ASSESSMENT AND STRATEGY FOR AUTOMATED PROCESS CONTROL
IN
WASTEWATER TREATMENT
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO
JULY 1980
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ASSESSMENT AND STRATEGY FOR AUTOMATED PROCESS CONTROL
IN
WASTEWATER TREATMENT
The problems in O&M and plant performance at wastewater treatment plants
have been classified and well documented by the Municipal Environmental
Research Laboratory's National Operational and Maintenance Cause and Effect
Survey (1,2,3). The Survey evaluated and ranked 70 different factors
contributing to poor plant performance. The results of this survey at plants
of 10 MGD and less are likely also to be generally applicable, with perhaps
changes in ranking, to the larger treatment plants. The major causes of poor
plant performance, in order of importance, from that survey are:
1. Improper operator application of concepts and
testing to process control.
2. Inadequate Process Control Testing Procedures.
3. Excessive infiltration/inflow.
4. Inadequate operator understanding of wastewater treatment.
5. Improper technical guidances.
6. Inadequate,sludge wasting capabilities.
/
7. Inadequate process controllability.
8. Inadequate process flexibility.
9. Ineffective O&M Manual Instruction.
10. Deficiencies in Aerator Design.
The MERL's O&M Program has further demonstrated and the Agency has
implemented an approach (4) for improving plant performance. In MERL's survey,
poor performance at plants was always caused by a combination of factors. The
MERL approach, called the Composite Correction Program (CCP), was developed and
found to satisfactorily correct the performance limiting factors at several
plants. In the CCP approach, improved plant performance is achieved through
implementation of corrective actions recommended by a team of experts; based on
their comprehensive evaluation of a plant using the limiting performance
factors developed from the National O&M Cause and Effect Survey.
The corrective actions may include either improved manual or automated
process control or physical changes in the plant or collection system. Limiting
performance factors, where operator decision and measurement or control of
various process parameters play important roles, generally can be corrected by
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improved manual process control (operation) or by instrumentation and automation.
A review of the 10 major causative factors for poor plant performance reveals
that operator decision (performance, or understanding) plays or can play an
important role in five major factors (factors 1, 2, 4, 5, and 9) and the inability
or failure to measure or control various process parameters plays or can play
an important role in four major factors (factors 2, 3, 6, and 7).
Those performance limiting factors which involve major design deficiencies
or major plant inflexibilities usually can not be corrected by either manual or
automated process control and require physical changes in the plant or collection
system. Only four of the 10 major factors listed above (factors 3, 6, 8, 10)
can be addressed by making physical changes in the plant. Clearly, improved
process control, manually or automatically, is the more important area impacting
plant performance in municipal wastewater treatment.
PROCESS CONTROL IN INDUSTRY
In industry, process control is nearly synonymous with automation. The
use of automation and automated machinery for process control to improve
productivity and reliability is in such an accelerated state of development
that even the most visionary of our engineers and scientists may often
underestimate its potential. In just the past decade, automation has made it
possible to produce mechanical hands capable of picking up either eggs or lead
bricks without breaking or dropping either. These same hands can be directed
by other sensors to sort out flawed parts randomly scattered on a moving belt.
i
The oil industry'is automated from the well head through the refining
process to the station pump that shuts off when the tank is full, registers the
volume dispensed and calculates the cost to the customer. The chemical,
pulp and paper, steel and rubber industries are all automated. All of this has
occurred without federal funding, federal guidelines, or any other type of
federal provocation. In the water treatment industry the delivery of processed
water, while not as fully automated as the petrochemical industry, is evolving
into full automation. In the near future manual meter reading are likely to be
replaced by telemetered data.
These industries did not arrive at full automation in a single step, nor
was automation set as an ultimate goal. The present level of automation in any
industry is a result of careful analysis and refinement of multiple incremental
advances in the understanding of a specific part of a process and companion
advances in technology. Before any advances become state-of-the-art, three
things must occur. Firstly, an understanding of the problem is developed (often
through the use of automatic measuring techniques). Secondly, automated control
technology is applied to the problem. And thirdly, the solution is proven to
be cost effective.
The reading of water meters is an example of the incremental development
process. Processing,' transport, metering, billing, remote sensing and
telemetering, and the processing of remotely sensed data are all present state-
of-the-art. Recent improvement in the technology of data transmission combined
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with the impact of inflation on wages and energy costs have unbalanced the
existing cost benefit equation. When it becomes more profitable to read and
transmit water use data automatically, the final link .will be in place. The
market place will force implementation of this technology.
In process industries process control is not only extensively automated
but is rapidly shifting from analog to digital control. The shift to digital
occurs not only because of improved control with digital systems but, more
importantly, because it is more economical. The recent technical advances in
mini-computers and digital process controllers (micro-processor) have produced
major decreases in equipment costs per unit of control capacity. Thus, in the
classical control loop of sensor, controller, and actuator, a single inexpensive
digital process controller or moderately expensive mini-computer can replace,
respectively, a few or many analog controllers. In addition the digital process
controller or mini-computer permits an integrated or full systems control approach,
In contrast to industry, the extensive use of integrated and automated
system process control has not achieved a major market penetration in the
municipal wastewater treatment field. Before addressing the market for
integrated automated process control as a remedial approach to poor plant
performance in wastewater treatment, a brief summary of the state-of-the-art of
automated process control in the municipal wastewater treatment is needed.
