WATER POLLUTION CONTROL RESEARCH SERIES
12020 EID 03/71
Preliminary Investigational
Requirements-
Petrochemical and Refinery
Waste Treatment Facilities
ENVIRONMENTAL PROTECTION AGENCY WATER QUALITY OFFICE
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Series describes the
results and progress in the control and abatement of pollution
in our Nation's waters. They provide a central source of
information on the research, development, and demonstration
activities in the Water Quality Office, Environmental Protection
Agency, through inhouse research and grants and contracts with
Federal, State, and local agencies, research institutions, and
industrial organizations.
Inquiries pertaining to Water Pollution Control Research Reports
should be directed to the Head, Project Reports System, Office
of Research and Development, Water Quality Office, Environmental
Protection Agency, Room 1108, Washington, D.C. 20242.
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"PRELIMINARY INVESTIGATIONAL REQUIREMENTS -
PETROCHEMICAL AND REFINERY WASTE TREATMENT FACILITIES"
prepared by
ENGINEERING-SCIENCE, INC./TEXAS
3109 N. Interregional
Austin, Texas 78722
for the
WATER QUALITY OFFICE
ENVIRONMENTAL PROTECTION AGENCY
Project #12020 EID
Contract #14-12-588
March 1971
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.50
Stock Number 5501-0089
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EPA Review Notice
This report has been reviewed by the
Environmental Protection Agency and
approved for publication. Approval does
not signify that the contents necessarily
reflect the views and policies of the
Environmental Protection Agency, nor does
mention of trade names or commercial products
constitute endorsement or recommendation for
use.
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ACKNOWLEDGMENTS
Appreciation is hereby expressed to the many contributors, reviewers,
and editors who helped compile this report and insure its completeness and
accuracy.
This profile was sponsored by the Environmental Protection Agency.
The preliminary draft was reviewed on behalf of the Environmental Pro-
tection Agency by Mr. J. A. Horn, Mr. L. D. Lively, Mr. L. H. Myers,
and Mr. George Key. Their comments and suggestions are duly acknowledged.
Particular appreciation is expressed to Dr. Earnest F. Gloyna,
Consultant, who helped review the literature.
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ABSTRACT
The objectives of this report include the compilation, interpretation,
and presentation of the pertinent aspects which constitute a preliminary
wastewater treatability study for the refining and pretrochemical
industries. The preliminary investigation relative to the successful
treatment of petrochemical and refinery wastewaters should include those
factors essential in the proper development of design criteria for
pollution abatement and control facilities.
The wastewater survey is the basis from which a treatability study can
be developed, and necessarily includes locating, analyzing, and properly
interpreting the nature of pollutional sources within a petrochemical or
refinery complex. This includes normal process and utility effluent,
contaminated storm runoff, ballast water discharge, and other related
sources of wastewater. Each of these wastewaters must be properly
characterized with respect to their organic and inorganic constituents.
This characterization schedule is designed to best determine the impact
of the particular waste stream on the treatment facility and the
receiving body of water. In-plant control of wastewaters is an integral
part of any survey as the elimination or sequestering of pollution at
the source is often the most economical approach toward resolving the
problem.
The treatability study; whether it involves chemical, biological, or
physical treatment, must necessarily be programmed to yield definitive
information concerning pollutional removal rates, anticipated levels
of residual or non-removable constituents, and treatment process re-
quirements. Translating bench or pilot scale data to prototype design
then must incorporate proper scale-up factors.
The overall project of evaluating the treatability of a wastewater is
predicated on the assimilation of sufficient information from which
the optimal selection of treatment processes can be made. Given man-
power and cost constraints in view of this objective, the scope 'of
any treatability study must be carefully planned and properly imple-
mented .
This report was submitted in fulfillment of Contract No. 14-12-588
between the Federal Water Quality Administration and Engineering-
Science, Inc.
Key Words: Treatability, wastewater characterization, organic and
inorganic constituents, bench scale or pilot scale
studies, scale-up, correlation of organic parameters,
screening procedures.
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GLOSSARY OF TEEMS
Adsorption The adherence of dissolved, colloidal, or finely divided
solids on the surfaces of solid bodies with which they are brought
into contact.
Aeration The bringing about of intimate contact between air and a
liquid by one of the following methods: Spraying the liquid in
the air; bubbling air through the liquid; or by agitation of the
liquid to promote surface absorption of air.
Alkalinity A term used to represent the content of carbonates, bi-
carbonates, hydroxides, and occasionally borates, silicates, and
phosphates in water. It is expressed as parts per million of
calcium carbonate.
Bacteria, Aerobic Bacteria which require free (elementary) oxygen
for their growth.
Bacteria, Anaerobic Bacteria which grow in the absence of free oxygen
and derive oxygen from breaking down complex substances.
Basin, equalization A basin employed to even out irregularities in
flow and constituent concentration.
Biochemical Oxygen Demand (BOD) A utilization of organic materials
by bacteria expressed in terms of oxygen demand.
Chemical Oxygen Demand (COD) A measure of the oxidation of organics
using potassium dichromate as the oxidant.
Carbon, Activated Carbon particles usually obtained by carbonization
of cellulosic material in the absence of air and possessing a high
adsorptive capacity.
Coagulation The agglomeration of colloidal or finely divided suspended
matter by the addition to the liquid of an appropriate chemical co-
agulant, by biological processes, or by other means.
Flocculation The formation of small gelatinous masses in a liquid by
the addition of coagulants or through biochemical processes or by
agglomeration.
Flotation A method of raising suspended matter to the surface of the
liquid in a tank as scum by aeration, by the evolution of gas,
chemicals, electrolysis, heat, or bacterial decomposition and
the subsequent removal of the scum by skimming.
Lagoon, Sludge A relatively shallow basin, or natural depression,
used for the storage or digestion of sludge, and sometimes for its
ultimate detention or dewatering.
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Liquor Water, sewage, and industrial wastes, or any combination
of the three.
Liquor, Mixed A mixture of activated sludge and sewage in the aeration
tank undergoing activated sludge treatment.
Nitrification The oxidation of organic nitrogen into nitrates through
biochemical action.
Outfall The point or location where sewage or drainage discharges from
a sewer, drain, or conduit.
Oxygen, Dissolved Usually designated as D.O. The oxygen dissolved in
sewage water or other liquid usually expressed in parts per million
or percent of saturation.
Period,Aeration The theoretical time, usually expressed in hours, that
the mixed liquor is subjected to aeration in an aeration tank under-
going activated sludge treatment; is equal to (a) the volume of the
tank divided by (b) the volumetric rate of flow of the sewage and
return sludge.
Sedimentation The process of subsidence and depositon of suspended
matter carried by water, sewage, or other liquids, by gravity. It
is usually accomplished by reducing the velocity of the liquid below
the point where it can transport the suspended material.
Sedimentation, Final Settling of partly settled flocculated or oxidized
sewage in a final tank.
Seeding, Sludge The inoculation of undigested sewage solids with sludge
that has undergone decomposition, for the purpose of introducing
favorable organisms, thereby accelerating the initial stages of
digestion.
Sludge, Activated Sludge floe produced in raw or settled sewage by the
growth of zoogleal bacteria and other organisms in the presence of
dissolved oxygen, and accumulated in sufficient concentration by
returning floe previously formed.
Sludge, Conditioning Treatment of liquid sludge preliminary to de-
watering, and to facilitate dewatering and drainability, usually
by the addition of chemicals.
Sludge, Dewatering The process of removing a part of the water in sludge
by any method, such as draining, evaporation, pressing, centrifuging,
exhausting, passing between rollers, or acid flotation, with or without
heat. It involves reducing from a liquid to a spadable condition
rather than merely changing the density of the liquid (concentration)
on the one hand or drying (as in a kiln) on the other.
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Sludge, Digested Sludge digested under anaerobic conditions until the
volatile content has been reduced, usually around 50 percent.
Sludge, Primary Sludge obtained from a primary settling tank.
Sludge, Process A biological sewage treatment process in which a
mixture of sewage and activated sludge is agitated and aerated.
The activated sludge is subsequently separated from the treated
sewage (mixed liquor) by sedimentation, and wasted or returned
to the process as needed. The treated sewage overflows the weir
of the settling tank in which separation from the sludge takes
place.
Solids, Suspended (1) The quantity of material deposited when a
quantity of water, sewage, or other liquid is filtered through an
asbestos mat in a Gooch crucible. (2) The solids that either float
on the surface of, or are in suspension, in water, sewage, or other
liquids; and which are largely removable by laboratory filtering.
Solids, Volatile The quantity of solids in water, sewage, or other
liquid lost on ignition of the total solids.
Tank, Aeration A tank in which sludge, sewage, or other liquid is
aerated.
Tank, Final Settling A tank through which the effluent from a
trickling filter, or aeration or contact aeration tank flows
for the purpose of removing the settleable solids.
Tank, Flocculating A tank used for the formation of floe by the
agitation of liquids.
Tank, Mixing A tank or channel so designed so as to provide a
thorough mixing of chemicals introduced into liquids.
Tank, Surge A water tank employed to absorb irregularities in flow.
Total Organic Carbon (TOG) Concentration of organic material as
expressed in terms of total organic carbon.
Total Oxygen Demand (TOD) Oxygen demand as measured using automated
total combustion techniques.
Treatment, Primary removal of settleable solids.
Treatment, Secondary Treatment, by biological methods, generally
activated sludge, to remove BOD from a waste.
Treatment, Tertiary Treatment, generally by activated carbon
sorption, to remove residual COD after secondary treatment.
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TABLE OF CONTENTS
ACKNOWLEDGEMENTS
Page
i
ABSTRACT i:L
GLOSSARY OF TERMS ii±
TABLE OF CONTENTS vi
LIST OF TABLES vii
LIST OF FIGURES ix
CONCLUSIONS xii
RECOMMENDATIONS xv
CHAPTER 1 - INTRODUCTION 1
CHAPTER 2 - THE WASTEWATER SURVEY 8
CHAPTER 3 - WASTEWATER CHARACTERIZATION 39
CHAPTER 4 - IN-PLANT CONSIDERATIONS 64
CHAPTER 5 - THE TREATABILITY STUDY 75
CHAPTER 6 - COMPARISON OF LABORATORY AND
PROTOTYPE TREATABILITY INFORMATION 146
CHAPTER 7 - MANPOWER AND TIME REQUIREMENTS 155
CHAPTER 8 - COSTS OF WASTEWATER TREATABILITY STUDIES 164
LIST OF REFERENCES
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LIST OF TABLES
Table Title Page
1 SAMPLING STATION DESCRIPTION 15
2 ANALYSES COMPLETED IN A WASTEWATER
CHARACTERIZATION STUDY OF A PETRO-
CHEMICAL INDUSTRY 17
3 SAMPLING AND ANALYSIS SCHEDULE -
INFLUENT AND EFFLUENT STATIONS 19
4 SAMPLING AND ANALYSIS SCHEDULE -
PROFILES WITHIN AN AERATED LAGOON
BASIN 20
5 WASTEWATER CHARACTERISTICS FROM A
SMALL PETROCHEMICAL INDUSTRY 22
6 STORM OCCURRENCE AND QUANTITY OF
RUNOFF FROM A PETROCHEMICAL
INDUSTRIAL AREA 26
7 SCHEDULE FOR OBSERVATION, SAMPLE
COLLECTION, MEASUREMENT, AND
ANALYSIS 31
8 RECOMMENDED STORAGE PROCEDURE 33
9 SAMPLE PRESERVATION 34
10 TOTAL OXYGEN DEMAND REACTIONS 47
11 CHEMICAL WASTE CHARACTERISTICS 49
12 EVALUATION OF COD AND BOD WITH RESPECT
TO THEORETICAL OXYGEN DEMAND - TEST
ORGANIC CHEMICALS 50
13 INDUSTRIAL WASTE OXYGEN DEMAND AND
ORGANIC CARBON 52
14 COD/TOG RELATIONSHIPS 53
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Table Title Pag£
15 COD/TOD RATIOS FOR UNTREATED
INDUSTRIAL WASTEWATERS 54
16 STATISTICAL ANALYSIS 57
17 CATEGORIZATION OF UNIT PROCESSES 76
18 PRE OR PRIMARY TREATMENT REQUIREMENTS 81
19 TREATABILITY PROBLEMS LEADING TO SCALE-
UP FACTOR CONSIDERATIONS 147
20 COMPARISON OF AVERAGE ACTIVATED SLUDGE
OPERATIONAL VALUES FOR BENCH SCALE
AND PROTOTYPE UNITS 149
21 SUMMARY, PERSONNEL REQUIREMENTS FOR A
24-HOUR WORKDAY 157
22 TASKS FUNCTIONS AND EDUCATIONAL EXPERIENCE
NECESSARY FOR EFFECTIVE OPERATION OF A
POLLUTION CONTROL PROGRAM 158
23 MINIMUM TIME REQUIREMENTS FOR COMPLETION
OF ALL TASKS IN TREATABILITY STUDIES 162
24 COSTS OF CHEMICAL ANALYSIS OF WASTEWATERS 166
25 LABOR COSTS INVOLVED IN TREATABILITY STUDIES 168
26 GENERALIZED COSTS OF TREATABILITY STUDIES 169
27 FRACTION OF COST PAID TO PERSONNEL IN
TREATABILITY STUDIES 169
28 COSTS OF COMPLETED TREATABILITY STUDIES 170
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LIST OF FIGURES
Figure Title Page
1 SEQUENTIAL STEPS REQUIRED TO MINIMIZE
AND ELIMINATE THE POLLUTIONAL EFFECT
OF WASTEWATERS FROM REFINERY AND
PETROCHEMICAL INDUSTRIES 7
2 SEWER SEGREGATION AND OIL REMOVAL 10
3 IN-PLANT PRETREATMENT OF HIGH CON-
TAMINATION WASTE STREAMS 11
4 EXAMPLE OF WASTEWATER SAMPLING STATION
LOCATION IN A COMPLEX PETROCHEMICAL
INDUSTRY 14
5 FLOW VARIATIONS RESULTING FROM BATCH
UNIT PROCESS OPERATION IN A PETRO-
CHEMICAL INDUSTRY 24
6 OBSERVED FLOW VARIATIONS FOR PROCESS
EFFLUENT SHOWN IN FIGURE 5 - AFTER
EQUALIZATION BASINS 25
7 ORGANIC CONTAMINATION OF RUNOFF 27
8 CHARACTERIZATION OF LIQUID WASTEWATER 40
9 RELATIONSHIP BETWEEN OXYGEN AND CARBON
PARAMETERS 41
10 BIOCHEMICAL OXYGEN DEMAND 44
11 FLOW DIAGRAM OF MODIFIED CARBON ANALYZER 46
12 CORRELATION OF ORGANIC PARAMETERS (MEAN
VALUES) 56
13 EFFECT OF BOD -COD RATIO ON TREATABILITY 59
14 EFFECT OF BOD -COD, TOC RATIO ON
TREATABILITY 60
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Figure Title
15 TOTAL WATER USE IN REFINERIES 65
16 MINIMUM REFINERY CAPACITIES FOR ECONOMIC
CHEMICAL MANUFACTURE VERSUS CAPACITY
OF U. S. REFINERIES 69
17 AVERAGE DAILY EFFLUENT BOD LOADING. SEADRIFT
PLANT UNION CARBIDE, INC. 73
18 WASTEWATER TREATMENT FLOW DIAGRAM 78
19 BENCH SCALE LIMESTONE COLUMN 84
20 LABORATORY SETTLING COLUMN 86
21 BENCH SCALE FLOTATION UNIT 88
22 BATCH REACTOR 92
23 SCREENING PROCEDURES USING BATCH BIOLOGICAL
REACTORS 93
24 DILUTION EFFECT ON RESPIRATION RATES 94
25 CONTINUOUS FLOW LABORATORY REACTOR 96
26 BENCH SCALE TRICKLING FILTER 99
27 WASTE STABILIZATION POND MODELS 102
28 LABORATORY SCALE OZONE TREATMENT 104
29 BENCH SCALE GAS STRIPPING TOWER 110
30 LABORATORY ELECTRODIALYSIS UNIT 115
31 LABORATORY ION EXCHANGE COLUMNS 117
32 LABORATORY TUBULAR REVERSE OSMOSIS UNIT 120
33 LABORATORY SAND FILTER 124
34 ANALYSIS FOR SLUDGE CHARACTERIZATION 126
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Figure Title Page
35 LABORATORY BATCH-FED DIGESTOR 129
36 CONTINUOUS-FEED DIGESTOR 130
37 EFFECT OF SLUDGE DEPTH IN THICKENER
AS A DESIGN PARAMETER 152
38 SEQUENCE OF EVENTS IN A TREATABILITY
STUDY 160
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CONCLUSIONS
The following conclusions are based on a review of treata-
bility study and preliminary investigative requirements.
1. The trend of recent refinery and petrochemical complex
construction has been toward the emphasis of oil recovery from
oily waste streams, separation of high and low organic wastewaters,
in-plant control, and water reuse. Treatability studies and pre-
liminary engineering considerations should be directed toward the
continuance and enhancement of this philosophy.
2. The characteristics of wastewaters discharged from
refinery and petrochemical complexes depend on the age of the
facility, the nature and source of the crudes processed, the
design and type of production facilities, the cooling water re-
quirements, and the degree of in-plant housekeeping and control
practiced. Generally, wastewaters from refineries tend to have
more uniform characteristics than the more complex and diverse
liquid wastes discharged from petrochemical facilities.
3. Wastewater surveys should be designed so as to classify
wastewater sources with respect to oily and non-oily substances,
inorganic and organic contaminants, high TDS and low TDS waters,
and sanitary discharges. A survey, so oriented, assures a more
practical engineering solution.
4. Sampling points and frequencies should be consistent with
the "pollution potential" of the station in question. Batch process
operations normally require more frequent sampling than do con-
tinuous process operations. Areas from which waters containing
high concentrations of pollutants are discharged should be sampled
frequently enough to provide statistically reliable information.
5. The survey should include flow measurements at critical
points not only to serve as a basis for compositing samples but
also for establishing critical base flow patterns within the com-
plex. Moreover, such information is necessary for calculating
total pollutional loads discharged.
6. The quality and quantity of storm runoff should be ob-
tained for major storms which occur during the wastewater survey
period. If this is not possible, runoff information should be
synthesized as accurately as possible.
7. Wastewater surveys should include estimates of contami-
nants emanating from sources other than storm or process discharges,
such as ballast handling areas, truck dump areas, sources of pipe-
line leaks, tank farms, and areas from which accidental spills com-
monly occur.
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8. Analyses should be performed as close to the source as
possible. If this cannot be done, samples collected during the
survey phase should be carefully preserved until the necessary
analyses can be performed. Refrigeration without freezing,
freezing, and acidification are the methods most commonly used.
Selected confirmatory analyses should be performed to insure
that the integrity of the sample has been maintained between
the time of sampling and testing.
9. An analytical program should be designed in order to
best describe critical pollutants. Inorganic analyses are
rather well defined, although organic analyses often are more
difficult to interpret. The BOD test is subject to many limi-
tations, particularly when estimating the organic content of
refinery and petrochemical wastewaters. The COD test is limited
to a lesser extent such as resistance of some compounds to
chemical oxidation and chloride interference. However, TOG and
TOD analyses can be used to effectively supplement BOD and COD
data for proper organic interpretation.
10. The BOD/COD or BOD/TOC ratio of untreated refinery or
petrochemical wastewaters is indicative of the degree of biologi-
cal treatment obtainable, The possibility of physical or chemical
methods of treatment should be considered when the BOD/COD ratio
is in the range of 0.1-0.4.
11. As effluent criteria imposed by the various regulatory
authorities become more stringent, water reuse will become more
attractive. Attention should be given this possibility when
conducting surveys and treatability studies so that the necessary
information can be integrated into engineering designs.
12. There is no standard format for conducting wastewater
surveys or treatability studies. At present, such projects are
conducted by consulting engineers, equipment manufacturers, and
industrial personnel, either individually or collectively. This
results in many diverse approaches toward the development of
problem solutions. Regardless of the entity conducting the survey
and treatability study, a more uniform, but flexible, format
should be established.
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13. Many petrochemical and refinery waste treatment
facilities have and are being built without the benefit of
adequate survey and treatability data. In many instances,
this results in the discharge of an effluent of lower quality
than permitted with the consequent loss of time and money to
the industrial facility. The regulatory authorities can en-
courage the practice of more extensive pre-construction survey
and treatability studies through treatment process requirements.
14. The pilot or bench scale approach to developing design
criteria is better documented for primary and secondary conven-
tional treatment processes than for tertiary treatment. Generally,
the larger the scale of the test unit processes, the more accurate
the data when compared to full-scale operating information.
15. To date, little scale-up information from pilot or bench
scale to full-scale units is available. This lack of information
can result in the overdesign or underdesign of treatment systems,
even if an accurate survey has been performed and a comprehensive
treatability study has been conducted.
16. Three general levels of personnel are required to perform
wastewater surveys and treatability studies. These include project
managers or specialist-type consultants for project management and
data interpretation, project supervisors responsible for the day-
to-day implementation, and technical assistants to perform routine
operations and analysis.
17. Although many of the larger petrochemical and refinery
industries conduct surveys and treatability studies in-house,
consulting engineers and equipment manufacturers will continue
to be responsible for a major portion of this effort.
18. Costs for conducting surveys and treatability studies
depend on the quality, quantity, and pattern of flow of the waste-
waters. The complexity and age of the petrochemical plant or
refinery also influence this cost. Directly, the costs are re-
lated to the type of personnel utilized, the number of analyses
to be performed, the pilot or bench scale equipment required,
and the complexity of resolving the data. In many cases, budgetary
considerations constrain the scope of the survey and the treata-
bility study. This constraint may result in subsequent capital
losses attributed to overdesign, operational surcharges, etc.
19. Comprehensive surveys and treatability studies for petro-
chemical and refinery facilities are an integral part of the pre-
liminary analytical and engineering phases leading to optimum
implementation of project pollution control programs. Economic
benefits in both construction and operation can result from the
optimization of design which is possible when such data is avail-
able to the designer.
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RECOMMENDATIONS FOR
IMPROVING TECHNOLOGY OF PRELIMINARY INVESTIGATION REQUIREMENTS
A review of this treatise, developed from experience in the
field and from case histories cited in the literature, leads to
the following recommendations. These include suggestions for
improving technology of preliminary investigation requirements
necessary for successful pollution abatement programs in the
petrochemical and refining industries:
1. The quality of wastewater discharged from standard
process units within a refinery such as crude units, catalytic
cracking units, coking units, utility areas, etc., can be cate-
gorized with respect to major contaminants. Therefore, attempts
should be made to survey and statistically report data available
from operating refineries. Such information would greatly en-
hance the programming of wastewater surveys in refineries where
this information is not now available as well as provide some
design bases for treatment facilities serving refineries not
yet constructed. It is recognized that such a tabulation
should be limited to "standard" production units. Applicable
characterization parameters for each "standard" unit also
should be listed.
2. Particular emphasis should be given to the development
of a monitoring and alarm system within a refinery or petrochemi-
cal complex. This includes the detection of specific substances
resulting from batch dumps or spills which adversely affect treat-
ment process efficiencies and/or the biology of the receiving
environment. Such substances include specific organics, refrac-
tory hydrocarbons, heavy metals, etc.
3. As more treatability studies are performed and docu-
mented and treatment facilities constructed therefrom, more
sophisticated scale-up factors should be defined. This is par-
ticularly true when considering biological and chemical-physical
treatment systems. This can be achieved by obtaining operating
data from the bench, pilot, and full-scale units and analyzing
and relating the data statistically.
4. A more comprehensive evaluation of the impact of storm
flow runoff on treatment facilities and surrounding areas should
be included in any wastewater survey. This information then
should be included in the treatability evaluations if such flow
is judged to significantly influence test system responses.
5. A better-defined bench or pilot scale approach for simu-
lating and determining the effects of occasional pollutional dis-
charges such as those from ballast handling areas to a treatment
system should be developed.
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6. The design of continuous flow wastewater treating pro-
cesses should always be based on data developed from continuous
reactor treatability studies. Semi-continuous or batch reactor
studies should only be conducted when a similar operation is
expected of the full-scale system. When carefully interpreted,
studies made using batch and semi-continuous reactors can serve
as screening tests for detecting toxicity, or for roughly esti-
mating continuous flow process performance.
7. It is recognized that sludge handling and disposal
facilities may constitute a significant portion of both con-
struction and operating costs for a petrochemical or refinery
waste treatment plant. These sludges include oily sludges,
chemical sludges, or excess biological sludges. Consequently,
an integral and important part of the treatability study should
be the development of data to allow intelligent selections and
accurate sizing of processes for handling these sludges.
8. There is a need to develop a rational and more uniform
approach toward bench or pilot scale analysis of tertiary treat-
ment processes, particularly as more tertiary plants are put
into operation providing operational data available for treata-
bility evaluation.
9. A more uniform approach in conducting surveys and
treatability studies is suggested through the preparation of
"Standard Methods"-type treatability manuals. Such documents
should incorporate the ideas and approaches of qualified
specialists and be published through sponsoring organizations
such as the American Petroleum Institute or the American
Association of Professors in Sanitary Engineering.
10. The necessary survey and treatability information should
be available before any industrial treatment facility is designed.
In order to be reasonably certain that the pollution control
system envisioned will satisfy the requirements of the industry
and regulatory authority; it is necessary that a comprehensive
survey and treatability program be required. This requirement
can be satisfied through the proper establishment of guidelines
by the regulatory agency and/or industry management.
11. Wastewater surveys and treatability studies should re-
flect the possible influence of shift changes, week-end operations,
seasonal variations, etc., on the wastewater characterization and
its treatability. The more accurately these variations are docu-
mented in the preliminary phases, the greater the probability of
of optimum plant design being achieved.
12. As many new instrumental approaches for analyzing waste-
waters currently are being introduced, an evaluation of the in-
strument performance with respect to analytical efficiency,
interferences, and general limitations should be documented by
independent sources.
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INTRODUCTION
The purpose of this report is to compile and organize the
many components which constitute a preliminary wastewater treat-
ability study for the refinery and petrochemical industry. The
preliminary investigation of petrochemical and refinery waste-
waters and the factors essential for the development of design
criteria for pollution abatement and control facilities are included.
Background information relative to present pollution control
programs within the refining and petrochemical industry, including
applicable treatment processes, current design practice, problem
areas, and trends in pollution control programs within the industry
are presented in the introductory chapter.
SOURCES OF WASTEWATER
The sources of wastes emanating from refinery and petrochemical
operations can be divided into five general categories (Rice, et al,
1969):
1. wastes containing a principal raw material or product resulting
from the stripping of the product from solution;
2. by-products produced during reactions;
3. spills, slab washdowns, vessel cleanouts, sample point over-
flows, etc;
4. cooling tower and boiler blowdown, steam condensate, water-
treatment wastes, and general washing water; and
5. storm waters, the degree of contamination depending on. the
nature of the drainage area.
The principal contaminants in the wastewaters include organics
from residual products and by-products, oils, suspended solids, acidity,
heavy metals and other toxic materials, color, and taste and odor-
producing compounds. The concentration of BOD^ and COD respectively
in untreated refinery effluents has averaged 108 and 204 pounds per
1,000 bbl of crude oil refined (API ,1960; Forbes and Witt,1965; Huber,
1967; Weston and Hart,1941). The pH of refinery wastewaters is
normally alkaline, but may vary considerably depending on disposal
of spent acids, acid washes, etc.
The large variety of compounds produced within the petrochemical
and refinery industries makes the task of treating wastewaters difficult
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and complex. Wastewaters from plants manufacturing similar or even
the same compounds usually display dissimilar characteristics. This
can be ascribed to the use of different manufacturing processes coupled
with the fact that the by-product disposal pattern may occur in a
number of different ways. Hence, a wastewater treatability study
should be undertaken when the treatment of petrochemical and refining
wastes is considered.
WASTEWATER TREATMENT METHODS
A detailed treatability evaluation of each waste stream is a
prerequisite to determining the proper integration of unit processes
which constitute an optimum waste treatment system. The waste treat-
ment methods applicable to the refining and petrochemical industries
can be categorized as follows: physical, chemical, biological, special
in-plant methods, and ultimate disposal (The Cost of Clean Water*1967).
Physical methods include gravity separation, air flotation,
filtration, centrifugation, vacuum filtration, evaporation, and carbon
adsorption. Gravity separators and air flotation units, which are
used extensively throughout the industry, are designed primarily
for removal of free-floating oil and settleable solids. Filtration
is used primarily as a pretreatment for deep well injection; and
centrifugation and vacuum filtration are used for sludge dewatering.
Evaporation ponds are often efficient, but are limited to areas where
land is available and climatic conditions are favorable. Carbon
adsorption is used to remove refractory organic substances.
Chemical treatment methods include coagulation-precipitation,
chemical oxidation, ion exchange, and chemical pretreatment or sludge
conditioning. These methods enhance oil and solids removal, particu-
larly with respect to oil emulsions.
The biological treatment methods include activated sludge and
its modifications, trickling filters, aerated lagoons, and waste
stabilization ponds. Usually some form of wastewater pretreatment
is required to remove oils, suspended solids, and toxic substances,
and to provide neutralization, equalization, and surge or holding
capacity. The activated sludge process is generally considered the
most effective biological process for removing organic materials with
removal efficiencies in the range of 70 to 95 percent for BODc, 30 to
70 percent for COD, and 65 to 99 percent for phenols and cyanides
(The Cost of Clean Water,1967). The conventional activated sludge
process is the most widely applied. Contact stabilization is most
applicable when a large fraction of the organic constituents is in
suspended or colloidal form. Extended aeration is particularly
adaptable to industrial applications as the longer detention periods
allow the microorganisms more time to degrade the complex organics
and, more importantly, sludge production is minimized.
-2-
-------
Deep w«ll injection of petrochemical and refinery wastewaters
is used primarily as an ultimate disposal method for low-flow, highly
concentrated wastes. The efficacy of disposing of these streams by
deep well injection depends on the extent of pre-injection treatment
requirements, the receiving formation, and the risks involved in
contaminating overlying or underlying aquifers.
The more important in-plant treatment control methods include
stripping and recovery operations, neutralization and oxidation of
spent caustics, ballast water treatment, slop oil recovery, and
temperature control. The practice of such in-plant treatment
methods not only reduces the waste loadings to the treatment facility,
but also enhances its performance. In some cases, in-plant control
will show a cost credit in the form of product recovery.
An integral part of in-plant treatment procedures is adequate
in-plant waste control practices. In-plant control techniques include
salvage of unreacted chemicals, recovery of by-products, multiple
reuse of water, good housekeeping techniques to reduce leaks and
spills, and curbing and diking of drainage areas. These controls
can reduce both the volume and concentration of pollutants requiring
treatment.
New production methods are being directed toward increases in
product yield, often resulting in reduced amounts of by-products and
unused raw materials in waste streams. A more general indication of
pollution reduction by in-plant processing practices is the much
lower pollutant loadings per unit of throughput for "newer" refineries
as compared to "older" refineries (The Cost of Clean Water,1967).
CURRENT DESIGN PRACTICE
To date, biological treatment methods have afforded the most
economical secondary treatment processes for pollution abatement. In
order to minimize biological treatment costs, several pretreatment
processes have been adopted, depending on the characteristics of the
waste streams being treated. Design of biological treatment units
must consider the possibility of spills, storm runoff, ballast water
handling, variation in flow and contaminants, and toxic or inhibitory
substances. Completely mixed activated sludge units, therefore, are
applicable to dampen these fluctuations and inhibitory effects.
Aerated lagoons are often used where the waste has a large volume
but relatively low concentration of dissolved organics. Anaerobic
lagoons, anaerobic contact units and high rate trickling filters are
used individually or conjunctively when high strength wastes are
involved.
Facilities for handling the treatment of the accumulated primary
and biologically synthesized sludges often represent a major portion
-3-
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of the treatment facility costs. One inexpensive method of disposing
of sludges practiced in many parts of the country is lagooning. How-
ever, dewatering the sludge to reduce the volume or direct disposal at
sea or in remote areas may be more favorable alternatives where land
is unavailable. Aerobic digestion is presently favored over anaerobic
treatment in industrial waste applications and is generally followed
by thickening, vacuum filtration, filter pressing, or centrifugation
and ultimate disposal by incineration or trucking.
PROBLEM AREAS
The problem areas encountered in the treatment of wastes dis-
charged from the refining and petrochemical industries are generally
those associated with pretreatment and biological treatment systems.
Problems may be attributed to process changes or modifications,
accidental spills resulting in the discharge of slugs of contaminants,
or poor in-plant management.
Problems related to pretreatment processes may be caused by
excess concentrations of free and emulsified oils, high or widely
fluctuating temperatures, acidity or alkalinity, or other contaminants
which adversely affect process operation.
Waste oil usually occurs from leaks, spills, washing operations,
and rainfall runoff from oily areas. When oily wastes and water
commingle, there is always a good chance for emulsification, which
sometimes is difficult and costly to break.
Wastes affecting pH in the refinery and petrochemical industries
include strong acids and alkalies as well as dissolved solids which
often buffer their effects. Spills, leaks, scrubbing operations,
and point discharges of spent acid are the main sources of acid
wastes while the main contributor of acidity is sulfuric acid.
However, HC1, H2S, HF, and CC>2 contribute to a lesser extent to the
acidity of the wastewater. Alkalies from process neutralization,
process operations, and kettle washes are the main sources of alkalinity.
The oxygen demand of refinery and chemical wastewaters is
probably the most important factor to be considered. The most
concentrated oxygen-demanding wastes discharged from a refinery
usually occur in the crude and cracking units. Although much of
this oxygen demand in terms of BOD, TOC, COD, etc, is attributable
to the oily fraction, a significant portion results from the presence
of lighter hydrocarbon contaminants. Moreover, substances such as
sulfides and various nitrogen compounds are responsible for an
additional oxygen demand.
Toxicity to living organisms is a critical factor in evaluating
the treatability of chemical and refinery wastes. Ammonium salts,
-4-
-------
sulfides and polysulfides resulting as wastes from the use of
ammonia as an anticorrosive agent, as well as other boiler and
cooling tower inhibitors are toxic. Heavy metals used as catalysts
or preparants in process operations are other sources of pollutants
which may be toxic to living organisms.
The taste and odor-producing wastes resulting from washing
high sulfur crude oil, or cracked distillate from high sulfur stocks,
may have highly noticeable and persistent odors. The odor is attrib-
utable to complex organic sulfur compounds and alkylated substances.
Acid sludges are the next most important group responsible for
taste and odor problems. Sludges from the acid treatment of light
distillates have a much more pronounced odor than those from the
treatment of lubricating stocks. Much of the odor from light oil
sludges is due to mercaptans, which are disagreeable and can be
detected at concentrations of a fraction of a part per trillion.
Large concentrations of sulfides in biological treatment units
impair the treatment efficiency of these units because of the oxygen
required to satisfy the chemical oxygen demand or the possible inhibi-
tory or toxicological effects on the system bacteria. Preaeration
of sulfide wastes results in stripping the sulfide from solution when
the wastewater is acidic, or oxidizing the sulfides to thiosulfate or
sulfate at high pH values.
SOLID WASTE DISPOSAL METHODS
A historical survey of the trends in solids disposal at refineries
and petrochemical plants indicated that this is a significant problem
with most industries. Landfill was found to be the most common
method of disposal and was used primarily for separator and tank
bottom sludges, sewer cleanings, water treating sludges, cooling
tower bottoms, and biological treatment plant sludges. Incineration
and open burning has been used for general refuse. Contract dis-
posal services have been used for filter cakes, treating clays, and
slop oil disposal.
