (Continued)
6.4 Biological Oxidation 92
6.4.1 Initial Concepts 92
6.4.2 Selected Alternative 93
6.4.3 Test Work 93
6.4.3.1 Batch Testing 97
6.4.3.2 Continuous Units 99
6.4.3.3 Control Assay Batch Test 99
6.4.4 Discussion of Results 108
6.5 Ion Exchange Ill
6.5.1 Initial Concepts Ill
6.5.2 Selected Alternative Ill
6.5.3 Test Work Ill
6.5.4 Discussion of Results 112
SECTION 7 CONCLUSIONS AND RECOMMENDATIONS - WASTEWATER 114
SECTION 8 GASEOUS EMISSIONS SCREENING
8.1 Gas Blend Composition 11*7
8«2 Modified Sampling System Evaluation 11*7
8.2.1 Initial Concepts 117
8.2.2 Selected Alternative 120
8.2.3 Test Work 120
8.2.4 Discussion of Results 124
SECTION 9 CONCLUSIONS AND RECOMMENDATIONS - GASEOUS EMISSIONS 130
REFERENCES 131
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FIGURES
Number
1. Wastewater test sequence 6
2. Phenol extraction apparatus 20
3. Typical adsorption isotherm 32
4. Carbon column apparatus 34
5. Gaseous emission screening sequence 47
6. Gaseous emission screening train alternatives 53
7. Grab sampling bulb 60
8. Carbon screening train 61
9. Grab sampling bulb with dual stopcock arrangement .... 62
10. Detail of scrubber 67
11. Scrubber screening train 68
12. Combination scrubbing and carbon adsorption screening
train 72
13. Initial wastewater test sequence 80
14. Carbon isotherm plot 90
15. COD and BOD addition by dry bacteria 98
16. Continuous biological reactor results 107
17. Results for synthetic waste sample 115
18. Scrubber evaluation apparatus 118
19. Gaseous emission test sequence 119
20. Combination scrubbing and carbon adsorption screening
train 121
vi
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TABLES
Number Page
1. Coal Gasification Wastewater Sources and Characteristics... 8
2. Coal Liquefaction Plant Wastewater Sources and
Characteristics 9
3. Treatment Technologies Available for Specified Pollutants.. 10
4. Data Sheet for Composite Sample 24
5. Activated Sludge Seed Acclimation Schedule 40
6. Organic Composition of Synthetic Waste 83
7. Inorganic Components of Synthetic Waste 84
8. Activated Carbon Test Results 88
9A. Air Stripping/Oxidation Tests 95
9B. Effect of Volume on Air Stripping/Oxidation 95
10. Dry Bacteria - COD and BOD Data 96
11. Biological Oxidation - Batch Reactor Results 100
12. Continuous Biosystem Treatability Data - Unit A 101
13. Continuous Biosystem Treatability Data - Unit B 104
14. Results of Ion Exchange Testing 113
15. Screening Train Pressure Drop Testing 123
16. Run #1 - Scrubber Evaluation 125
17. Run #2 - Scrubber Evaluation 126
18. Run #1 - Carbon Adsorption 127
19. Run #1 - Scrubbing Followed by Carbon Adsorption 128
vii
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SECTION 1
CONTROL ASSAY DEVELOPMENT
1.1 INTRODUCTION
Control Assay Development (CAD) is a program designed to provide
information for preliminary evaluation of the effectiveness of selected control
techniques for removing pollutants from multimedia discharges. CAD is a
significant and important aspect of the EPAls data acquisition program for
environmental assessment of fuel conversion/utilization systems.
All coal conversion and associated products/byproducts upgrading
processes generate gaseous, liquid and solid wastes. Some of the more impor-
tant control needs include H^S, COS, mercaptans, SO,,, NO , hydrocarbons and
£m £ X
particulate removal from gaseous emissions; removal of phenol, ammonia, sulfide,
organics, heavy metals and cyanides from aqueous waste streams; and prevention
of solid waste leachate problems. When such pollutants are removed from waste
streams and converted to useable products, downstream waste treatment problems
and environmental impacts are automatically improved.
More data are needed on the detailed characteristics of the various
products, byproducts and waste streams generated by coal conversion systems.
Limited upgrading tests have been conducted with coal conversion products and
byproducts. More tests are necessary to characterize effluent streams, product/
byproduct quality and determine catalyst life. Results from these tests and
sampling and analysis campaigns will undoubtedly show the need for additional
control technology development and are, therefore, an important part of the
overall environmental management program.
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1.2 APPLICATION
Relatively little operating data on control technology for laboratory,
pilot or commercial-scale coal conversion systems exist in the literature.
Data acquisition by actual field testing should be given high priority.
Laboratory scale tests that can be performed in the field for control technology
assessment of treatment operations/processes are discussed in this report.
The CAD approach will be quite useful under circumstances where
control technology has not been defined, or where environmentally satisfactory
interim methods are being used which may not represent best technology/economic
practice on a commercial scale. Pilot plants and development units for new
coal conversion technologies are examples of these situations. In such cases,
CAD byproduct removal operations may be employed usually on a temporary basis
to remove pollutants which would not normally be discharged from a full-scale
commercial facility, thereby rendering the test waste samples more typical of
the discharges that will eventually be generated.
In conceiving CAD methodologies, a basic assumption is made that the
program would operate in conjunction with an IERL Level 1 sampling and analysis
(S/A) effort. The CAD team will be responsible for producing treated samples
which will be turned over to the IERL Level 1 S/A team for analyses. CAD
procedures also include special field analyses that aid in the selection of
appropriate control assay operations. Any analyses which are required for
proper operation of a CAD treatment process such as pH, oxygen uptake rate,
etc., will be performed by members of the CAD field team. Level 1 chemical
and bioassay procedures will be used to provide test data for evaluating the
effectiveness of the treatment schemes employed.
For every raw sample processed under CAD procedures, a number of
treated effluent samples will be produced. Therefore, judgement should be
applied in selecting raw samples. If it is known from previous experience
that some of the effluents may not be harmful, or that their treatment schemes
and ultimate fate are well established, then they should not be included in
the CAD program. For example, raw water treatment system effluents are well
characterized and their disposal options well known. Therefore, these would
not normally be included in the CAD schedules, even though they might be
included in the Level 1 S/A effort.
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1.3 IMPLEMENTATION
Before the actual CAD effort is initiated, data needs must be estab-
lished and used to help identify test requirements as well as any anticipated
problems. These requirements are similar to those identified under the IERL
Level IS/A Schemes.
1. Process data such as temperature and pressure must be known.
2. A pre-test site survey must be made to verify process data and
tentative sample points selected.
3. Pre-test site preparation must be specified to have sample
points accessible and outfitted with appropriate nozzles,
valves, etc. Electrical, water and other services must be
provided, where needed.
Detailed process data are necessary for the CAD effort for the
following reasons:
1. From a knowledge of the process and the composition of the
input materials and products, preliminary estimates about
pollutants likely to be found in waste streams are made. This
analysis will be helpful in the planning of control assay
operations.
2. Prior knowledge of the waste stream flow rates, their pressures
and temperatures must be known for selection of proper sampling
methodology and also for preparing composite waste samples from
various individual streams.
3. Familiarization with the process and the plant will ensure
knowledge of where to look for waste streams.
The raw samples and the treated effluent samples will be analyzed by
the Level 1 S/A protocols. Some of these analyses will be performed in the
field and some in the home laboratory. In certain instances, additional tests
are recommended to aid CAD evaluations.
A phased approach is recommended for data gathering. The first
phase, CAD-1, will utilize control assay operations selected from classical
and more common treatment operations/processes. CAD-1 concepts and procedures,
the subject matter of this report, are essentially screening studies designed
to gather basic, broad-based indicative information where little or none
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currently exist. The second phase effort (with the benefit of CAD-1 and Level
1 sampling and analysis results) will concentrate on those streams previously
found by CAD-1 to be exceeding the effluent decision criteria limitations.
These problem streams will be re-examined using additional control assay
operations more specifically designed to remove particular problem pollutants.
The procedure to gather raw samples, for the CAD Phase 1 and 2 efforts
will be essentially the same as for Level 1 and Level 2 S/A techniques.
However, sample sources and quantities needed for CAD will differ from those
specified by S/A procedures.
CAD wastewater screening tests include the following pretreatment
operations: solvent extraction of phenol, ammonia and hydrogen sulfide
stripping, and chemical oxidation for cyanides. Pretreated wastewater will
then be processed through the following operations: filtration, bio-oxidation,
activated carbon adsorption and ion exchange.
CAD procedures for gaseous emissions will include unit operations
for the removal of particulates and gases/vapors. Particulate will be removed
through a cyclone/filter assembly. Gases and vapors will be removed through
the following operations: gas cooling (indirect water cooling); alkaline
scrubbing; and activated carbon adsorption.
The principal control approaches for solids (e.g., resource recovery,
incineration and fixation) are not easily conducted in the field. Incineration
equipment becomes impractical to outfit and operate in a CAD mobile facility.
Chemical fixation or encapsulation techniques commercially are proprietary and
samples would have to be forwarded to a selected process vendor if data are to
be developed. These approaches are not reasonable until a Level 1 environmental
assessment data gathering campaign is completed and these data show the need
for treatment of the particular solid wastes. Detailed characteristics of the
solid wastes and their leaching properties are not available for coal conversion
systems. This information would normally be collected during the Level 1
environmental assessment. Some additional testing is suggested in the report
to supplement the existing S/A procedures.
CAD investigators will require a fairly thorough familiarity with the
SASS train operating manual, with IERL S/A procedures manuals, and with
selected analytical procedures contained in Standard Methods .
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SECTION 2
WASTEWATER METHODOLOGY
2.1 BACKGROUND
The Control Assay Development (CAD) program for wastewaters is
intended to provide an initial evaluation of selected treatment processes and
their applicability to coal conversion aqueous process wastes. CAD testing
equipment and procedures have been designed for mobility and ease of operation
in the field, to enable technicians to perform screening operations at a plant
site and provide samples for analysis by IERL Level 1 analysis procedures.
Figure 1 shows the test sequence which will be performed on a
composite sample taken at the plant. A 400-liter composite sample is required
to provide sufficient quantity for all screening tests and analyses. Process
streams which are to make up the composite sample are first analyzed for
phenol, ammonia, cyanide and sulfide content and treated to remove these
contaminants prior to compositing. The purpose of byproduct removal (when
required) is to render the sample more representative of a commercial-size
plant wastewater, where pollutants present in high concentrations will have
typically been recovered as marketable byproducts. Floating oil and scum will
also be removed from the sample at this point.
The recommended screening procedures are not intended to provide
scale-up design data for a treatment plant, but rather, will indicate the
potential applicability of a particular treatment process and provide in-
formation to be used as a basis for further studies. The tests have been
limited to those treatment technologies which in actual practice (a) have
proved the most successful, (b) are most universally applied, and (c) can be
accomodated in a CAD mobile test facility.
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SOURCE A
SOURCE B
BY - PRODUCT
REMOVAL
1
T
FOR LEVEL I
ASSAY
COMPOSITE
SOLIDS
REMOVAL
AIR STRIPPING/
OXIDATION
i
CARBON
ADSORPTION
2
3
BIO
-OXIDATION
1
CARBON
ADSORPTION
4
5
6
ION EXCHANGE
^» i-_im «*• — —^ «— ^^^ •»
CHEMICAL
OXIDATION
Figure 1. Wastewater test sequence.
6
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Various types of wastewater generated in coal gasification and
liquefaction processes are:
1. Process Wastewater,
2, Coal Pile Runoff,
3, Process Area Storm Water Runoff,
4. Cooling Tower Slowdown,
5. Boiler Slowdown, and
6. Water Treatment Slowdown.
Of these, process wastewater has the most pollutants and, therefore, requires
the most serious attention. Tables 1 and 2 illustrate the different sources
and characteristics of process and other wastewaters from coal gasification
(low to medium Btu) and liquefaction processes, respectively. The process
wastes contain various pollutants including: suspended particles, phenols,
tars, ammonia, cyanide, thiocyanates, sulfides, oils, light hydrocarbons,
chlorides, other dissolved organics and inorganics. The pollutant concen-
trations could be very high, resulting in high Biochemical Oxygen Demand (BOD)
and Chemical Oxygen Demand (COD). In addition, the process wastewater will
contain heavy metals originating in the feed coal.
Process area runoff is a fugitive emission and, therefore, requires
collection and equalization. It is expected to contain most of the pollutants
present in process wastewater, and for this reason, is frequently treated
together with process wastewater.
Coal pile runoff characteristics are dependent on the type of coal
used in the plant. This wastewater will contain dissolved organics leached
from coal and coal fines.
Cooling tower blowdown contains dissolved solids, suspended solids,
corrosion inhibitors and bacteriacides. Through leaks in heat exchangers,
cooling tower water can become contaminated with process liquors.
The recommended control assay screening operations are potentially
capable of removing dissolved organics (both biodegradable organics and
biorefractory organics), suspended solids, phenol, cyanide, ammonia, sulfide
and other pollutants listed above to acceptable levels.
Numerous treatment processes are available for the control of pollu-
tants, several affecting more than one pollutant. Table 3 lists various
wastewater treatment technologies and the pollutants affected by them.
7
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TABLE 1. COAL GASIFICATION PLANT WASTEWATER SOURCES
AND CHARACTERISTICS
Process Module
Source
Contaminant
Coal Pretreatment
and Storage
Gaslfier
Particulate Removal;
Gas Quenching and
Cooling; Acid Gas
Removal
Cooling Tower
Utility System
Organics Separation
Wastewater Treatment
Coal-pile runoff;
coal crushing and
cleaning waste
Ash quench/sluice
water
Process condensate;
unrecoverable solvent
Slowdown
Slowdown
Process condensate
Sludges
Suspended Solids;
dissolved organics
Suspended solids; dissolved
inorganics
Suspended solids; non-
emulsified oils; dissolved
organics and inorganics;
spent solvent
Suspended solids; dissolved
organics and inorganics
(volatiles and salts)
Dissolved inorganics;
suspended solids
Suspended solids; dissolved
organics and inorganics
Semisolids
8
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TABLE 2. COAL LIQUEFACTION PLANT WASTEWATER SOURCES AND CHARACTERISTICS
vo
Module
Coal Preparation
Hydrogenation
Pyrolysis and
Hydrocarbon!zation
Hydrotreating
Synthesis Gas
Generation
Catalytic
Synthesis
Phase Separation
Fractionation
Gas Cleaning
Hydrogen
Generation
Supercritical
Gas Extraction
Auxiliary Systems
and Utilities
Source Description
Coal storage piles,
crushing and grinding
operations
Cooling and quenching
operation
Cooling and quenching Foul water from quench
Wastewater Stream
Storm water runoff
Foul water from quench
Condensing overhead
vapors
Cooling and quenching
operation
Shifting Operation
Condensing overhead
vapors
Two or three stage
pressure reduction
Cooling overhead
vapors
Absorption and Purge Flows
regeneration operations
Condensate
Foul water from quench
Condensed unreacted water
Condensate
Condensate from overhead
condenser
Condensate
Cooling and quenching
operation
Shifting Operation
Char quenching
operation
Cooling towers and
boiler
Plant yard area
Foul water from quench
Condensed unreacted water
Foul water from quench
Slowdown
Storm water runoff
Constituents
Suspended particles, dissolved
solids
Phenols, tars, ammonia, thiocyanates,
sulfides and chlorides
Phenols, tars, ammonia, thiocyanates,
sulfides and chlorides
Phenols, ammonia, sulfides
Phenols, tars, ammonia, thiocyanates,
sulfides and chlorides
Phenols, tars, ammonia, thiocyanates,
sulfides and chlorides
Phenols, ammonia, sulfides
Oils, light hydrocarbons, phenols
ammonia, dissolved sulfides
Light hydrocarbons, dissolved salts
Dissolved sulfides in gas removal
solvent
Phenols, tars, ammonia, thiocyanates,
sulfides, and chlorides
Phenols, tars, ammonia, thiocyanates,
sulfides and chlorides
Phenols, tars, ammonia, thiocyanates,
sulfides and chlorides
Dissolved solids
Suspended particles, dissolved solids,
traces of phenols, oils and tars
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TABLE 3
TREATMENT TECHNOLOGIES AVAILABLE FOR SPECIFIED POLLUTANTS
POLLUTANT
A. Dissolved Organics
1. Undifferentiated
AVAILABLE TREATMENT PROCESSES
Bloconversion:
Fixed Growth
Trickling Filtration
Rotating Biological Contactor
Dispersed Growth
Activated Sludge
High Rate
Conventional
Extended Aeration
Contact Stabilization
Aerated Lagoon
Aerobic (completely mixed)
Facultative
Anaerobic Lagoon
Adsorption, Activated Carbon
Granular
Powdered
Liquid-Liquid Extraction
Irrigation
Thermal Combusion
Distillation
Stripping (air or steam)
Membrane Separation
Ultrafiltration
Chemical Oxidation or Reduction
Freezing
2. Oil
Bioconversion
Adsorption, Activated Carbon
3. Phenol
Oxidation (by ozonation or chlorination)
Bioconversion
Adsorption, Activated Carbon
Extraction
10
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TABLE 3. (Continued)
Suspended Solids
Separation -
Sedimentation
Filtration
Granular Bed
Pre-coat
Microscreening
Membrane Separation
Ultrafiltration
Flotation
Pre-Treatment -
Coagulation
Flocculation
Dissolved Solids
(Primarily inorganic, plus TSS)
1. General (heavy metals,
salts, some organics,
others)
Precipitation
Ion Exchange
Electrolysis
Metal Replacement
Freeze Crystallization
Reverse Osmosis
Evaporation
Electrodialysis
2. Heavy Metals
Precipitation
Ion Exchange
3. Cyanide
Alkaline Chlorination
Ozonation
11
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TABLE 3. (Continued)
4. Nutrients
a. Nitrogen
Bioconversion, Aerobic (Uptake of TKN)
Bioconversion, Anaerobic (denitrification)
Ion Exchange
Stripping (of ammonia, by air or steam)
Breakpoint Chlorination (of ammonia)
b. Phosphorus
Bioconversion, Aerobic
Ion Exchange
Precipitation
pH/Alkalinity/Acidity
Neutralization with acid or alkali
E. Floating Substances
1. Solids
2. Oils
3. Foam
Surface Skimming
Surface Skimming
Oil Emulsions
Emulsion-breaking (by steam, acid, alum,or
iron salts, or commercial emulsion breakers)
G. Coarse Solids
Screening
Sedimentation
H. Bacteria
Chlorination
Ozonation
Irradiation
I. Color
Chemical Oxidation or Reduction
Bioconversion
Activated Carbon
12
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The pretreatment and basic unit operations to be used under CAD test
work and the pollutants affected by them are:
Pretreatment Unit Operations Pollutants Affected
1. Extraction Phenol
2. Stripping NH3, H2S,
3. Chemical Reaction Cfor Cyanides and Sulfides
Specified Pollutants)
Basic Unit Operations
4. Filtration Suspended and dissolved solids,
and suspended/emulsified oil
5. Biological Oxidation Dissolved organics
6. Activated Carbon Adsorption Dissolved organics
7. Ion Exchange Dissolved solids, heavy metals
Gravity oil separation is not included above because standard CAD
procedures will permit raw samples to sit in their containers for sufficient
time for oils and oily scum to float. Only subnatant wastewater will be used
for test purposes.
Two basic treatment methods exist for the removal of dissolved
organics, both having considerable versatility; biological conversion, and
carbon adsorption.
Biological treatment in conjunction with various physical/chemical
methods, is the most widely practiced treatment method for wastes containing
dissolved organics. It will continue to play a key role in industrial waste
treatment for the foreseeable future. Activated carbon adsorption is expected
to be employed with increasing frequency for removal of bioresistant dissolved
organics.
Both biological treatment and activated carbon adsorption have
fundamental limitations. Some organic materials are non-biodegradable (or may
degrade very slowly) and certain types are toxic to the biological organisms.
Similarly, some organic materials, particularly low molecular weight compounds,
are not easily adsorbed on carbon. Fortunately, there frequently is considerable
overlap in the applicability of biological treatment and carbon adsorption.
Many refractory compounds can be adsorbed, and many non-adsorbable compounds
are biodegradable. There are, of course, exceptions where either or both of
these processes will not be effective.
13
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The range of available technology is much broader for the removal or
control of other pollutants such as suspended solids, oil, heavy metals,
cyanide, and phenol. It includes numerous chemical and physical processes
such as: clarification, filtration, chemical coagulation and filtration,
precipitation, ion exchange, ozonation, stripping, neutralization, dissolved
air flotation, and oil separation by gravity. Frequently, one or more of
these processes must be employed as a specialized pretreatment method on
segregated process wastestreams to render the stream compatible for combined
treatment by downstream processes. Cyanide removal (by alkaline chlorination),
dephenolization (by solvent extraction or adsorption), and ammonia stripping
are examples of pretreatment applications.
Since detailed waste characteristics of the samples may. not be
known, the unit operations selected are inherently designed to affect as mp.ny
types of pollutants as possible. To test the effectiveness of these unit
operations, effluent samples from them have to be analyzed by Level 1 Sampling/
Analysis (S/A) protocols. This could create a large number of samples for
analysis, if no limit is placed on the number of unit operations and raw
samples. To place a reasonable boundary on the amount of test work required,
the following procedural logic has been followed:
1. Although a large number of treatment processes/operations were
initially considered, only a relatively few, broad based,
generic-type technologies are included in the CAD test sequence
(Figure 1).