AUTOMATION AND INSTRUMENTATION IN WASTEWATER TREATMENT
For the last ten yeaYs, classical process control theory and digital
automation equipment have'been fully capable of meeting the technical needs for
automation of wastewater treatment. With the recent technical and economic
improvements in digital process controllers, the capabilities of digital
automation equipment now easily exceeds the technical and economic requirements
for automation of even small wastewater treatment plants. Indeed process
controllers, available for 10 to 15 thousand dollars, contain sufficient control
capacity to operate a complete conventional wastewater treatment train exclusive
of solids dewatering. Control techniques for dewatering which are being developed
at Minneapolis-St. Paul (5), are complex and, in conjunction with other plant
control needs, require greater digital capacity than that in one current small
(10-15 thousand dollar) process controller.
While basic control theory and digital systems exceed the needs of
wastewater treatment, only in the last two years have sufficient sensors
(Table 1) which are satisfactory for wastewater process control become
available. These sensors from selected manufacturers perform well with
reasonable maintenance requirements in the municipal wastewater environment.
The sensors and the tested process control loops (Table 2) now permit first
generation integrated automation of treatment plants.
This first generation automation involves two general levels of process
control. The elementary level, is monitoring and programmed gap action (on-off
control) for equipment that does not permit throttling control. The higher
level is continuous proportional-integral-derivative control (PID) for continuous
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TABLE 1. SUITABLE MONITORING SENSORS
Sensor
TOC
CH4
Toxics
COD
co2
NOX
Halogenated
organics
ATP
Turbidity
Suspended solids
Flow
Specific Probes*
PH
D.O.
Type
continuous
continuous
continuous
discrete
continuous
continuous
continuous
discrete
continuous
continuous
continuous
continuous
continuous
continuous
Interfaced to
Method Microorocessor
U.V.
Thermoconducti vi ty
Aerobic respirometry
Colorimetric
Infrared or thermo-
conductivity
Colorimetric
Infrared
Spectrophotometri c
Light Scattering
Light Scattering
Magnetic, mechanical, sonic
NH4+, N03~, N02~, metals
Potentiometric
Galvanometric or
Amperometric
yes
yes
no
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
*In some applications, interferences prevent satisfactory use.
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TABLE 2. CONTROL LOOPS
Control Function
Control Types*
Microprocessor
Software
Fully Tested Loops
DO
Flow
Sludge Wasting
SRT
Average F/M
Thickening
pH (chemical feeds)
Chemical Feed
Chlorination
Purging (NHL stripping)
Pure 02 Feed
Wastewater Filtration
Carbon Adsorption
Developing Loops
Vacuum Filtration
Incinerator Control
Feedforward with PID, or GAP
Action Feedback
Throttling PID, or GAP Action
Throttling PID, or GAP Action
Continuous Programmed Wasting
Programmed GAP Action
Continuous Programmed Wasting
Programmed GAP Action
GAP Action
Feedforward with PID
Feedforward with PID
Feedforward with PID
Combined PID and GAP Action
Logic Network
Logic Network
Logic Network
Logic Network with PID
Feedback with PID
yes
yes
yes
**
yes
**
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
no
*PID is proportional integral-derivative control (feedback)
GAP action is on-off control (feedforward or feedback)
**AvaiTable on mini-computer, under development for microprocessor
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variable control of systems. With the proven sensors (Table 1) and tested
process control loops (Table 2), appropriate integrated and automated process
control approaches, especially using the micro-processor, can now be applied to
conventional wastewater treatment plants from the small ( 0.5 MGD) to the
largest plants. Cost benefit analyses (6, 7) have indicated a pay back period
for the tested control loops of typically 3-5 years.
The micro-processor represents a major advance in computer costs and
reliability for process monitoring and control that should not be ignored in
wastewater treatment. The recent literature (8) indicates significant
improvement in reliability of digital control (micro-processor) with the
appropriate sensors for wastewater applications. The micro-processor, itself,
exhibits significant advancement (9) in reliability when compared to analog and
logic network controller systems. Micro-processor systems with integrated
automated process control, however, have not been installed or tested for full
plant operation.
Deficiencies in Process Control
The principle deficiencies remaining in process control for conventional
municipal wastewater treatment occur in two areas:
o The flocculation/separation of solids in
biological systems.
o The conditioning of solids for efficient dewatering
in sludge processing.
Research,'as an example the "work by Jenkins (10) at the University of California,
has begun to assess the mechanisms and variables which control effective bio-
flocculation and solids separation in the activated sludge process. However
sufficient knowledge is not at hand to allow definitive process control. Until
.substantially all of the cause and effect variables are understood and become
controllable, changes in process conditions can cause population shifts or
"upsets" in the biota of the process degrading the flocculation or settling
characteristics of the biological mass. These changes will continue to
occassionally produce process failure, whether under efficient manual or
automated process control.
Similarly the interrelated mechanisms and variables controlling sludge
conditioning for dewatering are not completely defined. Thus the complex
process control approach for vacuum filtration (Table 2) under development at
Minneapolis-St. Paul, should improve the dewatering performance and prove cost
effective (savings in chemicals, etc.,) but may not insure the level of control
expected from the tested control loops of Table 2. In addition, the vacuum
filtration control approach may require substantial tuning for use at other
locations.
