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3. The organizational roles and responsibilities for operation
planning are not uniformly defined, making it necessary for
each operational planning effort to take account of the
particular mission (roles and responsibilities) of each
organization involved.
The initial relating of a planning program to overall plant development
will require that you:
1.1.1 Define the past history and expected future course of
events for the particular development.
1.1.2 Delineate the state of planning information from past
relevant development.
1.1.3 Identify major opportunities for operational planning
output from anticipated future development.
1.2 Delineate Special Circumstances and Contingencies
Operational planning activities and their related end-products do not always
unfold in optimum fashion. When operational planning does not follow along
the idealized model presented in Figure 3, an extra burden is imposed on one
or more of the potential beneficiaries of operational planning. That is,
the products which should serve as input to succeeding steps may not be
available, forcing earlier responsibilities upon the shoulders of those
involved with later stages of development. Three undesirable results which
may occur are:
1. District sanitary engineers and others responsible for the
procurement of wastewater treatment facilities and the opera-
tion of multiple plants may have to divert resources to the
preparation of manuals and other operational-support products.
Such diversion can delay schedules; result in unnecessary
inefficiency and error in translating research and development
-------
experience into operational implications; and involve waste-
fully redundant planning activity across a number of locales
in which the same processes, facility, or equipment may be
used.
2. Design, consulting, and architectural engineers may have to
spend excessive amounts of time seeking to obtain and derive
implications from raw data generated by the research and
development cycle.
3. Managers of individual treatment plants may be faced with
extended periods of less than optimum performance while seek-
ing to compensate for the lack of operational support informa-
tion which should have been available from the developmental
cycle.
The delineation of special circumstances and contingencies involves the
following four activities:
1.2.1 Define the most advanced stage of development (i.e., pilot_
plant, demonstration plant, etc.) applicable to each func-
tional component of the subject_ plant.
1.2.2 Compare the stage of development for the current effort
in each case with the most advanced precedential effort
in operational planning.
1.2.3 For each planning gap detected, determine the extent of
the additional burden imposed and the most practical means
for building it into the planning effort.
1.2.4 Incorporate the need for time and resources required by
special circumstances and contingencies into the overall
operational planning effort.
-------
1.3 Define Program Objectives
The definition of program objectives involves the identification of two
major kinds of "givens" that are imposed upon the operational planning
effort. First, there are the givens that are imposed on the output side of
the program—that is, the operational planning information and products to
be implemented and the level of plant performance to be achieved through
their implementation. Second, there are the givens imposed by the resources
and constraints of the operational planning program. The two classes of
givens must be identified and rationally synthesized to assure compatibil-
ity with the realities which influence the success or failure of resulting
program objectives. Some of the relationships among major elements involved
in defining program objectives are suggested in Figure 4.
1.3.1 Translate Required Outputs into Tentatiye_0bjectives
Estimates of output characteristics represent the principal set of output
specifications. As shown in the idealized model of Figure 3, the level of
specificity and expected accuracy increase with each successive stage of
development. The setting of objectives must take into account these
increasingly more stringent output requirements. The primary output char-
acteristics to be translated into planning program objectives are:
1. The physical form of the outputs.
2. The informational content of the outputs. (At early stages of
planning it will probably be possible to identify only classes
of information rather than any detail within a class.) Appen-
dixes A through D suggest classes of informational content
which will assist with delineation of the content character-
istics .
3. Dimensions of accuracy to which the outputs must adhere so
that desired reliability for the planning user is attained.
-------
Adjusted
and Refined
Program
Objectives
Translate Required
Outputs into
Tentative Objectives
Synthesize Resources,
Constraints and
Objectives
Define Resources
and Constraints
Planning
Information
from Other
Plants
Figure 4. Schematic Overview of Major Elements Involved with
the Definition of Program Objectives
10
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4. Descriptions of output comprehensiveness when the output
must completely describe a particular treatment parameter
or personnel activity.
5. Reaction time or lead-time relevant to the reporting of
planning information so that it will not lose its utility
as a plant product or as input to successive stages of
plant development.
1.3.2 Define Resources and Constraints
No program has unlimited resources of manpower, money, materials, facility.
or time. Each resource has some limit placed on it. Additionally, each
resource has organizational, technological, staff, policy, and administra-
tive limits. All available resources must be identified and the limits
which constrain them defined. All of the output requirements previously
identified must be weighed against the probability of achieving them with-
in the resources available to the program.
Some of the important resources and constraints to be considered, in addi-
tion to the obvious ones of time and money, are:
1. Previous treatment plants and processes. Planning informa-
tion from other plants is a particularly rich resource if
the plant of concern is sufficiently similar in all important
aspects. The degree of dissimilarity is an important con-
straint.
2. Developmental manpower. Some assumptions and estimates
must be made with respect to the knowledges and skills
required to develop operational plans, who will provide
them, and the level of effort required. A lack of person-
nel, or the money to purchase the services, is a significant
constraint.
11
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3. Management policy. Management policy or goals at the
national, state, and local level provide guidelines of
resources and constraints. Management policy can be
interpreted as either a sound measure of resources and
motivation or as a strong set of constraints or deter-
rents. In any case, most agencies operate under a com-
plex of specific regulations and fiscal budgeting which
must be recognized.
4. Special circumstances and contingencies. Special circum-
stances and contingencies affecting the development pro-
gram, as discussed earlier, can serve either as a significant
resource or as a constraint.
1.3.3 Synthesize Resources, Constraints, and Objectives
Resources and constraints may pose problems with respect to achieving what
were initially realistic program objectives, making necessary the adjust-
ment of program objectives. Any adjustments should adhere as closely as
possible to the original output requirements and objectives configuration.
1.4 Identify Priorities and Major Milestones
The achievement of program objectives is never a simple matter of defin-
ing what has to be done and then sitting back to wait for the desired
results to pour forth at the appointed time. Rather, there is generally
so much to be accomplished by the program that one must set priorities
on which objectives are to be attacked first and then be constantly alert
to the direction and speed of program progress so that the program can be
modified, as required, to attain its essential purposes.
Priorities assist with focusing in on those program activities which win
yield the most immediate and significant payoff. Milestones represent
12
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significant points along the program development path, serving to pace the
effort, provide a basis for assessment of progress, and as a framework for
the assignment or resources and responsibilities. The following five
steps will assist with the establishment of priorities and the identifica-
tion of major milestones.
1.4.1 Establish Priorities
There are not clear-cut differentials between the application of a plan-
ning approach to different treatment processes or treatment systems.
Where differentials do appear, however, it is with respect to the ultimate
payoff to be derived from the application of a planning approach to treat-
ment processes.
In general, the utility to be derived from effective operational planning
is a function of the degrees of freedom inherent to operations, mainte-
nance, and management of the individual treatment processes. The fewer
the degrees of freedom, the lower the potential for achieving increased
cost-effectiveness through operational planning. Additional factors are,
of course, the cost of the planning process and the impact of a treatment
process on effluent quality.
This really translates into priority differentials between treatment pro-
cesses according to the utility potential of operational planning. Some
treatment processes have a high potential for performance improvement while
others are so inflexible as to provide little potential for performance
improvement. Chlorination, for example, would obviously have less poten-
tial for performance improvement than would an activated sludge process.
It will be beneficial to set some priorities on which treatments or por-
tions of the plant configuration should be attacked first. The following
comments will assist in setting priorities:
1. Primary treatment processes are generally less amenable to
performance improvements than are secondary treatments,
13
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largely as a result of the comparatively few control param-
eters relating to process efficiency. Solids removal objec-
tives of primary treatment can generally be met with relative
ease because influent variability and other contingencies
have a less dramatic effect on primary outflow and costs
than would be the case with secondary or advanced treatment.
Control of processes is relatively straightforward, and the
level of skill and knowledge required for control is not as
great as with biological systems. The principal benefits
to be derived from operational planning are likely to be
in the form of reduced operations and maintenance costs
rather than significant improvements to primary effluent.
2. Secondary processes, due largely to their biological char-
acteristics, are rather complex and have many variables
impacting on process efficiency. While process control is
critical to effluent quality, there are large segments of
control technology which remain primarily a nondescript art
form rather than a systematic application of reproducible
and effective responses to given control situations. It is
felt that operational guidance and planning can achieve the
most significant improvements to cost-effectiveness through
secondary treatments (where less-than-optimum control can
have more of a degrading effect on effluent than would a
lack of control over the primary treatments which precede
it).
Maintenance aspects of secondary treatment processes also
deserve a high level of priority within operational plan-
ning. There is generally a much more diverse array of
equipment required for secondary treatments than for primary
treatments, requiring both maintenance specialists and/or
personnel with diverse technical skills.
14
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Advanced treatments are comparable to secondary treatments
in terms of the complexity of operational control and the
level of skill which must be developed for maintaining an
optimally efficient process. In terms of the possible
improvement to effluent quality, however, the range of
improvement between ineffective and optimally effective
operational control is small on a percentage basis for
most advanced treatments. Prom the standpoint of effluent
quality, it would be unwise to place too much emphasis on
operational planning for advanced treatments until optimal
control has been gained over primary and secondary treat-
ments. On the other hand, advanced treatments cannot be
neglected to the extent that a high risk situation occurs
with respect to damage to costly and sensitive equipment
or extreme operating costs.
Maintenance aspects of advanced treatments are estimated to
be comparable to the diverse requirements of secondary
treatments. That initial operational planning devoted to
maintenance should probably be limited to minimizing the
risk of equipment damage through faulty maintenance rather
than being concerned with more sophisticated elements of
the maintenance environment. Attention must, of course, be
turned back to advanced treatments when planning goals have
been reached for primary and secondary treatments.
Sludge handling and disposal is rather different from all
other treatments in that plant effluent is relatively inde-
pendent of sludge handling. Based on the premise that
operational planning should be geared to optimizing efflu-
ent quality at minimum cost, sludge handling and disposal
fall out of the picture. On a cost basis alone, however,
sludge handling and disposal can rank high in priority
15
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because of the high capital investment and operating costs
of some processes and the potential savings to be realized
through effective operational planning. A cursory examina-
tion of control parameters and total costs will generally
be sufficient to set priorities. The farmer who hauls away
sludge lies at one end of the scale and incineration lies
at the other end.
1.4.2 Identify Program Activities
Begin the identification of milestones by listing the major activities
required by the planning development program. An ''activity" is a unit of
program work, with the size of the unit depending on the needs of the par-
ticular program. Generally speaking, an activity will represent a sub-
objective and will culminate with the production of information or products
which serve as input to other, discernably different activities.
1.4.3 Order Activities
Determine the logical order for accomplishing each activity, paying par-
ticular attention to serial and parallel phasing of activities within the
total chain.
1.4.4 Estimate Time Requirements
Estimate the time requirements for each activity and otherwise apportion
time across activities so that their sum will result in objectives being
met on time.
1.4.5 Key Milestones to Critical Activities
Critical activities are characterized by their ability to halt or slow
down succeeding activities which are dependent upon them. Failure of an
activity to achieve an acceptable subobjective within an allotted time
frame will jeopardize program objectives unless some form of compensation
16
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is made. Critical activities, or combinations of activities, should be
considered milestones along the time dimension, with each milestone repre-
senting a point where certain activities, events, and products must be
accomplished.
1.5 Assign Responsibilities and Resources
Management of the operational planning program will invariably require the
assignment of responsibilities to personnel and the allocation of other
resources to ensure achievement of program objectives. Time, dollars, and
personnel will be the principal parameters of concern, each of which is
treated separately below.
1.5.1 Assign Personnel Responsibilities
The specification of program objectives, and the activities required for
meeting these objectives, will fairly well dictate what must be done. The
immediate problem to be faced is determining who, out of the available
pool of personnel resources, can best carry out required activities in
the operational planning program. The selection problem may, in fact,
also include problems related to the training and experience of personnel
in developing operational plans. The selection and training problems
may be distinguished from each other in part by the following:
1. Selection introduces into the program personnel who have
either:
a. Requisite skills or knowledge of operational
planning activities, or
b. Aptitude for required skills or knowledge.
2. Training issues are introduced through the need to create
requisite skills and knowledge within the personnel selected
for the planning development program. This Guide is intended
17
-------
to serve at least a part of the training and skill and knowl-
edge development required for the planning program.
In general, motivation of the development team members will be at least as
important a selection factor as technical skills in pollution control tech-
nology and operational planning. A firm belief in the improvements which
can accrue to the operational effectiveness of plants through proper plan-
ning, and a willingness to relentlessly pursue elements of planning, should
be a prime criterion for selecting members of the development team. The
assignment of specific activities should, of course, consider the best
possible matching of required skill and knowledge.
1.5.2 Allocate Time and Establish Schedules
There are many popular and useful techniques for scheduling the conduct of
a program (COST/PERT, etc.). It is important, however, to realize that
no scheduling system is infallible and that the monitoring and updating of
schedules will be necessary to prevent overexpenditures of resources and to
meet deadline commitments. One must also take cognizance of the fact that
the milestones previously identified form a hierarchy of milestones within
any schedule, some of which can be slipped without penalty and others
which cannot. Generally speaking, it is advisable to distinguish between
informal goals for your own use (which can be relaxed, if necessary) and
formally assigned goals, which are rigid.
Since it is known that design and development efforts tend to expand to
fill available time, avoid setting long-term deadlines in the allocation
of time and responsibilities without setting intermediate goals. Make
certain that program personnel understand intermediate goals and their
individual responsibilities for reaching them. Establish a formal schedule
for reaching each milestone and intermediate goal.
1.5.3 Allocate Money
Every program and project manager is faced with a shortage of money re-
sources to carry out the kind of effort he feels is necessary. Funds for
18
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operational planning are no exception. First, there will be the inevitable
struggle for operational planning funds versus hardware and process tech-
nology. Second, there is the difficulty of allocating funds among the
various elements of the planning program, which really translates into the
difficulty of putting money where it is most urgently needed without dis-
rupting a balanced program to meet all operational planning objectives.
There will often be a strong temptation to fund most heavily those activi-
ties where the state-of-the-art can be pushed even though the assigned
mission is to develop operational information and products to be applied
to specific treatment technology rather than to push the state-of-the-art.
Because the operational planning program does not depend heavily on hard-
ware or facility expenditures, money resources are expended almost exclu-
sively for salaries and overhead burden. This means that there is a
rather direct link between the time personnel spend in planning and
operational planning costs.
1.6 Establish Reporting and Monitoring Procedures
The program manager, as the principal channel for the exchange of informa-
tion between the planning program and key individuals, and as the person
responsible for reviewing and evaluating program status on a continuing
basis, must establish effective reporting and monitoring procedures.
Perhaps the most difficult aspects of establishing these procedures are
the timing, frequency, and form of review appropriate to the specific
program. On the one hand, the development team can be impeded by a mon-
itoring and reporting process that diverts time and attention from essen-
tial developmental activities. On the other hand, too little information
too late into the program fails to serve as a check on program status and
eliminates the opportunity to make any necessary midcourse corrections.
The establishment of reporting and monitoring procedures for operational
planning should involve the following four activities:
19
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1.6.1 Determine the key points for operational planning deci-
sions, the nature of decisions to be made at each point,
the alternatives available to the decision maker, and
the kinds of information required^ to make a rational
choice.
1.6.2 Determine who should be involved in making and imple-
menting decisions, what information each should have to
carry out his appropriate role.
1.6.3 Determine what legacy there might be from the information
implied by 1.6.1 and 1.6.2 for the preparation of opera-
tional support products such as job performance aids.
1.6.4 Select the most effective mode (e.g., written, verbal) ,
format, content, and timing for each report. Assign
responsibilities.
20
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2. DELINEATE PLANT PERFORMANCE CHARACTERISTICS
Plant performance characteristics here refer to those fixed and variable
parameters of a wastewater treatment plant which bear upon the costs and
quality of treatment. Since it is the general objective of operations,
as well as design, to achieve quality treatment at minimum cost, it is
essential that consideration of performance characteristics be a fundamental
aspect of operational planning. However, treatment plants differ markedly
in design, treat wastewater of different hydraulic and concentration load-
ings, and must meet effluent standards which may vary to a considerable
extent. No fixed set of performance data is available, nor can be expected
in the near future, which will suffice to guide the cost-effective manage-
ment, operations, and maintenance activities of individual plants. This
chapter describes how to:
1. Exploit and tailor available performance data.
2. Most effectively derive needed unique data and assumptions.
Figure 5 shows the five major steps in delineation of plant performance
characteristics. These steps are complex and highly interactive. Figure
6 illustrates a single-thread sequence of substeps which cuts across the
five major steps. The actual delineation of plant performance character-
istics and derivation of their operational planning implications will in-
volve a much more complex (simultaneous, contingent, and recurrent) deriva-
tion and use of data than are implied in Figure 6. However, Figure 6 sug-
gests the main sequence—a skeleton around which the full body of an
actual derivation of performance characteristic implications can be molded.
2.1 Define the Plant/Process Design Configuration
The performance of a treatment plant is largely dictated by the character-
istics of the individual equipment and facility components of the plant
21
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to
NJ
2.1 Define the
Plant/Process
Design
Configuration
2.2 Analyze
Contingency
Situations and
Functions
2.3 Analyze
Plant/Process
Control
Parameters
LJ.
2.4 Assign
Cost
Parameters
2.5 Identify
Plant/Process
Objectives and
xiteria
Basic
Operating
Objectives
and
Constraints
Figure 5. Major Steps in Delineation of Plant Performance Characteristics
-------
2.1 Define the
Plant/Process
Design
Configuration
2.1.1 Establish
the scope of
developmental
objectives
2.1.2 D<
process
and com]
i
2.1.3 Ii
conf igu]
impact c
1
= fine
stages
Donents
'
itegrate
rational
Jata
1
2.2 Analyze
Contingency
Situations and
Functions
2.2.1 Define
influent
characteristics
and associated
factors
2.2.2 Identify
external
contingencies
2.2.3 Identify
internal
contingencies
2.2.4 Integrate
contingency
impact data
2.3 Analyze
Plant/Process
Control
Parameters
2.3.1 Identify
influent/
effluent
relationships
2.3.2 Identify
control points
2.3.3 Integrate
functional
impact data
H
2.4 Assign
Cost
Parameters
2.4.1 Define
tradeoffs
2.4.2 Define
tradeoffs
2.5 Identify
Plant/Process
Objectives
and Criteria
2.5.1 Define
effluent
constraints
I
2.5.2 Define
effluent
variables , meas-
ures , standards
1 2.5.3 Define
3 output impli-
*| cations of
1 design features
I
2.5.4 Cc
date ba
objecti1
informa
f
snsoli-
sic
ng
-------
and the manner in which they are physically and functionally arranged to
form a treatment system. Knowledge of the physical plant is a prerequisite
to determining personnel requirements. Information about physical plant
and personnel jointly provide the principal basis for operational planning.
2.1.1 Establish the Scope of Developmental Objectives
Establishing the scope of developmental objectives within the context of
delineating plant performance characteristics, in a sense, involves simply
the use of analyses carried out under Step 1, Define and Manage the Opera-
tional Planning Program. However, this articulation between developmental
management and delineation of plant performance characteristics is essential
since appropriate delineation will be very importantly defined by the
developmental objectives toward which management is directed. More specif-
ically, developmental objectives are major determinants of the relative
importance to be placed on different elements and aspects of plant design,
the level of configuration analysis to be undertaken, and the approach to
be taken in deriving planning implications from configuration data. For
example:
1. Research, development, pilot plant operations, and full-scale
demonstrations may have implications across a spectrum of
specific plant configurations. Rather than focus upon the
implications of a discrete configuration for operational
planning, persons involved in research, development, pilot
plant operations, and full-scale demonstrations should em-
phasize :
a. Performance characteristics and operational impli-
cations which generalize across a range of configura-
tions, and the limits within which these limits are
applicable.
b. More specific analyses of performance characteristics
required as development moves from these advanced
stages toward specific plant design and construction.
24
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Manufacturers and vendors of wastewater treatment equipment
may have operational planning impacts across a spectrum
of specific plant configurations. As with research and
development, manufacturers and vendors should strive to
emphasize:
a. Performance characteristics and planning factors
applicable to a specific treatment plant situation,
the interactive effects with other treatment equip-
ment, and the special situations and contingencies
which may arise at a particular treatment plant
installation.
b. Performance characteristics and related operational
planning factors which will generalize across
a range of treatment equipment applications and
installations. For example, the performance char-
acteristics and operational implications of a par-
ticular chemical feeding unit will vary according
to the nature of the chemicals used, the treatment
to which chemical addition is applied, and the over-
all environment under which the unit must perform.
District sanitary engineers, and others responsible for the
procurement of facilities and equipment, must set their
developmental objectives in accord with the specific needs
of individual plants and also in accord with generalizable
aspects which can contribute to improvements across the
range of treatment plants within their jurisdiction.
Consultants, design engineers, and architects, who are heavily
involved with demonstration plants and the construction stages
of treatment plants, will find their developmental objectives
being confined rather closely to specific plant configurations.
However, their efforts in operational planning for a specific
25
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plant will be considerably stifled unless they are able
to capitalize on other efforts of a more generalizable
form.
5. Operating personnel will find primary interest in the
discrete configuration of their own plant. The relative
importance to be placed on different elements and aspects
of the plant design, and the level of configuration analy-
sis to be undertaken at the plant, will be a function of
the effectiveness of previous operational planning for the
plant and the availability of generalizable data and con-
cepts for the planning process. While generalizable impli-
cations for planning may emerge from the planning efforts
of operating personnel, developmental objectives will be
most often concentrated on the problems of the specific
plant configuration rather than on generalizable data and
concepts.
2.1.2 Define Process Stages and Components
Not all plant design and configuration characteristics are likely to bear
fruit in the operational planning effort. There are some stages and com-
ponents of treatment plants that are not worth pursuing in terms of ulti-
mate payoff. The general priorities set in Step 1.4 should have narrowed
the field somewhat. It is now desirable to focus-in a little closer on
the treatment components and operational needs of the plant to set more
specific planning objectives.
Don't hesitate to exercise judgment in deciding what part(s) of the plant
or system configuration is in greatest need of operational planning atten-
tion. Set your developmental objectives on those elements of the design
configuration where operational gains are most needed and where the prob-
able yield to performance improvement is maximized.
26
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Table 1 reflects a sample of treatment technology areas having known
impact on treatment but which lack adequate control procedures and practices.
While the table is by no means comprehensive, it will provide at least
some insight into the elements and characteristics of treatment where sig-
nificant operational gains can be made.
2.1.3 Integrate Configurational Impact Data
Integration of configurational impact data provides a skeletal framework
upon which other performance characteristics of the plant can be hung.
Thus, hardware and facility become the common denominator for operational
planning information and communicating information between stages of treat-
ment development.
For each relevant process stage and component there is some number of
physical dimensions and specifications essential to the planning effort.
The dimensions and specifications required are a function of developmental
objectives and the process stages and components deemed of primary impor-
tance to operational planning. Integration of data must take place across
all those plant and process components having some bearing on how the plant
will be managed, operated, and maintained, which reduces to integration
across some number of the following specificational elements:
1. Specification of the size and other dimensional values
related to the loading capabilities for each unit of equip-
ment having configurational impact.
2. Measures for determining that equipment and components are
operating as they were designed.
3. Conditions beyond equipment capabilities and which would
lead to equipment failure.
4. Measures of equipment criticality with respect to normal
treatment functioning (i.e., where equipment failure would
result in plant down time).
27
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Table 1
Sample Treatment Process Elements
Likely to Impact on Operational Planning
Treatment Process
Area of Technology Likely to Have
Impact on Operational Planning
Grit Removal
Pre-aeration
Prechlorination
Primary
Sedimentation
Automatic controls and instrumentation for varying
grit chamber utilization as a function of flow and
concentration loading (i.e., achieving some degree
of equalization).
Automatic controls and instrumentation for pre-
aeration as a function of plant loading.
Interactive effects of pre-aeration on other processes
(i.e., oil and grease skimmer, activated sludge, etc.)
Chlorine dosage rates and frequency of application
as a function of influent concentration parameters
and treatment situations (i.e., septic conditions
during hot weather, etc.).
Interactive effects of primary sedimentation on other
processes (flow velocity/retention time/overflow
rate versus digester efficiency, activated sludge
parameters, etc.).
Utilization of multiple tanks as a function of load-
ing.
Relationships between test results and control param-
eters (i.e., turbidity versus loading and retention
time, etc.).
Sludge characteristics as a function of loading and
scraper control parameters (i.e., length of time
operated and frequency of operation) .
Sludge characteristics versus pre-aeration of pre-
chlorination parameters.
Tank surging versus pumping rates and tank baffling.
Coagulant dosage rates as a function of loading
characteristics and the type of coagulant used.
Preparation, conditioning, and chemical feed tech-
niques versus primary and secondary treatment per-
formance characteristics (i.e., relative sludge
volumes and densities, etc.).
Process degradation as a function if improper prep-
aration, conditioning, or feeding of chemicals.
28
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Table 1 (Continued)
Treatment Process
Area of Technology Likely to Have
Impact on Operational Planning
Imhoff Tanks
Trickling Filter
Activated Sludge
Flow control versus concentration and treatment
performance.
Control parameters versus sludge viscosity and
foaming.
Influent loading and environmental factors (such
as ambient temperature) versus standards of per-
formance .
Influent pumping rates versus filter loading and
detention time in settling tanks.
Recirculation rates versus filter loading and
detention time in settling tanks.
Laboratory analyses versus control parameters
and optimal settings (such as recirculation rate)-
Observable symptoms of operational problems,
troubleshooting procedures, and corrective con-
trol actions.
Causes, cures, and preventive practices for such
problems as ponding, odors, filter flies, and
icing.
Standards of performance as a function of influ-
ent loading.
Relationships between laboratory tests, loading,
and control settings.
Observable symptoms of process malfunction versus
corrective control actions and preventive meas-
ures (i.e., sludge bulking, frothing, loss of
sludge activity, etc.).
Control procedures for air, oxygen, and combined
aeration systems as a function of loading and
process performance parameters.
Sludge return rates versus loading and performance
parameters.
Waste sludge parameters versus biomass character-
istics and loading parameters.
Sludge volume index and sludge age as a function
of loading and process control parameters.
29
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Table 1 (Continued)
Treatment Process
Area of Technology Likely to Have
Impact on Operational Planning
Activated Sludge
(Continued)
Intermittant Sand
Filters
Lime Clarification
Microscreening
Carbon Absorption
Sludge Digestion
Aeration control parameters versus mixed liquor
solids concentration.
Dosage rates and interval between doses of influ-
ent as a function of loading parameters and
filter condition.
Lime dosage rates versus operating pH and water
concentration characterististics .
Automatic controls and instrumentation for lime
feed as a function of pH and hydraulic loading.
Solids loading versus filter efficiency and back-
wash requirements.
Failure symptoms, corrective actions, and preven-
tive measures for known problem areas (i.e.,
manganese buildup on metal screens, oil and
grease clogging, slime clogging, etc.).
Control parameters as a function of hydraulic and
concentration loading (i.e., drum speed, backwash
pressure, bypass wire adjustment, screen blanking,
etc.).
Minimum contact time as a function of inflow
parameters and the design characteristics of the
particular carbon absorption system.
Carbon reactivation and makeup requirements as a
function of influent loading.
Interactive effects of primary and secondary
treatments on the carbon absorption process.
Automatic controls and instrumentation for the
process as a function of plant loading and efflu-
ent standards.
Near real-time tests and observable characteris-
tics of digested sludge as control input for
digester performance.
Digester temperature versus digestion time, sludge
characteristics, rate of sludge pumping, and
sludge/supernatant withdrawal rates.
30
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Table 1 (Continued)
Treatment Process
Area of Technology Likely to Have
Impact on Operational Planning
Sludge Digestion
(Continued)
Sludge Conditioning
Vacuum Filtration
and Centrifugation
Chlorination
pH, volatile acid content, and gas production
versus stages of digestion and digester perform-
ance .
Interactive effects of supernatant liquor with
primary and secondary treatment processes.
Interactive effects of digestion of vacuum fil-
tration or centrifugation.
Digested sludge feeding versus digester perform-
ance.
Near real-time test or observable sludge charac-
teristics indicative of sludge condition.
Chemical conditioner types and dosage rates as
a function of sludge condition.
Sludge conditioning parameters versus filter or
centrifuge efficiencies.
Solids content of sludge versus filter/centrifuge
efficiency.
Correlation of diurnal chlorine demand and auto-
matic control setpoints.
Dosage rates and points of application as a func-
tion of odor control problems.
Dosage rates and frequency of application as a
function of sludge volume index when used to
control sludge bulking in activated sludge pro-
cesses or as foam control in Imhoff Tanks.
Dosage rates and points of application for chlorine
as a means of offsetting the corrosive effects of
hydrogen sulfide.
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5. Failure symptoms and probable causes of failure for each
symptom.
6. Preventive maintenance recommendations and the interval
between tasks for each equipment component.
7. Projections of mean time between failures for each equip-
ment component.
8. Projection of mean time to correct equipment failures.
9. Estimates of preventive maintenance task time requirements.
10. Critical path flow diagrams to highlight serial and paral-
lel sewage flows and the probable effects of a failure
along each path.
2.2 Analyze Contingency Situations and Functions
Treatment plants are subject to a wide variety of contingency situations,
ranging from influent loadings which exceed the design specifications of
the plant to internal failures which can result in a loss of adequate
treatment. Of the nonstandard situations which can develop during the
lifetime of any treatment plant, some are totally unpredictable and impos-
sible to foresee while others occur frequently enough to be acknowledged
as distinct possibilities and plans made for dealing with them should they
occur.
Defining and analyzing contingency situations serves to provide a founda-
tion for the ultimate development of information to:
1. Alert plant personnel to sensitive situations which might
occur.
2. Identify the treatment functions which would be affected
by specific nonstandard situations and the nature of the
impact.
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3. Provide cues for the early detection of contingency situations.
4. Provide a plan of action for dealing with each contingency
situation and thus minimize loss of treatment, danger to per-
sonnel, and cost.
The development of operational planning products for dealing with contin-
gency situations will be dependent on the initial ability to:
1. Acknowledge situations to which treatments are susceptable.
2. Determine the probability of each contingency situation
occurring within the context of a specific plant.