Based on the results of this survey, it was decided that further
information on the following areas would improve the disposal techniques
available:
1. determination of hydrocarbon content and calorific values
of solid wastes,
2. evaluation of incinerators to establish capabilities for
handling different wastes,
-5-
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3. investigation of land spreading techniques to establish land
and manpower requirements,
4. identification of wastes that are amenable to de-oiling
treatment, i-£., separation of solids and hydrocarbons, and
5. investigation and development of spent caustic disposal
systems.
RECOMMENDED APPROACH FOR SUCCESSFUL POLLUTION ABATEMENT PROGRAMS
The successful result of a pollution abatement program depends
on a number of carefully integrated procedures designed in cooperation
with and dependent upon each other. These procedures are divided
into 6 steps illustrated in Figure 1. Consideration of the sources
and quantity of pollutants should be made during the research and
design phase of an industrial plant and this should be performed
prior to the construction of new facilities or additions. One
procedure which has been applied to refineries in the design and
planning stages is to estimate the mass balance around each unit
processes as well as process areas (Sun Oil Company, 1969). Alteration
of the design of various units to minimize wastewater flows and the
incorporation of new and more efficient processes are the most
obvious means of reducing a source of pollution. The objective of
the wastewater survey is to determine all sources of wastewaters
and obtain representative samples of those available. The future
sources and potential problems should also be considered during
the survey.
While no one unit process can effectively treat refinery and
petrochemical wastewaters, there are combinations of biological,
chemical, and physical processes which can be used to stabilize the
wastewaters. Although these wastewaters often have biological inhibi-
tors, recent studies have shown that the activated sludge process
(Engineering-Science, Inc./Texas, Delaware Study; Kerberger and
Barnhart, 1970) and algal stabilization ponds (Copeland and Dorris,
1964; Copeland, Minter and Dorris, 1964) are relatively unaffected
by various refinery wastewaters provided the proper safequards
are designed into the facility.
When secondary and tertiary treatment are necessary, the ultimate
step of closing the water-wastewater loop becomes a valid consideration.
The economics of closed-loops within an industry or within a muni-
cipality have already been realized in many cases (Partridge and
Paulson, 1967; Cecil, 1969).
-6-
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VSASTE WATER
SURVEY
Present, future and
potential wastes
" ' \*X^^
WAXTEWATi'K
CHARACTERIZA-
TION
Organic and inorganic
characteristics
IN-PLAN
1
Eliminate wastewaters
at their source
PRESENT
PREDETERMINED
EFFLUENT QUALITY
RESEARCH
DESIGN
Minimize and
eliminate waste
streams
FUTURE
FIGURE l
SEQUENTIAL STEPS REQUIRED TO MINIMIZE AND ELIMINATE THE POLLUTIONAL
EFFECT OF WASTEWATERS FROM REFINERY AND PETROCHEMICAL INDUSTRIES.
STUDY
Optimal treatment
processes required
V
INCORPORATION
OF RESULTS
Utilization of
Recommendations
-7-
-------
THE WASTEWATER SURVEY
The wastewater survey must contain detailed information on
waste flows, characteristics of the flows, and relevant environmental
conditions in order that sound engineering decisions regarding the
wastewater treatment can be made. Design data for wastewater treat-
ment facilities should include but not be limited to the following:
1. the source of all significant waste streams;
2. samples at points where significant changes in waste charac-
teristics or quantity of flow occur;
3. samples which reflect the benefits from segregated sewer
systems;
4. consideration of water reuse and water saving process
modifications;
5. consideration of overloading of waste treatment systems
resulting from unit shutdown, startups, turn-arounds,
accidental dumping or spills, and other shock loadings;
6. investigation of reducing waste streams by eliminating
or decreasing flows by process modifications; and
7. evaluation of wastewater sources related to variable
occurrences such as storm flow drainage.
A complete audit of all water and contaminants entering and
leaving a process or drainage area would yield sufficient informa-
tion to satisfy the objectives of a wastewater survey. Practically,
however, this mass balance is seldom possible to achieve due to
unexpected and unknown variations in raw materials, chemical inputs,
process operations, etc. Constraints placed on the industry such
as required quality standards, limited financial resources, and
pollution abatement policies often dictate the scope of a waste-
water survey. This chapter presents a practical engineering approach
to obtaining the necessary information.
SAMPLING STATION SELECTION
Petrochemical and refinery liquid wastes may be classified
as clean or highly contaminated process streams, clean and con-
taminated storm systems, and sanitary waste streams. The
selection of wastewater sampling sites should be based on ob-
taining characterization data for each of the applicable categories,
since segregation of wastewater conveyance systems gives more
flexibility in solving pollution control problems.
-8-
-------
A number of sources of clean, oily, and sanitary refinery
wastewaters are identified in Figure 2 and the more common sources
of highly contaminated wastewaters are summarized in Figure 3.
In any wastewater survey it may be necessary to determine the
capacity and effectiveness of existing in-plant processes such as
those shown in these Figures.
"Clean" process streams normally are those discharged from
cooling and boiler utility areas and from general washing operations.
Under most operating conditions, 85 to 95 percent of the water
used in petroleum refineries is for cooling purposes (API,1968).
In "once-through systems" the major change in water quality will
be only an increase in temperature. Recycled cooling water may
have high salt concentrations due to evaporation loses as well as
high concentrations of chromate or other toxic materials added for
prevention of corrosion and/or growth of microorganisms. Other
streams with relatively high concentrations of dissolved solids,
i.e.., boiler blowdown, neutralized demineralized resin rinses,
etc. . can be included. However, streams that may become contaminated
with oil should be excluded. Thus, although organic contamination
of these waters is usually not a problem, thermal considerations
and the total dissolved solids concentration warrant careful
attention.
Highly contaminated process streams include those streams
containing concentrated organic materials, high concentrations of
toxic substances, significant concentrations of oxygen-utilizing
material (chemically and biologically oxidizable), extremely acidic
and alkaline wastes, and oily streams containing high dissolved
solids. These wastes usually originate from process operations,
cleaning and washing, or accidental leaks or spills. Process
discharges are caused by reaction products created by impurities
in the feedstock, raw or partially reacted feed chemicals resulting
from low process conversion efficiencies, and by-product formation
in the chemical reactor.
Acidic wastes are among the most important wastes of petroleum
refineries and originate principally in the treating plants, acid
recovery areas, alkylation units, some water treating plants, and
in some special product operations. They result from washing of
intermediate petroleum products which have been acid treated, and
from leakage and spills around these process areas and the leaching
of acid wastes by rainwater.
Excessive alkalinity is normally not a problem although waste
caustic or caustic sludges often merit special consideration. It
varies in composition and appearance, depending on the crude
being processed or the oils being washed. Waste causticity
resulting from washing crudes and mixed paraffinic and naphthenic
substances contain about 0.3 percent unreacted caustic soda, sodium
sulfide, sulfate, sulfite, thiosulfate, phenol, mercaptans, and
other organics.
-9-
-------
OILY WATERS
(1) Sc rrumn with h 1 K^ content of diBBolvcd sol Ids(Inorganic sal ts)
to he excluded ,
(2) Streams containing phenols, sulfldes, amnonla, high BOD and COD,
etc., to he excluded.
ProccsB ori-a drains {, oily utility area drains
Coo I I HR wat e r I rom pump & compres sor Jackets, glands, pedestals, etc.
T-ink diked a rtM tl rn I ns (vulvnl to permit controlled drainage of
8 t orm-wa t e r s )
Tank hot t um J raw* (whi'rt1 phenol a, su 1 I 1 des , TEI,, Baits are not present
Laboratory Water After-Scrubs Steam-Stripped
Drains (following caustic scrubs) Waters
1.1 nk hot t ixn draws * win- n.1 phcno 1 «
9u 11 Ides und salts arc present).
C I rcula t 1 HK C oo I I ny, W.iter 'i) owdown
( hromate RemovalI
Oner-through cooling water (cooling pentane & heavier process streams)
Tanker ballast (pumped at hl^h rate)
Stor/i^e Tanks
(pumped at reduced ratc^J
bk 1m oil
DEMIS'ERALIZEK R£SIN KINSLS.
ut r.il l/.ur Suinpl
N WAI I 1
(1) Streama with hl^h content of dissolved solida (Inorganic suite)
may be Inc luded
(2) Oily streams must he excluded.
Stormdralns (from non-tank and from non-process areas)
Utility area drains (where oil will not be present)
Holler blowdowns
Once- through cool ing wate r (cool ln^ butane 4 Lighter process tr earns )
Cooling Tower hi owdown
St unm turbine condenser wa tc r
ALr conditioning cooling water
V.atcr Treatment filter backwash
-AlLernate--
when oil
leaks occur
>
f. rom o
of sulft
and sulfl
r ^
xldatlon
die caustics
^
Crude
Deaa
effl
wac
' i
Oil
Uer
uent
er
y Ulyh Con t ami n.it 1 on Sewer
API 1
Separator
I
Chemical Coagulation
OR T°
Secondary
when otl_
1 t-aks occur
MAIR ^^^^^ Treatment
Flotation! ,
T JT
skim oil sludge froth sludge
Oily Water SUWIT
(also surge for cooling
water when oil leaks
occur)
He-use a« cooling wa
(underground)
skim oil sludge froth sludge
Clean Watrr Scwc r _^ [ Kmcrguncy
skim oil
S/inltary Wastes
1
.
Pack me Plant or 1
Septic Tank or 1
Discharge to 1
H
To
Holding
"Balln
FIGURE2
SEWER SEGREGATION AND OIL REMOVAL
--10-
-------
SULFIDIC
SPENT
CAUSTICS
(1)
SULFIDIC
SOUR WATERS.
("2S/NH3
PHENOLIC
SOUR WATERS
and Phenols)
PHENOLIC
SPENT CAUSTICS
(4)
WATER AFTER-SCRUBS
(following caustic-scrubs)
V >y >r
SOUR WATER
STEAM
STRIPPER
BAROMETRIC
CONDENSER WATER
t
R
^ SPRUNG
NE
1
(3)
(6)
>
t
SPKNT
CAUSTIC
NEUTRAL I ZER
WATER
(2)
(or Co 5«lea)
PUMP GLAND
COOLING WATER
Acid Oils
(to sales)
CRUDE OIL
DESALTEK
Re-use water
(5)
LABORATORY
DRAINS
CHEMICAL WASTES
(Special facilities required
for spent acids, TEL, amines,
furfural, MEK, mineral aclda,
sludges, etc.)
TANK
DRAWOFFS
HIGH CONTAMINATION SEWER
(1) Usually steam stripped, If no phenols or oil
present, may be oxidized.
(2) Will contain about 3000 ppm wt. H S, 8000 ppm
wt. phenols, and 15-30 wt.7. sodium salts.
High salt content may cause problems In steals
stripper.
(3) Strtppcr removes about 987. of H S, 957. of NH
and 207. of phenols, pH of stripped water will
be about 9-10, With some crudes, residual NH^
may require acid neutralization-of pi! 6.8-7.0
to avoid formation of soaps in desalter.
(4) May require acid neutralization If caustic
carryover is excessive.
(5) Desalter removes most of the phenols and H_S
from water. This stream will contain 0-10 ppm
wt. H S, 10-25 ppm wt.-phenols, 100-300 ppm
wt. oil, 50-500 ppm wt. HOD.
(6) H S content about 10-150 ppm wt. and NH3 con-
tent about 50-500 ppm wt. pH about 9-10. Will
also contain phenols.
FIGURE 3
IN-PLANT PRETREATMENT OF HIGH CONTAMINATION WASTE STREAMS
-11-
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Contaminated sewers usually contain "oily" wastewaters,
although parallel sewers are provided occasionally to separately
convey oily concentrated and non-oily concentrated waste streams.
Oily sewers are routed to oil separation and recovery processes
such as API gravity separators and air flotation units. This not
only reduces the oil concentration of the unit process underflow
flowing to subsequent treatment facilities, but also provides for
oil recovery through skimming, emulsion breaking, storage, and
reprocessing of recovered oil.
Sanitary waste streams emanating from administrative and
laboratory areas are usually separated from industrial source
discharges in order to prevent chlorinating the total combined
flow. Consequently, these streams are usually separated from the
industrial flow and treated separately.
CASE STUDIES OF WASTEWATER SURVEYS
The following wastewater surveys are presented as case histories
to document typical wastewater surveys. Although the goals and
objectives of the studies cited were different, they represent
typical approaches utilized in conducting surveys to fulfill pre-
determined objectives.
Case History A - Petrochemical Industry
This survey was conducted in a large petrochemical complex
having a total water use of 2.5 MGD. The primary products in-
clude butadiene, olefins, styrene, and nylon monomers.
At the time of the survey, the waste treatment system consisted
of various in-plant recovery devices, oil separation facilities,
neutralization systems, and deep injection wells with appropriate
surface pretreatment units.
The objectives of the survey were as follows:
1. locate and classify major sources of pollution, organic
and inorganic;
2. categorize the major sub-collection systems as to their
amenability to biological treatment, and
3. identify waste discharges with
a. high toxicity potential on the proposed treatment
system and receiving environment, and
b. product recovery potential.
-12-
-------
In order to fulfill these objectives, a comprehensive waste-
water survey leading to the characterisation and categorization
of major waste streams was undertaken. Sampling points were
selected in order to evaluate major sources of pollution. These
sites are graphically illustrated in Figure 4 and are tabulated
in Table 1.
After checking plant operational schedules and programming,
it was determined that a 24-hour survey would indicate typical
flows and characteristics, providing the sampling was sufficiently
frequent and proper techniques of acquiring and compositing the
sample were employed.
The flows of each of the major collection systems were estimated
by measuring the depth and velocity of the partially filled gravity
sewers, using the recorded slopes from construction drawings for
verification. In some instances, the total flow from various loca-
tions within the complex was pumped and the flow charts were used
as the basis of estimating flow. Grab samples were taken at each
sampling station during the 24-hour period and composited according
to flow at 2-hour intervals. These composited samples were then
cooled to 4°C and stored until the survey had been completed. All
samples were then collected and transported to the laboratory for
chemical analysis. The analyses selected for this particular survey
are itemized in Table 2.
Once the analyses had been performed, the statistical distri-
bution of the data was obtained and used in formulating design
criteria. For example, the degree of variation was particularly
significant when considering average values for design parameters.
Additionally, the variation was descriptive of the nature of produc-
tion process operations which is important when conceiving treat-
ment system layout, in-plant modifications, or factors of safety
to be incorporated into the sizing of the system.
The general conclusions resulting from this survey of the
petrochemical plant as described herein can be summarized as
follows.
1. The wastewater from network "A" was found to have a low
volume of flow, although high concentrations and variability
of dissolved organic and inorganic constituents were
observed.
2. The network "A" stream analysis indicated the presence
of some product spills and generally poor in-plant
housekeeping. Concurrently, product recovery potential
was indicated and steps were recommended to minimize this
waste stream.
-13-
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WATER TREATER
BRINE 8 RINSE
WATER TREATER
'ACID 8 RINSE
HMD CATALYST
WASHING AREA
RECLAIMED MUNICIPAL
WASTE TREATMENT PLANT
EFFLUENT
ADIPIC ACID
PLANT AREA
WASHDOWN
NITRIC ACID
HOLDING
POND
TO COLD WATER
'WATER STORAGE:
LAGOON,1"
LIME TREATER
OUTSIDE INDUSTRY
WASTE STREAM
PLANT WATER
BUTADIENE COOLING TOWER
SLOWDOWN 8 FILTER BACKWASH
HMD PLANT
COOLING TOWER
SLOWDOWN 8 FILTER
BACKWASH
HEXAMETHYLENEDIAMINE STREAM
NEUTRALIZATION PITp
ACID SUMP 8 HNOi
COLUMN BOTTOMS
OUTSIDE INDUSTRY WASTE STREAM
OLEFIN' COOLING TOWER SLOWDOWN a FILTER BACKWASH
BOILER SLOWDOWN , CRACKER DECOKING
ADIPIC ACID PLANT STREAM
OLEFIN API
AMMONIA COOLING TOWER
SLOWDOWN 8 FILTER BACKWASH
TO INJECTION WELL
WASTE
HCL
STORAGE
BOILER SLOWDOWN
NH3 PROCESS WATER
DEMINERALIZER CAUSTIC
AND RINSE
DEMINERALIZER ACID 8 RINSE
LlfT STATION 8
NEUTRALIZATION
LIME SLUDGE
FROM WATER
TREATER
AREA
REUSE OR TO
DEEP WELL
INJECTION
STORAGE POND
WASH W.AJ_E R
BURN PIT
PONDS
_ _.
V I N Q
FIGURE 4
EXAMPLE OF WASTEWATER SAMPLING STATION LOCATION IN A COMPLEX PETROCHEMICAL INDUSTRY
-14-
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TABLE 1
SAMPLING STATION DESCRIPTION
Sampling Point
Designation Description
NETWORK "A"
1 Hexamethylene diamine area
2 Acid sump and column bottoms (neutra-
lization)
3 Adipic acid production area
4 Total network "A" flow (API Separator
effluent)
NETWORK "B" (Butadiene, Olefin Production Area, Outside Industry Stream,
Blowdown Cooling Stream, Miscellaneous Streams)
5 Outside industry waste stream
6 Butadiene production area (API
Separator effluent)
7 Outside industry waste stream (manhole)
8 Olefin production area (API Separator
effluent)
9 Four through Seven flow plus blowdown,
ammonia process water
10 Total flow
11 Total flow
NETWORK "C" (Treated Sewage Effluent)
12 Treated sewage effluent (sampling port)
13 Municipal treatment plant effluent
14 Catalyst washing area, surface runoff
(open ditch)
-15-
-------
TABLE 1 (Cont)
SAMPLING STATION DESCRIPTION
Sampling Point
Designation Description
NETWORK "C" (Cont)
15 Flare pit settling pond overflow
16 Upstream receiving water
17 Downstream receiving water
18 Nitric acid stream (sampled at
Flare Pit Settling Pond)
-16-
-------
TABLE
ANALYSES COMPLETED IN A WASTEWATER CHARACTERIZATION
STUDY OF A PETROCHEMICAL INDUSTRY
Sampling Point
Analyses Performed
Purpose
NETWORK "A", "B",
and "C"
TOC
COD
pH, alkalinity,
acidity
Total Solids
Suspended
Dissolved
Total Kjeldahl
Nitrogen
Total Phosphate
Sulfates
Chlorides
Oils
Temperature
Degree of organic treatment
required
Neutralization requirements
Pretreatment requirements
Effect on treatment process;
estimate of effluent quality
with respect to that allowable
Nutrients
Nutrients
Effect on proposed treatment
process; effluent quality
requirements
Effect on proposed treatment
processes; effluent quality
requirements
Efficiency of existing oil re-
covery systems; effect on pro-
posed, treatment processes;
effluent quality requirements
Thermal pollution potential;
basis for calculating tempera-
ture balances and effect on
temperature dependent reactions
-17-
-------
3. Preliminary observations of the network "A" stream
indicated difficulty in applying biological treatment
methods for this source individually, without dilution
water from other sources.
4. The network "B" stream had a much higher volume of flow
with much lower concentrations of organic and inorganic
contaminants. The variation of these materials was also
less. However, the suspended solids load from processes
served in this network was higher.
5. The network "B" stream appeared to be more amenable to
conventional treatment applications than did the network
"A" stream, although a preliminary step for removal of
suspended solids would be required prior to subsequent
secondary forms of treatment.
Case History B - Refinery-Petrochemical Complex
The objectives of this survey were different than the one
previously cited in that the effects of the combined flow on an
operating aerated lagoon and its performance characteristics were
to be evaluated.
Generally, the wastewaters included those from refinery
process operations, cooling and boiler units, and miscellaneous
cleaning and washdown operations. Some forms of pretreatment
were given to most streams within the complex. For example, most
oily streams such as those emanating from ballast dumps or in-
plant separations were routed through a series of oil separation
units prior to being pumped into the aerated lagoon.
It was determined that a 24-hour sampling and analysis period
was sufficient to accurately characterize the performance of the
lagoon. The approach in making this evaluation was to measure the
level of organic and inorganic constituents for the influent and
effluent, thus measuring organic removal efficiency as well as
conversion levels of inorganic substances. Concurrently, repre-
sentative sampling profiles were established within the aerated
lagoon basin in order to establish mixing and dispersion patterns
necessary for the proper placement of mechanical surface aerators.
The sampling and analysis schedules for the survey are itemized
in Tables 3 and 4.
The general conclusions drawn from this aerated lagoon survey
are listed as follows:
1. The efficiency of the aerated lagoon in terms of
biological removal of soluble organic materials was
approximately equal to that predicted in preliminary
bench scale treatability studies.
-18-
-------
TABLE
SAMPLING AND ANALYSIS SCHEDULE
INFLUENT AND EFFLUENT STATIONS
Analyses
Frequency
Purpose
BOD (five-day) (mg/1)
BOD (ultimate) (mg/1)
1/hr
1/hr
organic load, plant effluent with
respect to criteria
organic load, plant effluent with
COD (mg/1) 1/hr
Conductivity (mhos/cm) 1/hr
D. 0. (mg/1) continuous
Flow (mgd) continuous
Oils (mg/1) 1/hr
ORP (mv) 1/hr
pH continuous
NH4 - N (mg/1) 1/hr
SS (mg/1) 1/hr
Sulfates (mg/1) 1/hr
TDS (mg/1) 2/hr
Temp <°C) 1/hr
VSS (mg/1) 1/hr
respect to criteria
organic BOD comparison
waste characterization
process control
organic and hydraulic load
process control, toxicity,
efficiency of existing oil
recovery systems
sulfide level; ratio of oxidants
to reductants
process control
nutrients, waste characterization,
potential toxicity
suspended solids loading
sulfide oxidation, wastewater
characterization; effect on
subsequent waste stabilization
ponds
waste characterization
environmental, effect on tempera-
ture dependent reactions
volatile solids loading
-19-
-------
TABLE 4
SAMPLING AND ANALYSIS SCHEDULE
PROFILES WITHIN AERATED LAGOON BASIN
Analysis
Sampling Points
Horizontal
Vertical
Purpose
Every 20 feet
D. 0. (mg/1)
O- Uptake
ORP (mv)
TOG (mg/1)
TSS (mg/1)
Velocity (fps)
I/top
I/mid- depth
I/bottom
One Per Profile mid-depth
Mixing evaluation with
respect to soluble
organic s
0- profiles, anaerobic
areas, zone of aerator
influence evaluation
Evaluate 0- demand of
basin contents; aerator
efficiency
Oxidant-reductant
profile
Mixing evaluation with
respect to soluble
organics
Uniformity of TSS,
effectiveness of aerators
in maintaining solids
in suspension
Velocity profiles,
mixing evaluation
-20-
-------
2, There was an accumulation of heavy oily sludge in the
bottom of the lagoon, indicative of the relatively high
oily solids loading applied directly to the lagoon as
well as the inability of the surface aerators to keep
this sludge in suspension at the power level employed.
3. The power level of 0.05 HP/1000 gallons of basin volume
was insufficient to keep all of the biological solids
in suspension and pronounced gradients of D.O., SS, and
liquid velocities were noted in the lagoon. However, a
small residual D.O. level was noted at most horizontal
and vertical sampling stations within the aerated basin.
4. The rapid increase of D.O. in the aerated lagoon when the
wastewater inflow was temporarily diverted and the equally
rapid decrease when the flow was returned to the lagoon
indicated that the microbial floe was viable and active.
Case History C - Petrochemical Complex
A survey of this petrochemical facility producing polyester
resins was conducted in order to determine the feasibility of
treating the liquid wastes using biological methods. Although the
plant produced a relatively low total waste flow in terms of
volume, the wastewater organic concentration was highly fluctuative.
The sources of wastewater discharged from the facility were
categorized as follows:
1. Process wash and rinse - this wastewater results from
periodic cleaning of reaction vessels;
2. Base flow - a composite of wastewaters discharged from a
multitude of sources exclusive of those derived from
scrubber or process wash/rinse operations;
3. Storm runoff - the portion of storm drainage which comes
in contact with contaminated areas; and,
4. Scrubber blowdown - from intermediate product washes.
The average COD and pH of these four waste streams are given
in Table 5. The final recommendations of this survey included:
1. segregation of the highly concentrated scrubber blowdown
from the remaining waste streams using liquid incinera-
tion as the disposal process; and,
2. altering the collection system for the remaining waste
streams, including storm water, to be discharged to a
single point and treating this flow biologically.
-21-
-------
TABLE 5
WASTEWATER CHARACTERISTICS FROM A SMALL PETROCHEMICAL INDUSTRY
Description of Waste Source
Intermittent Washing Operations
Base Flow From Process Operations
Storm Runoff (Design Basis = Two-Year
Storm)
Off-gas Scrubber Slowdown
COD
(mg/1)
6,000
2,500
2,000
100,000
PH
variable*
8.0
1.5
* Depends on Whether Process Wash or Process Rinse is being discharged.
-22-
-------
This concept was complicated to some extent because of the
discontinuous pattern of flow. However, the impact of variable
loading was sequestered by providing a completely mixed bio-
logical treatment basin sized for excess capacity. The results
of continuous monitoring of all wastewater from this industry
prior to in-plant segregation and equalization is shown in
Figure 5 while the effect of in-plant changes and equalization
is shown in Figure 6.
Case History D - Petrochemical Complex
This survey is cited to document the significance of storm
runoff as a source of pollution. Rainfall information for this
small petrochemical complex producing polyester resins was ob-
tained from the Weather Bureau and the calculated volume of
runoff for several 24r-hour design storms is given in Table 6.
A runoff coefficient of 0.90 was used to estimate these volumes
accumulating from the 13 acre contaminated area of the plant.
Samples of runoff were taken during storm conditions and COD
values up to 2500 mg/1 were reported during the peak portion of
the flow. Recommendations were made to provide retention facili-
ties to store the first 15 minutes of runoff resulting from a
5-year storm, then discharging this contaminated /olume of water
to the biological facility over an extended period of time. It
is impractical in most cases to provide retention ponds when
production and storage facilities encompass large areas. The
calculated storage required to retain the contaminated fraction
of a 5-year storm from one refinery complex occupying several
thousand acres, for example, is 235,000,000 gallons (Engineering-
Science, 1969).
Case History E - Chemical Complex
Storm runoff presented a different problem for a reprocess-
ing chemical facility as shown in Figure 7(Gloyna, Ford and
Eller, 1969). Samples were collected at the storm collection
sump for each of the 6 contaminated areas. The varying mag-
nitudes and patterns of runoff COD enabled the engineers to
make decisions for collecting, storing and reprocessing the
concentrated portion of the storm flow while using the less
concentrated waters for boiler and cooling tower make-up.
This approach not only provided credits in terms of recovering
product and reducing fresh water make-up requirements, but also
reduced the volume of contaminated storm runoff leaving the
property of the chemical plant.
-23-
-------
13
I I
9
PH 7
3
I
PROCr.SS DUMP
30
PROCESS DUMP
PROCESS WASH
PROCESS WASH
PROCESS DUMPS
10
FLOOR WASH
16 24 06 12 18 24 06 12 18 24 06 12 18 24 06 12 18 24 06
FIGURE 5
FLOW VARIATIONS RESULTING FROM BATCH UNIT PROCESS OPERATION IN A PETROCHEMICAL INDUSTRY
-24-
-------
13 _ . . .
1 |
A
oH 7 ~
" * r - - - - - - - -'- - - - - -
3
i
' -
40
30
£
0
0 20
_l
u.
10
°l
._-
- -
-
1
- 1 1 1 1 1 1 I
I 16 2
-, IST njtv B-
10
"ft
in
L-^
i i i i i i i i i i i
4 06 12 16 2
m *N0 HAY »
^n
7O
^AREA WASH
\ PROCESS
10 ^ C
^^}.
BOILER SLOWDOWN
i i 1 i i i i i i i i
4 06 12 18 2
« VtD HAY »
in
Ort
cU
HOSE LEFT ON
/
DUMP^^^
i i i i i i i i i i i
4 06 12 18 2
-i ATH n' ^
~^f\
*tt\
i\j
PROCESS DL
V-
-TO "^ -S
1 1 1 1 ! 1 1 1 1 1 1
30
cU
MP.
"/
irt
IU
1111"
4 06 12 18 24 06
era n AV - fru njiis
* Oui UAi **
~-O< UHI
FIGURE 6
OBSERVED FLOW VARIATIONS FOR PROCESS EFFLUENT SHOWN IN FIG. 5 AFTER EQUALIZATION BASINS.
-25-
-------
TABLE
STORM OCCURRENCE AND QUANTITY OF RUNOFF FROM A
PETROCHEMICAL INDUSTRIAL AREA*
Recurrence
Interval
(Years)
Total 24-Hour
Rainfall
(Inches )
Estimated Total
Runoff
(Gals. )
1
2
5
10
25
4.05
5.35
7.25
8.7
10.05
427,900
565,300
766,000
919,200
1,061,800
*Runoff Coefficient Taken To Be 0.95; Approximate Drainage Area is 13 Acres
-26-
-------
5000
4000
E 3000
eS
8 2000
1000
.5 LO 1.5 2.0 2.5 3.0 3.5 4.0
Cumulative Rainfall, inches
0 .5 1.0 1.5 2.0 2.5 3.0 3.5 40
Cumulative Rainfall, inchn
5000
4000
f 3000
o
8 2000
1000
.5 1.0 I 5 2.0 2.5 3.0 3.5 4.0
Cumulative Rainfall, inches
5000
4000
f 3000
§ 2000
1000
.5 1.0 1.5 2.0 2.5 30 3.5 4fl
Cumulative Rainfall, Inchei
.5 1.0 1.5 2JO Z5 3.0 35 4.0
Cumulative Rainfall, inches
.5 m 1.5 20 2.9 3fl 3.9 4.0
Cumulative Rainfall, Inchn
FIGURE 7
ORGANIC CONTAMINATION OF RUNOFF
-27-
-------
PROGRAMMING AN INDUSTRIAL WASTEWATER SURVEY
An industrial wastewater survey should be planned and organized
to obtain the maximum amount of significant data with a minimum
expenditure of time and money. The survey must include proper
sampling techniques at the right locations, sufficient analyses
to characterize major pollutants, and be conducted for a sufficiently
long period of time to provide reliable statistical inferences.
Sampling Techniques
The most comprehensive wastewater survey may be programmed
and completed with a gross misrepresentation of wastewater
characteristics unless proper care is taken to choose the correct
sampling techniques. The chosen technique must meet two basic
requirements: the sample must be homogenous and representative
of the mass sampled, and it must be sufficient for subsequent
laboratory examination.
Methods of obtaining samples can be generally classified into
two categories; instantaneous or grab samples, and integrated or
composite samples. A grab sample is a portion of the waste singu-
larly collected and used as a spot check of the characteristics of
the wastewater. In instances where there is a minimal variation
of waste characteristics, a grab sample can give sufficient repre-
sentation. Numerous grab samples can be used to trace the waste
variations with proper consideration of sample volume regarding
both analyses requirements and volume required for compositing in
proportion to flow. Note that compositing techniques should in-
clude thorough mixing of each grab sample while compositing to
prevent sedimentation of solids.
Continuous sampling is necessary where the waste fluctuates
rapidly over a relatively long period of time. Continuous
sampling over a 24-hour period is usually adequate, except for
waste from "batch dumps" and "turn-arounds" typical of the
refinery and petrochemical industries. Periodic grab samples
correlated with flow measurements will usually be adequate to
describe waste from intermittent sources such as "batch dumps."
Continuous samples may be collected automatically in proportion
to the flow and composited in one container or the continuous
sample may be segregated on an hourly basis (or otherwise, de-
pending on the wastewater characteristic variation). Continuous
compositing will yield an "average" wastewater and is adequate
where variations are minimal. If, for example, the pH is low
half the time and high for the balance of the flow period, a
continually composited sample may indicate a neutral waste. In
these instances, a segrated composite sample is necessary.
-28-
-------
The strict definition of a semi-continuous sample taken over
24 hours, _i._e., a "24-hour composite sample", may be given as
follows (California, 1965): "24-hour composite sample" means an
influent or effluent sample composed of individual grab samples
mixed in proportions varying not more than plus or minus 5 percent
from the instantaneous rate of waste flow corresponding to each
grab sample. These are collected at regular intervals, not
greater than 1 hour, throughout any period of 24 consecutive
hours, or collected by the use of continuous automatic sampling
devices capable of attaining the proportional accuracy stipu-
lated above.
A "grab sample" may be defined as an influent or effluent
sample collected at any time from any point at which the sample
will contain all wastes discharged through the outfall(s), or a
receiving water sample collected at any time from any point in
the receiving waters.
Numerous automatic continuous sampling devices can be either
purchased or constructed on site. Perhaps the least complicated
is where a continuous sample is pumped into containers which are
changed automatically for a predetermined time period. Composite
samples can be obtained using this sampling method and a con-
current record of the flow.
In cases where the waste stream is hard to reach, where
economics demand the most inexpensive approach, and less exact
data is required, the simple sampling setup known as the tipping
bucket may be applied. This continuous sampling device is one of
the most efficient and inexpensive methods cf obtaining accurate
flow information while obtaining a proportionate sample. In this
method, a container is constructed such that the center of gravity
shifts and causes the bucket to empty itself when the waste fills
the vessel. Each dump is measured by a mechanical counter to
give the flow variation with time. A small built-in sampling
device fills each time the container fills and empties when the
container tips. The proportionate sample may either be composited
in one vessel or segregated for individual analyses. This method
is easily adapted to waste flows of 0.1 to 20 gpm.
In order to insure the .homogeneity of the sample, it is best
to obtain it in areas of maximum turbulence or mixing. With-
drawing the sample in the proximity of hydraulic jumps or turbu-
lent areas in sewers or collection systems, for example, enhances
the "representativeness" of the sample. As many petrochemical
and refinery effluents have both settleable and floatable
materials, it is particularly important that these substances
be considered when collecting and analyzing the sample. For
example, the external mixing of quiescent sampling points should
precede the actual withdrawing of the sample in order to
minimize the effects of this separation. In some instances
when the organic concentration of a sample exclusive of floating
oily material is desired, the floating materials in the container
can be skimmed off and the remaining aliquot analyzed for organic
content. -29-
-------
Location of Sampling Stations
There is no specific format for locating sampling stations
although the following criteria influence the site selection:
1. accessibility;
2. flow measuring potential;
3. wastewater streams included at the sampling point; and,
4. degree of wastewater homogeneity in the sampling area.
Moreover, the site selection should be commensurate with the
objectives of the survey; vis, in-plant control and stream segre-
gation, optimal routine of wastewaters with respect to treatment
and discharge to receiving bodies of water, evaluating reuse
potential, etc. Additionally, more intense sampling should be
undertaken in plant areas where concentrated pollutants are
anticipated and where wastewater flow and concentration are
highly fluctuative.
Survey Analytical Information
Once the sampling equipment has been selectee1, the proper
techniques developed, and the locations determined, the necessary
analyses for each sampling station should be tabulated. This
must be done judiciously as too many analyses often overburden
the laboratory and the budget without enhancing the effectiveness
of the survey. Conversely, infrequent or insufficient sampling can
result in data gaps which severely emasculate the overall pollution
control program. It is therefore necessary to outline an analyti-
cal schedule which is consistent with the stated objectives of the
survey. An example of a schedule for a comprehensive sampling
program is shown in Table 7. Although individual industrial
surveys should be modified as required to meet specific condi-
tions, the format shown in Table 7 can be used as a general
guideline.