Deficiencies also exist in potentially desirable sensors. These sensors
(Table 3) fortunately are not essential for reasonable levels of automated
process control at conventional treatment plants. The most desirable are sensors
to measure changes in settleability and in dewaterability of solids. The current
measurements for settleability and dewaterability require discrete manual
procedures.
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TABLE 3. UNAVAILABLE ON-LINE SENSORS*
Sensor Function
Low chlorine residual (0.01 mg/1) Dechlorination
Real time settleability predictor** MLSS Separation
Filter cake moisture analyzer Dewatering
Improved filterability predictor** Vacuum filtration
Combustion analyzer Incineration
Ozone analyzer (in water) Disinfection
Viable coliform indicator Disinfection
* Sensors could improve present methods
of. control
** . Predictors probably require multiple
measurements with correlation equation
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Outputs from the Automation and Instrumentation Program
In September of 1974, the EPA conducted a workshop on "Research Needs
for Automation of Wastewater Treatment Systems." The principle technical
needs, as indicated by that workshop, and the MERL Automation and Instrumentation
(A&I) Program's remedial actions are shown in Table 4. These EPA's A&I technical
outputs (Table 4 and Appendix) have contributed significantly to the current
state-of-the-art in Automation. The on-going and recommended short term
program outputs listed elsewhere further address these needs.
IMPACT ON PLANT PERFORMANCE, COSTS, AND ENERGY
Before assessing the impact on automated process control on plant
performance, a perspective on current performance is needed. As documented by
several National studies (11, 12, 13) a significant portion of the existing
U.S. plants are not consistently meeting their NPDES requirements. Indeed the
GAO study (13) in 1977 revealed 40% of all treatment facilities failed to meet
design BOD removals and 49% failed to achieve design suspended solids removal.
MERL's National Operational and Maintenance Cause and Effect Survey (1,2,3) on
plants of 10 mgd and less documented even poorer performance of small treatment
plants. Of the 103 facilities evaluated, only 37 plants (36%) were consistently
meeting.their NPDES standards.
Proper process control (manual or automated) will improve plant performance.
Application of MERL's Composite Correction Program (CCP) (4) to several of the
plants in the MERL's Survey consistently revealed significant improved plant
performance. These manual process control practices in the CCP, at least for
activated sludge plants, are often substantially man-in-the-loop analog control
since the operators use information from instruments and sensors in the plant
to make the control decisions and implement their response. As a result of the
studies, it was further estimated that, by applying the CCP (good manual process
control), 86 percent of the plants could consistently achieve NPDES standards
with optional levels of performances without upgrading (i.e. designing and
improving) the facilities.
Over the years, practical pilot plant experience has revealed that good
manual control (usually man-in-the-loop analog) or automated control produced
similar process performance for conventional wastewater treatment plants. Such
manual operation involved continuous (24 hour) surveillance. In both control
approaches, good maintenance was required to insure consistent performance.
In evaluating the impact of automated process control on costs and energy,
existing municipal treatment plants may be divided into two significant groups,
suspended growth.(activated sludge) plants of 0.5 mgd or larger and all others
which principally include primary plants, small package plants, trickling filters
and lagoons. In this division, suspended growth plants of 0.5 mgd and larger
currently (1979 inventory) treat about 50 percent of the municipal wastewater
receiving the equivalent of secondary treatment and operator decision plays a
major role in the plant performance. In most of the other types of plants
(lagoon trickling filters ... etc.) operator decision plays a lesser role in
plant performance.
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TABLE 4. PRINCIPAL A&I PROGRAM OUTPUTS
Needs Area
Remedial Outputs
Publication Ref.
(Appendix A)
vo
Inadequate Instrument Reliability
(especially sensors)
Inadequate Sensors Support Equipment
Inadequate Development and Demonstration
of Process Control Loops
Inadequate Documentation of Automation
o Instrument Survey
o NBS Standards on Instruments
o Certification Laboratory for
Testing Instruments
A
o Wastewater Sample Transport
and Condition System
o Full Scale D.O. Control
o Control Strategies for Activated Sludge
o Physical-Chemical control Strategies
o Solids Processing Control Strategies
o State-of-the-Arts on Automation
o Design Manual on D.O. Control
o Design Manual on Automation
of Conventional Treatment Plants
o Cost Benefit Analysis
o Major Input to WPCF Manual of
Practice No. 21
22, 31
ongoing
initiated FY80
21
8, 24
9, 12, 13, 15, 30
10, 32
38, 40, 41, on-going
23, 27, 34
28
42 (in press)
26, 35
33
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The divison is not absolute since activated sludge plants, such as
extended aeration or "orbital" (race track) activated sludge plants with large
plant contact times, may not require extensive operator decision for successful
performance and some small package plants may require regular and substantial
operator decision for successful performance. The important reason for the
division, however, is that activated sludge plants of 0.5 mgd and larger
generally can benefically employ throttling (PID) control for several operations
or processes. (It should be noted that in-place equipment at many activated
sludge plants, unless modified, currently may only permit on-off control).