3. Formulate rational plans for dealing with each contingency
situation.
4. Implement a contingency plan for each situation consistent
with the level of threat posed by nonresponsiveness.
The individual planning activities attended to during any given planning
effort will be governed by the stage of development for which the plan-
ning is being directed.
2.2.1 Define Influent Characteristics and
Associated Factors
Influent characteristics represent a special form of contingency situation
facing wastewater treatment plants; neither the hydraulic nor concentration
loading can be expected to be steady-state. Diurnal fluctuations, shock
loading by concentrated wastes, flooding, and other influent contingencies
pose a potential threat to treatment capabilities.
Some variation in influent is expected; indeed, it is this variation that
poses one of the essential needs for control over treatment processes.
However, variations in loading beyond the controllable design features of
treatment pose serious problems, possibly resulting in the loss of bio-
logical treatments and/or the discharge of an unacceptable effluent. In
33
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both cases, the characteristics of the influent represent essential infor-
mation for developing effective operational plans.
The influent loading information of greatest value concerns the extreme
situations which might occur rather than the average values to which this
information is so often reduced as part of initial design requirements for
a plant. Be rigorous in considering all influent parameters and pay par-
ticular attention to those parameters which, either individually or in
combination, could have a significant impact on the plant and its optimal
operation.
2.2.2 Identify External Contingencies^
There are a number of external contingencies to which plants are suscep-
tible and over which there is little direct control. Ambient temperature,
humidity, rain, snow, and power failures are but a few examples. Compen-
sation for the effects of these contingencies must be provided through the
design of the plant and, more importantly with respect to operational
planning, operational control of the plant.
Consider each external parameter of the plant environment with respect to
the influence each may have on the treatment plant generally and on efflu-
ent quality specifically. Pay particular attention to noting sensitive
parameters which could result in:
1. Danger to plant personnel.
2. Total or partial loss of treatment effectiveness.
3. Damage to treatment equipment or facility.
2.2.3 Identify Internal Contingencies
Within the confines of the treatment plant, there are many contingency
situations which can impact on treatment effectiveness and costs. Perhaps
the most easily recognized are those dealing with equipment and facility
failures; pumps become clogged, automatic controls get out of calibration,
34
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instruments refuse to function properly, motors fail, and so forth. This
general class of contingencies has to do with equipment reliability and the
impact on treatment brought about by equipment failures. The other prin-
cipal class of internal contingency situation has to do with operational
control over the plant by its human operators who, like every human, are
not infallible; sludge return rates get set too high or too low, settling
tanks short circuit, sludge bulking occurs, and so forth. This class of
contingency situations has to do with incorrect control of treatment pro-
cesses but is heavily interactive with influent characteristics, external
contingencies, and equipment malfunctions.
The identification and impact assessment for equipment and facility con-
tingencies is relatively straightforward if one assumes that every unit of
equipment is subject to failure and then, assuming that failure has oc-
curred, assesses the impact of that failure on treatment. Estimates of
equipment reliability (such as mean time between failure) will help in
tempering what is or is not an important internal equipment contingency.
Equipment manufacturers may have reliability information for their products
or might be requested to prepare such information. Lacking valid relia-
bility information, one is forced to make educated judgments.
Identification of control contingencies is best handled through an examina-
tion of the plant and process control parameters, a subject dealt with in
Substep 2.3, Analyze Plant/Process Control Parameters. Here, however- it
should be at least noted that each and every control parameter has some
optimal set point based on the design of the treatment equipment and the
influent and other characteristics at a given point in time. Control set-
tings or actions on either side of the optimal represent control contingen-
cies that, depending on the degree of divergence, will have a significant
impact on the treatment plant.
2.2.4 Integrate Contingency Impact Data
As is probably obvious, each class of contingency situation (i.e., influ-
ent, internal, etc.) not only has independent impact on treatment but they
35
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might also interact with each other in such a way as to multiply impact
significantly. By the same token, there might be some interactions which
would tend to nullify each other. Integration of impact data should serve
to:
1. Assess the interactive effects of all contingency situa-
tions and summarize their impact (or performance charac-
teristics) on the total of the plant.
2. Provide a consolidated pool of contingency information which
will serve as a check on the adequacy of the plant and
process design configuration.
3. Provide a basis for ensuring that all control parameters and
procedures for contingency situations are fully considered
as part of operational plans.
Integration of data may be simplified in some cases through development
of decision tables which embody contingency situations along one dimen-
sion and appropriate impact conditions and related control actions along
another dimension.
2.3 Ana 1 yze_P 1 _ant/Process .C_o^roT_P^ameters_
Treatment plants, regardless of how rudimentary they may be, will have at
least some capability to adjust treatment parameters and thus compensate
for variations in loading and other factors bearing on treatment effec-
tiveness. The modern treatment plant involves a large number of control-
lable parameters, some of which are controlled through automatic devices
and instrumentation and others which must depend on human sensing and
manipulation for proper control.
The design objectives of treatment plants are based on the assumption that
optimal control is exercised over the controllable features of the plant.
Yet, if these objectives are to be met, there must be some method for
36
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identifying appropriate control responses and defining the method for
executing control. There are three essential control characteristics which
will assist with identifying and defining control parameters. They are
characterized by the following:
1. The source of input data. What is the source of input
information for making a dontrol adjustment? Is information
acquired through human senses or through automatic indica-
ting and recording devices?
2. The mode of control utilized. Is control adjustment manu-
ally or automatically carried out?
3. The decision-making process. What is the method or proce-
dure for comparing sensed data against standards to detect
a need for control change, the direction of required control
action, and the magnitude of control change to be made?
A relatively standard method of describing this basic information about
the control process is through the use of control loops. In brief, a con-
trol loop defines how a control function is executed. There are at least
three alternative forms of control loops, ranging from those of completely
manual control to those of totally automatic control. There must be at
least one control loop specified for each control function of the plant,
with a control function being defined as the requirement to modify some
variable of treatment to accommodate a change in influent loading, internal
contingencies, or external contingencies bearing on treatment performance.
Figures 7 through 9 illustrate the control loop concept for some typical
combinations of manual and automatic control.
Control loops are central to the entire effort directed to operations
aspects of treatment plants. What the operator must do, how he knows when
to do it, and how he knows when it has been done correctly are all impor-
tant elements of the control loop definition.
37
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Influent
Process
Controls
Treatment
Process
Effluent
Automatic
Control
Device
Manual Setpoint
Adjustment
Figure 7. Automatic Control with Manual Setpoint Adjustment
Influent
Process
Controls
]P»
Treatment
Process
Effluent
Direct
Manual
Control
Direct
Observation by
Human Senses
Mental Comparisons
Figure 8. Manual Process Control
38
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Influent
Process
Controls
V
\
\
Direct \
\
Manual
Control
^
\
\A. _^
Treatment
Process
/^
---£ /
dt -" " \^
Effluent
1 /
X
^[AAjy
Measurement and
Recording Instruments
Figure 9.
Mental Comparisons
Sensing and Recording Instruments
with Direct Manual Control
2.3.1 Identify Influent/Effluent Relationships
Influent and effluent relationships provide a major source of input and
feedback data to the control of a plant. A large percentage of the con-
trol parameters for a plant are a function of these relationships; for a
given influent loading to a specified design configuration, the effluent
quality should be predictable. If the effluent quality achieved by the
plant does not reach expectations for a given value of loading, then there
is reason to believe that something is amiss with operation of the plant.
The influent and effluent relationships of principal concern to the opera-
tor, however, are those which serve to trigger the need for control activ-
ities , provide guidance on the direction and magnitude of required control
change, and provide positive and timely feedback on the adequacy of the
control activities carried out.
Not all influent and effluent relationships will impact on plant or pro-
cess control. Attention should be concentrated on those relationships
which do impact on control of the plant. At least one means for identify-
ing relevant relationships is to establish a range of influent loadings
39
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(guided by influent contingency information) and test each of these values
against the design configuration to determine if a control change is dic-
tated by the change from one value to another.
The results of this effort should be an enumeration of those relationships
which will define control loops in terms of influent (as sensed information
for making a control change) and effluent (as both the cuing information
for control and as feedback on the results of control change).
2.3.2 Identify Functions and Control Points
Influent and effluent relationships will not account for all control param-
eters of the plant, and so a functional approach becomes appropriate to
ensure that all parameters will be included in the planning effort. Con-
trol functions and control points provide meaningful information without
requiring detailed levels of specification on how (i.e., automatically,
manually, etc.) the control will ultimately be carried out in the plant,
thus leaving a degree of flexibility in the design process without hamper-
ing either the plant design effort or the planning effort. The important
issue at this time is to determine what control is necessary.
Identification of functions and control points can be effectively accom-
plished through either one or both of the following approaches :
1. Identify controllable features of unit treatments and other
equipment components through examination of those detailed
hardware specifications which are available. For each con-
trollable feature included in the plant design (such as
varying blower speed or the number of blowers utilized in
the aeration of activated sludge), there is a control loop
to be identified. If there is a control feature, then there
must be some control function to be satisfied by that feature.
Detailed plant design requirements or manufacturer's specifi-
cations will generally set forth all such control features.
40
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2. Identify the functional control requirements of the plant
or process to change with respect to influent loading,
internal, or external contingencies. While this approach
will not permit the level of specificity possible through
an analysis of hardware, it is well suited to early stages
of plant and process design (where hardware details are
unavailable) and as an overall check on the capabilities
of hardware to satisfy all control requirements.
Functional control data will require "fleshing out" in terms of sensing,
comparative, and control mode information as it becomes solidified through
the process of detailed plant design. These factors will be considered
as part of Step 2.5, Identify Plant/Process Objectives and Criteria. Addi-
tionally, functional control requirements serve as primary input to the
definition of man-machine tradeoffs, covered in Step 2.4, Assign Cost
Parameters.
2.,3,.3 Integrate Functional Impact Data
The integration of functional impact data directs itself to the overall
assessment and further analysis of operational control as it impacts on
treatment plants and processes. All elements of the control environment
should be considered together at this time so that interactive effects,
as well as individual effects, become embodied into planning for opera-
tional aspects of treatment. The end result of this effort should be a
more comprehensive understanding and definition of:
1. The criticality of each control parameter in terms of its
impact on plant effectiveness, costs of treatment, danger
to personnel, and damage to plant equipment and facility.
2. Relationships between control status, influent/effluent
status, internal contingencies, external contingencies,
and desired operational performance of the plant.
3. Thresholds for determining that sensed data is "in" or "out11
of tolerance.
41
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4. How control functions will be carried out (i.e., manually.
automatically, or a combination thereof).
5. Support information applicable to control parameters and
alternate modes of control.
2.4 Assign Cost Parameters
A primary objective of wastewater treatment plants is to achieve highly
cost-effective treatment, an objective that cannot be reached without
knowledge of cost factors and how these factors relate to treatment effec-
tiveness. Although there is an almost infinite variety of cost parameters
of potential use in operational planning, the breakdown of parameters and
variables shown in Table 2 provides at least the obviously required data
for planning and decision-making purposes.
With the exception of capital costs, which can be expected to remain rela-
tively fixed once a plant is constructed, costs are largely dependent on
influent loading, the level of effluent quality strived for by the plant,
and the operational control and maintenance philosophy adopted. If a
viable cost-effectiveness ratio is to be established for a plant, or if
the minimum cost is to be achieved for given levels of treatment, it is
imperative that all variables related to treatment performance be identi-
fied and defined in terms of whatever "sensitive" relationships exist.
As a general rule, one will gain maximum utility from cost information as
a tool only through a breakdown of costs which go at least to the unit
treatment level or, preferably, to the major components of each treatment
and plant appurtenance. A cost accounting should always be employed
rather than a general accounting so that the elements entering into the
cost of treatment can be analyzed and applied on a unit basis (where plant
management, operations, and maintenance staffs will have an opportunity
to exercise cost controls).
42
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Table 2
Breakdown of Cost Parameters and Variables
Parameter
Variables
Capital Cost
Design and construction costs plus
interest on monies borrowed. This
total cost is generally amortized
over the expected life of the
facility or equipment.
Labor Cost
Management personnel
Administrative personnel
Operator personnel
Maintenance personnel
Technical support personnel
Clerical personnel
Etc.
Cost of Consumables (treatment)
Coagulants
Chlorine
Lime
Ferric chloride
Etc.
Power Costs
Electricity
Natural gas
Other power costs
Maintenance Supplies
Replacement parts
Lubricants
Packing and other consumables
Paint
Pipe
Replacement tools
Etc.
Service Costs (nonplant personnel)
Consultants, design engineers,
Laboratory analysis
Maintenance
Data processing
Customer billing
Etc.
etc.
General
Water and other utilities for
the plant
Office supplies
Insurance, etc.
Legal costs
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2.4.1 Define Man-Machine Tradeoffs
One of the most significant degrees of freedom in the design of treatment
plants and the related costs of treatment has to do with the tradeoffs
which can be made between people and equipment to perform plant functions.
With respect to the preceding substep dealing with control parameters, for
example, certain functions can be performed either through the use of
personnel or through the installation of automatic control devices. The
final decision for the plant configuration must certainly take into con-
sideration the costs for each of the alternative control modes. Man versus
machine decisions based solely on engineering state-of-the-art or capital
investment costs will surely lead to an unhappy compromise.
Identify all of those plant functions which legitimately have alternatives
for accomplishment. Be realistic though. Refrain, for example from
stretching the technological state-of-the-art to include instrumentation
and controls which are insufficiently developed for the specific treatment
application. By the same token, do not arbitrarily exclude available
instrumentation and controls simply because they have never been applied
to a treatment situation before.
For each function having man-machine alternatives, define those character-
istics of each alternative which will bear on the decision to choose one
over the other. Perhaps the best way to do this is to consider, first of
all, the treatment performance advantage or decrement attributable to each
of the alternatives. Then, consider other factors bearing on the trade-
off decision and which, ultimately, will affect treatment costs. Some of
the factors to be considered for each alternative include:
1- Capital costs. The initial cost of equipment, especially
sophisticated control equipment, might easily outweigh the
additional skilled manpower required by a largely manual
control function.
44
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2. Labor costs. While designs favoring automation might sub-
stantially reduce operations costs, increased maintenance
labor costs might more than compensate for the savings.
3. Availability of skilled labor. The availability of skilled
operators versus the availability of skilled maintenance
personnel in the local labor market for a treatment plant
is an important tradeoff consideration.
4. Skill diversity. The degree of special skills required
for operating or maintaining treatment control can diverge
radically. Part of the tradeoff decision pertains to
limiting the number of special skills required. Otherwise,
design might dictate need for electronic technicians,
pneumatic technicians, hydraulic technicians, and so forth,
when some degree of standardization might result in the
need for only one skill area.
2.4.2 Define Criteria/Cost Tradeoff
Each of the tradeoff considerations which apply to man-machine decisions
will have some point along a continuum where it becomes advantageous to
either accept it or reject it in favor of another alternative. Cost-to-
performance effectiveness ratios are obviously the single/ most important
criteria for structuring the configuration of a treatment plant, yet it is
quite difficult to quantify the performance dimension of treatment and
link it to treatment cost.
In spite of the need to induce a certain element of nonscientific judgment
into the assessment of cost-effectiveness, a conscientious effort will
generally produce information of sufficient validity to more than offset
the risk inherent to the procedure. In the majority of cases, there will
be some specified level of effluent quality which must be achieved by the
plant; the issue thus becomes one of determining the cost of the alterna-
tives capable of producing that quality, subject to contingency situations
45
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and functions. In other cases, there will be a desire to exceed prescribed
standards; the issue reduces to quantifying the marginal treatment effec-
tiveness which can be realized by incremental changes in the cost of
treatment. In both instances, one should strive to correlate cost and
treatment variables which will help to answer such questions as;
1. To what extent do dependent and independent variables of the
specific treatment configuration account for variations in
treatment costs?
2. What conceptual relationships exist to provide a realistic
model for predicting the positive or negative cost incre-
ment when either the level of treatment or the alternative
control procedures for the plant/process are changed?
3. What mathematical relationships exist between cost and
treatment effectiveness and how can these relationships
be exploited for gaining optimal control over individual
processes and the plant as a whole?
4. What are the cost-sensitive factors for a given function
and at what point of loading or level of treatment does it
become advantageous to turn to some other alternative?
2.5 Identify Plant/Performance Objectives and Criteria
There are, invariably, standards placed on the quality of treated waste-
waters discharged to the nation's water basins. The standards imposed by
Federal, state, and local government represent the minimum level of treat-
ment to be achieved by a plant; hence, they represent a minimal level of
treatment objective. Plant performance objectives at a higher level of
treatment may be set by the local plant authority out of a concern with
the nation's natural resources and environmental problems.
46
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2.5.1 Define Effluent Constraints
The requirements imposed on effluent discharges significantly constrain
both the design of treatment plants and all operational characteristics
which bear on effluent quality. For example, bypassing raw sewage during
periods of high hydraulic loading, once a common practice, has been con-
strained in recent years by legislative requirements placed on discharges.
Holding tanks, separation of storm and sewage waters, and other facets of
plant design are constrained by effluent requirements as are operational
control procedures and practices of the plant.
Identify and define those constraints imposed on the design and operation
of the plant by effluent requirements. First, define the nature of require-
ments and standards placed on discharges by governmental agencies at the
location of the plant. As appropriate, increase the stringency of require-
ments according to whatever other goals and desires may apply. Then,
compare and test these objectives against the design configuration of the
plant to ascertain those features of the design configuration which will
be sensitive to maintaining objective levels of effluent quality at all
times.
Sensitive design and operation features represent constraining factors
with respect to meeting or surpassing effluent objectives. The size of
sedimentation tanks is, for example, a sensitive design feature when hy-
draulic loading reaches that point where reduced retention time prohibits
meeting effluent objectives. Thus, to ensure meeting or surpassing efflu-
ent objectives, each sensitive feature should be incorporated into a
checklist for the design and development process and a thorough assessment
made of the impact brought to bear by:
1. Influent characteristics and contingencies.
2. Internal plant characteristics and contingencies.
3. External plant characteristics and contingencies.
4. Plant and process control functions and control points.
5. Man-machine tradeoffs.
47
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6. Resources for design and construction and cost-
effectiveness tradeoffs.
2.5.2 Define Effluent Variables, Standards, and Measures
Effluent quality must be expressed in quantitative terms which will posi-
tively define effluent objectives. Variables represent the elements of
the discharge measurable for quality; standards represent the specific
value to be achieved for each variable in order to meet treatment objec-
tives; and measures define the specific technique(s) to be employed in
assessing the achievement of standards for each variable. The purposes of
these more specific elements of effluent quality are twofold:
1. To delineate more specifically the constraints imposed on
design and development.
2. To provide a normative basis for evaluation and control
of the plant.
With perhaps a few exceptions, effluent quality will vary as a function
of the hydraulic and concentration loading of the influent to a plant.
Effluent objectives are thus set for the design of the plant according to
some value of estimated loading for the population to be served by the
plant. While effluent objectives are an important parcel of informa-
tion, the loading values on which objectives are based do not very often
coincide with the actual loadings experienced by the plant (particularly
during the early years of a plant's life). Moreover, objectives are
normally stated in such a way as to imply steady-state conditions while
plants actually operate under conditions that are quite dynamic.
Effluent criteria provide more meaningful measures of plant capability by
defining effluent quality in conjunction with loading conditions more
representative of the dynamics to which the plant will be subjected dur-
ing its life. Adequate definition of effluent criteria will require
multidimensional testing of at least the following against the design
configuration of the plant:
48
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1. Influent characteristics, both hydraulic and concentration,
representative of anticipated loading as it passes from the
"best case" to the "worst case" situation.
2. External contingencies bearing upon treatment effectiveness.
The results of this effort should be a series of criterion values to ex-
press the optimal performance expectations of the plant with respect to
contingency situations and functions, plant and process control parameters,
and cost parameters. In addition to criterion values, it is important to
express:
1. Time lag and other factors associated with diurnal loading
fluctuations and effluent criteria.
2. Critical influent loadings to which the plant is either
sensitive or vulnerable.
3. The range of influent and other variables impacting on
treatment, and selected values within the range, to provide
a useful model for plant control functions.
4. Internal and external contingency situations to which efflu-
ent criteria are sensitive.
An initial starting point in the identification of criterion values is to
make a list of the parameters which are likely to vary over the life of
the plant. A select set of variables for each parameter is then tested
against the design configuration. The following list is representative
of some relevant parameters and variables.
1. Hydraulic loading.
a. Average daily flow.
b. Maximum flow rate within a day.
c. Minimum flow rate within a day.
d. Average hourly flow.
e. Population equivalent for area served by the plant.
f. Etc.
49
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Concentration loading.
a. BOD.
b. pH.
C. COD
d. Suspended solids.
e. Dissolved solids.
f. Organic solids.
g. Settleable solids.
h. Colloidal suspended solids.
i. Total solids.
j. Volatile liquids.
k. Dissolved gases.
1. Pathogenic bacteria.
m. Saprophytic bacteria.
n. Aerobic bacteria.
o. Faculative aerobic bacteria.
p. Faculative anaerobic bacteria.
q. Macroscopic organisms.
r. Nitrogen.
s. Phosphorus.
t. Insecticides.
u. Heavy metals.
External contingencies.
a. Influent temperature.
b. Ambient temperature.
c. Street washings and storm flows.
d. Ground water infiltration.
e. Toxic industrial spills to sanitary sewer.
f. Etc.
50
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.2.5.3 Define Output Implications of Design Features
Insofar as plant operator personnel are concerned, effluent variables,
standards, and measures come most importantly into play with respect to
the individual unit treatments which comprise the plant. Individual and
serial or parallel combinations of unit treatments must each contribute
some functional role in the achievement of effluent criteria. Thus, each
design feature of the plant has some implication(s) for reaching effluent
criteria and should have its own set of outflow specifications, derived
from effluent criteria and the plant design configuration, to serve oper-
ating needs.
Using plant effluent criteria as independent variables, it becomes possible
to derive outflow criteria for unit treatments under the conditions speci-
fied for each plant criterion value. The unit treatment outflow criterion
values thus derived characterize the effectiveness which must be achieved
by each unit treatment if plant effluent criteria are to be met.
Because of the dynamics upon which both effluent and process outflow cri-
teria are based, the achievement of criteria will cause important design
and control implications to emerge- By alternatively analyzing different
contingency situations and functions, plant and process control param-
eters, and cost parameters with respect to criterion values, output impli-
cations of the following types can be noted as input to a host of opera-
tional planning activities.
1. Outflow variables and criterion values for each unit
treatment.
2. Effects of influent and contingency variables upon the
function performed by treatment processes.
3. Influent, effluent, or other control data requirements.
4. Methods for sensing or measuring control data requirements.
5. Thresholds for determining that sensed information is "in"
or "out" of tolerance.
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6. Relationships between control status, influent/effluent
status, and threshold values in determining appropriate
control actions.
7. Effectiveness of alternative control modes (i.e., automatic,
manual, etc.) in keeping pace with the synamics of the plant
environment.
8. Required setpoint adjustments for automatic controls and the
basis for making each adjustment.
9. Manual control loops applicable to situations where it becomes
necessary to override an automatic control.
10. Support information for achieving and maintaining criterion
levels of performance through operational control.
11. Variable costs associated with reaching criterion performance
in view of contingency situations, alternative control modes,
and design feature tradeoffs.
2.5.4 Consolidate Basic Operating^ Objectives Informat_ij_n
The objectives and criteria for the plant and its processes are inevitably
subjected to some shifting during the design and development process as
design features and resources and constraints are weighed against each
other. Just as the design configuration of a plant must finally come to
a point of solidification, the objectives and criteria must also come to
a point of stabilization prior to the day when construction makes design
irrevocable.
When some degree of stabilization has occurred it is time to consolidate
all basic operational objectives and criteria into a compact and useful
definition of plant performance characteristics. The consolidated per-
formance characteristics of the plant serve as the final guide and specifi-
cations for operational planning materials development. To gain maximum
utility the consolidation process should:
52
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Weed out those alternative performance characteristics
which do not apply to the final design configuration.
Identify and correct errors which may be present in design
or operational information.
Ensure completeness in the delineation of all performance
characteristics.
Integrate performance characteristics into meaningful
information clusters as input to plan''- management, opera-
tions, and maintenance planning activities.
53
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3. DEFINE TASK AND JOB REQUIREMENTS
This chapter describes activities directed toward the identification of
personnel requirements for municipal wastewater treatment plants. These
activities are organized around the following five basic steps, each of
which results in products as defined briefly below:
3.1 Describe personnel functions results in a delineation of
the activities to be performed by personnel in relation
to and contrasted with functions to be carried out by the
physical plant. Such delineation is made, implicitly or
explicitly, early in the design of a process, equipment,
or facility. The rigorous recording and communication
of decisions about the allocation of personnel functions
not only provides the basis for more refined definition
of personnel requirements, it also can provide valuable
orientation materials for personnel concerning operation
and maintenance of the plant.
3.2 Describe tasks translates general personnel functions into
a detailed definition of worker activities and skills re-
quired to accomplish these activities. Preliminary estimates
of task requirements can be made early in the development
process—as soon as an allocation of functional responsibil-
ity is made between equipment and personnel. Skeletal task
identification must be rounded out and corrected as further
information becomes available from the ongoing development.
Task information is central to much of operational planning.
It is basic to position, job, and staff development. It
provides a rationale for personnel selection and classifi-
cation, wage and salary administration, training, and the
design of job-oriented manuals and other job aids. Task
54
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information also can help to focus on the important human
engineering design features required in a wastewater treat-
ment environment.
3.3 Describe positions defines the clusters of tasks which
should be carried out by a single individual. It provides
an efficient, but flexible, basis for operational manage-
ment to use in making job assignments and work schedules.
Positions can be defined as soon as task information
becomes relatively definite and stable.
3.4 Describe jobs defines the clustering of positions into the
jobs that will make up actual staffing for a plant. Although
much can be accomplished toward defining job requirements as
part of early design and development, the final determination
of job boundaries will be made by operational management.
3.5 Describe staffing quantifies task and job requirements in
terms of numbers of workers who should be employed in each
job. During design and development, it is possible to com-
bine general staffing criteria with functional and task in-
formation in order to establish relatively precise criteria
for staffing a given plant. Ultimately, of course, opera-
tional management must verify or modify such criteria for
staffing their plants.
3.1 Describe Personnel Functions
Effective wastewater treatment plant functioning requires a variety of
supporting functions on the part of personnel. Delineation of personnel
functions is a basic step in defining the operational planning problem.
It includes the following three principal substeps:
55
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3.1.1 Identify plant information.
3.1.2 Organize plant information.
3.1.3 Derive personnel functions.
3.1.1 Identify Plant Information
The informational products resulting from the Delineation of Plant
formance Characteristics (Chapter 2) should fulfill all essential informa-
tion needs about the specific plant. However, additional or supplementary
information may be found through any of the following sources:
1. Documentation for other similar plants can suggest functions
which have not yet been formally delineated for a new plant
in its early planning stages.
2. Policy, planning, and legal documentation relating to waste-
water treatment requirements for the community to be served
by the plant may help to clarify functional imperatives for
the plant.
3. Objectives, criteria, and control parameter (per Chapter 2)
descriptions as they may be presented in procurement and
design documentation.
4. Research, development, pilot plant, and full-scale demonstra-
tion reports relating to processes and components intended
for incorporation in the plant of concern.
5. Equipment specifications and descriptions for intended com-
ponents of the plant of concern. Such specifications and
descriptions may define:
a. Techniques and procedures for operating equipment.
b. Measures for determining whether equipment is opera-
ting according to design standards.
c. Failure symptoms and likely causes of failure.
56
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d. Preventive and corrective maintenance recommenda-
tions, including spare parts and other maintenance
support materials.
e. Procedures for carrying out maintenance tasks.
6. Engineering, architectural, functional flow, and block dia-
grams and text generated as a product of designing the plant
of concern.
3.1.2 Organize Plant Information
Background materials relating to plant design and its functioning can only
be effectively exploited if they are processed in some organized fashion.
Four steps help to organize plant information for purposes of functional
analysis:
1. Emphasize unit treatment. Unit process treatments such as
degritting, primary clarification, and anaerobic digestion,
form the most natural and convenient basis for organizing
plant functions.
2. Prepare functional flow diagrams. Such diagrams are a con-
venient way of summarizing the principal plant functions and
their interrelationships.
3. Use consistent nomenclature and codes. Analysis and des-
cription of plant functions can be impeded by failure to
establish and use a consistent scheme for easy reference to
functions. It is even more important to have an effective
way of indexing personnel functions to the plant functions
which they support.
4. Be aware of functional levels. The purpose here is not to
do an exhaustive analysis of the plant and its component
equipment. Rather, the purpose is to look at functional
characteristics of the plant down to a level of specificity
57
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which is useful in helping to identify required personnel
functions. Excessive detail is a detriment rather than a
virtue.
3.1.3 Derive Personnel Functions
Once plant functional information and supporting documentation are orga-
nized, personnel functions can be derived by systematic review of each
plant function. In general, this derivation is most effectively accom-
plished in the following sequence:
1. Derive operator functions. Operator functions tend to
emphasize treatment process monitoring and control. They
are closely linked to the central process functions (con-
trol loops) of the plant. The required operator functions
will be most immediately and obviously available from a
review of plant control functions. These operator functions
can, in turn, provide a useful frame of reference in deriv-
ing personnel functions less directly and obviously suppor-
tive of major on-line treatment processes.
2. Derive maintenance functions. Maintenance functions for
personnel are derivable largely from the design and opera-
ting characteristics of equipment. Both preventive and
corrective aspects of maintenance must be considered. Broad
categories of maintenance functions are periodic checking,
adjusting, troubleshooting, repairing, replacing, and serv-
icing (e.g., cleaning, lubricating, replenishing).
3- Derive support functions. Technical support such as engi-
neering and laboratory analysis, storekeeping, and custodial
services, are best derived from a joint consideration of the
plant performance characteristics and the previously identified
operator and maintenance functions.
58
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4. Derive management (administration and supervision) functions.
Though management functions are ultimately aimed at optimiz-
ing plant performance, they are importantly conditioned by
the operator, maintenance, and support functions through
which management must have its effect.