SAMPLE PRESERVATION
The applicability of the results of any wastewater characteriza-
tion or treatability study is necessarily based on the "representa-
tiveness" of the samples collected. Moreover, the results depend
on the manner in which the samples are preserved during the sampling-
analysis time lag. Unpreserved samples may undergo changes resulting
from chemical reactions, biological activity, and volatilization.
However, even in light of these recognized problems, research has
failed to perfect a universal treatment method, or to formulate a
set of fixed rules applicable to samples of all types (ASTM, 1966).
-30-
-------
TABLE 7
SCHEDULE FOR OBSERVATION. SAMPLE COLLECTION. MEASUREMENT. AND ANALYSIS
Sample
Source
Efflu-
ents
ii
n
i
n
Intake
n
Receiv-
ing
Bottom
Sedi-
ment
Sampling
Station
1
2
2
4
5
6
3
3
7-17
Type
of
Sample
.0
CO
14
o
X
X
Y
X
X
X
X
1 Composite
X
X
X
s-^
f a
o o
71 E
[14 >-*
M
C
1,2
M
1,2
M
3
M
D
CO
Standard
Observatioi
M
W
M
2/M
2/Y
a
W
M
W
W
>
Dissolved
Sulfide - i
W
M
W
Q
Set. Mattel
ml/l/hr
W
4
M
W
W
CO
1-1
F-l
O
CO
tir-l
W -^
3 t>0
co B
W
4
M
W
r-l
>
M
Q
8
M
W
E
/i
M
W
W
M
0^
g-f
Q
w
M
Crease
r-l
00
a
w
w
2/Y
Nitrogen - mg/1 N
z
i
en
O
z
Q
Q
2
1
CM
i
Q
Q
2
1
m
Q
Q
Q
Organic-N
2/M
Q
S3
r-l
CO
4-t
O
H
Q
Q
Phos-
phates
mg/1 P04
cu
JJ
en
o-g
rC 01
U 0
r< rC
0 p.
Q
Q
Total
Phosphate
Q
Q
Toxicity
96-Hour
Bioassay
% Survival
in Waste
(undil. )
M
2/Y
u
o
Temperature
W
W
W
2/M
r-l
Dissolved
Oxygen - mg
W
W
2/M
.
CO
00
Coliform Oi
MPN/100 ml
2/W
2/W
t-i
1°
^
r-i
0
c
01
&
M
Q
M
[ Chromium, n
Q
Q
Q
r-l
00
a
14
01
a.
a.
o
o
Q
Q
Q
r-l
1
»
TJ
CO
0)
r4
Q
E
Q
Q
i-i
00
U
c
1-1
N
Q
Q
Q
1
§
-*
Q
Q
Q
a
01
Undissociat
H2S, mg/1
M
Q
Q
a
Special
Observation
2/Y
C = Continuous Measurement
W = Once Weekly
2/W = Twice Weekly
M = Once Monthly
2/M = Twice Monthly
Q = Once Quarterly
2/Y = Twice Yearly
E = Each Time Runoff or
Discharge Occurs
1 = Monthly log of deposited waste to include data and quantity of disposal.
2 = Monthly log showing data, quantity, and point of disposal for all waste
hauled away.
3 = Estimated average daily flow at time of sampling.
4 = Sampling and analyses required during the rainy season,.
-31-
-------
In general, the most common preservation methods include
acidification, refrigeration without freezing, and freezing.
However, any one of these methods will not maintain a sample in a
static condition for long periods of time. For example, the in-
organic and organic composition of a sample containing microorganisms
may be altered merely as a result of freezing and thawing. The
microorganisms act as "bags" of impermeable membranes until they
are disrupted by freezing and thawing, thus passing their dissolved
materials into solution. Also, biochemical changes such as nitrifi-
cation continue in frozen samples of mixtures of algae and bacteria
at concentrations as low as 5 to 10 mg/1 (Jewell, 1968). The best
overall rule with respect to preservation is to complete the
analyses as soon as possible. Probable errors due to deteriora-
tion of the sample should be designated in reporting the analytical
data.
Several studies have compared the effectiveness of acidification,
refrigeration, and freezing on samples (Paulson, API; Agardy & Kiado,
1966; Jewell, 1968; FWPCA, 1969). Procedures for preserving organic
wastewaters including domestic aqueous wastes are presented in Table 8.
Special care should be exercised when preserving refinery waste-
waters. For example, the characteristic burnt sulfide odor in refinery
wastewater is more intense in an acidified sample than in a frozen
sample (Little, 1967), with the odor of the acidified sample more
characteristic of freshly collected samples. Paulson (1969) reported
that the recognizable odor number of frozen samples was half that of
acidified samples and that considerable difficulties are always en-
countered in attempting to transport frozen samples to the laboratory.
It has also been demonstrated that preservation by freezing and acidi-
fication did not completely inhibit bacterial reproduction as indicated
by bacterial counts.
Where total and dissolved concentrations are to be determined,
emphasis should be placed on the separation technique. Dissolved
material may be considered to be that which passes a 0.45 micron
membrane filter (FWPCA, 1969). When the dissolved concentration is
to be determined, filtration should be carried out as soon as possible
in the field or as soon as it is received in the laboratory. Filtra-
tion of the sample may result in loss of the organics on the container
surfaces or the filter material. Volatile material may be lost if the
sample is filtered under a vacuum. Therefore, care should be exercised
to insure that pollutants are not inadvertantly removed during sample
handling.
Although it is generally agreed that detailed handling and preserva-
tion methods cannot be given for all wastewaters because of widely vary-
ing characteristics, the Federal Water Quality Administration labora-
tories have provided general guidelines for the preservation of samples
for several analyses. The parameter measured, method of preservation,
and maximum holding period are summarized in Table 9.
-32-
-------
TABLE 8
RECOMMENDED STORAGE PROCEDURE
(Agardy and Kiado 1966)
Analysis
Sample Storage
Refrigeration @ 4 C
Frozen
Total Solids
Suspended Solids
Volatile Suspended Solids
COD
BOD
OK
Up To Several Days
Up To Several Days
Up To Several Days
Up To One Day In
Composite Sampling
Systems
OK
NO
NO
OK
Lag Develops,
Must Use Fresh
Sewage Seed
-33-
-------
TABLE 9
SAMPLE PRESERVATION
(FWPCA, 1969)
Parameter
Preservative
Maximum
Holding Period
Acidity-Alkalinity
Biochemical Oxygen Demand
Calcium
Chemical Oxygen Demand
Chloride
Color
Cyanide
Dissolved Oxygen
Fluoride
Hardness
Metals, Total
Metals, Dissolved
Nitrogen, Ammonia
Nitrogen, Kjeldahl
Nitrogen, Nitrate-Nitrite
Oil and Grease
Organic Carbon
PH
Phenolics
Phosphorus
Refrigeration at 4 C 24 hours
Refrigeration at 4 C 6 hours
None Required
2 ml Cone H S0,/liter 7 days
None Required
Refrigeration at 4 C 24 hours
NaOH to pH 10 24 hours
Determine on Site No Holding
None Required
None Required
5 ml Cone HNO.,/liter 6 months
Filtrate: 3 ml 1:1 6 months
HNO-/liter
40 mg HgCl2/liter - 4°C 7 days
40 mg HgCl2/liter - 4°C Unstable
40 mg HgCl2/liter - 4°C 7 days
2 ml Cone H SO /liter - 4°C 7 days
2 ml Cone E^O/liter (pH 2) 7 days
None Available
1.0 g CuS04 + H3PO to 24 hours
PH 4.0 - 4°C
40 mg HgCl2/liter - 4°C 7 days
-34-
-------
TABLE 9 (Cont)
SAMPLE PRESERVATION
Maximum
Parameter Preservative Holding Period
Solids None Available
Specific Conductance None Required
Sulfate Refrigeration at 4°C 7 days
Sulfide 2 ml Zn Acetate/liter 7 days
Threshold Odor Refrigeration i
Turbidity None Available
Threshold Odor Refrigeration at 4°C 24 hours
-35-
-------
ORGANIC ANALYSES - COD, BOD, TOG. TOD
Organic wastewater samples should be collected and stored in glass
bottles or in containers that will not interfere with the analysis of
the parameter of interest, either in a positive or a negative manner,
i.e., interference by the release of organic material to solution or
lidsorption and absorption of organics by container surfaces.
Traces of organic material from glassware or the atmosphere may
cause high, positive errors in the COD analysis. Therefore, care
should be taken to exclude contaminants. Glassware may be conditioned
by running blank procedures to eliminate traces of organic material.
With proper precautions, the COD analysis is accurate at concentrations
as low as 20 mg/1 with a standard deviation of 10 percent of the average,
The loss of volatile materials because of the heat rise upon
addition of the concentrated H SO, should be noted.
In all samples where organic material is being analyzed, it is
essential to complete the analysis as soon as possible. This is
imperative with biologically active material. In cases where it is
not possible to measure the organic carbon within 2 hours, it is
necessary to acidify the samples.
Oil and Grease
Samples should be collected in wide mouth bottles with a volume
of at least one liter. Care should be exercized in handling the
sample in order to prevent loss of oily materials prior to analysis.
Color and Turbidity
These two parameters are closely related. Samples with bio-
logically active material should be analyzed as soon as possible
as both color and turbidity sometimes change with sample age.
Dissolved Oxygen
This analysis must be completed as soon as possible after sampling,
especially when oxygen utilizing chemicals such as ferrous iron or
sulfides are present. If analysis must be postponed, the sample may
be preserved by "fixing" the samples with the first two reagents used
in this test; i..e_. , by addition of the MnSO, and alkalide-azide
reagents. It is recommended that the analysis be completed within
4 to 8 hours after preservation in this manner.
Nitrogen and Phosphorus
It is extremely difficult to retard the nitrogen and phosphorus
cycles by any preservation technique in samples containing organic
material. However, if it is necessary to measure particulate and dis-
solved forms, the first step for preservation would be separation of
particulates in one preserved sample. This will reduce the effect of
-36-
-------
particulates on the parameter of interest during the preservation
period. Analysis of total Kjeldahl nitrogen and phosphorus should
be completed on separate samples. The most effective method of
retarding the rate of conversions in the nitrogen and phosphorus
cycles is by inhibiting the growth of microorganisms by the addi-
tion of 40 mg/1 HgCl (using a one percent solution) and storing
at 4 C. L
Activated Sludge Mixed Liquor
In pilot plant studies of activated sludge, it is desirable to
use a "standardized" activated sludge. However, it is not feasible
to maintain a constant activated sludge culture in a functioning
condition for extended periods of time. Changes in the composition
and activity of the sludge takes place continuously and upsets are
likely to occur. For these reasons, methods of preserving activa-
ted sludge have been evaluated (Buzzell, Thompson, and Ryckman,
1969) . The following preservation methods were tested with regard
to the practicability and the character (washing response appearance)
of the sludge after preservation:
1. Freezing slowly at -15 C (deep-freezer uni:,
2. Freezing quickly at -76 (acetone and dry ice)
3. Freezing quickly at -192 C (liquid nitrogen)
4. Lyophilization
In all cases, lyophilized (freeze-dried) sludge was the most
vigorous, using oxygen at a significantly higher rate than sludges
preserved by the other methods.
The general method of preservation by lyophilization and re-
activation is outlined as follows:
1. The solids are concentrated by centrifuging at 870 G to a
concentration of 80,000 to 100,000 mg/1.
2. The concentrated sludge is quickly frozen in an acetone
dry ice bath at -78 - 2 C, and then attached to a refrigerated
vacuum unit where the water is removed by sublimation over a
period of 24 hours.
3. Before using the sludge, it is necessary to add moisture
to rejuvenate the microorganisms. Moisture is added by mixing a
weighed amount of the dried sludge with synthetic sewage. The
sludge is placed in batch units and fed twice daily. It has been
found that 24 hours of rejuvenation were necessary to obtain
maximum reaction rates.
-37-
-------
Sludge preserved in the manner prescribed above can be stored
in a screw-top bottle, unrefrigerated in the dark for at least 6
months as long as the sample is free of moisture. Sludge in this
form is easily handled and weighed and is reportedly not affected
by hygroscopic moisture during weighing. No problems have been
experienced in re-suspending the dried sludge and its appearance
is very similar to that observed prior to lyophilization.
Before wastewater samples are fed to treatability units or
subjected to most chemical analyses, preservation constraints must
be removed; i.e- , acidified samples neutralized, frozen samples
reactivated, and refrigerated samples warmed to room temperature.
If wastewater temperatures are expected to deviate from room
temperature, apprqpriate adjustment should be made prior to
their use in treatment units.
SAMPLE VOLUME REQUIREMENTS
Wastewater sample volumes depend on the type and number of
determinations to be made and the size and retention time of the
treating unit under investigation. Generally, at least 2 to 3
liters should be collected and an additional liter if all mineral
constituents are to be analyzed. The quantity collected should
include a surplus for verifying analyses and for performing
additional analyses. It is difficult to predict sample require-
ments necessary for the treatability studies since any combination
of physical, chemical and biological treating units may be used.
Approximations of volume requirements for several analyses
are available from ASTM (ASTM, 1966). After these factors are
estimated, it is customary to increase the sample size by a
safety factor to account for underestimates, reruns, and additional
testing which may become necessary after initial investigation.
Confirmatory analyses should be conducted to detect any changes
in the wastewater between sampling and testing, especially where
long hauling distances are involved. Ground transportation is
normally the most economical means of shipping bulk samples and
truck and bus lines offer relatively fast and efficient service
in most areas of the United States. A successful treatability
study is dependent upon several factors, many of which have been
previously discussed; but nothing is more important than perform-
ing all pertinent analyses on representative samples. The con-
junctive use of sample preservation and/or coordinated sample
scheduling are prerequisites for a valid treatability study .
-38-
-------
WASTEWATER CHARACTERIZATION
INTRODUCTION
A comprehensive analytical program for characterizing wastewaters
must be based on relevancy to unit treatment process operations and
effluent quality constraints. It is therefore necessary to consider
these unit processes in terms of the effect specific pollutants have
on their operational effectiveness as well as their process capacity
relative to satisfying effluent quality criteria. Once this has been
accomplished, a characterization schedule consistent with the goals of
the program for identifying and treating refinery and petrochemical
wastewaters can be formulated. The characterization of treatment
processes, but also serves as the basis for delineating contaminated
and uncontaminated streams within a plant, identifying toxic streams,
and indicating streams with reuse or product recovery potential. A
general analytical format for characterizing the organic and inorganic
constituents in wastewaters is illustrated in Figure 8.
PARAMETER APPLICATION FOR THE CHARACTERIZATION OF WASTEWATERS
Parameters used to characterize the liquid and sludge fractions of
petrochemical and refinery wastewaters can be categorized into organic
and inorganic analyses. The organic content of wastewater usually is
estimated in terms of oxygen demand using biochemical oxygen demand (BOD),
chemical oxygen demand (COD) or total oxygen demand (TOD), or in terms of
carbon using total organic carbon (TOC). The interrelationship of these
organic parameters in terms of accuracy (yield in terms of percent of
theoretical oxygen demand or carbon concentration) is shown in Figure 9.
It should be recognized that these parameters do not measure the
same constituents. Specifically, they may be defined as meaning the
following:
BOD - biodegradable organics (in terms of oxygen demand)
COD - organics which can be oxidized chemically and some inorganics
such as sulfides, sulfites, ferrous iron, chlorides, and nitrite.
TOD - all organics and some reduced inorganics (in terms of oxygen)
TOC - all organic carbon (in terms of carbon)
Other organic analyses commonly used in the characterization of
refinery and petrochemical wastewaters include organic acids, alcohols,
aldehydes, phenolics, oils, etc.
The inorganic characterization schedule should include those tests
which provide information concerning:
1, potential toxicity (heavy metals, etc.)
2. potential inhibitors (chlorides, sulfates, etc.)
-39-
-------
LIQUID
FRACTION
GENERAL ANALYSIS
COLOR
TURBIDITY
TEMPERATURE
TOXICITY
TASTE 8 ODOR
OXYGEN
DEMAND
ORGANIC
CARBON
CONCENTRATION
BOD
CALCULATED
ThOO
(THEORETICAL
OXYGEN DEMAND!
COO
(STANDARD
METHODS)
1 TOC |
1
1
1 ,
TOD
(TOTAL OXYGI
DEMAND)
1
COD
(RAPID TEST)
_N
1
T
BOD,.
ANALYSIS FOR MISCELLA-
NEOUS ORGANICS AS RE-
QUIRED
FIGURE 8
CHARACTERIZATION OF LIQUID WASTEWATER
-40-
-------
ORGANIC CARBON
OXYGEN DEMAND
CONCENTRATION
TOC
TOTAL
; ORGANIC
CARBON
Th OC 100%,
^THEORET-'
ICAL
ORGANIC x
^CARBON
-100
ThOD
-50
THEORET-
ICAL
OXYGEN
DEMAND
TOD
TOTAL
OXYGEN
DEMAND
COD
CHEMICAL
OXYGEN
DEMAND
ferANDARD\
METHODS j
! COD
CHEMICAL
OXYGEN
DEMAND
VTEST
BODgp
Nitrification
BIO-
CHEMICAL
OXYGEN
DEMAND
/20-DAY\
INCU-
V BATION /
BOD.
FNitnfica(ion
-------
3. contaminants necessitating specified treatment
(acidity or alkalinity, pH, suspended solids, etc.), and
4. nutrient evaluation (nitrogen and phosphorus)
When considering wastewater characterization, organic and oxygen-
demanding substances are of immediate concern. However, the single
and conjunctive use of many parameters, both organic and inorganic,
may be necessary to provide the proper analysis of a wastewater. A
review and discussion of the aforementioned parameters is included
as follows.
Organic Parameters
Biochemical Oxygen Demand (BOD)
The BOD is an estimate of the amount of oxygen required to
stabilize biodegradable organic materials by a heterogeneous microbial
population. The procedures for performing the BOD test are described
in Standard Methods for the Examination of Water and Wastewater (1965),
The BOD, however, is subject to many variables and constraints, par-
ticularly when considering complex industrial wastes (Eckenfelder
and Ford, 1970). These are discussed as follows.
Time of Incubation
The importance of the incubation time variable is in-
dicated in the basic BOD equation. The usual time is taken as
five days although the time for complete stabilization to occur
(the ultimate BOD) will depend on the nature of the substrate
and the viability of the seed microorganisms. Many substrates
can be substantially degraded in twenty days and the twenty-day
BOD is considered as the ultimate BOD in various applications.
For example, the ultimate oxygen demand in many receiving bodies
of water is predicated on twenty-day values, and the effluent
quality criteria is therefore expressed in terms of twenty-day
BOD. It should be recognized, however, that many organic com-
pounds require longer periods of time before the ulimate oxygen
demand is satisfied biologically. Recently published BOD curves
for tertiary butyl alcohol using acclimated seed indicated that
2 percent of the theoretical yield occurred in 5 days, approxi-
mately 65 percent occurred in 20 days, and the ultimate demand
was satisfied in excess of 30 days (Love, 1970). Assuming these
data are valid, the oxygen requirement for a long-term biological
detention basin receiving substantial quantities of TEA would be
underestimated if based on 5-day or 20-day BOD values. This under-
scores the importance of properly assessing the BOD time variable
with respect to the ultimate oxygen demand.
Nitrification
During the first 5 to 10 days, the oxygen demand is
generally exerted by carbonaceous materials with a second stage
-42-
-------
demand being exerted by nitrogeneous materials. The nitrification
rate constants are much lower than those for carbonaceous destruc-
tion; and, although the 2 reactions may occur simultaneously, the
nitrification demand is not normally conspicuous until the carbon-
aceous demand has been substantially satisfied. A graphic repre-
sentation of these reactions is shown in Figure 10. The measurement
of oxygen demand exerted by the carbonaceous fraction of the waste
can be made in 1 of 2 ways, namely: by retarding nitrification in
the test bottle by the addition of nitrifying inhibitors, or by
allowing nitrification to occur and subtracting its demand from
the overall result.
Temperature and pH
Although most BOD tests are performed at the standard
temperature of 20°C, field conditions often necessitate incubation
at other temperatures requiring correction factors to compensate
for the temperature difference (Schroepfer, 1964). Similarly, a
pH adjustment is required if the acidity or alkalinity of the sample
is sufficient to create a pH outside the range of 6.5 to 8.3 in the
BOD bottle (Eckenfelder and Ford, 1970).
Seed Acclimation
The use of a biological seed which is not properly ac-
climated to the test wastewater is probably the factor most commonly
responsible for erroneous BOD results. A biological seed should be
developed in a continuous or batch laboratory reactor, feeding the
diluted wastewater to the initial microbial seed. The waste compo-
sition is increased to full strength over a period of time; and
once the organic removal or oxygen uptake in the reactor reaches
the maximum level, the seed can be considered as acclimated. The
time required to obtain this acclimation depends on the nature of
the seed and wastewater. For domestic wastewaters or combined
industrial-domestic wastes, the period should be less than 1 week.
However, for wastes containing high concentrations of complex
organic compounds such as those present in refinery or petrochemical
wastes, a period of several weeks may be required.
Toxicity
The presence of toxic materials in a wastewater sample
may have a biotoxic or biostatic effect on seed microorganisms. The
effect is usually evidenced by "sliding" BOD values where the BOD
yield increases with increasing sample dilution. Once there is
the indication of the presence of toxic materials, steps should be
taken to identify and remove the toxicants or use dilution values
above which the BOD yields are consistent.
Chemical Oxygen Demand (COD)
The COD is a measure of the oxygen equivalent of those con-
stituents in a sample which are susceptible to permanganate or
-43-
-------
t
Q
O
00
' '' iTi1"
1st STAGE Y=Lc(l-IO'kif)
(CARBONACEOUS BOD)
0
RAW
WASTE
2nd STAGE
(NITRIFICATION)
10 20 30 40 50 60
NCUBAT10N TIME (days)
FIGURF 10
BIOCHEMICAL OXYGEN DEMAND
-44-
-------
dichromate oxidation in an acid solution. Although it is independent
of many of the variables which affect the BOD test, there are still
factors which influence the COD value of the sample in question.
Generally, one would expect the ultimate BOD of a waste-
water to approach its COD value. There are several factors,
however, which prevent a consistent BOD ult/COD ratio of unity.
These include:
1. Many organic compounds are dichromate or per-
manganate oxidizable but are resistant to
biochemical oxidation.
2. The BOD results may be affected by lack of seed
acclimation, giving erroneously low readings.
3. Certain inorganic substances such as sulfides,
sulfites, thiosulfates, nitrites, and ferrous iron
are oxidized by dichromate, creating an inorganic COD.
4. Chlorides interfere with the COD analysis but pro-
visions have been made to eliminate this interference.
A modification of the COD test as described in Standard
Methods has been applied recently (Jeris, 1967; Foulds and Lunsford,
1968). An aliquot of wastewater sample is added to a dichromate-
acid-silver solution and heated to 165 C using a digestion time of
15 minutes. The sample is then diluted with distilled water and
titrated with ferrous ammonium sulfate. The COD yield using this
approach is approximately 66 percent of the yield using the Standard
Methods approach, the exact amount depending on the complexity and
stability of the organic constituents involved.
Total Organic Carbon (TOG)
Although TOG is a parameter that has been applied in the
field for many years, the advent of the carbon analyzer has pro-
vided a rapid and simple method for determining organic carbon
levels in aqueous samples, enhancing the popularity of TOG as a
fundamental measure of pollution. The organic carbon determina-
tion is free of the many variables inherent in COD or BOD analyses,
with more reliable and reproducible data being the net result
(Eckenfelder and Ford, 1970). The carbon analyzer basically pro-
vides for the complete oxidation of organic materials using an
analyzer flow diagram as illustrated in Figure 11. A carrier gas
conveys the sample through a catalytic combustion tube where the
constituents are oxidized to carbon dioxide and water. The steam
is removed in a condenser and the remaining gas flows through an
infrared analyzer sensitized for carbon dioxide detection. The
system as shown in Figurell includes a high temperature combustion
tube for total carbon analysis and a low temperature tube for in-
organic carbon analysis, the difference taken as total organic
-45-
-------
Flow
Pressure
Regulator
I
C02
Scrubber
Air i
Purification
Unit
Air Combustion
Tube.
Temp.;: I50°C
Low Temperature
Combustion Tube
Injection Port
"A"
Flow J
Meter
Pressure
Regulator
MQuartz Chips
Saturaturated with
85% Phosphoric
Acjd) Condenser
Sample Select Valve
Temp.^ 950°C
Injection Port
"B"
High Temperature
Combustion Tube
Condenser
i i
: : Li^
1 ! I
l ,::::;.
»"'
' '
, i ,
' t
.4
i . :
'. i < ,
i ,
i . ; - ,
1 ' 1 ' '
i 1 !:.-':
^....-..=4
1 J
Recorder
nfrared Analyzer
Filter
FIGURE 11
FLOW DIAGRAM OF MODIFIED CARBON ANALYZER
-46--
-------
carbon. As the analysis time using the carbon analyzer is only
several minutes, the efficacy of using this parameter is apparent,
particularly when a TOG-COD or TOG-BOD correlation can be established.
Tot^al Oxygen Demand (TOD)
Another analyzer has been developed to measure the amount
of oxygen required to combust the impurities in an aqueous sample.
This measurement is achieved by providing a continuous analysis of
the oxygen concentration present in a nitrogen carrier gas. The
oxidizable constituents in the liquid are converted to their
stable oxides in a platinum catalyzed combustion chamber. This
disturbs the oxygen equilibrium at the platinum surface which is
restored by the oxygen in the carrier gas stream. This depletion
is detected by a silver-lead fuel cell and is recorded as a nega-
tive peak related to the oxygen demand of the sample. The TOD
method measures the amount of oxygen consumed in the following
chemical reactions (Clifford, 1967).
TABLE 10
TOTAL OXYGEN DEMAND REACTIONS
Highest StablePercent
Reaction Oxidation State Reaction Efficiency
C + 02 C02 95 - 100
H + %02 H20 95 - 100
N- + %0 NO 95
s-2 , 20 _2
S + ^U2 SO. Z 78
-2 4-2
SO., + kOn SO, 72
32 4
The TOD and TOC analyzers have similar applications, the output data
being correlated to COD and BOD values when possible.
Correlation of Organic Parameters
One of the most effective uses of the aforementioned organic
parameters is to consider them in terms of their interrelationships *
Each of these parameters should be interpreted not only as an array
of individual values, but also as sets of numbers which relate to
each other. This approach alludes to a more interpretative defini-
tion of the nature of organics which is represented by these analyses.
-47-
-------
COD and BOD Relationships
The COD-BOD relationship is generally considered to indicate
the fraction of the chemically oxidizable organics which are amenable
to biological degradation. For example, if the BODult/COD ratio of
a chemical or refinery wastewater approached unity, a major fraction
of the organic materials in the waste would be considered as bio-
degradable. Conversely, a BODuit/COD ratio of 0.1 to 0.3 would
indicate that a major portion of the organics which are amenable to
chemical oxidation are resistant to biochemical oxidation, and a
proposed biological treatment system should be considered as
questionable on this basis. It is, of course, possible that a
large fraction of the observed COD is attributable to the oxida-
tion of reduced inorganic constituents, but this can be determined
by performing ancillary chemical analyses.
Average 6005 and COD values for wastewaters discharged
from chemical plants producing the indicated products are tabulated
in Table 11. More specifically, it is helpful to evaluate the BOD
or COD yields as a portion of the theoretical oxygen demand for
various classes of compounds. The COD and BOD yields with respect
to theoretical oxygen demand (Th OD) for aliphatics, aromatics,
nitrogeneous organics, and refractory organics are presented in
Table 12 (Buzzell, Young and Ryckman, 1968).
COD-BOD/TOC Relationships
In attempting to correlate the COD or BOD of a petrochemical
or refinery wastewater to TOG, certain factors which might constrain
or discredit the correlation should be considered at the outset.
These include:
1. A portion of the COD may be attributable to the
oxidation of inorganics as previously described
while the TOC analysis does not include the
oxidation of these compounds.
2. The BOD or COD tests do not include those organic
compounds which are partially or totally resistant
to chemical or biochemical oxidation. However,
all of the organic carbon is recovered in the
TOC analysis.
3. The BOD test is susceptible to variables which
include seed acclimation, pH, temperature, toxic
substances, etc. The COD and TOC tests are in-
dependent of these variables.
One would expect the stoichiometric COD/TOG ratio of a
wastewater to approximate the molecular ratio of oxygen to carbon
(32/12 = 2.67). Theoretically, the ratio limits would range from
zero, when the organic material is resistant to dichromate oxidation,
-48-
-------
TABLE 11
CHEMICAL WASTE CHARACTERISTICS
Principal Products
Phthalic anhydride, maleic anhydride plaatlclzers, ri2SO4
Chemical warfare gas, chromium plating
Terephthallc acid, isophthellc acid, dimethyl tenaphthalate
Butadiene , styrene , polyethylene , olef Ins
Phenol , ethyl ene
Acrylonitrile
Fatty acids, esters, glycerol
Regenerated cellulose
Acetylene
Dyes, pigments. Inks
Azo & anthraqulnlne dyes
Anthraqulnlne vat dyes
Ethylene, alcohols, phenol
Benzene, ethylene, butyl rubber, butadiene, xylene, isoprene
Acrylonitrile, acetonllrlle, hydrogen cyanide
Terephthalic acid
Glycerine, various glycols
Methyl & ethyl parathlon
Methyl isocyanate, phosgene dlphenol glycine
Urea, ammonia, nitric acid, NH4NO,
Butadiene, styrene, propylene, polyolefin, adipic acid
Butadiene , alkylate , methyl ethyl ketone , styrene , maleic
anhydride
Butadiene, maleic acid, fu merle acid, tetrahydrophthalic
anhydride
Dlphenol carbonate , D-nitro-phenol , benzene , qutnoltn ,
H-3O. tear gas, ditnitro benzole acid
Organo-phosphates, esters, resins, phosphorous chlorides
Phenols
500 different products
Organic & inorganic chemicals
Phenols
Additives for lubricating oils
Polyethylene, ethylene oxide, ethand polypropylene
Aery late s , insecticides , enzymes , formaldehydes , amines
Ethylene, propylene, butadiene, crude benzene, toluene
Acids , formaldehyde , acetone , methanol , ketone s , nitric acid ,
nylon salt, vinyl acetate acetaldehyde
Isocyanates , polyols, urethane foarp
Acetaldehyde
Acrylanltrile, phenol, butadiene
ethylene, propylene, toluene xylene
Acids, formaldehyde, acetone, methanol, ketones, alcohols,
acetaldehyde
Petrochemicals
polystrene
y
Pharmaceuticals (Dallas WPCF 661
Organic chemicals
2, 4, 5-1
2-4-Li
Butadiene
Organic chemicals
Oletins
Adipic acid
Hexamethylenediamirie
Pctro chemicals
Petro chemicals
0
(mod)
0.002
0.001
5.36
1.68
2.0
0.302
0.10
1.41
0.452
0.94
S.O
5.9
14.7
3.9
0.335
U.49
0.075
0.543
0.65
1.38
2.0
3.605
0.098
1.2
0.215
3.2
2.1
0.22
0.20
2.1
1.06
0.228
3.46
0.57
1.15
1.817
0.43
1.15
15.2
0.085
0.750
1.4
0.037
0.077
0.005
0.005
0.288
0.288
0.238
0.13
0.13
0.02
0.17
BOD5
taa/1)
200
300
10.000
227
352
30U
1700
91
390
2810
3100
1146
105
5630
1870
959
650
845
6600
360
100
6600
465
1385
1960
500
530
421
20,000
1300
15,000
177
200
15,5
2000
14,000
850
15,000
15,000
24,000
COD
(mo/1)
200
1100
9600
1200
1200
14,000
1760
1160
3600
273
830
4160
5000
3420
140
1230
1525
1380
2040
13,200
500
13,200
1050
2842
2660
10,130
1200
50,000
23,100
1500
30,000
380
4800
1700
21,000
23,000
350
750
320
35,000
113,000
40,000
33,000
ss
tog/1)
24
10,600
300
239
93
152
610
' 106
80
225
10
322
673
250
80
160
50
200
60
120
900
500
300
700
3J8
300
120
400
ISO
1200
30
-49-
-------
TABLE 12
EVALUATION OF COD AND BOD WITH RESPECT TO THEORETICAL OXYGEN DEMAND - TEST ORGANIC CHEMICALS
Chemical Group
COD
(mg/mg)
Measured COD
(mg/mg)
Measured BOD5
(mg/mg)
BODr
ALIPHATICS
Methanol
Ethanol
Ethylene glycol
Isopropanol
Maleic acid
Acetone
Methyl ethyl ketone
Ethyl acetate
Oxalic acid
AROMATICS
Toluene
Benzaldehyde
Benzoic acid
Hydroquinone
o - Cresol
NITROGENOUS ORGANICS
Monoethanolamine
Acrylonitrile
Aniline
REFRACTORY
Tertiary - butanol
Diethylene glycol
Pyridine
1.50
2.08
1.26
2.39
0.83
2.20
2.44
1.82
0.18
Group Average
3.13
2.42
1.96
1.89
2.52
Group Average
2.49
3.17
3.18
Group Average
2.59
1.51
3.13
1.05
2.11
1.21
2.12
0.80
2.07
2.20
1.54
0.18
1.41
1.98
1.95
1.83
2.38
1.27
1.39
2.34
2.18
1.06
0.05
70
100
96
89
96
94
90
85
100
91
45
80
100
100
95
84
51
44
74
58
84
70
2
1.12
1.58
0.36
0.16
0.64
0.81
1.81
1.24
0.16
0.86
1.62
1.45
1.00
1.76
0.83
nil
1.42
0
0.15
0.06
75
76
29
7
77
37
74
68
89
56
28
67
74
S3
70
58
34
0
44
26
0
10
T
u
Group Average
52
-50-
-------
to 5.33 for methane. Higher ratio values indicate the presence of
inroganic-reducing agents. Reported BOD, COD, and TOG values for
several chemical and refinery wastewaters are listed in Table 13,
the COD/TOG ratio varying from 2.19 to 6.65 (Eckenfelder and Ford,
1970).
The variability between the calculated and measured COD/TOG
values for selected organic compounds is shown in Table 14. This
variability is attributed to the COD yield, and waste streams con-
taining a portion of these substances would be subjected to a fluc-
tuating COD/TOC ratio in the event of relative concentration changes.
The greater the variability in the characteristics of an industrial
waste stream, the more pronounced will be the change in its COD/TOC
ratio. This in itself is a good indicator of the degree of consis-
tency of wastewater constituents and can be a valuable aid in
predicting the design organic load applied to a biological treat-
ment facility.