The other existing plants such as trickling filters and lagoons generally
do not significantly benefit from throttling control except where effluent
chlorination or mineral addition (phosphorus removal) is practiced. At such
plants, automated monitoring of effluent quality and equipment malfunction
represent the principal future uses of automated techniques. Such monitoring,
if used to initiate prompt plant maintenance, should improve plant performance
but not significantly reduce costs or energy requirements. For current practices
in municipal wastewater treatment, the chief difference between effective manual
and automated control occurs in the use of energy and chemicals. Since closed
loop (automated) control continuously evaluates and responds to diurnal loading,
it minimizes the use of energy and chemicals required to achieve desired performance.
While plants other than suspended growth (activated sludge plants) can,
on an individual plant basis show costs savings from automation, generally from
chemical savings (chlorine ormineral addition), an estimate on the potential
direct costs savings for wide.spread application of automation is developed
only for the suspended growth plants of 0.5 mgd and larger. These plants are
likely to represent the principal costs savings. In the analysis, the value of
improved plant performance is not included.
The cost analysis (Table 5) is for two types of control approaches,
centralized analog and centralized digital control. In the analyses the
conventional activated sludge plants for the 0.5 to 5 mgd plant sizes consisted
of conventional primary, conventional aeration, chlorination, gravity thickening,
digestion, and sand bed dewatering. The conventional activated sludge plants
above 5 mgd consisted of conventional primary, conventional aeration, chlorination,
gravity thickening, digestion, vacuum filtration and incineration.
The cost analysis was based on a present worth analysis of the treatment
plants for the two control options (central analog and central digital) and
produced the annual cost savings (14) for the addition of the analog or digital
automation to conventionally operated plants (manual or man-in-the-loop analog).
The present worth analysis accounted for the additional capital required for
the automation. The cost savings per plant used in Table 5 for the 0.5 to 1
mgd plants were not included in the published design handbook (14) because of
wide variability in the costs for these plant sizes. The cost savings for
these plant sizes, however, had been estimated during the preparation of the
design handbook. The costs are based upon a June 1978 base. Conversion to June
1980 would increase the amounts by approximately 15%. These cost estimates are
only for planning perspective since actual cost estimates are very site specific.
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TABLE 5. COST SAVINGS IN ACTIVATED SLUDGE TREATMENT
FROM
AUTOMATED PROCESS CONTROL*
Plant
Size
mgd
0.5-0.6
0.6-0.7
0.7-0.8
0.8-0.9
0.9-0.1
1-2
2-3
3-4
4-5
5-6
6-7
7-8
8-9
9-10
10-15
15-20
20-25
25-30
30-35
35-40
40-45
45-50
50-60
60-70
70-80
80-90
90-100
>100
No. of
Annual
Plants** 10J
85
70
52
47
51
262
107
69
39
28
29
21
13
20
41
25
15
6
4
4
6
2
5
4
4
1
2
16
1
1
1
1
1
1
2
2
2
2
3
4
O&M Costs Total Annual O&M
$/yr/plant
105
110
115
118
120
160
225
285
340
400
460
520
570
625
760
950
,120
,300
,450
,600
,750
,850
,100
,400
,650
,950
,200
,500
TOTALS 103 $/yr.
10"
8
7
5
5
6
41
24
19
13
11
13
10
7
12
31
23
16
7
5
' 6
10
3
10
9
10
2
6
72
406
$/yr.
,925
,700
,980
,664
,120
,920
,075
,666
,260
,200
;340
,920
,410
,500
,160
,750
,800
,800
,800
,400
,500
,700
,500
,600
,600
,950
,400
,000
,639
Savings/plant
103 $/yr.
Analog
15.5
16
16.5
17
17.5
18.5
20
21
22
23
24
25
27
28
35
52
70
88
105
125
145
160
185
200
215
230
240
375
Digital
13
14
14.5
15
15.5
19
25
30
34
37
36.5
36
35.5
35
45
65
87
110
130
155
180
200
230
260
280
310
370
550
Annual Savings
103 $/yr.
Anal og
1
1
4
2
1
1
1
1
6
32
,318
,120
858
816
893
,847
,140
,449
858
644
696
525
351
560
,435
,300
,050
528
420
500
870
320
925
800
860
230
480
,000
,793
Di
1
4
2
2
1
1
1
1
1
1
1
1
8
39
gital
,105
980
754
720
791
,978
,675
,070
,326
644
696
756
462
700
,845
,625
,305
660
520
620
,080
400
,150
,040
,120
310
740
,800
,872
* Based upon Design Handbook for Automation of Activated Sludge
Wastewater Treatment Plants (14); Cost Analyses for June 1978
** Municipal Inventory of Wastewater Treatment Facilities (1979).
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The cost analyses (Table 5) reveals an annual savings (1978 base) of
approximately 33 million dollars for centralized analog control and 40 million
dollars for central digital control for the 0.5 mgd and larger activated sludge
plants. These savings represent about an 8% savings for analog control and a
10% savings for digital control on the annual O&M costs of the activated sludge
plants (0.5 mgd and larger).
Total direct energy costs savings of between 10 to 15% were projected
for the cost analyses (14) in D.O. load following (10% savings on total plant
energy demand) and power demand control (5% savings on total plant energy
cost). The power demand control is practical only with the digital control
systems. Greater energy savings would require addition of power recovery
equipment such as gas turbines to use the methane generated at the treatment
plants. In this case automation should be employed to maximize the energy
recovery. Indirect energy savings also result from reduced (8%) chemical usage
such as in chlorination or in sludge conditioning.