A worksheet for recording operator and maintenance functions derived from
plant functions is illustrated in Figure 10. As shown in Figure 10, it
is frequently useful to distinguish explicitly between personnel and
equipment functions—particularly for operator functions.
3.2 Describe Tasks
Personnel functions represent relatively broad functional requirements
which must be fulfilled by humans, but they do not provide details of
required worker activities and skills. Tasks are component parts of per-
sonnel functions and, through their description, a detailed definition of
worker requirements for meeting system functions is derived. Figure 11
reflects the place of task information in a hierarchy of work specificity
where system requirements are steadily branched into successively more
detailed human involvement.
The accomplishment of this step is centered around the following individ-
ual substeps, normally approached in serial fashion:
3.2.1 Identify tasks.
3.2.2 Describe activity requirements.
3.2.3 Describe critical activity characteristics.
3.2.1 Identify Tasks
The identification and enumeration of tasks is aimed at identifying dis-
crete groups of behaviors directed toward the outcomes specified by per-
sonnel functions which are themselves a specifiable outcome required to
59
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Plant
Function/Subfunction
Personnel Function
Equipment Function
1. Monitoring quality
of discharge water.
l.a. Monitoring pH
of discharge
water.
l.b. Monitoring of
BOD in
discharge
water.
I.e. Etc.
2. Suspended solids
removal.
2.a. Grit removal.
2.b. Etc.
Collection of samples from discharge water.
Operation of pH instrumentation.
Recording pH values in log.
Preventive maintenance of pH instrumentation.
Corrective maintenance of pH instrumentation,
Collection of samples from discharge water.
BOD analysis on discharge samples.
Recording analysis results in log.
Preventive maintenance of grit chamber.
Corrective maintenance of grit chamber.
Operation of flow control valving.
Operation of emergency bypass valving.
Disposal of grit.
Automatic pH analysis
with direct reading
scale.
Separation of grit
from input flow.
Figure 10. Worksheet for Allocating Plant Functions and Subfunctions
to Personnel Functions and Equipment Functions.
-------
The Plant
Wastewater Treatment Plant
Plant Functions
[Suspended
Solids
Removal
Etc.
1
Personnel and
Equipment Functions
Personnel Functions
Equipment Functions
Personnel
Functions
!•••••••••*•«
Tasks
•••••••••••••*•••••••*•••«••
Task Steps
(Individual
Activities)
Lubricate Pump #1
Lubricate Pump #2
Clean Grease Nipple
Attach Grease Pump Fitting
Human Motion
Reach with Right Hand
Figure 11. Relationship of Tasks to a Hierarchy of Work
Requirements in a Wastewater Treatment Plant,
61
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meet plant treatment objectives and criteria. In identifying the required
tasks, emphasis is placed on relating personnel functions to the units of
equipment or operations with which functions are to be performed.
As an aid to the enumeration of tasks, it is recommended that a matrix
task inventory be prepared for each personnel function involving direct
interaction with equipment or other tangible features of the plant. The
matrix task inventory helps in the identification of tasks by testing the
appropriateness of potential action verbs against a listing of the known
hardware objects associated with a personnel function. A list of task-
related action verbs is arranged along one axis of the matrix and the
tangible objects along the other. The object list, which should be readily
available from the equipment listing and detailed specifications of the
previous step, should include every object to be acted upon in some way
by a person. The list of objects would thus encompass forms, supplies,
instruments, tools, and any other objects associated with a personnel
function in addition to the primary plant equipment around which the per-
sonnel function is centered.
Some examples of action verbs which might be appropriate to a preventive
maintenance personnel function are: check, adjust, lubricate, replace,
clean, align, calibrate, and disassemble. The complete list of action
verbs can be expected to vary considerably for each personnel function,
although there will also be a tendency for some actions to be applicable
to a great many personnel functions. For an administrative function, some
appropriate action verbs might be: evaluate, compute, compose, edit, re-
view, and inventory. For an operations function, they might be: observe,
measure, regulate, adjust, activate, compare, etc. Because both the ac-
tions and objects will be different for each personnel function, it will
be necessary to develop a separate matrix for each personnel function.
After entering the object and action verbs along their respective axes of
the matrix, examine each object and action verb possibility to determine
if someone does, or might have to, perform this action for this object.
62
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It is recommended that the following three operations be carried out with
the matrix:
1. Consider each object in turn and step through the action
verbs listed along one axis of the matrix, making decisions
as to whether someone will have to perform the indicated
action for that object. Place an "X" in the cell if a par-
ticular object requires that action or a dash (-) if the
object does not require that action. In case of doubt,
leave the cell blank until it can be definitely determined.
2. After testing all of the actions against the first object,
determine if additional actions are appropriate, and if so,
enter them. Consider the next object against all the actions
and again add any new actions to the matrix, but be sure to
consider the new actions against the previous object(s).
Continue the process through all of the objects.
3. After completing the testing of actions against objects,
check the overall matrix to ensure that certain actions
have not been repeated in slightly different forms. For
example, installing a filter would involve removing the old
one and replacing it with a new one. It would be misleading
to have all three of these actions "checked" in the matrix
when the removing and installing actions might better be
considered parts of the replacement process. Choose that
action verb that best describes the actual activity and
refrain from including subordinate or repetitive entries.
These same operations are carried out for each personnel function. The
final result of the effort should be a comprehensive listing of tasks
(actions and objects) for the entire plant. Figure 12 provides an example
matrix task inventory of an operations and maintenance personnel function.
63
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Function: Maintenance of Lift Station
o
Dry Wells 1 & 3
X
Centrifugal Pump
x
X
Ejectors
Controls
X
Check Valves
X
X
X
X
Trash Racks
Bar Screens
X
X
PM Re
Dosing Tanks
Distributors
Drain Valve
Air Relief Pipes
Recirculation Control
Function: Operation of Standard Rate Filter /
X
X
X
X
X
Figure 12. Examples of the Task Inventory Matrix
for a Maintenance and Operations Function.
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3.2.2 Describe Activity Requirements
Task activity requirements represent "what" a worker roust do to perform a
task in terms of the individual activities, or steps, required. Further,
activity requirements are intended to reflect "how" a worker knows when to
initiate a task and detect that the task has been successfully completed.
In brief, the activity descriptions specify, along an operational time
scale, the cues that personnel should perceive and the related responses
they should make. A task activity description must be developed for each
task and must include the following information in detail.
1. Task title. Each activity description must be identified
by an unambiguous task title. Where there are redundant
tasks (for example with duplicate units of equipment),
there is no need to repeat descriptions, but inconsistent
task titles could easily lead to unnecessary effort and
confusion. If a matrix task inventory was used, the com-
bination of verb and object derived through this process
is generally sufficient. Examples might be "lubricate
centrifugal pump #14" or "clean trash rack."
2. Start cue. The start cue is the information or signal which
initiates the activities performed by the task. For a task
which is part of an operations function, for example, the
start cue may be an observed condition of wastewater passing
through a treatment process, a meter reading of particular
value, a laboratory report, or an oral message. Control
parameters and control loops (Chapter 2) represent a valuable
source of such information, as do detailed equipment speci-
fications which provide maintenance information such as fail-
ure symptoms and preventive maintenance schedules.
3. Action statements. Action statements convey the human activ-
ities, or steps, required for task performance. Individual
action statements are much like task titles in that they
65
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convey action through a verb and the objects acted upon.
Here though, the verb describes a unitary behavioral activ-
ity and not a collection of activities. The choice of verb
must be behaviorally oriented. Behavioral verbs are dis-
tinguished from movement verbs in that they more clearly
denote the intellectual process rather than the physical
action. Behaviorally oriented verbs are exemplified by
detect, identify, align, recognize, interpret, compute, and
classify. The use of movement verbs should be avoided; they
tend to result in extremely detailed descriptions which later
require systematic "synthesis" in order to derive useful in-
formation for operational planning.
4. End cue. The purpose of the end cue is to indicate that the
task has been properly completed. Here, the emphasis is
upon effects of the task behavioral actions, rather than the
behavioral actions themselves. If the task is to lubricate
a pump, the end cue refers to the conditions that indicate
that the pump has been properly lubricated. If the task is
to adjust a flow control valve, the end cue may be that a
flow instrument reads a particular value, or that water
reaches a certain level in a tank or sump. The end cue is,
in many respects, a standard of qualitative performance, a
goal for task performance, and required knowledge for per-
formance of the task.
5- Required tools. A listing of tools and auxiliary equipment
necessary for performing task activities is important to
the description. In particular, special tools and equip-
ment with which personnel may not be familiar must be noted.
Electronic test equipment and water analysis instruments,
for example, can place significant additional activity
requirements within the context of task performance.
66
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6. Task location. Note where the task is performed. For main-
tenance tasks especially, there is the possibility that task
activities can be performed either on-line or off-line (in
a central shop facility), which would undoubtedly have some
impact on the conditions under which activities are performed.
3.2.3 Describe Critical Activity Characteristics
Another class of task activity requirements, which support and complement
the preceding, pertains to more purely Qualitative aspects of task perform-
ance and levels of skill and knowledge. The description of this class of
activity requirements is aimed at defining critical dimensions and values
which must be achieved by a worker if his performance of a task is to be
considered acceptable. While activity descriptions state what the worker
must do, the critical characteristics of activities define "how well" the
task must be performed, provide insight to required skill and knowledge,
and provide quantitative dimensions to task performance. The following
represent critical aspects of task performance to be included in task
descriptions.
1. Decisions or diagnoses. It must be determined if there are
decisions or diagnoses which must be made as a part of the
task performance. Are there alternatives based on the same
start cue? If there are decisions to be made, what is the
basis for the decisions? Brief statements should be sup-
plied as part of each task description to reflect what
options are available and the basis for making the decision
or diagnosis.
2. Task frequency. Task frequency is a measure of how often
the task must be performed per unit of time. Scheduled
tasks, such as the submission of monthly reports to state
and local health departments, are easily identified and
pose no real problem. Unscheduled tasks, such as with the
67
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corrective maintenance of equipment, are more difficult
to accurately specify. In such cases, an estimate of fre-
quency will have to be made on the basis of data from
similar system equipment, expert judgments, and knowledge
of equipment reliability. In all cases, however, it is
important to note whether the task is scheduled or unsched-
uled. This information has important implications for
deriving quantitative personnel requirements and for train-
ing.
3. Task time. Task time represents a measure of the time
necessary to perform the task. There are two important
time parameters which must be derived as part of the task
description. One parameter of task time reflects the task
requirements necessary for meeting system objectives; that
is, the system may be degraded if the task cannot be per-
formed within some time limit. The other parameter per-
tains to the average amount of time required for perform-
ance of the task by a properly qualified person. Obviously,
the average actual time must always be less than the "system-
imposed" time if system objectives are to be achieved. The
system-imposed time provides a check on system design while
the actual average time represents valuable information for
job design, staffing guides, and other planning activities.
Average actual time should be based on the length of time
between a task start cue and that point at which the person,
or team of persons, would be available to begin another
task. That is, the time required to pick up tools, clean
up the work area, return tools, and so forth should be
included in the time measure.
Average task time, to be even reasonably accurate, should
be based on the "time-study" and "work-sampling" techniques
68
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employed extensively in the fields of psychology and indus-
trial engineering. The United States Department of the Navy
(1967) has outlined many appropriate techniques for such
measures, as have many other institutions and authors. There-
fore, detailed procedures are not incorporated here.
During some stages of plant development, there will be no
opportunity for measuring task time since the tasks are not
being performed. In such cases, it is appropriate to utilize
time measures which might be available for similar tasks in
operating systems. Inquiries for such data should be made
to EPA's Division of Manpower and Training. If data from
other systems are not available, it will be necessary to
estimate task performance times. Estimated times should be
later reexamined and revised until sufficient operational
status has been developed to permit measurement of standard
times.
Caution is in order for the measurement of task performance
times in Demonstration Plant situations because the personnel
involved at this level are often more qualified and experi-
enced than can be expected at a typical treatment plant.
Because an engineer can perform a task in a certain period
of time does not mean that the expected treatment plant popu-
lation will be able to perform in that time, even with ade-
quate training and experience.
4. Memory requirements. Must the task be performed from memory
or is there some built-in provision for guiding the activi-
ties of a worker?
5. Special behaviors. Are there special behaviors required for
performing the task? These represent critical behaviors for
task performance and are of such a type that not everyone in
the population could be expected to perform them adequately.
69
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Examples might be "mentally adding a series of ten, two-
digit numbers" or "lifting a 100-pound bag of chemicals
above the shoulder."
6. Coordination requirements. Are there physical coordina-
tion requirements that not everyone in the population could
be expected to perform adequately?
7. Special environments. Are there environmental conditions
associated with task activities which might have a signifi-
cant impact on task performance? Cold outdoor weather is
an example.
8. Likely errors. Are there situations within the structure
of task activities where errors are likely, and if so, what
are they and what is their impact on system functioning?
9. Task criticality. Would failure to perform this task at
the appropriate time and within stated tolerances of time,
or quality, result in failure to meet system objectives?
Also, would an error in task performance jeopardize achieve-
ment of system objectives? A three-point numeric scale is
frequently used to indicate the level of task criticality.
10. Hazards involved. Are there any hazardous situations which
might be encountered through performance of task activities,
such as toxic fumes, falls, fire, electricity, etc.?
11- Number of personnel. Can the task activities be performed
by one man or is a team effort and coordination between team
members required?
There are three commonly used formats for recording task data. In brief,
they are: verbal descriptions, tabular formats, and flow charts with sup-
porting information. Verbal descriptions are seldom used because data
extraction is difficult, and, for large systems, the approach is bulky
and unwieldy. Tabular approaches offer the advantages of relative
70
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compactness and easy extraction of data; they are also quite adaptable to
a variety of situations. The flow chart method of description can be
bulky and awkward as a working document, but offers advantages for the
analysis of critical human performance requirements. It is recommended
that the tabular format be used, but a verbal or flow chart format might
well be used in support of particularly complex or critical tasks. Figure
13 represents a starting point for the recording of task descriptions
intended for use in operational planning.
There will be a considerable amount of personnel data available when these
facets of task description are completed. Adequate description of person-
nel requirements dictates the need to present task data in a manner which
will facilitate the conversion of "what has to be done" to "what kinds of
people are required and how many." The final task-personnel requirements
must, therefore, be developed into formats which will permit easy extrac-
tion of personnel information as input to other activities, serve as an
overall vehicle for communicating task information, and form a permanent
record for possible future use in other system efforts.
Subsequent analysis of task information is heavily dependent on being able
to pull task information together according to commonalities of one type
or another. A classification code should be assigned to each task descrip-
tion which will permit all tasks to be cross tabulated along as many
dimensions as possible. At a minimum, it should be possible to compile
tasks according to system and personnel functions.
3.3 Describe Positions
Positions represent units of work comprised of one or more tasks which must
for practical purposes, be performed by a single person at a given location
within the plant. The design and description of positions is the initial
stage of job design, which has as its goal the differentiation and aggre-
gation of tasks in such a way as to optimize the ultimate efficiency,
effectiveness, and economy of the plant staff.
71
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Funrtinn
Task Titl
WORKSHEET FOR TASK DESCRIPTION
~ L.fi. S
oa, r
Function No.
Task No
Task f>iHraiity A/C.-J tLr-', h', (^ J I ' <3
Fvpqnpnry >/iO jXv5
Start CUP ( <= ) PW .-SW^-c^ /e. ^ A . f> A n'.
System-requi red Time
Average Timp o- ,-Shr.
no , • .<>
End
-f (ire. *c.se. S
Occupational Area
Skill Level.
Code
Action Description
Remarks (contingencies,
decisions, cautions, references)
• 3
6.
7
S"
ti c . t-..d <£.
.'YTc.t.i" 0 T(.
y
IF c/,
.p^ (i./0-.i <~i. i/i ilcti-i.
,';e. tf . t)i i"K -x/o .' A;'
'
.M p ,
Sy/viptc/vjs of
>'U_tt'.
Figure 13. Sample Format for Task Description.
72
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3.3.1 Identify Li nkages
Tasks are combined into positions largely on the basis of inter-task link-
ages which serve to enhance overall work performance. Important task
linkages to be identified include the following:
1. Equipment linkages. The nature of equipment (the object[s]
acted upon) forms a primary relationship between tasks.
Commonalities in equipment and tools are generally indica-
tive of heavy transfer of skill and knowledge from one task
to another, thereby fostering the development of worker
capabilities. Equipment linkages should consider not only
the tasks performed on identical units of equipment, but also
equipment with similarities of design and operating princi-
ples .
2. Facility linkages. The design of the physical plant facility
and the location at which tasks are performed have a direct
bearing on work efficiency. The physical separation of tasks
poses travel and logistics problems, resulting in a loss of
productive time, when tasks cannot be ordered into a short,
closed loop of travel activity.
3. Communications linkages. The communication of required task
information, both input and feedback, has significant impact
on how tasks might best be combined. Increased efficiency
and reliability can generally be achieved by eliminating
or reducing redundant information transfer to more people
(positions) than is necessary. Task start- and end-cues, as
well as all required support information, should be carefully
examined for inter-task commonality.
4. Time-sequence relationships. Tasks having simultaneous or
sequential performance relationships to each other are a
strong influence on how tasks can or cannot be combined.
73
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Obviously, two tasks cannot be performed simultaneously by
the same person, and therefore cannot be parts of the same
position. Where sequential task performance is dictated,
there is the possibility of gain through assignment to a
single position.
5. Homogeneity of skill and knowledge. The type and level of
skill and knowledge required for tasks is important to ensur-
ing satisfactory performance and to motivation and training
factors of the personnel organization. In general, tasks
within a position should represent a high level of skill and
knowledge homogeneity. Task criticality, level of training
required, limits on task performance time, error consequences,
memory requirements, and physical skills are some of the task
characteristics which, in combination, assist with making
judgments about inter-task commonalities of required skill
and knowledge.
3.3.2 Cluster Tasks
Positions are structured by aggregating tasks into operationally meaningful
combinations. The term applied to this process is "task clustering," which
seeks to capitalize on task linkages as a means for developing meaningful
combinations.
Task clustering requires considerable manipulation of task and task linkage
information. Reiterative sorting of tasks into tentative clusters, and the
testing of clusters against appropriate criteria, is carried out until the
maximum number of criteria are satisfied both qualitatively and quantita-
tively. In general, the criteria for clustering tasks into positions
should include:
1. Common functions or objectives.
2. Location of task performance.
3. Timing sequence of task performance.
74
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4. Equipment utilization.
5. Common skill and knowledge requirements.
6. Common capability requirements.
7. Task time requirements.
8. Nature of the task in terms of its frequency of performance,
priority, and criticality.
3.3.3 Define Performance Implications
The performance implications of positions are carried, in the main, by the
component tasks of that position. However, within a particular position
configuration, there is the possibility .that the combination of tasks
will have an effect on required and/or expected performance. Each tenta-
tive position should be carefully examined for interactive performance
implications of tasks and, where necessary, adjustments made to enhance
position performance. Adjustments can be made either to the assignment
of tasks to a position or to the specific situations which induce the
performance decrement.
Some of the questions to be answered in defining performance implications
include the following:
1. Does the position provide for performance of all emergency
situations which can be feasibly anticipated without con-
flict? That is, is there a task scheduling conflict which
might hamper position performance under specific conditions?
2. Do tasks within a position violate any imposed standards or
union jurisdictions?
3. Does the distribution of tasks to positions provide for the
standby or take-over of positions without serious deterioration
of performance? Sickness, accidents, and normal leave time
may necessitate the transfer of position responsibility to
another person.
75
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4. Is there sufficient variability in the performance times of
tasks within the position that position performance might be
degraded through overloading?
3.3.4 Defi ne Affective and Motivational Factors
It is expected that the first approximations to job positions will be based
primarily on strict performance considerations. However, once preliminary
positions have been defined, motivational and morale factors can no longer
be ignored. Define motivational and morale factors for each position and,
if necessary, restructure positions to yield improved worker motivation
and morale.
While the principles of task clustering previously described were aimed
primarily at optimizing position functioning, another set of principles
can be effectively used as a test for motivational factors. Four princi-
ples which will assist in identifying worker motivational factors with
respect to positions are:
1. Tasks requiring responsibility or authority for assigning
personnel, for distributing work, for evaluating work, for
making decisions, for handling emergency situations, and
for generally taking charge of a situation, should be
assigned to several positions of increasing responsibility
rather than to only one position (principle of supervisory
structure).
2. Tasks assigned to a given position should keep the man busy
(principle of time utilization).
3. Tasks assigned to a given position should avoid excessive
repetition (principle of self-esteem).
4. Positions should be related to other similar positions
where the primary difference is the level of skill and
knowledge required, so that progression is possible (and
76
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obvious) from relatively routine positions to positions
of substantial responsibility and authority involving
similar tasks (principle of worker progression).
3.3.5 Prepare Position Descriptions
Since a job is comprised of one or more positions, position descriptions
represent the principal tool through which jobs will ultimately be struc-
tured. As such, the position descriptions must contain the qualitative
and quantitative information to permit the rational development of jobs.
The position description is a summary of the task information encompassed
by the position, characterized by the following four essential elements:
1. Task enumeration. The tasks included within the position
should be enumerated by task code number and task title.
List the tasks, to the maximum extent possible, in the order
in which they are performed.
2. Time dimension. Itemize the task performance times and the
frequency of performance for each entry. Multiply frequency
by performance time for each task and then sum to derive a
total time requirement for the position. The time require-
ment should be expressed in man-hours per week, which will
require the reduction of task frequencies to a common denom-
inator-prior to the summation process.
3. Skill level estimate. To assist with the combining of posi-
tions into jobs, a skill level estimate should be assigned
to each position description. A three-level numeric scale
is generally sufficient to cover the range of required skill.
The scale should be indicative of the levels of skill one
might develop through: (a) on-the-job familiarization, (b)
limited formal training, or (c) considerable formal train-
ing.
77
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4. Occupational area. An early estimate of the occupational
area of which the position would be considered a part should
be entered on each position description. This can be facil-
itated by entering the personnel functions to which each
position applies.
3.4 Describe Jobs
Jobs represent one or more job positions which, for practical purposes, are
carried out by a single individual. Job responsibility is centered around
the sum of the tasks encompassed by each job position. The purpose of job
description is to present a concise picture of the qualitative personnel
requirements to be fulfilled through the hiring and training of a plant
staff.
3.4.1 Cluster Positions
Just as tasks are rationally organized into job positions, job positions
are clustered into units of work to represent that which must be performed
by a given individual within the plant. The total work assigned to an indi-
vidual is called a job. The clustering of job positions into jobs is carried
out through much the same process as was used for the clustering of tasks.
The linkages which apply to the clustering of tasks also apply to the
clustering of positions. In addition, the clustering of positions into
jobs should seek to structure required work into efficient and least-cost
personnel assignments. Toward this end, the clustering of positions should:
1. Maximize utilization of existing personnel classifications
and job organizations, but not to the point of forcing
unique requirements on a person or jeopardizing system
efficiency and cost-effectiveness.
2. Minimize initial and update training requirements.
78
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3. Minimize the spread of complex skill, knowledge, and pro-
ficiency requirements across personnel except as might be
necessary to create an effective career hierarchy.
The clustering of positions must take careful consideration of quantitative
aspects to prevent the overloading or underloading of work assignments.
3.4.2 Prepare Job Descriptions
Job descriptions are the principal means for expressing the qualitative
dimension of required personnel. A separate job description must be pre-
pared for each unique combination of job positions. The descriptions serve
to present the conclusions and recommendations of the job design effort
and as a product to guide the hiring, training, and career structure of
the plant personnel organization. Because of widespread applications for
job descriptions in specific plants, and the overall developmental cycle
of treatment plants generally, it is important that the descriptions follow
standard formats and principles of development.
A complete and meaningful description of required jobs is dependent on
definition of at least the following job elements:
1. Job title.
2. Functions performed by the worker.
3. Indications of required training.
4. Significant aptitudes required by the job.
5. Significant interest associated with the job.
6. Significant temperaments associated with the job.
7. Critical physical demands of the job.
8. Working conditions of the job.
9. Enumeration of the positions and tasks of the job.
The desired format for job description must necessarily be closely aligned
with the specifications adopted by the United States Department of Labor,
which are the most widely recognized and used form of definition for plan-
ning and development purposes. The Dictionary of Occupational Titles (DOT),
79
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produced by the Department of Labor, serves as a standard reference for
development of job descriptions in operational planning. The only excep-
tion to DOT format is the additional requirement for enumerating positions
and tasks.
The procedural technology and development of job descriptions, as well as
required formatting, is significantly detailed and has therefore been
relegated to a separate section of this Guide. Appendix A provides com-
prehensive guidance to the development of job descriptions.
3.5 Describe Staffing
Staffing denotes how many people are required to adequately man the treat-
ment plant. The conventional means for expressing this quantitative dimen-
sion is through staffing plans, which account for the number of people
required to serve in each job title. The quantitative dimensions of tasks,
positions, and jobs are translated into "real people" by the staffing plan.
3.5.1 Identify General Oi ten'a
Staffing of a given plant will be influenced by prescribed general cri-
teria. These criteria must be identified and their impact assessed prior
to the development of a staffing plan. Some representative general criteria
are as follows:
l- Shifts. The number of shifts will influence the total number
of personnel required in each job. It can be assumed that
municipal treatment plants will operate 24 hours a day, but
there is a great deal of latitude in what personnel functions
can be fulfilled within a single 8-hour shift and those which
require more or less around-the-clock personnel inputs. The
degree of automation, the size of the plant, and local prac-
tices with respect to "on-call" personnel are but a few of
the possible factors bearing on required job shifts.
80
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2. Days per week. Some personnel functions must be fulfilled
7 days per week while others can normally be fulfilled within
a normal 5-day work week. Operations functions, for example,
generally dictate 7 -day requirements while administrative
functions can most often be served in a 5-day week.
3. Minimum personnel. Federal, state, and other regulatory
agencies have set forth minimum personnel recommendations
for certain sizes and types of treatment plants. These
recommendations should serve to guide the staffing for
individual plants. The Federal funding of plant construc-
tion, for example, is contingent upon certain minimum per-
sonnel staffing criteria.
3.5.2 Estimate Worker-Hour Requirements
Estimate the total man-hours required for each job title during each appli-
cable shift. This can be facilitated by summation of the quantitative
values assigned to each position incorporated into the jobs. Temper these
estimates with other performance time estimates which may be available,
including:
1. Utilization of data accumulated from other similar jobs
and job positions.
2. Time measures of simulated or actual work performance.
3. Best judgments by job analysts, technical experts, and/or
experienced workers in jobs with similar requirements.
3.5.3^ ^Estimate Worker Requirements
Estimate the number of persons required in each job by dividing the shift
man-hour requirements by the number of hours in a shift (rounded upward to
the nearest whole number) and summing across the required number of shifts.
This first estimate must then be increased to compensate for vacations ,
81
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sickness, and other "shift implications1' such as 7-day functional require-
ments. On the other hand, the first approximation might be decreased
somewhat through the redistribution of task and position assignments. For
example, initial staffing estimates may indicate one job is slightly over-
loaded for one person while another is significantly underburdened and,
through minor task redistributions, acceptable loading is found possible
without the additional staff member originally indicated.
3.5.4 Derive Dual Values
It is characteristic of wastewater treatment plants that not all personnel
required for their effective, sustained operation are engaged full time in
their functioning. This, combined with the added complexity that some jobs
are required on multiple shifts and others on only one shift, makes it
desirable to present two related but separate quantitative estimates for
each job:
1. The total number of personnel to be involved.
2. The total number of man-hours for a specified unit of time
(most typically a week).
It is not uncommon for municipal treatment plants to borrow required man-
power from other municipal services, particularly when the requirements are
minimal or there is only an occasional need. Similarly, it may be more
economical to contract certain services than to have in-house capabilities.
Note any such instances so that they may be incorporated into the staffing
plan.
3.5.5 Prepare Staffing Plan
The staffing plan should consolidate the total staffing requirements of
the individual plant into a brief but concise summary description. The
recommended regular plant staff, as well as any part-time or contracted
resources, are listed by job title and the number of persons required in
each job. A sample staffing plan format is presented as Figure 14.
82
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Staffing Plan for Plant Number —,
Sanitary District,
, Pennsylvania
Func-
tional
Area
0)
\ -H
>i -P
M tO
O SH
W -P
•H U)
> -H
M fi
0) -H
ft e
3 T)
W ft,
\
(0 W
M C
0 O
ft -H
O -P
0)
u
c
rd
fi
0)
-P
fi
-H
(0
s
1 H
£! tO I -p
U 0 ft in
Q) -H P O
H C CO ft
S-l
0) 1 -P
,£ ft ^
-P 3 O
O W ft
Job Title
Superintendent
Asst. Superintendent
Operations Supervisor
Shift Foreman
Maint. Supervisor
Maintenance Foreman
Clerk Typist
Operator I
Operator II
Auto. Equip. Operator
Mechanic I
Mechanic II
Electrician I
Electrician II
Maint. Helper
Painter
Chemist
Laboratory Technician
Storekeeper
Custodian
Laborer
TOTAL STAFF
Number Persons/Man-Hours Per Week
At estimated flow
of 20 mgd at
Plant Startup
1/40
1/20
a/13
1/20
a/13
a/13
1/40
4/140
6/168
1/30
1/40
1/20
1/20
1/40
2/80
a/10
a/30
1/40
a/20
1/40
3/100
26
At design
flow of
35 mgd
1/40
1/30
a/20
1/20
a/20
a/20
1/40
5/160
8/200
1/40
2/60
1/30
1/40
1/40
3/100
a/ 10
1/40
1/40
a/20
1/40
3/120
32
Note: Staffing indicated in terms of the number of men assigned;
the second value indicates the number of man-hours per week.
The letter "a" represents personnel functions fulfilled by
drawing, upon other municipal employees, contracted services,
or other "outside" resources.
Figure 14. Sample Format for Staffing Plan.
83
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3.5.6 Cross-Check Values
As a check on the quantitative values presented in staffing plans, it is
recommended that staffing guides be consulted. These documents are avail-
able through EPA's Division of Manpower and Training for many conventional
treatment processes and a variety of general treatment plant types and
sizes. The staffing guides can be used to help structure the staffing plan
and as a means for comparing values specified for a particular plant with
those which represent an average of various plant design configurations.