2, Three of these unit operations are used for pretreatment of the
different raw samples, if these pretreatments are found to be
necessary by simplified field analysis. The remaining unit
operations are used to test a composite wastewater prepared by
mixing pretreated and/or raw samples. Compositing of waste-
waters is quite typical in real-life waste treatment situations.
3. To concentrate investigative efforts on important problem
areas, the composite for CAD screening procedures is limited to
process wastewaters only (e.g., no cooling tower blowdown),
unless substantial over-riding circumstances are present.
It is assumed that the CAD field team members will have a technical
background in the environmental field, have a basic knowledge of chemical
14
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principles and be quite familiar with standard laboratory procedures. The CAD
field crew is required to perform a number of analyses on-site when preliminary
results are required to establish subsequent operating parameters.
2.1.1 Sampling Procedures
IERL Level 1 sampling procedures and standard practices will be used
as a guide by the CAD team. These are discussed in "IERL-RTP Procedures
Manual: Level 1 Environmental Assessment," Chapter V (2). It is recognized
that CAD procedures may require modifications to the IERL methods in order to
facilitate the larger sample size. For example, a stream which would normally
be sampled with a dipper to obtain 10 liters may require a pump to obtain 400
liters. Stainless steel drums become the sample containers, rather than glass
or plastic bottles. When modifications to Level 1 procedures are necessary,
general recommendations regarding materials of construction and equipment
cleaning have been suggested.
Procedures for handling the final 10-liter sample from each screening
operation will be in accordance with the IERL manual.
Flow measurement of each stream which will be included in a composite
sample is particularly important. Preparation of the composite sample is
described in Section 2.3.
2.1.2 Sample Analysis
A 10-liter sample will be removed from each of the screening opera-
tions indicated in Figure 1. This volume is required by Level 1 analytical
procedures for water organic and inorganic analyses. An additional 15 liters
will be required for modified bioassay testing of the composite sample and the
final effluent sample.
For purposes of defining field analytical responsibility, it is
assumed that the CAD team will be working independently, but concurrently with
a Level 1 S/A assessment team at the site. The Level 1 team will support the
handling, preparation and analytical requirements for samples generated by the
CAD team. On the surface, this approach is felt to offer the most cost
effectiveness and will avoid the duplication of mobile laboratory facilities
required for selected testing that must be conducted on site. (Future exper-
ience, however, may dictate otherwise, since the operating schedules/timetables
of both the CAD and S/A teams may preclude their being on site for the same
15
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simultaneous period. In that event, the CAP laboratory facility's capability
will have to be enlarged to the extent necessary for field handling of samples
in accordance with IERL Level 1 S/A procedures.
The approach suggested above does not preclude the CAD team from
performing limited analyses for the purpose of characterizing waste streams
to guide in the selection of optimum operating parameters for CAD treatment
unit operations. The supplemental analytical tests employed in CAD are
relatively simple and inexpensive, and are described in the applicable methodology
sections.
16
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2.2 PRETREATMENT
2.2.1 General Comments
Wastewater streams encountered during CAD testing are expected to
contain phenolic compounds, ammonia, sulfides and cyanide. These materials
should be present in large enough quantities to make their recovery economical
in a full scale plant; however, pilot plant operations may not be able to
afford the capital investment for recovery equipment. Since it is expected
that CAD testing procedures will, at least initially, be employed using
wastewater streams produced by pilot plants, it becomes necessary to pretreat
these samples in order to simulate the characteristics of the waste effluent
that would be expected from a full-scale plant.
The analytical effort expected of the field team members is not
extensive for any of the CAD testing. However, some analyses must be performed
to evaluate the need for pretreatment and the degree of surrogate pollutant
removal after a sample is processed through a pretreatment step.
The individual streams used to make up the composite sample will be
analyzed using inexpensive test kits and a decision will be made by the CAD
team leader as to which streams will be subjected to byproduct removal treat-
ment before compositing. Because of the variation in flow rates and composition
of the waste streams expected in different plants, it is not possible in this
Section to specify exact equipment sizes or times required for byproduct
removal. Each plant will present a new set of circumstances which must be
evaluated before the screening procedures are commenced. A suggested maximum
concentration for each species is listed in the individual write-ups in this
Section. After byproduct removal and compositing, the sample should be
analyzed to determine the effectiveness of any pretreatment steps employed,
and also to insure that the composite sample meets the acceptable limits for
the components in question.
Three of the four byproduct removal procedures are highly pH dependent:
cyanide, ammonia, and hydrogen sulfide. When a waste sample is encountered
which requires removal of more than one of these byproducts, a representative
aliquot is tested as a side study to determine if it is possible to perform
all the procedures in a single container by beginning with a higher pH and
adjusting towards the final goal for the composite sample of about pH 7.0.
If not, then the byproduct removal steps will have to be performed individually.
17
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2.2.2 Phenol Removal
2.2.2.1 Introduction—
Liquid-liquid extraction removes phenol from a wastewater by con-
tacting the stream with an organic solvent. The solvent should have a high
affinity for removing phenol from water, be mutually immiscible with the
water, have a significant difference in density from the water, have a reason-
ably low viscosity, and be low in cost. In most commercial applications,
employing various methods of countercurrent contacting, approximately 99
percent of the phenol can be removed from a waste stream.
Solvents which have been used for phenol removal include benzene
(or light oil), isopropyl ether, tricresyl phosphate, and other proprietary
commercial solvents. Isopropyl ether is suggested for CAD work.
For all subsequent discussions regarding specific CAD testing, a
basic presumption is made (and hereby emphasized) that the investigators will
be cognizant of, and will employ, proper safety precautions and equipment
when handling the samples and while performing the tests.
Several extractor types are capable of performing the required
intimate contacting and subsequent separation. The Podbielniak centrifugal
countercurrent extractor, which combines the advantages of a sieve column and
a centrifuge, is suggested for CAD work. This compact unit has been applied
previously to the dephenolization of waste streams; and removal efficiency is
in the range of 95% or better, depending on the affinity of the solvent for
phenol.
The Podbielniak extractor is constructed with a series of concentric
"bands" perforated with many holes. When the machine is rotated (up to
several thousand r.p.m.), the heavy liquid is thrown outward by centrifugal
force, while the light liquid is displaced inward. This action causes a
series of countercurrent "contacts" as the fluids pass through the holes,
thereby producing multiple-stage extraction.
2.2.2.2 Summary of Method—
A wastewater sample is pumped into the extractor at a rate of 1 gpm
or less. Simultaneously, the solvent is pumped into the other extractor
inlet at a variable flowrate of up to 1 gpm. The locations of the inlets for
the respective liquids are determined by their relative densities (the heavier
fluid enters the center of the extractor, the lighter fluid enters the outside
ring of the extractor).
18
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Phenol removal will vary with the change in solvent-to-water ratios,
which can be varied by manually opening or closing the valves in each line.
2.2.2.3 Apparatus—
Liquid-liquid extraction unit (Podbielniak or equivalent)
Phenol test kit (Hach or equivalent)
pH meter
Pumps(2) variable speed to 1 gpm
Sample containers
Series of volumetric flasks (1000,500,250,100,50,10 ml)*
Assorted pipets*
2.2.2.4 Reagents—
Isopropyl ether
2.2.2.5 Preparation—
Analyze the individual stream samples collected for preparation of
the composite sample for phenol using the colorimetric test kit. Make dilutions,
as required, for samples with high phenol concentrations. Streams containing
concentrations which will produce a level of greater than 250 mg/1 of phenolic
compounds in the composite sample will be subjected to the extraction process.
2.2.2.6 Procedure—
Set up the apparatus as shown in Figure 2. Mix all sample streams
requiring treatment in a suitable container. Start the flow of sample and
solvent to the extraction unit. The sample flow should be approximately 1
gpm and solvent flow 0.5 gpm. Continue operation until all of the sample has
been processed by the extractor. Analyze the effluent from the reactor for
phenol, again using the colorimetric test kit. Repeat the extraction procedure,
if necessary, until phenol concentration has been reduced to the specified
level.
2.2.3 Hydrogen Sulfide and Ammonia Removal
2.2.3.1 Introduction—
Hydrogen sulfide and ammonia can be removed from wastewater by
differential batch distillation. This process involves sparging air or steam
into a drum containing the wastewater until the concentration of the hydrogen
sulfide and ammonia has reached a predetermined level.
*This laboratory glassware will be required for all analytical determinations
and is not repeated in subsequent sections.
19
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WASTEWATER
to
o
DE PHENOL! ZED
WASTEWATER
SPENT
SOLVENT
Figure 2. Phenol extraction apparatus.
-------
The pH of the system has an effect on the ease of removal of hydrogen
sulfide and ammonia. If the pH of the waste-water charge is adjusted to about
7, hydrogen sulfide will be liberated easily by the sparged air. Ammonia
stripping is optimal when the pH of the wastewater charge is raised to about
11 (accomplished by addition of sodium hydroxide).
A high percent removal rate of hydrogen sulfide can be accomplished
in a matter of minutes. Theoretically, with perfect mixing, a 98 percent
ammonia removal efficiency from a 55-gallon wastewater charge at 20 C using
60 cubic feet per minute of sparged air will be accomplished in about 13
hours. If the wastewater temperature is increased to about 60 C, the time
requirements will drop to less than 3 hours. Therefore, with the addition of
a heat source and a proper air diffuser device, a high percent removal of
ammonia will take place in a reasonable amount of time.
2.2.3.2 Summary of Method—
Air is compressed and pumped to the bottom of a drum which contains
the composite wastewater sample. The air is discharged through a sparger
mechanism which diffuses the air bubbles through the liquid, allowing intimate
contact and mass transfer from the liquid to the air. A submersible heater
is used to heat the sample to approximately 60 C during the sparging operation.
2.2.3.3 Apparatus—
Sample containers
Immersible heater
Air compressor (capacity 60 cfm) and tubing
Air diffusion mechanism
Hydrogen sulfide test kit
Ammonia test kit
Thermometer (0°-100°C)
2.2.3.4 Reagents—
NaOH - 50% solution
H2S04- 10 Normal
2.2.3.5 Preparation—
Analyze the sample for ammonia and hydrogen sulfide. The acceptable
limit in the composite sample for ammonia is 500 mg/1. Position the immersible
heater in the sample container and bring the sample temperature to 60°C.
Adjust the pH of the solution to 11 or greater.
21
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2.2.3.6 Procedure—
After the sample has reached 60 C begin aeration. Analyze the
sample every hour until an acceptable ammonia level has been reached. At
this point, the pH is adjusted to 7.0 and aeration is continued until the
sulfide has been removed to a constant concentration level.
(Note: If cyanide is also to be removed from this sample, perform this
operation before lowering the pH. See Section 2.2.4.
2.2.4 Cyanide Removal
2.2.4.1 Introduction—
Complete destruction of the cyanide ion can be accomplished with
chlorine gas in an alkaline solution (pH 10 or greater) at room temperature.
During the chlorination step, heavy metals that accompany cyanide can precipi-
tate as hydroxides and ferro or ferricyanides. The iron compounds react very
slowly with chlorine, and for this reason, vigorous agitation is required in
the process.
Addition of sodium or calcium hypochlorite will also completely
destroy cyanide without the need for the addition of caustic. Vigorous
agitation, however, is also required with this method.
2.2.4.2 Summary of Method
Sodium hypochlorite is added to the sample and vigorously agitated
to destroy cyanide.
2.2.4.3 Apparatus—
Sample container
Air compressor and diffusion mechanism or laboratory mixer to
provide agitation.
2.2.4.4 Reagents—
Sodium hypochlorite
2.2.4.5 Procedure—
Place the sample to be treated in an appropriate size container
and begin agitation. Add sodium hypochlorite and agitate until the cyanide
level reaches 1 mg/1 or below, (If this level cannot be achieved with hypo-
chlorite alone, adjust the sample to pH 10 with caustic and continue treatment
until the specified cyanide concentration is reached.)
22
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2.3 PREPARATION OF COMPOSITE SAMPLE
Demonstration and commercial size synfuel plants will normally
contain a central wastewater treatment facility wherein many process waste
streams are combined, mixed and equalized prior to entering the various
treatment steps. A Level 1 S/A assessment would be concerned primarily with
the treated effluent stream being discharged. In these cases, CAD may not be
required unless data have been obtained that indicate unsatisfactory perfor-
mance of the plant.
Where process wastes are not being treated in a central facility,
the individual streams must be composited to simulate the combined feed to a
treatment plant. This situation might be encountered in pilot plants.
Knowledge of the process and/or similar conversion processes is essential to
enable the CAD team to select individual waste streams that will most likely
eventually be combined for subsequent treatment.
A data sheet for recording information needed to prepare a composite
sample is attached as Table 4. The composite will be a mixture of each
stream in proportion to its flow. Following is an example of this calculation:
Assuming a 400-liter sample requirement,
Stream No. Flow Rate Proportional Volume Calc.
1 100 gpm
2 90 gpm
3 150 gpm
4 30 gpm
37Q gpm 400 L
The composite sample should be used in the next CAD step (Solids
Removal) as soon as possible. Streams requiring pretreatment should be
handled first, and added to freshly obtained samples from other sources that
do not require preliminary handling.
Two 55-gallon stainless steel drums, equipped with agitators, will
normally be adequate to composite the sample quantity required for subsequent
pre-screening and screening operations. The drums must be fitted with tight
covers to prevent contamination from airborne dust, etc.
23
100
370
90
370
150
370
30
370
X
X
X
X
400
400
400
400
L =
L =
L »
L *
108
97
162
33
L
L
L
L
-------
TABLE 4. DATA SHEET FOR COMPOSITE SAMPLE
Composite sample volume required:
Date/time prepared:
Stream Date/time Flow Type Date/time Final Final Proportional Volume
—No. Source Sampled Rate Pretreatment Pretreated Temp. PH Calculations
10
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2.4 SCREENING PROCEDURES
2.4.1 Solids Removal
2.4.1.1 Introduction—
Some type of solids removal is usually required in industrial
wastewater treatment applications. The three basic types of solids separation
commonly employed are gravity separation, physical straining, and filtration
through granular media. These processes are often combined with chemical
coagulation and flocculation in order to produce higher solids removal effic-
iencies. Solids removal can be utilized as a polishing step to meet effluent
requirements. It is also used as a pretreatment step to assist subsequent
unit processes by reducing the solids loading they must handle. This latter
approach will be taken in the CAD methodology. The composite sample will be
filtered without benefit of chemical treatment in order to avoid unnecessary
altering of the sample's characteristics.
2.4.1.2 Summary of Method—
Solids are removed from the composite wastewater sample by a
combination of sedimentation and pressure filtration through a cartridge
filter. The effluent from the filter is collected and will be used in subse-
quent CAD testing procedures.
2.4.1.3 Apparatus—
Centrifugal pump with stainless steel or teflon coated liquid
contacting surfaces (Capacity: 5 gpm)
Cartridge filter holder - stainless steel or polypropylene with
replacement cartridges (75-micron Serfilco cartridges or equivalent)
Flexible teflon tubing 1/2-inch I.D. and pump fittings
Sample containers to hold a 400-liter composite sample (stainless
steel or polypropylene)
2.4.1.4 Reagen ts—
None required.
2.4.1.5 Preparation—
The sample should remain quiescent in the storage container for at
least one hour to allow settling of larger particles. Floating oil and scum
should be removed from the sample at this time.
25
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2.4.1.6 Procedure—
Attach the filter cartridge to the pump and begin the sample flow
through the filter. Adjust the flow rate to approximately 1 gpm. If the
filter becomes clogged during the run, stop the feed pump and replace the
cartridge according to the manufacturerls instructions. Collect the effluent
in the sample container and reserve for further testing procedures. Submit a
10-liter sample for Level 1 analyses.
26
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2.4.2 Carbon Adsorption
2.4.2.1 Introduction—
Activated carbons are made from a variety of materials including
wood, bituminous coal, sawdust and petroleum residues. The activation process
develops a complex pore structure on the surface of the carbon granules. It
is this porous structure which encourages adsorption - the phenomenon by
which molecules adhere to a surface with which they come in contact. Usually
removal of organics by activated carbon is the result of van der Waal's
forces - a physical attraction between molecules.
Activated carbon preferentially adsorbs high-molecular weight
organics and/or non-polar substances from aqueous solutions, and is frequently
used to remove odor, taste and color from water.
When the organic loading is too low to support a biological system,
or when the organic materials in a waste stream are toxic to bacteria, carbon
can be used as an alternative treatment system. Carbon is sometimes used
after biological treatment to serve as a polishing step to achieve greater
organic removal.
Activated carbon may be used in a batch or column operation; however,
the most efficient application is in continuous-flow, packed-bed columns. In
packed beds, the carbon remains stationary while the wastewater is introduced
either from the top or bottom of the column. The column itself is a vertical,
cylindrical pressure vessel. It is of sufficient height that the required
depth of carbon represents only 50 to 60% of the total internal height. This
allows for bed expansion during backwash operations. The column is provided
with an internal screen support which holds the carbon bed above the bottom
of the vessel.
A common variation of the packed-bed design is the fluidized bed.
In this type of column, the wastewater is introduced at the bottom of the
column at a flow rate high enough to slightly expand the carbon bed. This
design is useful when moderately sized solids are present in the wastewater.
Another variation of the packed-bed design is the moving or pulsed
bed adsorber. In columns of this type, the wastewater is fed to the column
from the bottom and flows upward through the carbon bed. A storage vessel
located on top of the column holds fresh or reactivated carbon. This fresh
27
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carbon is fed to the top of the column at intervals based on the contaminant
loading and the adsorptive capacity of the carbon. As carbon is added at the
top of the column, an equal amount of spent carbon is discharged from the
bottom of the column and sent for regeneration. This design greatly reduces
the complexities of changing the carbon in the column and allows uninterrupted
operation of the column.
All types of columns experience a gradually increasing pressure
drop across the system due to a build-up of particulate matter in the filter.
Because of this gradual plugging of the column, a backwashing step becomes
necessary when an unacceptable pressure drop is experienced. Obviously,
pretreatment of the wastewater to remove suspended particles will allow for a
longer column run between backwashing steps. The suspended solids level in
the water to be treated determines whether a pretreatment step is necessary;
however, for most wastes this step will increase the efficiency of the column
enough to be warranted.
Variables which affect the adsorptive capacity of activated carbon
include; type of carbon, pH of water to be treated, amount of contact time
and temperature during contacting.
Activated carbon will be tested in CAD to determine if it can
remove organic material from a wastewater sample. An isotherm test will
first be performed to determine the approximate loading rate (amount of
carbon required) and the effects of pH on organic removal. Continuous column
operation will be used to process the composite sample.
Carbon adsorption column testing is performed twice in the CAD
procedures. Referring to the flow scheme for wastewater (Figure 1), the
methodology is applied after filtration, and following bio-oxidation. The
column operation procedure is applicable to both cases, however, the isotherm
test is only required for the first sample. The amount of carbon and optimum
pH as indicated by this test is applicable in both cases. The two different
column runs shall be identified as;
Carbon-1: Final treatment (after filtration)
Carbon-2: Intermediate treatment (in series between bio-
oxidation and ion exchange)
28
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2.4.2.2 Summary of Method—
A filtered wastewater sample is contacted for one hour in a standard
shaking apparatus with seven different concentrations of activated carbon.
Determination of TOC removal will indicate the adsorptive capacity of the
carbon and the dose required for maximum organic removal. A second portion
of filtered sample is further tested by contacting eight individual aliquots
for one hour with the selected carbon dosage over the pH range of 4 to 11.
Determination of TOC removal will indicate the optimum pH condition. The
composite sample is then passed through a series of columns to remove dissolved
organic material.
2.4.2.3 Isotherm Apparatus—
250-ml Erlenmeyer flasks with stoppers(16)
Eight place wrist-action shaker
Millipore filter assembly and 0.45-micron filters
1-liter vacuum flasks and vacuum sourceC2)
250-ml vacuum flask
100-ml graduated cylinder
pH meter
Filter paper - Whatman No. 42 or equivalent
Buchner type filter funnels
TOC analyzer
Triple beam balance, sensitivity to 0.1 grams
2.4.2.4 Isotherm Reagents—
H2SO^ - 1 Normal Solution
NaOH - 1 Normal Solution
Powdered activated carbon (ICI Darco 400 or equivalent)
Distilled Water
2.4.2.5 Isotherm Preparation—
Preparation of the activated carbon must be done at the home labora-
tory prior to the start of field testing.
1. Pulverize approximately 50 grams of granular activated carbon
so that 95% will pass through a 325-mesh screen. Oven dry the
pulverized sample for three hours at 105°C.
29
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2. On an analytical balance, weigh the following amounts of
carbon: 0.05, 0.1, 0.5, 1, 2, and 10 grams. Also weigh ten
portions of a 5-gram amount.
3. Place each of the portions in marked containers (glassine
envelopes) which can be sealed for transfer to the field.
2.4.2.6 Procedure—
1. Obtain two liters of composite sample and filter through
Whatman No. 42 (or equivalent) to remove any suspended particu-
late matter.