A more speculative cost savings may develop with widespread application
of automation. Current O&M practices at large treatment plants use continuous
three shift operation to insure effective plant performance. The cost analysis
presented here represents conservative options where shift operating manpower
decreases and maintenance manpower increases with automation but the basic
three shift operations mode is retained. Long term experience with automation
may eventually lead to additional manpower savings through single shift operation
with only monitoring and emergency response on other shifts.
»
- MARKETING OF AUTOMATION
Automation of wastewater treatment plants has been recognized as candi-
date technology in the EPA's new Innovative and Alternative Technology Program.
With the existing sensors and digital equipment, integrated and automated
process control can better perform the same functions as the combinations of
manual, independent analog, and independent man in the loop process control
steps currently used in wastewater treatment systems. With proper systems
maintenance, as required for any successful process control approach (manual,
analog or integrated digital), the integrated digital process control will
minimize operator decision errors, and operator failures to make appropriate
control measurements. This should provide more reliable plant performance,
when compared to manual, independent analog, and man in the loop controls.
Granting the obvious impact of automation on other industries, why has
automation in the wastewater treatment industry not developed as rapidly?
Apparently the cost impetus although present, has been obscured by other
influences. In the municipal market the penalties for poor performance have in
the past been so low or non-existent that little incentive for maintaining
proper performance existed. Even now, this condition is only slowly changing.
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The literature (15, 16, 17) indicated several possible reasons for the
slow adoption of automation in wastewater treatment. The following reasons
were the most prominent:
o The portion of capital spent for automation is much smaller
in waste treatment plant construction than in other processing
industries. (3 to 5% vs. 8 to 15%), thus manufacturers do not
perceive a market.
o The technical skill required to maintain automated
equipment is not available at waste treatment plants.
o The waste treatment plant salary structure is insufficient
to attract qualified technical help.
o The quality of available automated equipment is
insufficient for the atmosphere of the wastewater
treatment plant.
o The frequency of maintenance required precludes the
successful operation of automated process control.
o Federal procurement regulations prevent the selection
of quality equipment on the open market.
All of the above statements are at least partially true. It is true
that the portion of funds,allocated to automation in the construction of a
wastewater treatment plant are less than that portion allocated by other
industries. There are, however, sound reasons for this allocation that have
little to do with the role or use of automation in wastewater treatment. For
instance, the cost of constructing an aeration basin and related piping for a
large activated sludge treatment plant is enormous when compared to the cost of
the few sensors, valves and controllers required to operate the process
effectively.
The installation of instrumentation and digital equipment for multiple
uses in large pl'ants is beginning to occur and has sufficient market value per
installation to encourage agressive marketing by the suppliers. The ISA Water
and Wastewater Industries Division has identified approximately 50 operating
plants, generally 10 MGD or above, with substantial automation. This will help
to accelerate automation in the larger plants. The 3-5% of total capital cost
is sufficient for large plants.
Unfortunately, for the small plant, 10 MGD and less, the needed digital
capacity, satisfied by low cost (10-20 thousand dollar) micro-processors and
(40-80 thousand dollar) mini-computers, does not involve on a per plant basis a
large market value. While the overall potential market is moderately large
(~ 20,000 plants), the low market value per plant for digital control, the
difficulties in entering a conservative market and the lack of proven per-
formance and cost effectiveness are likely to inhibit aggressive private
marketing.
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The second and third statements are interrelated. There is unfortunately
sufficient truth in these statements to retard adoption. This problem can only
be solved by time, aggressive recruiting, and training and by the use of the
operations contracts with progressive consulting firms (which will also prove
performance and cost effectiveness).
The last three statements are being addressed by the EPA and the field
and, as previously indicated, improvements have been achieved or remedial
efforts initiated. With out question it is a, "caveat emptor", market; there
are inferior products, that will require excessive maintenance, if indeed they
can be made to work at all. Too often competitive bids are evaluated by price
alone and product quality becomes secondary. When this occurs the chances of
purchasing inferior products are greatly enhanced. The direct impact of
inferior equipment on a user are readily apparent and costly.
It is the clear intent of federal procurement regulations that cost
criteria (low bid) only be applied after those bids that do not meet
specifications have been eliminated. The regulations do allow prequalification
of bidders, life cycle cost analysis, and performance standards, as well as
technical engineering specifications. Improvement of the specifications and
application of prequalifications, on-going tasks of the current EPA program,
will help to reduce the problem.
The most important missing outputs to help accelerate the market
acceptance, however, are:
o Documentation of proven overall plant performance
for digital automation of municipal plants.
o Technology transfer and training on existing state-
of-the-art.
In 1975 a grant with the Metropolitan Waste Control Commission was
initiated to document cost effective state-of-the-art automation of a large
conventional treatment plant. Reasonably reliable strategies were already
available for the liquid train, however, significant process control
development was required in the solids processing train.