COD/TOD Relationship
The COD and TOD values have been correlated for several
waste streams, although extensive correlation data from refinery
and petrochemical streams is not presently available. The TOD
concentration usually can be expected to be higher than the cor-
responding COD values by virtue of the fact that chemical oxida-
tion is less efficient than that obtained in the catalyzed
combustion chamber of the TOD analyzer. Results of TOD analyses
for a number of different compounds, for example, indicated that
the measured total oxygen demand was usually closer to the
theoretical demand values than those obtained using chemical
methods (Goldstein, 1968). Preliminary unpublished data indicate
that the COD yield of refinery wastewaters ranges from 70 to 84
percent of the total oxygen demand. Unusually high COD/TOD ratios
would indicate either that most of the organics oxidized in the TOD
analyzer are susceptible to chemical oxidation or that conditions
favor the chemical oxidation of inorganics over their oxidation
in a catalytic combustion chamber. If the COD/TOD value was un-
usually low, then the presence of constituents resistant to
chemical oxidation would be inferred, or perhaps a more com-
plete oxidation of inorganics in the combustion tube was observed
than that obtained chemically. Reported COD/TOD values for un-
treated industrial wastewaters are tabulated in Table 15 (Ford,
Eller and Gloyna, 1970; Wood, Perry and Hitchcock, 1970). These
data indicate that average COD/TOD values for the raw industrial
wastewaters cited approximate unity, with the variation being
attributed to factors previously mentioned.
Correlation with Chemical and Refinery Data
Recent studies have provided BOD, COD, and TOG data for
chemical and refinery process wastewaters discharged from
-51-
-------
TABLE 13
INDUSTRIAL WASTE OXYGEN DEMAND AND ORGANIC CARBON
Type of Waste
Chemical*
Chemical*
Chemical*
Refinery
Refinery
Chemical
Chemical
Chemical-Refinery
Petrochemical
Chemical
Chemical
Chemical
Chemical
Chemical
Chemical
Chemical
Petrochemical
Olefin Processing
Butadiene Processing
Chemical
BOD COD
(mg/1) (mg/1)
4,260
2,440
2,690
226
257
576
24,000 41,300
580
3,340
850 1,900
700 1,400
8,000 17,500
60,700 78,000
62,000 143,000
165,000
9,700 15,000
-
-
359
350,000
TOG
(mg/1)
640
370
420
45
51
122
9,500
160
900
580
450
5,800
26,000
48,140
58,000
5,500
-
133
156
160,000
BOD/TOG COD/TOG
6.65
6.60
6.40
1.30 5.00
1.20 5.00
4.72
2.53 4.35
3.62
3.32
1.47 3.28
1.55 3.12
1.38 3.02
2.34 3.00
1.28 2.96
2.84
1.76 2.72
2.70
2.40
2.30
2.19
High Concentration of Sulfides and Thiosulfates
-52-
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TABLE 14
COD/TOC RELATIONSHIPS
Substance
Acetone
Ethanol
Phenol
Benzene
Pyridine
Salicylic Acid
Methanol
Benzoic Acid
Sucrose
COD/TOC
(Calculated)
3.56
4.00
3.12
3.34
3.33
2.86
4,00
2.86
2.67
COD/TOC
(Measured)
2.44
3.35
2.96
0.84
nil
2.83
3.89
2.90
2.44
-53-
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TABLE 15
COD/TOD RATIOS FOR UNTREATED INDUSTRIAL WASTEWATERS
Type of Wastewater COD/TOD
Refinery Waste 0.99
Pesticide Manufacturing Waste 0.95
Petrochemical Waste 0.98
Petrochemical Waste 1.20
Petrochemical Waste 1.12
Plastics Manufacturing Waste 1.25
Cyrogenics Plant Waste 1.04
Refinery Waste 0.71
Combined Refinery-Petrochemical Waste 0.75
-54-
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various plants (Ford, Eller, and Gloyna, 1970). These analyses
were performed daily for a period of several months. The mean
values of the array of organic parameters for each industry are
plotted in Figure 12, and suggest a general correlation within
the concentration limits as shown.
Assuming a linear relationship does exist, variances from
the regression line can be attributed to two sources, namely:
diversity in wastewater constituents and analytical error. The
analytical error is less significant when the dissolved organics
are concentrated and highly variable and one would consequently
expect the best correlation. However, a diversity in wastewater
constituents resulting from in-plant process changes or batch-
type operations generally would adversely affect the degree of
fit or correlation coefficient. The average organic ratio values
observed within each industry and the 95 percent confidence limits
are tabulated in Table 16. These data reflect the statistical
variations of the parametric ratios only and not the absolute
values of the individual BOD, COD, and TOG analyses.
Additionally, the coefficient of variance and the correlation
coefficient for the array of parametric ratios observed within
each industry is cited in Table 16. The correlation coefficient,
which is a measure of the linear covariation of the variables,
was used to establish the relative linearity of the parametric
ratios between industries. The 95 percent confidence limits of
these values can be approximated knowing the number of observa-
tions and assuming a normal distribution for each organic
parameter.
The following conclusions are based on the values cited in
Table 16:
1. Based on a knowledge of the wastewater characteristics
and production schedule for each of the industries'
studies, the probability of developing a useful cor-
relation between the organic parameters is best when
the variation in wastewater concentration is high and
the product diversity is low. When this is not the
case, there may be no useful correlation.
2. The relationship between these parameters is
generally linear and can best be characterized
by a least square regression line with the degree
of fit expressed by the correlation coefficient
and 95 percent confidence limits. The direct ratio
of these parameters is most applicable when the
regression line converges toward the origin. An
intercept on either axis would necessitate the
ratio being expressed by a linear equation in the
form of Y = mX + b.
-55-
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AVERAGE TOC (mg/l)
10,000
1,000
o
o
o
LiJ
O
a: 100
10
10 100 1000 10,000
AVERAGE BOD5 (mg/l)
10,000
1,000
O
O
CD
100
10
I I I I I
I I I I I I 11
10 100 1,000 10,000
AVERAGE TOC (mg/l)
FIGURE 12
CORRELATION OF ORGANIC
PARAMETERS (MEAN VALUES )
(FORD, et al 1970)
-56-
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TABLE 16
STATISTICAL ANALYSIS
Wastewaters
Refinery
Refinery
Chemical
Chemical
Chemical
Chemical
Chemical
Chemical
Composite
95 7. CONFIDENCE LIMITS
BOD/COD
0.31 - 0.24
0.24 - 0.12
0.50 - 0.30
0.39 - 0.23
0.45 - 0.22
0.48 - 0.36
0.56 - 0.30
0.59 - 0.28
0.47 - 0.06
BOD/TOC | TOC/COD
I
1.82 - 0.20 0.22 - 0.18
1.76 - 2.20 0.18 - 0.28
1.59 - 1.06 0.32 - 0.12
1.54 - 0.62 0.28 - 0.12
1.49 - 0.68 0.31 - 0.14
2.08 - 1.30 0.25 - 0.12
1.91 - 1.84 0.27 - 0,16
1.40 - 0.44 0.41 - 0.28
Coefficient of Variation
BOD/COD BOD/TOC TOC/COD
0.39 0.05 0.41
0.25 0.62 0.78
0.30 0.33 0,19
0.29 0.20 0.21
0.24 0.23 0.14
0.38 0.31 0.24
0.27 0.48 0.30
Correlation
BOD/
COD
0.38
0.58
0.64
0.49
0.6C
0.6f
0.97
0.23 0.16 0.34 ! 0.67
1.67 - 0.38 0.28 - 0.06 ' 0.06 0.11 0.06 1 0.69
; ;
#
OBS
20
9
16
13
21
20
17
20
6
BOD^
TOC
0.39
0.4*
0.51
0.21
0.7f
0.9(
0.89
o.ie
0.4(
Coefficient
#
OBS
17
7
16
12
20
16
12
18
5
TOC/
COD
0.09
0.41
0.62
0.86
0.50
0.72
0.89
0.34
0.72
E
ff
DBS.
34
10
16
13
20
20
12
20
6
-57-
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3. The correlation of COD to TOC was better than BOD
to TOC or BOD to COD in most of the cases studied.
Once a correlation of the organic parameters is established
for a given wastewater, it should be periodically verified since
even a slight process modification or operational change can
significantly affect these parametric interrelationships.
Although subject to the aforementioned exceptions, the ultimate
BOD of a wastewater is generally assumed to approximate its COD.
Therefore, if the observed BOD/COD values of a waste stream are
consistently low, i.e., less than 0.3 to 0.5, then the applicability
of biological treatment is conjectural. This precept has been con-
firmed by a series of bench scale simulation studies using biological
methods to treat refinery and chemical wastewaters. Representative
wastewater samples were pumped to continuous biological reactors,
varying the organic loading rate (Ibs BOD applied per day per pound
mixed liquor volatile suspended solids) in order to determine the
optimal loading and dilution requirements. A generalized relation-
ship between the influent BOD/COD ratio and the maximum organic
loading allowing 90 percent or better BOD removal was observed.
These data are plotted in Figure 13. The one exception to this
trend was a wastewater containing a phenolic concentration in
excess of 125 mg/1. Although this concentration would be diluted
to its sub-inhibitory level in the BOD bottle, the stress of phenolic
application inherent with higher organic loadings in this case would
exert a deleterious effect on the biological population in the reactor.
This would have a net effect of decreasing the BOD removal efficiency
in the reactor, illustrating the significance of the presence of in-
hibitory or toxicological substances as well as their concentration.
Although attempts to use this approach of applying BOD and TOC
data were unsuccessful, it is postulated that BOD and TOD data
similarly plotted would indicate the same trend.
A different representation of the data is shown in Figure 14,
plotting the COD and TOC removal in the biological reactor at a
constant organic loading as a function of the influent BOD/COD
and BOD/TOC ratios, respectively. It is noted that the COD removal
in Figure 14 is greater in all cases than the idealized removal
relationship (BOD removal = COD removed). Although this is par-
tially attributable to the BOD - BOD relationship, it is also
indicative of the ability of the microorganisms to better absorb,
assimilate, and degrade organic materials in a fluidized biological
system than in the BOD bottle, assuming the absence of inhibitory
substances in both.
Similarly, the TOC removal in Figure 14 is generally greater
than the idealized removal based on the influent BOD /TOC ratio.
The exceptions possibly can be attributed to the fact that either
the BOD,, yield of the raw wastewater is abnormally low due to seed
-58-
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o 0.6
§ °-4
O
O
o.2
I30mg/l PHENOL
0.2 0.4 0.6 0.8 1.0
LOADING TO ACHIEVE 90% OR BETTER
BOD5 REMOVAL (Ibs BOD/ Ib MLVSS day)
1.2
FIGURE 13
EFFECT OF BOD--COD RATIO ON TREATABILITY
(Ford, et al 1970)
-59-
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I0°
>s
3)8 80
Zl
gg
8°
z
-------
acclimation, environmental factors, etc., or the TOG yield is too
high due to the inclusion of inorganic carbon, or both. Additional-
ly, there is the possibility that a substance is inhibitory in the
biological reactor but not in the BOD bottle. The dashed lines as
shown in Figures 13 and 14 indicate the data groupings and do not
represent statistically analyzed limits.
In summary, it can be stated that TOG and TOD are both valid
measures of pollution and both can be correlated to COD values in
many applications. They are excellent control parameters because
of the abbreviated analysis time associated with the analyzers. It
is unlikely that COD, TOG, or TOD can be correlated to BOD unless
the concentration and nature of constituents in the wastewater re-
main relatively unchanged. However, the conjunctive use of these
parameters in terms of BOD, COD, TOC, and TOD ratios is an effective
and logical approach in properly characterizing the organic component
of an industrial wastewater.
Other Organic Parameters
Oil and Grease
One of the more important parameters applied in characterizing
refinery and petrochemical wastewaters is the oil and grease measurement.
This is particularly true since oils have both a recovery value and
create problems in treatment unit processes. Therefore, oil separation
and recovery facilities are required for all oily wastewater streams.
Extraction techniques using various organic solvents, such as
n-hexane, petroleum ether, chloroform, and trichloro-trifluoro-ethane
are used to evaluate the oil and grease content of wastewaters. The
method outlined by the EPA measures hexane extractable matter from
wastewaters but excludes hydrocarbons that volatilize at temperatures
below 80°C ("FWPCA Methods for Chemical Analysis of Water and Wastes,"
1969). Additionally, not all emulsifying oils are measured using these
extraction techniques. However; a modified procedure provides for the
release of water-soluble oils by saturating the acidified sample with
salt followed by isolation on the filter in the accepted manner (Taras
and Blum, 1968).
Phenolic Compounds
Phenols and related compounds are generally prevalent in
refinery and petrochemical wastewaters and are of particular signifi-
cance as they are potentially toxic to marine life, create an oxygen
demand in receiving waters, and impart a taste to drinking water with
even minute concentrations of their chlorinated derivatives. Primary
sources of phenolics are in wastewaters from benzene refining plants,
oil refineries, coke plants, chemical operations, and plants which
are processing phenols to plastics.
-61-
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Phenols, or the hydroxy derivatives of benzene, are measured
using the distillation approach as per Standard Methods (1965) or by
other miscellaneous colorimetric, spectroscopic, or chromatographic
techniques (Simard, 1951; Schmauch and Grubb, 1954; Payn, 1960). A
rapid, precise, and selective method using ultraviolet differential
adsorption also has been recently reported (Martin, 1967).
Miscellaneous Techniques
There are a multiplicity of other techniques used to identify
organic materials in wastewaters other than those previously described.
Such techniques are deployed as required to identify specific organics
and to monitor their fate through various treatment systems. Gravi-
metric and volumetric analyses, mass spectrometry, and infrared spec-
troscopy are classified as the more popular techniques used to
characterize refinery and petrochemical wastewaters; while carbon ad-
sorption, liquid-liquid extraction, and gas chromatography often have
been used to identify petroleum products in conjunction with pollution-
related instances.
Inorganic Parameters
There are many inorganic parameters which are pertinent when de-
termining potential toxicity, general characterization, or process
response. Although the evaluation of any number of inorganic analyses
may be required for a particular situation, some of the more prevalent
analyses are considered herein (Eckenfelder and Ford, 1970).
Acidity
The acidity of a wastewater, or its capacity to donate protons,
is important because a neutral or near-neutral water is required before
biological treatment can be deemed effective, and many regulatory
authorities have criteria which establish strick pH limits to final
discharges. Acidity is attributable to the unionized portions of
weak ionizing acids, hydrolizing salts, and free mineral acids. The
latter is probably the most significant as it is difficult to predict
neutralization requirements when mineral acidity prevails. Microbial
systems may reduce acidity in some instances through biological
degradation of organic acids.
Alkalinity
Alkalinity, or the ability of a wastewater to accept protons,
is significant in the same general sense as acidity, although the
biological degradation process does offer some buffer capacity by
furnishing carbon dioxide as a degradation end-product to the system.
It has been estimated that approximately 0.5 pounds of alkalinity
(as CaCO ) is neutralized per pound of BOD removed.
-62-
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Dissolved Solids
The dissolved solids can have a pronounced deleterious effect
on many unit processes included in the waste treatment system. The
limiting dissolved salts concentration for effective biological treat-
ment, for example, is approximately 16,000 mg/1. Chloride concentrations
of 8,000 to 10,000 mg/1 (as Cl") have also been reported to adversely
affect biological systems.
Ammonia Nitrogen and Sulfides
Ammonia nitrogen is present in many natural waters in relatively
low concentrations (100 mg/1), although industrial streams often contain
exceedingly high concentrations. The presence of ammonia nitrogen in
excess of 1,600 mg/1 has proved to be inhibitory to many microorganisms
present in a biological aeration basin. Sulfides are present in many
wastewaters either as a mixture of HS~-H S (depending on pH), sulfonated
organic compounds, or metallic sulfides. Although odors can be caused
by the presence of sulfides in concentrations of less than a few hun-
dredths of a mg/1, no inhibitory or biotoxic effects to bacteria are
noticed up to concentrations of 100 mg/1 (as S ). It should be noted,
however, that algal species are adversely affected with sulfide concen-
trations of 7 to 10 mg/1 (Espino and Gloyna, 1967).
Heavy Metals
The influence of heavy metals on biological unit processes has
been the subject of many investigations. Toxic thresholds for Cu, Zn,
Cd, etc., have been established at approximately one mg/1, although
higher concentrations have been noted to have no effect on process
efficiency. For example, zinc concentrations exceeding 10 mg/1 had no
adverse effect on a biological system treating a petrochemical waste.
Several techniques for heavy metal analysis are given in
Standard Methods (1965), although atomic absorption flame photometry
is an effective and rapid method for determining small quantities of
metals. This method is based on the measurement of a light absorbed
at a given wave length by the unexcited atoms of the element being
analyzed.
SUMMARY
From this discussion, it is apparent that the nature and charac-
teristics of the soluble fraction of the wastewater must be evaluated
with respect to the unit processes considered. When one speaks of
pollution, organic and oxygen-demanding substances are of immediate
concern. However, the single or conjunctive use of many parameters,
both organic and inorganic, may be necessary to provide the proper
analysis of a wastewater.
-63-
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IN-PLANT CONSIDERATIONS
The most effective control of wastewaters can be exercised
at or near the site of origin, Wastewater control programs
are implemented through the use of educational programs for plant
personnel, waste elimination during research and development, and
installation of waste segregation devices at the source.
Evaluation of in-plant wastewater control measures may be
developed in four steps:
1. A wastewater survey, including complete quality charac-
terization and flow measurements,
2.. Treatability studies for segregated and combined waste
streams, and
3, The recycle or recovery potential of each waste stream
based on characterization data and process requirements.
The most effective refinery or petrochemical wastewater
collection system incorporates the segregation of waste streams.
This may be ideally accomplished by providing separate collection
systems for the following streams:
1. "clean" water containing cooling tower and boiler blow-
down,
2. highly contaminated process wastes including spills,
batch dumps, etc,
3. oily water,
4. non-oily water,
5. contaminated storm runoff,
6. uncontaminated storm runoff
7. sanitary sewers.
The aforementioned categorization of wastewaters permits a
rapid assay of potential problems and an evaluation of the effective-
ness of in-plant modifications and stream separation, Both
refineries and petrochemical plants produce two general types of
wastewater: large flows with little contamination; and small,
highly contaminated flows. Various uses of raw and reused water
in the crude oil refining industry are illustrated in Figure 15.
Only about 3 percent of the total water used comes in contact with
the product as compared to more than 90 percent that is used for
cooling which is less likely to be contaminated.
-64-
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PROCESS CQNOENSATE &
ONCE THROUGH 0,6%
AIR COOLIMG
STEAM COMPENSATE
0.7%
PROCESSING
0.8 %
STEAM
0.9 %
COOLtNG TOWERS
7U%
LEGEND
RAW WATER
REUSE WATER
FIGURE 15
WATER USE IX REFINERIES
(API, 1968)
-65-
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REFINERY WASTE PROBLEMS
Despite the increase of more than 100 percent processing
capacity experienced by the petroleum refining industry during the
last 20 years (Elkin and Austin 1965), the freshwater requirements
and net pollution load per barrel of crude oil processed has
steadily decreased. However, refineries have many sources of
wastewaters. Problem wastes which are common in almost all
petroleum refineries include spent caustic solutions, sulfide
waters, phenols, and oils.
Spent Caustic
Spent caustic solutions from petroleum refineries contain
sulfides, mercaptides, sulfates, sulfonates, phenolates, naph-
thenates, and other organic and inorganic compounds. Methods
of treatment include chemical, physical, and biological. Direct
disposal into deep wells, thermal incineration, or marketing of
wastes has been practiced but the success of these methods has
normally been limited to concentrated waste streams.
Chemical treatment methods such as regeneration, air oxida-
tion, and neutralization can be utilized for minimizing spent
solution waste discharges. Refinery spent caustic solutions can
contain up to 45 percent by volume of acid oils. Separation of
acid oils (either phenolic or naphthenic) by neutralization of
spent caustic solutions represents one method of treating highly
contaminated effluents to a salable end-product.
Reaction water from the springing of phenolic acid oils con-
tains between 10,000 to 15,000 mg/1 of dissolved phenolics. Strip-
ping and extraction processes can reduce the phenolics in waste-
waters to a level ranging from 100-600 mg/1.
Direct biological treatment of spent solutions is usually
not applicable because of high oxygen demand, low pH, and the
presence of taste and odor-causing compounds. However, the ap-
plication of biological treatment methods following extensive
pretreatment may be successful, although the economics of such
a treatment system should be carefully compared to process
alternatives.
Spent gulfuric Acid
Extensive use of sulfuric acid as a treating agent and as
a catalyst results in acid sludges and acid disposal problems.
-66-
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Most refineries arrange for their acid suppliers to accept
spent sulfuric acid products for recovery or reprocessing.
Recovered spent sulfuric acid products, for example, have been
used to produce fertilizer grade ammonium sulfate.
Sulfide Waste Streams
Hydrocracking of feedstocks containing a large percentage of
sulfur and nitrogen, typical of Middle East, Venezuelan, and
Californian crudes,results in the production of waters containing
ammonium sulfide. Extraction and separation of ammonium and
hydrogen sulfide from such crudes not only is a necessary process
requirement but also results in salable products and decreased
water requirements.
Cooling Tower Slowdown
The greatest quantity of water required in the refining process
is used for cooling purposes as shown in Figure 15. Recycle ratios
vary between 1 and 30, with the average approximating 3 (Petro-
leum Industry Refinery Waste Reuse Survey,1968). The quality of
cooling water depends upon evaporation and contamination from
accidental and intentional additions. This includes the leakage
of hydrocarbons from condenser tubes and coolers, chromate or
phosphate inhibitor additives, and the accidental commingling of
blowdown streams with organic process streams.
PETROCHEMICAL WASTE PROBLEMS
Because of the diversity of products, it is difficult to
generalize regarding the reuse of petrochemical wastewaters. The
American Petroleum Institute's Manual on Disposal of Refinery
Wastes (1969) summarizes the treatment processes presently used
to treat 80 different organic chemicals, 20 inorganic chemicals,
and 11 overall plant wastes. Wastewater characteristics associated
with some chemical products have been recently summarized (Gloyna
and Ford ,1969; Rice,1969). All of these chemical waste streams
present serious problems whenever the COD exceeds 1,000 mg/1, or
when phenols or heavy metals exceed toxic levels. The concentration
of various pollutants that interfere with the efficient operation
of biological treatment processes has been previously documented
(Manual of Refinery Wastes, 1969; Eckenfelder and Ford, 1970).
The quality of wastewater from the petrochemical manufacturing
processes depends on the type of petroleum feedstock, products
manufactured, in-plant control, maintenance, and types of processing
equipment.
-67-
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The major source of low contaminated water in petrochemical
industries is the cooling water and steam equipment. The total
volume of this water will amount to 10 to 80 percent of the total
wastewater and its degree of contamination depends on the following
factors:
1. process leaks,
2. water treatment additives,
3. input from air scrubbing, and
4. blowdown and condensates.
These waste streams have a high potential for reuse, but their
degree of contamination must be considered.
By-Product Disposal in Refineries
The present trend towards integration of refineries and petro-
chemical plants into joint operations located within a single
complex may result in minimizing many of the existing wastewater
disposal problems. This consolidation is occurring because of the
dependency of petrochemical production upon petroleum derivatives,
the increasing percentages of chemicals produced at consolidated
facilities, and the number of separate refineries that now produce
chemicals.
Present trends favor crude oil as a convenient low-cost
feedstock for the manufacture of chemicals. It is noteworthy
that by-products from chemical manufacturing operations are con-
sumed within the conventional oil refinery framework. These
recycles include propylene, butylenes, naptha and gas oil, and
gases from the thermal cracking and needle coking operations, non-
normal paraffins from the detergent paraffin separation unit, and
heavier aromatics from the separation of benzene, toluene, and
xylenes.
The ability to consolidate petroleum refining and petro-
chemical processing in terms of by-product utilization will
stimulate growth towards integrated facilities and assist in
solving pollution control problems. The potential for continued
interest in the concept of integrating chemical industries within
refineries is illustrated in Figure 16. The economic ability
of a refinery to incorporate chemical production is a function of
the size of the base refinery (Beavon, Chute, and Lupfer,1969).
-68-
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IVJVJ
c/5
UJ
% TOTAL REFINER
_ M 0<
-> Ui O
( PETROLEUM COKE ^
, SULFUR ^
, BENZENE. TOLUENE. 8 MIXED XYLENES ^
PARAXYLENE ^
.ETHYLBENZENE 8 ORTHOXYLENE
__ r~
1
PROPYLENE
.PHENOL.
i
1
^m ^m mm mm mm mm§ mmi mm mm mm *
CUMENE. DETERGENT PARAFf
AMMONIA a STYRENE »
ETHYLENE. BUTADIENE 8 AC^
.ACETYLENE 8 CYCLONE
i i i
INS
'LO.
(ENE
0 25 50 75 100 125 150 175
REFINERY CRUDE CAPACITY, MBPD
200
FIGURE 16
MINIMUM REFINERY CAPACITIES FOR
ECONOMIC CHEMICAL MANUFACTURE VERSUS
CAPACITY OF U.S. REFINERIES
-69-
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Nearly 50 percent of all United States refineries have the
capability of economically producing the 10 major petrochemicals.
A classification of United States refineries by capacity is
also given in Figure 16.
REUSE POTENTIAL
A recent survey indicates that the refinery industry reuses
more of its effluent than any other industry (API,1968). Of the
total water used in processing crude oil, only 20 percent is
obtained from natural sources. By means of internal cooling,
the petroleum industry is reusing 80 percent of the water required
for processing each barrel of crude. The trend toward reuse is
attributable to economic incentive as well as anti-pollution legislation.
In light of present and forecasted water quality standards,
consideration of reusing wastewater should be balanced against
the effects of discarding the effluent. When considering economics,
the following factors should favor reuse (Koenig,1967):
1. The value of water.
2. Possible pollution damage.
3. The loss of process material.
4. Effluent quality requirements are more stringent than
those of the raw water supply.
5. Effluent quality requirements are more stringent than
those acceptable for reuse water.
In many areas the costs of treating wastewaters are competi-
tive with freshwater costs. Many factors must be considered
before definitive decisions can be made regarding treatment processes
and direct disposal. Koenig (1967) made the following general
conclusions based on previous cost analysis regarding treatment
processes and direct disposal.
Inorganic Pollutants:
1. Water disposal by spreading at the site is cheaper than
any reuse process.
2. For less than 30,000 gal/day, the cost of removing 500
ppm TDS is comparable to injecting to a depth of 12,000
feet or transferring 500 miles by pipeline.
-70-
-------
Organic Pollutants:
1. Oxidation ponds are cheaper than any reuse or disposal
process including any other means of disposal other than
spreading at the site,
2. Coagulation, sedimentation, and filtration costs are
comparable to transporting effluent five miles for
disposal.
A major consideration where reuse is implemented is the ul-
timate disposal of the concentrated effluent from a waste treatment
unit. For example, waste solutions from ion exchange units will
contain more inorganic salts in a smaller volume than did the
process water. Complete elimination of all wastewater effluents
may result from evaporation using waste heat or product recovery.
The advantages of a "closedloop" or total reuse are significant
when considering the costs of treatment and monitoring needed
to obtain disposal permits from regulatory agencies.
Another method of effectively eliminating effluents may be
possible by establishing a cooperative closed cycle with local
government; and in cases where the growth of industry or the
establishment of new industry is limited by a freshwater supply,
the use of an effluent from a municipal sewage plant may become
very favorable. Except for aesthetics, the quality of effluent
discharged from properly operated municipal waste treatment
facilities is acceptable for many industrial purposes. An
arrangement where a municipality accepts and treats an industry's
wastewaters and subsequently returns the effluent offers economic
incentives and a significant reduction of wastewater discharges.
ESTABLISHING A REUSE SYSTEM
Complete treatment of refinery effluents by physical, chemical,
and biological treatment processes is possible (McPhee and Smith,
1961), although this treatment is usually both expensive and
problematic. Nevertheless, water reuse should be incorporated
into existing plants and made an integral part of proposed plants.
Educational Programs
The establishment of educational programs for employees which
will inform and describe their role in pollution control can often
result in the reduction of the organic pollutants in the final
effluent. Opportunities for wastewater reduction through procedural
changes, elimination of leakage and spills, and improved housekeeping
-71-
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should be emphasized. Communication programs using plant bulletin
boards, articles in the plant paper, and meetings with the person-
nel involved with particular problems can be effective. Elimina-
tion of a pollutant at its source should be emphasized as being
more economical and effective than terminal treatment. The effec-
tiveness of an extensive long-term educational program instituted
by Union Carbide Corporation is reflected in Figure 17 The 36
percent improvement in effluent quality between 1960 and 1961
in part can be attributed to the inception of an educational
program (Rosegarten,1967). The total reduction shown in this
Figure resulted from a comprehensive increase in treatment facili-
ties as well as a continuance of employee educational activities.
This decrease in pollution was achieved in light of a three-fold
increase in plant production.
Accidental Spill and Drip Prevention
A typical material balance in most refineries would show a
three percent loss in crude oil to the sewer (Forbes and Witt,
1965). This loss of product can be partially prevented by the
installation of an extensive piping system called a "drip system"
(Gloyna, Ford, and Eller. 1969). This system includes the place-
ment of pans under all pumps to catch stuffing box leaks, funnels
under all sample cocks to catch drips, and overflow pipes on all
vessels to catch lost product. The resulting wastes from these
devices are segregated for separate disposal or reinjected into
the processing units.
Segregation and Collection of Runoff
Storm runoff can be a significant source of pollution,
depending on the quantity of precepitation and the degree of
runoff contact with process products. Effective utilization of
dikes to collect spills and rain water, separation of runoff
waters, and return of collected runoff waters to process or
cooling towers provides a solution to runoff wastewater problems.
In order to segregate highly contaminated waters, all process
areas should be diked or provided with concrete slabs and curbs.
The storage provided in the dike system will depend on the rainfall
characteristics and the degree of contamination expected in a
given area. In the case of Merichem Company, pumps and dikes
were designed to handle as much as a two-inch rainfall of 15
minutes duration (Gloyna, Ford, and Eller,1969). Previous studies
had indicated that the first half inch of runoff was highly
contaminated, the second half inch was relatively uncontaminated,
and the remainder would be of relatively high quality. Based on
-72-
-------
T
5000
<4000
Q
§3000
CD
CD
2000
1000
WASTE ABATEMENT
TRAINING
PROGRAM
300 ACRE OXIDATION
POND ADDITION
I
1
I
I
1958
1959
I960
1963
1964
1965
1961 1962
YEAR
FIGURE 17
AVERAGE DAILY EFFLUENT BOD LOADING. SEADRIFT PLANT UNION CARBIDE, INC.
(Rosengarten, 1969)
1966
-73-
-------
these investigations, the first half inch was collected and stored
for eventual treatment, the second half inch was used as cooling
water makeup, and the excess storm water overflow was determined
to be of a quality suitable for release directly to a nearby water
course.
IN-PLANT WATER AND WASTEWATER TREATMENT SYSTEMS
Isolation of potentially highly contaminated wastes identified
during the course of the wastewater survey assists in locating
product recovery systems or treatment units as well as the implemen-
tation of separation operations which may be highly effective in
reducing a pollutant source. Examples include sour water strippers
or deionizers, direct return of process spills to the process,
or use of one waste stream to treat another such as using debutanizer
bottoms to extract oils, phenols, and H~S from quench water
processes, spent acids or caustics for neutralization, etc.
Another method of reducing the waste load is routing conta-
minated wastes to the cooling towers, transforming the tower into
a treatment unit to remove phenols, I^S, and other organics. The
Merichem Company applied this method by returning contaminated
storm water to the cooling towers. Organic wastes, heavy metals,
and other pollutants are removed by a combination of biodegradation,
precipitation, sorption, and volatilization. The amount of sludge
buildup in the recycled water is an important consideration since
it can interfere with cooling operations by fouling heat exchangers
and cooling tower equipment. Merichem's cooling towers, however,
operated for over a year while experiencing a minimum of difficulty.
-74-
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THE TREATABILITY STUDY
The necessary prerequisite in the formulation of design criteria
for industrial wastewater treatment facilities is a treatability
study programmed to provide key information relative to the removal
of pollutants. The preliminary characterization analyses may
be indicative of the types of unit processes applicable in
removing various pollutants, but a treatability study is necessary
to describe and relate process removal kinetics to the nature
and concentration of wastewater contaminants.
There are several approaches which can be employed to
evaluate the individual processes which comprise a total waste
treatment system. The most obvious technique for process evaluation
is to simulate alternate systems on a bench or pilot scale and
measure the necessary parameters at various conditions. It should
be recognized, however, that the accuracy of information developed
from process simulation depends on several factors, vis:
1. The characteristics of the wastewater used in the treat-
ability tests are representative of those anticipated in
the field.
2. The physical nature of the bench or pilot scale process
is similar to the prototype unit.
3. Independent and dependent operational variables are
considered.
4. Environmental parameters affecting process efficiency are
defined.
It is apparent from these constraints that the process
simulation technique can provide predictor relationships and
equations for the treatment process and wastewater in question,
but does not necessarily define a specific model with general
applications. However, a treatability study which is properly
programmed and judiciously implemented does afford the basis for
the logical development of unit process selection, design, and
predictive performance.
The unit processes considered herein are categorized and
tabulated for the purpose of this report according to Table 17 ,
A general flow and sequence diagram including those unit processes
is illustrated in Figure 18.
Each of the processes cited will be discussed, with bench
or pilot scale equipment illustrated as applicable. Although many
-75-
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TABLE 17
CATEGORIZATION OF UNIT PROCESSES
Process Identification
Unit Process
PRIMARY TREATMENT:
P-l
P-2
P-3
P-4
P-5
P-6
P-7
SECONDARY TREATMENT:
S-l
S-2
S-3
S-4
S-5
S-6
S-7
TERTIARY TREATMENT:
T-l
T-2
T-3
T-4
Oil Separation
Equalization
Neutralization
Primary Clarification
Flotation
Flocculation-Clarification
Nutrient Addition
Activated Sludge
Extended Aeration
Trickling Filter
Aerated Lagoons
Waste Stabilization Ponds
Chemical Oxidation
Nitrification-Denitrification
Chemical Coagulation -
Precipitation*
Gas Stripping"
Rapid Sand Filtration
Microstraining
Carbon Adsorption
-76-
-------
TABLE 17 (Cont)
CATEGORIZATION OF UNIT PROCESSES
Process Identification
Unit Process
TERTIARY TREATMENT (Cont.):
T-5
T-6
T-7
T-8
T-9
SLUDGE HANDLING AND DISPOSAL:
SH-1
SH-2
SH-3
SH-4
SH-5
SH-6
SH-7
SH-8
SH-9
SH-10
SH-11
SH-12
ULTIMATE DISPOSAL:
UD-1
UD-2
Electrodialysis*
Ion Exchange*
Evaporation
Reverse Osmosis
Disinfection by Chlorination
Aerobic Digestion
Anaerobic Digestion
Heat Treatment - Wet
Oxidation
Thickening
Lagooning
Sand Drying Beds
Vacuum Filtration
Centrifugation
Filter Press
Land Disposal
Incineration
Sludge Transportation-Sea
Disposal
Thermal Oxidation
Deep Well Disposal
May be categorized as primary treatment in certain instances,
-77-
-------
Ultimate Disposal
PRIMARY
Spent Regenerate 8
Brine Disposal
SECONDARY TERTIARY
. T-2
iiiMiiiimMimiiiimiimiimiiiimmiiiimiiimmtmi!:'/
U
5
"1
ku
G
n
Itnilllimilllllllllllllllllh
Final
Effluent
Mill
imllmllimMHHItl
I '. "I ' ,11,Ml
Separate
Disposal
or ;
Oil Recovery
T-6
- - Q«9 -' :~
r;^. I. ... . .&. *s-^ , i::
&r TTi
~-' -tli( v.pjicUPt!)!--
^---~
<- ^.-> -.r l~8
>, ff T \ a
F,»ed or VX-, i "''evt'r'j' i -;
iponded f,'i ij'-tii- .tiill^-'
Hnd , . v ' ^ "" / -"
Cor lion
To Sludge Disposal
\ ' r .-J Heat ! ^ =
s i freotment f S
' i SH-3 1 ' /^N
_^ . _'.L- (Thickeninal
SH-4
SupernatoTl. Return &
Secondary -ireat."';"it (La.Tj.jmnci.-.