Do not bend the values obtained through your job and task analysis to fit
those of the staffing guide; the staffing plan is tailored to fit the
requirements of the specific plant, and it can be expected that values are
going to differ. Become suspicious of the values you have generated only
if they appear unreasonably divergent from staffing guide values. In other
words, use the staffing guides as a check, not as a set of specifications.
Request copies of staffing guides through:
Manpower Development Staff
Office of Water Program Operations
Environmental Protection Agency
Washington, D. C. 20460
Table 3 reflects at least a sample of the quantitative data currently avail-
able in the form of staffing guide information. The information presented
in staffing guides represents the minimum, or criterion, number of person-
nel required to manage, operate, and maintain particular types of plants
in an effective manner. As can be seen in Table 4, there is considerable
latitude in personnel requirements as a function of both plant type and
hydraulic loading.
At least for conventional forms of primary and secondary treatment, the
total staffing should fall within the boundaries described by the two
curves of Figure 15. Primary plants with low-labor forms of sludge dis-
posal represent the low end of the scale and activated sludge plants with
incinerators for sludge disposal represent the high end. Plants with
84
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Table 3
Illustrative Staffing Guide Information for Conventional
Treatment Plant Types and a Range of Hydraulic Loadings
Total Manpower Requirements per Plant as Function of Flow
Plant Type
PRIMARY with:
Digesters and Lagoons or Dry-
ing Beds
Digesters and Vacuum Filters
Vacuum Filters and Incinerators
TRICKLING FILTER with:
Digesters and Lagoons or Dry-
ing Beds
Digesters and Vacuum Filters
Vacuum Filters and Incinerators
ACTIVATED SLUDGE with :
Digesters and Lagoons or Dry-
ing Beds
Digesters and Vacuum Filters
Vacuum Filters and Incinerators
Flow (mgd)
1
4.0
4.0
4.0
5.0
5.0
5.5
6.5
7.0
7.0
3
5.5
6.0
6.0
7.5
8.0
8.0
9.5
10.0
10.0
' 5
7.5
7.5
8.0
10.0
10.0
10.5
12.5
12.5
12.5
10
9.5
11.5
11.0
12.0
15.0
15.0
16.0
19.0
18.0
Uso^J
20
14.5
17.5
17.5
19.5
24.0
24.0
24.0
29.0
27.0
35
22.0
26.0
26.0
29.0
36.0
36.0
35.0
42.0
41.0
50
29.0
35.0
33.0
37.0
45.0
48.0
45.0
53.0
53.0
65
34.5
41.5
41.0
46.0
55.5
55.5
54.5
66.5
64.5
80
41.5
49.0
49.0
54.0
65.5
68.5
63.5
75.5
74.5
100
48.0
57.0
57.0
63.5
77.5
81.5
73.0
88.0
90.0
oo
Adapted from data produced by Black and Veatch Engineers, Kansas City, Missouri.
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Table 4
Sample Staffing Guide with Distribution of Staffing
Across Representative Occupation Titles
Staffing Criteria for Activated Sludge Treatment Plants with Vacuum Filters and Incinerators
(Ba-sed on 3 shifts and 7 day/week)*
Occupation Title
Superintendent
Assistant Superintendent
Clerk Typist
Operations Supervisor
Shift Foreman
Operator 11
Operator I
Automatic Equipment Operator
Maintenance Supervisor
Mechanical Maintenance Foreman
Maintenance Mechanic II
Maintenance Mechanic I
Electrician II
Electrician I
Maintenance Helper
Laborer
Painter
Storekeeper
Custodian
Chemist
Laboratory Technician
Total Staff
Plant Average Day Capacity in mgd
1
2.0
4.0
1.0
7.0
3
.5
3.0
5.0
.5
1.0
10.0
5
.5
4.0
6.0
•
1.0
1.0
12.5
10
1.0
4.0
6.0
1.0
1.0
.5
1.0
2.0
1.5
18.0
20
1.0
1.0
5.0
9.0
2.0
1.0
1.0
2.0
3.0
-
2.0
27.0
35
1.0
1.0
1.0
1.0
8.0
12.0
1.0
1.0
2.0
2.0
1.0
1.0
3.0
4.0
2.0
41.0
50
1.0
1.0
2.0
1.0
2.0
11.0
14.0
1.0
1.0
2.0
2.0
1.0
1.0
4.0
5.0
1.0
3.0
53.0
65
1.0
1.0
2.0
1.0
3.0
12.0
17.0
2.0
1.0
2.0
2.0
2.0
2.0
1.0
4.0
6.0
.5
1.0
1.0
3.0
64.5
80
1.0
1.0
3.0
1.0
3.0
15.0
19.0
2.0
1.0
3.0
2.0
2.0
2.0
1.0
5.0
7.0
1.0
1.0
1.0
.5
3.0
74.5
100
1.0
1.0
4.0
1.0
5.0
17.0
25.0
2.0
1.0
3.0
3.0
2.0
2.0
2.0
6.0
8.0
1.0
1.0
1.0
1.0
3.0
90.0
*Source: Black and Veatch Engineers, Kansas City, Missouri.
-------
Primary Plants
Digesters and
Drying Beds
Activated Sludge
Plants--Vacuum
Filters and
Incinerators
10
15 20 25 30 3,5 40
Minimum Total Personnel Requirements
45
50
Figure 15. Relative Range of Required Personnel for Conventional
Forms of Primary and Secondary Treatment Plants
87
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advanced treatments, as well as plants with an unusually low degree of
automation and mechanization, would likely fall somewhat out of the des-
cribed range and into the area of higher manpower requirements per unit
wastewater treated.
88
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4. PREPARE JOB AIDS
This chapter presents general procedures and principles concerned with
the development of job aids. A job aid is a device or document which stores
information necessary for work performance in such a way that it is readily
available and useful to workers as required on the job.
Job aids are aimed at extending worker capabilities through a reduction in
the need to mentally store and then recall job information. Appropriate
means for storing job information range from manuals of job information
and instructions to terse reminders of information elements to "cue" the
worker at the task location. Some examples of job aids include checklists,
tables, arrows showing direction of flow in pipes, and labels indicating
tolerances for control settings and status indicators.
The preparation of job aids, as described here, involves the following seven
major steps:
4.1 Verify the data base.
4.2 Assess the need for information support.
4.3 Structure information needs by_ positions/jobs.
4.4 Sequence information needs.
4.5 Determine functions served by information.
4.6 Determine units and formats for information support.
4.7 Design and test aids.
Some of the relationships of these steps to each other and to sources of
information are suggested in Figure 16.
4.1 Verify the Data Base
Plant information and data help to define needs for aids, structure aids,
and provide content for aids. The job and task information (whose organiza-
tion and preparation is described in the previous chapter) is central to
89
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Management
Documentation
4.1 Verify
Data Base
Technical
Documentation
APPENDIX B
Job Aids for
Managers
APPENDIX C
Job Aids for
Operators
4.2 Assess
Need for
Information
Support
I
4.3 Structure
Information
Needs by
Positions/
Jobs
4.4 Sequence
Information
Needs
i
1 '
4.5 Determine
Functions
Served by
Information
4.6 Determine
Units and
Formats for
Information
Support
I
4.7 Design
and Test Aids
Effective
Aids to Work
Performance
Figure 16. Principal Steps in the Preparation of Job Aids
-------
the design of job performance aids—both directly and indirectly through
its organization and focusing of other plant data. As a first step in
preparing job aids, review job and task information to ensure that:
1. Job and position descriptions have a complete delineation
of required tasks; that is, all significant areas of required
performance have been covered.
2. All tasks are accurately and completely described. It may
not be practical to describe in detail all of the varieties
of performance that can be exhibited by personnel faced with
varied contingencies—such as a manager involved in negotia-
tions with suppliers or a manintenance technician involved
in troubleshooting. The variety of conditions with which a
task is to cope and the nature of the effect of variation in
these conditions on task requirements can and should be
described, however.
3. All task steps are clearly within the capabilities of the
worker. Informational aids cannot, for example, compensate
for requirements which demand excessive reach or visual
acuity. The requirements must be made less stringent through
appropriate human engineering.
4. The intellectual (information processing) and memory require-
ments of all tasks can readily be inferred from their des-
criptions .
5. The job and task information can readily be related to
known characteristics of the prospective work force such
as formal education, demonstrated mathematical abilities,
and prior experience in wastewater treatment.
It is entirely appropriate that job and task descriptions include a great
deal of backup information about facilities, equipment, treatment processes,
and organization of the work force only by reference to documentation
91
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prepared for other purposes. Review such documentation to assure that
it does clearly support job and task descriptions fully and adequately.
Also, assure that the impact of described tasks on plant performance
characteristics (whose description is discussed in Chapter 2) is clear.
Such clarity is important for at least two reasons:
1. Selection of tasks to be supported by informational aids
can be guided by the probable impact on plant performance.
2. Design of individual aids should be oriented toward enhance-
ment of effective plant performance.
4.2 Assess the Need for Information Support
Not all worker activities will require job aids. An early step in prepar-
ing job aids should be to identify the specific worker activities (tasks
and task steps) whose performance can be improved through the use of job
aids. Review of each task, to identify job aid reauirements, should
include the following:
4.2.1 Assess the possible kinds of qrror.
4.2.2 Assess the probability of error.
4.2.3 Assess the maximum consequences of error.
4.2.4 Assess the probabilities of error detection.
4.2.5 Assess the distribution of consequences.
4.2.6 Assess the probable payoff from job aids.
4.2.7 Assess tradeoffs with job aids.
4.2.8 Define job aid objectives and specifications.
4.2.1 Assess the Possible Kinds of Error
Each significant job activity involves at least three aspects:
1. Perception—drawing information from the work environment.
2. Cognition--mentally processing perceived information to
guide work activities.
92
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3. Response—carrying out the overt biomechanical work require-
ments.
Consider perceptual, cognitive, and response errors separately. It may
also be useful to consider different kinds of error within each of these
classes. Perceptual errors include the following:
1. Attention errors include:
a. Inattention errors such as may be revealed by a
failure to monitor some important aspect of the
changing environment. For example, an operator
may fail to keep an adequate check on the quality
of sludge.
b. Misdirected attention errors such as may be
revealed by concentration on one aspect of the
job to the exclusion of other important aspects.
For example, a plant manager may be concerned
with operating costs to such a degree that he
fails to see substandard worker performance
which is having a detrimental impact on plant
effectiveness.
2. Detection errors involve incorrect perceptions of the envi-
ronment, even though the worker may be attending to the
appropriate parts of that environment. Detection errors
may be in any sensory mode (sight, sound, smell, feel).
They can involve both perceptions of current status and of
change characteristics. Detection errors include two prin-
cipal types:
a. False detection which involves the perception
of significant states or characteristics of the
environment which are, in fact, not present.
For example, a maintenance worker may read a
93
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test instrument during a routine check to indi-
cate an equipment malfunction when the equipment
is actually operating properly.
b. Detection failure which involves a failure on the
part of the worker to identify significant states
or characteristics of the environment. For exam-
ple, a plant manager may fail to perceive that a
daily plant performance report indicates that one
or more effluent measures indicates a below-
standard condition.
Cognitive errors include the following:
1. Evaluation errors which involve an incorrect interpretation
of input data with respect to one or more of the following:
a. Relevance, such that relevant data are judged not
to bear on a given issue or irrelevant data are
judged to bear. For example, a plant operator
may fail to see the relevance of high toxic metal
content for performance of biological treatment
processes.
b. Sufficiency, such that the worker judges informa-
tion which is adequate for selecting a course of
action, as inadequate; or, judges information which
is inadequate to suffice for guiding a choice, as
adequate. For example, a maintenance worker may
have enough information available to diagnose an
equipment failure exactly, but continue to make
redundant checks. Conversely, he may replace a
properly functioning component because he fails to
recognize that he has not eliminated all of the other
possible sources of malfunction, even though this
might be done with additional simple checks.
94
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c. Content errors are of two main types:
(1) Discrimination errors involve use of
classification schemes or measures
which are either too broad or too
specific. For example, a plant man-
ager may demand such specific per-
formance data that he is unable to
assimilate it. In contrast, he might
be satisfied with information that is
so broadly summarized that he is un-
able to use it to support effective
decision making.
(2) Classification errors involve the
assignment of data to the wrong class,
within whatever classification scheme
the worker is using. For example, an
operator may confuse a reading of one
parameter for another.
Memory errors can be in both long-term and short-term memory
Long-term memory tends to involve knowledge about the theory
underlying treatment and support processes, functional and
physical design of the plant, and work procedures. Short-
term memory tends to involve recall of information just re-
cently acquired from the work environment. Memory errors
take three main forms:
a. Omission errors involve a failure to remember needed
job information. For example, an operator may forget
a step in an equipment shutdown procedure.
b. Interpolation errors involve the intrusion of extra-
neous information. For example, a plant manager may
unnecessarily complete a report because he wrongly
95
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remembers that it is required by the district
sanitary engineer.
c. Falsification errors involve distortion of remem-
bered information. For example, a worker may
correctly read a meter, but then remember a wrong
reading.
Transformation errors involve faulty translation of informa-
tion from one form into another. It is sometimes useful to
distinguish at least two kinds of transformational error:
a. Procedural, which in turn includes two finer
classes:
(1) Rule selection in which the worker chooses
the wrong rule. For example, a worker may
use a linear transformation of his data
when a log transformation is appropriate.
(2) Rule following in which the worker does not
correctly follow the established rule. For
example, he makes a simple mistake in cal-
culation.
b. Logical, which includes two finer classes analogous
to those for procedural errors:
(1) Model selection in which the worker chooses
a faulty or inappropriate frame of reference
to guide his approach. For example, a plant
manager may use an inappropriate biochemical
theory in estimating the probable impact of a
new industrial hookup to the system.
(2) Reasoning^ in which the worker is not consistent
with whatever logical system he has chosen to
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follow. For example, a maintenance worker may
be inefficient in troubleshooting equipment
failures because he fails to eliminate all of
the alternatives which are possible from a
given series of checks.
Response errors include the following:
1. Selection errors involve choice of the wrong response. For
example, an operator may bypass a portion of influent during
an overload period even though he has more effective options
available to him.
2. Initiation errors involve some failure to start a response
as intended. They may include:
a. Timing, where the response is initiated either sooner
or later than is appropriate. For example, an oper-
ator may switch off a pump before a tank is fully
purged.
b. Sequence, where two or more responses are out of
order with respect to each other. For example, a
maintenance worker may remove an electrical safing
wire before activating equipment even though stand-
ard procedures call for a reverse sequence.
c. Deletion, where an intended response is not actually
initiated. For example, a manager may intend to tell
an operator about a change in work procedures but
fail to do so.
d. Insertion, where an unintended response is initiated.
For example, an operator may introduce a control
action which is irrelevant to the task at hand.
3. Execution errors involve inadequate consummation of an ini-
tiated response. They may include:
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a. Position, where some aspect of spatial location is
not properly handled in the response. For example,
an operator may set a control to an incorrect setting.
b. Direction, where some aspect of the response move-
ment does not follow a desirable path. For example,
an operator may turn a valve control in the opposite
direction from that intended.
c. Magnitude, where some aspect of response amplitude
is not within allowable limits. For example, an
operator may not depress a pushbutton far enough to
activate a circuit.
d. Duration, where a response is ended too early or
terminated prematurely. For example, a maintenance
worker may stop adjustment on a piece of electro-
mechanical equipment before it is fully aligned.
4.2.2 Assess the Probability of Error
An important factor in determining error probability is the frequency of
performance. Naturally, the more frequently a given activity is performed,
the greater the opportunity for errors in connection with that activity.
However, frequent performance of a given activity usually leads to an
increased familiarity with the information inputs and responses involved
in the activity. This familiarity can enhance reliable error-free per-
formance. There is one way in which familiarity can lead to increased
potential for error. Such increased error potential can result from link-
age of familiar information inputs with unfamiliar response requirements,
familiar responses with unfamiliar information, or (worst of all) familiar
information with familiar responses but in unfamiliar ways. For example,
an operator may have especially high error potential on a task where he is
required to increase biological activity by flow reduction if he usually
accomplishes this by increasing the supply of air.
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ich aspect of a job activity is subject to different error-inducing
ictors. Human engineering and some industrial design manuals are largely
'voted to a description of design features which impact on quality of
>rformance. In very general terms:
1. Perceptual error is increased by:
a. Weak intensity of the signal carrying needed informa-
tion. For example, a warning light may not be suffi-
ciently bright to alert the operator.
b. Inadequate contrast between the signal carrying needed
information and background "noise." For example, a
meter dial may be too close in color to the instrument
face plate.
c. Excessive rate of information change. For example,
the sensor on a particular process parameter may be
so sensitive as to set up a frequency of oscillation
that cannot be tracked by the observer.
d. Excessive complexity of information. For example,
information about multiple process parameters may
all converge on an operator at one time and without
a simple indication of which parameters are close to
a tolerance limit, making "state-of-the-plant" deci-
sions difficult.
e. Partial information. For example, a maintenance
worker who receives an incomplete report of malfunc-
tion symptoms is more likely to misdiagnose equipment
troubles than if he receives a full report.
2. Cognitive error is increased by:
a. Ambiguous relationships between input information and
response requirements. For example, a manager is
much more likely to take appropriate corrective action
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when his plant is not performing up to design capa-
bility if he has a clear indication of the relevant
alternatives available to him than he is otherwise.
b. Ambiguous rules for translating information input
into appropriate responses, especially if the worker
is to achieve multiple criteria. For example, a
manager who is expected to achieve maximum plant
performance and minimize cost must have clear trade-
off rules if he is expected to maintain a reasonable
balance.
c. Complex relationships between input information and
required responses. For example, an operator is much
more likely to make a mistake in choosing the right
response if it is conditional upon a number of possi-
ble contingencies in the external environment than
if he always makes the same response to a given process
status.
d. Memory demands, especially if they are specific and do
not include convenient cross-checking. For example,
an operator decision which is based on a remembered
series of instrument readings is very likely to be based
on at least partially incorrect information.
Response error is increased by:
a. Similarity of response alternatives, especially if the
number of alternatives is large and/or the options are
not well defined. For example, a worker is most likely
to flip the wrong switch when he is faced with a panel
of similar-appearing switches.
b. Stringent physical requirements. For example, a worker
is generally more likely to mishandle a load near the
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upper limit of his carrying capacity than he is a
lighter one.
c- Required precision. For example, a worker is much
more likely to make one or more errors in precisely
setting a continuous fine-tuning knob than he is a
discrete position switch with positive detents.
d. Complex response requirements. For example, a manager
faced with a need to justify his plant's performance
to a whole complex of concerned agencies is much more
likely to become involved in communication difficul-
ties than if he has only a single-point responsibility.
e. Ambiguous feedback. For example, an operator is
more likely to miss the need for further process
control actions when there is a significant delay
in feedback of information about the effects of con-
trol measures which he has previously taken.
There are also a number of general factors which can increase the proba-
bility of error on any or all aspects of performance, including:
1. An unfavorable physical environment, including such factors
as extreme temperature, crowded work space, poor lighting,
noise, and wetness or ice.
2. Either an overload (too much work for the time available)
or so little in the way of active work requirements that
attention wanders.
3. Poor motivation or morale on the part of the plant staff.
4.2.3 Assess the Maximum Consequences of Error
Determine the likely worst consequences of each error if it is not detected,
or is detected only after its worst consequences have occurred. Consider
at least the following kinds of consequences:
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1. Time loss.
2. Degraded process control, including possible effects on each
of the parameters identified in Chapter 2.
3. Equipment damage.
4. Wastage of materials and/or purchased services.
5. Personnel injury.
6. Increasing the opportunity for other, possibly more serious,
errors.
4.2.4 Assess the Probabilities of Error Detection
Assessment of the probabilities of error detection should include at least
the following steps:
4.2.4.1 Identify the significant opportunities for detection.
For example, detection may be almost inevitable on the
next operation if an error is made on a setup step which
is essential to performance of the following operation.
4.2.4.2 Identify who may be involved in the detection. For
example, the perpetrator of the error, a fellow worker,
an inspector, the plant manager or other supervisor may
all have an opportunity to detect an error.
4.2.4.3 Estimate the probability of detection at each signifi-
cant opportunity^.
4.2.4.4 Estimate the elapse of time and relevant changes in
system status likely to occur between error event and
detection.
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4.2.5 Assess the Distribution of Consequences
Assessment of the distribution of error consequences should involve at
least the following steps:
4.2.5.1 Cross-compare (for each possible error) the probability,
maximum consequences, and likelihood of detection.
4.2.5.2 Eliminate from further prime consideration those activ-
ities lacking any significant potential for error con-
sequences.
4.2.5.3 Estimate (for the remainder of activities and errors)
the frequency of different kinds and levels of error
consequence.
4.2.6. Assess the Probable Payoff from Job Aids
Assessment of payoff from job aids should include the following steps:
4.2.6.1 Identify the types of aids appropriate to each activ-
ity with potential for significant error (including
too slow performance). The classifications and des-
criptions of job aids in appendixes B and C should be
useful in suggesting possible job aids.
4.2.6.2 Make tentative choices of the preferred type or com-
bination of types of aids.
4.2.6.3 Estimate the impact of proposed aids under conditions
of optimum use.
4.2.6.4 Modify estimates of job aid payoff by estimates of
their probable use. For example, it is typically
the case that the usual operating and maintenance
manuals are irifreauently referred to except by very
inexperienced workers or when unusual circumstances
are encountered.
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4.2.7 Assess Tradeoffs with Job Aids
Consider job aids in conjunction with and as alternatives to other design
features of the operating environment. Principal among the factors to be
traded off against job aids are:
1. Personnel selection. The requirements for job aids become
less stringent as increasingly higher levels of worker
knowledge and skill can be assumed. At least three factors
constrain use of personnel selection as a means of mini-
mizing operational difficulties:
a. With increasingly complex designs for municipal
wastewater treatment plants, even the most out-
standing staffs require assistance if they are
early to achieve full performance potential on
new operations.
b. It is not only costly, it may literally be impos-
sible to recruit the most knowledgeable, skilled,
and experienced personnel.
c. Beyond a certain point, selection of excessively
skilled personnel can have its own negative impact.
Workers who are over-qualified can become bored,
inattentive, prone to absenteeism, a source of
errors, a detrimental influence on the morale of
other workers, and a turnover problem.
2. Training. Personnel who are highly trained on a new set of
operations generally require a lesser set of informational
job performance aids than untrained personnel. However, the
performance of even the most highly trained workers may bene-
fit from job aids, especially where:
a. A great deal of specific, detailed information
is involved.
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b. Standardized written records are desired of the
worker.
c. Tasks are infrequently performed and/or must be
responsive to unusual circumstances.
d. The worker must make relatively complex judgments
according to specified criteria.
3. Human engineering. Design of equipment to facilitate per-
formance of required tasks can substantially lessen the
requirement for separate job performance aids. Indeed, in
a sense, the design of informational job performance aids
is simply an extension of equipment and facility human
engineering. However, cost considerations can lead to
definite limits on the extent to which required job infor-
mation can be built into the equipment and facilities with
which workers interact.
4. Automation. Instrumentation and automatic control are ways
of eliminating many traditional operating tasks. However,-
not only are these means constrained by technical state-of-
the-art, they will commonly increase requirements for:
a. Operator monitoring of machine performance.
b. Maintenance of increasingly complex equipment.
c. Management of a technologically sophisticated
and malfunction-vulnerable system.
4.2.8 Define Job Aid Objectives and Specifications
Summarize the assessment of needs for informational job performance aids
in terms of at least the following areas of tentative conclusions:
1. The activities to be supported with job aids and the
error potential to be reduced thereby.
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2. The types of aids to be used in support of each activity
including an indication of the content and means of
presenting the content.
3. Special features recruired of an aid to meet unusual needs
such as accessibility of visual information without inter-
ruption of a primary task which requires both hands to be
fully occupied.
4. Critical assumptions about other characteristics of the
operating environment required if tentative conclusions
about job aids are to be valid. For example, these assump-
tions might include reference to the particular task analy-
sis documents which define activities and likely errors,
characteristics of workers, and environmental conditions
(such as lighting, humidity) under which aids will be
used.
5. Sources of data that should be drawn up in the construction
of each aid.
4.3 Structure Information Needs by Positions/Jobs
Relate the job aid requirements identified under 4.2 to the position and
job information developed per Chapter 3. This is a preliminary step toward
the effective organization of job aids. If each requirement is translated
into an independent aid, the worker may be hampered by a welter of infor-
mation which will impede rather than enhance his performance. Thus, it
is essential that requirements be translated into an articulated set of
aids which are conveniently available. But, it is all too easy to organ-
ize and cluster aids in ways which are not compatible with the broader
requirements of positions and jobs, even if individual needs for aids are
derived in relatively microscopic detail from task data per Step 4.2. In
order to avoid the twin dangers of disarticulated and wrongly clustered
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aids, the following steps should be followed in structuring information
needs by positions/jobs:
4.3.1 Identify job aids that can satisfy multiple information
needs. These needs can be across activities within tasks,
work positions, or jobs. For example, a basic process
flow diagram might be used both by operators and mainte-
nance workers.
4.3.2 Assure the convenience of each job. Organize plans for
aids such that the set of aids for each defined job
represents an accessible and orderly whole. Avoid having
persons with one job search through information, most of
which is relevant only to other jobs.
4.3.3 Allow for flexibility in the definition of jobs at the
local plant. Each plant is likely to demand some unique
variation in the way duties and work positions are clus-
tered into total jobs. This variation may stem from:
a. Special local circumstances, such as labor
agreements, which constrain work assignments.
b. Optional areas of work assignment where duties
can be shifted across jobs on a day-to-day or
week-to-week basis.
c. Evolution of improved procedures and assign-
ment as a plant and its organization mature.
This means that job aids should be organized primarily
around clusters of tasks (duties, work positions, and
functions) always likely to be performed by a single
worker during any given assignment—even if the cluster
of tasks may be assigned to persons with different job
titles from time to time. Though job aids are primarily
organized around such unitary assignment units, this
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should not be construed to violate 4.3.2, above. Conven-
ient access should be provided to a job aid for all jobs
that may have occasion to use it. For example, there may
be a central file of procedural checklists and/or they
may be posted at the physical work station. Each job may
have its own manual which references the relevant check-
list and indicates its location.
4.4 Sequence Information Needs
The structuring of information needs by positions/jobs (Step 4.3) provides
a first basis for organizing job aids. Further organization of aids can
be achieved by systematic concern for the sequence in which information
is presented. Such concern can be reflected in the following steps:
4.4.1 Determine invariant order.
4.4.2 Determine contingent order.
4.4.3 Determine temporal imperatives.
4.4.4 Determine frequency implications.
4.4.5 Determine criticality implications.
All of these steps depend heavily upon the results of task description and
analysis as described in Chapter 3 and of assessment of the need for in-
formation support (Step 4.2).
4.4.1 Determine Invariant Order
Determine which activity sequences are always to be carried out in the
same order. This will guide the structuring of job aids in a compatible
arrangement. The determination of invariant sequences will depend in sub-
stantial measure upon knowledge of the processes, equipment, and facili-
ties of the plant. For example, a determination of the exact order for
re-assembly of a pump may depend upon rather intimate familiarity with the
design of that particular component.
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Activity sets whose order is not clearly imperative pose an added problem.
Even though it may not, strictly speaking, make any significant difference
to plant performance in what order a set of activities is carried out—it
may be a matter of convenience to have some order specified. It is desir-
able, then, to distinguish:
1. Invariant sequences of activities where the order is
essential.
2. Activity sequences that are probably better described
as invariant, even though the order is essentially arbi-
trary.
3. Activity sets that have to be performed within prescribed
limits, but whose order of performance is at the discre-
tion of the plant manager or individual worker.
4. Contingent sequences, which represent an added set of
considerations as outlined below.
4.4.2 Determine Contingent Order
Contingent sequences of activities impose a special burden upon job aids
in that the requirements for information to guide the order of activity
may equal or be greater than requirements for describing or otherwise
supporting individual activities. This is in contrast to invariant activ-
ity sequences since an indication of order for such sequences can be handled
by such obvious techniques as sequential numbering.
As with invariant orders of activity, the determination of contingent
sequences involves use of substantial knowledge about plant facilities,
processes, and equipment. For example, it takes considerable knowledge
of plant processes and trouble symptom relationships to prescribe a trouble-
shooting procedure by which an operator can diagnose effluent quality
problems through an efficient series of checks, with each subsequent
determination based on the results of his previous reading.
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The most difficult contingent series to identify, delimit, and support
with useful information, however, are those in which the contingent actions
can only be determined on the basis of probabilities rather than on the
basis of deterministic factors such as equipment design. For example, a
plant manager's strategy for purchasing supplies may be based on predictions
about behavior of the market over time. One factor making a determination
of such contingent action series difficult is the freedom the designer has
in specifying the degree of contingent action to be taken. In the pur-
chasing example, it is possible to define relatively invariant procedures
which ignore market dynamics or to define sophisticated algorithms which
seek to minimize costs over time. Similarly, there will typically be
considerable freedom in specifying the rigidity of response in dealing
with factors disruptive to process control.
In determining contingent sequences, particularly where they involve
probability estimates or complex problem solving, it is essential that the
prescribed procedures be defined. Hopefully, this prescription will be
reflected in the task descriptions and analyses covered under Chapter 3.
If any ambiguity remains, however, it must be resolved at this point in
designing job aids.
4.4.3 Time Frame Implications
Certain actions may be constrained not only as to sequence relative to
other actions, but may also have to be performed within some time frame
determined by conditions, events, or other actions. Such temporal require-
ments may also have implications for the availability and design of job
aids which support the relevant action. Review, therefore, task information
against previously identified job aid requirements to determine any addi-
tional requirements which are imposed by time contraints.
4.4.4 Determine Frequency Implications
A great deal of the structuring of job aids will be determined by considera-
tions derived from previous steps. However, frequency considerations may
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still be a factor in determining the final structure of aids. Note, how-
ever,- that the important concern here is not simply a repetition of the
concern for performance frequency in assessing the probability of error
(Step 4.2.2). Rather, the crux of the concern here is with an estimate
of the frequency with which an aid will be used since this may have impli-
cations for the relative accessibility of the aid.