2. Run TOC on an aliquot of this filtrate.
3. Mark eight Erlenmeyer flasks for identification and empty the
preweighed carbon (0.05, 0.1, 0.5, 1, 2, 5, 10 gm) into the
appropriate flasks. Care must be exercised to be certain that
all the carbon is transferred from the container to the test
flask. Flask No. 8 shall serve as the blank,
4. Measure 100 ml of filtered sample into each of the eight
flasks. Place all flasks on the shaker apparatus and agitate
for 'at least one hour. The flasks may be filtered and placed
on the shaker at three to five minute intervals to allow
sufficient time to filter each sample immediately after the
prescribed contact time has elasped.
NOTE: Large doses of carbon may raise the pH of the solution with
time. After 30 minutes on the shaker, the pH should be
checked and readjusted to the initial value, if necessary.
5. After the contact time has elasped, filter the contents of
each flask into a clean container. The high doses of carbon
may require up to ten minutes of filtration time when filtered
through the millipore system. To minimize filtration time,
the sample may be filtered through a coarse filter (42 Whatman)
before being filtered through the millipore filter.
6. Run TOC tests on all filtrates.
7. Tabulate the data as indicated on the sample data sheet (Figure
3). The residual waste material concentration, C, is obtained
directly from the filtrate analysis. The amount adsorbed on
the carbon, (total mg) is obtained by subtracting the value
30
-------
of C from that of C , the influent concentration, and adjusting
o'
for sample size. Dividing X by M, the weight of carbon used
in the test, gives the amount adsorbed per unit weight of
carbon.
On log-log paper, plot X/M on the vertical axis (ordinate)
against C on the horizontal axis (abscissa) and draw the best
straight line through the points. See example Figure 3.
Extend the adsorption isotherm to the vertical line which
represents the influent waste concentration. Where these two
lines cross, read the X/M value on the ordinate. This will
give the maximum possible loading of waste material expressed
in milligrams/gram, (52 mg waste constituent adsorbed per
gram activated carbon, in the example). It should be remembered
that this loading can only be achieved if the carbon is brought
into equilibrium with the influent waste stream. Calculate
the waste loading to be applied to the columns during screening
by the following formula:
H _ CD CCo)
1000
where W = Total waste load (grams)
1 - Volume of sample through columns (liters)
C - Waste influent concentration (mg/1)
o
, (100 1) (712 mg/1)
1000 mg/gm
W = 71.2 gms
Using the X/M value of 52 mg/gm, calculate the amount of
carbon required to treat the waste.
52 mg/gm - °'°^ ** =5.2% loading
gms = 1369 gms carbon required = 3.0 Ibs.
10. Place the 5-gram portions of carbon into each of eight flasks.
Adjust the pH of eight 100-ml aliquots of the filtered composite
sample to pH 4, 5, 6, 7, 8, 9, 10, 11. Note and record any
changes in the sample - i.e., evolution of gases, formation of
precipitate, etc. Stopper the flasks and place on the shaker
for one hour. Filter and analyze the samples for TOC, and
plot pH vs. final concentration (TOC, mg/1). This graph will
indicate the pH of most efficient carbon adsorption.
31
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ADSORPTION ISOTHERM
Cliant:
Plant and Location:.
Contract No
Tnl Oil*
Sampla No.
Sampli Sourca:
Raw Sampla: pN>
Otter
SS*
.rog/l
jng/l Color*
.units
Known Contaminants:.
Sampli Pratraatmant: .
Tart Paramttar (Adtorbatt):.
Typa Carbon:
Sampli Voluma:
pH:
ml.
Agitation Tima:
mm.
Tamparaturt:
or °F
pH Adjustmint (during tnt):
Gr*m» «f
Carbon
0.0000
Idtorbat.
X
AdtOriMd
/Units:
i/m
Loading
C. Equilibrium Concantration (Units:,
Figure 3. Typical adsorption isotherm
32
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2.3.2.7 Column Apparatus—
Four-foot glass columns, 3-inches in diameter, fitted with
support screens to hold the carbon; end plate fittings are
also required, and pressure gauges may be installed on each
column. (See Figure 4K
Support structure for columns
Pump capable of uniform delivery rates of approximately 40Q
ml/min-gear, diaphragm, centrifugal, piston-type or cam finger
pump.
Container for use as a sample feed reservoir - 40 gal. stainless
steel or polypropylene.
Water Supply - Source of uncontaminated water for backflushing
and charging the columns.
Portable pH meter
Sample collection container - 40-gal, stainless steel or poly-
propylene.
Graduated Cylinder - 5000 ml
Bucket - 2 gallon
2.4.2.8 Column Reagents—
Activated Carbon - granular 8 x 30 standard sieve size.
NaOH - 1-Normal Solution
H-SO, - 1-Normal Solution
2.4.2.9 Column Preparation—
A. Assemble the apparatus as shown in Figure 4.
B. Charging the columns
1. Remove the top flange of the first column for filling and
add approximately three feet of uncontaminated tap water.
Measure the volume of water as it is added.
2. Make a carbon slurry in the 2-gallon bucket and pour
slowly into the top of the column. Repeat this procedure
until carbon has been added to a level of 3.0 feet.
During addition of the slurry, occasional draining of the
33
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PRESSURE GAUGE
(OPTIONAL)
TOP
VENT
VALVE
POSITIVE
DISPLACEMENT
PUMP
50 MESH
SCREEN
T
CARBON COLUMN
(TYP. FOR 4)
T
SIPHON BREAK
EFFLUENT
COLLECTION
VESSEL
Figure 4. Carbon column apparatus.
-------
excess water will be required to prevent overflowing the
column. Measure and record the amount of water added
with the slurry and drained from the columns for use in
calculating the dilution factor.
3. Replace the top flange and repeat the charging procedure
for each successive column.
C. Backwashing the columns
1. Attach the water supply line to the bottom of the first
column.
2. Slowly start the flow up through the column and increase
the rate until the bed has expanded to within three
inches of the top of the column, allowing only the fine
carbon particles to escape. Gently tap the column during
backwashing to remove air pockets.
3. Stop the water flow to the column and adjust the level to
1 inch above the carbon.
4. Repeat the backwash procedure for each column.
2.4.2.10 Column Procedure—
1. With the effluent discharge valve closed and all top vent
valves open, fill each column (except column one) with
tap water to remove any air in the columns. Record the
amount of water required.
2
2. Adjust the pump flow rate to 2 gpm/ft . With a 3-inch
diameter column, this will be about 370 ml/min.
3. Begin feeding waste to the first column. When column 1
is completely filled with liquid, close the top vent and
open the discharge valve and syphon breaker.
4. Begin running the waste through the columns at the constant
rate specified above.
5. Collect the entire volume of effluent.
Measure the amount of sample collected. Record this amount and
calculate and record the amount of dilution water used to charge the columns.
Carbon-1; Final Treatment - submit 10 liters for Level 1
analysis.
Carbon-2: Intermediate Treatment - save the effluent for use
in CAD ion exchange screening.
35
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2.4.3 Biological Oxidation
2.4.3.1 Introduction—
Biological oxidation is a unit process commonly used for removal of
organics from industrial wastewaters. In this process, bacteria and other
living organisms are used to break down organic compounds to simpler forms,
and (in theory) ultimately to carbon dioxide and water. Methods of contacting
the wastewater with the biological solids Csometimes called biomass or biota)
vary according to wastewater flowrate, land area available and the desired
percent removal of organics. Typical installations include trickling filters,
aerated lagoons and activated sludge processes. An aerated lagoon is any
basin in which biological organisms are allowed to grow and proliferate by
aerating with addition of a feed material (dissolved organics in wastewater).
Solids are kept in suspension and, therefore, the effluent solids concentration
is equal to the solids concentration in the lagoon. In the activated sludge
process, solids are allowed to settle in a clarifier and a portion of the
solids is recycled to the aeration system. The excess solids produced by the
system must be disposed of by other means. A trickling filter is a packed
bed of media covered with a biological slime. The wastewater flows through
the media and the organisms in the biomass assimilate and oxidize the organics
in the water. Waste products such as C0«, NH« and partially oxidized organics
are carried off in the effluent. As the biomass grows thicker, those organisms
close to the media surface are deprived of food and oxygen and thus become
anaerobic. At this point, part of the biomass is sloughed off and the growing
process begins again.
In order to obtain meaningful data from a pilot biological reactor,
the microorganisms used in the system must be allowed to become acclimated to
the wastewater for a period of several weeks. To meet this requirement, it
will be necessary to send one member of the CAD field team to the plant site
about one month prior to the actual control assay testing.
Laboratory results using a synthetic coal conversion wastewater
indicate that a large percentage of organics can be removed by aeration
alone. For this reason, two units will be run simultaneously to differentiate
between removal of organics by air stripping/oxidation and by biodegradation.
36
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2.A.3.2 Summary of Method—
The wastewater sample is treated by two systems - one containing
previously acclimated microorganisms and the other having no biologically
active seed. Both systems are aerated for 48 hours before removing a 10-
liter sample for Level 1 analyses.
2.4.3.3 Apparatus—
Stainless steel containers (2) - each having a 55-gal» capacity.
Dissolved oxygen meter and accessories
pH meter and probe
Air compressor with tubing, air diffusion stones, and rotameters
for flow measurement
Laboratory equipment for determination of suspended and volatile
solids. (See Reference 1)
COD apparatus (See Reference 1)
Variable speed pump and tubing (0-5 gpm)»
BOD apparatus (See Reference 1)
TOG Analyzer
2.4.3.4 Reagents—
NaOH - 1 Normal Solution
H-SO, - 1 Normal Solution
Probe solutions for pH and dissolved oxygen meters
Anti-foaming agent
NH^OH - 10% Solution
Na.HPO. - 10% Solution
2 4
Reagents necessary for performing BOD and COD tests
2.4.3.5 Preparation—
During the preliminary plant visit, information concerning the
waste streams which will make up the composite sample will be obtained by the
CAD team leader. To avoid performing byproduct recovery steps on the waste
which will be used only for acclimating the seed, the team leader must make a
judgement, based on process knowledge, as to the procedure for preparing the
37
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acclimation mixture. In certain instances, for example, it may be possible
to reduce byproduct contaminant levels by dilution of the sample rather than
using the prescribed treatment procedures. This would limit the amount of
equipment and effort required for seed acclimation to the point that it would
be feasible for one person to perform this function. Waste treatment facilities
in the vicinity of the plant should also be visited during the preliminary
survey to gain information on types of activated sludges available locally.
2.4.3.6 Seed Acclimation—
Prior to the start of CAD screening, one team member will travel to
the plant for the purpose of acclimating a seed. Duties during the three
weeks will include:
1. Obtaining seed material from a local waste treatment plant;
2. Preparing the feed according to the instructions of the team
leader;
3. Batch addition of feed to the unit using the fill-and-draw
method; and
4. Monitoring the unit to determine approach of steady-state
conditions.
Biological treatment of a waste sample is the most complex unit
process which will be studied under the CAD wastewater program. For this
reason, it is recommended that the field operators be thoroughly familiar
with the techniques of start-up and operation of bench-scale, activated
sludge biological reactors. An illustrative approach is presented below.
Obtain a 100-liter sludge sample from the secondary clarifier
underflow (sludge return) line at a local activated sludge treatment plant
and analyze this sample for suspended solids (SS) and volatile suspended
solids (VSS). Ideally, this sludge would be obtained from a plant which
normally treats coke oven or petroleum wastes; however, this will not always
be possible and the alternative is to obtain sludge from a municipal sewage
treatment plant. Also, a 100-liter sample of the clarified effluent will be
obtained for use as a diluent to make up the initial reactor SS concentration.
The activated sludge sample must be placed under aeration as soon
as possible after collection, and aerated vigorously to maintain a dissolved
oxygen concentration of 2.0 mg/1 or greater. It is also advisable to maintain
aerobic conditions in the clarifier supernatant sample.
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After determining the solids concentration in the return sludge
sample, calculate the amount of sludge required to produce a suspended solids
concentration of 5000 mg/1 in the reactor based on a total volume of 150.
liters. For example, 75 liters of sludge having a concentration of 10,000
mg/1 of solids would produce approximately the required concentration when
mixed with 75 liters of the clarifier supernatant sample. Mark the 150 liter
(unaerated) liquid surface level on the inside of the reactor, so that water
evaporation losses can be made up daily during the acclimation period.
Using the fill-and-draw method, the proper volume of feed is mixed
with the sludge and aerated in an open container. After 24 hours, the aeration
is stopped for one hour to allow settling of the solids, evaporative water
losses (if any) are made up by filling the container to the fill mark with
tap water, and then a supernatant quantity equal to the next day's feed
volume is syphoned off. This process is repeated each day until the reactor
has reached the final feed strength.
The feed strength will be increased each day for a period of fifteen
days, at which time the system will be receiving the full waste load. There
are two methods generally employed for increasing feed strength: logarithmic
progression and arithmetic progression. Table 5 indicates the quantities of
feed material to be added to the system.
Although either method of calculating the feed volume is acceptable,
the logarithmic progression is regarded as being preferable insofar as the
conversion to a new waste is done at a more gentle rate during the early
portion of the acclimation period. Should the reactor performance demonstrate
process stress during acclimation, rest the unit (aerate without feed) for 24
hours before resuming the feed schedule.
During the acclimation period the operator will monitor the performance
of the system using the following analyses*:
Chemical Oxygen Demand (COD) - Daily on the feed and settled
reactor supernatant
Biological Oxygen Demand (BOD) - Several days per week on feed
and settled supernatant
Suspended Solids (SS) - Daily on the feed settled
supernatant and on the aerating
reactor contents (Mixed liquor)
* All analytical methods may be found in Reference 1.
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TABLE 5
ACTIVATED SLUDGE SEED ACCLIMATION SCHEDULE
Logarithmic Progression
Arithmetic Progression
Day
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Percent of
Total Volume
9
10
12
14
17
19
23
27
32
37
44
52
61
73
85
Liters
Added
13
15
18
21
25
29
34
41
48
56
66
78
92
110
128
Percent Of
Total Volume
9
14
19
25
31
36
41
47
53
58
63
69
75
80
85
Liters
Added
13
21
29
38
46
54
62
71
79
87
95
103
112
120
128
NOTE: 1. A "heel" volume of 15 percent is provided in the above calulations
to allow space for the settled activated sludge.
2. At the start of the one-hour settling period (immediately after
aeration has been stopped), the reactor volume should be made up
to the 150-liter mark with tap water to adjust for any evaporative
losses. The amount of water introduced should be recorded in the
operating log book...
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Volatile Suspended Solids (VSS) - Same as for SS
pH - Same as for SS (adjusted when
necessary to maintain pH 6.Q-8.0)
Dissolved Oxygen (D.O.) - Daily on the mixed liquor
Oxygen Uptake Rate (OUR) - Same as for D.O.
To determine nutrient requirements for the system the feed sample
will be analyzed for COD, nitrogen, and phosphorous content. Nutrient nitrogen
and phosphorus should be present in the following ratio; COD/N/P = 200/5/1.
Nutrient deficient feed samples will be supplemented with appropriate additions
of ammonium hydroxide and sodium phosphate. When the first BOD results are
obtained, nutrient addition will be modified, if necessary, to the following:
BOD/N/P = 100/5/1.
After the 15th day of the acclimation period, the reactor should be
ready for the CAD screening procedure for biological oxidation. If the
schedule does not permit screening to be performed on the 16th day, the
reactor should be fed daily at the 15th day feed rate, until the CAD test
composite sample is available.
COD, specified above as the principal monitoring analyses, should
be replaced with a TOG analysis as soon as the CAD mobile test facility (with
its TOC analyzer) is on the site.
2.4.3.7 Procedure—
The test composite sample will at this time have already passed
through both the byproduct removal steps and treatment for solids removal.
The volume required for biological oxidation (BIO) and air stripping/oxidation
(ASO) testing is 300 liters (150 liters for each). The remainder of the
composite sample will be held for the Carbon-1 treatment step (Section 2.4.2).
Perform a TOC analysis on the 300-liter composite and add the
required nutrients as described in Section 2.4.3.6. Check the pH of the
sample and adjust to between 6.0 and 8.0 with H-SO, or NaOH, if necessary.
Stop the air flow to the reactor being used for seed acclimation,
evaporative losses, and allow the solids to settle. Syphon off the supernatant,
measure its TOC, and discard.
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Prepare a second reactor f,or comparison air stripping/oxidation.
The volume of sludge remaining in the biological unit after syphoning should
be measured and an identical volume of water will be added to the ASO unit to
approximate the dilution factor encountered in the BIO unit. Add 150 liters
of sample to each reactor and begin aeration.
Adjust the air flow in the BIO system to provide good solids mixing.
The ASO unit should receive the same amount of air flow as measured by the
rotameters. Aerate both systems for 48 hours. Dissolved oxygen, oxygen
uptake rate and pH should be checked periodically on the BIO unit. The
dissolved oxygen available in the system should be at least 2 mg/1. The pH
of the system should be maintained at between 6 and 8.
At the end of the aeration period, stop the air flow to both units,
adjust for evaporation, and syphon 150 liters from each unit after the solids
in the BIO unit have settled. Submit 10 liters (25 liters if modified bioassy
testing is desired) of each sample for Level 1 analyses. The biologically
treated sample will be used for Carbon-2 screening. (Section 2.4.2)
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2.4.4 Ion Exchange
2.4.4.1 Introduction—
The ion exchange process is used to remove inorganic ions from
water. Standard practice is to first remove turbidity and organics from the
waste stream by other means, then introduce the water into a column filled
with an ion exchange resin* Ions in the waste stream are replaced by ions
provided by the ion exchange media, by means of a substitution reaction.
Different types of resins are available depending on the ion or groups of
ions to be removed. Naturally occurring substances which display ion exchange
properties include greensand (glauconite) and bentonitic clay. The development
of synthetic organic resins has made it possible to produce materials with
varying ion exchange properties, capable of removing a wide range of cationic
and anionic materials. The four basic types of ion exchange media include
strong acid, weak acid, strong base and weak base.
2.4.4.2 Summary of Method—
The wastewater sample is passed through a series of three columns
containing appropriate ion exchange resins for removal of toxic metals.
2.4.4.3 Apparatus—
Three 3-inch I.D. glass columns - 45-inches in length, fitted with a
5Q-mesh support screen and bottom drain valve.
1 - Variable speed pump with teflon tubing
2 - Sample storage and collection vessels - capacity 25 gal. each.
Filtration equipment as described in Section 2.4.1.
2.4.4.4 Reagents—
Deionized water
Strong Acid type ion exchange resin
(Rohm & Haas Amberlite IR-120 plus-Sodium form or equivalent).
Weak Acid type ion exchange resin
(Amberlite DP-1 or equivalent).
Strong Base type ion exchange resin
(Amberlite IRA-4Q2 chloride form or equivalent).
2.4.4.5 Preparation—
Introducing a non-filtered feed to the resins may result in a
build-up of suspended particles at the top of the resin bed causing channeling
of the influent stream or excessive pressure drop. To avoid this possibility,
the composite sample will be filtered according to the procedures described
in Section 2.4.1 before ion exchange screening is begun.
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2.4.4.6 Procedure—
A. Charging the columns,
NOTE: Always fully hydrate the resin according to the
manufacturer's instructions before charging it to a
column, and make sure the column already contains some
water during charging. Never allow a charged column
to become dry, since hydration may cause enough expansion
of the resin to break the glass column.
1. Add a slurry of the strong acid resin to the first column
until a depth of 30 inches is reached. During the addition
of the slurry, occasional draining of the excess water
will be required to prevent overflowing the column.
However, do not allow the liquid to fall below the resin
level. Measure and record the amount of water added with
the slurry and drained from the columns for use in calculating
the dilution factor.
2. Repeat step A with the weak acid resin (column 2 in series)
and the strong base resin (column 3), adding each resin
to a depth of 30 inches.
B. Backwashing the columns
1. Attach the pump line to the bottom of the column.
2. Slowly start the flow of deionized water up through the
column.
3. Increase the flow rate until all air pockets are removed
and all resin particles have achieved mobility. The
proper flow rate should produce a 50% expansion of the
bed. Any extremely small particles may be allowed to
pass out of the column.
4. After ten minutes of backwashing, stop the flow and let
the resin settle by gravity.
5, Drain the excess water to a level of approximately 0.5 inch
above the resin level.
6. Repeat steps 1 through 5 for columns 2 and 3.
D. Adsorption
1. Pump the filtered sample to the first column Cstrong
acid) at a rate of approximately 200 ml/min.
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Adjust the stopcock at the bottom of the column so that a
constant liquid level is maintained above the resin.
Collect the effluent from the first column and begin
feeding to the second column at the same rate. Continue
this process through the third column.
After the sample has passed through all three resin
columns, measure the amount of sample collected and
submit 10 liters of the sample for Level 1 analysis.
Record the amount of deionized water initially added to
the columns for use in calculating the dilution factor.
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2.4.5 Chemical Oxidation
2.A.5.1 Introduction
Phenolic compounds and numerous other organic chemicals can be
destroyed by reaction with an oxidizing agent. The choice of an oxidizing
agent rests primarily on its rate of reaction, selectivity, cost and ease of
handling. Several chemical oxidants which are commonly used include:
1) Ozone and oxygen,
2) Hydrogen peroxide,
3) Potassium permanganate, and
4) Chlorine and chlorine containing compounds.
For thermodynatnically reversible reactions, the oxidation-reduction potentials
can be used as a quantitative measure of "oxidizing power," however, most
reactions involving oxidation of organic chemicals are irreversible, and
therefore, the redox potentials are of little use for predicting expected
behavior.
2.4.5.2 Summary of Method
Hydrogen peroxide will be added to the composite sample to oxidize
any remaining organic components.