SH-5^^', !
FIGURE 18
WASTEWATER TREATMENT FLOW DIAGRAM
-78-
[' ! I Aerobic or [
i. Afinerob'c '
SH-9
-------
of the experimental procedures and design calculations are outlined
in detail elsewhere (Eqkenfelder and Ford,1970), a general des-
cription of these processes within the context of process simula-
tion and treatability is presented herein.
PRE OR PRIMARY TREATMENT
There are many impurities in petrochemical or refinery waste-
waters which must be removed or altered u^ing pre or primary treat-
ment processes before subsequent secondary treatment; operations
can be considered.
Excessive concentrations of suspended solids discharged directly
to secondary biological processes normally decrease overall process
efficiency, either by reducing the active biological-solids fraction
or by adversely affecting the sludge recycle and wastewater-contact
systems. As a consequence, gravity sedimentation or flotation units
are used to reduce suspended materials. The removal of suspended
or colloidal materials often can be enhanced by applying chemical
coagulation in conjunction with sedimentation or flotation.
The removal of oj.1 or grease by gravity separation is required
in many instances as these contaminants have a deleterious effect
on most secondary and tertiary treatment processes. Since free
oils are easier to remove when the concencention is high, oily
waste streams generally should flow through gravity separators
prior to dilution with non-oily waste streams. Adding chemicals
is often required to enhance separation, particularly when emul-
sions are present.
Extreme acidity or alkalinity must be neutralized before
most secondary treatment processes can be properly applied. Al-
though a biological system provides some buffering capacity (by
virtue of such mechanisms as biodegradation of organic acids,
respiratory carbon dioxide neutralization of caustic alkalinity,
etc. ), the presence of free mineral acidity or excessive alkalinity
in wastewaters dictates a specific neutralization step.
Extreme variations in organic loadings as well as slug dis-
charges of vari°us organic and inorganic constituents can have an
adverse effect on the operation and efficiency of primary, secondary,
or tertiary treatment processes. Fluctuations in hydraulic loadings
have a similar effect. When such conditions are anticipated,
equalization and surge facilities are required.
Specific anions such as sulfides or chlorides affect various
unit processes in a variety of ways. For example, high chloride
-79-
-------
concentrations alter biochemical reactions and adversely affect the
gravity separation of biological sludges. Toxic or bio-static
effects of inorganic constituents such as ammonia or heavy metals
or organic compounds such as phenols are well documented and the
presence of such materials often necessitates pre or primary treat-
ment steps. Approximate threshold conditions which indicate
the need for including pre or primary treatment processes are
summarized in Table 18. The pre or primary treatment processes
as categorized in Table 17 are listed herein and are described
in terms of their treatability or preliminary investigation require-
ments .
Oil Separation (Gravity)
Description of Process
Gravity oil separators are flow-through systems which allow
separation of oily substances from the carrier wastewater through
a gravity differential. The primary tunction of the separator
is to separate free oil from the wastewater, but it will neither
allow separation of soluble substances nor break emulsions (Manual
on Disposal of Refinery Wastes,1969).
In general, oil separators are rectangular, multi-channel
structures designed in accordance with the specifications of the
American Petroleum Institute (API). Other types of separators
which have performed satisfactorily include circular separators,
parallel plate separators, and special purpose separators.
Design Considerations and Process Variables
1. flow
2. rise rate of oil globules in wastewaters
3. turbulence correction factors
40 type and concentration of oil
5o temperature of wastewater
6. viscosity and specific gravity of the wastewater
7. geometry of basin
Preliminary Investigation Requirements
The feasibility of removing or recovering oils using
gravity separators can be estimated using a separatory funnel in
accordance with the standard API Procedure 734-53 (Methods for
Sampling and Analyses of Refinery Wastes, API,1969).
-80-
-------
TABLE 18
PRE OR PRIMARY TREATMENT REQUIREMENTS
Constituent
Limiting or Inhibitory
Concentration
Treatment
Suspended Solids
Oil or Grease
Heavy Metals
Alkalinity
Acidity
Organic Load Variation
Sulfides
Chlorides
Phenols
Ammonia
Dissolved Salts
>125 mg/1
>50 mg/1
< 1-10 mg/1
0.5 Ibs alkalinity as
CaCO- Ib BOD removed
Free mineral acidity
> 4:1
>100 mg/1
>8,000 - 15,000 mg/1
> 70 - 160 mg/1
> 1,600 mg/1
>16,000 mg/1
Lagooning, sedimen-
tation, flotation
Skimming tank or
separator
Precipitation or ion
exchange
Neutralization for
excessive alkalinity
Neutralization
Equalization
Precipitation or
stripping
Dilution, deioniza-
tion
Stripping, provide
complete mixing
Dilution; pH adjust-
ment and stripping
Dilution, ion
exchange
-81-
-------
Equalization
Description of Process
Equalization is a method of retaining raw wastewaters in
a basin which dampens the fluctuation in its characteristics. The
basin should be sized according to the cyclic pattern of the in-
dustrial plant operation within practical limits.
If a basin is designed solely to provide for dampening
out fluctuations in flow rate, there is no incentive to provide
mixing. However, some form of mixing should be provided if waste-
water constituents are to be dampened and equalized. This mixing
can be provided using proper distribution and baffling techniques,
diffused aeration, or mechanical agitation.
Design Considerations and Process Variables
1. flow variations
2. variations in wastewater constituents
3. cyclic patterns of industrial process operations
4. distribution of wastewaters
5. detention time
6. tank geometry
7. degree and type of mixing
Preliminary Investigation Requirements
The effect of transient organic or hydraulic loads on a
given process operation can be simulated on a bench or pilot
scale by varying the feed rates or concentration levels of the
wastewater to the unit process in question for defined periods of
time. An approach to evaluating the effects of transient loads
on biological systems and thereby establishing the criteria for
equalization requirements has been recently published (Adams
and Eckenfelder,1969).
Neutralization
Description of Process
It is not uncommon for petrochemical or refinery waste-
waters to contain acidic or alkaline materials which require
-82-
-------
neutralization prior to subsequent treatment. Neutralization can
be accomplished by the use of mixing basins, flow-through beds,
or gas sparging.
Acid streams can be neutralized by mixing the waste
with lime slurries, dolomitic lime slurries, or by adding caustic
soda (NaOH) or soda ash (Na2CC>3). Limestone beds are occasionally
used, either as an upflow system or as a downflow system. Alka-
line streams can be neutralized with acid (sulfuric, t^SO,, or
hydrochloric, HC1) or with boiler flue gas (C02). Bottled
CCL is applied to alkaline wastes in a manner similar to that of
a diffused air system in an activated sludge plant. It neutralizes
alkaline wastes by the same mechanism of flue gas neutralization,
i..§_. > the forming of a weak carbonic acid when dissolved in water.
Design Considerations and Process Variables
1. alkalinity/acidity
2. quantity of sludge produced
3. flow
4. reaction velocity
5. depth and flow rate (limestone beds)
6. degree of mixing (mixing basins)
7. feed rate of neutralizing agent
8. geometry of mixing basin
Preliminary Investigation Requirements
The neutralization requirements for a mixing basin system
can be estimated in the laboratory by taking samples representative
of the alkalinity or acidity level in the wastewater and deter-
mining the equivalents per day of neutralizing acid or base re-
quired to obtain the desired pH. If limestone beds are to be
used, bench scale neutralization columns such as those shown in
Figure 19 can be used.
Primary Clarification
Description of Process
Sedimentation is a process employed in wastewater treat-
ment to remove solids from suspension. Most suspended materials
-83-
-------
LIMESTONE
COLUMN
/ _ II _ll . ,. V
(3-5 in diom.)
ACID WASTE
f X
1 " 1
titm
s&
mw
mn
#$?;$i
mm.
*#$>.*
/t&;;^:
p$
fern
tel
^f
:'^Vv:».
M-!VS
1
PRIIQHFn 1 IMF^TONF
^r\uonc.u UIIVIL.O i VJIML.
\\ .NEUTRAL
^ , _ r s t A i A f*, ^ r*
|s -\(X WASTE
|J- il
1 -J
FIGURE 19
BENCH SCALE LIMESTONE COLUMN
-84-
-------
in raw petrochemical or refinery wastewaters undergo flocculent
settling under quiescent conditions. With this type of settling,
particles agglomerate during the settling period with a consequent
change in specific gravity and settling velocity.
In the gravity separation of flocculent suspensions, both
clarification of the liquid overflow and thickening of the sludge
underflow are involved. Sedimentation units are either circular
or rectangular and usually have a side water depth of approximately
10 feet.
Design Considerations and Process Variables
1. flow
2. overflow rate
3. suspended solids concentration in raw wastewater
4. desired underflow concentration
5. settling velocity of suspended solids
6. detention time
7. variation in suspended solids concentration
8. structural & weir configurations of clarification basin
9, sludge raking mechanism and raking speed
10. mechanism of wastewater feed and effluent discharge
Preliminary Investigation Requirements
The basic design criteria for sizing primary clarification
units can be developed using bench scale batch settling tests or
pilot scale continuous flow clarifiers. The batch settling cylinder
as used in the laboratory is shown in Figure 20. The concentrations
of suspended materials are observed at various levels for various
settling times, and this data .can subsequently be formulated into
the design,
Flotation
Description of Process
Flotation is a process used to separate the solid phase
from the liquid phase, having the same objectives of gravity
sedimentation. However, separation of the 2 phases is enhanced
by the pressurization of the incoming or recycled wastewater,
-85-
-------
SLUDGE
SAMPLING
2' PORTS
6" O.D.
5 1/2 I.D.
8'
r-PLEXIGLASS
--> CYLINDER
12"
FIGURE 20
LABORATORY SETTLING COLUMN
-86-
-------
the release of which provides minute bubbles which attach themselves
to or become enmeshed in the suspended particles. The air-solid
particles rise to the surface of the flotation unit from which
they are removed by a sludge collection mechanism, while the
underflow represents the clarifier effluent.
Flotation units are often applicable in removing or
reducing the concentration of oily materials present in petro-
chemical or refinery wastewaters. It is not uncommon to employ
gravity separation devices followed in series by flotation
units. The efficiency of a flotation unit in removing oil
depends on the nature of the oil, its initial concentration,
and the level of associated particulate matter. Chemical co-
agulants are occasionally used to enhance the separation
process.
Design Considerations and Process Variables
1. flow
\
2. recycle ratio
3, air/solids ratio
4. detention time
5. rise rate
6. overflow rate
7. solids loading
Preliminary Investigation Requirements
The applicability of the flotation separation of solids
from liquids can be determined on a bench or pilot scale. Such
an evaluation can be made using the pressurized chamber apparatus
shown in Figure 21. The wastewater is pressurized and proportion-
ately mixed with additional water in an open container. The rise
rate and concentration of the floated material is then ncted and
used as a basis for the selection and design of flotation systems.
Coagulation - Precipitation (Reactor-Clarifiers)
Description of Process
Reactorclarifiers are used to combine chemical coagulation-
precipitation with gravity sedimentation. These units are particu-
larly applicable when the addition of chemicals significantly
enhances the removal of colloidal and suspended materials. Most
reactor-clarifiers employ concentric baffles with the center
compartment containing chemical feed and mixing appurtenances.
-87-
-------
PRESSURE
GAUGE
COMPRESSED VALVE
SOURCE ' CHECK n T
NUT L
AIR ^^;
SPARJER**^^
PRESSURE
CHAMBER SUPPORT
Accpyoi v j
MOOL.IVIDLT ,^C
Us~***\
if,
0^3 K
;
L.-^
:::
-
||:
b 4
i i
/
i
i
AIR BLEED
VALVE
-BOO
GRADUATE
CYLINDER
(for mixing waste-
water and sludge
with pressurized
liquid)
PRESSURE CHAMBER
(1.5-2 liter capacity)
FIGURE 21
BENCH SCALE FLOTATION UNIT
-88-
-------
A scraping mechanism is used in the bottom portion of the quiescent
zone to allow for collecting and concentrating the resulting sludge.
Design Considerations and Process Variables
1. flow
2. overflow rate
3. suspended solids concentration in raw wastewater
4. desired underflow concentration
5. effect of various chemical coagulants on settling
velocities and underflow concentration
6. dosage of chemical coagulants
7. pH effect on chemical coagulation & precipitation
8. size of reactor compartment and level of mixing
9. sludge raking mechanism ard raking speed
10. mechanism of wastewater & chemical feed & effluent
discharge
Preliminary Investigation Requirements
The efficacy of using chemical coagulation-precipitation
can be assayed in the laboratory using the standard jar test pro-
cedure, varying the pH, coagulant, and. coagulant dosage, to
determine the conditions for maximum removals of suspended
materials or organic constituents. The effectiveness of adding
coagulants to a wastewater is normally measured in terms of
color removal, organic reduction (such as TOG, BOD, etc. )f and
suspended solids removal.
Nutrient Addition
Description of Process
Efficient and successful biological oxidation of organic
wastewaters requires a minimal quantity of nitrogen and phosphorus
necessary for the synthesis of new cellular tissue. Since many
petrochemical and refinery wastewaters are deficient in both
constituents, facilities must be provided to supply the wastewater
with these critical nutrients (Eckenfelder and O'Connor, 1963).
Nitrogen in the form of anhydrous ammonia, nitrite, nitrate,
and some forms of organic nitrogen are available to microorganisms,
although it is normally assumed that nitrogen is taken into the
cell in the form of ammonia. This means that a reduction of
nitrite and nitrate-nitrogen is required before nitrogen is
-89-
-------
available as a nutrient source. Phosphorus is usually added
in the form of phosphoric acid or soluble phosphorus salts
since they are the most readily assimilable. It is generally
assumed that a BOD/N/P ratio of 100/5/1 is required for proper
microbial respiration and reproduction, although an alternate
way of calculating the requirement is based on the daily
synthesis sludge production; vis,
Nitrogen requirement = 0.123 (sludge production/day)
Phosphorus requirement = 0,026 (sludge production/day)
Nitrogen or phosphorus storage tanks are located in the proximity
of the raw wastewater influent to secondary biological treatment
facilities.
Design Considerations and Process Variables
1. organic load in terms of BOD
2. nutrient feed rates
3. mixing of applied nutrients with incoming wastewater
4. form of nitrogen and phosphorus and level of purity
5. levels of nitrogen and phosphorus in wastewater
Preliminary Investigation Requirements
The effect of nutrients on biological systems can be evalu-
ated on a bench or pilot scale by measuring the organic removal
obtained in biological facilities with varying concentrations of
nutrients added.
JECONDARY TREATMENT
Secondary treatment is applied to reduce dissolved organic
constituents through chemical or biochemical oxidation to a level
acceptable for discharge into a receiving body of water or to the
point where tertiary treatment can be effectively employed. Bio-
logical systems are the most common processes used for secondary
treatment, although chemical oxidation, which has a more restric-
tive application, can be similarly classified. Commonly used
biological treatment systems include activated sludge, extended
aeration, aerated lagoons, trickling filters, and waste stabiliza-
tion ponds. The biological transformation and removal of nitrogen
through nitrification-denitrification processes is classified
for the purpose here as a secondary treatment, although such a
system sometimes is categorized as a tertiary process.
-90-
-------
Screening analyses often are necessary to distinguish bio-
logically treatable streams from those which are biologically
resistant or toxicological. This is partially true in a complex
petrochemical facility where a treatability evaluation of major
waste streams is required in order to plan the total waste
treatment system. Biological screening tests can be conducted
using either manometric techniques or bench scale batch reactors
(Eckenfelder and Ford, 1970). These screening procedures will
be discussed individually.
1. Batch Reactor Screening Analyses
A series of small batch-type biological reactors
as shown in Figure 22 can be used to accomplish the
same objectives as the Warburg approach. An acclimated
seed is added to each of a series of batch units, then
either various concentrations of a single waste stream
or wastewater samples from each stream are added at a
volume proportioned by flow to each reactor. Results
such as those shown in Figure 23 indicate apparent
toxicity or inhibition, using COD or BOD removal as
a comparative index.
2. Manometric Analyses (Warburg Respirometer)
The Warburg Respirometer can be used to obtain a
cursory estimate of the effect of various waste streams
on biological cultures by measuring the biological
response in terms of oxygen uptake for different
classifications and concentrations of wastewater.
This can be accomplished using an approach similar
to that described in Manometric Techniques. An
acclimated biological seed plus the wastewater sample
are added to the manometric flask. As the microorganisms
utilize the organic constituents of the wastewater, the
corresponding pressure differential in the closed system
resulting from oxygen utilization is recorded. Results
as shown in Figure 24 indicate the percent by volume of
the particular waste stream which is toxic or inhibitory
to a biological system (allowance should be made if lag
periods of oxygen utilization caused by the incomplete
acclimitization of the biological seed occurs).
Chemical oxidation is not economically competitive with bio-
logical oxidation for most applications, but it offers several
conceptual advantages. It is not overly sensitive to fluctuating
environmental conditions, is generally more efficient in the attack
on stable or refractory compounds, and can effectively be controlled
and regulated.
The secondary treatment processes as tabulated in Table 17
are described in terms of their preliminary investigation require-
ments .
-91-
-------
CAPACITY
IN LITERS
( 1.5 Liter Cap.)
SAMPLE s
WITHDRAWAL >K
POINTS
AIR DIFFUSERS
WATER TRAP
COMPRESSED
AIR SYSTEM
FIGURE 22
BATCH REACTOR
-92-
-------
100
UJ
IT
O
O
O
O
o
CD
cr
UJ
o.
II .11
100 H
SEED -I- 10% STREAM "A
it. N
SEED + 15% STREAM *A
SEED + 20% STREAM A
SEED + 30 % STREAM "A"
12 24
AERATION TIME, HOURS
""
STREAM "B
12
AERATION TIME, HOURS
24
FIGURE 23
SCREENING PROCEDURES USING BATCH BIOLOGICAL REACTORS
-93-
-------
100-
90
80
70
60
g 50
40
30
20
10
0
SEED + 10% WASTE
X
SEED + 5% WASTE
SEED + 2% WASTE
........
SEED ONLY
SEED -i- >IO% WASTE
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
REACTION TIME (hrs)
FIGURE 24
DILUTION EFFECT ON RESPIRATION RATES
-94-
-------
Activated Sludge
Description of Process
The activated sludge process provides an environment in
which flocculated biological growths and wastewater are con-
tinuously mixed in the presence of dissolved oxygen. The
microorganisms remove organic materials from the waste through
physical sorption and aerobic biological oxidation. The
biological floe suspensions are then separated by settling,
recirculating a portion of the thickened sludge to the aeration
basla for contact with additional waste. Excessive sludge
accumulation must be wasted and subsequently treated. Oxygen
and mixing in the aeration basin are provided by diffused or
mechanical aeration.
Design Considerations and Process Variables
1. organic loading
2. environmental factors (pH5 temperature, etc.)
3. nature of wastewater and fluctuation in
characteristics
4. level of mixing in aeration basin
5, geometry of mixing basin
6. nature of sludge
7. nutritional requirements
Preliminary Investigation Requirements
The activated sludge process can be evaluated in the
laboratory using the batch reactors shown in Figure 22 or a
continuous flow reactor such as the one shown in Figure 25.
Although batch-type studies are acceptable for screening
analyses and approximating organic removal rates and effluent
levels, bench or pilot scale continuous studies are recommended
for the development of design criteria. This is predicated on
the following factors:
1. Food/microorganism ratios which dictate process
kinetics reach equilibrium values in continuous
reactor studies, and this information can be more
accurately translated to continuous-flow prototype
units. Process kinetics are highly dependent on
the time variable in batch reactor studies.
-95-
-------
FEED BOTTLE
SIGMA
PUMP
INFLUENT
FEED LINE
AIR
DIFFUSER
STONE
SLIDING
BAFFLE
ADJUSTABLE
OVERFLOW
WEIR
EFFLUENT
BOTTLE
FIGURE 25
CONTINUOUS FLOW LABORATORY REACTOR
-96-
-------
2. Oxygen requirements and sludge growth rates observed
in continuous reactors have been shown to approxi-
mate those values observed in full-scale units when
operating conditions are the same. Predictor data
derived from batch data has been more inaccurate,
and,
3. The impact of toxic or inhibitory substances, and
variation in flow and constituents, on the bio-
logical system can be more accurately evaluated
for continuous systems when continuous bench or
pilot scale reactors are used.
Extended Aeration
Process Description
Extended aeration is a modification of the activated
sludge process where the organic loading is sufficiently low to
allow oxidation of biological solids (endogenous respiration),
thus minimizing the excess sludge production attributable to
biological synthesis. The sludge is theoretically nonbiodegradable
residue but still contains an active biological fraction.
Extended aeration facilities generally are most applic-
able when the design wastewater flow is less than 2 to 3 MGD
because of the tank volume requirements.
Design Considerations and Process Variables
1. organic loading
2. environmental factors (pH, temperature, etc. )
3. nature of wastewater and fluctuations in
characteristics
4. level of mixing in aeration basin
5. geometry of mixing basin
6. nature of sludge
7. nutritional requirements
Preliminary Investigation Requirements
The extended aeration process can be evaluated in a manner
similar to that of the activated sludge process. The detention
time (or organic loading) required to minimize sludge production
can be estimated by evaluating the sludge production per unit
-97-
-------
time for each of the continuous bench scale reactors subjected to
varying organic loadings. The loading at which sludge production
is minimized can be considered the point where the system by
definition is extended aeration.
Trickling Filters
Description of Process
Trickling filters use a biological slime coated on a
fixed media bed to remove dissolved and colloidal organic
materials as the wastewater flows through. As the wastewater
comes into contact with the slime, the organic material and
oxygen diffuse into the growths where biochemical oxidative
reactions occur.
The characteristics of the media should be such that
it provides not only a maximum contact surface area of active
biological mass, but also allows maximum wastewater-slime contact
time without filter plugging. Good ventilation throughout the
filter bed is also required.
Design Considerations and Process Variables
1. filter depth
2. filter media
3. hydraulic and organic loading
4. wastewater characteristics
5. environmental factors (pH, temperature, etc.)
6. recycle pattern
7. nutrient requirements
Preliminary Investigation Requirements
Trickling filters can be evaluated in the laboratory
using a filter model as shown in Figure 26. By varying the
hydraulic load, filter depth, and recycle ratio, the parameters
necessary for developing the predictor equations can be measured,
and the constants which define the substrate removal and filter
media can be estimated (Eckenfelder and Ford, 1970).
-98-
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FEED DISTRIBUTION
PLEXIGLASS -\
7 1/2"$ x 18"
PERFORATED PLATE -,
FOR FLOW DISTRIBUTION
(REMOVABLE FOR
CLEANING)
7 1/2" 0 PLEXIGLASS
COLUMN 7' HIGH
SIGMAMOTOR PUMP
^LIQUID
^SAMPLING
PORTS
0/4" TUBING)
MEDIA
SAMPLING
2' PORTS
2 1/2"
SETTLING TANK
SUBSTRATE
RESERVOIR
SLUDGE RECIRCULATION
LINE
MEDIA
SCREEN (f xl" MESH)
SLUDGE DRAIN
FIGURE 26
BENCH SCALE TRICKLING FILTER
-99-
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Aerated Lagoons
Description of Process
Aerated lagoons are biological flow-through basins
generally applicable when a high quality effluent in terms of
suspended solids or organic concentration is not required.
Aerated lagoons are more sensitive to temperature changes and
biological upsets than activated sludge systems, but serve as
good intermediate treatment processes.
Oxygen in aerated lagoons is supplied by diffused air
systems or mechanical aeration devices, but the power level of
the system is normally insufficient to keep all the biological
solids in suspension. Solids deposition with subsequent an-
aerobic digestion is therefore common in aerated lagoon systems.
These systems may be considered as an interim treatment
step in some cases because their organic removal capacity can be
enhanced by converting to an activated sludge or extended
aeration system by adding clarifiers, sludge return pumps, and
additional aeration equipment.
Design Considerations and Process Variables
1. organic loading
2. environmental factors (pH, temperature, etc. )
3. nature of wastewater and fluctuations in
characteristics
4. level of mixing in aeration basin
5. nutritional requirements
6. basin depth and geometry
7, wind, heat transfer coefficient, humidity effects
Preliminary Investigation Requirements
Aerated lagoons can be evaluated in the laboratory using
a continuous reactor similar to that for activated sludge, but
providing a strict flow-through system with no facilities for
quiescent sludge settling. Aerated lagoons can be simulated on
a pilot plant scale by using lined earthen tanks with small
mechanical aeration equipment to supply oxygen and partial mixing.
-100-
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Waste Stabilization Ponds
Description of Process
Waste stabilization ponds are biological processes which
utilize bacteria and algae to fulfill the process treatment
requirements. The available organic materials in the incoming
waste are oxidized biochemically while algae, utilizing the
simpler bacterial degradation products and sunlight, produce
oxygen which is subsequently used by facultative and aerobic
microorganisms.
If a high organic loading to a pond exerts an oxygen
demand above that provided by photosynthesis and surface reaeration,
anaerobic or facultative bacteria will predominate. When this
occurs, alcohols, various forms of organic acids, and other miscel-
laneous degradation products of anaerobic degradation will be
produced.
Many complex organic compounds not degraded in the con-
ventional activated sludge process or aerated lagoons can be
degraded in a waste stabilization pond because of the prolonged
detention times. Therefore, it is feasible in many cases to use
an aerated lagoon or activated sludge-waste stabilization pond
system, especially where complex petrochemical or petroleum
wastewaters are involved.
Design Considerations and Process Variables
1. nature of wastewater organic & inorganic constituents
2. flow, detention time
3. surface loading
4. geometry and depth of pond
5. environmental conditions (pH, temperature, etc.)
6. geographical location
7. color, toxic materials, solids, etc., of wastewater
Preliminary Investigation Requirements
Waste stabilization ponds can be simulated in the labora-
tory using models and an artificial lighting system as shown in
Figure 27. Both flourescent and incandescent lighting should be
provided with an intensity of approximately 600-800 foot candles.
A compressed air source should be affixed close to the liquid
surface to simulate wind action. The organic removal efficiency
at defined surface loadings and detention times can be estimated
-101-
-------
Light
System
f u u u
1 U U U
Influent i f
>
*
**
\
~r^-^=r
_
I
\
* -
1 -=-^- >^%»f
^T <* VI
_f ^
X
^
---/--
/
_/
/
/
_^
V
\
\
\
V
rjLJ
I
J
_f
1
1
*
u
Effluent
(b) Botch Model
Vol. = 3 liters
Area - 184 cm2
(a) Continuous Model
Vol. = 45 liters
Area = 1500 cm2
FIGURE 27
WASTE STABILIZATION POND MODELS
-102-
-------
using such a model as well as algal toxicity factors, environ-
mental effects, etc. Larger scale test ponds can be constructed
outside for conducting pilot studies if required.
Chemical Oxidation (Ozone Treatment)
Description of Process
Wastewaters discharged from many petrochemical or
refinery processes are complex and highly resistant to bio-
logical degradation. This necessitates some alternate form
of secondary treatment. Chemical oxidation using ozone has
proved effective for specific wastewaters.
The chemical oxygen demand (COD) of a wastewater con-
taining unsaturated organic compounds can be reduced by ozone
oxidation, and the effectiveness of this reduction in terms of
ozone utilization can be defined as the number of oxygen atoms
reacting with the waste constituents with the consequent re-
duction in COD per ozone molecule adsorbed (Kwie, 1969).
Depending on the extent of oxidizable or unsaturated compounds
in the waste, one or all three of the oxygen atoms per ozone
molecule can remain chemically attached to the waste constituent
during ozonation.
Design Considerations and Process Variables
1. nature of the organic materials (amount of
unsaturates)
2. the pH of the wastewater
3. voltage and rate of oxygen flow-through
4. the ozone generator
5. type of ozone distribution system
Preliminary Investigation Requirements
The amenability of wastewater to ozone oxidation can
be evaluated using bench scale apparatus shown in Figure 28
(Eckenfelder and Ford 1970). The ozone-oxygen gas is bubbled
through the wastewater sample contained in the reaction flask.
The ozone utilization and the corresponding COD reduction then
can be evaluated in terms of an oxygenation factor:
,-lbs COD removed-1
Ibs ozone used
-103-
-------
OZONATOR
REACTION
FLASK
DRYER
POTASSIUM
IODIDE
TRAPS
WET TEST
METER
FIGURE 28
LABORATORY SCALE OZONE TREATMENT
-104-
-------
Nitrification - Denitrification
Description of Process
The 2-stage conversion of ammonia to nitrate by micro-
organisms is well documented (Delwiche, 1956; Henrici and Ordal).
This nitrification process is influenced by the substrate or
carbon loading, the temperature, and the pH. As these and other
variables are critical with respect to the oxidation reactions,
the design of nitrification tanks must incorporate these factors.
The removal of nitrogen from nitrified effluents can be
effected using biological denitrification methods (Sawyer and
Bradney, 1945; McKinney and Conway, 1957; Symons and McKinney,
1958). This is an anaerobic process and is likewise sensitive
to many environmental stresses. It is the opinion of many
investigators that a series nitrification-denitrification
system is a practical method for nitrogen removal (Wuhrmann,
1962; Oechsner). However, when comparing this method of
nitrogen removal to alternate systems such as ammonia
stripping or ion exchange, it is necessary to consider all
the variables which affect the efficiency of the process, the
operational problems involved, the quality of the effluent
required with respect to total nitrogen, and the process
economics.
Design Considerations and Process Variables
1. organic loading
2. environmental factors (pH, temperature, etc.)
3. mixed liquor dissolved oxygen
4. concentration and form of influent nitrogen
5. sludge age
6. aerobic detention time (nitrification) and an-
aerobic detention time (denitrification)
Preliminary Investigation Requirements
Nitrification and denitrification have been evaluated
using both bench scale and pilot scale studies (Balakrishnan and
Eckenfelder, 1968; Oechsner; Earth, et al, 1968).
Bench scale studies involve the use of continuous reactors
and trickling filters to obtain nitrification, varying influent
carbon, nitrogen, and altering environmental conditions in order
to determine the effect of process variables on nitrification
rates and capacities. Pilot scale use of filters and aeration
tanks have been similarly applied.
-105-
-------
The aspects of biological denitrification can be assayed
using continuous bench or pilot scale reactors with mechanical
mixing devices. The mixing levels should be sufficient to main-
tain a relatively homogeneous mixture of biological solids and
substrate but not capable of introducing oxygen to the liquid.
Again, process variables such as influent nitrate and carbon
concentration, mixed liquor solids, etc., are controlled in order
to evaluate their effects.
TERTIARY TREATMENT
The treatment of wastewaters by conventional primary and
secondary processes does not yield an effluent of sufficient
quality to meet the necessary criteria in many instances.
Tertiary or advanced wastewater treatment processes consequently
are required to remove these residual or refractory
contaminants.
Tertiary treatment processes are utilized to remove residual
suspended solids, including microorganisms, dissolved solids,
complex organics, and other pollutants such as nitrogen and
phosphorus compounds, and ABS. The tertiary treatment processes
as categorized in Table 17 are listed herein and are described
in terms of their treatability or preliminary investigation
requirements.
/v
Chemical Coagulation - Precipitation
Description of Process
Chemical coagulation-precipitation can be employed either
as a primary treatment or tertiary treatment step, depending on
the contaminants present and the desired level of removal. Lime
precipitation as a tertiary process for the removal of phosphorus
and organic carbon is considered in this section.
The lime precipitation system may be designed either as
a 2-stage lime process with lime addition to pH 11.5 in the first
stage followed by recarbonation to pH 9.5 to 10 with flocculent
additives in the second stage, or as a single-stage lime process
at pH 11.5 with sodium carbonate added to reduce excess calcium
ions (O'Farrell, Bishop, and Bennett, 1968). The application of
this system in polishing effluents from a secondary plant treating
petrochemical or refinery wastewaters would have to be verified
either by bench scale or pilot scale studies as the multiplicity
of contaminants present in such wastewaters could interfere with
the coagulation-precipitation reactions.
* This process is interchangeable with Pre or Primary Treatment
by Coagulation-Precipitation.
-106-
-------
Design Considerations and Process Variables
1. flow
2. concentration and nature of the contaminants
3. concentration of coagulant
4. detention time of mixing and clarification zones
5. dissolved oxygen and carbon dioxide concentrations
6. chemical purity of coagulant
7. temperature and pH of the liquid mixture
Preliminary Investigation Requirements
Bench scale tests using a batch "jar test" procedure can
be used, determining the optimum dosage and pH by varying parameters
and monitoring the contaminant removal for each condition (Ecken-
felder and Ford,1970). A continuous pilot plant simulation, al-
though more costly, would yield more dependable data. The range
of operating temperatures, coagulant dosages, and pH values, with
respect to contaminant removal, however, can be determined in
bench scale jar tests, using this information to establish pilot
plant operating conditions.
Gas Stripping
Description of Process
Stripping essentially is a form of distillation wherein
a small amount of a relatively volatile material is removed from
a large volume of less volatile material (Manual on Disposal of
Refinery Waste, Vol on Liquid Waste,1969). In refinery waste
disposal, the process is generally used for removing small amounts
of volatile impurities, .e..g.. , hydrogen sulfide, ammonia and cyanide
from large volumes of wastewaters. The method is not suitable
for removing materials of low volatility, such as phenolics,
because heating and equipment requirements make it uneconomical.
The most frequent use of stripping in refinery waste disposal
is for removal of hydrogan sulfide and ammonia from foul waters.
Gas stripping may be considered tertiary treatment or
pretreatment. For example, in the refinery industry, it is considered
part of pretreatment whereas in domestic wastewater treatment it
may be considered tertiary treatment. Stripping is a modification
of the aeration process, The process may be utilized to remove
-107-
-------
both ammonia and hydrogen sulfide under proper conditions of tempera-
ture and pH. Air requirements for ammonia removal may be decreased
by the inclusion of a pre-concentration step utilizing zeolyte
absorbents. Lime is normally used as a hydroxide source in the
ammonia removal process.
When the removal of hydrogen sulfide is desirable, a strip-
per can be applied. An acidic condition is necessary for the
efficient stripping of sulfides. Ammonia stripping necessitates
alkaline conditions as none of the ammonia is in the gaseous
state below pH seven.
Gas stripping is generally conducted in a packed tray
tower equipped with air blower. The towers usually are designed
so that the gas and liquid leaving a desorption plant are in contact
with gas containing little or no vapor absorbed from the liquid
(Bayley,1967). The wastewater is pumped to the top of the packed
tower where it is distributed uniformly over the packing through
which a steady stream of air or gas is drawn.