The sludge handling control strategy work was initiated at an
existing commission plant. This development work did not progress as rapidly
as originally projected because viable control strategies for the chemical
conditioning and vacuum filtration processes were non-existent. Various
control strategies were developed and tested. Some of the strategies were
unsuccessful and sensors for other strategies were not available or required
improvement. Despite these difficulties it appears that by the end of FY80
coordinated on-line control of the ultimate disposal line (thickening, chemical
conditioning, vacuum filtration, and incineration) will be in place and
demonstrated. A digital computer will perform on-line optimization of the
solids processing line to maintain chemical, fuel, and manpower costs at a
minimum. Data to date indicates savings of at least 25% in chemical
conditioning costs.
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The anticipated demonstration of liquid and solid handling using
automation could not, however, be started under this grant. Construction
delays on the new plant caused by various factors, including contractor suits
and adverse regulatory commission rulings, made it clear that construction
would not be complete before 1984. Minneapolis-St. Paul is still committed to
full automation of the new plant. It is an option to the A&I program to
institute a new grant after the new plant is completed.
RESEARCH AREAS
In addition to the documentation and technology transfer areas the A&I
strategy will include research into:
o Process control strategies for new process
o Process control strategies for energy conservation
o Centralized management and operation of multiple
small plants
o Integrated control of wastewater systems
(plant and collection systems)
Automated control strategies for new processes such as; deep shaft, reactor-
clarifier systems with external 63 dissolution and, fluidized bed biological
treatment (both aerobic and anaerobic) should be developed as early as
possible. Early consideration of automated process control for new processes
will insure proper documentation of the treatment system and efficient process
operation.
In energy conservation, Dr. Richard Stone of Brown and Caldwell has
stated "that between 50 and 60 percent of the energy demand of conventional
municipal treatment can be eliminated by integrating efficient energy usage
into conventional plant design." "Integrated" plant design includes process
and energy recovery equipment that can be efficiently operated with conventional
controls. Further, G.L. Funk (18) indicates that "as processes become more and
more integrated with respect to energy usages and generation, automation and
closed loop control become increasingly significant and essential." Retrofit -
methods for effective energy utilization at existing plants will require
further R&D.
Centralized management and operation of small plants is likely to be the
most cost effective mechanism for providing effective operation and maintenance
(skilled professionals and technicians) to the small plants. The development
of micro-processor and mini-computer systems in monitoring, process control,
and remote data transmission are essential for efficient centralized management
of operations and maintenance.
The use of computers to reduce combined sewer overflows has been
successfully applied in Seattle, Washington (19). With the accelerating
improvements in costs and capabilities of computer systems, development of
automated area wide management systems employing integrated digital control
-15-
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offers potential for improved management of municipal treatment systems (plants
and collection systems). The potential impact of the demand for automated area
wide management systems for municipal wastewater treatment, including
monitoring of toxics inputs or spills, should at least be evaluated as a desk
top analysis for guidance to the operating programs and to identify specific
research needs.
RECOMMENDED STRATEGY
A recommended strategy to accelerate improvements in plant performance
using automated process control in municipal wastewater treatment is presented
here as a comprehensive approach. Recognizing that competing priorities limit
resources, the strategy is divided into short and longer range objectives with
individual objectives within the two output groups prioritized as to timing
requirements and importance of projected impact. Thus, the strategy attempts
to provide maximum benefit at whatever level of available resources.
The strategy by objective is briefly summarized below in prioritized
rank:
Short Range Objectives: •
1. Transfer state-of-the-art, demonstrate and document
integrated microprocessor control of small plants and
document design approaches on available automation for
energy conservation.
a. Transfer present SOA technology to the field
so that the cost effective instrumentation
and automation presently proven feasible is
appreciated, understood and properly applied.
b. Demonstrate and document integrated micro-processor
control of small treatment plants.
c. Document design approaches for use of automation
and instrumentation for energy conservation.
2. Develop centralized management of multiple small plants
using digital technology.
3. Document benefits of overall plant automation.
Long Range Objectives
o Develop improved automated approaches to achieve energy
conservation.
-16-
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o Develop'automated process control for new technology and
improved approaches on existing technology.
o Develop automated areawide management for plants and
collection systems.
o Support, as needed, the continuing development of
instrument specifications (NBS) and the establishment
of the non-Federal instrument certification laboratory.
The specific outputs with estimated resources to achieve the short range
objectives are presented in Table 6. The Table includes a summary of the on-
going outputs from the current A&I program. A review of these outputs reveals
that the ongoing tasks provide previously missing control strategies or models
(solids processing, anaerobic digestion), support the need for improved
equipment selection (NBS specifications, Instrument Certification Laboratory)
or support the above strategy objectives.
Three needs are included in the first priority short range objectives.
Our recent (in press) design manual on tested control strategies, the D.O.
control design manual, and selected outputs from our completed (Appendix A) and
on-going work provide the state-of-the-art for transfer to the field. The
large number of small plants with poor performance compels a high priority for
improving control at small plants. Finally the potential reduction in energy
and chemical usage using automation to minimize fuel consumption and operating
costs completes the high priority objective.
The four outputs (Table 6) to meet the first priority objectives require
modest funding of 550K over two fiscal years. The development of the micro-
processor control for small plants, shown with two levels of control could be
strengthened by testing each control level at more than one type of conventional
plant. The micro-processor control projects, (implemented through cooperative
agreement) in the first priority level of the program would feature a CCP
approach. This project will provide examples of a plant management approach to
provide the knowledge of a highly trained engineer (programmed into the micro-
processor) at a small treatment plant. The on-site personnel would be trained
to maintain and operate the sensors and micro-processor.