2.4.5.3 Apparatus
Container for composite sample,
Stirring apparatus (Lightning mixer or equivalent),
Portable dissolved oxygen meter.
2.4.5.4 Reagents
Hydrogen peroxide - 50%
2.4.5.5 Procedure
Measure the dissolved oxygen concentration in the sample remaining
after ion exchange treatment. Cautiously add 50 ml of 50% hydrogen peroxide
with mixing (toxic gases may evolve from this reaction). Repeat this procedure
until a residual dissolved oxygen reading of at least 5 mg/1 is maintained.
Record the amount of hydrogen peroxide required and submit a 10-liter portion
of the oxidized sample for Level 1 analysis.
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SECTION 3
GASEOUS EMISSION METHODOLOGY
3.1 BACKGROUND
Control technology for screening of gaseous samples to determine
potential treatment methods must include unit operations for the removal of
particulates and gases/vapors of concern. Either class of materials may be
organic or inorganic. The types of control technology for gas treatment
include mechanical collection, electrostatic precipitators, filters, liquid
scrubbers/contactors, condensers, solid sorbents and incineration.
Sampling and testing of gaseous streams for CAD is much more difficult
than the relatively simple procedures specified for liquids. The inability
to bring sufficient feed volume into the CAD mobile test facility (as is
possible with liquid samples) limits the use of a number of unit operations
and/or desirable strategies that can be applied in the gaseous emission
screening methodology. The practicality of performing certain types or large
numbers of CAD tests at the source may be restricted by such factors as
limited working space on a platform, logistical problems servicing a platform,
plant restrictions on use of non-explosion proof equipment, personnel safety,
requirements for specialized equipment, and the analytical load generated by
a broad test plan.
Based upon the above considerations, the CAD methodology for gaseous
emissions was developed to be flexible but more reliant on process information.
This permits the user of CAD to be selective in choosing a screening system
and may allow a more simplified approach to certain streams. The screening
test sequences are presented in Figure 5.
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SOURCE
PARTICULATE
REMOVAL
FOR LEVEL
ASSAY
CONDENSATION
CARBON
ADSORPTION
2
SCRUBBING
CARBON
ADSORPTION
Figure 5. Gaseous emission screening sequence.
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3.1.1 Module Description
The control technologies recommended for gaseous emission screening
methodology are:
1) Particulate removal,
2) Gas cooling (condensation),
3) Liquid scrubbing, and
4) Carbon adsorption.
The equipment for these operations is constructed and assembled as
modules, and several combinations or sequences can be arranged. Details of
the module arrangement (screening trains) are discussed in Sections 3.3, 3.4
and 3.5. Following is a brief description of each module and its function in
CAD:
Particulate Removal—The module is a standard Source Assessment
Sampling System (SASS) train cyclone/filter assembly, contained in a heated
oven. For CAD screening purposes, this module serves only to pre-treat the
gas when particulate is present.
Gas Cooling—Hot gases must be cooled to at least 130 F before
entering an activated carbon module. In commercial practice, gases are often
cooled to permit use of cheaper materials of construction (e.g., plastics) in
downstream ducts and equipment. In addition to cooling as a protective
measure, condensation of volatile material is a valuable control technology.
This module also will be a standard SASS train component, except that the
sorbent cartridge is not used and will be taken out of line.
Scrubbing—Liquid scrubbing, using an aqueous alkaline solution, is
specified as the primary control technology in CAD screening for removal of
pollutants in acid gases. Several media were investigated and sodium carbonate
was selected. Carbon dioxide, a common component in many gaseous streams,
will be absorbed in media such as sodium hydroxide, requiring a large volume
of solution and causing logistical problems. The capacity to remove acidic
components at expected concentrations cannot be handled in the standard SASS
impinger assembly, therefore a small counter-current scrubber must be used.
Carbon Adsorption—Activated carbon is being studied for removal of
trace quantities of organic and inorganic materials. The economics of
regeneration usually preclude carbon being used as the primary technology for
49
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removal of high concentrations of organics. Regeneration will not be studied
in CAD. The module is a column canister sized to contain a sufficient quantity
of activated carbon. Calculations show that the capacity of a standard SASS
sorbent module is not adequate for CAD studies.
3.1.1,1 Unit Operations Not Included—Unit operations considered for the
gaseous emission methodology, but not included in the test sequence are:
electrostatic precipitation, flaring, and incineration. Reasons for their
exclusion are discussed below:
Electrostatic Precipitation—The selection of electrostatic precipi-
tation technology depends heavily on conductivity and resistivity properties
of the gas stream. Instead of testing a prototype electrostatic precipitator
unit as a CAD screening procedure, measurement of these properties is recommended
to supplement existing Level 1 protocols. They include:
1) Particle resistivity,
2) Particle size - average diameter,
3) Specific gravity,
4) Bulk density, and
5) Particle size distribution curve.
Direct Combustion (flare)—Flaring is acceptable control technology
for a number of applications, principally in the petroleum refining and other
industries where upset conditions involving large volumes of flammable gases
can be economically handled. It is not recognized or recommended as best
available control technology by regulatory agencies due primarily to lack of
a sufficient data base. A major disadvantage is the absence of equipment and
practical techniques to sample the products of combustion and monitor performance.
Methods and equipment sizes used in pilot plant test runs are not practical
for CAD and have not yielded data that can be used for scaled-up design or
prediction of performance. The disadvantages of flares are presently too
great for the unit operation to be useful in CAD.
Direct Flame Incineration—Thermal incineration is one of the most
effective means for disposal of hazardous waste gases, and despite high
capital and operating cost, will likely be specified more frequently in the
future for problem pollutants. A proper evaluation of the capability of
incineration would involve study of key parameters such as residence time and
temperature.
50
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The manipulation of a number of variables is beyond the scope of, CAD and,
coupled with the general difficulty of handling large volumes of sample,
screening tests on incineration become impractical and are not recommended.
Incinerator manufacturers, however, have compiled a large data base on the
thermal oxidation of organic materials and there is also a high level of
confidence that any organic material can be destroyed.
3.1.2 Applicability
The CAD gaseous emission screening methodology is applicable to
any point source where a Level 1 environmental assessment might be performed.
This is generally intended to mean those sources that discharge directly to
the atmosphere, and does not normally include process lines, internal recycle
or waste gas lines directed to control devices*
Open vents or stacks that are considered sources of uncontrolled
fugitive emissions are not recommended for CAD, Examples of these sources
include relief systems, pressure let-down or control systems, emergency
vents, leaks, spills, etc. They are normally highly variable in composition,
rate, frequency and duration, and control technology is often difficult or
uneconomical to apply. When the materials are hazardous, it is common to
collect the vapors in an exhaust system and direct the combined flow into a
central control system such as a scrubber. Discharges from control systems
are usually of interest to CAD.
3.1.2.1 Need for Process Review
Vents, stacks and other point sources of air emissions are usually
too numerous in the plant site to permit a CAD assessment of each discharge.
A cost effective program can best be achieved by performing a reasonably
complete engineering review of the available data before finalizing sample
points. Process and engineering flow sheets, process and treatment descrip-
tions and all other information should be studied prior to a preliminary site
visit. During the visit, information gaps may be filled by discussions with
plant personnel and/or inspection of equipment and devices. If it can be
established, for example, that the emission is a vapor and contains no particu-
late matter, the most complex and costly test configuration requiring particu-
late sampling modules can be avoided. Furthermore, if the source is a pure,
51
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single component organic material (such as breathing and filling vapors from
a storage tank) CAD may not be needed at all because emissions can be calculated
and potential control technology selected based on the material properties.
3.1.3 Sampling
IERL Level 1 sampling protocols are employed in CAD gaseous emission
methodology. The sampling apparatus for a Level 1 assessment are the grab
bulb for gaseous samples only, and the equipment package for gaseous streams
containing particulate.
The general principles of IERL sampling apply to CAD, but may be
modified to accommodate a more flexible approach in air methodology. This is
best illustrated in Figure 6 which outlines alternative screening arrangements
and associated sampling requirements. For CAD purposes, the standard SASS
modules are used in the following manner:
1. The particulate removal module (cyclones and filter) is used
only for the baseline sample, which will be collected and
analyzed in strict accordance with Level 1 procedures for
environmental assessment. The CAD screening train uses the
same particulate removal module for preconditioning of the
stream prior to entering control devices.
2. The gas cooling module of the SASS train is used in CAD for
evaluating condensation control technology. Operating this
module according to Level 1 assessment parameters will serve
both as condensation screening technology and the means to
provide a sample for evaluation of the applicability and
effectiveness of condensation.
3. The XAD-2 cartridge and the impinger module in the sampling
system is designed to collect the residual pollutants. A side
benefit is the removal of corrosive material which would cause
damage to the vacuum pump, dry gas meter and other components
downstream.
The complete Level 1 analytical protocols shall be performed on the
gas samples produced. The CAD sample sizes shall meet the requirements of
these protocols which presently are:
52
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In
U)
^-^
1
<
I
F
C
E
:>
-------
1) GC analysis: 3 liters (grab)j
2) Physical/chemical testing and health effects: 30 cubic
meters (passed through SASS train) ..
It is recommended that all personnel performing CAD gaseous emission
screening be familiar with Level 1 S/A protocols, especially SASS train
operation.
3.1.4 Analysis
In order to obtain meaningful results from the tests, it is imperative
that each source to be evaluated be sampled according to the Level 1 IERL
methods in addition to the screening sampling. Ideally, both tests will be
run simultaneously. If this is not possible, process data for each source
must be evaluated to determine the constancy of operation and Judgement must
be used to assess the reliability of comparing data from two non-simultaneous
test runs.
The scope of CAD field work may require certain handling, preparation
and preservation procedures and limited analyses on samples that must be
performed on site for reasons of impracticability of shipment, deterioration
within a short time period, etc. Additionally, specific tests necessary for
CAD characterization data to assist in field decisions would be needed.
Level 1 physical, chemical and bioassay procedures are described in Reference 2.
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3.2 PRELIMINARY MEASUREMENTS
3.2.1 Introduction
Preparing the site so that equipment can be positioned properly is
frequently the most difficult and time consuming part of sampling. All sites
should be inspected prior to sampling to determine the best probe locations,
scaffolding requirements, availability of electrical connections at the
sampling site, restricted areas and safety hazards. Flow rates through the
SASS train and the screening train(s) will be "pseudo-isokinetlc" as prescribed
for Level 1 assessment sampling. Several parameters must be measured before
screening tests can be performed. These parameters include stack geometry,
gas temperature, velocity and moisture content.
Before any screening tests can be performed, all preliminary measurements
must be made, and the site prepared for sampling. Process data will be acquired
previous to a sampling run to determine which screening trains will be used.
3.2.2 Apparatus
Tape measure
Temperature gauge (Thermocouple, or equivalent, to measure stack
temperature to within 1.5 percent of the minumum absolute stack
temperature).
Pitot tube (Type S with a coefficient within + 5 percent over the
working range).
Differential pressure gauge (Inclined manometer, to measure velocity
head to within + 10 percent of the minimum value).
Barometer (To measure atmospheric pressure to within 0.1 inch Hg).
Probe* (Stainless steel or glass sufficiently heated to prevent
condensation, with glass wool plug to remove particulate matter).
Impingers* (Two midget impingers - 30 ml capacity).
Ice bath container* (To condense moisture in impingers).
Silica gel tube* (To protect pump and dry gas meter).
Pump* (Leak-free, diaphragm type, or equivalent).
Dry gas meter (To measure within 1 percent of total sample volume).
Graduated cylinder (25 ml).
Balance - Triple beam.
Wet bulb dry-bulb apparatus.
Orsat apparatus.
*0ptional - needed only if condenser method for moisture determination is used.
55
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3.2.3 Reagents
Distilled water
Silica Gel (Indicating type)
Orsat solutions
3.2.4 Stack Geometry, Temperature and Gas Velocity Measurements
a. Select the sampling site and number of traverse points required
according to accepted procedures, as shown in Reference 3.
Circular stacks will require two sample ports located 90 degrees
apart. The number of sample ports for rectangular stacks is
determined by the cross-sectional area Cequivalent diameter)
and flow characteristics. It is preferable to locate the
sample ports on a vertical run whenever possible. When the
flues are under a negative draft, standard 3-inch couplings
with caps are sufficient.
b. Measure the inside diameter of the stack. For rectangular
stacks, use the following equation to calculate the equivalent
diameter:
Equivalent Diameter - 2 (length x width)
length + width
c. Perform a standard velocity traverse and measure the absolute
pressure in the stack. A thermocouple should be attached to
the tip of the pitot tube during the traverse. Record the
temperature and velocity head at each traverse point.
d. Calculate the average velocity head and temperature of the
stack and record these values. These data will be used later
to calculate the sampling flow rate according to procedures
given in Reference 4.
3,2.5 Moisture Content
3.2.5.1 Wet Bulb - Dry Bulb Method
Moisture content may be measured by the wet bulb-dry bulb method if
the dry bulb temperature is below 212 F and it is expected that the percentage
of moisture will be below 15 percent. A psychometric chart and instructions
for use of the apparatus are included in the wet bulb-dry bulb sampling kit.
56
-------
If it is obvious that the gas stream is saturated with moisture (presence of
liquid droplets in the gas stream), use the average stack temperature calculated
in Section 3.2.4, and the psychometric chart to determine the percent moisture.
3.2.5.2 Condenser Method
When the above methods cannot be used, the condenser method must be
used. This procedure is detailed in Reference 3.
3.2.6 Gas Composition
Measure the stack gas composition using an Orsat analyzer.
57
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3.3 SCREENING PROCEDURES WITH CARBON
3.3.1 Introduction
Any gas or vapor (adsorbate) will adhere to some degree to any solid
surface (adsorbent) due to the van der Waals forces which are encountered on
the surface of the solid. This phenomenon is known as physical adsorption.
Sometimes an adsorbate will become chemically bonded to the adsorbent (chemi-
sorption).
Adsorption (chemical and/or physical) as an air pollution control
method is used as a means of concentrating objectionable or toxic substances,
thus facilitating their disposal or recovery. True gases such as hydrogen,
nitrogen, oxygen, carbon monoxide and methane are virtually nonadsorbable at
ambient temperatures by physical means. Low-boiling vapors (B.P.-100° to
0 C) are moderately adsorbable and adsorption efficiency can be increased by
refrigeration. Heavier vapors (B.P. Q°C) are readily adsorbed by activated
carbon at ordinary temperatures. In general, the higher the molecular weight
and/or critical temperature, the greater the weight capacity and preference.
Aromatic and/or non-polar gases are preferentially adsorbed. At 50 percent
humidity or lower, water vapor present in a gas stream generally will not
affect adsorption capacities for other materials and will provide some cooling
of the carbon bed.
Activated carbon is used in CAD for removal of low concentrations
( 1%) of organic and inorganic pollutants. High concentrations would rapidly
overload the carbon dose used in screening. In commercial practice, carbon is
not normally used for removal of high concentrations of pollutants because of
the higher costs of large carbon systems and regeneration equipment.
Condensation is a potential technology to reduce organic loading,
and this option can be conveniently added to the screening system. Gas cooling
also becomes necessary to protect the carbon from high temperatures and
concomitantly, to reduce desorption. When needed, the gas cooling module can
be standard SASS equipment.
Particulate, when present, should be removed to prevent plugging of
the carbon bed. Tars, oils and gummy material, in particular, will coat the
carbon and reduce the available surface area. The standard SASS cyclone and
filter section may be used as the particulate removal module.
58
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3.3.2 Summary of Method
Stack gases are passed through a heated probe to a series of heated
cyclones and a final filter, all housed in a 400 F oven, for removal of
particulate matter when required. Next, the gases are cooled by passing
through a water-cooled condenser. The gas stream, at a temperature of 130 F
or less, is passed through a canister filled with activated carbon. The
treated stream is then pulled through a modified SASS train which will collect
all components not removed by activated carbon.
3.3.3 Apparatus
The list of apparatus needed for gaseous emission screening with the
carbon column is given below:
1. Standard SASS train;
2, Grab sampling bulb - 3 liter capacity, fitted with a stopcock
valve and sample probe (Figure 7);
3. A canister - To contain 4.5 kg of activated carbon; 6-inch
diameter cylinder 24 inches in length, and
4, Grab sampling bulb - 3 liter capacity, fitted with two stopcock
valves (Figure 9).
Note: The pumps, probes, gas meters, temperature and pressure
gauges, etc., which are available in a Standard SASS train,
will be utilized during the screening tests.
3.3.4 Reagents
1. Silica gel - Indicating type, 3 to 8 mesh (2 kg)
2. XAD-2 - Sorbent resin (500 gms)
3. 30 percent solution HO- - (1 liter)
4. 0.02M silver nitrate - (1 liter)
5. 0.02M ammonium persulfate - (1 liter)
6. Activated carbon - Calgon type BPL or equivalent - (5 kg)
3.3.5 Preparation
See Section 3.2 before proceeding with screening train preparation.
Figure 8 shows the configuration of the train to be used for carbon
evaluation. Assemble the components of the train as shown. Detailed in-
structions for set-up of standard SASS train items are included in Reference 4.
59
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TEFLON TUBE TO ACT AS NOZZLE
PYREX WOOL PLUG
\
STYROFOAMn
PROTECTOR
EVACUATED
3 UTER
FLASK
Figure 7. Grab sampling bulb.
-------
STANDARD
SASS TRAIN
CONDENSER
MODULE
4 4.
XAD
PARTICULATE
REMOVAL
DRY
ORIFICE GAS
METER
PUMPS
Figure 8. Carbon screening train.
-------
STYROFOAM —,
PROTECTOR
N>
3 LITER
VESSEL
Figure 9. Grab sampling bulb with dual stopcock arrangement,
-------
The following steps are necessary to prepare the train for sampling:
1. Place a filter in the filter holder;
2. Place approximately 5 kg of activated carbon into the carbon
canister and seal;
3. Place 130 gms of XAD-2 and 500 gms of silica gel in their
respective canisters and seal;
4. Perform the standard leak test as required by Level 1 protocol,
and replace or repair any components which do not meet leak
testing requirements; and
5. Transport the equipment to the test site.
Arrangements should be made at this time for gathering of process
operation data during the sampling period. Be sure that an adequate supply of
ice is available (each train may require as much as 100 Ibs/hr during the
sampling period). Using the preliminary data obtained in section 3.2 of this
procedure, calculate the required sampling nozzle size and sample flow rate,
as shown in Reference 4. Attach the nozzle to the probe and perform a leak
test to assure that the equipment was not damaged during transportation to the
site. Energize all components which require heating/cooling, i.e. probe,
cyclone oven, gas cooling device. When these components have attained the
designated temperatures, proceed to section 3.3.6.
3.3.6 Sampling Procedure
Place the probe in the stack and position the nozzle at the point of
average velocity. Record all necessary train operation data (gas meter reading,
temperatures, stack gas flow rate). Start the pumps and set the sampling flow
rate to the proper value as calculated from the average velocity data and
nozzle size. Operate the train until a minimum of 1000 cubic feet of gas has
been sampled, as indicated by the gas meter. If particulate build-up causes
a severe increase in vacuum and corresponding drop in sample flow rate, the
test must be halted to replace the filter. Monitor the temperatures through
the condensate trap and the impinger train. The gas temperature leaving the
condensate trap should not be allowed to exceed 130°F. Condensate will build
up in the trap and must be transferred periodically to the condensate collection
bottle. The detailed procedure is given in Reference 4.
63
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3
Toward the end of the sample run (900 to 1,000 ft sampled) a 3-
liter grab sample will be taken for GC analysis. This is accomplished by
placing a 3-liter sampling bulb in line and momentarily diverting the gas flow
through the bulb (Refer to Figure 9). Open valves 2 and 3 and then close
valve number 1. Leave the valves in this position for one minute to ensure
proper flushing of the sample container. After the sample has been taken,
open valve 1 and close valves 2 and 3.. Remove the bulb from the line and
transport to the van for GC analysis. Level 1 procedures are used to analyze
for low-molecular weight hydrocarbons in this sample.
When sufficient sample volume has been collected by the train, shut
down the pumps by first closing the coarse control valves. When the vacuum
gauge has dropped to zero, the pump switches may be turned off. Record the
final gas meter reading and all temperature readings.
3.3.7 Sample Handling Procedures
Remove the probe from the stack and turn off all heating/cooling
elements. Opening the oven door will speed cooling of the oven and contents.
Remove the XAD-2 cartridge, seal the ends, tag the sample and submit for Level
1 analysis. Remove the cyclone and filter assembly, discard the collected
particulate matter and clean all surfaces. Remove the silica gel from its
canister and clean the container. Transfer the condensate sample to a separa-
tory funnel. Using a pH meter, adjust the pH to 7.0 with ammonium hydroxide
or hydrochloric acid. Extract the sample with three 50-ml portions of methylene
chloride. Tag this sample and submit as "Organic Extract." Divide the remaining
aqueous sample into two equal parts. Using a pH meter, adjust each part as
follows:
Part A - Acidify to pH less than 2 with nitric acid.
Part B - Adjust pH to 12 with sodium hydroxide.
Transfer each part to a suitable size polyethylene bottle for shipment to the
home laboratory.
Empty the carbon canister and discard the spent carbon.
64
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3.4 GAS SCREENING PROCEDURES WITH SCRUBBING MODULE
3.4.1 Introduction
Wet scrubbing is a term used to broadly describe vapor-liquid mass
transfer operations. In scrubbing, one or more components are removed from
the gas phase by absorption into the liquid phase. Absorption depends on a
solubility mechanism but may be followed by chemical reaction once in solution.