4.4.5 _Determine Oiticality Implications
The assessment of need for information support (Step 4.2) should reflect
substantial concern for the criticality of job aids. However, as a last
step in determining sequence considerations, it is important to review
the evolving structure of aids to assure that the most critical perform-
ance is given appropriate precedence.
4.5 Determine Functions Served by Information
Review job aid analyses evolved to this point, in conjunction with related
job/task data, as a basis for deciding upon functions to be served by
informational job performance aids. Each function is defined by at least
three main characteristics:
1. Purpose.
2. Extent of memory support.
3. Amount of discretion left to the worker.
There are six main purposes to be served by a job aid. They are to:
1. Alert the worker that his action is required and what
aspect of his job responsibility is involved.
2. Sequence the worker's actions, with respect to each other
and with respect to events in his environment.
3. Orient the worker to where (for example, with what components
of the system) his action is required.
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4. Instruct the worker how to carry out his required actions.
5. Inform the worker about standards to be met, cautions to
be observed, exceptions to be made, etc., in carrying out
his work.
6. Exemplify, with pictured and/or descriptive samples of
specific work performances, satisfactory ways of carrying
out instructions.
The extent of memory support can vary from no aid (leaving the worker
on his own to cope with the dynamics of his work environment) to a full
description of the context and performance requirements that would suffice
to support a novice worker. If an informational aid of some kind is pro-
vided, minimum description is aimed at providing the worker with cues
rather than providing full substantive description. Three types of cues
must be considered:
1. Memory cues are aimed at jogging the worker's memory.
For example, a checklist may present only the barest out-
line of work steps, depending upon the worker's memory for
the specifics of procedures to be followed.
2. Highlight cues are aimed at helping the worker to select
(out of a larger informational context) that information
which he feels he needs. For example, sections of an
operating manual may be arranged so as to present general
prescriptions initially with more detailed supportive
information later—somewhat in the form of a classic news
article.
3. Index cues are aimed at helping the worker gain access to
information which will aid his job performance. Subject
indexes, tables of contents, and diagrammatic indicators
of source materials are examples of index cues.
A given job aid element may, of course, support multiple kinds of cuing.
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The amount of discretion left to the worker can vary, at least in theory,
from complete freedom on the part of the worker to total prescription of
his actions.
4.6 Determine Units and Formats for Information Support
4.6.1 Determine Units of Information Support
Structure the content of job aids to:
1. Cover as many work steps as possible, commensurate with
clear and effective presentation of information for each
step.
2. Encourage straightforward series of work steps, handling con-
tingency situations as simply as possible.
3. Minimize the irrelevant information facing the worker during
any given use of the aid. Where the bulk of information
potentially needed by the worker for a given task is rela-
tively large:
a. Cluster the information into units which the worker
can use in sequence and/or at his discretion.
b. Provide cuing aids that will help the worker to
conveniently select only that information which he
needs.
4. Parallel the way in which the worker will normally perform
his job. In particular, this means:
a. Assure easy access to job aid information in the
order of usual performance.
b. Make the job aid units consistent with the start
and end points of work tasks and major duty cycles.
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5. Serve the varied requirements of different work locations,
which include:
a. Keep the size of any one aid commensurate with the
most restrictive conditions under which it is likely
to be used.
b. Allow for easy portability of aids likely to be
used in multiple locations.
c. Minimize the likelihood of conflicting demands
for a given aid by different workers.
4.6.2 Determine Formats for Information Support
Decide on the appropriate format for each independent unit of job aid
information. Recognize that there is an interaction between the media
of presentation and formats of presentation. Principal among the media
which might be considered for the presentation of job aid information are:
1. Audio is essentially limited to narrative job instruc-
tions, although it may be possible (but unlikely) that it
will be cost/effective to provide reference audio signals
that will help the worker to analyze aural cues (such as
sounds of equipment operation) heard on the job. The
main advantages of audio presentation are:
a. Use of an alternative channel of information
input when the worker's visual channel is fully
occupied with tracking signals in his environ-
ment .
b. Convenient pacing of work activities.
2. Video and movie projection permit speeded, slowed, and real-
time presentation of change information such as the lag
characteristics of instruments following different control
manipulations. They can readily be combined with an audio
presentation.
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3. Microform (roll film, microfiche, cartridge or cassette,
aperature card) provides copy which is economical in terms
of cost and storage space. Microform applications can
range from programmed filmstrips with audio support to a
film analog of a document library. Combined, with an -
effective indexing scheme, and even a modest computerized
retrieval system, microform systems can provide the worker
with easy access to a large base of job information.
4. Computer programs can assist workers in data processing and,
through the implementation of formal models, forecasting of
results from contemplated actions. With increasing sophis-
tication of municipal waste treatment plants, it is likely
that computers will be increasingly used in automated process
control. They may well become such an integral part of the
plant environment that it will be difficult to determine if
they are part of the on-line system or used as separate infor-
mational job performance aids.
5. Hard copy (manuals, checklists, drawings) has been overwhelm-
ingly the dominant medium for informational jobs performance
aids. The format considerations presented below have most
immediate reference to hard copy, although they can equally
be applied to video and microform. Some of these format con-
siderations can selectively be applied to audio and computer
program design as well.
In the selection, and later detail design, of formats for each unit of job
aid information, consider at least the following general kinds:
1. Narrative text.
2. Tabular text.
3. Tables.
4. Diagrams.
5. Pictorials,
,&kMj"ji_i-tw i~a->rtMHi U.S. EPA
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6. Formulas and algorithms.
7. Graphs.
Each of these types of format is described below.
Narrative text. In general, minimize the use of open-format narrative.
It may, however, still prove to be the most effective format for some pur-
poses—especially as a stage-setter for the application of more highly
formatted aids. Use cuing devices liberally in such text, including:
1. Frequent paragraphing.
2. Numerous short titles.
3. Underlining, different type, arrows, color, geometric forms,
shaded areas, boxed materials, and other devices to draw the
worker's attention.
4. Concise examples.
Tabular text. As narrative text is increasingly cued and formatted, the
line between it and tabular text becomes tenuous. The distinguishing
characteristic of tabular text is presentation of discrete units of infor-
mation as ordered sets. Well-designed tabular text is much more effective
for presenting job procedures than equally well-written free-narrative
text. Tabular text lends itself to quite abbreviated statements in the
form of checklists.
Fundamental textual units are usually presented as a vertical series, from
top to bottom of the page. If the nature of the actions described by the
text are highly varied from one unit to another, it may be best to leave
the order of presentation within each unit open. More typically, however,
there will be sufficient homogeneity from one action to another that com-
munication will be simplified by following a uniform order for presenting
information within each vertical unit. If the individual vertically
sequenced information units are relatively simple, uniform order of pre-
senting classes of information within each unit will probably provide
sufficient format structure. If the vertically defined information units
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tend to be lengthy or complex, horizontal structuring of text through the
use of designated columns will help to simplify the worker's use of tab-
ular text.
Simple serial procedures most obviously lend themselves to support by
tabular text. However, it is also possible to develop tabular text to
support complex tasks with a large number of contingencies. For example,
fault diagnosis and troubleshooting tend to be the most complex tasks
in plant maintenance. In Figure 17 is presented sample tabular text in
support of a sample fault diagnosis and troubleshooting task. Note the
vertical sequence of information units and horizontal format for each
unit.
Tables. Highly formatted tabular text such as that illustrated in Figure
17 comes very close to being a table with high textual content. Indeed,
the line between the two is arbitrary. Tables are especially used for
the presentation of highly abbreviated, coded, and quantitative informa-
tion. One kind of table having particular relevance to the design of
informational job aids is a decision table, which is intended to assist
the worker in choosing the proper course of action in the face of a large
number of contingent conditions. One of many possible formats for such
a table is illustrated in Figure 18.
Diagrams. Construction blueprints, engineering schematics, installation
diagrams, wiring diagrams, and process flow charts all contribute to the
body of information available for potential use in job performance aids.
Such diagrammatic materials may well be required as part of the plant
documentation regardless of their relevance to job aids. Their availabil-
ity, however, is not sufficient justification for their inclusion in job
aids. They should be used only so far as they are judged to have signifi-
cant potential for enhancing worker performance. Also, diagrammatic
materials prepared for design and construction are not necessarily uni-
tized, at the level of detail, in the format, or associated with the col-
lateral information that would make them most useful as job performance
aids.
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00
Step #
T.ll.l
T.11.2
T.11.3
T.11.4
T.11.5
T.11.6
T.11.7
x — '
Action
Check power lamp K3
Check circuit breaker X7
Depress circuit breaker X7
Manually rotate motor shaft
Replace motor bearings >>>>>>
Check flow rate gauge 112
Turn power off; remove gear
housing; inspect
, »
+^S*^** ^ t~* 1
If this, go tcr>
OFF
OFF
Goes OFF
Bound
LOW
No Damage
L '" "
>-Step #
T.11.2
T.11.3
T.11.4
T.11.5
*T. 11. 3
T.11.7
T.11.8
*-*— »-l
If this, go tcr>-
ON
ON
Stays ON
Free
—
NORMAL
Damage
^-,
- • ^-
>-Step #
T.11.6
T.11.6
T.11.6
T.11.9
—
T.11.45
T.11.20
I • J
Figure 17. Sample Tabular Text to Support Diagnosis and Troubleshooting
-------
Variable
Influent BOD
Effluent BOD
Condition
less than
to
more than
less than
to
more than
Action
Shut valve k, shut valve M
Open valve K, shut valve M
Shut valve K, open valve M
Open valve K, open valve M
*Condition Set
/
/
X
/
/
X
/
/
X
/
/
X
/
/
X
/
/
/
/
X
X
/
/
X
/
/
X
*Since alternative conditions for a given variable
cannot be present simultaneously, the possible
combinations are the geometric sum of all conditions
across variables (in this case, 3x3=9).
Figure 18. Sample Decision Table to Assist Worker
in Choosing Proper Control Action
119
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Diagrams of two types are generally most useful as job aids:
1. Functional flow diagrams which show (either directly or
by reference to other aids):
a. Where the worker intersects with functioning
of the system.
b. The kinds of information about functioning he
should attend to at each point of intersect.
c. How worker activities will impact on system func-
tioning.
d. What the proper procedures are for worker inter-
action with the system at each point of inter-
section .
e. In minimum detail, what the nature of system
continuity is between points of worker intersect
and interaction.
2. Decision diagrams which show, in the form of action trees,
the appropriate course of worker response to contingent
situations. Decision diagrams can take on a variety of
useful formats, one of which is illustrated in Figure 19
using the material from Figure 17 (for fault diagnosis and
troubleshooting) and in Figure 20 the material from Figure
18 (choosing proper control action) in decision diagram
form.
Pictorials. In contrast to diagrams, which typically represent the waste-
water treatment system or component parts in highly symbolic and functional
terms, pictorials represent the system or its components in realistic physi-
cal terms. Pictorials can be a great help to the worker in assigning
proper nomenclature to objects and in locating specific items, but the
following steps should be taken to avoid common mistakes in the design of
pictorials as job aids:
120
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T.ll.l
Check
Power Lamp
K3
T.11.2
Check
Circuit
Breaker X7
T.11.3
Depress
Circuit
Breaker X7
t
X7
^
( \
T.11.4
Manually
Rotate
Motor Shaft
1
T.11.5
Replace
Motor
Bearings
T.11.6
Check Flow
Rate Gauge
I 12
T.11.7
Turn
Power Off;
Remove Gear
Housing;
Inspect
go to
T.11.20
go to
T.11.45
Figure 19. Sample Decision Diagram to Support Diagnosis and Troubleshooting
-------
H
tv>
Check
Influent
BOD
Check
Effluent
BOD
Check
Effluent
BOD
Check
Effluent
BOD
Shut Valve K,
Shut Valve M
Open Valve K,
Shut Valve M
Shut Valve K,
Open Valve M
Open Valve K,
Open Valve M
Figure 20. Sample Decision Diagram to Assist Worker in Choosing Proper Control Action
-------
1. Assure that all pictorials have an explicit function. If
aids are intended exclusively for use in the work environment
(they are not also to be used as off-site training aids),
there is no point to including pictorials of items that can
easily be located directly.
2. Include only necessary detail. One of the principal reasons
for pictorials is to provide simplified representations that
help the worker locate essential items and features. This
purpose will be defeated if pictorials are not highly selec-
tive in the detail presented.
3. Insure sharp focus of critical cues. If photographs are
used, consider touch-up of raw photography to enhance essen-
tial reference cues.
4. Present procedural information on the same frame as the rele-
vant pictorials or explicitly key pictorials to separate
job procedures.
Formulas and algorithms. Mathematical calculations and other data conver-
sions are prone to human error, especially where the worker is under speed
stress. Provide the worker with aid by:
1. Supplying electronic calculating equipment or other devices
which are compatible with data processing demands.
2. Making the form of required data processing operations
consistent with the available aids.
3. Breaking operations into a series of simple steps.
4. Using familiar symbols and operations insofar as possible.
5. Maintaining consistency of symbology and approach across
data processing tasks, insofar as this is possible.
6. Providing especially preformatted worksheets that will
encourage an orderly progression of data processing opera-
tions .
123
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7. Providing a means of cross-checking interim results to
prevent long strings of operations from being in error
due to previous mistakes.
Graphs. Numeric tables have already been pointed out as being one aid
to data processing. Graphs provide an alternative which usually is more
compact but less precise than a table. Of special potential as an aid to
interpreting process control relationships are graphs which permit conver-
sion from one or more variables to another where the relationships are
nonlinear.
4.7 Design and Test A i d s
The design and testing of informational job performance aids includes the
following steps:
4.7.1 Organize and review job aid specifications and task/
performance data.
4.7.2 Define variables to be monitored, controlled.
4.7.3 Define indicators, indications of deviation from stand-
ard control.
4.7.4 Identify possible sources of deviation.
4.7.5 Analyze the dynamics of deviation.
4.7.6 Prepare action strategies.
4.7.7 Draft scheduled aids.
4.7.8 Draft contingency aids.
4.7.9 Review and revise aids.
4.7.10 Format and reproduce aids.
Each of these steps is described below.
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4.7.1 Organize and Review Job Aid Specifications
and Task/Performance Data
Review and exploitation of task data have been both explicit and implicit
throughout the description of Steps 4.1 through 4.6. Here, in the final
design of job aids, task and related plant performance data will be used
continually. Use the insights gained from Steps 4.1 through 4.6 to organize
task and performance data in ways that will make them amenable to use in
this job aid design and testing process.
Results of the analyses described in Steps 4.1 through 4.6 can be recorded
in a variety of ways and degrees of detail. It will usually be desirable,
however, to prepare a brief written summary of conclusions from all reviews
and analyses to guide the design of each aid. The summary for each aid
should include:
1. Reference to backup plant design and performance data, job,
position, and task descriptions.
2. The key characteristics of worker performance to be enhanced
by the aid, and functions served by the aid.
3. The principal sequence and dependency relationships among
actions covered by the aid.
4. Principal sequence and dependency relationships of the sub-
ject aid to other designated aids.
5. Media and formats to be used for the aid.
A sample summary is illustrated in Figure 21.
4.7.2 Define Variables to be Monitored, Controlled
Review relevant plant performance and task descriptions to determine the
system variables to be assured or influenced by worker actions covered by
the aid. If these variables and relationships to worker actions are suf-
ficiently clear to support aid development, move to Step 4.7.3. If the
125
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JOB AID: OG 17 Secondary Tank Shutdown Checklist.
REFERENCE: System Diagram 12, Detail Schematic 1147, Operator
Job Description 7, Position 7.3, Task 7.3.4.
PERFORMANCE ENHANCEMENT: Primarily to assure no steps left out
and proper sequence of steps, not to present detailed instruc-
tions or backup information except by reference to manuals.
Initiation of procedure at option of plant manager.
INTERNAL RELATIONSHIPS: Steps invariant and order important;
order of valve closing especially critical.
RELATIONSHIPS TO OTHER AIDS: Summarizes detailed instructions
0-17.7.3.4 of the operations manual. Manager's handbook
section M-17.7.3.4 describes conditions for electing to
shutdown.
MEDIA AND FORMAT: Plastic-coated checklist with numbered steps,
e.g., "Turn Value 12 full OFF."
Figure 21. Sample Job Aid Summary Description
126
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available descriptions are incomplete or lacking in clarity, revise
and/or supplement them to clarify precisely what about the system is to
be monitored and/or controlled.
4.7.3 Define Indicators, Indications
of Deviation from Standard Control
Review plant performance descriptions, task descriptions, and any supple-
mentary descriptions developed under Step 4.7.2 to determine if the worker
may encounter indications with which he must cope by special contingent
means. Recognize that much hinges on the definition of what are standard
control means and what are special contingent means of system control, and
that the judgments involved in making this distinction are rather subtle.
From the point of view of the job-aid designer, the crucial question is
whether a control procedure requires specialized analyses beyond those
already outlined or can be supported adequately with job-aid designs based
exclusively on analyses prescribed to this point. If further depth of
analysis is required, carry out Steps 4.7.4, 4.7.5, and 4.7.6. If such
analysis is not required, go directly to Steps 4.7.7 and/or 4.7.8—both
of which involve the initial drafting of aids.
Note also that there may be a difference between what is routine to the
job-aid designer and what is routine to the worker. The designer may
choose to break an aid at the point of any contingency and define addi-
tional aids as prescribing special contingent procedures. That is, the
designer has a great deal of latitude in prescribing what are scheduled
or normal procedures and what are special or contingency procedures. Which
aids are defined as scheduled and which are defined as contingency—from the
point of view of the worker—may not entirely parallel the designer's need
or lack of need for special analyses.
Finally, also note that the definition of scheduled or routine aids versus
contingency aids is very much affected by the distribution of responsibil-
ities among workers. For example, an operator may be instructed to call
127
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upon the maintenance department routinely when specified indications are
observed. The job-aid designer may have to carry out no specialized
analyses to determine what conditions should be specified for initiation
of a maintenance call. The maintenance worker's routine for verifying
and amplifying observed malfunction indications may, however, require
specialized analyses in addition to those prescribed to this point—even
though these checkout procedures will be scheduled (in the sense of
always being a first-order of business when receiving a trouble report)
and routine from the point of view of the maintenance worker. If the
maintenance worker is to be further provided with specific instructions
for carrying out troubleshooting procedures, the job-aid designer may have
to carry out additional analyses to support the design of troubleshooting
procedures which are contingent upon the results of checkout routines.
4.7.4 Identify Possible Sources of Deviation
Remember that this step depends upon necessity. That is, it should be
performed as a separate step only if previously developed information does
not support direct design of aids. If additional depth of analysis is
required, begin with an identification of the possible sources of devia-
tion from desired system status or performance. This involves identify-
ing the system components and modes of deviation associated with each
indication for each indicator identified under 4.7.3.
For example, a manager may be faced with a series of periodic reports
(indicators) which show frequent occasions when effluent quality falls
below plant goals in one or more measured parameters (indications) . Pos-
sible sources to be considered might include components and modes or
causes of deviation as suggested in Figure 22.
4.7.5 Analyze the Dynamics of Deviation
Develop a model of the system or that part of the system directly involved
in the tasks of interest. Essentially, this means defining relation-
ships among the relevant components of the system in such a way that it
128
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Components
Inherent Design Defect
Operator Performance
Equipment Defect
Failure Models
Systematic failure when capacity is exceeded.
Influent characteristics which violate design
assumptions .
Monitoring deficiency.
Defective control procedures.
Inadequate periodic maintenance.
Inadequate corrective procedures.
Hidden chronic faults.
Figure 22. Sample Sources of Deviation from
Plant Effluent Quality Goals
129
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becomes possible to identify the information required to distinguish among
possible sources of deviation from desired status or performance. For
example, if the relevant segment of the plant can be represented as the
simple series chain shown in Figure 23, distinguishing among the compon- J
ents (boxes) as a source of deviation from desired performance demands
that a determination be made of whether the process is in-tolerance at
each of the checkpoints (circles) intermediate between known influent and
effluent points (ellipses).
4.7.6 Prepare Action Strategies
Derive, from the appropriate model(s) of plant and processes:
1. A sequence of steps for determining causes of deviation
from desired status or performance goals.
2. A sequence of steps for achieving desired status or
performance.
Determination of the observed indications which should lead to selected
contingent diagnostic checks and corrective action will be the crux of pre-
paring action strategies. That is, it is both critically important and
difficult to judge what the worker should do and not do when faced with
designated information. Most difficult of all will be to balance efforts
to:
1. Minimize worker performance time.
2. Minimize likelihood of worker error,.
3. Keep worker skill requirements within reasonable limits.
4. Minimize plant operating costs.
5. Maximize plant performance.
4.7.7 Draft Scheduled Aids
Determine which aids will support scheduled tasks. Develop a schedule for
such tasks and their supporting aids for each job. Assure that the schedule
130
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Figure 23. Model of Portion of the Plant to Help Analyze
Information Needs for Aids
-------
of tasks is articulated across jobs. Reflect all of the previous analyses
in drafting each scheduled aid. Key scheduled (routine) aids to contingent
aids that will be used in the event specified indications of deviation
from desired status or performance are encountered during and cannot be
dealt with as part of routine tasks.
4.7.8 Draft Contingency Aids
Determine which aids will be required to support tasks that will be ini-
tiated only upon encountering nonroutine circumstances (e.g., a manager
who feels he is not getting full performance potential out of his staff,
an operator faced with a flash flood, a maintenance worker faced with a
major equipment failure of unknown cause). Draft these aids, keying them
to routine aids that may be involved in initiation of or follow-up to
contingent tasks. Also cross-key contingent aids where, depending upon
circumstance, the use of one may lead to another.
4.7.9 Review and Revise Aids
The general concepts and procedures involved in the assessment of all
operational planning, including the preparation of job performance aids,
are described in Chapter 5. No effort is made here to summarize those
concepts and procedures. It should be pointed out here, however, that at
least three steps should be carried out after aids are drafted and before
their final reproduction:
4.7.9.1 Review each aid.
4.7.9.2 Test each aid, by having individuals, similar to those
who will ultimately be using it on the job, actually
perform or simulate performance of the relevant tasks.
4.7.9.3 Revise each aid, if necessary, on the basis of results
from 4.7.9.1 and 4.7.9.2.
Review, test, and revision (as well as the initial design of aids) should
include a concern for the following:
132
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1- Completeness. The set of aids should provide consistent
support across all tasks for each worker.
2. Accuracy. Inaccurate information will cause erroneous job
behavior and/or erode faith in aids.
3. Modiflability. One kind of especially likely inaccruacy
is failure to keep up with evolving plant design, both
planning and post-operational modifications. Provisions
must be made for the update of aids.
4. Clarity. No matter how complete and accurate a job aid
is in a technical sense, it will not have the desired
effect on performance unless it communicates, e.g.:
a. Avoid engineering and technical terms that
might be beyond the educational and experience
level of the intended user.
b. Separate numerical values from verbal text in
most instances; highlight quantitative values
where they must be included in textual material.
c. Present only information which the user may not
know or might forget; use cues rather than narra-
tive text where possible.
d. Present information and data in its most useable
form rather than in a form requiring translation
for its application.
e. Only present variables which are likely to influ-
ence the worker's actions,- avoid a discussion of
variables or issues which are of theoretical value
only.
f. Present all material in size and contrast so as
to be perceived easily by the worker.
133
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5. Accessibility. Package and index aids for easy access to
needed information.
6. Convenience. Consider the conditions under which the aid
is to be used, e.g.:
a. Bind booklets and manuals to permit pages to lie
flat when open.
b. Avoid foldout pages which become unmanageable
where large flat surfaces are not available;
avoid pages which fold out vertically into the
worker's lap.
c. Use work cards or other abbreviated units where
aids must be used without benefit of a conven-
ient working surface.
d. Use extra-sized print and graphics or use audi-
f
tory aids where illumination may be poor.
e. Where information is site specific and needed
\
away from a central work station, mount aids on
equipment or walls.
7- Durability. Provide plastic coating or other protection
where dirt, water, chemicals, or frequent handling may be
a problem.
4.7.10 Format and Reproduce Aids
An essential point to remember about the preparation of final formats and
reproduction of aids is that desirable characteristics may be lost in the
process. For example, wide spacing may be compressed; individual draft
items may be bound together with bindings becoming more restrictive and
permanent. The job aid designer must be alert to all such possible sources
of degradation to job aid utility.
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5. ASSESS OPERATIONAL PLANNING INFORMATION
The need for assessing operational planning information is basically two-
fold. First, there is the need to identify and correct inadequacies of
planning which do not become apparent until assessed in the proper context.
Second, there is a need to receive feedback on operational planning con-
cepts and practices so that future planning activities can build on a
solid foundation of proven planning technology. Thus, assessment provides
a guiding influence throughout operational planning and serves as a check
on the results of planning which, hopefully, will lead to new generalizable
concepts and improved planning technology for the future.
Specific needs for assessment are primarily a function of "newness" and,
hence, the lack of relevant precedents associated with:
1. Data acquisition.
2. Data reduction and analysis.
3. Operational planning concept formulation.
4. Experience of the development team with system analytic and
operational planning activities.
5. Translation of plant information into operational planning
activities and products.
While the level of emphasis placed on assessment can be legitimately
decreased as experience and expertise is gained in required activities of
planning, there will always be a need to make that final evaluation of
the man, as a plant component, and the extent to which his performance is
optimized through the products of planning. The essential attitude one
must adopt is that the input-output characteristics of the man must be
evaluated and optimized along with the machine components of the plant.
An approach to the assessment of operational planning is provided through
the following basic steps, each of which is briefly defined:
135
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5.1 Define assessment objectives and criteria results in the
identification of appropriate goals and criteria for measur-
ing the achievement of operational planning objectives.
5.2 Define data gathering, measurement, and testing procedures
leads to the selection of assessment tools for measuring
the degree of achievement reached for each operational
planning objective.
5.3 Carry out tests results in the application of assessment
tools to provide evaluative data.
5.4 Analyze and interpret results leads to conclusions and
recommendations concerning the optimization of those opera-
tional planning factors which were assessed.
5.5 Translate assessment results into planning action establishes
a framework for applying the results of assessment to the
correction of deficiencies and the overall optimization of
operational planning effectiveness.
5.1 Define Assessment Objectives and Criteria
The principal motive of assessment is, of course, concerned with gaining
feedback on how well operational planning will or has served to maximize
plant operational effectiveness. "How well" immediately implies that
there are objectives to be achieved and that there are measurable criter-
ion values which will permit their assessment.
There are, in fact, two major types of objectives which must be appropri-
ately defined as part of any meaningful assessment. They are:
1 • Operational planning objectives, which are concerned with
some aspect of operational planning.
2. Assessment objectives, which are concerned with goals and
criteria for determining the achievement of operational
planning objectives.
136
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5.1.1 Redefine Operational Planning Objectives
Operational planning objectives were established earlier (Chapter 1) as
one of the initial steps in defining an operational planning program. The
essential characteristics of those objectives were expressed in terms of:
1. The physical form of program outputs.
2. The informational content of program outputs.
3. Dimensions of accuracy and completeness to which the out-
puts must adhere.
The redefinition of planning objectives is aimed at culling forth those
detailed elements which define outputs (informational products, activities,
etc.) to be achieved through the planning program and the expressed quan-
titative/qualitative expectations of the effort (level of completeness,
accuracy, etc.). The resulting enumeration of outputs and expectations
serve two major assessment functions:
1. A check is provided on the clear, concise, and comprehensive
statement of program objectives, providing an opportunity
to further assure program direction and resource allocation.
This check must, of course, be made early in the program if
it is to clarify and enhance efforts of the development team.
2. A consolidated set of program outputs and qualitative/quan-
titative expectations are established as the main framework
for assessment.
5.1.2 Translate Objectives into Operational Criteria
While planning objectives define what is to be accomplished through spe-
cific outputs (thereby defining what is to be assessed), the quality
expectations of these outputs must be translated into a form which will
permit measurement of adequacy. Each output resulting from 5.1.1 must
have a criterion value associated with it to express qualitative and/or
137
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quantitative expectations. If the original statement of objectives did
not provide adequate criteria, or if additional or more specific outputs
have evolved through the process of redefinition, it becomes necessary to
translate expectations into explicit criterion values.
In order to constitute a sufficient basis for judging adequacy, the cri-
terion portion of an objective must define:
1. The variable(s) on which or according to which judgments
are to be made.
2. The point (s) or region(s) on the criterion variable (s) at
which judgments of adequacy will change to judgments of
inadequacy—the term "standard" is applied to such points
and/or regions.
As you will recall from Chapter 1, operational planning objectives will
necessarily vary from one plant to another, from one planning product area
to another, and from one developmental stage to another. In particular,
the stage of development will impact on the level of specificity with
which it is possible to define outputs and criteria. During early stages
of development it is most likely that outputs and criteria will be closely
oriented to planning materials and products. Ultimately, however, the
outputs and criteria must be extended to the specific human behavior
expected of the plant staff through implementation of planning materials
and products.
The objective for staffing information at an early stage of development,
for example, might reasonably be limited to an approximation of the num-
ber of people required in each of whatever job titles are most appropriate;
outputs and criteria would be primarily centered around early task and
job description products. An objective such as this becomes increasingly
more comprehensive and stringent as the final stages of design for a plant
become finalized, while at the same time, a transition toward people and
behavioral outputs takes place. The final objectives in the staffing
example, and the major concern of assessment at the final stage, must be
138
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sufficiently detailed and explicit to foster the hiring and training of a
qualified staff, in the right numbers, prepared to effectively and effi-
ciently perform their jobs when required. Thus, criterion variables must
shift from the earlier physical and content characteristics of planning
products to the results produced by these products in the context of the
plant. Were people with the right qualifications hired? Were members of
the staff adequately trained to perform each and every assigned task? Were
there too many or not enough people1 hired in each job category?