Design Considerations and Process Variables
1. waste flow
2. contaminant concentration
3. hydrogen ion concentration of wastewater
4. wastewater temperature
5. aeration transfer equipment
6. contact time
7. waste loading
8. air flow rate
9. nature and size of packing material
10. diameter of column
11. height of column
12. operating pressure and temperature in column
Preliminary Investigation Requirements
The first step in the design of a stripping column is
to fix its internal diameter. A permissible average gas rate of
-108-
-------
400 cubic feet per gallon may be assumed. For packed columns
this permissible rate is determined by flooding conditions for a
given plate efficiency. The internal diameter of the column
can be calculated directly from the permissible gas rate and the
volume of waste liquid to be passed through the column. Diameters
usually vary between three to six feet with the height being
determined by the equilibrium conditions in the column and by the
number of contacts necessary for the amount of stripping desired.
The realtionship between mass transfer coefficients determined
in the laboratory or from pilot plant data and corresponding
coefficients for full-sized towers have been studied exhaustively
(Bayley,1967). Provided conditions of flow in both systems are
turbulent, the performance of the full-scale unit may be estimated
quite rapidly from pilot plant information. A bench scale strip-
ping tower is shown in Figure 29.
Microscreening
Description of Process
Microscreening, or microstraining, is a form of simple
filtration. The objective is the clarification of liquids by the
removal of suspended solids, especially those of microscopic size.
The process involves the use of a horizontal, rotating drum-type
straining element whose periphery is enveloped with perforated
or mesh-type screening material. In use, a thin mat forms over
the fabric screen and as the wastewater enters the drum and passes
through the mesh fabric in radial directions, solids are strained
from the wastewater. The solids are retained on the inside
surface of the fabric and continually backwashed to waste. The
drum may be installed in a concrete or steel box. The weight or
volume of particles intercepted varies with the cube of the
screen apertures and therefore significant differences in efficiency
are obtained by using varying mesh sizes. This process has been
investigated as a potential pretreatment method preceding carbon
adsorption, distillation, solvent extraction, reverse osmosis,
freezing, and electrodialysis.
Design Considerations and Process Variables
1. flow
2. suspended solids
3. nature and sizes of suspended solids
4. variation of suspended solid concentrations
-109-
-------
STRIPPED GAS EXIT
WASTE INFLUENT-
HEATED WASTEWATER
HOLDING TANK
SAMPLING
PORT
6-T PLEXIGLASS
TUBES
I RASCHIG RINGS AND
BERL SADDLES
ROTAMETER
AIR
COMPRESSOR
FIGURE 29
BENCH SCALE GAS STRIPPING TOWER
-110-
-------
5. filtration area and rotation speed
6. presence of oil, grease, or other floatables
7. filter fabric mesh size
Preliminary Investigation Requirements
A microstraining plant cannot be designed in the same
manner as a rapid sand filtration plant (Boucher and Evans).
Rates of flow through the filtering media are much higher than
through sand beds; frictional resistance allowable is much less;
and the fabric is matted very rapidly by the solids intercepted.
The rate of filter blockage is measured in terms of filterability,
and this is designated as the filterability index (I). Given
this index from samples of the water in its poorest condition
of suspended solids applied and the grade of fabric employed,
the general problem of design is to determine the dimensions of
the strainers and rotation speeds required to pass the required
rate of flow.
The calculation of the filterability index may be performed
in many ways. The most accurate method is with the apparatus
devised by Boucher (1947), a laboratory set-up that measures the
head loss across a section of the filter being tested using the
waste in question. Another device has been developed for field
use but has been found to be less reliable (Bodien and Stenburg,
1966).
Suspended solids removals appear to be relatively un-
affected by feed concentration and removal efficiencies on the
order of 85 to 90 percent may be expected. The microscreening
process may best be evaluated on a pilot scale.
Carbon Adsorption
Description of Process
Adsorption of molecules from the liquid phase to the solid
phase occurs as the result of either electrical attraction of the
solute to the adsorption surface, Van der Waals forces, chemical
reactions, or possibly a combination of these phenomena. The type
of adsorption associated with the removal of organics is generally
caused by Van der Waals forces or "physical" adsorption and usually
occurs in three phases: the transport of the contaminant (adsorbate)
to the exterior surface of the adsorbing media (adsorbent); the
diffusion of the adsorbate into the pores of the adsorbent; and
the adsorption of the adsorbate on the surface of the adsorbent.
Activated carbon, carbonaceous material with certain adsorptive
-111-
-------
and catalytic properties, has an affinity for many contaminants
present in petrochemical or refinery wastewaters, and contact
between the carbon surfaces and the waste is achieved through fixed-
bed or expanded-bed carbon columns. Once breakthrough in the
volumn occurs (the column is in equilibrium with the wastewater),
the spent carbon is either wasted or regenerated for subsequent use.
Design Considerations and Process Variables
1. flow rate
2. contact time
3. depth of carbon bed
4. adsorptive capacity of adsorbent
5. influent solute concentration
6. allowable effluent solute concentration
7. particle size
8. environmental factors (temperature, pH, e±.c. )
Preliminary Investigation Requirements
Adsorption rates and general relationships can be formulated
using batch contact reactors or continuous columns. Carbon is
usually added to batch systems in powdered form and removed by
flocculation and sedimentation. This can be simulated in the
laboratory using test flasks and a shake assembly. The weight
of carbon added and the corresponding removal of organic material
for varying conditions is then translated into one of the isotherm
equations.
Serial continuous carbon columns usually offer the most
practical system for the polishing of effluents as the separation
of carbon from the wastewater after contact is not required. The
concentration of the adsorbed solute is in equilibrium with the
influent concentration rather than the effluent solute concentration
enhancing removal, and greater flexibility of operation is possible.
Electrodialysis
Description of Process
This process is based on the migration of positively
charged ions and negatively charged ions to respective oppositely
charged electrodes and on the ability of semi-permeable membranes
-112-
-------
to selectively permit the passing of ions of one type of charge while
repelling ions of the opposite charge. Electrodialysis is
specifically for ions and the membranes are essentially impermeable
to water.
The electrodialysis process is a form of tertiary treat-
ment and must be preceded by additional tertiary treatment including
filtration. Non-ionized molecules and suspended solids are not
removed during the process, and, if present, will cause membrane
fouling (Brunner, 1967). Sulfuric acid is used in the process to
abate membrane fouling, and the apparatus is arranged so that
concentrated and diluted streams flow continuously. Only partial
demineralization by this method is practical, however, because
electrical power requirements become excessive if the ion concen-
tration is reduced too far ("Summary Report - Advanced Waste
Treatment Research" 1962 to 1964). The power consumption is also
a function of the amount of ions that must be removed. Single-
pass electrodialysis will reduce the total dissolved solids
concentration in water by about 40 to 50 percent.
Design Considerations and Process Variables
1. membrane
a. size
b. area utilization
c. current density
d. thickness
e. resistance
f. bursting strength
g. liquid velocity
h. space between membranes
i. headloss through stack
2. stack design
a. flow
b. ionic characteristics of wastewater
c. influent and effluent ionic concentration
d. pH and stability of feed water
-113-
-------
Preliminary Investigation Requirements
The removal of inorganics may be defined by Farraday's
Law. The determination of electrical resistance and energy
consumption requires the knowledge of certain constants related
to the particular equipment used, the water, and temperature.
These design parameters may be determined through use of pilot
plant studies ("Electrodialysis in Advanced Waste Treatment".
1967). Such an electrodialysis pilot unit is shown in Figure 30.
Ion Exchange
Description of Process
Ion exchange is an exchange adsorption process in which
ions associated with the solid adsorbent are exchanged for ions
in solution and is used to remove undesirable anions and cations
from wastewater. Most ion exchange resins presently used are
synthetic resin materials consisting of a network of hydrocarbon
radicals to which are attached soluble ionic functional groups.
The total number of functional groups per unit weight of resin
determines the exchange capacity and the group type determines the
exchange equilibrium and the ion selectivity. Ion exchange resins
may be strong or weak acidic cation exchangers or strong
or weak basic anion exchangers. Generally, hydroxyl ions are
exchanged for the anions removed from solution while hydrogen
or sodium ions are replaced by the cations which are taken up by
the exchange media.
Design Considerations and Process Variables
1. applied feed rate per unit volume of resin
2. exchanger depth
3. backwash expansion
A. flow rate per unit area of resin
5. regenerate flow rate
6. rinse water flow rate
7. regenerate concentration
8. nature of resin
-114-
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INFLUENT.
ACTIVATED CARBON
COLUMN
ELECTRODIALYSIS STACK
VALVE
CONCENTRATE
RECYCLE PUMP
EFFLUENT
CATHOLYTE
CONCENTRATE
CONCENTRATE
* RESERVOIR
OVERFLOW
WATER
FEED
FIGURE 30
LABORATORY ELECTRODIALYSIS UNIT
-115-
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Preliminary Investigation Requirements
An ion exchange column as shown in Figure 31 can be used
to develop data necessary for design of prototype ion exchange units,
Based on the observed number of ion equivalents removed per unit
time, the resin volume requirement can be estimated. Additionally,
the rinre water and regenerate requirements can be predicted
(Eckenfclder and Ford,1970),
Evaporation
Uescription of Process
Evaporation is a process by which liquid is changed
to vapor. Although molecules of water are continuously leaving
the water surface, others are returning, and the rate of evaporation
is determined by the net accumulation of those leaving the water
surface. If the temperature of the surface is to be maintained,
large quantities of heat must be supplied by radiation and conduction
from the overlying air or at the expense of any heat stored below
the surface.
Evaporation may be accomplished in special equipment
designed for this specific purpose, However; the process is
relatively expensive and is limited primarily to the recovery of
colatile by-products from waste liquids and to the treatment of
wastewaters where no alternate methods are available. This
discussion will be concerned with evaporation by natural environmental
effects.
The evaporation process in its simplest form consists of
providing shallow reservoirs and allowing the wastewater to be
detained until the transformation of the liquid to vapor has been
completed,
Design Considerations and Process Variables
! effective surface area
1, temperature of the water and of the air
3. the movement of air above the water surface
4, the relative humidity
5, nature of the wastewater
6, depth of the reservoir
-116-
-------
FIOITRE 31
LABORATORY ION EXCHANGE COLUMNS
-117-
BACKWASH
"' WASTE
DISTILLED
WATER
RESERVOIR
EFFLUENT
RESERVOIR
I" TUBE
EXCHANGE BED
GLASS BEADS
SCREEN
-------
7, salinity of the wastewater
8. concentration of surfactants or other evaporation
suppressants in the wastewater
9. precipitation
10. geographic location
Preliminary Investigation Requirements
The predictor equation mentioned herein was derived from
work conducted by the Bureau of Agricultural Engineering of the
United States Department of Agriculture (Rohwor, 1931). Many
other formulas have been proposed by different experimenters for
the determination of the rate of evaporation from free water
surfaces, but little information concerning evaporation of waste-
waters is available. However, basic design criteria can be
established by use of evaporation pans. The standard Weather
Bureau Class A Pan is the most widely used in the United States.
The Pan is filled to a depth of 8 inches and the water surface
level is measured daily for evaporation determinations. Other
measuring equipment should be available at the Pan site for
meteorological determinations and evaluation of other factors
contributing to evaporation.
Reverse Osmosis
Description of Process
A natural phenomenon known as osmosis occurs when solutions
of two different concentrations are separated by a semi-permeable
membrane ("Summary Report - Advanced Waste Treatment Research",
1962 to 1964). With such an arrangement water tends to pass through
the membrane from the more dilute side to the more concentrated
side. The driving force that imparts this flow through the membrane
is related to the osmotic pressure of the system, and this pressure
is proportional to the difference in concentration between the
two solutions. When pressure is applied to the more concentrated
solution, the flow of water can be retarded or even reversed,
i«-§-- > water moves from the more concentrated compartment to the
less concentrated compartment. The properties of a membrane that
permit water molecules to pass through but impede the flow of
contaminant molecules are not clearly understood, but membranes
composed of modified cellulose acetate prepared with various in-
organic additives exhibit this separability. The reverse osmosis
process provides an affirmative barrier to viruses, inorganics and
refractory organics, and removes unionized as well as ionized
materials.
-118-
-------
Reverse osmosis, which is a form of tertiary treatment,
should be preceded by additional treatment including filtration.
Secondary effluent is pumped under a pressure exceeding the
osmotic pressure into a high pressure vessel separated from a
collection vessel by a semi-permeable membrane. The product
water is collected on the low pressure side of the membrane,
usually at atmospheric pressure, and the concentrated brine from
the high pressure vessel is discharged to waste. Synthetic osmotic
membranes are available which can reduce the total dissolved
solids concentrations of saline feed waters from 50,000 mg/1 to
500 mg/1.
Design Considerations and Process Variables
1. water flux (gallons/square feet/day through the membrane)
2. membrane area, square feet/cubic feet
3. salt rejection, percent
4. operating pressure, psi
5C flow
6. total dissolved solids concentration of feed
7, acidity and fouling characteristics of waste
8. salt removal efficiency
Preliminary Investigation Requirements
Laboratory systems data are only parcially representative
of the performance of larger reverse osmotic systems. Membrane
surface area is smaller in laboratory systems and less likely to con-
tain imperfections. Flow regimes and patterns in the laboratory
desalination cell may differ from those present in larger systems.
Rejection increases with pressure and therefore comparisons
between laboratory and pilot plant performance may be misleading
if the operating pressures are not considered (Golf and Gloyna, 1969).
Process requirements may readily be determined from pilot plant
operation and with care, laboratory studies may be used to
evaluate the feasibility for such operations. Four types of
reverse osmotic units have been tested: plate and frame, spiral,
tubular, and hollow fine fiber, A tubular laboratory unit is
shown in Figure 32 .
-119-
-------
MEMBRANE MODULE
CONCENTRATE
TANK
EFFLUENT
FIGURE 32
LABORATORY TUBULAR REVERSE OSMOSIS UNIT
-120-
-------
Disinfection by Chlorination
Description of Process
Chlorination has long been considered to have the greatest
practical potential of all disinfection systems for freeing waste-
waters of pathogens (Rhines. 1968). Other agents have been proposed
for disinfection such as bromine and iodine. Ozone has been
effective for disinfection of water supplies and disinfection may
also be accomplished by the use of electromagnetic radiation.
Although chlorine is primarily used as a disinfectant,
its use may also be considered a form of tertiary treatment in
that residual organics are oxidized by free chlorine. As a result
of the strong oxidizing power of chlorine, this element will destroy
or inhibit the growth of bacteria and algae. Metal ions which are
in their reduced state react with chlorine and are also oxidized.
The type and amount of chlorine compound in solution is
pH and temperature dependent. Initially, chlorine added to waste-
water is reduced by compounds which react rapidly with the chlorine.
Finally, when all chlorine-reducing substances are oxidized in the
wastewater, the additional quantity of chlorine added to the water
results in an equivalent residual chlorine. The residual chlorine
is the form which is necessary for effective disinfection.
Chlorination may be accomplished by the addition of
gaseous chlorine or by the addition of calcium or sodium hypochloride.
Disinfection is time dependent and it is normally necessary to
provide a detention period of 20 to 30 minutes to provide effective
disinfection and also to account for short-circuiting in the
detention basin. Disinfection of a wastewater effluent is indicated
by a chlorine residual which may be detected in the effluent after
sufficient contact time.
Design Considerations and Process Variables
1, flow
2, hydrogen-ion concentration of the wastewater (pH).
3. extent of chlorine reducing compounds in the wastewater
A. form and concentrations of nitrogen compounds in the
wastewater
5. chlorine demand
6. chlorine feed concentrations
-121-
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7. contact time
8. temperature
9. nature and number of organisms in the water
Preliminary Investigation Requirements
Basic design criteria for disinfection by chlorination
can be established through laboratory techniques. The objective
of the laboratory procedure is to relate contact time, chlorine
dosage, and chlorine residual to effective disinfection. The
Coliform family of bacteria is normally used as an indicator of
contamination and their degree of removal may be related to disin-
fection efficiency. The contact time determined from the laboratory
procedure is normally increased to account for short-circuiting and
other difficulties encountered in actual plant operation. Waste-
water treatment facilities normally require between 3 and 15 mg/1
of chlorine for disinfection, and it is customary to carry a 1 mg/1
residual measure in the effluent after a 20-minute chlorine contact
period.
Rapid Sand Filtration
Description of Process
Rapid sand filtration can be used effectively to polish
secondary wastewater effluents. Rapid sand filtration may be
accomplished by gravity and under pressure, but gravity sand
filters handle large flows more economically.
The conventional rapid sand filter consists of 18 inches
of gravel overlain by 30 inches or less of sand. Natural silica
sand is a common filtering medium, but other fine grained filter
materials such as crushed anthracite have been used. The rapid
sand filter is normally rectangular in shape and reinforced con-
crete construction is commonly used for housing the filter beds.
The filter beds are underlain with a piped lateral collection
system and the installation is valved to permit backwashing and
to control the application of wastewater to the beds. Conventional
filters are operated at hydraulic loadings in thr range of two
to four gpm/ft^. Rapid sand filtration has been enhanced by the
use of multimedia filters incorporating, for example, sand-coal-
garnet beds and hydraulic loadings of four to eight gpm/ft^ are
commonly used in these multimedia beds.
-122-
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Design Considerations and Process Variables
1. flow rate
2. media grain size
3. filter depth
4. properties of suspended solids
5. temperature
6. use of chemical treatment and filter aids
f\
7. filter hydraulic loading, gpm/ft
8. allowable headloss to the bed
Preliminary Investigation Requirements
Rapid sand filtration is affected by a large number of
variables and at the present time, there is no accepted mathematical
model that correlates all the variables affecting the filtration
phenomenon.
In general, it seems that because so many variables
affect the removal of solids and sand filters, all of them cannot
be included in one filtration equation. Floe size, size distri-
bution, shape, composition and concentration, together with sand
size and shape, size distribution, rate of filtration, temperature,
etc., all play a part in determining the manner and extent to which
suspended solid removal is accomplished in a given filter layer.
Therefore, filter design still remains the "art of relaying past
experience to the prediction of filter performance" (Fox and
Cleasby,1966).
The rapid sand filtration process lends itself to pilot
plant study and many of the variables can be evaluated in the labora-
tory. Figure 33 illustrates a laboratory-sized rapid sand filtration
unit.
SLUDGE HANDLING AND DISPOSAL
Sludge dewatering and disposal is one of the more important
components of the total waste treatment system. Not only are large
quantities of waste solids accumulated daily, but the day-to-day
cost of sludge disposal frequently exceeds the cost of any other
single process in a wastewater treatment plant. Primary sludges
from refinery wastewaters are among the most difficult to handle
due to the presence of oils and emulsions.
-123-
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STAND
/rrr:
PRESSURE RELEASE VALVE
BACKWASH VALVE
EFFLUENT VALVE
MANOMETER
TUBE
MANOMETER
BOARD
FIGURE 33
LA;;G:LVTG:IY SAND FILTER
-124-
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Sludge handling and disposal includes concentrating the sludge
for process use, dewatering and processing the sludge for conver-
sion into a form suitable for disposal, transportation of the sludge,
and final disposal.
Characterizing sludge handling methods is extremely difficult
as two or more processes may be used conjunctively for one operation.
In the past, anaerobic digestion was widely practiced in the treat-
ment of primary sludges and thickened secondary sludges. However,
few anaerobic digesters are presently used in refinery or petro-
chemical wastewater treatment facilities. Mechanical dewatering
of sludges is being adopted by increasing numbers of cities and
industries due to increasing land and labor costs. Barging of
thickened sludge to the ocean is being practiced by municipalities
and industries near coastal areas, but this method may be restricted
in-the future. Sludge incineration, therefore, is considered the
process having the most potential ("A Study of Sludge Handling
and Disposal",1968).
Often sludge handling and disposal represents 25 to 50
percent of the total capital and operating cost of a wastewater
treatment plant and the volume of waste sludge will continue to
increase. Sludge handling and disposal is an integral part of the
total waste treatment process and required the same degree of
study given to other plant processes. Predictor equations may be
more difficult to derive for sludge handling operations; however,
through the use of laboratory and/or pilot plant equipment, basic
design criteria can be established.
Analyses helpful in characterizing wastewater sludges with
regard to handling and disposal are schematically presented in
Figure 34 . The sludge fractions are categorized as inorganic
and organic, with a suggested sub-categorization of the
organic component into its biological and non-biological
fractions. As the effects of benthic sludges, effluent suspended
sludges, and excess sludge for disposal are environmentally signi-
ficant, it becomes necessary to quantitatively and qualitatively
evaluate its biological composition.
The sludge handling and disposal treatment processes as
categorized in Table 17 are listed herein and are described in
terms of their treatability of preliminary investigation require-
ments.
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SLUDGES
(A) INDUSTRIAL
(B) MUNICIPAL
(C) BIOLOGICAL SYNTHESIS
(D) CHEMICAL
GENERAL CHARACTERISTICS
SPECIFIC GRAVITY
MLSS
MLVSS
SVI
SETTLING VELOCITY
SPECIFIC RESISTANCE
COEFFICIENT OF COMPRESSIBILITY
ORGANIC
Heovy
Metals
Alkaline Earth
Metals
Halogens
Nitrogen
a
Phosphorus
CALORIFIC CONTENT
(Btu /Ib VSS)
mg COD, TOC.TOD
mg VSS
J
Carbohydrates
a
Lignin
NON-
BIC
NOfv
BIOLOGICAL 8
)LOGICAL-
- ACTIVE
Alcohol
Sol-ible
\
A;coho
Insolubl
NON-BIO LOGICAL
Oil a Grease
(Ether Extractables)
TTC
jj moles TF .
l~ mg VSS '
1
mg BOD
7ng~VSS
1
Oxygen Uptake
mg Op / hr
( )
aerobic
1
DNA Cone
mg VSS
1
Plale Count
no cells
1 mg VSS '
I
Gas
Production
( Ib VSS '
anaerobic
FIGURE 34
ANALYSIS FOR SLUDGE CHARACTERIZATION
-126-
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Aerobic Digestion
Description of Process
Aerobic digestion is a process in which excess biological
sludge is aerated for long periods of time, resulting in the cel-
lular oxidation or destruction of volatile solids. The concepts
of this destruction are similar to those applied in the extended
aeration process, although the sludge age values are such that
a less viable and more inert sludge is prevalent.
If the bacterial cells are represented by the chemical
formula CsHyNC^, then the cellular destruction through aerobic
digestion is represented by: C5H7N02 + 502 ^ 5C02 + 2H20 + NH-j.
This occurs when substrate in an aerobic system is insufficient for
synthesis of energy, and the rate of destruction exceeds that of
growth. Primary sludges often are combined with excess activated
sludge, although the VSS destruction rate usually decreases as
higher food to microorganism ratios (F/M) prevail.
Design Considerations and Process Variables
1. nature and concentration of solids
2. solids loading
3. sludge age
4. oxygen and mixing requirements
5. environmental conditions (temperature, pH, etc. )
Preliminary Investigation Requirements
The applicability of digesting sludges aerobically will
depend on the nature of the sludge, the applied loading, and the
sludge age. If aerobic digestion is considered as a candidate
process in a waste treatment system, bench or pilot scale tests
should be undertaken to determine the VSS destruction rates and
oxygen requirements necessary for design purposes.
The destruction rates of digestible sludges can be
evaluated in the laboratory using batch reactors such as those
shown in Figure 22 . The sludge mixture is aerated and the
VSS measured at various periods of time. Once the VSS concen-
tration becomes stabilized, the degradable fraction can be estimated.
The data are>then plotted and the empirical relationship determined.
-127-
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The oxygen uptake rate of the sludge mixture is also
monitored throughout the aeration period. This rate at the aeration
time required for the desired VSS destruction level can then be
used in estimating the system oxygen requirements.
Anaerobic Digestion
Description of Process
The anaerobic treatment of wastewaters of digestion of
sludges involves a multitude of sequential biochemical reactions
whereby facultative and anaerobic microorganisms ultimately con-
vert organic material to carbon dioxide and methane. These reactions
basically involve the conversion of substances such as organics,
nitrates, and sulfates to reduced organics, carbon dioxide, methane,
ammonia, and hydrogen sulfide.
As the anaerobic conversion of various substrate materials
yields little energy to the microorganisms, only a small portion
of the waste is converted to new cells. This is an inherent
advantage of the anaerobic process in treating wastewaters, as large
volumes of sludge are not synthesized as in the aerobic process.
Other advantages include low nutrient requirements, no oxygen
requirements, and production of a useful product, methane.
Design Considerations and Process Variables
1. organic loading
2. solids loading
3. temperature and pH
4. acidity/alkalinity
5. hydraulic detention time and microbial growth rate
6. gas production
7. mixing
8. nature and concentration of solids
Preliminary Investigation Requirements
Anaerobic digestion and anaerobic treatment of liquid
wastewaters can be evaluated using bench scale units such as those
shown in Figures 35 and 36 or on a larger pilot scale.
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FEED TUBE AND
GAS SAMPLING COCK
MIXER*,
GAS
COLLECTION
TUBE
ASPIRATOR
BOTTLE
WITHDRAWAL
TUBE
ONE LITER
DIGESTER
FIGURE 35
LABORATORY BATCH-FED DIGESTOR
-129-
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GAS PUMP
FEED PUMP
GAS TO
WASTE
GAS REC1RCULATION
CONDENSATE
TRAP
1
DIGESTER
WITHDRAWAL
TUBE
\
J
)
\\
v////////////////////
ONE LITER
FEED BOTTLE
FIGURE 36
CONTINUOUS-FEED DIGESTOR
-130-
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The process conditions can be changed as required in
order to evaluate the corresponding process efficiency. It
should be recognized that operation and control becomes time
consuming and critical as the scale is increased.
Heat Treatment of Sludge
Description of Process
Heat treatment may be classified as a combustion process.
However, much lower temperatures are used in heat treatment than
used in the incineration process. The process may be expressed
in terms of a "pressure cooker system" and is known as wet air
oxidation. The process developed in Europe is known as the
"Porteous Process" and the American version developed by Zimmerman
is appropriately referred to as the "Zimmerman Process." In both
methods the feed sludge temperature is elevated by passage through
a heat exchanger and then the sludge is pumped to the reactor
where steam is added. The reactor temperature is maintained at
approximately 380°F. The wet air oxidation process differs from
the Porteous because of the addition of air and scrubbing of
exhaust gases in the former. Both systems require that the sludge
be ground to about .25-inch size particles and be pumpable.
Exposing the sludge to heat and pressure coagulates the
solids, breaks down the gel structure, and reduces the hydration
and hydrophilic nature of the solids. The liquid portion of the
sludge can then be separated for additional dewatering and final
disposal. Treating sludge, on leaving the reactor, passes through
the heat exchanger, giving up most of its heat to the incoming
raw sludge. After leaving the exchanger, the supernatant is
decanted from the solids. The thickened sludge is dewatered
further by one or more of several methods (Porteous ,1968).
Heat-treated sludge may be dewatered by filter presses or vacuum
filters or used for landfill.
The Zimmerman Process has effectively treated sludges
containing three to six percent solids without preliminary
dewatering; however, economics seem to justify prethickening.
Design Considerations and Process Variables
1. sludge flow
2. solids concentration
3. volatile solids concentration
4. chemical oxygen demand
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5. chemical efficiency, COD removal
6. power recovery desired
7- sludge variability
8. ultimate disposal method
9. nature and composition of sludge
Preliminary Investigation Requirements
The basic design criteria for heat treatment may be
determined by performing physical and chemical analyses of the
sludge. In a study covered by the United States Public Health
Service ("Ultimate Disposal for Advance Waste Treatment AWTR-3"),
it was concluded that data obtained from pilot plant studies
were not amenable to simple kinetics and relations should be
developed empirically for specific situations.
Thickening
Description of Process
Sludges from primary or secondary processes usually
require thickening prior to dewatering by air drying, vacuum
filtration, or centrifugation. If a sludge can be thickened,
the process offers the advantages of improving digester opera-
tion, reducing sludge volumes for direct land or sea disposal,
and enhancing the efficiency of process sludge dewatering
systems.
Biological sludges usually can be thickened to a
solids concentration of 4 to 6 percent, depending on the
type of thickener and the nature of the sludge. As the
ability of many sludges to thicken can be defined only in
general terms, bench or pilot thickening studies should be
initiated prior to finalizing the thickener design. Air
flotation, mentioned previously, is also used for sludge
thickening in certain applications.
Design Considerations and Process Variables
1. sludge loading
2. diameter and configuration of thickening unit
3. depth of thickener
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4. temperature
5. raking mechanism
6. detention time
7. sludge depth in thickener
8. general sludge characteristics
Preliminary Investigation Requirements
The most common approach in evaluating thickening
requirements for sludges is to use batch settling cylinders
such as the one shown in Figure 20.
The sludge in question is put into the batch settling
cylinder and the settling and thickening characteristics are
evaluated under quiescent conditions, serving as the basis for
scale-up and design (Eckenfelder and Ford, 1970; Edde and
Eckenfelder, 1967).
Lagooning
Description of Process
Lagoons may be divided into 3 classes: (a) thickening,
storage, and digestion lagoons; (b) drying lagoons; and (c)
permanent lagoons ("A Study of Sludge Handling and Disposal",
1968).
Lagooning is the most popular sludge disposal technique
at industrial wastewater treatment plants. Lagooning may be
considered as a stage process in the handling of sludge or as
a final sludge disposal process. The first type of lagoon is
used when conventional digestion units are overloaded or some-
times as substitutes for conventional processes. Drying lagoons
are used as substitutes for sand drying beds and a permanent
lagoon where sludge is never removed is one of the cheapest
methods of sludge disposal.
Permanent lagoons may be considered as a land filling
method of sludge disposal. A supernatant decanting system
enhances the operation of permanent lagoons by providing
additional storage. Sludge stored in lagoons may be dewatered
from about 95 percent moisture to 55 or 60 percent moisture in
2 to 3-year periods. The standard operating procedure for
permanent lagoons is to discharge digested sludge to the lagoons
at regular intervals, allowing a drying and cleaning period.
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Waste stabilization ponds can be used effectively to
treat excess activated sludge (Gloyna and Fisher, 1965).
Lagoons are often used for sludge dewatering prior to ultimate
disposal and in effect the lagoon acts as a gravity thickener.
When a lagoon is used for dewatering and not permanent storage,
recommended filling depths are 2.5 to 4 feet. However, ponds
5 to 6 feet in depth have been used to stabilize waste activated
sludge.
Design Considerations and Process Variables
1. available land area
2. climatic and atmospheric conditions
3. subsoil permeability
4. lagoon depth
5. lagoon surface loading
6. sludge characteristics
7. moisture content of sludge
Preliminary Investigation Requirements
Sludge lagoons have been designed on the basis of
surface or volumetric loadings or based upon ultimate disposal
requirements. Model ponds illustrated in Figure 27 have proven
useful in evaluating several variables of pond design. These
model ponds were developed for studies of waste stabilization
pond treatment of wastewaters, but can also be used to study
sludge stabilization. Development of design criteria is
dependent on lagoon type, _e._g., whether the process is to be
designed for thickening, drying, digestion or storage.
Sludge Drying Beds
Description of Process
Dewatering of digested sludge is commonly accomplished
by the use of open sand drying beds (Quon and Johnson, 1966).
Sewage sludge should be properly digested before application to
atmospheric drying as digestion enhances sludge drainability and
raw sludge may cause undesirable odors (Jennett and Santry, 1969).
Most beds are open and completely exposed, while others are glass-
covered to reduce the effects of inclement weather on the drying
process.
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Drying beds usually consist of 4 to 9 inches of sand over
8 to 18 inches of graded gravel or stone. Six to 12 inches of
digested sludge are applied to the bed and allowed to drain through
the sand beds where the filtrate is collected by underground
laterals, conveyed to sumps, and subsequently recycled through the
plant. Experiments have shown that tile-drained sludge beds dry
25 percent faster than beds with impervious bottoms. However,
other experiments and studies indicate that non-underdrained beds
can be built and operated at one-fifth the cost of a tile-drained
bed.
The sludge drying process incorporates drainage of the
sludge moisture through the bed and the simultaneous removal of
water by evaporation. The amount of moisture lost by evapora-
tion during the initial stages is insignificant but becomes very
important 1 to 2 days after the sludge is applied to the bed.
The sludge is allowed to dry until it reaches a
"liftable" condition at which time the dried sludge is removed
from the beds for final disposal. This condition normally
occurs when the moisture content is 70-80 percent.
The moisture content of the dried sludge is on the order of
60 percent.
Design Considerations and Process Variables
1. climatic and atmospheric conditions
2. depth of sludge application
3. presence or absence of chemical conditioning
4. sludge moisture content
5. source and type of sludge
6. extent of sludge digestion
7. sludge age
8. sludge composition
9. solids concentration when applied
10. sludge bed construction
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Preliminary Investigation Requirements
Only recently have attempts been made to formulate
rational design standards for sludge drying beds. In the past,
bed requirements have been based only on empirical relationships
or experience factors.
Investigators have attempted to derive design criteria
from laboratory experiements and pilot plant operations (Randall
and Koch, 1969). However, correlation between experimental data
and actual plant data has been relatively poor.
Selected variables of the sludge drying processes have
been successfully studied in the laboratory as well as on a pilot
plant scale (Carnes, 1966). Experimental units have also been
useful for evaluating the effects of chemical conditioning on
sludge drying.
Vacuum Filtration
Description of Process
Vacuum filtration is used to dewater wastewater sludges
in which water is removed under an applied vacuum through a porous
media which retains the solids. In the operation of vacuum
filters, a rotary drum passes through a slurry tank in which
solids are retained on the drum under an applied vacuum. When
the drum emerges from the slurry tank, the deposited cake is
further dried by the transfer of liquid to the air which is
drawn through the cake by the applied vacuum. The filter cake
is then removed to a collection hopper for hauling or incinera-
tion.
Design Considerations and Process Variables
1. sludge feed concentration
2. sludge conditioning (chemical additives)
3. degree of thickening preceding filtration
4. sludge viscosity
5. filtrate viscosity
6. operating vacuum
7. chemical and physical composition including
partial size, shape, etc.
8. type and porosity of filter media
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Preliminary Investigation Requirements
The most rapid means of estimating the vacuum filter
yield for a given sludge is by use of the leaf test apparatus.
The test variables such as an applied vacuum, sludge concentra-
tion, sludge conditioning, etc., are established and the sludge
yield for each condition is estimated (Eckenfelder and Ford,
1970). Continuous pilot scale tests are recommended if design
information for large and costly vacuum filtration installation
is required.
Centrifugation
Description of Process
Basically, centrifuges separate solids from the liquid
through sedimentation and centrifugal force. The most effective
centrifuges for dewatering sewage sludges are horizontal,
cylindrical-conical, solid bowl machines ("A Study of Sludge
Handling and Disposal", 1968).
In a typical unit, sludge is fed through a stationary
feed tube along the center line of the bowl to the hub of the
screw conveyor. The screw conveyor is mounted inside the
rotating conical bowl and rotates at a slightly lower speed than
the bowl. Sludge leaves the end of the feed tube, is accelerated,
passed through the ports of the conveyor shaft, and is distributed
to the periphery of the bowl. The solids are settled through the
liquid and are moved along the bowl wall by the blades ofxthe
screw conveyor. The solids move out of the liquid bowl and onto
a drainage deck on which they are continuously conveyed by a
screw to the end of the machine, at which point they are dis-
charged. The liquid effluent is discharged through effluent
ports after traveling the length of the pool under centrifugal
force. The depth of the liquid or pool volume can be varied by
adjustment of weir plates located at opposite ends of the bowl.
Centrifugation has been used for sludge thickening and
sludge dewateringj and has been used with and without chemical
conditioning or the addition of polyelectrolytes. The centrifuge
is most effective in recovering primary solids, and least effec-
tive when recovering waste-act'ivated sludge.