Absorption is enhanced by high diffusion rates, high solubilities, large
interfacial areas and turbulence. Numerous equipment designs are commercially
available which promote contact of the vapor and liquid.
Scrubbing methodology for gaseous emission CAD is designed primarily
for the removal of acidic pollutants in the gas stream. Some organic components
will also be absorbed. Among the aqueous alkaline scrubbing media investigated
were caustic soda, lime, carbonate, magnesia and ammonia. Organic sorbents
were not considered because they are generally operated under high pressure
and/or low temperature. Sodium carbonate was selected as a broad base sorbent
with the advantage of being insensitive to high concentrations of C0_. Carbon
dioxide is a major component in many sources of possible interest to CAD.
Design for C02 removal, in addition to other priority pollutants, would result
in excessively large equipment and solution requirements.
The scrubber module is a packed column, 4-inch dia. and 5-ft long,
containing a 3-ft depth of 1/2-inch Raschig rings. Scrubbing solution (2-M
sodium carbonate - 16 liters) will be recirculated through the packed column
until the pH drops to 10.0, when the test will be stopped to replace the spent
solution.
Preceding the scrubber module are gas cooling and particulate
removal modules. These were described in Sections 3.1 and 3.3.
The sampling portion of the overall train contains the SASS sorbent
module (XAD-2), for collection of organic components not removed in screening,
and the SASS impinger module for collection of inorganic components.
3.4.2 Summary of Method
Stack gases are passed through a series of cyclones and final filter,
all housed in a heated 400°F oven. The gas is then cooled to 13Q°F in a
water-cooled condenser. Gases next pass through a scrubber module consisting
65
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of a packed tower utilizing a counter-current flow of alkaline solution.
Leaving the screening section of the train, the treated gas enters the sampling
section where standard SASS modules will collect any remaining pollutants.
3.A.3 Apparatus
For a list of apparatus needed for gaseous emission screening with
the scrubber column, refer to Section 3.3.3, Delete item 3, (the carbon
canister) and add the following:
1. Scrubber column - 4-inch diameter by 5 feet in length, packed
with 1/2-inch Raschig rings (3 feet of packing); and equipped
with a 16-liter reservoir and recirculation pump (See figure
10); and
2, pH meter and probe.
3.4.4 Reagents
For a list of reagents needed for gaseous emission screening with
the scrubber column, refer to Section 3.3.4. Delete item 6 (activated carbon),
and add the following:
1. 2-M sodium carbonate - (.16 liters). Make an additional batch
(16 liters) for replacement solution; and
2. Fiberglass filters - (142 mm x 0.016 inch).
3-4.5 Prejjara t ion
See Section 3.2 before proceeding with screening train preparation.
Figure 11 depicts the configuration of the train to be used for
scrubber evaluation. Assemble the components of the train as shown. Detailed
instructions for set-up of standard SASS train items are included in Reference 4,
The following steps are necessary to prepare the train for sampling:
1. Place a filter in the filter holder;
2. Fill the scrubbing solution reservoir with sodium carbonate
solution - approximately 16 liters;
3, Place 130 gras of XAD~2 resin in the appropriate canister and
seal;
4. Fill the standard SASS impingers with appropriate reagents;
66
-------
1/2"
SCRUBBER
TOWER
4"DIAM5-0"HIGH
WITH 1/2" BERL
SADDLES
1/2"
GAS INLET-I
(FROM CONDENSATE
MODULE)
SOLVENT
COLLECTION
VESSEL
16 LITERS
GAS OUT
(TO NEXT MODULE)
SOLVENT CIRCULATION
PUMP I LPM
Figure 10. Detail of scrubber.
67
-------
STANDARD
SASS TRAIN
oo
c
E
CONDENSER
MODULE
F*RTICULATE
REMOVAL
@—I X AD-27 IMPINGE RS
t i*
T
ORIFICE DRY PUMPS
GAS
METER
Figure 11. Scrubber screening train
-------
5. Perform the standard Leak test as required by Level 1 protocol,
and replace or repair any components which do not meet leak
testing requirements; and
6. Transport the equipment to the test site.
Arrangements should be made at this time for gathering of process
operation data during the sampling period. Be sure that an adequate supply
of ice is available (each train may require as much as 100 lbs/hr during the
sampling period). Using the preliminary data obtained in Section 3.2 of this
procedure, calculate the required sampling nozzle size and sample flow rate,
as shown in Reference 4. Attach the nozzle to the probe and perform a leak
test to assure that the equipment was not damaged during transportation to
the site. Turn on the scrubber solution recirculation pump and set the flow
to approximately 1 liter/minute. Energize all components which require
heating/ cooling, i.e., probe, cyclone oven, gas cooling device. When these
components have attained the designated temperatures, proceed to Section 3.4.6.
3.4.6 Sampling Procedure
Place the probe in the stack and position the nozzle at the point
of average velocity. Record all necessary train operation data (gas meter
reading, temperatures, stack gas flow rate). Start the pumps and set the
sampling flow rate to the proper value as calculated from the average velocity
data and nozzle size. Operate the train until a minimum of 1,000 cubic feet
of gas has been sampled, as indicated by the gas meter. If particulate
build-up causes a severe increase in vacuum and corresponding drop in sample
flow rate, the test must be halted to replace the filter. The scrubbing
solution should also be replaced at this time. Monitor the temperatures
through the condensate trap and the impinger train, and the pH of the scrubbing
solution. A pH of less than ten is not acceptable and the scrubber solution
should be replaced if the pH drops below ten. Condensate will build up in
the trap and must be transferred periodically to the condensate collection
bottle. The detailed procedure is shown in Reference 4.
3
Toward the end of the sample run (900 to 1,000 ft sampled) a
3-liter grab sample will be taken for GC analysis. This is accomplished by
placing a 3-liter sampling bulb in line and momentarily diverting the gas
flow through the bulb (Refer to Figure 9). Open valves 2 and 3 and then close
69
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valve number 1. Leave the valves in this position for one minute to ensure
proper flushing of the sample container. After the sample has been taken,
open valve 1 and close valves 2 and 3, Remove the bulb from the line and
transport to the van for GC analysis. Level 1 procedures are used to analyze
for low-molecular weight hydrocarbons in this sample.
When sufficient sample volume has been collected by the train, shut
down the pumps by first closing the coarse control valves. When the vacuum
gauge has dropped to zero, the pump switches may be turned off. Record the
final gas meter reading and all temperature readings.
3.4.7 Sample Handling Procedures
Remove the probe from the stack and turn off all heating/cooling
elements. Opening the oven door will speed cooling of the oven and contents.
Stop circulation of scrubbing solution. Remove the XAD-2 cartridge, seal the
ends, tag the sample and submit for Level 1 analysis. Remove the cyclone and
filter assembly, discard the collected particulate matter and clean all
surfaces. Transfer the condensate sample to a separatory funnel. Using a pH
meter, adjust the pH to 7.0 with ammonium hydroxide or hydrochloric acid.
Extract the sample with three 50-ml portions of methylene chloride. Tag this
sample and submit as "Organic Extract." Divide the remaining aqueous sample
into two equal parts. Using a pH meter, adjust each part as follows:
Part A - Acidify to pH less than 2 with nitric acid.
Part B - Adjust pH to 12 with sodium hydroxide.
Transfer each part to a suitable size polyethylene bottle for shipment to the
home laboratory.
The spent sodium carbonate solution may be discarded at this time.
Clean-up of the remainder of the train should follow procedures
specified by Level 1.
70
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3.5 GAS SCREENING PROCEDURES WITH SCRUBBING AND CARBQN ADSORPTION MODULES
3.5.1 Introduction
Scrubbing and carbon adsorption are presented individually in
Sections 3.3 and 3,4 as the basic control technologies for CAD gaseous emission
methodology. When these two operations are run in series with particulate
removal and condensation, the total screening system offers the most versatile
CAD approach to a complex gas stream containing all classes of pollutants.
If process knowledge of a source under investigation is inadequate to lead to
the proper selection of a simpler system, the total train should be specified.
A complete set of Level 1 samples can be recovered from the total
train configuration. Analyses of residual pollutants captured by the SASS
sorbent and impinger modules will indicate the effectiveness of the combined
screening operations for removal of pollutants. The individual effectiveness
of the carbon or scrubber module can be determined by analyzing the grab
samples taken before and after each module.
3.5.2 Summary of Method
Stack gases are passed through a series of screening operations and
into a sampling section, as illustrated in Figure 12 and under conditions
described in Sections 3.3.2 and 3.4.2.
3.5.3 Apparatus
The combined screening train utilizes all of the modules required
for the scrubber and the carbon screening tests. The list of apparatus
required as presented in Sections 3.3.3 and 3.4.3.
3.5.4 Reagents
The list of required reagents for the combined screening test is
presented in Sections 3.3.4 and 3.4.4.
3.5.5 Preparation
See Section 3.2 before proceeding with screening train preparation.
Figure 12 shows the configuration of the train to be used for the
combined scrubbing and carbon adsorption evaluation. Assemble the components
of the train as shown. Detailed instructions for set-up of standard SASS
train items are included in Reference 4. The following steps are necessary
to prepare the train for sampling;
71
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STANDARD
SASS TRAIN
N>
U
CONDENSER
MODULE
Jf
PARTICIPATE
REMOVAL
STANDARD
IMPINGER
MODULE
ORIFICE DRY PUMPS
GAS
METER
Figure 12. Combination scrubbing and carbon adsorption screening train.
-------
1. Place a filter in the filter holder;
2. Fill the scrubbing solution reservoir with sodium carbonate
solution (approximately 16 liters).
3. Place 13Q gms of XAD^-2 resin in the appropriate canister and
seal;
A. Place approximately 5 kg of activated carbon into the carbon
canister and seal;
5. Fill the standard SASS impingers with appropriate reagents;
6. Perform the standard leak test as required by Level 1 protocol,
and replace or repair any components which do not meet leak
testing requirements; and
7. Transport the equipment to the test site.
Arrangements should be made at this time for gathering of process
operation data during the sampling period. Be sure that an adequate supply
of ice is available (each train may require as much as 100 Ibs/hr during the
sampling period). Using the preliminary data obtained in Section 3.2 of this
procedure, calculate the required sampling nozzle size and sample flow rate,
as shown in Reference 4. Attach the nozzle to the probe and perform a leak
test to assure that the equipment was not damaged during transportation to
the site. Turn on the scrubber solution recirculation pump and set the flow
to approximately 1 liter/minute. Energize all components which require
heating/ cooling, i.e., probe, cyclone oven, gas cooling device. When these
components have attained the designated temperatures, proceed to Section 3.5.6.
3.5.6 Sampling Procedure
Place the probe in the stack and position the nozzle at the point of
average volocity. Record all necessary train operation data (gas meter reading,
temperatures, stack gas flow rate). Start the pumps and set the sampling flow
rate to the proper value as calculated from the average velocity data. Operate
the train until a minimum of 1,000 cubic feet of gas has been sampled, as
indicated by the gas meter. If particulate build-up causes a severe increase
in vacuum and corresponding drop in sample flow rate, the test must be halted
to replace the filter. The scrubbing solution should also be replaced at
this time. Monitor the temperatures through the condensate trap and the
impinger train and the pH of the scrubbing solution. A pH of less than ten is not
73
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acceptable and the scrubber solution should be replaced if the pH drops below
this value. Condensate will build up in the trap and must he transferred
periodically to the condensate collection bottle. The detailed procedure is
shown in Reference 4.
3
Toward the end of the sample run (900 to 1000 ft sampled) a 3-liter
grab sample will be taken for GC analysis. This is accomplished by placing a
3-liter sampling bulb in line and momentarily diverting the gas flow through
the bulb (Refer to Figure 9). Open valves 2 and 3 and then close valve
number 1. Leave the valves in this position for one minute to ensure proper
flushing of the sample container. After the sample has been taken, open
valve 1 and close valves 2 and 3. Remove the bulb from the line and transport
to the van for GC analysis. Level 1 procedures are used to analyze for low-
molecular weight hydrocarbons in this sample.
When sufficient sample volume has been collected by the train, shut
down the pumps by first closing the coarse control valves. When the vacuum
gauge has dropped to zero, the pump switches may be turned off. Record the
final gas meter reading and all temperature readings.
3.5.7 Sample Handling Procedures
Remove the probe from the stack and turn off all heating/cooling
elements. Opening the oven door will speed cooling of the oven and contents.
Stop circulation of scrubbing solution. Remove the XAD-2 cartridge, seal the
ends, tag the sample and submit for Level 1 analysis. Remove the cyclone and
filter assembly, discard the collected particulate matter and clean all
surfaces. Remove the silica gel from its canister and clean the container.
Transfer the condensate sample to a separatory funnel. Using a pH meter,
adjust the pH to 7.0 with ammonium hydroxide or hydrochloric acid. Extract
the sample with three 50-ml portions of methylene chloride. Tag this sample
and submit as "Organic Extract". Divide the remaining aqueous sample into
two equal parts. Using a pH meter, adjust each part as follows:
Part A - Acidify to pH leas, than 2 with nitric acid.
Part B - Adjust pH to 12 with sodium hydroxide.
Transfer each part to a suitable size polyethylene bottle for shipment to the
home laboratory.
The spent sodium carbonate solution and the spent carbon may be
discarded at this time.
74
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SECTION 4
SOLIDS METHODOLOGY
4.1 BACKGROUND
Solid wastes generated at coal conversion plants may be the most
variable of the multimedia discharges, both in form and composition. They
usually consist of highly concentrated pollutants combined in residues from
wastewater and gas treatment technologies in addition to the unwanted materials
present in coals, minerals and ores processed for fuel value and/or metal
content. Types of waste solids include:
1) Residues from the conversion processes including accompanying
unrecovered carbon or hydrocarbons;
2) Residues from coal combustion processes/power generation;
3) Spent catalysts from shift conversion, methanation or catalytic
synthesis reactors, liquefaction reactors, hydrotreatment and
liquids products upgrading (e.g., reforming and hydrocracking);
4) Tar and oil sludges;
5) Filter precoat materials and filtered solids; and
6) Solids and sludges from air/water pollution control operations.
Not included above are solids which are often utilized as marketable
byproducts and do not require further treatment or consideration for final
disposal. An example is elemental sulfur recovered from gas cleanup processes
such as Glaus and Stretford. Similiarly, many catalysts are of significant
value to justify regeneration for recycle. In such cases, air emissions
and/or wastewaters are usually produced*
Comparatively few options are available for the safe disposal of
solid materials containing toxic or problem components. Principally, these
are incineration, fixation or encapsulation, and landfilling. Landfilling is
normally the ultimate means of final disposal. Incineration usually produces
an ash, and often a sludge when scrubbing for emission control is required.
75
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These residues require final disposal such as landfilling. Fixation and
encapsulation processes typically treat the solid to produce an inert (relatively
non-1eachable) material suitable for final disposal. Solids which have
stable characteristics or which are considered harmless to the environment
may be landfilled without treatment or utilized for construction materials
and land reclamation. If pollution from leachate is a possibility, a controlled
landfill area (with an impermeable bottom liner and a runoff-collection
system) will be required.
76
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4.2 SCREENING PROCEDURES
4.2.1. Applicability
Incineration of solid wastes, can take several forms such as high
temperature thermal destruction, catalytic destruction, pyrolysis and wet air
oxidation. It is impractical to consider outfitting a mobile CAD test facility
with bench scale equipment to evaluate the effects of these types of processes.
Sampling and measurement of residue and resultant stack gases are difficult
and costly and may not yield useful data unless the test is run under the
(larger scale) conditions employed in incineration studies used to develop
design criteria for scale-up.
Chemical fixation of encapsulation techniques are proprietary in
nature and could not be satisfactorily duplicated in a CAD facility. Samples
would have to be forwarded to a selected process vendor if data are to be
developed. This approach is not reasonable until Level 1 S/A data establish
the need for treatment.
Based on the foregoing factors, CAD evaluation of the effects of
incineration and fixation/encapsulation as solids handling/disposal techniques
using screening test procedures is not included in the CAD program. An
additional Level 1 S/A test is recommended (Section 4.2.3).
The CAD solids methodology does not incorporate a screening procedure
for generating leachate from solids or semi-solids slurries. A review of the
published literature showed that the practices and techniques reported by
other investigators were generally too long in testing time to be considered
for CAD. Also, there was considerable subjectivity in the approaches employed
by each researcher. Suggested testing for leachate are shown in Sections
4.2.2. and 4.2.3.
4.2.2. Current Testing
Primary concerns connected with solids disposal by landfill are the
quantity and quality of the leachate, and its subsequent effect on subsurface
waters (presuming the landfill is unlined). Leaching tests to generate a
water sample are specified in Level 1 S/A protocols and need not be performed
in the field as part of CAD,, Two leachate samples are developed in Level 1:
one from extraction with deionized water, and a second using dilute hydrochloric
77
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acid solution* It is recommended that data from these determinations (with
suggested supplemental testing! be used for evaluation of leachate impact on
the environment. If adverse effects on groundwater are shown to be likely,
an impermeably lined basin will have to be anticipated (conceptually) and
leachates processed as an aqueous waste stream.
4.2.3 Supplemental Testing
As an addition to the leachate testing currently performed under
Level 1 S/A procedures (Section 4.2.2), it is recommended that a third leaching
medium be added. The extractant should be a dilute alkaline solution, such
as ammonium hydroxide. The purpose of this is to produce a leachate which
might result if the solids were in contact with alkaline conditions at a
landfill site.
Another test not presently indicated in Level 1 S/A procedures is
the determination of the fuel value of a solid. When considering incineration
as a potential treatment technology, it is necessary to know the fuel value
in order to evaluate the economics of the option and get an indication of
supplementary fuel requirements. Fuel value is easily determined using
standard methods and a bomb calorimeter.
The Level 1 S/A sample size of one (1) kilogram presently specified
should be sufficient to accommodate the additional heat value testing recommended.
Although not included in CAD procedures at this time because of its
tentative status, reference is nevertheless made to an "Extraction Procedure"
(EP) proposed by the EPA for developing leachates from toxic wastes (Federal
Register; Vol 43; No. 243; Dec. 18, 1978). If the EP is eventually adopted
as a standard investigative procedure, it will be a candidate for inclusion
in the CAD solids methodology in the future.
78
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SECTION 5
LABORATORY VERIFICATION
During the formulation of Control Assay Development (CAD) methodologies,
it became apparent that certain methods should be verified in the laboratory
before being adopted for use in the final procedures.
The objectives of the laboratory study were:
1. To determine logistical problems of sample handling;
2. Assess the adequacy of the proposed designs and operation of
appropriate test units;
3. Verify the use of a dry bacterial culture for biological
oxidation studies; and
4. Evaluate the feasibility of using SASS components for air
testing.
CAD field procedures for coal conversion wastewater treatment
require the processing of relatively large volumes of water as compared to
standard process development testing procedures for determining treatability
of a given waste. Volumes of 400 liters or more have to be processed to
accommodate normal system requirements and to make samples available for IERL
Level 1 analyses which require 10 liters from each unit process tested.
Figure 13 indicates the processes initially selected for testing wastewater by
CAD methods.
To accomplish the proposed objectives for the wastewater treatment
portion of CAD, a 200-liter synthetic wastewater sample was processed as it
would be by a sampling team in the field. Level 1 analytical procedures were
not applied to the treated samples because of time and cost restrictions.
Rather, traditional wastewater parameters (COD, BOD, solids and metals analyses)
were used to measure/monitor the performance of each unit process. Separate
studies were conducted to determine the effectiveness of using dry bacteria
versus an acclimated activated sludge for the biological oxidation assessment.
79
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SOURCE A
SOURCE B
1
BYPRODUCT
REMOVAL
I
COMPOSITE SAMPLE
FOR
LEVEL I
ASSAY
I
SOLIDS SEPARATION
BIO-OXIDATION
CARBON ADSORPTION
ION EXCHANGE
CHEMICAL OXIDATION
CARBONI
ADSORPTION i
+- a
-»- 3
-»- 4
ION EXCHANGE
B
Figure 1. Initial wastewater test sequence.
80
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CAD air methodologies specify the use of a modified Source Assessment
Sampling System (SASS). The minimum sample volume required by IERL Level 1
air analyses for particulates, organic and inorganic materials is 1000 cubic
feet. This volume allows for collection of sufficient quantities of trace
components to reach detectable levels.
In order to evaluate the feasibility of modifying a SASS train for
CAD purposes, a unit was borrowed and subjected to various tests to determine
whether the system would have enough inherent capacity to cope with an increased
pressure drop caused by supplemental CAD testing modules. Several tests were
conducted using a prepared gas mixture to verify the efficiency of the proposed
scrubbing unit and the carbon adsorption canister. Figure 19 indicates the
air screening tests required by CAD methodologies*
This report summarizes the results and conclusions of the laboratory
verification studies for both air and water methodologies.
81
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SECTION 6
WASTEWATER SCREENING
6.1 SYNTHETIC WASTEWATER COMPOSITION
Because of the difficulty of obtaining an actual coal conversion
process waste, it was decided to use a synthetically prepared waste for the
laboratory verification studies. The organic portion of the synthetic wastewater
used for verification purposes was derived from a formulation developed by
Dr. Philip Singer from research conducted at the University of North Carolina
at Chapel Hill . The concentrations of organic compounds proposed by Dr. Singer
defined a coal gasification wastewater with no byproduct recovery steps.