5.1.3 Define Assessment Objectives and Criteria
There are obviously varying levels of effort which should be devoted to
}
the assessment of operational planning objectives. Assessment results in
information which is evaluated in terms of applicable operational criteria,
which are concerned with how adequate individual operational planning
efforts have been. But, these operational judgments must be conditioned
with criteria for the assessment itself—how adequately has it reflected
the true state and how accurate are the expectations which the assess-
ment has established for operational performance. The following classes
of criterion variables must be recognized and their impact appraised as
a factor in defining assessment objectives and criteria.
Validity is the class of criterion variables by which one judges how
assessment results reflect events in the real world. Some significant
aspects of validity are:
1. Relevance—whether assessment results relate to operational
and assessment objectives.
2. Predictiveness—how well assessment results forecast status
at some future time.
3. Bias—the extent to which results are representative of the
population of entities and events to which they manifestly
refer.
139
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4. Sensitivity—ability of the assessment to detect evaluation
dimensions which may not be obvious.
5. Comprehensiveness—extent to which assessment deals with
the full range of significant entities and events.
6. Timeliness^-extent to which assessment results are avail-
able while they are still of use to planning and design
activities.
7. Importance—practical implications of assessment results.
Reliability refers to the degree to which consistent results are obtained
in two or more presumably comparable situations. Sources of unreliability
include:
1. Measuring instruments which do not always record identical
phenomena in an identical way.
2. Respondents or subjects or materials with a seemingly ran-
dom component.
3. Small samples of individuals or events which result in un-
stable estimates of population parameters.
Efficiency is concerned with the extent to which assessment is responsive
to cost and time constraints and accomplishes its useful purpose without
waste.
Figure 24 reflects some broad sample objectives for the five major product
areas of operational planning. Such broad objectives must become more
explicitly detailed with each successive stage of plant design and
development.
140
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Product Area
Operational Planning Objective
Assessment Objective
Delineation of Plant
Performance Charac-
teristics
Analysis of Task and
Job Requirements
Preparation of Man-
agement Information
Preparation of
Operator Informa-
tion
Preparation of Main-
tenance Information
Provide descriptions of plant-
specific characteristics necessary
to support and structure the total
of operational planning activities
and products.
Provide written descriptions of
the types and numbers of person-
nel required for effective func-
tioning of the treatment plant.
Provide information of immediate
and long-term value to management
in properly staffing, training,
and controlling the plant for
cost-effective treatment.
Provide information to plant oper-
ators to guide the control of
treatment with maximum effective-
ness and efficiency.
Provide information to guide the
effectiveness and efficiency of
both preventive and corrective
maintenance of the plant.
Determine the accuracy and ade-
quacy of the data base as a tool
for developing operational plan-
ning materials.
Compare qualitative and quantita-
tive staffing recommendations
with manpower utilization of the
plant after installation is com-
plete .
Compare information provided with
that which is, or was, utilized
and determine inadequacies of
information presented to manage-
ment.
Compare operations information
provided with that which is util-
ized and determine need for
changing performance aid applica-
tions, content, or methods of
presentation.
Compare maintenance information
presented with that which is
utilized; determine the accuracy
of the information and the need
for changing performance aid appli-
cations , content, or methods of
presentation.
Figure 24. Illustrative Assessment Objectives for Some Operational Planning Objectives
-------
5.2 Define Data Gathering, Measurement, and Testing Procedures
This step leads to the selection of appropriate testing and/or other data
collection strategies to reflect if criterion performance for operational
planning objectives is being reached. The measures and data collection
strategies selected must be tailored to the criterion set for each planning
objective.
5.2.1 Analyze Objectives and Principal Dimensions
There are three principal dimensions which serve to characterize the many
possible approaches to collecting assessment data. The analysis of assess-
ment objectives in terms of these dimensions will assist in setting the
stage for a viable assessment strategy. The three dimensions, in brief,
are:
1. static-dynamic. On the relatively static end of the scale
lie retrospection, expert opinion, paper-and-pencil tests,
and utilization of facts in hand or derivable from informa-
tion already available. On the dynamic end of the scale lie
the manipulation of plant components under anticipated con-
ditions of operation and the collection of findings of inter-
est through the systematic observation of plant performance.
An intermediate alternative is simulation of some plant
components and functions according to principles known,
or assumed, to underlie the performance of interest."
2. Experiment-demonstrate. Assessment may vary from carefully
designed and closely controlled experimentation to open-ended
loosely controlled demonstration. The difference in orien-
tation is largely dependent on the purpose. Experimentation
is appropriate for selecting, refining, or modifying a par-
ticular aspect of operational planning. Demonstration is
suitable for showing that operational planning designs or
products suffice for specified situations.
142
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3. Intensive-comprehensive. There are practical limits on the
amount of time and/or effort which can or should be allocated
to the accomplishment of a given assessment objective. Strike
a balance between an intensive narrow look and a less intense
but more comprehensive look across all aspects of objectives.
5.2.2 Evaluate Alternative Approaches
The acquisition of assessment data may draw upon any one, or a combina-
tion of many, of the available collection techniques. The following data
collection approaches, each of which is described in terms of positive
and negative attributes, appear relevant to treatment plant contexts and
will serve as a starting point for the selection of a suitable approach
to assessment.
Discussion and Interview. A principal means for gathering a broad source
of assessment data is through carefully recorded discussions and inter-
views with plant personnel to clarify the effectiveness of the operational
planning effort in reducing operational problems, particularly those prob-
lems which were, or should have been, included in operational planning
objectives. Note all problems not attacked in operational planning so
that they may be included in future planning activities.
It is good practice to have a set of carefully thought-out questions to
structure the interview even though it is quite fruitful to encourage
interviews to go beyond the scope of specific questions.
The most comparable form of information is obtained through use of multiple
choice or rating-type questions. It is generally undesirable to place
exclusive, or even major, reliance on close-ended questions. Extracting
insight from knowledgeable persons (particularly those with experience at
plants with and without significant operational planning) can be much more
rewarding than a scientific survey.
Direct Operating Data. The very nature of wastewater treatment dictates
that large amounts of data will, or should, be collected to reflect the
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operational readiness, loading, level of treatment provided, and other
relevant aspects of the operating plant along a time dimension. Many of
these measures are automatically monitored and recorded on a continuing
basis while others are dependent on human observation and perception.
In any case, there is a substantial number of data collection means
available which—because the data are a routine part of equipment status,
control, or cost information—can be an inexpensive and important part of
evaluating the achievement of operational planning objectives.
Extreme caution is the byword for accepting data from another operating
plant for comparison with the plant of concern when little is known about
the other plant. "Pencil titration" is a trick that is probably more
prevalent than one would like to believe. Make sure that instrumented
data collection is carefully calibrated and maintained and that laboratory
tests are validly performed. Bad data is frequently worse than none at
all.
Incident Reporting. Factual information is best obtained from specific
identified incidents or events pertaining to treatment management, opera-
tions, and maintenance. Asking individuals to discuss their impressions
of, or reactions to, reported operational problems is also useful. If
incident reporting covers a broad range of operational characteristics,
a relatively large number of incidents is required to provide comprehen-
sive coverage of the situation. This would mean that discussion with many
individuals is necessary since most individuals can only reliably report
a handful of incidents on a given topic. Incident reporting is best com-
bined with other techniques because of the limitations on the number of
individuals available in most wastewater treatment applications.
Observation of Operations. Direct observation of the operational setting
provides a convenient means for verifying verbal and written treatment
information and filling in information gaps. It is often desirable, for
at least the purposes of orientation, to observe operations in an unguided
way. For recurrent or prolonged periods of observation it becomes
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necessary to establish specific purposes, sampling procedures, and routines
to prevent gross inefficiencies.
Survey or Questionnaire. Surveys and questionnaires generally appear to
be an easy way to collect a lot of data cheaply and quickly. There are,
however, a number of factors which serve to limit the appearent usefulness
and advantages of this form of data collection. To be carefully designed,
they take a long time to prepare; they should be pretested with a small
representative sample; the time of respondents must be counted as part of
the cost; there are usually a significant proportion of nonrespondents;
and busy design personnel and plant staffs take a dim view of surveys
unless their purpose is immediately relevant and important. In general,
the use of surveys should be highly selective and severely limited.
Document Review. Basic treatment plant design and operating information
is often available and can be used for drawing rough comparisons between
the subject plant and other plants of similar design and size. As an
assessment tool for evaluating operational plans, however, care must be
exercised with respect to extrapolation of data when plant loading, treat-
ment objectives, criteria, and design configuration do not match the
subject plant. It is anticipated that operational planning information
will become an increasingly valuable part of wastewater treatment plant
documentation and that its contribution as an assessment tool will like-
wise increase.
5.2.3 Match Objectives to Best Approaches
From the alternatives outlined in 5.2.2, it is likely that one or two
approaches will appear to have clear advantages over all others with
respect to each assessment objective. It is also probable that some number
of objectives is amenable to the same approach and hold potential for
being carried out through a singular and coordinated effort that will sat-
isfy each objective.
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Match each objective with its most favorable data collection approach,
compromising only where increased efficiency largely offsets any disad-
vantages which might accrue.
5.3 Carry Out Tests
This step centers around the implementation of the data gathering strate-
gies formulated in the previous step. This step should be one of routine
procedure if the proper attention was devoted to defining the previous
step. There are, however, a number of important substeps which will help
ensure efficient and effective data gathering.
5.3.1 Define a Testing Plan
A guide or blueprint is necessary to inform those who will be involved or
concerned with assessment tasks. The plan should cover at least the pur-
pose, objectives, test methods (procedures, criterion variables, measures,
data analysis, test instruments, etc.), facility requirements, report
intentions, and possible benefits to be derived through assessment. Every
assessment effort will certainly not require a fully documented plan, but
every plan should be based on a consideration of the above factors. Assign-
ments and responsibilities for the collection of data must, of course, be
a part of the plan, and it is through the plan that an efficient and
effective data collection effort is directed.
5.3.2 Define Probable Contingencies
Contingencies almost invariably arise and cause the conditions for gather-
ing assessment data to differ from those that were assumed in the plan.
It is necessary to react to these contingencies without compromise to the
entire effort. Unfortunately, operational (field) settings which normally
yield the most realistic conditions for assessment also present the great-
est risk of compromise since establishing and maintaining necessary controls
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is most difficult under these conditions. For this reason, in particular,
it is desirable to try out data collection procedures and provide specific
practice in anticipation of the test and data collection effort, even when
trained and experienced personnel are involved in the assessment effort,
5.3.3 Implement Pretesting
The tryout of planning information on a small scale is essential to over-
all accuracy and utility. Likewise, the assessment process itself benefits
from pretesting of data collection strategies. While the ideal tryout
situation would involve a representative sample of the intended population,
a great deal can be learned about the adequacy of the assessment plan with
tryouts using in-house personnel or other members of the design or devel-
opment team.
5.4 Analyze and Interpret Results
The design for analysis and interpretation of assessment information is
an inherent part of assessment planning. Steps 5.1 through 5.3 should
lead to formulation and implementation of an assessment approach which
will enable the treatment of results in such a way as to permit an ade-
quate test of the criterion set for each operational planning objective.
This step involves execution of a prearranged plan and is not a process
of deciding what to do with data after they have been collected. No
amount of data juggling can compensate for a faulty assessment approach.
The following substeps will assist with carrying out an orderly data analy-
sis and interpretation effort.
5.4.1 Reduce Data to Manipitiable Forms
A difficult aspect of assessment is that many of the data will have sig-
nificant utility only at the time they are collected. Other data are of
recurrent use across a long time span and variety of purposes. Deciding
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ahead of time which data will and will not be of continuing value is diffi-
cult if not impossible. It is, therefore, important from the earliest
stages of assessment to hammer incoming data into a compact, consistent,
manipulable form.
5_.4.2 Implement a Coding and Classification System
The principal way of reducing incoming data to manipulable form is to
categorize incoming data and code them on a real-time basis. Even roughly
preceded data are more useful than raw data that "someone should get around
to doing something with sometime." Early and informed attention to rough
coding and classification procedures will have a beneficial impact through-
out assessment of the evolving treatment plant.
5.4.3 Draw Upon Inferential Techniques
Even after the mechanics of processing data are established, interpretation
of assessment data still remains. Mathematical or statistical models sel-
dom apply to the kinds of data generally available. As an ''operational
planner," you are in essence a creative artist and decision maker faced
with a great deal of ambiguity and uncertainty. Careful use of the best
obtainable data prevents many false starts and erroneous conclusions. In
the final analysis, however, data only provide a platform from which you
can spring to the broad inferential leaps required to accomplish effective
operational plans.
5.5 Translate Assessment Results into Planning Action
The significant contributions of assessment to operational planning can
only be realized if the results are translated into activities directed to
optimization of the planning process, the products generated through the
planning process, and the utility of the products with respect to achieving
plant cost-effectiveness. That is, assessment is directed toward determing
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how closely actual performance approaches the most advantageous region of
performance for the plant. Where disparities occur, there is need for
planning actions to bring actual and desirable performance into alignment.
5.5.1 Apply Cost-Effectiveness to Planning Actions
Concern with optimization actions will occur at two levels. First, there
is the matter of optimizing input/output objectives and requirements as
well as plant performance characteristics in relation to the overall pol-
lution control efforts of the nation. Second, there is the matter of
optimizing operational planning characteristics to meet specific plant
objectives. At both levels, however, resolution is acheived through the
application of cost-effectiveness models for comparing the alternative
objectives or operational planning approaches and selecting that alterna-
tive which will most nearly satisfy pre-established criteria. The con-
structive use of assessment results is, therefore, largely dependent upon
one's ability to progressively optimize that which was assessed.
5.5.2 Document Results and Planning Actions
Much of the potential benefit from assessment can be lost if the results
and intended planning actions produced by assessment are not documented.
Regardless of the formality or informality of the documentation, there must
be at least some manner of recording and communicating assessment results
of significance and any proposed actions for further enhancing operational
planning. Documentation must be sufficient to serve as a plan for carry-
ing out planning actions and as a historical reference to guide additional
iterations of the operational planning process at the specific plant or
permit generalization to other treatment plants.
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OVERVIEW OF APPENDIXES
The four appendixes which follow are in support of general principles and
procedures provided in the main body of this Guide.
Appendix A--Job Description Format and
Development Recommendations
This Appendix provides specific job description format recommendations and
development procedures in support of the ta.sk and job description guidance
provided in Chapter 3.
Appendix B--C1assification and Description
of Informational Job Aids for Managers
The general nature of planning information appropriate to plant management
personnel is briefly described, and suggestions a,re made for presenting
information in the form of job aids. The development of job aids is not
considered as part of the appendix; considerable interaction will be
required between Chapter 4 (Prepare Job Aids) and the material presented.
Appendix (^--Classification and Description
of Informational Job Aids for Operators
The nature of planning information appropriate to plant operations per-
sonnel is provided and suggestions made for the presentation of each
information type through various job aids. Again, close linkages between
the information presented and Chapter 4 are required.
Appendix D--C1assification and Description of
Informational Job Aids for Maintenance Personnel
Types of operational planning information and related practical job aids
are presented for plant maintenance personnel. As with the previous two
appendixes, Chapter 4 provides the specific procedural guidance for
development of each information type into practical job aids.
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APPENDIX A
JOB DESCRIPTION FORMAT AND DEVELOPMENT RECOMMENDATIONS
The essential components of job description were outlined as part of
Chapter 3. This appendix, patterned after the Department of Labor's
Dictionary of Occupational Titles (DOT), is intended to support the devel-
opment of uniform, accurate, and comprehensive job descriptions for use
in operational planning activities for wastewater treatment.
Assign Job Title
A job title is the name by which an occupation is commonly known. The
extent of common usage determines the wording and acceptance of the job
title for identifying an occupation. Other names by which an occupation
is known in various parts of the country or in specific employment situa-
tions are known as alternate titles. Complete identification of an occu-
pation must include both the accepted job title (those listed in the DOT)
and alternate titles which are found to exist. The use of an alternate
title by itself is not an acceptable method for identifying an occupation;
such use leads to confusion.
Invert or Modify Job Titles
Titles of jobs in a specific craft or industry should be inverted or modi-
fied to permit formation of an alphabetic guide, thus keeping the related
jobs clustered together. Examples of inverted job titles are: Carpenter,
Maintenance; and Carpenter, Rough, Examples of job titles modified by rank
would be: Carpenter Foreman, Carpenter Apprentice, and Carpenter Helper.
Job titles to which arbitrary modifiers have been added to distinguish one
job from the other are: Carpenter, Bridge; and Carpenter, Wooden Tank
Erecting. Again, the use of accepted job titles is mandatory, but the
inclusion of alternate titles with appropriate modifiers is encouraged.
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As_sign Six-Digit Occupation Code
A six-digit code number must accompany each occupational definition. The
purposes of this code are to (1) provide a method for grouping jobs with
the same basic occupation or worker trait characteristics, and thus aid in
discerning various occupational relationships; and (2) provide a standard
method for classifying the abilities, vocational experiences, and poten-
tials of workers. The first three digits of the code indicate specific
occupational categories, divisions, and groups. The second three digits
of the code express worker relationships to data, people, and things.
Assign Occupation Category Code
The first digit of the code represents nine occupational categories. All
occupations can be conveniently grouped into one of these broad occupa-
tional categories.
Professional, technical, and managerial occupations
2 Clerical and sales occupations
3 Service occupations
4 Farming, fishery, forestry, and related occupations
5 Processing occupations
6 Machine trade occupations
7 Bench work occupations
8 Structural work occupations
9 Miscellaneous occupations
Assign Division and Group Code
Through addition of the second digit of the DOT code, 84 two-digit divisions
of the nine broad occupational categories are represented. The 84 divi-
sions are, in turn, subdivided into 603 distinctive three-digit occupational
groups represented by the third digit of the code.
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Assign Functional Relationship Code
The fourth, fifth, and sixth digits of the code, which fall to the right
of a decimal point, represent relationships specific to data (fourth
digit), people (fifth digit), and things (sixth digit). Each coded digit
permits the expression of eight levels of complexity, in the form of a
hierarchy, such that each successive function can include the simpler ones
and exclude the more complex functions. The premise upon which the code
is based is that every job requires the worker to function in relation to
data, people, and things in significant but varying degrees. The func-
tional hierarchies for the last three digits follow. Each level of the
functional hierarchies is defined in the DOT.
Data (forth digit) People (fifth digit) Things (sixth digit)
0 Synthesizing
1 Coordinating
2 Analyzing
3 Compiling
4 Computing
5 Copying
6 Comparing
7 ) No significant
8 J relationship
0 Mentoring 0
1 Negotiating 1
2 Instructing 2
3 Supervising 3
4 Diverting 4
5 Persuading 5
6 Speaking-Signaling 6
7 Serving 7
8 No significant 8
relationship
Setting-Up
Precision Working
Operating-Controlling
Driving-Operating
Manipulating
Tending
Feeding-Offbearing
Handling
No significant
relationship
As much care as possible should be exercised to insure that the six-digit
code accurately describes the group arrangement and worker traits arrange-
ment for each occupational definition input to the Manpower Planning Pro-
gram. Each occupation must be carefully assessed, particularly with
respect to the data-people-things hierarchies, to identify the performance
requirements of the job. Task description materials should be the basis
for developing the six-digit code.
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Prepare Verbal Descriptions
A brief verbal description is a required part of the occupational defini-
tion. The purpose of the verbal description is to identify what gets done,
how it gets done, and why it gets done. Additionally, the verbal descrip-
tion may provide, indicate, or imply other information such as functions
performed by the worker, significant aptitudes, interests, temperaments,
and critical physical demands required by the job.
Although the verbal description should be as short as possible, the guid-
ing principle in description development is that the final product relates
a concise and concrete occupational picture which will also convey some
indication of the level of complexity involved. The verbal description
should be prepared from factual data concerned with what, how, and why
the job is performed; task description materials are the best source of
such data.
Define Worker Trait Profile
Worker traits are those abilities, personal traits, and experience charac-
teristics required of a worker in order for him to achieve an average level
of success in performing his job responsibilities.
Six distinct components are used to project a profile of the worker traits
required by an occupation. These worker trait components are:
1- Training time. The amount of general educational develop-
ment and specific vocational preparation a worker must
normally have to qualify for the job.
2. Aptitudes. The specific capacities and abilities required
in order to learn or perform the tasks and duties of the
job.
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3. Interests. The preferences for certain types of work
activities and experiences considered necessary for job
success.
4. Temperaments. The types of occupational situations to
which a worker must adjust.
5. Physical demands. The physical activities required of
a worker in the job situation.
6. Working conditions. The physical environment and sur-
roundings associated with the job.
While it is true that significant worker trait requirements are reflected
in the verbal description of the job, either explicitly or through impli-
cation, the worker trait profile is meant to provide a more definitive and
comprehensive source of worker trait information. The worker trait profile
provides a numeric scale which reflects the range of required traits and/or
levels of traits for each of the components. Alphabetic and numeric codes
are used to identify the ranges and levels for the profile components, thus
saving space and facilitating the comparison of traits across different
occupations. The following paragraphs discuss in greater detail the worker
trait components.
Define Training Time
The training time component consists of defined levels of training in the
areas of General Educational Development (GED) and Specific Vocational
Preparation (SVP).
General Educational Development refers to those aspects of education
(formal and informal) which contribute to a worker's (a) reasoning devel-
opment and ability to follow job instructions, and (b) acquisition of
"tool" knowledges such as language and mathematical skills. GED describes
education of a general type which does not relate directly to recognized
occupational objectives. Such education is ordinarily obtained through
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elementary schools, high schools, or college; it is in contrast to school-
ing directed primarily toward a specific occupation.
A numeric code is used to identify the six levels of educational develop-
ment defined in the DOT, with "1" representing the lowest level, and "6"
representing the highest level of development. The lowest level of devel-
opment is exemplified by "Applying common-sense understanding to carry
out simple one- or two-step instructions," and the opposite end of the
scale by "Applying principles of logical or scientific thinking to a wide
range of intellectual and practical problems." The complete definitions
will not be presented in this manual since they are quite lengthy; Volume
II of the DOT may be consulted for complete definitions of each level of
GED.
Specific Vocational Preparation is defined as training required to learn
the techniques, acquire the information, and develop the mental and physi-
cal skills required for average performance in a specific job-worker situa-
tion. It includes training given through any of the following modes of
instruction: vocational education, apprentice training, in-plant training,
on-the-job training, and essential experience acquired on other jobs. The
appropriate amount of SVP for a job is reflected through a numeric code;
"1" is the lowest level and corresponds to "short demonstration only,"
while "9" is the highest level and corresponds to "over 10 years" of SVP.
A complete listing of the definitions is not presented in this manual;
Volume II of the DOT may be consulted for complete information on the nine
levels of SVP.
It is sometimes necessary to show a range of Specific Vocational Prepara-
tion since requirements vary. The normal range can be shown by listing
both the high and low levels which bound the interval.
Define Aptitudes
Aptitudes are defined as specific capabilities and abilities required of
a person in order to learn or adequately perform a task or job. There are
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11 distinct aptitude areas to be considered as part of the worker trait
profile. The areas, and the letter symbol code for identifying each, are:
G Intelligence
V Verbal
N Numerical
S Spatial
P Form Perception
Q Clerical Perception
K Motor Coordination
F Finger Dexterity
M Manual Dexterity
E Eye-Hand-Foot Coordination
C Color Discrimination
A numeric code is used to indicate how much, or what level, of aptitude
is required for satisfactory (average) performance of job tasks and duties.
The average requirements, rather than maximum or minimum, should be cited.
The level of aptitude appropriate for each area is designated by using the
following scale, which is expressed in terms of equivalent amounts of apti-
tude possessed by segments of the general working population.
Level 1. The top ten percent of the population.
Level 2. The highest third, exclusive of the top ten
percent of the population.
Level 3. The middle third of the population.
Level 4. The lowest third, exclusive of the bottom ten
percent of the population.
Level 5. The lowest ten percent of the population.
This numeric scale is applied to each aptitude area. The resulting expres-
sions should be presented in tabular form as shown below for a hypothetical
case.
Apt:
* *
G V N
111
222
S P Q
223
3 3
K F M EC
444 55
eSignificant Aptitude
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As shown in the above example, more than one level can be used for an apti-
tude area when job circumstances dictate a rather broad range of aptitude.
The range must never exceed two levels, and it is desirable to discriminate
to a single level.
Significant aptitudes should be identified as such by the use of bold face
type for the area code or through the use of an asterisk above the code.
Significant aptitudes are those considered essential for average success-
ful job performance.
Define Interests
Interests are defined as the preferences an individual may have for certain
types of work activities or experiences. As part of the worker traits pro-
file, interests are expressed in terms of positive preferences for one
factor of a mutually exclusive pair of factors which define certain activ-
ities. Five pairs of factors are provided so that a strong preference for
one factor implies rejection of the other factor of the pair. Examples of
factor pairs are:
Code 1. Situations involving
a preference for
activities dealing
with things and
objects.
vs. Code 6. Situations involving
a preference for
activities concerned
with people and the
communication of
ideas.
The expression of interests in the worker traits profile is accomplished
by listing the numeral designations for the most applicable activity fac-
tors. It is unlikely that the activities of most jobs will result in
strong associations with more than two or three interest factors. It is
not desirable to "force" a factor from each of the five pairs into the
interest portion of the profile; attention should be given to those which
are consistent with the tasks and general requirements of the job.
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Define Temperaments^
Temperament refers to the nature or disposition characteristic of personnel
in specific occupational situations who satisfactorily adjust to the per-
formance demands of the job. For the purpose of the worker traits profile
12 rather broad situational contexts have been developed to represent the
entire domain of occupational situations. A number or letter is used to
represent any of the 12 defined situations in the profile. Examples of
the situation definitions to be used are:
Code 1. Situations involving a variety of duties often
characterized by frequent change.
Code 4. Situations involving the direction, control, and
planning of an entire activity or the activities of
others.
All activities of the job which closely match defined situations should
be represented in the worker traits profile by entering the appropriate
number or letter code. There will generally be more than one situation
which applies, but rarely will there be more than five or six.
Define Physical Demands
Physical demands are defined as those physical requirements of the job
and physical capacities (specific physical traits) of personnel necessary
to meet the job requirements. In all cases, the worker must have physical
capacities equal to or in excess of the physical demands of the job.
There are six major physical demand factors which will be used to define
the physical capacities of workers in the traits profile. Only those
factors which are essential to job activities should be entered in the
physical demands portion of the worker traits profile. A close compari-
son must be made between the task requirements of the job, as reflected
in the task description materials, job data banks of environmental protec-
tion agencies, and DOT definitions before entering the profile information.
These factors are:
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1. Lifting, carrying, pushing, and/or pulling (strength). This
factor is expressed in the profile by entering the letter
code for those strength definitions which typify normal work
activities for the job. The five strength categories, which
are completely defined in the DOT, are:
S Sedentary Work
L Light Work
M Medium Work
H Heavy Work
V Very Hard Work
2. Climbing and/or balancing. The number "2" is entered if
any part of the definition for this factor is an element
of job activities.
3. Stooping, kneeling, crouching, and/or crawling. The num-
ber "3" is entered if any job activities match the defini-
tion for this physical demand factor.
4. Reaching, handling,_ fingering, and/or feeling. The number
"4" is entered if the definition for this factor applies
to job activities.
5. Talking and/or hearing. The number "5" is entered if the
definition for this factor applies.
6. Seeing. The number "6" is entered if the definition for
this factor corresponds to a required activity of the job.
Defi ne World ng Condi ti cms
Working conditions are defined as the physical surroundings of a worker
in a specific job situation. Working conditions are meant to describe
the physical environment factors which a worker must be physically and
mentally prepared to withstand as a normal part of the job.
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There are seven broad factors of physical surrounding which must be con-
sidered in defining the working conditions applicable to a job. These
factors are:
Code 1. Inside, outside, or both.
Code 2. Extremes of cold plus temperature change.
Code 3. Extremes of heat plus temperature change.
Code 4. Wetness and humidity.
Code 5. Noise and vibration.
Code 6. Hazards.
Code 7. Fumes, odors, toxic conditions, dust, and poor ventilation.
Coded entries to the working conditions portion of the worker traits pro-
file should only be made for those instances where job activities meet or
exceed the criteria defined in Volume II of the DOT.
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APPENDIX B
CLASSIFICATION AND DESCRIPTION OF INFORMATIONAL JOB AIDS FOR MANAGERS
The operational planning effort should result in certain information
designed to assist managers with their functional role in the treatment
plant. This information, tailored to the characteristics and operational
setting of the individual plant, provides managers with the necessary
tools and resource materials to smoothly and effectively phase new or mod-
ified treatment plants into operation. Longer-range utility of the infor-
mation provided to management is derived through their ability to adapt
and modify the initial framework to meet future requirements.
Operational planning products for managers are described in terms of appro-
priate job aids and job aid content. Development of the job aids should
be carried out through use of the principles and procedures provided in
Chapter 4. The following classification of essential management job aids
is provided in this appendix:
1. Planning aids—outline important areas of personnel and
training which must be attended to prior to operational
status of a plant.
2. Aids to external relations—provide management with guide-
lines and suggestions for interacting with other agencies
and the public.
3. Scheduling aids—provide management with milestone data to
assist with effective planning of the transition to opera-
tional status.
4. Budgeting aids—assist management with the preparation of
meaningful funding and budgeting information.
5. Aids to operational management—provide a basis from which
managers can assess performance of the plant.
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6. Aids to Maintenance management—provide a basis from which
management can evaluate maintenance aspects of the plant.
7. Aids to management of purchased services—provide guidance
for decision-making with respect to in-house versus contracted
plant services.
8. Aids to personnel management—provide guidance for develop-
ing and maintaining a properly motivated work force.
9- Aids to data management—provide guidance for establishing
and maintaining a data system to assist with management
decisions.
Provide Planning Aids
Provide Training Specifications
Provide management with training specifications to guide the professional
and technical development of required plant personnel. The specifications
should provide a recommended curriculum of instruction for all jobs having
task requirements beyond the normal repertoire of skill and knowledge for
the intended population of new-hire or other job enrollees. The recommended
curriculum for each job title should be expressed in terms of:
1. Subject or topic areas.
2. Training time (hours) estimate.
3. Training aids and other required materials.
4. Training objectives.
It is important that the training objectives properly define the perform-
ance parameters the trainee is to meet in order to fulfill job responsi-
bilities. For most jobs, the inexperienced employee is not expected to
perform assigned tasks at the same proficiency level as would be expected
from experienced workers. In other cases, particularly with respect to
hazardous or critical tasks, the trainee must achieve a level of skill
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equal to or surpassing job requirements to insure initial task success.