Design Considerations and Process Variables
1. feed rate
2. sludge solids characteristics
3. feed consistency
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4. temperature
5. chemical additives
6. bowl design
7. bowl speed
8. pool volume
9. conveyor speed
Preliminary Investigation Requirements
Unlike filtration, it is not easy to predict centrifugal
performance by the use of laboratory techniques. Pilot studies
must be made and appropriate scaling factors determined for
process design. When scaling pilot plant data to larger units,
it is necessary to consider the residence time of the liquid
in the bowl, the solids thickness and the residence time of the
solids on the beach, and particularly the effective centrifugal
force on the liquids and solids (Albertson and Guidi, 1969).
It may be possible to determine the feasibility of
centrifugation from simple laboratory tests. The sludge to be
dewatered may be spun in a laboratory hand centrifuge for 30
seconds at 2,000 rpm, and after centrifugation, the tube filtered
to determine the stability of the deposited cake.
Filter Press
Description of Process
Filter pressing presently is not widely practiced in the
United States, probably because of the high labor and maintenance
costs involved in the batch operation. However, the applicability
of filter pressing sludges is becoming more promising. The press
does not dewater solids by squeezing, but rather acts as a pressure
filter similar to a rotary vacuum filter with the exception that
higher pressures are used. Like the vacuum filter, the filter press
usually requires chemical conditioning, bench scale filtration
studies, and careful selection of the filtering media. Economics
of the process dictate sludge concentrating by some other means
prior to pressing.
The "Sludge All System" developed by Beloit-Passavant
Corporation is a completely automated process and the customary
shutdown for cake removal is not necessary. The system includes
thickening, pressing, and incineration; and the accumulated
filter cake from the press contains about 50 percent solids.
-138-
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Thickened sludge is ground prior to filtration and often
a precoat is added and mixed with the feed sludge before pressing.
The sludge enters the press through a center feed and is forced
into the filter modules. The filtrate is continuously pressed
through the fabric and discharged for recycle.
Design Considerations and Process Variables
1. sludge volumes
2. raw sludge solids concentration
3. nature of the sludge
4. chemical conditioning
5. ultimate disposal of filter cakes
6. filter pressing pressure
7. filter mesh aperture size
8. filter pressing time
Preliminary Investigation Requirements
The basic design criteria for sizing a filter press unit
can be developed by use of a pilot plant unit. Pilot plant data
should also provide thickening and chemical conditioning require-
ments. Means for ultimate disposal of the cake solids often will
dictate the required solids concentration in the final sludge cake.
A final cake solids of 40 percent may be expected in the sludge
cake provided feed solids are maintained near 10 percent.
Land Disposal
Description of Process
The disposal of liquid digested sludge on open land sur-
faces is quite common among smaller wastewater treatment plants.
In England, the disposal of liquid sludge to farmland is very
popular and in the arid and semi-arid parts of the United States,
the reclamation of water from municipal sewage is becoming in-
creasingly recognized as an important water conservation measure.
Liquid digested sludge and supernatant have been applied to lands
for final disposal to fertilize grass or agricultural crops for
soil conditioning. Digestion, aerobic or anaerobic, is almost
always required before spreading liquid sludge on land. Sludge
is distributed on the land and processed in a variety of ways.
The sludge may be injected into the subsoil under pressure or
simply pumped or gravity fed through a pipeline to agricultural
fields or land to be reclaimed. A common technique is disposal
directly to the land by spraying from tank wagons.
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Design Considerations and Process Variables
1. proximity of surface waters and distance to
groundwater table
2. toxic constituents of the sludge
3. nutritional value of the sludge
4. availability of disposal sites
5. transportation costs
6, suitability of soil for sludge disposal
7. nature of any aesthetic nuisance
8. effects on vegetation
9. application rates
10. atmospheric and climatic conditions
11. method of sludge application
Preliminary Investigation Requirements
Design criteria can only be developed through the use of
fairly large demonstration sites and extensive time involving studies
is required. The effects of land disposal on crops and ground and
surface waters is of paramount importance (Sosewitz and Hinsly,
1969).
Sludge Incineration
Description of Process
Various incineration processes have been applied to the
disposal of residues resulting from wastewater treatment. These
processes may be classified as multiple hearth fluidized bed flash
combustion and atomized suspension. The wet oxidation process
(classified previously under heat treatment) and incineration are
considered combustion processes. All these methods depend to some
extent on the organic material in the waste as a source of fuel.
However, regardless of the heat value of the sludge, some axuili-
ary fuel system is necessary during start-up of the incineration
process. The incinerator may be classified as an open flame water
evaporator since the actual incineration does not take place until
the sludge has lost most of its moisture through evaporation
(Sparr, 1968). The temperature in the burning zone must be at
least 1,350 to 1,400 F for complete combustion of the sludge
solids and for complete oxidation of the existing gases to
innocuous compounds,
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In the multiple hearth furnace, preconditioned dewatered
sludge is conveyed to the upper hearth of the furnace, and
mechanical rakes move the sludge from one hearth to the next
lower hearth, where the sludge is sequentially dried, burned, and
the ashes cooled.
In the fluidized bed incinerators, air is utilized to
maintain hot sand in an expanded or fluidized state. The violent
boiling of the expanded sand allows intimate contact of the sludge
and other fuel with oxygen without the aid of mechanical mixing.
Dewatered sludge is fed directly into the fluidized bed to which
preheated air is introduced.
The atomized suspension process is essentially a high-
temperature, low-pressure thermal process for the oxidation of
fine particles of sludge to innocuous ash. Sludge is concentrated,
ground, and sprayed as an atomized suspension into a stainless
steel cylinder. The walls of the cylinder are maintained at a
temperature between 1,000 to 2,000°F and heat is transferred
to the falling droplets of sludge by radiation. In the cyclone
flash dryer and incinerator process, dewatered sludge is mixed
with previously heat-dried sludge to produce a fluffy material.
In this form, it is carried through the drying stage by the high
velocity of hot gases and the dried sludge is burned in the
furnace.
Design Considerations and Process Variables
1. sludge flow
2. moisture content of sludge
3. volatile solids content of the sludge
4. heat value of the sludge
5. type of operation, continuous or intermittent
6. source and type of auxiliary fuel
7. method of final disposal of solid residue
8. sludge variability
9. sludge loading
10. possibility of alternate methods
Preliminary Investigation Requirements
Design criteria are established through incinerating the
sludge in a bench or pilot scale burner. The auxiliary fuel re-
quirements, nature of the ash, and composition of the off-gases
are the important parameters to be ascertained.
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Transportation erf Sludge and Sea Disposal
Description of Process
Sludge may be transported by rail, truck, barge, pipe,
or conveyor. For hauls up to 50 miles, it is likely that truck
transportation would be more economical than rail. Freight rate
structures in the United States are extremely diverse, causing
comparisons of transportation methods to be difficult at best.
In addition to the cost of hauling, there will be an incurred
cost for loading sludge into hopper cars in the case of rail
haul or pumping sludges to barges in the case of barge haul.
Barge rates are lower than rail rates since the tractive force
involved is less and barging normally does not bear the cost of
the waterway.
For coastal communities or communities adjacent to the
well-developed inland waterway systems on the Mississippi, Ohio,
Missouri, Illinois, and Tennessee Rivers, sea disposal is
frequently the most economical and simplest method available
for ultimate sludge disposal, although this entire concept is pre-
sently under review by the regulatory agencies. It should be
recognized that present and future laws governing sea disposal
practice will in large measure dictate its economics.
Design Consideration and Process Variables
1. proximity of final disposal site
2. pretreatment required
3. transportation unit costs
4. type of transportation available
5. distance to loading point
6. requirements for final disposal
7. sludge characteristics
Preliminary Investigation Requirements
The decision to use transportation in conjunction with
sludge disposal is based upon an analysis of alternate dewatering
and disposal methods. Laboratory analyses of the sludge are re-
quired for such an investigation. There are many factors that may
rule out the possibility of sludge transportation, such as the un-
availability of economical transportation or the distance to a
final disposal site. Barging and sea disposal should be considered
as a means for ultimate sludge disposal for plants located near
rivers close to the sea.
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ULTIMATE DISPOSAL
The final disposition of residual or refractory wastewaters
and sludges resulting from various processes is generally termed
"ultimate disposal."
Solutions to ultimate disposal problems include subsurface
storage, conversion of wastes to innocuous end products, storage
in ponds or land spreading, and ocean disposal. Land spreading,
lagooning, and ocean disposal processes have been presented else-
where and only deep well injection and thermal oxidation are dis-
cussed herein. These processes are further described in terms of
their treatability or preliminary investigation requirements.
Thermal Oxidation
Description of Process
The thermal oxidation of liquid wastewaters involves the
transfer of heat from an auxiliary fuel to the wastewater. In
some cases, the wastewater has calorific value which decreases
the total auxiliary fuel requirements.
The wastewater is first atomized as finely as possible
in order to present the greatest surface area for mixing with
combustion air. The temperature of the system is maintained at
a level necessary for the reaction to proceed and sufficient
residence time is provided to allow complete oxidation. The
system is also designed so that there is sufficient turbulence
for air, liquid, and fire contact.
The equipment normally consists of a horizontal or
vertical refractory lined furnace with an auxiliary fuel burner
firing at one end or tangential to a cylindrical shell. The size
of the incinerator depends on the heat release of the system, the
amount of combustion air to be used, and the quantity of wastewater
injected.
Design Considerations and Process Variables
1. flow
2. calorific value
3. residence time in burner
4. air flow
5. ignition temperature of organic material in
the wastewater
6. degree of wastewater atomization
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7- degree of system turbulence
8. auxiliary fuel calorific value
Preliminary Investigation Requirements
Before any liquid incineration unit is installed,
pilot scale studies should be undertaken. This requires that
representative samples either be obtained from the waste stream
or synthesized. The wastewater is then fed to the pilot liquid
incineration unit, atomized, and burned. The stack gases are
monitored for products of incomplete combustion while process
variables such as auxiliary fuel feed, wastewater pumping rates,
temperatures, etc., are varied as required throughout the test
series. The necessary design criteria then can be established
based on observed performance.
Deep Well Disposal
Description of Process
Subsurface disposal of liquid wastes is not a new
concept as the oil and gas producers have been using this method
for disposal of oil field brines for half a century. Only re-
cently have the process industries realized the applicability of
deep well injection for disposing of concentrated and relatively
untreatable waste streams. The depth at which these wastes are
discharged vary from a few hundred feet to over 2,000 feet and
well head injection pressures for some wells have approached
4,000 psi (Gloyna and Ford),
A suitable disposal formation is the very heart of a good
disposal system and if water can be disposed of with a vacuum on
the injection well head, operating expenses would be much less
than when injection pressures are required (API, 1960).
Deep well disposal requires the injection of liquid waste
into a porous subsurface stratum which contains noncommercial
brines. The wastes are merely stored below ground in strata
which are sealed by impervious strata, thus isolated from usable
underground water supplies or mineral resources. The disposal
system consists of a well and surface equipment, such as pumps
and pretreatment units.
Design Considerations and Process^ Variables
1. subsurface geology
a. permeability
b. porosity
c, fracture gradient
144-
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2. subsurface hydrology
3. fluid compatability
4. pretreatment considerations
5. flow
6. characteristics of waste, including temperature
Preliminary Investigation Requirements
Initially, a feasibility study is required which includes
acquisition of basic information concerning subsurface geology
and hydrology. Based on these data, the operating well head
pressure may be estimated and for steady-state single-phase flow,
the injection rate may be predicted, Pilot wells are often con-
structed prior to the design and construction of the waste
injection well system. Preliminary estimates of injection rates
and hole pressure may be verified by these pilot studies. These
studies are particularly important for the design of wastewater
pumps and appurtenances. The test hold will also serve to identify
subsurface geology and allow for sampling of the formation fluids.
The duplication of formation hydrologic and geologic conditions
in the laboratory is highly impractical and in most cases impossible.
Fluid compatability can be evaluated in the laboratory
by mixing the waste and formation waters and observing any changes
in the physical appearance. Preliminary investigations should
also include bacteriological analyses of the formation water and
wastewater as microorganisms may also cause plugging of the well
formation.
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COMPARISON OF LABORATORY AND PROTOTYPE TREA.TABILITY INFORMATION
It is important to know the aspects of using laboratory data
for the design of prototype units. Adjustment of laboratory data
to prototype units is often accomplished by the application of
"scale-up" factors which take into account the uncertainties involved
in the process operation and the variable environmental conditions.
Factors which should be considered in determining the scale-up
factors will be discussed herein.
Biological reactions can be considered to be unaffected by the
size of the unit (Eckenfelder and Cardenas, 1966). The biological
mass (MLVSS) requires the same amount of oxygen to decompose a unit
weight of contaminants in a BOD bottle as it will in a one million
gallon aeration tank, and the degradation of contaminants per unit
area of trickling filter slime will have the same potential activity
regardless of the size of the unit. The quantity of chemical additives
per unit volume of waste required to cause effective coagulation will
be the same whether the reaction occurs in a one liter jar or in the
actual industrial treatment plant. However, in all of these particular
cases, the desired reaction occurs only if the required reaction com-
ponents are thoroughly mixed for the required length of time.
The formation of hydrous microflocs during the initial rapid mix
phase of coagulation occurs in the first 0.1 seconds (Reddick, 1968),
but the actual design detention time for flash or rapid mixing is on
the order of 30 seconds. The difference between reaction time as de-
termined in the laboratory and the design time may be attributed to
difficulties in dispersing the chemicals in a large volume of waste-
water and the probability of the coagulant entering into undesired
side reactions.
The more significant problems which must be considered in apply-
ing laboratory treatability information to the design of prototype
units is summarized in Table 19. Sources of scale-up problems may
be categorized under (1) process considerations, (2) selected waste-
water characteristics, and (3) environmental factors. Perhaps the
most important process consideration is that of providing complete
mixing in each process unit for the designed length of time. One
investigator doubts whether more than 70 percent of a wastewater will
remain in a treatment unit for the designed length of time when the
detention period is based on the volume of flow and the unit volume
(Weber, 1969). Other studies have indicated that a maximum of 50
percent flow remains at t = V/Q in long narrow tanks. Recently com-
pleted flow studies at the Deepwater Pilot Plant in New Jersey,
sponsored by the Delaware River Basin Commission, participant in-
dustries, and the Environmental Protection Agency (EPA) indicated
the relative amounts of perfect mixing, plug flow, and dead space
that was occurring in each unit process using dye tracers. The
method applied proved to be very effective in evaluating the hy-
draulic characteristics of the neutralization tanks, reactor
clarifier, aeration basins, and the secondary clarifier (Wolf
& Resnick, 1963).
Although residence time is one factor which relates bench scale
and prototype responses, turbulence or "mixing intensity" is another
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TABLE 19
TREATABILITY PROBLEMS LEADING TO SCALE-UP FACTOR CONSIDERATIONS
I. PROCESS
A. Hydraulic Considerations - Short Circuiting in Completely
Mixed Systems
B, Inadequate Aeration in Aerobic Processes
C. Insufficient Contact of the Decomposing Media with Wastewaters
D. Adequate Dispersion of Chemical Additives
II. WASTE
A. Wastewater Variability
1. Flow
2, Chemical Contaminants (Organic and Inorganic)
3. Physical Contaminants
4, Temperature
B. Presence of Toxic Materials - Toxic Threshold
III. ENVIRONMENTAL
Temperature Surroundings
Possibility of Critical Plant Unit Failures
-147-
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one that has yet to be explicitly defined. Until significant parameters
characterizing turbulence can be developed, there will be certain un-
knowns involved in translating bench scale data to full-scale design
criteria. The expected variations in wastewater flow and composition
must be taken into consideration so that the treated effluent will be
acceptable for subsequent treatment and/or discharge into receiving
waters. Finally, the application of treatability results obtained under
constant laboratory conditions must be translated to one of varying
environmental conditions. Process operating characteristics obtained
from studies conducted at a constant 20 C will be very different when
subjected to temperatures as high as 35 C, which is common in the South-
west United States; or temperatures as low as -40 C, which are common
in the Northern United States, and commonly applied temperature cor-
rection factors may or may not be applicable.
Very little information on comparisons of operating prototype and
laboratory units is available. However, the results of several inves-
tigations indicate that laboratory treatability studies produce valid
and applicable information which may be translated into design criteria
for prototype units (Ford and Eckenfelder, 1966). Ford and Eckenfelder
(1966) compared the operating characteristics of laboratory scale con-
tinuous activated sludge units to prototype field units treating a
petrochemical wastewater. The laboratory units had aeration compart-
ment volumes varying from 36 to 9,6 liters; and the variables which
were to be compared with the field data at various loadings included
sludge volume index (SVI), oxygen uptake rate, bacterial activity
(dehydrogenase enzyme test), settling velocity, and COD removal. The
results of these comparisons indicated that the removal efficiencies
were reasonably similar in the laboratory and prototype units operating
in the activated sludge regime (Table 20). Information extrapolated
from the laboratory units indicated that the oxygen uptake rate at a
loading of 0.24 Ibs BOD/day/lb MLSS would result in an oxygen uptake
of about 8 mg 0 /hr/gm MLSS. The oxygen uptake rate measured in the
prototype unit at this loading was 9 mg 0 /hr/gm MLSS.
An analysis of the bench and pilot scale data for a combined re-
finery and petrochemical waste showed a similar correlation. The two
units were operated nonconsecutively at a loading of 0.24 (Ib BOD/day/
Ib MLVSS). The bench scale continuous units, operating with an aeration
chamber volume of six liters showed an average BOD removal of 97 percent,
with an average oxygen uptake rate of 10.4 mg 0 /hr/gm MLVSS. The pilot
scale unit, operating under similar environmental conditions with an
aeration chamber volume of 54,400 gallons, exhibited a BOD removal of
89 percent and an average oxygen uptake rate of 7.2 mg 09/hr/gm MLVSS.
The lower efficiency of removal for the pilot plant can oe attributed
to operational difficulties as well as batch dumps of inhibitory sub-
stances within the refinery & petrochemical complex during this period
of operation.
In any comparison between laboratory and pilot units, differences
in operational efficiencies can be expected. Differences in the
mixing intensities, fluctuating influent feed concentrations, hy-
draulic short-circuiting, and problems relating to sample
collection can allude to poor correlation. Based on
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TABLE 20
COMPARISON OF AVERAGE ACTIVATED SLUDGE OPERATIONAL VALUES FOR
BENCH SCALE AND PROTOTYPE UNITS
Lf
, Ibs BOD/ days
^ Ib MLSS
0.10
0.17
0.39
0.40
0.58
0.83
0.96
1.60
2.30
Prototype 0.24
Data
(Eckenf elder and
SVI Oxygen Uptake
(mg02/hr/
gm MLSS )
164 5
96 6
84 11
13
110 24
31
480 55
65
78
130-150 (9)
Ford , 1968)
Dehydrogenase
Enzyme
, moles ..
mg VSS
.021
.023
.032
.038
.025
.064
.035
.060
.105
.023
COD
Removal
(%)
73
72
69
68
60
61
52
54
50
(78-84)
Zone
Settling
Velocity
(ft/hr)
6.5
14.5
20.0
13.0
.30
nil
nil
-
NOTE: Temperature of Aeration Basin, Bench Scale Studies: 23 C
Temperature of Aeration Basin, Prototype: 34 C
-149-
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this recent experience, the organic removal observed in pilot
facilities is slightly less than that obtained in bench scale
units. The magnitude of this difference will depend on the
nature and "representativeness" of the wastewater, the degree
of mixing, and operational factors.
AERATION
The rate of oxygen transfer into wastewaters is one of
the most important design considerations in all high rate
aerobic biological treatment processes. At the present,
there is no commonly accepted method for designing full-scale
aeration units from data obtained on bench scale experiments.
However, recent information indicates that at lease one approach
would yield a scale-up method that would be applicable to all
types of aeration processes. This approach involves determining
both the mixing characteristics of an aeration device and the
relationship between the overall oxygen transfer to a common
substance such as tap water. The turbulence caused by an aeration
device can be related to the characteristics of the liquid and
the mixing device by the Mixing Reynolds Number. By definition
this number is equal to the ratio of inertial forces to viscous
forces (Mancy and Okum, 1965) and is expressed as follows:
inertial forces
Re viscous forces
where:
d = the length of the agitating mechanism
N = the number of revolutions per unit time
p = the liquid density
v = the viscosity
Since various components of wastewaters affect the efficiency of
oxygen transfer, it is necessary to relate the transfer capacity
to a common factor. This has been done by using tap water and
determining the
-------
GRAVITY THICKENING
One of the most common methods of concentrating wastewater
sludges is by the sedimentation process called gravity thickening.
Laboratory development of data for the design of this unit is
usually dependent upon simple batch settling tests performed in
1 liuer graduate cylinders. It has always been accepted that
this method is subject to a multitude of errors but that it was
the only feasible approach. Edde and Eckenfelder (1967) studied
the relationship between simple 1 liter batch settling tests and
the operation of continuous prototype thickeners. A mathematical-
model was developed which related a constant (CD) to the initial
sludge concentration, the underflow sludge concentration and the
mass loading. The value of this constant was determined for
several prototype continuous flow units (CDt) and compared to
the value obtained in the 1 liter batch settling tests (D^).
It was found that the ratio, Dt/Db, was closely related to the
sludge blanket depth in the prototype thickener. The relation
between the ratio Dt/D^ and the sludge depth is shown in
Figure 37. The authors concluded that once Dfc is determined
from bench scale batch settling curves the prototype operating
Dt may be determined from the ratio of Dt/D^.
ACTIVATED CARBON ADSORPTION
Adsorption of organics on activated carbon is rapidly
becoming one of the most successful advanced wastewater treat-
ment processes, and in some instances represents a favorable
economical alternative to biological treatment (Hager and
Reilly, 1969; Zanitsch and Morand). Two bench scale methods
are commonly employed to determine the design parameters for
this prqcess: 1) adsorption isotherm development tests, and
2) continuous flow column tests. Briefly, the isotherm method
consists of a batch test where the adsorption capacity of a
given type of activated carbon is determined by exposing a
small measured weight of the carbon to a volume of between 100
and 500 ml of the wastewater. The columns are usually built
on a large scale requiring several weeks of continuous opera-
tion and several thousand gallons of wastewater.
Because of the difficulty in constructing and operating
columns, batch tests to determine adsorption isotherms are often
employed. However, it has been concluded in some studies that
adsorption isotherms are of little or no value in determining
the organic carbon removing capacity for waste treatment
applications. There are many specific problems inherent in
scale-up of adsorption isotherms to prototype units. This
method is useful when dealing with solutions containing only
a few organic species. In most wastewaters there are many
organic species and the concentration of these organics is
constantly changing. The adsorption isotherm does not account
for other mechanisms which remove organics from wastewaters
in activated carbon filters. Factors such as biological
-151-
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1.0
0.9
0.8
0.7
0.6
0.5
0.4
Primary & Mixed Liquor Sludge
Primary Sludge
Primary Sludge - Third Study
D Value from Thickener
D Value from 1-liter Cylinder
Ave Sludge Depth is the Volume
of Sludge in 'the Thickener
Divided by its Surface Area.
I
I
2468
SLUDGE DEPTH (FT)
10
FIGURE No. 37
EFFECT OF SLUDGE DEPTH IN THICKENER AS A DESIGN PARAMETER
-152-
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activity in the carbon beds, filtration of suspended matter and
blending of multiple bed effluents all tend to provide higher
removals than would be indicated from adsorption isotherms de-
rived from batch tests.
Thus, rather than applying a "scale-up" factor in adsorp-
tion studies, a "scale-down" factor must be used since bench
scale tests generally underestimate prototype performance.
Because of the dependence of adsorption on the size of the
activated carbon, the characteristics of the wastewater studied,
and other experimental conditions, it is impractical to deter-
mine a common scale-down factor that may be used for prototype
design. However, the following example indicates the order
of magnitude of scale-down when similar wastewaters are tested
under similar conditions (Zanitsch and Morand). Small bench
scale adsorption isotherms were used to study the removal of
soluble organics from the effluent of a conventional activated
sludge unit. Column studies were initiated at the plant site
using 4 separate 4-inch diameter columns connected in series
with a total depth of 18 feet. These columns were operated
continuously for 31 days at an average flow of 320 gallons per
day. A pilot plant of 0.3 mgd capacity was Utilized to complete
the comparative carbon adsorption studies. The plant was opera-
ted under loading conditions similar to those used in the
column studies. Results of these investigations are reported
below:
Adsorption Capacity
Ib organic adsorbed
vr _u j TT^-I- j 100 Ibs Activated Carbon
Method Utilized
1. Bench scale batch analyses 3
2. Continuous flow columns 14
3. Prototype 35
The prototype units were about 2.5 times more efficient as the
continuous flow laboratory units. The "scale-down" factor in
this case of laboratory batch scale to laboratory continuous
scale to prototype unit was: 10:2.5:1; thus the importance of
estimating these factors for each waste treatment situation is
underscored.
CHEMICAL COAGULATION
The results of one study showed pilot scale chemical co-
agulation units to be more effective than the larger prototype
facility (Schindler, 1951). In this particular study, the
pilot plant which was one-seventh the size of the prototype
facility, was operated as a lime coagulation unit process for
the removal of white oils and sulfonates from a refinery ef-
-153-
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fluent. The 2 units were compared under similar loading condi-
tions and the optimum lime dosages were 1.05 tons per 100,000
gallons and 0.7 tons per 100,000 gallons for the pilot and
prototype plants respectively. In this case, the scale-down
factor was equal to 0.7.
It is emphasized at this point that bench or pilot scale
studies should be continuous reactor studies when the resultant
data is to be translated into design criteria for continuous
flow field units. Scale-up factors, such as they are, are
easier to predict and their magnitudes are closer to unity and
less fluctuative than those resulting from batch studies.
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MANPOWER AND TIME REQUIREMENTS
The implementation of water pollution control programs has
not kept pace with modern technological developments for 2 reasons
(U. S. Senate, 1969):
1. an effective system for forecasting the supply and
demand of the various categories of operator,
technician, and professional level personnel needed
in the water pollution control effort has been
lacking; and,
2. lack of the above system has resulted in a shortage
of treatment plant operators and of training oppor-
tunities to improve the necessary skills.
There is no doubt that present technology has the potential for
alleviating or eliminating many of the prevalent water pollution
problems. Placing adequately trained personnel at key positions
in pollution control programs is the most direct and efficient
way of achieving increased pollution abatement. The manpower and
time requirements for planning and executing wastewater surveys,
wastewater characterization studies, in-plant improvements and
treatability studies are summarized herein.
The time requirements and the quality of the personnel
necessary to complete a treatability study for any given in-
dustry will vary widely with the size of the industry and the
complexity of its wastewaters. Because of the diversity of
the problem, very few data are available concerning the actual
requirements of treatability studies. However, the skills and
experience needed to conduct treatability studies are similar
to those required of personnel charged with supervisory and/or
operational responsibility for water pollution control facili-
ties and information is available in these areas (Anon, 1968).
A study was recently completed on the identification of the
needs and problems of operational personnel responsible for
operation of municipal and industrial wastewater treatment
facilities. Particular attention was paid to the requirements
necessary to perform specific task functions, and the total
educational experience was related to the full time equivalents
required to satisfactorily operate and maintain a treatment
facility. The needs for task functions varying from those of
operations, maintenance, evaluation, and supervision of
treatment facilities were considered (Anon, 1968).
Treatment facilities surveyed in the time and qualifica-
tions study included operating petrochemical and refinery
industries with the following treatment units:
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Pre or Preliminary ^Secondary ^___ Sludge Handling
API Separators Deep well injection Centrifugation
Neutralization Filtration Digestion
Equalization Activated Sludge Thickening
Coagulation- Extended aeration Filtration
precipitation-
sedimentation Waste Stabilization Landfill
ponds
Incineration
The major responsibilities and time-consuming duties
generally increase with the number of different unit processes
and wastewater flows. These requirements for 4 industries are
summarized in Table 21. The full time equivalents (FTE)
represent the number of man days required to complete the task
function per 8-hour shift. For example, if 1.5 FTE are required
to complete a task, this means that a total of 12 man hours must
be utilized during each 8-hour shift to satisfy this task function.
These personnel requirements were ascertained through
personal communication and questionnaires with the industries
cited. The industries were selected to represent a broad
spectrum of treatment facilities, and the delineation of
personnel requirements for primary and secondary treatment
and sludge handling were based on extensive discussion con-
cerning the allocation of operating time to each of the unit
processes.
The various task functions and the education required for
the operation of all wastewater abatement facilities are listed
in Table 22. The task of planning and conducting treatability
studies requires personnel with qualitifications equivalent to
those listed under Area V of Table 22, while support personnel
may be drawn from the remaining categories.
A meaningful wastewater study will be contingent upon the
successful completion of the sequential process outlined in
Figure 38 . Many industries maintain a staff of consultants
qualified to administer water pollution control programs and
conduct or supervise wastewater surveys and treatability
studies. However, smaller industries cannot afford an internal
staff of pollution control experts and they must turn to con-
sulting firms, universities and colleges, regulatory agencies,
and other organizations involved in water pollution control for
assistance. Care must be exercised in choosing a consulting
engineer since all engineering firms are not equipped to per-
form or supervise treatability studies.
-156-
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TABLE 21
SUMMARY. PERSONNEL REQUIREMENTS FOR A 24-HR. WORKDAY
Operators, Laboratory Technicians,
Maintenance, Instrumentation,
Refinery #1
(Combined
Refinery #2
Refinery #3
Refinery #4
Primary
Treatment
FTE*
Chemical) 1.03
1.79
2.05
11.75
and Controls
Secondary
Treatment
FTE
4.08
-
1.45
9.70
Sludge
Handling
FTE
-
0.47
0.35
0.50
Supervisor
FTE
1.30
0.49
0.92
2.70
Total
FTE
6.41
2.75
4.77
24.65
Flow
MGD
15.60
3.02
4.61
6.05
* Full-Time Equivalents
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TABLE
TASK FUNCTIONS AND EDUCATIONAL EXPERIENCE NECESSARY FOR
EFFECTIVE OPERATION OF POLLUTION CONTROL PROGRAM
Area
Task Function
Definition of Task
Formal
Education Reqd.
Specialized
Training Reqd.
I Operations
a. Unskilled
b. Skilled
II Laboratory
a. Technician
b. Detailed
analysis and
plant control
III Maintenance a. Unskilled
b. Skilled repair
IV Instrument
and
Controls
a. Routine
b. Operations
and
Controls
Routine operations
Process control;
intermediate
decision making
Routine analysis
Calculations and
evaluations
Routine mainten-
ance
Repair and re-
placement of
complex equip-
ment
Routine cleaning,
reading and
maintenance of
instruments
Installation and
maintenance of
complex instru-
ments and
controls
Less than H.S.'
H.S£ or more
H.S.*
College or
Equal
On the Job
Operator Training
On the Job
Short courses
Less than H.S.* On the Job
H.S.* plus ap- Short courses
prentice
experience
H.S.-
Special Short
Courses
2-Year Tech- Special Manu-
nical School facturers'
Courses
-158-
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TABLE 22 (Cont)
TASK FUNCTIONS AND EDUCATIONAL EXPERIENCE NECESSARY FOR
EFFECTIVE OPERATION OF POLLUTION CONTROL PROGRAM
Area
Task Function
Definition of Task
Formal
Education Reqd.
Specialized
Training Reqd.
V Supervision a. Para-profes-
(operations) sional
b. Professional
c. Managerial
Shift operations
foreman
Runs plant with
broad decision-
making ability
H.S.* plus
College, addi-
tional specia-
lized schools
and/or masters
degree
Runs sanitary College and
district or specialized
industrial utility courses
department
Operators
training school
Short courses,
FWPCA courses,
industrial
managerial and
technical
courses
Specialized
courses
* High School
-159-
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!3
O
W
w
Pi
TREATMENT
RECOMMENDED
TREATABILITY
STUDY
EXECUTION
WASTEWATER
SURVEY
O
M
H
W
§
PLANNING OF
TREATABILITY
SURVEY
DISCUSSION WITH
QUALIFIED
CONSULTANT
SOURCE
PROBLEM
RECOGNITION
FIGURE 38
SEQUENCE OF EVENTS IN A TREATABILITY STUDY
-160-
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Many of the tasks related to a treatability study may be ac-
complished by the industry's personnel and if sufficient equipment
and space are available, the consultant may need only to supervise
the study and translate the data into design criteria. The industry
must fully understand the time requirements and competence levels
required to complete the study and this understanding should be
reflected in the man-hours allotted to in-house personnel involved
in the study. Delays in the treatability study pha§e will lead to
delays in design and construction and could precipitate problems
with the local citizenry or regulatory agencies.
The university graduate student specializing in water resources
or pollution control represents a valuable source of manpower for
industry.
An estimate of treatability study time requirements is pre-
sented in Table 23. Data shown in the table have been developed
from actual studies of refinery wastewater conducted by a private
consulting firm (Engineering-Science, Inc./Texas, 1970). The time
requirements have been categorized by task and presented with
respect to wastewater flow and refinery capacity.
Many factors may affect the time required to complete a task
related to the treatability study. For instance, should a pilot
scale plant be incorporated into the study, additional time will
be required for construction and operation of the unit. A suit-
able acclimation period will be required before meaningful opera-
tion data may be collected from a biological pilot plant. But,
on the other hand, acclimation would not be required should a
physical or chemical treatment process unit be utilized.
TRENDS IN TRAINING
The critical shortage of personnel trained in the field of
wastewater treatment has resulted in many state and local agencies
conducting water pollution on-the-job training courses.
A formal apprentice program has been established in Cali-
fornia by the Orange County Sanitation District (Harper, 1969).
This program was designed to train and develop personnel to
operate and maintain wastewater treatment and disposal facilities.
The program has been established for high school graduates 25
years old and younger, and consists of 2 batterys of 2 years each.
The first 2 years consist of familiarization of the trainee with
the overall treatment plant operation, and the second phase con-
sists of developing the special skills necessary to understand
the mechanisms of wastewater treatment.
A recently completed study of pollution control personnel
requirements suggested that the acquisition of competent manpower
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TABLE 23
MINIMUM TIME REQUIREMENTS FOR COMPLETION OF ALL TASKS
IN TREATABILITY STUDIES
(Full-Time Man-Day Equivalents)
Industry
Size
Tasks
Total
Waste- Waste In- Man-Day
water (1,000 Waste water Plant Treat Equiva-
Flow bbl/ water Character- Consid- ability lents
(MGD) day) Survey ization eration Study Req'd.
0.4
0,4-2.8
2.8-5.0
5.0
10
10-49
50-100
100
8.0
16.0
16.0
40.0
20.0
20.0
40.0
120.0
8.0
8.0
20.0
28.0
60
80
120
200
96
124
196
388
-162-
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depends on the following 3 related factors (U. S. Senate, 1969):
1. availability of adequate training opportunities;
2. the establishment of higher pay, advancement
opportunities, increase in job prestige; and,
3. determination of whether mandatory operation
certification is necessary and feasible.
As a result of this study, the Federal government is now actively
supporting many training programs in cooperation with governmental
units, educational institutions and other organizations to pro-
vide facilities to support Item 1 listed above.