Since the laboratory verification was intended to test CAD methodologies after
byproduct recovery, the initial organic concentrations were modified to simulate
(&\
a phenol recovery step. The Phenosolvan^-'process was selected as a typical
phenol extraction process. Extraction recoveries expected from this process
were estimated to be 6 :
99.5% for monohydric phenols
60.0% for polyhydric phenols
5.0% for other organics
The phenolic compounds listed for waste A (Table 6) were segregated
by chemical structure, and values of 90% and 50% removal were used to calculate
the concentrations remaining after byproduct recovery of monohydric and polyhydric
phenols, respectively. No concentration adjustments were made for "other
organics."
The inorganic components of the synthetic mix were selected after
reviewing actual sample data from several operating plants. Table 7 lists the
target inorganic concentrations in the synthetic mixture.
82
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TABLE 6
ORGANIC COMPOSITION OF SYNTHETIC WASTE
Compound
Waste A
Concentration mg/1
Synthatic Waste
Concentration mg/1
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
15.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
Phenol
Resorcinol
Cat echo 1
Acetic Acid
o-Cresol
p-Cresol
3,4 Xylenol
2,3 Xylenol
Pyridine
Benzole Acid
4-Ethylpyridine
4-Methylcatechol
Acetophenone
2-Indanol
Indene
Indole
5-Methylresorcinol
2-Naphthol
2,3,5 Trimethylphenol
2-Methylquinoline
3,5 Xylenol
3-Ethylphenol
Aniline
Hexanoic Acid
1-Naphthol
Quinoline
Naphthalene
Anthracene
20.00
1QOO
1000
400
400
250
250
250
120
100
100
100
50
50
50
50
50
50
50
40
40
30
20
20
20
10
5
Q.2
200
500
500
400
40
25
25
25
120
100
100
50
50
-
50
50
25
50
5
40
4
3
20
20
20
10
5
0.2
83
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TABLE 7
INORGANIC COMPONENTS
OF SYNTHETIC WASTE
Component Concentration (mg/1)
F 2.0
Fe 0.2
pb 0.04
HS 0.007
P°A 2.5
S 12.0
Zn 0.08
As 0.2
Cd 0.02
Cr 0.03
Cu 0.1
CN" 1,0
84
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One major problem encountered with the use of the synthetic wastewater
mixture was noted early in the study was a loss of COD organics on standing.
This situation is discussed in the "Biological Oxidation" section of this
report.
A second phenomenon observed during CAD verification testing was the
continued precipitation of solids in the synthetic waste as it aged.
The foregoing situations prompted appropriate revisions in the
Control Assay (CA) screening procedures and CAD methodologies initially
conceived.
6.2 SOLIDS SEPARATION
6.2.1 Initial Concepts
The removal of suspended solids from a wastewater sample (Primary
Treatment) may be accomplished by several methods. They can include: chemical
coagulation and flocculation, gravity separation, physical straining, cen-
trifugation, and filtration through granular media. Suspended solids removal
for CA screening requires only that solids be removed to a level that will not
interfere with subsequent unit operations.
Jar tests using chemical coagulants are a common laboratory procedure
for solids separation. However, these tests can be time consuming because of
the need to evaluate various types and combinations of flocculants. In addition,
the flocculants eventually selected can chemically alter the composite wastewater
test sample, thereby adding unnecessary constituents to the IERL Level 1
analysis samples. Consequently, solids separation via chemical treatment was
discounted as not being attractive as a CA screening procedure.
Four candidate approaches were considered for separation of solids
by physical means; centrifugation, sand filtration, microstraining, and
cartridge filtration. Although it was felt that all the above physical
separation methods would be applicable, the first three were discarded after
evaluation of various factors including: degree of solids removal required;
the kind of specialized apparatus needed; the question of logistics for
storing, transporting, and obtaining new filter media; the ease of operation;
and the reproducibility of results.
85
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6.2.2 Selected Alternative
Filtration of the composite sample using a polypropylene cartridge
was deemed to be the most favorable method for solids removal in the CA
screening procedure. A pore size of 75 microns was selected as being descriptive
of the particle size discharged from a well-designed primary settler.
6.2.3 Test Work
A 200-liter sample of synthetically prepared waste was passed
through the cartridge filter with no difficulty. The synthetic waste typically
had a fairly low suspended solids level at the outset and no problems with
filter plugging were encountered. It was noted, however, that the waste did
exhibit a tendency to precipitate solids from solution upon standing.
Several filtrations were made at various times during the laboratory
study and the 200-liter sample could be passed through the filter in 15
minutes or less using a standard laboratory pump. The aeration which occurred
due to the pumping action caused some foaming in the sample, but this situation
was not considered to be a significant problem.
6.2.4 Discussion of Results
It is possible that actual wastewater samples will have a much
higher level of solids than was encountered in the synthetic waste. Also,
during chemical pretreatment for byproduct recovery, conditions could develop
under which precipitates might be formed, thereby increasing the total amount
of suspended solids in the sample. Laboratory verification testing did not
include the byproduct removal steps embodied in the CAD test sequence (Figure 13).
The filter cartidges are relatively inexpensive and easy to change
when their filtering capacity has been exhausted. It would be possible to
make several filter changes during a run, if it became necessary, without a
significant loss of time. Cartridge filters are also available in various
pore sizes, and two or more filters of gradually decreasing size could be used
in series to obtain a higher degree of solids removal, if required. The
synthetic waste had no visible effect on the integrity of the cartridge or the
filter holder (both polypropylene). Solids removal by cartridge filtration is
recommended for use in CA screening procedures.
86
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6.3 CARBON ADSORPTION
6.3.1 Initial Concepts
Removal of soluble organic compounds by activated carbon adsorption
is encountered with increasing frequency as a process for wastewater treatment.
Carbon installations exist whose purposes range from use as a polishing step
for removal of trace concentrations of pollutants, to facilities for pretreat-
ment of waste at source prior to further processing. Compounds exhibiting
highly polar properties and having relatively high molecular weights are
generally most amenable to removal by activated carbon.
Evaluation of the effects of activated carbon as a unit operation
involves selection of a particular carbon; measurement of adsorptive capacity
using batch isotherms; and development of a breakthrough curve and regenerability
characteristics as determined from a continuous-flow pilot column test. In a
detailed concept design study, a number of different carbons are examined
using a particular wastewater before the best candidate is selected for the
column tests. Considering the basic purposes for CA screening procedures and
the field time constraints imposed, the use of a single, somewhat broad-based
carbon is proposed. This approach may not produce data using the best-suited
carbon, but the results will be sufficiently indicative of the applicability
of carbon as a treatment step, and will still keep the investigations within
the bounds of logistic practicality.
Since it is a relatively simple matter to perform carbon isotherms
on wastewater samples in the field to determine the approximate organic loading
and optimum pH conditions for a specific wastewater, they ara included as a CA
pre-screening procedure. Results of isotherm testing provide useful guidelines
for the column test runs, in addition to the data they furnish directly.
Two methods were considered for treating the CA composite sample by
activated carbon: (1) continuous feeding through a series of carbon columns;
and (2) batch testing. Each batch treatment of a composite sample represents
only one equilibrium condition. Also, it is anticipated that a microfiltration
step for removal of suspended carbon fines would be necessary before subsequent
CA processing steps could be performed.
Pilot column testing normally requires continuous sampling throughout
the run at several points in the carbon system to determine wavafront movement
87
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TABLE 8
ACTIVATED CARBON TEST RESULTS
CARBON ISOTHERM RESULTS
Carbon Dose (M) COD Remaining (C) COD Removed (x) X/M
(gm/1 Sample) (*) (mg/1) (mg/1) (mg COD/gm Carbon) (**)
0 5000 0 0
1 4653 347 347
5 3931 1069 214
10 3657 1343 134
20 3259 1741 87
50 1866 3134 63
100 1000 4000 40
oo
00 (*) Corrected for 100 ml sample size used.
(**) Equivalent to Ib. COD adsorbed/1000 Ib. Carbon.
CARBON COLUMN TEST RESULTS
Run Linear Flow Loading Rate Influent Concentration Effluent Concentration (+) % Removal
Number Rate (ml/min.) (gpm/ft2) COD mg/1 BOD mg/1 COD mg/1 BOD mg/1 COD BOD
1A 190 2.3 6864 2200 1714 440 75 80
IB 190 2.3 1714 440 334 186 80 58
1 (A&B) 190 2.3 6864 2200 334 186 95 91
2 200 2.4 3581 1940 347 197 90 90
(+) Corrected for dilution water in columns.
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and breakthrough, which are among the data needed for an actual column design.
Since only a limited number of samples can be taken during CA testing, it is
not proposed, nor is it necessary, to conduct this detailed type of design
study for a Level 1 CA screening.
6.3.2 Selected Alternative
Based on the foregoing considerations, continuous column operation
was selected for use in CA screening procedures. However, the number of
samples to be collected was limited to the initial feed and the final effluent.
The volume of the initial feed to the carbon system will be the amount needed
to produce the analysis samples after the carbon test as well as from any
subsequent CA screening procedures, plus the amounts needed to displace "fill
water" in the test units. The feed volume will be contained in a single
vessel, pumped continuously through the carbon beds, and collected in another
vessel at the effluent end. After withdrawing an aliquot sample for subsequent
laboratory analysis, the remaining effluent becomes the influent for any CA
screening steps to follow. To determine general column operation parameters,
several isotherms are to be run on a small quantity of the feed sample prior
to the continuous run.
6.3.3 Test Work
Table 8 summarizes the results of the activated carbon verification
testing. A Freundlich isotherm was performed on the synthetic waste sample to
establish the effectiveness of carbon treatment and to gain some insight into
the amount of carbon required to produce acceptable organic removal rates. The
standard COD analysis was used as a measure of organic removal. The values of
X/M (quantity of COD adsorbed per unit weight of carbon) were calculated and
plotted versus concentration of residual COD in solution, as shown in Figure 14.
The plot of the data showed a definite break at carbon dosages of 20 gm/1 and
higher. The sudden change in slope indicated that two (or more) classes of
organics are present, which are not uniformly adsorable.
Carbon column runs were made using the column design specified by
the CAD wastewater methodology, namely, four 2-inch I.D. glass columns connected
in series, each charged to the three-foot level with activated carbon (7.8 Ibs
of carbon). The test sequence for CAD (Figure 13) required the use of carbon
at two points, before and after bio-oxidation. A synthetic wastewater was
89
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10
O
CM
s
CD
X
x|S
L_J I \ I ' LU
I03
C= RESIDUAL COO (mg/l)
10'
Figure T4 Carbon Isotherm plot.
90
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prepared in accordance with the compositions shown on Tables 6 and 7. After
filtration (described in "Solids Removal"), the sample was equally divided
(84 liters per each run) for use during the column tests.
In view of the apparent dual adsorption regimes demostrated by the
batch isotherm (Figure 14),it was decided to collect data during the first
test run in two stages. The 84 liters of filtered waste were pumped through
fresh carbon in the columns, and the effluent retained (Run A). After rebedding
the columns with new carbon, the effluent from Run A was used as the influent
to Run B.
The second portion of synthetic waste was treated by the bio-
oxidation CA screening procedure, and then fed to fresh carbon in the columns.
Results of this test are indicated as Run 2.
6.3.4 Discussion of Results
To varying degrees, carbon is effective in reducing the COD and BOD
of the synthetic waste sample in both applications. Referring to Table &, it
is seen that the combined Run 1 achieved essentially the same effluent COD
and BOD concentrations and percent removals as Run 2. It must be recalled,
however, that Run 1 was conducted in two stages and that twice the carbon was
bedded. The specified CA screening procedures are more closely simulated by
Run 1A (alone). The data show that substantially less (BOD/COD) organics are
removed than in Run 2, which follows bio-oxidation.
It can be postulated that lower molecular weight organics were not
retained in the four-column system but were captured in an eight-column set
up (wavefront effect). Apparently, the four-column system was able to produce
a better effluent quality after one pass by virtue of the reactions taking
place during the bio-oxidation CA procedure (described in a later section).
The run time required to process a 95-liter sample through the
2
four-column system at a superficial velocity of 2 to 3 gpm/ft is approximately
8 hours. By increasing the column size to 3-inch I.D., the sample could be
processed in slightly less than 3 hours at an identical superficial velocity.
On the other hand, the amount of carbon available would be increased more
than twice.
91
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One disadvantage of increasing the column size is that the dilution
factor from the "fill" water existing in the carbon bed at the beginning
of the run becomes larger in relation to the size of the sample being passed
through the columns. In any event, the dilution factor has to be considered
when interpreting test results, and should not substantially affect the
evaluation of activated carbon as a unit process, provided that a sufficiently
large sample is processed.
The synthetic waste demonstrated a tendency to form some additional
solids on standing, which were removed by the carbon bed. If real life
wastes react similarly, it may be necessary to perform a supplemental cartridge
filtration before feeding the sample to the columns to prevent bed blinding.
The column design was modified slightly, since plugging problems
arose using the original fritted glass support materials. These were removed
and replaced with 5Q-mesh screen which was satisfactory for all subsequent
runs.
The new design will be incorporated into the CA methodologies
together with the increased column diameter.
6.4 BIOLOGICAL OXIDATION
6.4.1 Initial Concepts
The original intent of wastewater treatment evaluation is to have a
CAD field team on-site to perform all CA aqueous screening procedures in a
time period of approximately one week. Standard biological treatability
testing using activated sludge normally requires two weeks to a month of
continuous operation for acclimation of the biomass to the specific waste
being studied. After acclimation, an additional 3 to 4 weeks of data gathering
under steady state conditions are required to provide system performance and
design parameters for that particular wastewater. CA screening procedures
are not developed for the purpose of obtaining design data, therefore, the
continuous sampling after acclimation is not necessary. However, to properly
evaluate a biological system as a unit process, it is imperative that an
acclimated seed be used.
The requirement for an acclimated seed on-site posed several problems.
A "wet" seed must be continuously aerated and provided with some type of feed
substrate during transportation to a plant and while on location. The possi-
bility of acclimating a sludge from a local municipal treatment plant was
also considered. While being a viable option, such an approach could introduce
92
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unwanted contaminants to the system, depending on the type of industrial
waste normally treated at the local plant. Biological sludge from a plant
which normally treats coke oven wastes would be more ideal, since components
of this type of wastewater are similar to many materials found in coal conversion
wastes. However, the likelihood of always being in a location near this type
of treatment plant would be small and could not be realistically incorporated
into the screening methods. In essence, it was desirable to determine if
there were any feasible alternatives to using a wet seed for the CA screening
procedure.
By private communication, one investigator reports experimentation
examining the possibility of quick-freezing activated sludge for subsequent
use. While interesting, the work is still in an early trial stage and the
results are too tentative for inclusion in a CA screening procedure at this
time. A second alternative is the use of dry bacterial cultures which are
offered commercially by several vendors.
Dry bacterial cultures are grown on an inert material. The organisms
are selectively mutated and segregated in accordance with their ability to
biologically degrade specific classes of compounds. One such culture is
purported to specifically oxidize phenolic compounds, cyanides and various
other similar contaminants. The culture is marketed in a dry powder form
and, according to the vendor, the organisms are reactivated when added to
warm water and aerated for 24 hours.
The dry bacterial culture route offers a potential solution for the
transportation and acclimation problems posed by CA methodology.
6.4.2 Selected Alternative
It was decided to test a commercial dry bacterial culture to ascertain
whether or not it would serve as a practical alternative for a wet seed,
and/or to try to establish a relationship between system performance using
dry bacteria as compared with a seed acclimated to a waste in the more usual
manner.
6.4.3 Test Work
Various tests were performed to evaluate biological screening
procedures. The tests were divided into two catagories: Batch testing and
continuous systems. Additionally, experimental work was conducted (1) to
-------
gain a better familiarity with the characteristics and application of the dry
bacterial culture; and (2) to explore some side issues that arose during the
test work, which were relevant to the overall bio-oxidation CA verification
procedures/CAD methodologies.
The batch tests were performed either in 2-liter glass beakers or
in 7-liter cylindrical, stainless steel containers. Vessels used for the
continuous systems testing were 7.5-liter capacity stainless steel tanks
fitted with baffle plates at the outlet and to provide a quiescent zone for
solids settling. The volume of the aerated portion of these tanks was about
6 liters.
An attempt was made to start a continuous system using the dry
bacterial culture. After several days of feeding with dilute synthetic
wastewater, there was no apparent biological growth. It was believed that
the bacteria were present as a dispersed growth and were being lost in the
effluent, since there was no measurable solids production in the system and
effluent COD values were consistently higher than the feed analyses. Millipore
filtration of the effluent samples did not significantly reduce the effluent
COD results.
During this preliminary work, it was also noted that the COD values
of the feed material, initially held in an open container, dropped markedly
over a period of several days. Loss of volatiles to the atmosphere was
strongly indicated.
Air stripping tests were performed on batch samples of the synthetic
waste to quantify the COD material lost (presumably) by volatilization and/or
oxidation of the organic compounds in the waste (Table *fi). At the same
time, tests were conducted to determine the amounts of COD and BOD added to a
batch system by the dry bacterial culture alone (Table 10). A supplemental
air stripping/oxidation run was conducted near the end of the laboratory
test, examining the effect of volume on BOD/COD reductions. For convenience,
these data are shown on Table 9B4 Results of the foregoing test work will be
discussed later.
The supplier's recommended standard procedure was followed for
reactivating the dry bacterial culture. First, a measured amount (25 gms) of
bacteria/substrate material was added to three liters of distilled water and
heated to 38 C (1QQ F) and mixed for two hours. The batch was then aerated
94
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TABLE 9A
AIR STRIPPING/OXIDATION TESTS
VO
Ul
Aeration Time
(hrs)
Run
COD Rem.
Cmg/1)
0
1
2
4
24
48
72
5660
4228
2686
2412
1965
0
25.3
52.5
57.4
65.3
5504
2046
1450
1580
0
62.8
73.7
71.3
NOTE: Sample volume used was 1.5 liters.
Run #3
COD Rem. BOD Rem.
Cmg/1) % (mg/1) %
4761
3306
0
2637 44,6 1408 57.4
2030 57.4 960 71.0
1834 61.5 760 77.0
TABLE 9B
EFFECT OF VOLUME ON AIR STRIPPING/OXIDATION
Run #5- 22 gal. Volume
4280
Run #4
COD Rem. BOD Rem.
Cmg/1) % (mg/1) %
0
2340
0
3412 20.0 1980 15.4
2410 43.7
2222 48.1 1200 48.7
Aeration Only
Parameter
BOD
COD
Infl.
(mg/1)
1080
7560
Effl.
(mg/1)
780
5520
Rem,
27.8
27.0
Dry Bacteria
Effl.
Cmg/1)
740
5680
Rem.
SSL.
31.5
24.9
Run #6- 7 liter Volume
Aeration Only
Effl. Rem.
Cmg/1) (%)
780
3760
Dry Bacteria
Effl. Rem.
Qng/1) (*)
27.8
50.3
870
3840
18.4
49.2
NOTE: 24 hours aeration period on all units
-------
\0
TABLE 10
DRY BACTERIA-COD AND BOD DATA
BOD
Dry Bacteria Concentration Average
Aeration Time Adjusted Adjusted Adjusted Adjusted Adjusted
(hours) 0.75 gm/1 Value* 1.5 gm/1 Value* 2.25 gm/1 Value* 3.0 gm/1 Value* Value
24
48
72
44
60
86
Average BOD increase: 91
Aeration Time
(hours)
24
48
72
0.75 gm/1
80
102
245
59
80
115
mg/l/gm Dry
Adjusted
Value* 1.
107
136
327
92
112
106
61
75
71
290
274
140
128
121
62
386
268
314
128
89
104
94
91
88
Bacteria added
Dry
5 gm/1
165
177
280
COD
Bacteria Concentration
Adjusted Adjusted
Value* 2.25 gm/1 Value*
110
120
187
490
500
578
217
222
256
3.0 gm/1
122
725
895
Adjusted
Value*
240
242
298
Average
Adjusted
Value
169
180
267
Average COD increase; 205 mg/l/gm Dry Bacteria added
*Mathematically adjusted to a Dry Bacteria concentration of one mg/1.
-------
for 24 hours and aliquots were taken to produce various concentrations for
analysis. The test results (Table 10) indicated that BOD and COD material is
added by the dry bacterial culture. COD actually increases with aeration
over a period of hours while the B.OD concentration remains fairly constant.
These relationships are depicted on Figure 15 .
The zero hour time did not include the initial 24-hour aeration
period, therefore, the total aeration time from start of reactivation to the
end of the test was actually 96 hours. These tests indicated that the substrate
material will provide the bacteria with an adequate nutrient supply for at
least 72 hours, while also adding organic food (COD) material to the system.
Measurements of oxygen uptake rates on similar systems confirmed the continued
high biological activity over the same time period.
Dry bacterial cultures can also be used as an additive to an existing
biological system. Since poor results were being obtained from the continuous
system, this operation was discontinued and replaced by two new continuous
units, each containing biomass taken from a coke oven waste treatment plant.
Identical amounts of the synthetic waste were fed to each of the units.
Additionally, doses of the dry bacterial culture were introduced to one of
the units on a daily schedule prescribed by the supplier's instructions.