The guiding principle for training objectives should be that they inform
management and subsequent training developers what must be expected of
the trainee in order to "pass" each portion of the training curriculum.
Curriculum and training specifications, which may be available for certain
treatment plant jobs through the Division of Manpower and Training of
EPA, can serve as the heart of plant-specific training and/or as models
for other jobs. Figure 25 reflects a sample format for curriculum and
training specifications.
Recommend Training Sources
Provide management with recommendations concerning how and where required
training can be best accomplished, particularly with respect to formal
classroom training in specific pollution control subject matter. Regularly
scheduled sources for formal training are relatively limited in terms of
the curriculums offered, the proximity of training institutions to plant
locations, and the time phasing of enrollment opportunities and courses
of instruction offered. A general search for sources of job training
should include the following:
1. Contact the Training Division of EPA as early as possible
to determine the dates, locations, course outlines, and
other pertinent information about short courses offered
through the auspices of EPA and to determine their recom-
mendations for your specific training needs.
2. Contact nearby vocational/technical schools, colleges, and
universities to determine what courses they offer that
might fit specific training needs for the subject plant.
3. Contact equipment manufacturers and vendors of installed
equipment to determine if they offer formal training in
the operation and maintenance of their equipment, time
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Curriculum and Training Specifications for (Job Title) :_
system class: Wastewater Treatment, Municipal
Laboratory Assistant
Generic system Type: Primary Treatment (Digestion and Sludge Beds)
CURRICULUM
TRAINING AIDS AND MATERIALS
TRAINING OBJECTIVES
Laboratory/Plant Safety
(6 hours)
/ Chemical Handling
•J Treatment of Chemical
Burns
\/ Basic First Aid
•J Laboratory Fire
Fighting
J Etc.
Plant Laboratory Facilities
MSA First Aid Kit #
First Aid Handbook, Amer. Red
Cross; 19— Edition, Chap 1, 4,
11, and 12
WPCF Manual #1, Safety in Waste
Water Works; WPCF, 19— Chaps.
4 & 5 unless better emphasis on
laboratory work can be found
elsewhere
Chart showing fire and emergency
evacuation plan for the plant; a
floorplan with exit routes will
have to be developed
5 pound CO and dry chemical fire
extinguishers
Etc.
Trainee must be able to:
>/ Explain and demonstrate proper way
to mix acids and alkalies.
•J Describe procedures and point out
materials for treating a chemical
burn.
^ Describe symptoms for chlorine poi-
soning and immediate treatment to
be provided.
v/ Point out location of fire extin-
guishers in the plant.
»/ Describe procedure for extinguish-
ing chemical, electrical, and other
fires using either dry chemical or
CO extinguishers.
/ Describe appropriate first aid
technique for injuries listed in
Appendix II of First Aid Handbook.
/ Etc.
Correspondence Course in
Water Analysis Techniques
(30 hours over a 6-week
period)
J Tests for BOD
/ Tests for COD
/ Tests of suspended
solids
T/ Etc.
EPA Correspondence Course, Series
IV, Booklets 1 thru 6
Plant Laboratory Facility
Handbook of Chemistry and Physics,
any of the reputable publishers
Etc.
/ Set up and conduct required tests
to prescribed scientific standards.
/ Prepare standard data sheets to
show results of tests conducted.
• Etc.
Water Sampling Techniques
Etc.
Etc.
v/ Etc.
Figure 25. Sample Format for Curriculum and Training Specifications
-------
requirements for such training, and the nature of any
costs involved.
4. Contact state and local regulatory agencies for courses
they may offer with respect to the training and licensing
of operators, laboratory personnel, and maintenance per-
sonnel.
Recommend Training Aids and Materials
Provide management with a list of specific training aids and materials
useful for the training environment. Recommended training aids and mate-
rials should accompany each course of instruction in the recommended cur-
riculum to enhance and support the instruction. Training aids and mate-
rials are characterized by:
1. Text books, instruction manuals and reference manuals.
2. Films, slides, flip charts, and other graphic media.
3. Models and simulations of the plant or its components.
4. Self-instructional texts.
5. Operations and maintenance manuals.
6. Operational system or plant components and facility
used for training purposes.
Consider an Interactive Training Proposal
A proposal might be made to management for the utilization of plant design
personnel to teach and/or work closely with other instructor staffs during
the initial training period. Such an arrangement will help ensure the
specificity and accuracy of training for the subject plant.
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Suggest a Training and Reference Library
Texts, reference manuals, and other materials deemed appropriate to imme-
diate and long-range training should be identified and presented to manage-
ment so that an in-house library may be established. Other elements of
the library will, of course, be operations and maintenance manuals, plant
design information, and other information of long-term value.
There are, of course, many materials directed to the management, operations,
and maintenance activities of specific types and configurations of plants.
Be selective, limiting training and reference materials to those which
are highly relevant to the specific plant, the nature of training to be
carried out, and the anticipated needs of the plant staff.
Examples of training and reference materials which might be appropriate
are:
1. Manual of Treatment Processes, Water Quality Management
Series, Vol. I, Eckenfelder, Wesley W. (Ed.).
2. standard Methods for the Examination of Water and Waste-
water. Available from the American Public Health Asso-
ciation, American Water Works Association, or the Water
Pollution Control Federation.
3. Simplified Laboratory Procedures for Wastewater Examina-
tion. Available from the Water Pollution Control Federa-
tion.
4. Operation of Wastewater Treatment Plants. Available from
the Water Pollution Control Federation.
5. Manual of Wastewater Operations. Published by the Texas
Water Utilities Association.
6. Environmental Wastes Control Manual. Published annually /y
Public Works Magazine.
7. journal of the Water Pollution Control Federation.
167
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Provide Aids to External Relations
Treatment plant managers must interact with the general public and inter-
ested technical representatives. They must, therefore, be prepared to
provide information with respect to the technical capabilities and overall
operation of the plant. Activities which will assist management with external
relations of both technical and general interest classes are described below.
Suggesj: Publicity Charts and Similar Media
Visitors to treatment plants have an interest in how well wastewater is
treated before discharge; as taxpayers they have a right to know. By the
same token, plant personnel can take a certain amount of pride in being
a part of a smoothly functioning plant, and there is much to be gained by
dissemination of information to the public. One excellent way of provid-
ing plant performance feedback to the public and the plant staff is through
the use of graphs and charts posted in a conspicuous location. Performance
milestones, such as treatment standards, should be incorporated so that
a glance will tell if treatment objectives are being met or surpassed.
Much can be gained from taking a hard look at the accident prevention
statistics so often conspicuously displayed at industrial locations.
In addition to their publicity usefulness, graphs and charts are benefi-
cial to management, operations, and maintenance personnel in the detection
of trends and the spotting of trouble before a situation becomes critical.
Provide External Coordination Requirements
Changes in the residential and industrial growth patterns of a treatment
plant service area can have a dramatic influence on the treatment effective-
ness achieved by the plant. Management staffs must keep abreast of these
patterns so that any corrective actions can be initiated with enough lead
time to prevent treatment degradation. A valuable management aid is the
transformation of service area studies into a brief technical note to
168
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summarize the important characteristics to be carefully watched during
future years. The aid should account for the impact of such factors as:
1. Wastewater discharge ordinances.
2. Land use planning studies.
3. Zoning regulations.
The aid should provide guidance for establishing effective coordination
with industrial and residential agencies as a means for assessing the
impact of service area dynamics on treatment. For example, coordination
might be particularly important between management and the local agency
charged with responsibility for issuing building permits. Prior to issu-
ing an industrial building permit, the agency might refer the applicant to
treatment plant management for an assessment of potential waste discharges
and to be made aware of any pretreatment that might be required.
Provide Scheduling Aids
Scheduling is a key element of management responsibility, particularly
with respect to gaining the lead time required for new or updated
treatment plants.
Provide Work Schedules and Schedule Implications
Identify the tentative scheduling of all staff jobs to reflect the impli-
cations of shifts, seven-day operations, and any other factors bearing
upon the availability of adequate manpower resources. Provide management
with a rationale for how schedule modifications affect the availability of
resources. For example, assuming that maintenance and some other functions
are normally carried out during a regular daylight shift, some provision
must be made for the scheduling of ''on-call" work responsibility to take
care of emergency situations developing on other shifts.
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Provide Hiring Dates
Provide management with projected hiring dates to correspond with the
plant construction schedule. This information should tell management when
various members of the new staff should be "on-board" to undergo training,
become familiar with new equipment, or to release members of an existing
staff to attend training or take on new job responsibilities.
Provide Program Scheduling Aids
Critical path scheduling methods, such as the PERT technique, are an
invaluable aid to management. In essence, the work activities which must
be performed to complete a program are identified and the length of time
to complete them is estimated. The sequence in which the activities
must be completed will form a serial path, with generally some number of
parallel paths leading to the completed work effort. The longest path
determines the time required to complete the effort and is referred to
as the critical path. Activities, and the products resulting from each
activity, are normally shown in the form of a diagram keyed to a time
dimension.
Provide Budgeting Aids
Management cannot strive for cost-effectiveness without accounting for
two of the principal cost factors involved in fiscal planning: labor costs
and cost estimating for treatment as a function of loading and level of
treatment.
Project Labor Costs
Provide management with a general guide to the salary range for each of
the job titles provided in staffing information. The salary scales should
be based on supply and demand relationships in the local labor market from
which the staff will be acquired. The local offices of state employment
170
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services and other municipal plants in the area can probably provide the
necessary information. The objective must be to accurately judge what
monetary resources will be required for staffing so that a reasonable
estimate is provided for budgeting purposes in the municipal government.
If realistic amounts of salary monies are not initially appropriated,
it is unlikely that a properly trained, experienced, and motivated work
force can be acquired. Surveys of plant operations personnel have indi-
cated that salary aspects of pollution control work are in the greatest
need of improvement if good people are to be recruited and retained.
Provide Correlations of Treatment Level and Cost
Provide management with a basis for assessing the marginal cost for in-
creasing or decreasing the level of treatment provided by the plant. The
area of interest is, of course, centered around those operations, mainte-
nance, power consumption, and chemical costs which can quickly lead to
diminishing returns in treatment per unit of cost. Levels of treatment
below required standards are not within the region of concern. Limit cost
analysis to levels at or above required standards. The development of
this information will require answers to at least the following questions:
1. To what extent do dependent and independent variables of
treatment account for variations in treatment cost?
2. What conceptual relationships exist to provide a realistic
and dependable model for predicting the positive or negtive
cost increment when either the level of treatment or the
alternative control procedures for a process (and the
plant) are changed?
3. What mathematical relationships exist between cost and treat-
ment variables and how can these quantitative relationships
be capitalized upon for management control of the plant?
Answers to these questions are derived through testing the impact of var-
ious levels of effluent quality upon sensitive performance characteristics
171
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and then associating incremental costs for each viable option (see Step 2,
Delineate Plant Performance Characteristics).
Provide Aids to Operational Management
Management must be provided with a normative basis against which it can
assess plant and process performance. In general, this body of informa-
tion represents a management summary of the treatment criteria dealt with
in Chapter 2. Management should be able to use the information to deter-
mine if the plant is doing the job it was designed to do; and if the plant
is not meeting design objectives, the information should assist with local-
izing treatment problems.
Influent and Effluent Data
Management must be provided with a means for assessing the level of treat-
ment the plant is achieving with respect to influent loading. At least
the following factors must be incorporated into such a management tool:
1. Effluent concentration values—representing criterion
levels of treatment corresponding to a representative set
of influent hydraulic and concentration loading values.
2. Unit treatment outflow values—representing criterion treat-
ment levels for each plant process with respect to a repre-
sentative set of inflow hydraulic and concentration loadings.
3. Verification procedures—a listing of the procedures and
techniques for assessing observed versus theoretical influ-
ent and effluent values.
Relationships between influent and effluent characteristics should be ex-
pressed along the influent, external, and internal contingency dimensions
identified in Chapter 3. The tabular format illustrated in Figure 26 is
one possible means for expressing this information to management in sum-
mary form.
172
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DESIGN OBJECTIVES AND CRITERIA FOR PRIMARY SEDIMENTATION PROCESS
Plant Influent Loading
Design Loading:
Hydraulic :
2 . 5 mgd
Concentration :
BOD-560 ppm
COD- 3 80 ppm
SS-25 mg/1
Phos .
pH-6.8
Etc.
Selected Loadings :
A. Hydraulic: .5 mgd at
design concentration
shown above .
B. Hydraulic: 1.0 mgd at
design concentration
shown above .
C. Etc. to include all load-
ings and contingency param-
eters identified for the
plant design objectives
and criteria.
" — -~^~-~— __ ^ " —
Expected Outflow Quality
BOD
^
COD
/-
ss
- — - — -
DS
L— • — -_/~"-
Total
Solids
•^— — —
Etc.
/\
O)
o
CD
0
CO
to
O) CO
O (D
0 >
n .4-3
i
0 E
QJ +->
0 D-
C 0
fO
E cn
O T-
4- E
s- rs
O) CO
D_ CO
CO ^i —
CO O
O) rd S-
0 T- -)->
o s- c
S- 0) 0
D- -M O
— ^
Figure 26. Tabular Format for Expressing Objective and Criterion Outflow
Values According to Influent Loading
-------
Define Important Dynamic Relationships
As evaluative tools for management, steady-state relationships between
variables do not very often reflect reality. Time-based relationships
(or any other dynamic relationship), on the other hand, provide a realis-
tic tool for operational management and the assessment of plant perform-
ance.
The expression of dyanmic relationships can range from sophisticated
computer-based models to relatively simple, and yet meaningful and useful,
graphic means. Choose whatever means of expression will adequately serve
management needs without imposing unusual skill requirements or otherwise
exceeding in-house capabilities of the plant (such as might be the case
with a computer-based model). Figures 27 and 28 illustrate a simple
graphic means of expressing dynamic influent and effluent relationships
according to diurnal fluctuations in loading.
Other representative dynamic relationships include:
1. Day-to-day fluctuations in plant loading versus effluent
quality.
2. Seasonal fluctuations in plant loading versus effluent
quality.
3. Ambient temperature fluctuations versus effluent quality
for given levels of plant loading.
Provide Operations/Cost Relationships
Identify the cost relationships associated with the control variables of
major plant units in such a way as to make clear what operations options
are available and the cost increments (at least in rough measures) incurred
with each option. Combined power costs and maintenance labor costs might
reflect, for example, that it is more cost-effective to operate two pumps
intermittently than to run a single pump continuously.
174
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300
200
Influent
u
c
o
o
O
O
CQ
TOO
Effluent
•»««%•
12mi d
8
12n
12mid
Figure 27. Sample Graphic Expression of B.O.D,
Variations by Time of Day
300
O)
§ 200
o
oo
T3
O
oo
T3
0)
a)
Q.
CO
3
oo
100
12mi d
I I
8
12n
j I
8
12mid
Figure 28.
Sample Graphic Expression of Suspended
Solids Variation by Time of Day
175
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Recommend Operating Records
Treatment plant operating records are required to serve two primary func-
tions: to provide information for operational control, and to provide
historical records of plant performance for possible future needs. His-
torical data, in addition to being required by most regulatory agencies,
forms a base of data with wide applications in management decision making.
Important operating information to be provided to management includes:
1. Hydraulic loading.
2. Concentration loading.
3. Effluent quality.
4. Process status.
The specific variables to be measured, the measurement technique, frequency
of measurement, and other factors bearing on the data must also be pro-
vided. Sample data forms provide a convenient means for conveying appro-
priate operating data requirements.
Plant/Process Performance Models
Process and plant performance models should be developed which can be
directly applied to the operational status of the plant by management.
The desired models represent tools which are tailored for direct applica-
tion to management problems such as interpretation of how well the plant
is functioning, assisting with the isolation of treatment deficiencies,
and generally facilitating the decision-making role of management. Two
general objectives should always be to:
1. Present a model, or number of models, to describe the
individual operating characteristics of the plant.
2. Solve specific problems or test hypotheses about processes
and treatment characteristics based on models of operational
characteristics.
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Provide Architectural and Engineering Drawings
A complete set of the architectural and engineering drawings for the
treatment plant should be furnished to management for use as a functional
tool and as a permanent reference. The drawings should be keyed so that
a clear path is specified for relating one drawing to another and for
matching with comparable functional flow diagrams.
Provide Schematic Flow Diagrams
Functional schematics must be provided to supplement and clarify general
plan drawings. Separate schematics should be provided for each unit treat-
ment or other major treatment component as well as for the plant as a
whole. General plan drawings and functional schematics should be keyed so
that a hierarchy emerges wherein any element of the physical plant can be
traced to either engineering or functional descriptions.
Provide Verbal Descriptions of Plant Functions
Each functional component of the plant should be briefly and concisely
defined so that management will have a firm conceptual understanding of
how the plant operates. Both the positive and negative features of the
plant should be included in the verbal descriptions. Figure 29 illus-
trates how the verbal and functional descriptions might be combined.
Provide Aids to Maintenance Management
Maintenance aspects of treatment plants represent a very significant por-
tion of total monetary and human resource expenditures. Maintenance of
the plant, therefore, places a certain burden on management for constant
evaluation and optimization of maintenance programs, a function which can
be eased through the provision of appropriate management information.
The following activities and products are intended to serve at least some
of the essential needs for maintenance management:
177
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To Atmosphere
Spent
Carbon
Burners
Fuel
03
Scrubber
MULTIPLE-HEARTH REACTIVATION FURNACE
Spent carbon enters the top of the furnace.
An air-cooled rotating shaft, with rakes at
each hearth level, extends vertically through
the unit. The carbon is raked in a spiral
path moving in and out of each successive
hearth through alternate drop holes. Acti-
vated carbon discharged from the bottom
hearth at 500° F is completely reactivated
since all the organic matter has been burned
away. Combustion gases pass through a high-
efficiency wet scrubber.
Air
Rake
Drive
I Slurry
fReactivated " To
Carbon To Lagoon
Slurry Tank
Figure 29. Illustrative Schematic Flow Diagram and Corresponding Verbal Description
-------
Recommend Maintenance Records
Maintenance records must be developed which will serve as an effective
management tool for the overall evaluation, control, and direction of
plant maintenance. A plan for recording pertinent maintenance informa-
tion should be directed to at least the following elements of each unit
of plant facility and equipment requiring maintenance services:
1. Labor time devoted to routine preventive maintenance.
2. Labor time devoted to corrective maintenance.
3. Dates on which preventive and corrective maintenance
took place.
4. Hoursfthe unit was available for use.
5. Hours the unit was unavailable for use, by major class
of failure.
6. Name of person performing maintenance.
7. Cost of maintenance materials and parts consumed.
8. Observed symptoms indicating potential future maintenance
needs.
Provide a Maintenance Evaluation Plan
An evaluation plan should be provided, utilizing data from maintenance
records, to guide the overall analysis activities of management. The
plan should include methods and techniques which will allow:
1. Isolation of equipment with high failure rates.
2. Identification of major causes of failure.
3. Establishment of relationships and trends between preven-
tive maintenance schedules and equipment failure rates.
4. Formulation of equipment specifications which will alleviate
certain maintenance problems in any future purchases.
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Provide Aids to [Management of Purchased Services
It is generally impossible to acquire an in-house capability in all
required skills without creating grossly excessive labor costs. The fol-
lowing types of activities can provide management with information to
assist with outside-service decision making.
Identify Alternatives to Hiring
Identify any alternatives that may exist with respect to the acquisition
of manpower resources. For example, there may be advantages to having
contracted services until such time as an in-house capability can be
developed. Or, it may be possible to "borrow" resources from other munici-
pal manpower pools to assist during the period of acquiring a fully trained
and experienced plant personnel complement. Electricians, mechanics, and
other journeyman-level personnel are frequently available to perform work
in departments of the municipality other than that to which they are
assigned—if arrangements to this effect can be made in advance. Muni-
cipal water supply departments, where they exist, provide particularly
good opportunities for sharing the utilization and expense of maintenance
specialists because of the similarities in process equipment.
Identify In-House Versus Contractor Tradeoffs
On the basis of estimated manpower utilization (from staffing requirements
of Chapter 3), there is a possibility that some plant functions will
result in such low task loading that it is not prudent to employ a person
(or additional person). Describe the circumstances of each case, make
recommendations for either hiring or contracting for the services, and
make clear the tradeoffs involved in the decision to hire or contract.
Three of the important tradeoff considerations are:
1. Availability of personnel when required.
2. Cost of the two service options.
180
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3. Supply and spare parts inventories required for in-house
capability.
Assess each cost variable with respect to available alternatives and iden-
tify the conditions under which each alternative becomes a preferred
choice. For example, the overhauling of certain equipment might best be
handled through the manufacturer up to a certain number of units per month',
but if the number of overhauled units per month exceeds that number, it
becomes more cost-effective to develop an in-house capability. With
respect to another variable, such as replacement parts, there may be such
alternatives as: keeping no inventory; a small inventory with replacement
as use occurs; or, a large inventory to take advantage of discounts, with
the changeover point a function of failure rates, equipment criticality,
discount possibilities, and storage space for an inventory.
Provide Aids to Personnel Management
One of management's initial information needs is concerned with develop-
ment of a competent and properly motivated work force. Information useful
for this purpose must be provided to management early enough so that it
may be effectively applied to the acquisition and training of the proper
numbers and types of people prior to the time they are to assume their
assignments in the treatment plant. The following forms of information
are essential to the personnel and training activities of management.
Provide Job Descriptions
Provide complete job descriptions for each element of the required work
force. Appendix A provides the essential information to be included in
the job descriptions. In cases where there is an existing waste treat-
ment plant staff, such as with the updating of a plant or the addition of
a new plant to a multiple plant system, make comparisons between the new
jobs and those which currently exist in terms of numbers and the general
skill requirements.
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Provide a Staffing Plan
As described and illustrated in Chapter 3, provide a staffing plan to
summarize the required work force. Where there is an existing work force,
draw comparisons between what will be required and what already exists.
For example, indicate what ''old" jobs can be retained in the new manpower
structure with minimal additional training, what jobs will almost certainly
require the hiring of a new person, and so forth. An assessment of the
duties performed by the existing staff will, of course, have to be made.
Suggest an Organizational Structure
Recommend an organizational structure commensurate with the overall size
and general type of plant under consideration. The recommendations should
take into account the differences in staffing which may occur as the result
of the plant's gradually progressing from initial loading to conditions of
design loading, and any implications such changes may have on an initial
organizational structure. The recommended structure should be presented
in the form of an organizational flow chart to reflect lines of authority
as well as functional requirements within the treatment plant or system.
Suggest a Career Development Ladder
Provide some indication of how a career development hierarchy might be
established within the context of the plant or system which would allow
for monetary as well as technical, social, and self-esteem advancements.
Levels of certification, experience, formal training, job titles, and other
factors of the jobs should be examined for possible use as an advancement
vehicle. Turn to demonstrated examples of effective personnel policies
in other waste treatment plants for ideas.
Specify Certification Requirements
Regardless of whether local or state operator certification is mandatory,
specify appropriate levels of certification for all applicable job titles
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according to whatever classification system prevails for the jurisdic-
tional area of the plant.
Provide Guidance for Hiring Personnel
Provide management with general guidelines for hiring personnel in terms
of where the appropriate skills may be found. This information should
include recommendations for a recruiting effort, where the effort should
be directed, and some of the known media for reaching potential staff
members. The following should be considered:
Identify Schools. A listing of local public and private schools should
be provided for possible use in recruiting personnel, particularly entry
level personnel where prior waste treatment experience is relatively
unimportant. The same list of schools can also serve a useful function
for training purposes. A good starting place is the local high school,
where there is most often a guidance counselor knowledgeable about other
schools, vocational/technical courses available locally, and so forth.
Suggest Journals. There are many journals devoted to the field of waste-
water treatment which include an employment section for job openings and
people searching for jobs. The usefulness of journal advertising is
limited primarily to professional level jobs, but there may be recruiting
efforts where use of this media is warranted.
Interact with Unions. Where unionization of treatment plant personnel
has taken place, coordination of recruiting with the appropriate union (s)
can be beneficial to both the union and management.
Provide Aids to Data Management
Plant managers are heavily dependent on data of all types to make decisions
and to assess plant performance resulting from those decisions. There is,
of course, the need to assess the status of the plant at timely intervals
183
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and to determine the most cost-effective manner of treatment for given
conditions, both of these functions being partially served through appro-
priate operations and maintenance records. There may also be a need for
data to permit the exercise of plant models or to test specific hypotheses
with respect to a new or updated treatment plant.
Specify Data Collection Objectives
Provide management with a set of data collection objectives aimed at creat-
ing a total picture of plant operational status. The data objectives
should be aimed at revealing as many alternative views about management,
operations, and maintenance as possible. In all cases, the data collec-
tion objectives must be stated in such a way that collected data are refer-
enced to real or suspected treatment problems. That is, each data element
to be collected must be cross-referenced to the specific problem-solving
applications to which it can be applied.
Estimate Data Costs
Cost is an important consideration in setting data collection objectives
for management. In general the greater the amount of data collected, and
the accuracy with which it is collected, the greater the cost. Technical
considerations of data collection should be carefully evolved to avoid a
level of precision beyond management's needs and which would translate into
higher, and possibly unnecessary, data costs.
Identify Technical Considerations of the Data
There are several technical considerations which should be carefully con-
sidered in setting data collection objectives as well as management's
ability to apply the data. The following are some of the more important
technical considerations:
1. Bias is an important factor in sampling the population of
data relevant to treatment plant applications. Biases
184
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usually develop in connection with the judgments about the
range of variations in treatment practices, the consequences
of alternative practices, and the relative utility of one
treatment concept over another.
2• Precision of data may be increased or decreased by changing
the number of measurements with a given data method or by
alteration of the data method. Evaluate tradeoffs between
the two in terms of specific treatment system factors and
the cost of data collection.
3. Level of confidence should be established according to an
overall assessment of relevant factors, including the stage
of development, rather than some arbitrary value. The major
factor is the risk (or cost) of falsely accepting or reject-
ing data.
Linri t the Range
Surprising amounts of data collection can be realized for alternatives
that are not feasible or for a range of variation beyond what is necessary.
Weed out nonfeasible alternatives and limit the range of variables to a
realistic and necessary base.
Recommend In-House Research
Describe to management the nature of potential or real operational prob-
lems which might be solved through in-house research. Certain forms of
research can be carried out through the exclusive use of plant staff and
resources as long as sophisticated apparatus is not required and if a
research plan is sufficiently defined that advanced levels of skill are
not required for implementing or interpreting the results of the research.
Research plans presented to management should:
1. Briefly describe the problem.
2. Provide an approach for collecting required data.
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3. Provide a strategy for analyzing and interpreting the data.
4. Provide a summary of the benefits which could accrue from
the research findings.
Outline the Potential for Automatic Data Processing
Opportunities for automatic data processing should be investigated and
recommendations made to management. There is a considerable number of
computer programs available to reduce the clerical chores of maintaining
up-to-date management information. There is also a number of firms in
the business of taking more or less raw data from treatment plants,
processing it to produce incremental and historical comparisons along
many variables, and providing management summaries on a contract basis.
A listing of some of the currently available computer programs can be
obtained through:
Environmental Protection Agency
National Environmental Research Center
Treatment Optimization Research Program
Cincinnati, Ohio 45268
Figure 30 illustrates a consolidated summary of digester performance pro-
duced through a typical application of automatic data processing to stand-
ard elements of operating data.
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FINAL TABULATION
TREATMENT PLANT-SLUDGE
•
'. DATE HOUR
*
'.
3/01/67
. 3/02/67
3/03/67
3/04/b7
3/05/67
3/06/67
. 3/07/67
. 3/08/67
. 3/09/67
, 3/10/67
3/12/67
. 3/13/67
• 3/14/67
3/I5/6/
3/16/67
. 3/17/67
• 3/2U/67
• 3/21/67
. 3/22/67
. 3/23/67
. 3/24/67
• 3/25/67
* 3/26/67
3/27/67
3/28/67
3/29/67
3/3U/67
| 3/31/67
AVERAGE
MAXIMUM
MINIMUM
\ TOTALS
LAB
bAMPLE
NO
30018
3U068
30116
30154
30173
30189
30260
30328
30362
30397
30447
30466
30b29
30681
30727
30769
30834
30865
30945
31000
31037
31065
31081
31098
31129
31164
31203
31240
PH
6.
7.
6.
6.
7.
7.
7.
6.
7.
7.
7.
7.
7.
7.
7.
7.
6.
6.
7.
6.
7.
6.
6.
7.
7
7.
6
6
7
7
6
SAMPLING
9
0
9
9
0
0
0
y
0
i
0
1
0
0
0
0
9
9
0
8
0
9
7
1
2
0
9
9
0
2
7
TOTAL
SOLIDS
%
2.8
3.2
3.2
2.8
3.0
3.3
3.2
3.0
1.9
2.9
2.6
2.6
2.6
2.5
2.8
3.3
1.9
AND TESTING
VOLATILE
PROGRAM
TOTAL
SOLIDS VOLATILE
%
1.4
l.b
1.4
1.4
1.4
1.5
1.4
1.3
.9
1.3
1.2
1.3
1.4
1.3
1.3
l.b
.9
%
47.9
46.6
44.0
49.3
47.2
45.3
43.5
44.4
46.9
44.2
45.6
50.0
b3.7
51.9
47.2
53.7
43.5
>
2 STATION 5
VOLATILE
ACIDS
MG-L AS HOAC
223
240
189
206
223
172
206
309
223
274
172
154
172
206
172
120
137
240
378
463
618
635
755
806
806
858
909
858
383
909
120
NO 4
B.O.D.