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COSTS OF WASTEWATER TREATABILITY STUDIES
Between 1962 and 1967, $36.8 millions were spent for wastewater
treatment facilities in the oil refinery industry and it is estimated
that an additional $34 million will be spent on improvements to refinery
wastewater treatment facilities during the period 1967 through 1970. It
is estimated that it would cost in excess of $156 million to replace the
existing wastewater treatment facilities in the oil refinery industry
alone ("Report on Air and Water Conservation Expenditures of the
Petroleum Industry in the U.S.," 1968; Anon, 1968).
The cost of removing approximately 85 percent of the BOD from
wastewaters presently discharged from organic chemicals industry has
been estimated from $228 million to $341 million for the year 1970
(Projected Wastewater Treatment Costs in the Organic Chemicals
Industry, Rice and Company, 1968). The present level of waste treatment
expenditures were not cited. It should be noted, however, that the
production and sales of organic chemicals are expected to increase
approximately 52 percent over the 1968 production level by the year
1973 (Petrochemical Effluents Treatment Practices, Report No. 12020 -
2/70, FWQA). Based on the implementation of more stringent water
effluent criteria, the cost of treating the increased wastewater dis-
charges will climb accordingly.
Comprehensive treatability studies conducted by well-trained
competent personnel can provide optimum process design information
resulting in plant construction economy. Obviously, the successful
implementation of the overall water pollution control program requires
a treatability study of sufficient scope to investigate several alterna-
tives, the number of which will depend upon the complexity and number
of plant waste streams.
Recent trends indicate that present emphasis on low substrate
limited biological treatment will be shifted to high rate non-substrate
limited processes, requiring physical-chemical means of wastewater
treatment in the future. The use of physical-chemical methods is pri-
marily predicated on the trend toward reduced land requirements and
provisions for increased treatment efficiency. However, biological
secondary treatment combined with tertiary treatment, where required,
will continue to be the most economical solution for the majority of
petrochemical and refinery wastewater treatment problems.
The City of Cleveland, Ohio, has decided to investigate the feasi-
bility of providing wastewater treatment through the use of physical
and chemical processes. This approach has been dictated by the un-
availability of additional land for plant improvements needed for
secondary biological treatment of domestic wastewaters which presently
receive only primary treatment. In the case of Cleveland, real estate
constraints rather than biodegradability limitations have influenced
the particular design approach.
In contrast, a pilot-sized biological treatment facility has been
constructed to investigate the feasibility of treating the combined
wastewater flows of more than 14 industries located along the Delaware
-164-
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River. The pilot plant design was preceded by bench scale treatability
studies, the results of which indicated that biological treatment was
possible and the treated effluent would meet present criteria. Based
on the magnitude of the project, a pilot plant, hydraulically designed
for 50 gpm, was constructed using the bench scale data in the design
formulation. The treatability study approach applied on a bench
scale was repeated using the pilot plant in order to confirm and refine
bench scale data as well as to determine and evaluate operational prob-
lems, system response to operating and environmental variations, and
effluent quality. This study is being financed jointly by the partici-
pating industries and the Environmental Protection Agency (Project
No. 11060-DRO). The Delaware River Basin Commission is the administering
agency and Engineering-Science, Inc., is the project engineering company
(Engineering-Science, 1969).
The aforementioned examples demonstrate the need for treatability
studies prior to the design of wastewater treatment facilities. Bio-
logical treatment should be investigated initially, but the unavailability
of land and/or the characteristics of the wastewater may dictate the use
of alternate treatment processes. This discussion alludes to the neces-
sity of long-range pollution control planning and the conjunctive im-
plementation of treatability studies and in-plant optimization of water
use and product recovery which should result in a net savings in pollu-
tion control equipment.
Estimated costs for conducting treatability studies as discussed in
this section are presented with regard to wastewater analyses, personnel
requirements, and plant wastewater flows.
WASTEWATER ANALYSES
Numerous analyses are required for wastewater characterization and
effective monitoring of bench or pilot scale treating units. These
analyses may be limited to pH, dissolved oxygen, oxidation-reduction
potential, and TOG in the case of judging the performance of a model
waste stabilization pond. They may include organic analyses such as
TOD, COD, BOD,., oxygen uptake, spectroscopy, chromatography, volatile
solids, etc., in the case of monitoring the removal of petrochemical
contaminants in a pilot-activated sludge plant. It is not practical
for many industries to maintain elaborate laboratory facilities equipped
to perform all analyses needed in a treatability study, and it has been
common practice to subcontract all or a portion of the laboratory work
to dependable commercial laboratories.
The costs for laboratory services will vary from place to place,
and the unit costs are normally dependent upon the number of analyses
requested. A typical schedule of average laboratory unit costs as
obtained from several commercial laboratories is presented in Table
24. Special discounts are normally available for contract work or
where a large number of samples are submitted for analysis. In
medium to large surveys where the number of analyses run into the
hundreds and thousands, the unit costs may be decreased to less than
one-tenth of that shown in Table 24.
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TABLE 24
COSTS OF CHEMICAL ANALYSES OF WASTEWATERS
Analysis
Cost Per
Analysis
Immediate Oxygen Demand
Biochemical Oxygen Demand, 5-D,ay
Biochemical Oxygen Demand, 20-Day
Chemical Oxygen Demand
Total Organic Carbon
Ammonia Nitrogen
Nitrite Nitrogen
Nitrate Nitrogen
Total Kjeldahl Nitrogen
Suspended Solids $10.00, Plus Volatile
Total Solids $10.00, Plus Volatile
Settleable Solids
PH
Chloride
Sulfate
Phosphate
Hardness
Color, Water Method
Color, Wastewater Method
Turbidity
Petroleum Extract (Fats - Grease)
Alkalinity, Phenolphthalein and Total
Most Probable Number
Phenol
$ 10.00
15.00
20.00
15.00
10.00
4.00
4.00
4.00
30.00
12.50
12.50
2.00
1.00
4.00
4.00
5.00
4.00
3.00
25.00
2.00
10.00
5.00
30.00
15.00
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MANPOWER COSTS
Labor costs for conducting treatability studies are diffi-
cult to estimate as the number of man days required to fulfill
each task of the study is dependent upon the competence level of
the personnel and the scope of the study. Labor costs categorized
by competence level are presented in Table 25 . The widest varia-
tion occurs at the highest consultant level ($250 to $500 per day),
primarily because of the wide range of experience and ability
available at this level. Consultants should be retained only when
the pollution problems require special expertise that is not avail-
able in the industry or cannot be provided by closely associated
personnel. Generalized costs for treatability studies have been esti-
mated based on information presented in Tables 24 and 25 and are
shown in Table 26. Information concerned with time and cost
requirements for treatability studies is based on "judgement"
estimates made by engineers with consulting experience ip the
refinery and petrochemical industries. Thus, it is felt that
this information reflects the general requirements necessary to
complete comprehensive studies. However, extreme caution should
be taken in applying these overall averages to any particular
situation since special problems may increase time requirements
at any expertise level.
The additional cost to an industry for a wastewater survey
will depend on the number of steps that are necessary to complete
the study (Figure 38 ), using other than in-house personnel.
An estimate of the fraction of treatability costs alloca-
ted to labor is presented in Table 27. These data are based on
information shown in Table 25 and the costs have been categorized
according to wastewater flow.
COSTS OF PREVIOUS TREATABILITY STUDIES
The total cost of any treatability study depends on the
quantity and quality of the wastewater flow, size of the indus-
trial staff associated with the pollution abatement program,
length of study, level of experience, competence of personnel
contracted to complete the study, and other factors which are
unique to each industry. Therefore, it is difficult to predict
exact costs of studies performed on a particular wastewater.
However, close examination of previously conducted studies may
prove helpful in determining costs for future studies.
A tabulation of treatability study costs has been pre-
pared and is presented in Table 28. Costs shown in the Table
include laboratory analyses and labor, but are exclusive of
profit and overhead. Work covered by these studies included
wastewater characterization, biodegradability screening, labora-
tory-scale biological reactor operations and monitoring of
reactor contents, and a final report of the findings and recom-
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TABLE 25
LABOR COSTS INVOLVED IN TREATABILITY STUDIES*
Classification
Responsibilities
Per Day
Per Hour
1. Special Consultants
2. Supervising Engineers
and Scientists
3. Engineers and Scientists
4. Project Engineers and
Scientists
5. Specialists
6. Supporting Services
Overall Planning and $250-500
Consultant to project
Overall operation, planning, 180-250
and analysis
Detailed planning and 150-200
analysis
On the job supervision 100-150
and operation
Implementation of 100-150
operation
Assists study operator 50-80
$32.50-62.50
22.50-32.50
18.75-25.00
12.50-18.75
12.50-18.75
6.25-10.00
* These figures include salary costs and ordinary overhead. Applicable expenses
for travel and lodging, communications, report preparation, and printing are
reimbursable at actual cost plus 10 to 50 percent.
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TABLE 26
GENERALIZED COSTS OF TREATABILITY STUDIES'
Waste-
water
Flow
0.4 MGD
0.4-2.8 MGD
2.8-5.0 MGD
5.0 MGD
Waste-
water
Survey
850
2400
2400
6000
Waste-
water
Character-
izations
3000
3000
6000
18,000
In-
Plant
Consid-
erations
850
1200
3000
4200
Treat-
ability
Studies
9700
12,000
18,000
32,000
Total
14,400
18,500
29,400
60,000
*1
"Average personnel cost taken as $150/day.
of special equipment.
"Survey of major streams only.
Costs exclude purchase
* * * * * * * * *
TABLE 27
FRACTION OF COST PAID TO PERSONNEL IN TREATABILITY STUDIES
Total Cost(Percent
Class if ication
Wastewater
0.4 0.4-2.8 2
Flow
.8-5.
of Total)
(MGD)
0 5.0
1.
2.
3.
4.
5.
Special Consultants
Supervising Engineers & Scientists
Project Engineers & Scientists
Specialists
Supporting Services
10 10
5 10
40 40
5 10
40 30
10
10
50
10
20
10
20
50
10
10
-169-
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TABLE 28
COSTS OF COMPLETED TREATABILITY STUDIES
Study Wastevater Flow
Number Classification (MGD)
1 Organic Chemicals 1.5 1.
Methanol and Formalde- 2.
hyde Production
3.
4.
2 Organic Chemicals 1.0 1.
Butadiene Olefln, 2.
Styrene Production
3.
4.
5.
6.
7.
Study Length
Scope of Study (months)
General Wastewater Characterization 6
Biological Process Simulation
a. Continuous Reactors (Act. Sludge)
b. Batch Reactors (Act. Sludge)
Sludge Settling Analyses
Oxygen Transfer Analyses
General Wastewater Characterization 12
Biological Process Simulation
a. Continuous Reactors (Act. Sludge)
b. Continuous Reactors (Waste
Stabilization Ponds)
Sludge Settling Analyses
Oxygen Transfer Analyses
Microscopic Analyses
Chemical Coagulation Analyses
Bioassay Analyses
Analytical Tabulation
Analysis
COD
R/tn
TSS
VSS
NH - N
TKN
N03 - N
P04
CHaOH
Cr
COD
BOD
TOC
TSS
VSS
TKN
P04
S04
Cl
Oils
02 Uptake
Photomicro-
graphs
No. Project Cost
495 $ 16,500
i on
550
550
40
120
120
100
50
20
500 $ 19,300
360
620
335
215
80
50
60
60
60
160
20
-170-
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TABLE 28 (Cont)
COSTS OF COMPLETED TREATABILITY STUDIES
Study Wastewater Flow Study Length
Number Classification (MGD) Scope of Study (months)
3 Organic Chemicals <.5 1. General Wastewater Characterization 3
Production of 2,4-D 2. Biological Process Simulation
and 2,4,5-T a. Continuous Reactors (Act. Sludge)
b. Batch Reactors (Act. Sludge)
3. Stripping of Volatile Compounds
4. Warburg Evaluation
5. Oxygen Transfer Analyses
6. Sludge Settling Analyses
4 Organic Chemicals 0.5- 1. General Wastewater Characterization 5
1 0
2. Biological Process Simulation
a. Continuous Reactors (Act. Sludge)
b. Continuous Reactors (h'aste
Stabilization Ponds)
c. Batch Reactors (Act. Sludge)
3. Oxygen Transfer Analyses
4. Chemical Coagulation Analyses
5 Individual and Combined 25.0 1. General Wastewater Characterization 8
TreatabiUty Studies ? Blologlcal Process simulation
7 Chemical Plants and Continuous Reactors (Act. Sludge)
2 Refineries 3 Oxygen Transfer Analyses
Analytical Tabulation
Analysis
COD
BOD
ircc
V OD
TKN
02 Uptake
Warburg Anal.
Optical
Density
COD
BOD
TSS
VSS
Cl
Oils
Warburg Anal.
No
150
i in
i J\J
£C
D J
&c
O J
5
60
2
20
50
40
/ A
40
40
5
5
2
IR Spectrograph 2
COD
BOD
TSS
VSS
TKN
700
700
T A A
700
800
800
250
Project Cost
$ 4,900
Runs
$ 2,500
Runs
Samples
$ 58,000
-171-
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TABLE 28 (Cont)
COSTS OF COMPLETED TREATABILITY STUDIES
Study Wastewater Flow Study Length
Number Classification (MOD) Scope of Study (months)
5 4. Sludge Settling Analyses
(cont) 5. Chemical Coagulation Analyses
6. Neutralization Studies
6 Petrochemical <0.5 1. General Wastewater Characterization 4
Production 2_ QzQne Test Serles _ g Tes|. Runfj
3. Warburg Evaluation
4. Carbon Adsorption Simulation
(Batch Reactors)
7 Hydrocarbon <0.1 1. General Wastewater Characterization 3
2. Biological Process Simulation
a. Batch Reactors (Act. Sludge)
b. Batch Reactors (Aerated Lagoon)
c. Continuous Reactors (Waste
Stabilization Ponds)
Analytical Tabulation
Analysis
N02, N03
P04
Phenols
MBA
Alk/acidity
02 Uptake
COD
TOC
TSS
VSS
Warburg Anal.
Ozone Test
Nal Titrations
TOC
rnn
BOD
TSS
VSS
Cl
S04
P04
Alkalinity
°2
No. Project Cost
250
200
200
100
120
150
30 $ 3,500
60
10
10
2 Runs
8 Runs
30
150 $ 2,550
1A
15
15
10
40
1
1
1
6
* Costs Represent Actual Salary and Laboratory Costs Exclusive of Overhead - 1969 Cost Index
Overhead and profit ranges from 80 to 130 percent of these costs.
-172-
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mendations. Only a small portion of the wastewater survey is
included as a major portion of this effort is done in-house.
Often treatability studies are combined with the pre-
liminary engineering report which cover.s the design of one
or more process systems. Expenditures presented in Table 28
do not reflect the cost of a preliminary engineering report,
although it is customary to recommend specific unit processes
based on the treatability studies.
Data presented in Table 28 are representative of studies
performed on 5 petrochemical and 2 refinery wastewaters rang-
ing from less than 0.5 mgd to 25 mgd. Additional information
germane to the scope of each study such as study duration,
type and number of analyses, and general wastewater classi-
fication is included for detailed comparisons.
The most complex investigation was that of study number
5 which was concerned with the practicability of treating the
combined wastewaters from 7 chemical and 2 refining industries.
In contrast, study number 7 consisted of characterizing 2 waste
streams and conducting batch reactor treatability investigations.
-173-
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REFERENCES
1. Adams, C. and Eckenfelder, W. W., "Response of Activated Sludge
on Transient Loading." Center for Research in Water Resources,
Dept. No. 37, University of Texas at Austin, January (1969).
2. Agardy, F. J. and Kiado, M. L., "Effects of Refrigerated Storage
on the Characteristics of Waste." Proc. 21st Purdue, Indiana,
Waste Conference, pp. 226-233 (1966).
3. Albertson, Orris E. and Guidi, Eugene P., "Centrification of
Waste Sludges," Journal of the Water Pollution Federation,
Vol. 41, No. 4, April (1969).
4. American Petroleum Institute, "Manual on Disposal of Refinery
Wastes," Chem Wastes. Ill: 15-31 (1960).
5. American Petroleum Institute, Manual on Disposal of Refinery
Wastes, First Ed, New York (1969).
6. American Petroleum Institute, "Petroleum Industry Refinery
Water Reuse Survey," Completed by Crossley, S-D Surveys,
Inc., August (1968).
7. Anonymous, "Anti-Pollution Spending Near $1 Billion," The Qiland
Gas J. j>6:33-35, August 19 (1968).
8. Anonymous, Development of Operator Training Materials.
Prepared by: Environmental Science Services Corp. for
FWPCA. August 15 (1968).
9. ASTM, "Manual on Industrial Water and Industrial Waste Water,"
Committee D-19 on Industrial Water (American Society for
Testing and Materials Special), Technical Publication
No. 148-1 (1966).
10. Balakrishnan, S. and Eckenfelder, W. W., Unpublish Report (1968).
11. Earth, Edwin F., Brenner, Richard C. and Lewis, Ronald F.,
1'Chemical-Biological Control of Nitrogen and Phosphorus in
Wastewater Effluent," WPCF Journal, Vol. 40, No. 12,
December (1968).
12, Bayley, R. W., "Description of Wastewater Gases in Air,"
Effluent and Water Treatment Journal, (English) February-
March (1967).
-------
13. Beavon, D. K., Chute, A. E. and Lupfer, G. L. , Chemical Production
and Fuels Refineries (1969).
14. Bodien, Danworth G. and Stenburg, Robert L., "Microscreening
Effectively Polishes Activated Sludge Plant Effluent,"
Water and Waste Engineering, September (1966).
15. Boucher, P. L. and Evans, George R., "Microstrairiing - Description
of Application," Water and Sewage Works.
16. Boucher, P. L., "A New Measure of the Filterability of Fluids
with Application to Water Engineering," ICE Journal, Vol. 24:
No. 4, (1947).
17. Brunner, Carl A., "Pilot Plant Experiences in Demineralization
of Secondary Effluent Using Electrodialysis^" Journal of the
Water Pollution Control Federation, Vol. 39, No. 10, Part II,
October (1967).
18. Buzzell, J. C., Young, R. H. F. and Ryckman, D. W., Behavior of
Organic Chemicals in the Aquatic Environment, Part II,
Rept to the Manufacturing Chemist Association, April (1968).
19. Carnes, Billy A., "An Evaluation of Wastewater Sludge Drainability,"
Masters Thesis, University of Texas (1966).
20. Cecil, L. K., "Water Reuse and Disposal, Chemical Engineering,
pp. 92-104, May 5 (1969).
21. Chanin, G., et al, "A Safe Solvent for Oil and Grease Analysis,"
J WPCF. November (1967).
22. Clifford, D., "Total Oxygen Demand, "A New Instrumental Method,"
American Chemical Society, Midland, Michigan, November 4 (1967),
23. Copeland, B. J., Minter, K. W. and Dorris, T. C., "Chlorophyll
and Suspended Organic Matter in Oil Refinery Effluent Holding
Ponds," Limnology and Oceanography, 2:500-506 (1964).
24. Copeland, B. J. and Dorris, T. C., "Community Metabolism in
Eco-systems Receiving Oil Refinery Effluents," Limnology
and Oceanography, 2:431-447 (1964).
25. The Cost of Clean Water, III, Ind. Waste Profile No. 5 - Petroleum
Refining, U. S. Dept. of the Interior, FWPCA, November (1967).
-------
26. Davis, R. W., Biehl, J. A. and Smith, R. M., "Pollution Control
and Waste Treatment at an Inland Refinery," Proc. 19th Industrial
Waste Conference, pp. 126-138 (1964).
27. Delwiche, C. C., "Biological Transformations of Nitrogen Compounds,"
Ind. and Eng. Chem.. 48, 1421, September (1956).
28. "Design Standards for Wastewater Treatment Facilities," Texas
State Department of Health.
29. Eckenfelder, W. W., Jr. and Cardenas, P. R., Jr., "Scale-Up
from Laboratory Activated Sludge and Trickling Filter Units
to Prototype Design," Biotechnology and Bioengineering, VIII,
pp. 389-404 (1966).
30. Eckenfelder, W. W., Jr. and Ford, D. L., "Laboratory and Design
Procedures for Wastewater Treatment Processes," The University
of Texas Center for Research in Water Resources, Report: EHE-10-
6802, CRWR-31 (1968).
31. Eckenfelder, W. W. and Ford, D. L., Water Pollution Control -
Experimental Procedures for Process Design, Pemberton Press,
Austin, Texas (1970).
32. Eckenfelder, W. W. and O'Connor, D. J., Biological Waste Treatment
Pergamon Press, New York (1963).
33. Edde, H. J. and Eckenfelder, Jr., W. W., "Theoretical Concepts
of Gravity Sludge Thickening and Methods of Scale-up from
Laboratory Units to Prototype Design," Center for Research
in Water Resources, The University of Texas, p. 144 (1967).
34. "Electrodialysis in Advanced Waste Treatment," Water Pollution
Control Research Series, Advanced Waste Treatment Research,
U. S. Administration, Publication WP-20-AWTR-18 (1967).
35. Elkin, H. F. and Austin, R. J., Petroleum, Chapter 16, In
(C. F. Gurnham, Ed.): Industrial Wastewaters Control,
Academic Press (1965).
36. Engineering-Science, Inc./Texas, "Preliminary Design," Confidential
Report (1969).
37. Engineering-Science, Inc./Texas,, "Treatability Study of Nine
Combined Industries on Delaware," Confidential Report (1970).
-------
38. Engineering-Science, Inc./Texas, "Treatability Surveys,"
Compilation of confidential reports (1970).
39. Engineering^Science, Inc./Texas, Wastewater Survey - Confidential
Reports (1969).
40. Espino, E. and Gloyna, E. F., Sulfide Production in Waste
Stabilization Ponds, Center for Research in Water Resources,
The University of Texas at Austin (1967).
41. Forbes, M. C. and Witt, P. A., "Estimate Cost of Water Disposal,"
Hydrocarbon Processing and Petroleum Refiner, 44:158 (1965).
42, Ford, D. L. and Eckenfelder, W. W., Jr., "The Effect of Process
Variables on Sludge Floe Formation and Settling Characteristics,"
The University of Texas Center for Research in Water Resources,
Report 13, p. 149 (1966).
43. Ford, D. L., Eller, J. M. and Gloyna, E. F., "Analytical Parameters
of Petrochemical and Refinery Wastewaters," ACS Conference,
Houston, Texas, February (1970).
44. Foulds, J. M. and Lunsford, J., "An Analysis of the COD Method,"
Water and Sewage Works, March (1968).
45. Fox, David M. and Cleasby, John L., "Experimental Evaluation of
Sand Filtration Theory," Journal of the Sanitary Engineering
Division, Volume 92, SA-5, October (1966).
46. "FWPCA Methods for Chemical Analysis of Water and Wastes," U. S.
Department of the Interior, FWPCA, November (1969).
47. Gloyna, E. F. and Fisher, C. P., "Treatment of Activated Sludge
in Stabilization Ponds," Journal of j:he Water Pollution Control
Federation, Volume 37, No. 11, November (1965).
48. Gloyna, E. F., Ford, D. L. and Eller, J. M. , "Water Reuse in
Industry," Proc. 42nd WPCF Conference, Dallas, Texas,
October (1969).
49. Gloyna, E. F. and Ford, D. L.,"Injection of Wastewaters into
Disposal Wells," Center for Water Research and Water
Resources, University of Texas, Austin, Texas.
50. Gloyna, E. F. and Ford, D. L., "Petrochemicals and Waste Treatment,"
Presented at the 19th Canadian Chemical Engineering Conference,
Edmonton, Canada (1969).
-------
51. Goldstein, A. L., et al, "Total Oxygen Demand T A New Automatic
Instrumental Method for Measuring Ppllytion and Loading on
Oxidation Processes," American Chemical Society, Atlantic City,
New Jersey (1968).
52. Golf, D. L. and Gloyna, E. F., Technical Report #1 to the U. S.
Army Nuclear Defenses Laboratory, EHE-69-12, April (1969).
53. Hager, D. G. and Reilly, P. B., "Clarificafion-Adsorptipn in the
Treatment of Municipal and Industrial Wastewaters," Proc. 42nd
Annual Water Pollution Control Federation Conference, Dallas,
Texas (1969).
54. Harper, F. A., Operator Training by an In^Plant Apprenticeship
Program. J. Federal Water Pollution Control Federation 41,
pp. 2010-2017 (1969). ~~
55. Henrici, M. D. and Ordal, E. J., The Biology of Bacteria, Third
Edition, D. C. Heath and Co., Boston, Massachusettes.
56. Huber, L., "Disposal of Effluents from Petroleum Refineries and
Petrochemical Plants," Proc. 22nd Industrial Waste Conference,
pp. 1009-1024 (1967). ~""
57. Jennett, Charles J. and Santry, Jr., Israel W. , "Characteristics
of Sludge Drying," Journal of the Sanitary Engineering Division,
Volume 95, October (1969).
58. Jeris, John S., "A Rapid COD Test," Water and Wastes Engineering
(1967).
59. Jewell, W. J., "The Aerobic Decomposition of Algae and Nutrient
Regeneration," Ph.D. Dissertation, Stanford University (1968).
60. Kehrberger, G. and Barnhart, E. L., "Oil Assimilation in Biological
Systems," Proc. American Petroleum Institute, Division of Refinery
Houston, Texas (1970).
61. Koenig, L. and Ford, D. L., "Reuse Can Be Cheaper Than Disposed,"
Water Reuse, American Institute of Chemical Engineers, Chemical
Engineering Progress Symppsium Series 78, 63, 143 (1967T
62. Kwie, W. W., "Ozone Treats Wastewaters from Polymer Plant,"
Water and Sewage Works, February (1969).
63. Little, A. D., "Isolation and Identification of Persistent and
Problem Odors from Refinery Wastewater," API Annual Report
No. 6 (1967).
-------
64. Love, R. M. , "In-Plant Removal of Tertiary Butyl Alcohol," Texas
Water Pollution Control Association, Houston, Texas, July (1970.
65. McCarty, P. L., "Anaerobic Waste Treatment Fundamentals, Public
Works, September (1964).
66. McKinney, R. E. and Conway, R. A., "Chemical Oxygen in Biological
Waste Treatment," Sewage and Industrial Wastes, 29, 10, 1097-1106
(1957).
67. McPhee, W. T. and Smith, A. R., "From Refinery Wastes to Pure
Water," Proc. 16th Industrial Waste Conference, pp. 311-326
(1961).
68. Mancy, K. H. and Okun, D. A., The Effects of Surface Active
Agents on Aeration. Water Pollution Control Federation 37_,
pp. 212-227 (1965).
69. Manual on Disposal of Refinery Wastes, Methods for Sampling and
Analysis of Refinery Wastes, API (1969).
70. Manual on Disposal of Refinery Wastes, Volume on Liquid Waste,
Chapter 5, API (1969).
71. Manual on Disposal of Refinery Wastes, Volume on Liquid Waste,
Chapters 10 and 15, First Edition (1969).
72. Martin, J. M. et_al, "Ultraviolet Determination of Total Phenols,"
J WPCF, January (1967).
73. Nelson, 0. Fred, "Four Years of Microstraining at JCenosha, Wisconsin"
Waterworks Waste Engineering, July (1965).
74. Oeschner, W., Personal Communication, Berlin, West Germany (1969).
75. O'Farrell, T. P., Bishop, D. F. and Bennett, S. M., "Advanced
Waste Treatment at Washington, D. C." U. S. Department of the
Interior, Robert A. Taft Research Center, Cincinnati, Ohio,
May (1968).
76. Partridge, R. P. and Paulson, E. G., "Water: Its Economic Reuse
Via the Closed Cycle," Chemical Engineering, pp. 244-248,
October 9 (1967).
77. Paulson, E. G., "Adsorption as a Treatment of Refinery Effluent,"
Appendix to Report, CDRW Subcommittee on Chemical Wastes,
API Report No. C-623, July (1969).
78. Payn, D. S., "Routine Analysis of Phenols by Gas-Liquid
Chromatography;" Chemistry and Industry, (1960).
-------
79. Petrochemical Effluents Treatment Practices. Report 12020,
Federal Water Quality Administration, (Feb., 19.70).
80v Petroleum Industry Refinery Water Reuse Survey, American
Petroleum Institute, Submitted by Crossley, S-D Surveys,
Inc. (1968).
81* Porteous Ian K., "Mechanical Treatment of Sewage Sludge by
the Steam Injection Method," Municipal Engineer.
December (1968).
82. Quon, Jimmie E. and Johnson, Glenn N., "Drainage Characteris-
tics of Digested Sludge," Journal of the Sanitary
Engineering Division. Volume 92, April (1966).
83. Randall, Clifford W. and Koch, Thomas C., "Dewatering
Characteristics of Aerobically Digested Sludge,"
Journal of the Water Pollution Control Federation,
Volume 41, No. 5, Part II, May (1969).
84. Reddick, Tim, Control of Colloid Stability Through Zeta
Potential, Livingston Publishing Co., Wynewood,
Pennsylvania (1968).
85. Regional Water Quality Control Board, San Francisco Bay Region,
Resolution Numbers: 628, 776, 67-41, 67-31, 68-26, 68-27.
California (1965, 1966, 1967, 1968).
86. "Report on Air and Water Conservation Expenditures of the
Petroleum Industry in the United States," American
Petroleum Institute (1968).
87. Rhines, Chester E., "The Fundamental Principles of Sewage
Chlorination," Water and Sewage Works, March (1968).
88- Rice, W. W.and Co., Eckenfelder, W. W. and Associates and
Weston, R. F., Inc., "Projected Wastewater Treatment Costs
In the Organic Chemicals Industry," Unpublished Report to
the U. S. Department of the Interior, FWPCA (1969).
89. Rohwor, C., "Evaporation from Free Water Surfaces," U. S.
Department of Agriculture Tech. Bid 271, December (1931).
90. Rosengarten, G. M., "Union Carbide Corporation's Water
Pollution Control Program, 22nd Industrial Waste
Conference, pp 317-324 (1967).
91. Sawyer, C. N. and Bradney, L., "Rising of Activated Sludge in
Final Settling Tanks," gewage Works Journal, 17, 1191 (1945).
92. Schindler, H., "Chemical Treating Plant for Refinery Waste Water
from White Oils and Petroleum Sulfonates," Proceedings 6th
Industrial Wastes Conference, Purdue University, p. 304-312
(1951).
-------
93 . Schmauch, L. J. and Grubb, H. M,, "Determination of Phenols in
Wastewaters by Ultraviolet Absorption," Analytical Chemistry
(1954).
94 . Schroepfer, G. J. , j± al, Advances in Water Pollution Research,
Volume I, Pergamon Press Ltd., London (1964).
95 . Simard, R. G. , _e_t al, "Infrared Spectrophotometric Determination
of Oil and Phenols in Water," Analytical Chemistry (1951).
96 . Sosewitz, Ben and Hinsly, Thomas D., "Digested Sludge Disposal
on Crop Land," journal of the Water Pollution Control
Federation, Volume 41, No. 5, Part I, May (1969).
97 . Sparr, Anton E., "Sludge Handling," Journal of the Water Pollution
Control Federation, Volume 40, No, 8, Part I, August (1968).
98 . Standard Methods for the Examination of Water and Wastewater,
American Public Health Association, Inc., 12th, Edition (1965).
99 . Stanley, D. R., "Penetration of Floe into Sand Filters," Thesis,
Harvard University (1952).
100 "A Study of Sludge Handling and Disposal," Water Pollution
Control Research Series Publication, WP-20-4, U. S. Department
of the Interior, Federal Water Pollution Control Administra-
tion (1960).
101 . "Summary Report - Advanced Waste Treatment Research,"
Environmental Health Series, U. S. Department of Health,
Education and Welfare, AWTR-14, January (1962) - June (1964).
102 . Sun Oil Company, "Report of Predicted Wastewater Loadings for a
New Refinery in Puerto Rico," Confidential Report to
Engineering-Science, Inc./Texas (1969).
103 . Symons, J. M. and McKinney, R. W., "Biochemistry of Nitrogen in
Synthesis of Activated Sludge," Sewage and Industrial Wastes,
30, 7, 874, 890 (1958).
104, Taras, M. J. and Blum, K. A., "Determination of Emulsifying Oil
in Industrial Wastewater," Journal Water Pollution Control
Federation, November (1968).
105. "Ultimate Disposal for Advance Treatment Waste," Environmental
Health Series, Water Supply and Pollution Control, U. S.
Department of Health, Education and Welfare, AWTR-3.
106. U. S. Senate, Report of the Committee on Public Works to
Accompany S. 7. Report No. 91-351. 120 p. (1969).
107. Weber, A. P. "Residence-Time Spectrum in Continuous-Flow
Reactors," Chemical Engineering, p. 79-80, November (1969).
-------
108. Weston, R. P. and Hart, W. P., "The Water Pollution Abatement
Problems of the Petroleum Industry," Water and Sewage Works,
May (1941).
109. Wolf, Davis and Resnick, William, "Residence Time Distribution
in Real Systems," I & EC Fundamentals, 2, 287-293,
November (1963).
110. Wood, E., Perry, A.E., and Hitchcock, M., "A Critique on Total
Oxygen Demand Measurements," 159th ACS Meeting, Houston,
Texas, February (1970).
111. Wurhmann, K., "Nitrogen Removal in Sewage Treatment Processes,"
XVth International Congress of Terminology, Madison,
Wisconsin (1962).
112. Zanitsch, R.H. and Morand, J., "Tertiary Treatment of a Com-
bined Wastewater with Granular Activated Carbon."
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1
5
Accfxs ion Number
2
Subject Field & Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
Engineering-Science, Inc.
Title
"Preliminary Investigational Requirements - Petrochemical
and Refinery Waste Treatment Facilities"
10
Authors)
Engineering-
Science, Inc.
William Jewell, Ph.D.
Davis L. Ford, Ph.D.
16
Project Designation
EPA Project #12020 BID
21
Note
22
Citation
23
Descriptors (Starred First)
Wastewater Treatment*, Water Pollution Control*, Pollution Abatement*,
Pollutant Identification*, Industrial Wastes*, Water Quality Control*,
Sludge, Sewage Treatment, Biochemical Oxygen Demand, Chemical Oxygen
Demand, Heavy Metals, Lagoons, Organic Loading, Water Pollution
Treatment, Water Pollution Control.
25
identifiers (starred First) Wastewater Treatment Plant Preliminary Design*,
Wastewater Characterization*, Treatability*, Bench Scale Study, Pilot
Treatment Plant,
27
Abstract
This report compiles, interprets and describes the pertinent aspects of
conducting a preliminary wastewater treatability study for the refining
and petrochemical indis tries.
The characterization of wastewaters is the basis from which a treatability
study can be developed, and includes locating, analyzing, and interpreting
the nature of pollutional sources within a petrochemical or refinery complex.
The treatability study, whether it involves chemical, biological, or physical
treatment, must necessarily be programmed to yield definitive information
concerning pollutional removal rates, anticipated levels of residual or non-
removal rates, anticipated levels of residual or non-removable constituents,
and treatment process requirements.
The overall project of evaluating the treatability of a wastewater is predica-
ted on the assimilation of sufficient information from which the optimal
selection of treatment processes can be made. Given this objective, along with
manpower and cost constraints, any treatability'study must be carefully planned
and properly implemented. This report has 173 pages, 38 figures, 28 tables
Abstractor
and 112
Davis L. Ford
WR:102 (REV JULY 19691
WRSIC
SEND TO:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
US DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
SPO: 1989-359-339
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