Gradually decreasing amounts of dry culture were added to this system until a
"maintenance" dosage level (2 grams per 6 liters) had been reached. This
dosage was continued for the duration of the testing period. Sludge from
these units was later used for additional batch tests. Results of the continuous
reactor testing will be discussed later in this report.
6.4.3.1 Batch Testing—
Three sets of batch tests were conducted, each set consisting of
four batch reactors aerated for 72 hours. Samples from the reactors were
taken every 24 hours and analyzed for COD, BOD and suspended and volatile
solids. Air flow to each system was stopped for one hour before sampling to
allow for solids settling. One reactor (Unit #1) in each series contained
wastewater only (no biologically active seed introduced) for the purpose of
comparing the effects of air stripping/oxidation of the waste to biological
oxidation. The contents of the other three reactors were prepared as follows:
Unit #2 - Wastewater plus coke oven sludge (from continuous Unit A)
97
-------
300
250
COD
u
U 200
<
CD
>-
Q
LL
o
2
150
O 100
BOD
50
24
48
TIME (hrs)
"T"
72
Figure i5. COD and BOD addition by dry bacteria.
98
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Unit #3 - Wastewater plus coke oven sludge with dry bacteria (from
continuous Unit B)
Unit #4 - Wastewater plus dry bacteria
Results of these batch tests are summarized in Table IX
6.4.3.2 Continuous Units—
Two continuous units were set up and operated for approximately
2 1/2 months. Both units (A and B) were seeded with a coke oven sludge, and
one unit (Unit B) also received a daily dose of dry bacteria. The systems
were contained in identical stainless steel reactor tanks each having a removable
baffle to aid in clarification of the effluent streams. The influent to both
systems was from a common tank and various concentrations of synthetic wastewater
were used as the feed material. Initially, the synthetic waste was diluted to
one tenth of the original strength and later changed to one quarter strength.
During the final three weeks of testing both units were fed full strength
synthetic wastewater.
Tables 12 and 13 show all data obtained from the continuous units.
Figure 16 plots the influent and effluent COD data for both units over the
entire testing period.
During the acclimation period (dilute waste feed), Unit B had
consistently lower COD removals for the first month. From the thirty-fifth to
the fiftieth day, both units operated very similarly. The full strength feed
was started and Unit B showed an obvious performance advantage over Unit A, at
least initially.
6.4.3.3 Control Assay Batch Test—
An 84-liter sample (22 gallons) previously treated for solids
removal was subjected to the original CA screening procedure for bio-oxidation.
This involved reactivation of dry bacteria and aeration with the waste for 24
hours. The dry bacterial culture concentration was 1.5 gm/liter. Results of
this test are summarized below:
Influent Effluent % Removal
COD BOD SS VSS pH COD BOD SS VSS pH COD BOD
6864 2200 117 71 7.9 3571 2110 362 271 7.6 48.0 4.1
Note: Except for pH, influent and effluent concentrations are expressed as
mg/1.
99
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TABLE 11
BIOLOGICAL OXIDATION
BATCH REACTOR RESULTS
Unit 13-Coke Oven Sludge
Unit »l-Air Stripping/Oxidation
Influent Effluent I Removal
BOD («g/l) 2823 1694 39.9
COD (•«/!) 4848 2698 44.3
Unit 12-Coke Oven
Influent
2520
4806
Effluent
1120
2078
Sludge
I Removal
55.5
56.7
+ Dry Bacteria
Inf luent
2630
4886
Effluent
1260
2368
Z Reaoval
52.1
51.5
Unit
Influent
2570
4860
14-Dry Bacteria
Effluent
1330
2162
I Removal
48.2
55.5
Aeration
(hra)
24
BOD («g/l) 2823 960 65.9
COD (ag/1) 4848 1980 59.1
BOD (*g/l) 2823 980 65.3
COD (mg/1) 4848 1879 61.2
2520
4806
2520
4806
930
1584
510
1404
63.1
67.0
79.7
70.7
2630
4886
2630
4886
660
1467
540
1275
74.9
70.0
79.4
73.9
2570
4860
2570
4860
1130
2043
840
1577
56.0
57.9
67.3
67.5
48
72
o
o
MOTES
Unit #1 contained 1.0 liter tapwater plua 4.5 lltera of wast*.
Unit #2 contained 1.0 liter of activated sludge fro* continuous Unit A plu* 4.5 liters of Mate.
Unit « contained 1.0 liter of activated aludga fro* continuous Unit B plua 4.5 lltera of waate.
Unit »l ctntliHad lio lltsr of reactivated dry bacteria (8.75 g»A> pi- 4.5 liter, of «a.te.
-------
TABLE 12
CONTINUOUS BIOSYSTEM TREATABILITY DATA
UNIT A
Effluent
Mixed Ligi
Date Temp SS VSS
(1978) (°C) (mg/1) (mg/1)
8/8
8/9
8/10
8/11
8/14
8/15
8/16
8/17
8/18
8/21
8/22
8/23
8/24
8/25
8/28
8/29
8/30
8/31
2492
2070
2020
1840
1304
1368
1192
1104
1124
1044
976
1012
998
1048
1064
972
776
2336
1950
1850
1716
1184
1312
1088
1052
1036
944
864
884
906
932
960
880
712
icr (.*}
DO
(mg/1)
7.6
7.6
8.0
7.6
7.4
7.4
7.4
7.6
7.4
8.1
8.1
7.4
7.8
7.8
8.0
8.0
8.0
DO UPT
(mjs/l/hr)
16
14
5
4
4
5
4
4
5
3
3
6
4
3.6
0
7
6
J.LKJU .LU
COD BOD5
(rog/1) (mg/D
58
490
375
307
82 30
442
130
770
575
890
822
750 442
1251
1138
1087
SS VSS COD BOD5 SS
(mg/1) (mg/1) (mg/1) (mg/1) (mg/1)
11
4
4
28
23
22
254
19
59
16
40
118
34
415
593
686
400
226
164
144
265
147
126
174
208
165
146
121
104
Z!>
415
360
84
51 4
56
102
60
10
14
24
22
34
136
116
VSS
(mg/1)
o c
25
390
334
82
(*) Coke oven activated sludge only
-------
o
to
Mixed Liquor (*)
TABLE 12(Con't)
CONTINUOUS BIOSYSTEM TREATABILITY DATA
UNIT A
Influent
Effluent
Date
(1978)
9/5
9/6
9/7
9/8
9/11
9/12
9/13
9/14
9/15
9/18
9/19
9/20
9/21
9/22
9/25
9/26
Temp
£cj.
16
21
24
20
21
26
21
21
25
25
SS
(me/1)
720
812
792
868
714
682
600
760
1176
772
656
460
vss
(mg/1)
720
784
766
737
702
594
508
612
764
604
576
340
DO
Qng/1)
8.6
8.2
7.2
9.5
8.0
8.6
8.8
8.0
7.6
8.8
8.4
7.6
7.4
DO UPT
(mg/l/hr)
6
6
7
2.4
7
6
4
5
8
2.4
5
14
14
COD
(mg/1)
834
831
913
716
542
519
748
901
1201
1031
1005
913
854
BOD5 SS VSS
(mg/1) Cmg/1) (mg/1)
306
294 30
246
206
176
104 56
COD
(mg/1)
97
97
90
73
98
85
81
53
46
75
53
55
BOD5 SS VSS
(mg/1) (mg/1) (mg/1)
3
0.6 58
0.6
0.6
2.2
42
6 24 10
(*) Coke oven activated sludge only
-------
TABLE 12(Con't)
CONTINUOUS BIOSYSTEM TREATABILITY DATA
UNIT A
Influent
Effluent
Date
(1978)
10/2
10/3
10/4
10/5
10/6
10/9
10/10
10/11
10/12
10/13
10/16
10/17
10/18
10/19
10/20
10/24
10/25
10/26
10/27
letup
£&
21
21
21
21
21
18
18
19
19
21
18
19
19
19
19
J.-J
SS
(mg/1)
1420
1244
1056
1108
1304
1448
1280
1244
1368
1000
_LACU JUJ.%1
vss
(mg/1)
1112
972
1788
892
1100
1236
1104
1052
1208
980
««•• v y
DO
(mg/1)
8.0
8.7
8.2
8.0
8.2
7.6
7.0
7.0
7.0
7.0
6.4
6.0
6.8
7.0
7.0
DO UPT
(mg/l/hr)
8
10
8
8
10
13
25
23
24
23
20
22
20
16
31
COD BOD5 SS VSS
(mg/1) (mg/1) (mg/1) (mg/1)
806
1149
1137 632
958
622
7209
6612
6481
6467
6218
6090
6012 3120
5967
5640
5158
4840
COD BOD5 SS VSS
(mg/1) (mg/1) (mg/1) (mg/1)
48
51
56 6
51
47
82
364
850
689
822
317
826
749
851 376
854
640
809
539
(*) Coke oven activated sludge only
-------
Mixed Liquor C*)
TABLE 13
CONTINUOUS BIOSYSTEM TREATABILITY DATA
UNIT B
Influent
Effluent
o
•e-
Date
(1978)
8/8
8/9
8/10
8/11
8/14
8/15
8/16
8/17
8/18
8/21
8/22
8/23
8/24
8/25
8/28
8/29
8/30
8/31
Temp SS
C°C) (mg/1)
180
2310
2450
3272
2460
2428
2072
1808
1844
1896
2616
2584
2288
3196
2708
VSS
(mg/1)
180
2200
2240
3272
1880
2380
1980
1796
1780
1840
2492
2460
2220
3068
2564
DO
(mg/D
7.4
5.2
5.2
4.6
4.6
5.0
5.5
5.6
6.4
5.4
2.2
3.0
6.2
7.0
5.4
DO UPT
(mg/l/hr)
18
46
46
38
30
27
16
18
12
40
COD
(mg/1)
490
375
307
82
442
130
770
575
890
822
750
1251
1138
1087
BOD5 SS VSS
(mg/1) (mg/1) (mg/1)
11
4
4
28
30 23
22
254
19
59
16
40
442
118
34
COD BOD5
(mg/1) (mg/1)
119.2
682
509
596
383 166
279
140
150
282
276
413
382 45
494
546
469
48
SS
(mg/1)
16
977
126
204
188
144
106
58
40
78
136
104
74
246
VSS
(mg/D
16
915
114
(*) Coke oven activated sludge plus dry bacterial culture
-------
TABLE 13(Con11)
CONTINUOUS BIOSYSTEM TREATABILITY DATA
UNIT B
Effluent
Date
(1978)
_^^ZB_B_W^I—
9/5
9/6
9/7
9/8
9/11
9/12
9/13
9/14
9/15
9/18
9/19
9/20
9/21
9/22
9/25
9/26
Temp
(°c)
18
22
25
21
22
27
22
22
25
26
M
SS
(mg/1)
1916
2014
2098
2036
2084
2128
2156
1756
1308
1320
1312
1392
ixed Liq
VSS
(mg/1)
1860
1908
2002
1884
1898
1912
1968
1544
912
1136
1148
1208
uor \*j
DO
(mg/1)
6.0
6.4
9.1
7.6
7.6
8.2
7.7
7.0
8.2
8.0
7.2
7.0
DO UPT
(mg/l/hr)
31
27
3
27
6
18
16
15
9.6
8.0
22
27
COD
(mg/1)
834
831
913
716
641
439
519
748
901
1201
1031
1005
913
R5A
O JH
A. 114. A UCU W
BODS SS VSS
(mg/1) (mg/1) (mg/1)
306
294 30 14
246
206
176
104 56 46
18 12
60 36
COD
(mg/1)
276
243
230
147
151
53
84
80
72
80
60
68
BOD SS VSS
(mg/1) (mg/1) (mg/D
17.4
12.6 86 82
11.4
1.8
6
3 56 48
90 74
66 30
(*) Coke oven activated sludge plus dry bacterial culture
-------
TABLE 13(_Conit)
CONTINUOUS BIOSYSTEM TREATABILITY DATA
UNIT B
Mixed Liquor C*)
Date
(1978)
10/2
10/3
10/4
10/5
10/6
10/9
10/10
10/11
10/12
10/13
10/16
10/17
10/18
10/19
10/20
10/24
10/25
10/26
10/27
Temp
££L
22
21
21
22
21
19
19
20
20
21
18
19
19
19
19
SS
(mg/1)
2040
2060
1340
2300
1964
2056
1968
2120
2204
2024
VSS
(mg/1)
1832
1780
2096
2040
1764
1876
1796
1908
2020
1864
DO
(mg/1)
7.8
8.0
7.8
7.8
8.0
7.4
6.8
6.8
6.8
6.4
7.6
7.4
7.4
7.2
7.2
DO UPT
(mg/l/hr)
14
12
13
12
18
17
38
39
39
49
34
34
32
38
39
Influent
COD BOD_ SS VSS
Qng/1) (mg/1) (mg/1) (mg/1)
806
1149
1137 632
958
622
7204
6612
6507
6481
6467
6218
6090
6012 3120
5967
5640
5158
4840
Effluent
COD BOD5 SS VSS
Qng/D (mg/1) (mg/D (mg/1)
52
51
48
43 6
51
78
256
488
313
284
127
362
327
343 420
338
448
682
523
(*) Coke oven activated sludge plus dry bacterial culture
-------
7000 —
eooo-
O
—J
5000-
o
o
o
INFLUENT -
BOTH UNITS
IOOO-
80
Figure 16. Continuous biological reactor results.
-------
6.4.4 Discussion of Results
It was anticipated at the outset that the bio-oxidation (activated
sludge) CA screening procedure would be fraught with many difficulties primarily
related (1) to the tight time frame of about one week initially set as being
reasonable for wastewater CAD, and (2) to the source of the biomass needed to
conduct the treatability screening tests. Generally speaking, acclimation of
a biomass to a specific waste stream requires several weeks. If the CAD time
schedule was to be maintained, the CA screening procedure would have to be
accomplished in several days. Substantial work was conducted during verifi-
cation testing which addressed these circumstances. Both wet and dry seed
approaches were studied.
Data collected during the early exploratory work with the dry
bacterial culture contained a number of anomalies. It was found (1) that
effluent COD concentrations were higher than effluent value, and (2) that the
COD concentration in the open feed container dropped rapidly on standing.
(The latter effect was very substanially reduced - but not totally eliminated -
by covering the feed vessel during the subsequent continuous biotesting
studies.)
Table 3J) shows that the organic foods/nutrients contained in the dry
bacterial culture mixture add an average of 91 mg/1 BOD and an average of 205
mg/1 COD per gram of culture. The COD value continues to increase with time
up to 72 hours of aeration.
The phenomenon of organic (BOD/COD) loss from the synthetic waste
mixture was addressed several times during verification testing through
studies involving aeration of different batches of synthetic waste under
varying test conditions. The data collected during these runs are presented
in Tables 9A, 9B, and 11.
The bulk of the results support the proposition that the losses
occur primarily through volatilization. However, there is some evidence that
chemical oxidation of the organics could also be involved. Whatever the
actual mechanisms might be, Table 9B and 11(Unit #1) show that the cumulative
effect of air stripping/oxidation is essentially reached after 48 hours of
aeration. Table 9B evaluates the effect of volume on BOD/COD reduction. A
stripping action is definitely indicated by the fact that the (smaller) units
with greater air to liquid ratios demonstrated higher reductions.
108
-------
Batch testing (Table 1} revealed no significant differences in BOD
and COD removals between the dry bacteria system (Unit //A) and the air stripping
system (Unit //I).
Both of the systems (Units #2 and #3) using coke oven activated
sludge as the bulk of the seed performed similarly, with better removals than
the stripping unit and the dry bacteria unit. In these batch tests, no
significant difference was observed between coke oven sludge alone (Unit #2)
and the system containing supplemental dry bacterial culture (Unit #3).
Average COD and BOD removals were calculated to compare the
effectiveness of the different units. After 24 hours, there was little
difference among any of the reactors in either BOD or COD removal, except for
Unit #1 which was somewhat lower. The units containing coke oven sludge (with
and without dry bacteria) began to show greater removals at 48 hours and this
trend continued for the 72 hour samples. The reactor containing dry bacteria
alone showed very little, if any, superiority over the air stripping/oxidation
reactor during the first day, and by the end of the test, the removals were
essentially equivalent. Unit #3 (coke oven sludge plus dry bacteria) had a
slightly higher COD removal rate than Unit #4 (coke oven sludge only), but the
difference was so small that it cannot be attributed to the dry bacteria. BOD
removals for these two units were identical.
Figure U6 shows influent and effluent COD data for both continuous
units during the entire test period. During the early part of the run, the
unit with dry bacteria addition (Unit B) showed higher effluent values.
Vendor instructions on the use of the dry bacterial culture as a supplemental
addition were followed in Unit B. The procedure specified a relatively high
initial dose followed by a decreasing dosage rate until a point where only a
maintenance dose is applied daily. Presumably, the effluent COD pattern
demonstrated by Unit B reflects the changing dosage rate of the bacterial
culture. (The effect' of culture dose on effluent COD has already been discussed)
When the dry bacteria addition reached the maintenance dosage level, COD
removals for this system (Unit B) reached a level equivalent to the coke oven
sludge system (Unit A)..
During the final three weeks of testing, both units were fed full
strength waste. The unit with the dry bacteria showed a much greater ability
to cope with the shock loading conditions encountered when the feed was
109
-------
abruptly changed to full strength. The companion unit was adversely affected
by the change in feed, although it gradually recovered over a three week
period when, because of time limitations, operation of all units was discontinued.
Results from verification testing of the bio-oxidation CA screening
procedure have produced much valuable information impacting on CAD wastewater
methodolgy. If the synthetic waste mixture used in the experimental work
closely simulates a real life coal conversion aqueous waste, then a substantial
portion of the organic removals usually attributed to oxidation by biological
organisms may well be physically stripped from the bio-reactor as an air
emission. Consequently, a simple aeration step in parallel with the biological
treatment step appears warranted to ascertain the extent to which organic
removals through stripping/oxidation is occurring.
Based on results developed with one commercial dry bacterial culture
mixture, the use of this type of dehydrated product as a biological seed does
not meet the needs of the CA screening procedure. A wet seed approach must be
adopted. Moreover, the wet seed must be acclimated for about 3 weeks to a
waste stream which is generally descriptive of the material that will eventually
be tested by the CA procedure.
Clearly, two choices present themselves. One is to disregard the
biological oxidation step entirely, which is not really reasonable, since this
approach will eliminate consideration of the effects of a major waste treatment
unit process. The second option is to begin biological acclimation (using a
locally available activated sludge as seed) three weeks in advance of the CA
wastewater screening study. During this time, the CA team could be generating
the air samples for IERL Level 1 analyses.
At the outset of verification biotesting, it was presumed that the
CA team would use COD analyses as the prime performance monitoring method,
backed up by an occasionalPreference BOD. In view of the experiences gained
during this test work, some doubt is now cast upon the validity of using COD
for these purposes. Changes»preduced by aeration in the oxidation state of
dissolved waste organics may Be clouding the dichromate chemistry with the
possibility of producing misleading data. It would appear that the CA team
should be equipped with a TOC analyzer for quantifying waste organic content
and for process monitoring purposes.
110
-------
6.5 ION EXCHANGE
6.5.1 Initial Concepts
Ion exchange resins are used to extract inorganic cations and
anions from liquids. It is expected that coal conversion wastewaters will
contain a large variety of impurities which have the potential for being
removed by some type of exchange resin. Ion exchange resins are made to
selectively remove certain ions from solution, and therefore, a single resin
cannot be expected to achieve high removals over the broad range of ions
possible in the wastewater. The driving force mechanisms encountered with
ion exchange resin operation are analogous to those for activated carbon, and
for this reason, batch treatment by resins is much less effective than a
continuous flow column system. A series of columns each containing a specific
resin would be the optimal configuration for removal of the largest amount of
impurities.
&• 5.2 Selected Alternative
After discussions with an ion exchange resins manufacturer, it was
decided to employ a three (.2-inch I.D.) glass column system set up in series.
The first column contained a strong-acid type resin, while the second column
was filled with a weak-acid resin. The final column contained a strong-base
resin. Prior experience by the manufacturer suggested that this combination
of resins would remove the majority of ions expected to be present in a
typical coal conversion wastewater. To minimize pumping requirements, a
single pump was to be used to introduce the sample into the first column, and
by proper positioning of the second and third columns, a continuous gravity
flow would be maintained.
6.5.3 Test Work
• • . • • — —. «
The ion exchange system was tested t:o evaluate its ability to
process the required aqueous sample within one work day. Excess solids in
the wastewater caused a flow rate problem in the .columns which was solved by
filtering the sample through the 75-micron cartridge and changing the resin
bed support media, A single pump was used to introduce the wastewater into
the first column, and gravity flow was employed through the second and third
columns. Constant adjustments to the column height and piping were necessary
to produce a continuous flow through all of the columns.
Ill
-------
CAD methodology specifies the use of ion exchange at two points in
the test sequence (Figure 13; after bio-oxidation; and after bio-oxidation
plus carbon adsorption. Reference analyses of a few selected metals were
made for these runs and the results are shown on Table !*•
6.5.4 Discussion of Results
The gravity flow concept is not acceptable since unequal pressure
drops through the columns, caused primarily by differences in resin particle
diameters, necessitated constant adjustments to the column heights to maintain
a continuous flow. It has been determined that the sample should be pumped
through one column at a time to eliminate this problem. Furthermore, to
reduce the possibility of plugging the resins with solids, a cartridge filter
should be placed In line before the first resin column.