MG-L
8
3
5
4
4
6
4
3
5
4
5
4
4
7,
5
8
3
71
,400
,780
,100
,200
,200
,000
,200
,660
,100
,140
,700
,680
,380
500
,074
,400
,660
,040
MAR 31 , 1967 PAGE 17
RECIRC
TOTAL SAND OIL &
ALKALINITY % GREASE
MG-L Ab CAC03 %
2,900
3,060
3,150
2,850
3,000
2,950
3,000
3,000
3,i;00
3,250
3,150
3,100
3,400
3,050
2,950
2.950
2,6bO
2,700
2,750
2,500
2,800
2,500
2,900
2,950
3,200
2,900
2,850
2,900
2,948 .0 .0
3,400 .0 .0
2,500 .0 .0
ACCURAY
% SOLIDS
%
.0
.0
.0
" MONTHLY SUMMARY OF TESTING DATA
% REDUCTION
% REDUCTION
% REDUCTION
,1^-^^ % REDUCTION
OF VOLATILE
OF VOLATILE
OF VOLATILE
OF VOLATILE
SOLIDS
SOLIDS
SOLIDS
SOLIDS
IN DIGESTER 1 =
IN DIGESTER 2 =
IN DIGESTER 3 =
IN DIGESTER 4 =
62
49
70
.26
.00
.05
.68
__/ —
Figure 30. Sample Printout of Digester Performance
Produced Through Automatic Data Processing
-------
APPENDIX C
CLASSIFICATION AND DESCRIPTION
OF INFORMATIONAL JOB AIDS FOR OPERATORS
This appendix provides recommendations for job aids to assist operators
with their functional role and responsibilities within the treatment plant
The appendix is structured through a classification of major information
content areas deemed appropriate to operational activities. Within each
content area, a finer level of detail is provided for classes of informa-
tion to be presented to operator personnel along with corresponding rec-
ommendations for appropriate job aid(s) for presenting the information
effectively. The classes of information are intended to be self-explanatoj
The mode(s) of job aid presentation, keyed to information classes in the
form of matrices, is defined in Chapter 4, along with principles and pro-
cedures for development.
The intent is not to dictate information needs of operators nor to specify
what form of job aid must be used for its presentation. Rather, the intent
is to suggest what is likely to be appropriate in terms of both content
and alternative job aid formats. The final selection must be guided by
specific plant circumstances.
Major content areas considered are:
1. Aids to process startup.
2. Process control aids.
3. Aids to process stabilization.
4. Aids to servicing procedures.
5. Aids to maintenance coordination.
6. Reporting aids.
188
-------
Aids to Process Startup
The "startup" of biological forms of wastewater treatment represent spe-
cial cases for treatment operations; special control procedures are
required to foster development of the proper numbers and types of biologi-
cal growths prior to the introduction of full-scale loading. The need
for special startup information will exist at the time the plant initially
goes into operation and thereafter as determined by process failures.
Table 5 presents some representative types of "startup" information of
value to operators and some suggested formats for presentation through job
aids.
Figure 31 illustrates a possible job aid format for the presentation of
conditions and criteria necessary for startup of an activated sludge
process. Individual aids, as well as combinations of aids, must be
utilized to effectively communicate startup information to plant operators.
Process Control Aids
Process control aids present information, tailored to the specific size
and configuration of the concerned plant, to assist with the monitoring
and effective control of treatment processes. The control information
to be presented is based on treatment plant objectives and criteria for
the range of loading and other parameters to which the plant is subjected.
Control loops for each controllable treatment parameter, in conjunction
with objectives and criteria, represent the principal framework for deriv-
ing the information needs of operators with vaspect to controlling treat-
ment processes.
Table 6 reflects at least some of the important units of process control
information to be presented to operators and some suggested forms of job
aids appropriate to each type of information. Nearly all of the information
189
-------
Table 5
Elements of Startup Information for Biological Treatments
and Some Appropriate Forms of Presentation Through Job Aids
^^^ Suggested Mode(s) of
^^^ Job Aid Presentation
Class of Startup ^^^
Information to be ^^^^
Presented to Operators ^^^
Facility and equipment conditions
for startup
Loading parameters and values for
startup (waste to micro-organism
ratio)
Recommended method (s) for starting
biological growth
Types and ratio or preferred micro-
organisms
Instructions for controlling the
growth and predominance of pre-
ferred micro-organisms
Instructions for controlling the
metalobic rate in early stages of
growth
Recommended types of food matter
Effects of temperature on growth
characteristics
Effects of oxygen on growth char-
acteristics
Methods of inhibiting the growth of
undesirable micro-organisms
Values and conditions for transfer
to full-scale treatment
Instructions for converting to
full-scale treatment
Manual (s) 1
X
X
X
X
X
X
X
X
X
X
X
X
[Detailed Task Proce- 1
dure Information |
X
X
X
X
X
[Reference Material 1
(special purpose) |
X
X
X
1 Model/Simulation/ 1
Example |
X
X
X
X
Checklist (s) 1
X
X
X
X
1 Troubleshooting Action 1
Trees/Decision Tables 1
X
X
(Function Flow 1
Logic Diagrams |
X
X
190
-------
STARTUP CONDITIONS AND CRITERIA FOR ACTIVATED SLUDGE
Item or Condition
Micro-organisms
Feed characteristics
Temperature
pH
Air requirements
Aeration period
Sludge age
BOD loading
Sludge quantity
Sludge quality
Startup Criteria
A varied culture of different types of bacteria
with zooglea ramigara and/or other gel formers
present; stalked, ciliate protozoa and free swim-
ming ciliates present without the smaller flagel-
late protozoa; absence of the fungus, sphaerotilus
natans .
The raw sewage to be predominantly composed of a
mixture of soluable, colloidal, and suspended
materials; soluable BOD being more difficult to
process especially at lower temperatures. For
average domestic sewage, the feed should contain
between 8 and 18 ppm free amonia as N and between
1.7 and 218 ppm phosphorus as P; the raw sewage
must be free of toxic materials.
Optimum temperature of 82 degrees F.
Between 7 . 0 and 7.5.
a. 0.5 to 1.5 cu. ft. of free air per gallon of
sewage .
b. 500 to 700 cu. ft. per Ib. of BOD removed
when BOD loading 25 to 30 Ib. per 100 Ib.
aerator solids .
c. 700 to 1750 cu. ft. per Ib. of BOD removed
when BOD loading 25 to 12 Ib. per 100 Ib of
aerator suspended solids.
5 to 7 hours with diffused air.
3 to 4 days.
a. 25 to 30 Ibs of BOD per 1000 cu. ft. of aera-
tion tank.
b. 30 to 40 Ib of BOD per 100 Ib. of aerator sus-
pended solids.
c. 20 to 30 Ib. of BOD per 100 Ib . of aerator
suspended solids at reduced flows.
1500 to 3000 ppm aerator suspended solids.
Volatile matter — 60 to 85% of total aerator solids.
Alkalinity — 100 to 200 ppm.
Dissolved oxygen content at outlet — 2.0 to 5.0 ppm.
30 minute settling test — 15 to 25%.
Sludge volume index — near 100.
Figure 31. Illustrative Tabular Job Aid Presenting Startup
Criteria for an Activated Sludge Process
191
-------
Table 6
Elements of Process Control Information and Some
Appropriate Job Aid Forms of Presentation
^^^ Suggested Mode(s) of
^^^ Job Aid Presentation
Class of Process ^^^
Information to be ^^sw
Presented to Operators ^^V.
Process performance parameters to
be checked
Suggested intervals for performance
checks
Standard values or conditions
indicative of acceptable process/
plant performance
Values or conditions indicative of
unacceptable performance
Relationship between observed status
and required control changes
Identifying proper control change
for given process/plant conditions
Instructions for carrying out con-
trol changes
Symptoms of control problems and
the nature of associated problems
Techniques for isolating control
problems
Contingency situations and appro-
priate emergency procedures
Interprocess relationships on
treatment control
Tradeoff factors in optimizing
treatment cost effectiveness
Detailed Task Proce- 1
dural Information |
X
X
X
Manual (s) |
X
X
X
X
X
X
X
X
X
X
X
X
Reference Material 1
(special purpose) |
X
X
X
X
X
X
1 Model/Simulation/ 1
Example 1
X
X
X
X
ITask Performance I
Schedule (s) |
X
1 Process Equipment 1
and Control Labels 1
X
Cue Materials 1
X
X
X
X
| Checklist (s) |
X
X
1 Troubleshooting Action 1
Trees/Decision Tables |
X
X
X
Function Flow 1
1 Logic Diagrams |
X
X
X
X
192
-------
should, of course, be presented in a consolidated manual, but individual
aids also need to be designed for use at control task locations.
Figure 32 illustrates a possible job aid format for presenting symptoms
of digester control problems and related alternatives which could cause
the problems.
Code Labels. Operator access to information can be enhanced through the
labeling of operational components of the plant which correspond with keys,
indexes, sections of manuals, and other information storage sources.
Control Relationships. Control relationships should be posted at con-
trols to the maximum extent possible. For example, if flow rate has an
effect on the optimal on/off ratio of an equipment unit, the optimal
ratio might be posted in the form of a graph as illustrated in Figure 33.
In other control situations, as depicted in Figure 34, it may only be
necessary to provide a checklist of alternative control factors.
Aids to Process Stabilization
Process stabilization refers to the relatively steady-state level of
treatment effectiveness desirable for a plant in spite of nonsteady-state
loading and other factors impacting on treatment effectiveness. Process
stabilization implies operational control of processes in such a manner
that loading and other factors are anticipated and control adjustments made
so that process and plant effluents meet criterion on a continuing basis.
Table 7 reflects some important categories of information to assist with
achieving process stabilization and some corresponding job aid types for
the presentation of information to plant operations personnel.
Figure 35 is a sample job aid format for presenting information concerned
with toxic elements.
193
-------
^^^^^ Possible Failure
^^^^^ Cause
Digester Failure ^^^^^
Symptom ^^^^^
Decreased methane production
Immediate increase in carbon
dioxide with decrease in methane
Increased carbon dioxide with
decreased methane production
Increased volatile acids
Rapid increase in volatile acids
with decrease in alkalinity
Decreasing alkalinity
Increased ammonia alkalinity
Increased percentage of carbon
dioxide
Decrease in digester temperature
pH drop
Foul smelling supernatant
Overloading 1
X
X
X
X
Excessive
Sludge
Withdrawal
X
X
X
Feeding Sludges
Above Normal
Concentration
X
X
X
X
X
Feeding
Voluminous
Sludges
Below Normal
Concentration
X
X
X
X
Figure 32.
Illustrative Operations Job Aid for Identifying Digester
Failure Possibilities According to Observable Symptoms
3 0
20
1 0
I I
I
• => -b - / -8 ,9 1,0 1:1 1.2 1.3
On Time/Off Time
Figure 33. Sample Aid for Checking and Setting Control Point
194
-------
OXYGEN CONTROL FACTORS FOR AERATION TANK
Increase Dissolved Oxygen by:
Increasing blower speed
Starting additional blower
Decreasing food supply/sewage flow
Placing more aeration tanks into
operation
Bypassing part of aeration tank
influent (ONLY AS A LAST RESORT)
Decrease Dissolved Oxygen by:
Decreasing blower speed
Shutting off a blower
Wasting air to the atmosphere
Increasing sewage rate of flow
Taking aeration tanks out of opera-
tion.
Bypassing all or part of raw sewage
directly to the aeration tanks
Figure 34. Sample Job Aid for the Control of
Dissolved Oxygen in an Aeration Tank
SAFE LIMITS FOR TOXIC ELEMENTS
Waste Element
Chromium as Cr (hexavalent)
Copper
Cyanides
Acids or alkalies
Phenol or equivalent
Formaldehyde
Oils and greases
Zinc, Nickel, Mercury, Lead,
Arsenic
Maximum Safe Limit in Raw Sewage
3 ppm
1 ppm
2 ppm
pH range of 6.0 to 9.5
50 ppm
Undesirable in any quantity
100 ppm
Undesirable; safe limits not estab-
lished
Figure 35. Illustrative Checklist for Use in
Reviewing the Results of Laboratory
Analysis
195
-------
Table 7
Elements of Process Stabilization and Some
Appropriate Forms of Job Aid Presentation
^^^ Suggested Mode(s) of
^^^ Job Aid Presentation
Class of Process ^^W
Stabilization Information ^^^
to be Presented to Operators ^^^
Treatment process objectives and
criteria
Cost and level of treatment as
function of hydraulic and concen-
tration loading
Cost and level of treatment com-
promise points
Methods for establishing cost/level
of treatment stabilization points
Control adjustments for maintaining
stability through diurnal and other
normal fluctuations in loading
Shock loading conditions which can
destroy treatment stabilization
Symptoms and warning signs of
shock loading
Preventive measures for shock
loading
Contingency situations and effects
upon reaching and maintaining
treatment criteria
Procedures for dealing with con-
tingency situations
Toxic elements and safe limits for
maintaining stabilization
Procedures for dealing with process
instability
Evaluation plan for assessing pro-
cess performance
[Manual (s) |
X
X
X
X
X
X
X
X
X
X
X
X
X
1 Detailed Task Procedure 1
Information |
X
X
X
X
X
(Reference Material 1
(special purpose) 1
X
X
X
X
1 Model/Simulation/ 1
Example I
X
X
X
ITask Performance I
Schedule ]
X
X
Checklist (s) I
X
X
X
X
X
X
1 Troubleshooting Action I
Trees/Decision Tables I
X
X
Function Flow 1
[Logic Diagrams j
X
X
X
(Graphs and Nomographs |
X
196
-------
Aids to Servicing Procedures
There is almost always a number of relatively unsophisticated maintenance
tasks, primarily in the areas of simple "servicing" procedures, which can
be efficiently performed by operators rather than complicating the issue
by having to call upon maintenance personnel. A common example is the
refilling of pens on chart recorders.
The responsibility for servicing tasks, or perhaps even dual responsibility
with maintenance personnel in some cases, must, of course, be designated
as part of job description.
Job aids for servicing tasks assigned to operations personnel should be
developed according to the recommendations provided in Appendix D under
the heading of "Aids to Preventive Maintenance." Any other "maintenance-
oriented" tasks assigned to operator personnel can also benefit from the
overall recommendations provided in Appendix D.
Aids to Maintenance Coordination
Operations personnel are in almost continuous contact with plant facility
and equipment. They are, therefore, in a position where they are likely
to identify maintenance needs before they might normally be detected by
the maintenance staff. The means for detecting and reporting maintenance
problems requiring immediate or near-future attention must be provided to
the operations staff. In addition, procedures for controlling treatment
during periods of equipment malfunction or "outage" must be provided as
part of overall plant contingency planning.
Table 8 indicates Some of the maintenance coordination information and
products which should be developed to assist operators with their role
in effective maintenance. The suggested job aid formats are intended to
provide starting points for information presentation.
197
-------
Table 8
Elements of Maintenance Coordination
and Related Recommendations for Job Aids
^V^ Suggested Mode(s) of
^^^ Job Aid Presentation
Types of Maintenance ^^^
Coordination Information ^^^
to be Presented to Operators^^^
Symptoms of equipment malfunctions
which should be regularly checked
by operations personnel
Procedures for communicating main-
tenance needs to maintenance/man-
agement personnel
Recommended maintenance request
form:
Description of observed
malfunction
Equipment unit malfunctioning
Location/serial number as
required
Criticality of malfunction to
operational effectiveness of
treatment
Date and time malfunction
observed
Name of person reporting
malfunction
Instructions for minimizing the
effects of malfunctioning equipment
on treatment
Instructions for operating treat-
ment processes during periods of
specific equipment outage for
maintenance
1 Manual (s) 1
X
X
X
X
Detailed Procedural 1
Information 1
X
X
[Reference Material 1
(special purpose) 1
X
1 Model/Simulation/ 1
Example 1
X
X
Cue Materials 1
X
j Checklist (s) |
X
X
X
1 Troubleshooting Action 1
Trees/Decision Tables 1
X
X
(Function Flow 1
Logic Diagrams 1
X
X
IForm for Recording and 1
Transmitting Maint. Inf o . |
X
X
X
X
X
X
198
-------
Figure 36 provides a sample format for one possible type of maintenance
request form.
Reporting Aids
Documents concerned with the operational status of a treatment plant are
essential to operational control, assessment of plant effectiveness, plant
management, and the detection and analysis of trends for the treatment
of wastewater. Specifications of appropriate information to be collected
and reported by operators represent a major first step in what should be
a continuing program of plant evaluation, and subsequent modifications,
leading to maximal cost-effectiveness.
Table 9 reflects some informational elements to assist operators with the
collection and reporting of appropriate information. The table also pro-
vides suggested aids to assist with the collection and reporting of each
information type.
199
-------
MAINTENANCE REQUEST FORM
Date "7/^,0 (' "? 7—
Time S.'-Ho P»V\
Equipment Description:
p-wwy>
Location:
K'V Jt'tLU-M^v-u
«
Problem:
' ^ . ''
ov\- c|-l .XAA^X! n^vrvp ^w^-K,..
Criticality:
^ £ftf
Signature:
. "'
Figure 36. Sample Maintenance Request Form
200
-------
Table 9
Elements of Operational Data to be Documented and Some
Related Job Aids and Documentation Methods
Suggested Mode(si ot
Job Aid Presentation
Types of Reporting
Information to be Presented
to Operators
3
CJi
o
-p
a)
ft
O
rH
(0
•H
L)
Q)
•O K
Q) E
-P ft
-P O
(0 li-
ft -P
O H
M-l 0
0) ft
^ 0)
ffl 4J
0i M
m o
c ft
n3 Q)
S K
a
-p 13
to s-i
o o
u u
o
0)
-p
-I-' C
e -p
M C
O 3
in O
Q) U
h O
Techniques for processing and drawing
conclusions from operations data
i
Procedures for collecting and reportinc
operations data
Guidelines for collection and reporting
of specific data elements:
Raw waste volumes and characteristics
Treatment quality as function o±
loadina
Unusual loadinc
tions
treatment situa-
X X
Major acconplishner.ts a
backs encountered
nd or set-
Documentation of treatment failures
and/or inability to meet criteria
Data which may help in isolating the
cause of failures; i.e., symptoms,
conditions, etc.
Labor time charged by operators
against unit treatments (or more
detailed functional elements)
Consumables and other nonlabor
treatment cost elements
Information to be transferred frcm shift
to shift, operator to operator, and of
historical value
201
-------
APPENDIX D
CLASSIFICATION AND DESCRIPTION OF INFORMATIONAL JOB
AIDS FOR MAINTENANCE PERSONNEL
This appendix provides recommendations for job aids to assist maintenance
personnel with their responsibilities in the treatment plant. A classi-
fication of major content areas forms the primary structure for the appen-
dix, with a finer level of detail provided within-each content area.
Classes of pertinent maintenance information are keyed to recommended job
aid presentation modes through the use of matrices. As with the previous
appendix, more complete definition of the various job aids and procedures
for their development will require reference back to Chapter 4.
The major content areas considered are:
1. Aids to preventive maintenance.
2. Alignment and adjustment aids.
3. Diagnostic and troubleshooting aids.
4. Repair and overhaul aids.
5. Reporting aids.
Aids to Preventive Maintenance
Preventive maintenance, in the context of this appendix, refers to all
maintenance activities directed to the routine servicing and preservation
of equipment and facility to reduce the probability of unexpected failure
and increase life expectancy. For the purposes of this Guide, all mainte-
nance activities not performed for the express purpose of correcting a
failure are arbitrarily considered preventive maintenance and include such
tasks as lubrication, cleaning, and painting.
Table 10 lists some of the essential types of preventive maintenance
information to be presented to maintenance personnel as well as some job
aid formats applicable to each information types.
202
-------
Table 10
Essential Elements of Preventive Maintenance
Information and Related Recommendations for Job Aids
Suggested Mode(s) of
Job Aid Presentation
Types of Preventive
Maintenance Information
to be Presented to Mainte-
nance Personnel
c
(C
a
M
3
T3 fi
a) o
o -H
o -P
M (0
ft S
,x o
W M-l
id C
EH H
•H
r-l
u
0)
tn
a
•H CO
M -P
0) G
-P
C
OJ
e
ft
-H
W
W
0)
ft
-a
a)
-P
(C
o
O
nJ
u
td
4J
-P
c
0)
Enumeration of equipment and facility
requiring scheduled checks or inspections
Enumeration of equipment and facility
having service requirements (i.e.,
lubrication, etc.)
Recommended frequency for check, inspec-
tion, service tasks
Enumeration of equipment, tools, or
materials for each preventive mainte-
nance task
X
X
Procedures for performing check,
inspection, service tasks
Control settings and conditions required
for performing checks and inspections
Tolerances or conditions indicative of
proper or inadequate equipment function-
ing (malfunction symptoms)
X
Procedures for measuring tolerances or
perceiving need for maintenance actions
Method for recording when last equipment
service was provided
Method for noting when next equipment
service will be required
203
-------
Figure 37 is an example of a preventive maintenance schedule designed for
use at the equipment location. The example combines some of the features
of a checklist with a convenient means for determining when lubrication
was last performed and when it is again due, as well as who performed the
lubrication.
Alignment and Adjustment Aids
Alignment and adjustment activities refer to those aspects of maintenance
designed to compensate for wear and "drifting" of equipment through normal
use. The objective of alignment and adjustment activities is to keep
equipment "peaked" at the most desirable level of performance and prevent
out-of-tolerance conditions which could bear upon treatment effectiveness,
treatment costs, or a reduction in equipment life.
Table 11 identifies some information types deemed essential to alignment
and adjustment activities of maintenance personnel and a number of possible
forms of presentation of the information as job aids.
Diagnostic and Troubleshooting Aids
The ability of maintenance personnel to correct equipment failures is, in
many cases, a function of their ability to focus-in on the cause of the
failure. Once the problem is properly diagnosed, the repair or replace-
ment of faulty components is relatively routine. This particular section
is intended to enhance the ability of maintenance personnel to quickly
and accurately diagnose the corrective action necessary to put faulty
equipment back into service.
The types of information which can effectively enhance and support the
troubleshooting of plant equipment are presented in Table 12. Suggested
formats for presenting the information to maintenance personnel as job
aids is also presented.
204
-------
LUBRICATION SCHEDULE
(Keep Posted at Primary Tank #2)
TRANSFER CASE— Drain and refill every 6 months; 90 weight hypoid oil
Date of Change
Changed By Change Due On
UNIVERSAL JOINTS--Grease weekly; high-pressure lithium grease
Date
Lubricated By
Date
^^ ""\
^~
^
^_
\.
Lubricated By
\
V
^-— ——____— — --'x"
Figure 37. Example of a Service Schedule Designed
for Posting at Task Site
205
-------
Table 11
Elements of Alignment and Adjustment Information and
Some Appropriate Forms of Job Aid Presentation
Suggested Mode(s) of
Job Aid Presentation
Types of Align-
ment and Adjustment
Information to be
Presented to Mainte-
nance Personnel
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Table 12
Categories of Troubleshooting Information and
Some Related Job Aid Forms of Presentation
^^ Suggested Mode(s) of
^W Job Aid Presenta-
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^^^
^^t
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Types of ^W
Troubleshoot- ^^
ing Information ^^
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Enumeration of failure modes
for each unit of equipment
subject to a failure
Reliability information and
failure probabilities for
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Failure symptoms and charac-
teristics for failure modes
Control settings and condi-
tions required for diagnostic
tests
Tools/instruments required
for troubleshooting
Procedures for removing or
disassembling equipment for
the purpose of diagnosis
Procedures for measuring or
assessing components for
failures or defects
Reference information keyed
to appropriate repair or
replace tasks
^
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207
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Repair and Overhaul Aids
The repair or overhaul of treatment equipment is designed to correct
equipment which has malfunctioned or has worn to the extent of being non-
serviceable.
Table 13 identifies some of the essential forms of information required
for repairing and overhauling equipment. The table also reflects some
job aids appropriate to each type of repair and overhaul information.
It should be noted that, while many major repairs and overhauls are carried
out under maintenance contracts rather than through in-house resources, it
is, nevertheless, desirable to develop informational job aids for all
equipment units. Otherwise, the lack of appropriate job aids for some
equipment units will significantly dampen future options to develop an
in-house capability for their repair and overhaul.
Reporting Aids
The operational availability and reliability of treatment plant equipment,
the nature of current and anticipated maintenance problems, and the costs
of maintenance represent important decision-making information for both
maintenance and management personnel. Maintenance data are essential to a
workable maintenance philosophy, the detection and analysis of maintenance
trends, and the assessment of equipment reliability and maintainability
as input to cost-effective future purchases.
Table 14 presents a number of essential information types to be presented
to maintenance personnel to assist them in the reporting of relevant
maintenance data. Some job aid techniques are suggested for presenting
the information to maintenance personnel and to assist with their report-
ing function.
Figures 38 and 39 illustrate some of the possible job aids for recording
and reporting maintenance information.
208
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Table 13
Categories of Overhaul and Repair
Information and Some Related Forms of Job Aid Presentation
^^^^ Suggested Mode(s) of
^^^^ Job Aid Presentation
Types of Overhaul ^^^^
and Repair Information ^^^^
to be Presented to Mainte- ^^^^
nance Personnel ^^^^
Design information for each unit
of equipment
Corrective maintenance informa-
tion for each unit of equipment
Method for providing rapid access
to essential equipment information
Tools and facility required for
removal/replacement of component
parts and/or overhaul
Enumeration of tasks to be per-
formed in-plant and those requir-
ing outside services
Enumeration of tasks for repairing
specific equipment functions
Enumeration and sequencing of
tasks for complete overhaul of
equipment units
Tolerances for repair/replace
decision making
Instructions for measuring
tolerances
Procedures for repairing or refin-
ishing component parts
Information for ordering and stock-
ing spare parts (local sales outlet,
local service representatives, etc.)
Recommended inventory of spare parts
and supplies
Manual (s) |
X
X
X
X
X
X
X
X
X
X
X
X
|(asod;md jpToads)
uoTq.Buu:ojui
-[Bjnpaooa
-------
Table 14
Essential Elements of Maintenance Data and Some Related
Job Aids and Methods of Reporting
^^^^ Suggested Mode(s) of Job
^^Nw Aid Presentation
Types of Data Record- ^^^^
ing and Reporting Infor- ^^*»^^
mation to be Presented to ^^^^
Maintenance Personnel ^^^^^
Procedures for recording and reporting
equipment problems and recommendations
for future overhaul/purchases
Procedures for recording and reporting
pertinent information about the status
of plant equipment and facility
Procedures for recording and reporting
cost data:
Labor costs for corrective mainte-
nance
Parts and materials for corrective
maintenance
Labor costs for preventive main-
tenance
Materials consumed for preventive
maintenance
Cost of contracted maintenance
services
Procedures for compiling and utilizing
reliability information
Procedures for assessing impact of
maintenance task scheduling
Guidelines for an equipment data file
to record maintenance history of
equipment units
Manual (s) 1
X
X
X
X
X
X
X
X
X
X
Maintenance Log 1
X
(Management Summary 1
Reports |
X
X
Equipment Data Cards 1
X
X
1 Preformatted Special!
Report Forms I
X
X
(Preformatted Cost 1
Accounting Records 1
X
X
X
X
X
210
-------
INSPECTION SHEET—SETTLING TANKS
Date
Inspected by
Tank Number
Gear Box and Sprocket
Bull Sprocket
Drive Chain
Driven Sprockets
Flight Chain
Flights and Shoes
Rails
Service or
Adjustments Made:
Description of
Repairs to be Made:
(requiring down time)
#1
#2
#3
j
Remarks :
i
Figure 38, Combination Checklist and Inspection Report Form
-------
EQUIPMENT DATA CARD
Equip. Nomenclature
Location in Plant
Equip, #
Mfg.
Type
Address
Model
Serial #
Serv. Rep.
Phone
RPM
Vari-Drive Type
Capacity
Vari-Drive Serial #
Bearings
Mfg. & Part #
Shaft Size
Coupling
Belts
Ball
Type
Type
Roller
Mfg.
Size
Sleeve
Serial #
Cat. #
Packing
References
rype
Dwgs #s
Size
Maintenance Manual #s
Number Rings
Operations Manual #s
Recommended Brand
Date Installed:
Location:
Application:
Date
Repaired
Repairs or
Parts Replaced
Cause
Total
Repair Cost
(Service Record Continued on Reverse Side of Form)
Figure 39. Illustrative Form for Recording Pertinent
Equipment Data and Service Information
212
OU.S. GOVERNMENT PRINTING OFFICE: 1973
546-308/14 1-3
-------
SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
i. Report No,
w
GUIDE TO THE PREPARATION OF OPERATIONAL PLANS FOR
SEWAGE TREATMENT FACILITIES
Seller, E. L. and Altman, J. W.
Synectics Corporation
4790 William Flynn Highway
Allison Park, Pennsylvania 15101
12. Ssf«re
6.
H. £'jrtorm~j/
RepotfWo.,
17090FWA
#68-01-0073
Type-.-{ RepQi-i and
Period Covered
A proceduralized methodology is provided to guide the initial and ongoing planning neces-
sary for extracting maximum potential from wastewater treatment plants. The objective
of the planning activities is the development of conceptual and applied tools for direct
use by plant personnel in optimizing the cost^-effectiveness of their plant, complementinc
the design engineering of the physical plant.
The main body of the Guide is'divided into five major steps, representing a procedural-
ized methodology for 'developing operational planning materials. The contents and
sequencing of these steps are designed to rationally combine operational planning and
design engineering. Heavy emphasis is placed on general methods and principles which
can be applied to a wide variety of specific treatment plant designs and situations.
The four appendixes of the Guide provide a detailed classification and description of
planning materials deemed ess.ential to plant functions of management, operations, and
maintenance. Job descriptions, plant manuals, checklists, reference materials, task
schedules, decision tables, and operating records are among the specific materials
designed to'support the above personnel functions. Thus, the appendixes serve to define
the nature of the planning outputs while the five procedural steps of the main body
provide a framework for their development.
ITa. Descripton,-
*Management planning, *0perations research, *0peration and maintenance, *0ptimization,
*Humari engineering, job analysis, manpower, systems engineering, human resources,
operations, operating criteria, information systems, manuals, plant records
17b. Identifiers
Job aids, performance standards, performance aids, management data, operator data,
maintenance data
l~r. COWR.\ Fhl'l
06A , 05D
a'rit? Class.
: ,"' -i-. . -'
''0. Se: irJtyCl-,$s.
-21 No. of
Pages
,'2. Pi-ice
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 2O24O
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