Successful process control requires proper maintenance and knowledgeable
personnel. With automation, routine operator decisions are less critical but
effective routine maintenance and the availability of competent personnel for
operating emergencies are needed. To insure such competency at small plants,
the implementation of the micro-processor control projects would be achieved
through the use of private consulting firms which have an interest in operating
treatment plants as an offered service.
The demonstration of micro-processor control would further serve as the
nucleus for the second priority objectives of centralized management of
multiple small plants. In the output for this objective, the micro-processor
control systems of. the above tasks would provide the automated monitoring and
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TABLE 6. SUGGESTED SHORT RANGE OUTPUTS
00
I
In
1.
2.
3.
4.
5.
6.
Output
Description
Progress *
Develop and demonstrate Cost Effective Sludge
Processing Automation & Instrumentation
Evaluate new concepts in 0 & M using coordinated
manual and computer techniques (man in the loop)
Develop time dependent model of Anaerobic Digestion
Evaluate remote monitoring to reduce 0 & M costs
of small remote plants
Develop Instrument Testing; Installation and Maintenance
Procedures and Specifications
Establish Organizational and Administrative Structure
for Non-Federal Instrumentation Certification
Laboratory
Funding
Fully
Funded
Fully
Funded
Fully
Funded
Fully
Funded
Fully
Funded
Fully
Funded
Delivered
Output
FY80
FY80
FY81
FY80
FY81
FY82
(continued)
-------
TABLE 6. SUGGESTED SHORT RANGE OUTPUTS (cont'd.)
Fi
7.
8.
9.
10.
Output
Description
rst Priority New Tasks
Develop and Present Technology Transfer Seminars
for Design Consultants, Regional Officers and
Corps of Engineer Professionals *
Develop and Demonstrate Integrated Microprocessor
Control of Small Conventional Plants
2 levels on-off gap action
continuous PID control
Prepare Training Course for Plant Operators
in Automation & Instrumentation
Prepare Design Manual on Use of Automation
and Instrumentation for Energy Savings
Funding
FY81
100K
FY81-82
150K
150K
FY81
50K
FY82
100K
Delivered
Output
FY81
FY83
FY82
FY83
Second Priority
11.
Develop and Demonstrate Centralized Management
of Multiple Small Plants Using Digital
Automation
FY82-83
200K
FY83
Third Priority
12.
13.
Perform Survey and Market Study of Automation and
Instrumentation in Water Pollution Control
Industry (Municipal and Industrial)
Document Performance and Benefits of Automation
at Large Plants
FY81
200K
FY82
100K
FY83
FY83
-------
transmission of selected data from remote plants to a mini-computer at a
central support site. The centralized management approach for multiple plants
would economically permit the assembly of a competent staff to provide the
needed routine maintenance and emergency O&M of the process and process control
equipment, and also provide the continuous surveillance that produces effective
plant performance in well run large treatment plants.
The third priority in the short range outputs, the documentation of
benefits of plant automation, is addressed by two tasks. The survey and market
study of A&I in water pollution control performs two important functions:
o Provides a linkage between municipal and industrial
wastewater treatment process control advances and
markets (jointly performed by MERL and IERL).
o Provides needed guidance on future automation and
process control both for ORD and the operating programs.
The last task, the documentation of the benefits of automation at large plants,
completes the overall assessment of first generation automation in municipal
wastewater treatment.
These short range objectives are the culmination of MERL's existing
Automation and Instrumentation Program. The outputs from these objectives as
remedial solutions to problems provide the first generation automation products
and support their transfer to the field. These outputs should accelerate the
use of modern automated process control to achieve improved plant performance
in municipal wastewatec treatment at"only very modest R&D costs, and, more
importantly, provide improved process control for the full range of plant sizes
in the municipal field at minimum capital costs to the municipalities. As an
example, the programmed micro-processor at 10-15 thousand dollars for small
plants, mini-computers at 40-80 thousand dollars for the larger plants and
sensors at less than 50 thousand dollars per treatment train would constitute .
the principal capital investment per plant. Indeed, many of the sensors may
already be in the treatment plants.
With a technical field as progressive and innovative as the digital
computer field, the potential for continuing benefits to process control and
wastewater treatment should not be ignored by the Agency's R&D effort. Thus
the proposed long range objectives for automation and instrumentation represent
the more important areas where substantial benefit can occur. The specific
output tasks (Table 7) associated with the longer range objectives also
represent the "best estimates" for future work. These tasks will be modified
as appropriate from evaluation of the on-going short range outputs.
As with the on-going A&I program, the suggested short and long range
tasks cross various Decision Unit areas within MERL. The past work and the
short range objectives are specifically related to MERL's Plant Design and
Reliability areas. The long range tasks also impact significantly New Process
Development (which supports the Agency's Innovative and Alternative Program)
the Ultimate Disposal area, the Energy Conservation effort and the Urban Runoff
Program.