The analytical data indicate that the ion exchange resins did
remove metals, although there was some performance variability from metal to
metal. The principal impact on CAD methodology is that an overall comparison
of the effluents from both runs show them to be reasonably similar. Therefore,
these results suggest that two ion exchange runs are not required for CAD
purposes. The ion exchange run after carbon adsorption Is the more appropriate
sit* selection in the test sequence.
In view of the increase in column sise (from 2-inch to 3-inch I.D.)
suggested for the carbon CA screening procedure, it is logical to also change
the ion exchange column sise to 3 inches. This alteration will gain
time during the ion exchange test run and will serve to standardise the
column sises for both screening procedures.
112
-------
TABLE 14
RESULTS OF ION EXCHANGE TESTING
Parameter
Iron as Fe, mg/1
Copper as Cu, mg/1
Cadmium as Cd, mg/1
Zinc as Zn, mg/1
Influent
0.7
0.18
0.06
0.36
Run //I
Effluent
1.5*
N.D.
0.05
0.22
Run #2
Effluent
0.7
0.034
0.05
0.15
Notes
Run //I was made on a sample after bio-oxidation plus carbon adsorption.
Run //2 was made on a sample after bio-oxidation only.
N.D. Indicates Not Detectable (less than 0.05 mmg/1).
*Possible contamination from equipment fittings.
113
-------
SECTION 7
CONCLUSIONS AND RECOMMENDATIONS - WASTEWATER
Laboratory verification of the CAD screening procedures revealed
several problems with the original wastewater methodologies. Minor equipment
changes were made to facilitate sample handling and a revision of the biological
oxidation procedure was necessary. Figure 17 shows the steps in the initial
CAD treatment sequence and includes verification testing results for those
processes examined.
Conclusions and recommendations developed from the study are:
Solids separation using an in-line cartridge filter presented
no difficulty and this approach will be adopted as originally
conceived.
Supplemental solids filtrations may be required, if precipitates
form in the wastewater sample, to prevent blinding of the
carbon and/or ion exchange resin beds.
Carbon adsorption should remain where proposed by the CAD
wastewater methodology, i.e., both before and after bio-
oxidation.
The carbon column diameter should be changed from the 2-inch
I.D. specified to 3 inches. A few minor column design modifi-
cations are also suggested.
Verification testing data strongly support the proposition
that a substantial portion of the BOD and COD removals demonstrated
during the bio-oxidation screening procedure can be attributed
to air stripping (volatilization). Therefore, the CAD waste-
water methodology should be modified to include an air stripping
step running in parallel with the specified bio-oxidation
screening procedure.
-------
COMPOSITE
BOD: 2260
COD: 6666
SS : 382
VSS: 226
pH : 8.0
FILTRATION
BOD: 2200
COD: 6860
SS : 117
VSS: 71
pll : 7.9
BIO-OXIDATION
BOD: 2110
COD: 3571
SS : 362
VSS: 271
pH : 7.6
CARBON-1
BOD:
COD:
SS :
VSS:
pH :
186
334
30
30
7.7
CARBON-2
BOD:
COD:
SS :
VSS:
pH :
197
347
73
48
7.6
ION EXCHANGE-1
BOD: 2100
COD: 3490
SS : 85
VSS: 42
Fe: 1.5
Cu: N. D.
Cd: 0.05
Zn: 0.22
ION EXCHANGE-2
BOD:
COD:
SS
VSS
PH
194
340
62
30
7.6
Fe: 0.7
Cu: 0.03
Cd: 0.05
Zn: 0.15
Figure
Results for synthetic waste sample.
115
-------
Insufficient benefit is derived from the use of a dry bacterial
culture during the bio-oxidation screening procedure to warrant
its adoption in the testing procedure.
To be effective, bio-oxidation screening must use an activated
sludge that has been acclimated to the wastewaters under
consideration for a period of 3 weeks prior to the formal
initiation of the CAD wastewater methodology. While acclimation
is under way, it is anticipated that the CAD team would be
pursuing the screening procedures specified by CAD air methodol-
ogies.
Based on experience derived during the verification testing,
the use of COD analyses as the monitoring method should be
replaced by TOC to provide a faster and more accurate analysis
of the organic composition of the samples.
The gravity flow concept through the ion exchange columns is
not acceptable as a CAD screening procedure. It is recommended
that the sample be pumped through the first column and the
effluent from each column be pumped through the next column in
series.
Evaluation of the effects of ion exchange should be studied
only after carbon adsorption and not before it. The wastewater
testing sequence should be altered accordingly.
The ion exchange column diameter should be standarized at 3
inches.
116
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SECTION 8
GASEOUS EMISSIONS SCREENING
S.I GAS BLEND COMPOSITION
A special gas blend was utilized during verification testing which
had the following composition:
Carbon Dioxide - 70%
Nitrogen - 29.55%
Hydrogen Sulfide - 2000 ppmv
Ethylene - 2500 ppmv
Two gas cylinders were required to obtain this blend, the first containing
the N2, H_S and C H,, and the second containing the CO-. Flow rates from
both cylinders were monitored by the use of rotameters and dry gas meters and
were adjusted to obtain the desired final gas composition (Figure 18) .
8.2 MODIFIED SAMPLING SYSTEM EVALUATION
8.2.1 Initial Concepts
In developing the CAD air methodologies, typical unit operations
needed to remove particulates and gases/vapors from air emissions were
evaluated. For various reasons, some of these operations had to be excluded
from consideration as CA screening procedures. Control technologies eventually
selected for the CAD methodology included; particulate removal, gas cooling
(condensation), carbon adsorption, and liquid scrubbing. Figure 19presents
the gaseous emission testing sequence.
The Source Assesment Sampling System (SASS) developed for IERL
Level 1 sampling made use of all these mechanisms for separation and collection
of gas stream contaminants, and therefore, initially seemed to be an ideal
system for use in CA screening procedures. It was thought that activated
carbon could replace XAD-2 in the same cartridge. However, subsequent calcu-
lations showed that the capacity of the standard XAD sorbent module used in
the SASS train would not be adequate for CA studies.
117
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SAMPLE POINTS
OPTIONAL SCRUBBER BYPASS
00
CO;
"z
H2S
C2H4
ROTOMETERS
MIXING
CHAMBER SCRUBBER
EXHAUST
TO
HOOD
GAS
CYLINDERS
GAS
METERS
CARBON
CANISTER
Figure 18. Scrubber evaluation apparatus.
-------
SOURCE
PARTICIPATE
REMOVAL
FOR LEVEL I
ASSAY
CONDENSATION
CARBON
ADSORPTION
2
SCRUBBING
CARBON
ADSORPTION
Figure ^. Gaseous emission test sequence.
119
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Several scrubbing media were investigated and sodium carbonate was
selected as the most promising. The capacity needed to remove acidic components
at expected concentrations was also calculated, and it was determined that
the standard SASS impinger assembly would not hold the required volume. The
existing condensation module in the SASS train was not expected to be a
problem, since sample flow rates and test duration would be similar to those
encountered in IERL Level 1 sampling.
8.2.2 Selected Alternative
In order to provide the extra capacity required for scrubbing, a
counter-current packed column scrubber with an 8-liter reservoir was designed.
A 4-inch I.D. by 5-foot glass column containing 3 feet of Raschig rings as
packing was used during verification testing.
Likewise, a larger canister to contain the activated carbon was
designed. A 4-inch I.D. by 3-foot glass column containing 10 Ibs. of activated
carbon (3-foot bed depth) was used for testing.
Figure 20 shows the configuration of the modified screening train as
assembled to evaluate scrubbing followed by activated carbon. Both control
technologies can be evaluated separately, if a process review indicates no
need to study both systems in series.
The solids removal module of the standard SASS has been incorporated
into the train. However, particulate removal technology will not be evaluated
during CA screening, because data for evaluating the effects of solids removal
technologies/control devices are obtained by the standard IERL Level 1 sampling
procedures, as amended by CAD methodologies. When sampling a gas stream with
a high particulate loading, this module will prevent particle build-up on the
activated carbon. The condenser module serves two purposes: for cooling of
the gas stream (to a carbon influent temperature of 55°C or less); and as a
separate unit process for removal of low-boiling organics.
8.2.3 Test Work
The standard SASS train presently requires two vane-type pumps
arranged in parallel in order to maintain a sample flow rate of 4 cubic feet
per minute through the sample collection portion of the train.
12C
-------
STANDARD
SASS TRAIN
CONDENSER
MODULE
S
PARTICIPATE
REMOVAL
>
ORIFICE DRY
GAS
METER
STANDARD
IMPNGER
MODULE
Figure 20. Combination scrubbing and carbon adsorption screening train.
-------
During a sampling run, particulates gradually build up on the
filter causing an increase in vacuum at the pumps. If this vacuum becomes
too great, the desired flow rate cannot be maintained and the system must be
shut down in order to replace the filter. Incorporating two additional
modules in the train (scrubber and carbon adsorption modules) increases the
total pressure drop across the system.
A SASS train was obtained from the manufacturer to quantify the
effects of the added components on the system. Testing was accomplished by
drawing room air through the SASS train alone, SASS train with carbon in-
line, and the complete system (SASS plus carbon canister and scrubber modules).
Vacuum hoses with an I.D. of one-quarter inch were used to connect the extra
modules to the SASS train. Tests were also performed to determine the pressure
drop across these lines. All vacuum readings were taken from the gauges
supplied with the pumps, and gas flow rate measurements were made using the
gas meter and timer which are part of the SASS train control unit. Before
the tests were conducted, a filter was placed in the filter holder, three of
the impingers were each filled with 750 milliters of tap water and the fourth
impinger was charged with silica gel. XAD-2 resin was placed in the sorbent
cartridge assembly. Results of these tests are presented in Table 15.
Preliminary calculations indicated that 8 liters of scrubbing
o
solution (1-Normal sodium carbonate) would be required to scrub 1000 ft of
sample with an H?S concentration of approximately 2000 ppmv. Additional
calculations indicated that five pounds of activated carbon would be adequate
for removal of organic compounds expected in a waste gas stream. To verify
these calculations, the special gas blend was used.
The gases were first introduced into a mixing chamber where initial
samples were taken to determine both H.S and total hydrocarbon concentrations.
From the mixing chamber, the gases then flowed through the scrubber unit and
the carbon canister. Several test runs were made on each unit separately,
and one run was conducted to determine H_S and hydrocarbon removals with both
122
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TABLE 15
SCREENING TRAIN PRESSURE DROP TESTING
Flow Rate Vacuum Flow Rate Vacuum
(cfm) (in. Hg) (cfm) (in. Hg)
Standard SASS 4.0 8.5 3.0 6.0
Scrubber and Connecting Lines 4.0 8.5 3.0 5.0
Connecting Lines (Only) 4.0 6.5 3.0 4.0
Scrubber 4.0 2.0 3.0 1.0
Carbon Columns and Connecting Lines 4.0 5.0 3.0 4.0
Connecting Lines (Only) 4.0 4.5 3.0 3.5
Carbon Columns 4.0 0.5 3.0 0.5
TOTAL SYSTEM 4.0 18.5 3.0 9.0
(Standard SASS with both scrubber 3.7 15.0
and carbon columns on-line)
123
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units in series. Total hydrocarbons were measured by taking a 100 ml gas
sample and injecting directly into a gas chromatograph equipped with a flame
ionization detector. Methane was used as the standarizatlon gas, and therefore,
the results are presented as total hydrocarbons expressed as methane. Hydrogen
sulfide levels were measured by drawing a sample of the gas directly through
H?S detector tubes. Results of the testing are presented in Tables 16-19.
8.2.4 Discussion of Results
The particulate collection system used in the standard SASS train
consist of 3 cyclone separators in series followed by a fiberglass filter.
The cyclones have nominal cut-points of 10U, 3p and ly, respectively. The
fiberglass filter is used to collect particles smaller than ly. Proper
operation of the cyclones is dependent on the sample gas flow rate through
the system, with 4 cfm being the optimum design flow rate. At this rate, a
typical test run collecting 1000 cubic feet of sample has an approximate
duration of 4.5 hours. Depending on particulate loading in the gas stream,
it may become impossible to maintain a 4 cfm flow rate through the modified
SASS train (scrubber and carbon modules in line); however, the only problem
this presents is an extended sampling period. For the purposes of the CA
screening procedures, it is not absolutely necessary to maintain the 4 cfm
flow rate.
The laboratory testing was performed using 1/4-inch I.D., heavy-
wall vacuum tubing for connection of the screening modules to the SASS train.
The sample flow piping in the standard train is I/2-inch I.D., and it is
recommended that this size tubing be used for the design of the actual screening
train to eliminate the pressure drop caused by the smaller diameter tubing.
The modular construction of the entire screening train makes it a simple
matter to add or delete components or rearrange the sequence of any of the
units, depending on prior knowledge of the gas stream constituents and/or the
desired application of the train at a particular source.
From SASS train work experiences reported by others, it is estimated
that three men will be able to perform a complete screening test on a single
source in a time period of two days. Considering the possibility of encountering
multiple sources in a plant, it becomes obvious why a plan of selective
sampling based on process knowledge is of paramount importance in this program,
if total field time is to be controlled within acceptable limits.
124
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TABLE: *6
Run #1 - SCRUBBER EVALUATION
Inlet Concentration
Outlet Concentration
% Removal
(minutes)
0
30
60
90
95
100
115
130
145
to
at
(cubic feet)
0
29.2
78.5
116.3
124.9
131.3
144.7
166.8
195.0
H2S (ppm)
1800
1960
2000
2000
1800
1150
1900
2000
2000
Total Hydrocarbon*
1301
-
1344
-
939
-
683
-
—
H2S (ppm)
4
3
3
100
200
360
600
900
1150
Total Hydrocarbon*
1770
-
2560
-
1088
-
704
-
—
H2S
99.7
99.8
99.8
95.0
88.9
68.6
68.4
55.0
42.5
Total Hydrocarbon
_
-
-
-
-
-
-
-
—
* ppm as methane
-------
TABLE 17
RUN #2 - SCRUBBER EVALUATION
to
O>
Time
(minutes)
0
10
20
35
50
65
80
Gas Volume
(cubic feet)
-
11.4
21.5
39.4
55.6
73.1
93.1
Inlet Concentration
H2S (ppm)
2800
2400
2200
2200
2200
2400
2200
Outlet Concentration
H2S (ppm)
10
50
45
100
210
400
810
% Removal
H2S
99.6
97.9
97.9
95.4
90.4
81.8
63.1
-------
TABLE 18
RUN #1 CARBON ADSORPTION
Time
(minutes)
0
15
25
40
45
Gas Volume
(cubic feet)
—
26.5
53.3
63.8
71.1
Inlet
H2S (ppm)
2100
2100
2400
2400
2350
Concentration
Total Hydrocarbon*
1148
1193
-
1418
_
Outlet
H2S (ppm)
2
2
200
500
1000
Concentration
Total Hydrocarbon*
901
1190
-
1418
_
H2S
99.9
99.9
91.6
79.1
57.4
% Removal
Total Hydrocarbon
21.5
-
-
-
_
* ppm as methane
-------
TABLE 19
RUN #1 - SCRUBBING FOLLOWED BY CARBON ADSORPTION
00
Time
(minutes)
0
25
60
90
105
120
150
Gas Volume
(cubic feet)
_
37.2
94.6
143.2
167.1
192.6
240.6
Inlet
H2S (ppm)
2400
2400
2100
2200
2400
2200
2400
Concentration
Total Hydrocarbon*
1060
1250
-
-
•
-
—
Outlet
H2S (ppm)
5
10
40
100
240
500
1250
Concentration
Total Hydrocarbon*
1000
1275
-
-
-
-
-
H2S
99.8
99.6
98.1
95.4
90.0
77.2
47.9
% Removal
Total Hydrocarbon
5.7
-
-
-
-
-
-
* (ppm as methane)
-------
The results of pilot scrubber testing (see Tables 16 and 17) indicate
that 8 liters of sodium carbonate scrubbing solution will not be adequate
when drawing a 1000 cubic foot sample which has an acid gas concentration
(H S, SO etc.) of 2000 ppmv or greater. It was observed during the test
period that the scrubber solution became totally ineffective at a pH of 10.0
or less. It is recommended that the solution concentration be increased to
2-Normal, and that the total volume available in the reservoir be increased
to 16 liters. As an extra precaution, a pH meter should be used to monitor
the condition of the scrubbing medium. If it is necessary to halt the run
for a filter change at any time during the test, the scrubbing solution
should also be replaced at that time.
Removal of ethylene from the test gas stream by activated carbon
was very poor (Tables 18 and 19). It is not known whether this was due to an
inherently low adsorption capacity for this compound onto the test carbon, or
if the large quantity of carbon dioxide present in the stream resulted in
flushing the ethylene through the system. Organics with higher molecular
weights stand a much better chance of being adsorbed on the carbon, and for
this reason, it is recommended that the carbon module be retained in the
screening program. It is not practical to substantially increase the amount
of carbon used in the screening train because (1) the train already consists
of many modules which are large enough to present problems when the sample
location is difficult to reach, and (2) space at the sample point will be
restricted in most cases. The CA screening procedure for carbon during Level
1 may be somewhat limited, but will nevertheless be indicative of the potential
of the process for removing organic contaminants, and serve as a guide for
future studies.
In order to obtain meaningful results from the CA tests, it is
imperative that each source to be evaluated be sampled according to the Level
1 IERL methods in addition to the screening sampling. Ideally, both tests
will be run simultaneously. If this is not possible, process data for each
source must be evaluated to determine the constancy of operation and judgement
must be used to assess the reliability of comparing data from two non-simultaneous
test runs.
129
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SECTION 9
CONCLUSIONS AND RECOMMENDATIONS - GASEOUS EMISSIONS
Laboratory verification tests indicated that the use of a SASS
train is feasible for CA screening procedures when the following modifications
have been made:
The organic adsorbent module and impingers indigenous to the
SASS equipment train are not of suitable size for use in CA
screening procedures. The screening procedures using scrubbing
and carbon adsorption specified by CAD air methodologies
should be adopted.
Special supplemental scrubber and adsorber modules will be
required for gaseous CA screening procedures to be used in
conjunction with the SASS equipment. Typical supplemental
modules for these unit operations were tested in the laboratory.
For CA screening procedures, it is acceptable to reduce the
sample gas flow rate to 3 cfm.
pH of the scrubber liquid should be monitored and replaced
when it falls below 10.0 standard pH units.
130
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REFERENCES
1. Standard Methods for thr examination t>f Water and Wastcwater.
14th Edition. 1975.
2. Hamersma, J.W., Regnolds, S»L., and Maddalone, R.F. lERL-Procedures
Manual: Level 1 Environmental Assessment. EPA-600/2-76-160A. June 1976.
3. Federal Register. Standards of Performance for New Stationary Sources.
Volume 36. No. 247, December 23, 1971.
4. Blake, D. Operating and Service Manual - Source Assessment Sampling
System. Aerotherm Report. UM-77-80, March 1977.
Singer, P.C., et al., "Assessment of Coal Conversion Wastewater:
Characterization and Preliminary Biotreatability," EPA 600/7/78-181, pp. 95,
6. Beychok, Milton R., "Coal Gasification and the Phenosolvan Process,"
presented at the 168th National Meeting of the American Chemical Society-
Division of Fuel Chemistry, Atlantic City, N.J. September 1974,
Volume 19 No. 5, pp. 85-93.
131
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TECHNICAL REPORT DATA
(Please read JnUructions on the reverse before completing]
1 REPORT NO. 2.
EPA-600/7-80-002
4. TITLE ANDSUBTITLE
Control Assay Development: Methodology and
Laboratory Verification
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
January 1980
6. PERFORMING ORGANIZATION CODE-
7. AUTHORIS)
W. F. Longaker, S.M. Hossain, and A. B. Cherry
8. PERFORMING ORGANIZATION REPORT NO.
9 PERFORMING ORGANIZATION NAME AND ADDRESS
Catalytic, Inc.
1500 Market Street
Philadelphia, Pennsylvania 19102
1O. PROGRAM ELEMENT NO.
EHE623A
11. CONTRACT/GRANT NO.
68-02-2167, Tasks 9 and 12
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
inal;
PERIO
OVERED
14. SPONSORING AGENCY CODE
EPA/600/13
IB SUPPLEMENTARY NOTES J.ERL-RTP project officer is Robert A. McAllister, Mail Drop 61,
919/541-2160.
16 ABSTRACT The report des cribes Control Assay Development (CAD), a data acquisition
program designed to evaluate the potential applicability of various treatment pro-
cesses for the control of solid, liquid, and gaseous emissions from coal conversion
plants. The CAD program described could be used to provide data for evaluating
selected treatment technologies for coal conversion wastewaters. Detailed descrip-
tions of all CAD screening procedures and equipment required for outfitting a mobile
laboratory are presented. Laboratory tests were conducted to assess the adequacy
of the proposed designs and operating procedures, and to verify the use of a dry
bacterial culture for biological oxidation studies. A number of design modifications
were recommended, based on the laboratory tests. Insufficient benefit is derived
from the use of a dry bacterial culture during the bio-oxidation screening procedure
to warrant its adoption in the testing procedure.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Assaying
Coal
Coal Gasification
Waste Water
Biology
Oxidation
Pollution Control
Stationary Sources
Control Assay Develop-
ment
Biological Oxidation
Coal Conversion
13B
14B
08G,21D
13H
06C
07B,07C
13. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NOJDF PAGES
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
132
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