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TABLE 7. SUGGESTED LONG-RANGE OUTPUTS
Output Description
Funding
Delivered
Output
Energy
Automation of Anaerobic Wastewater
Treatment
On-Line Computer Optimization of
Complex Treatment Plants
Applicability of "Artificial Intelligence"
Computer Systems to Optimize Operations
at Treatment Plants
Improvements in Treatment Process and Process
Control
Automation of New Liquid Treatment Control
Strategies
Automation of New Ultimate Disposal Control
Strategies
Area Wide Management
Remote Sensors in Sewers for Enforcement
and Treatment Plant Protection
Area Wide Control of Pollution and Water
Quality
Improved Reliability through Equipment Selection
Support for Specifications Development and
Instrumentation Certification Laboratory
FY-82
150K
FY-82
175K
FY-82
75K
FY-82-85
50-75K
per year
FY-82-85
50-75K
per year
FY-82-83
100K
FY-82-85
250K
FY-82-85
110K
per year
FY-83
FY-84
FY-84
FY-84-85
FY-84-85
FY-84
FY-85
On-going
Outputs
-21-
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The A&I work on new process control strategies thus relies on definition
of the pertinent process control mechanisms by the Treatment Brocess Development
and Sludge Management Programs. Indeed such definition may require automated
data acquisition. Similar interactions occur with the Energy Conservation
and Urban Runoff Programs. Development of new automated process control
strategies for process control or energy conservation and areawide management
techniques should be in partnership with the appropriate wastewater treatment
program.
The A&I program, as part of the Wastewater Research Division's
Technology Development Support function, provides both the skilled professional
support with "hands on" experience and facilities with the necessary equipment.
A distributed digital control research tool is now being installed at the
Test and Evaluation Facility to support the research projects at the Facility.
These resources, thus, permit efficient development of proposed Automation
and Instrumentation strategies. In short, the A&I activity should be
considered primarily as a technology support function. The prime customers
being the other MERL programs with needs for assistance in establishing cost
effective real time control and monitoring of processes and systems.
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REFERENCES
1. Hegg, B.A., Rakness, K.L., Schultz, J.R., "Evaluation of Operation and
Maintenance Factors Limiting Municipal Wastewater Treatment Plant
Performance." Environ. Protection Techno!. Series, EPA-600/2-79-034.
2. Gray, A.C., Jr., Paul, P.E., Roberts, H.D., "Evaluation of Operation
and Maintenance Factors Limiting Biological Wastewater Treatment Plant
Performance." Environ. Protection Techno!. Series, EPA-600/2-79-078.
3. Hegg, B.A., Rakness, K.L., Schultz, J.R., "Evaluation of Operation
and Maintenance Factors Limiting Biological Wastewater Treatment Plant
Performance Phase II." In Print.
4. Hegg, B.A., Rakness, K.L., Schultz, J.R., "A Demonstrated Approach for
Improving Performance and Reliability of Biological Wastewater Treatment
Plants." Environ. Protection Technol. Series, EPA-600/2-7.9-035.
5. Kugelman, I.J., et a!., "Instrumentation and Automated Control of
Municipal Sludge Treatment Facilities," Proceedings of the seventh
U.S.-Japan Conference on Sewage Treatment Technology, May 1980.
Tokyo, Japan.
6. Molvar, A.J., J.F. Roesler, R.H. Wise and R.H. Babcock, "How
Reliable is Instrumentation in Wastewater Applications?" Instruments
and Control Systems, 50, 10 29 (1977).
7. Molvar, A.E., J.F.'Roesler, R.H. Wise, and R.H. Babcock, "Wastewater
Plants Use Less Instrumentation than Related Industries." Water
and Wastes Engr., 58 (April 1977).
8. Jutila, J.M., "Computers in Wastewater Treatment: Opportunities
Down the Drain." Intech, 26 19 (1979).
9. Microprocessor Based Systems Expand Process Monitoring and Control
Capabilities," Computer Design, ^8, 55 (1979).
10. Jenkins, D., Grant-No. R-806107, "Investigation of Factors Effecting
Bulking of Activated Sludge," Municipal Environmental Research
Laboratory, U.S. EPA, Cincinnati, OH. Work on-going.
11. U.S. EPA, "Clean Water Report to Congress," Washington, D.C. 1974.
12. U.S. EPA, "Clean Water Report to Congress," Washington, D.C. 1975-1976.
13. Comptroller General of the United States, "Continuing Need for Operation
and Maintenance Factors Limiting Municipal Wastewater Treatment Plant
Performance." Report to Congress, Washington, D.C., CED-77-46, April
1977.
14. Manning, A. W. and Dobs, D. M., "Design Handbook for Automation of
Activated Sludge Wastewater Treatment Plants," EPA 600/8-80-028,
Municipal Environmental Research Laboratory, Cincinnati, OH (in press).
-23-
(rev. 8/20/80)
-------
15. Roesler, J.F., "Status of Instrumentation and Automation for Control
of Wastewater Treatment Plants," Proceedings of the Fourth U.S.-Japan
Conference on Sewage Treatment Technology, Cincinnati, OH, 598,
October 28-29, 1975 (1976).
16. "Research Needs for Automation of Wastewater Treatment Systems" Workshop
Proceedings, 23-25 September 1974, Editors: H.O. Buhr, J. F. Andrews and
T. M. Keinath, Clemson University, Clemson, South Carolina (June 1975).
17. Molvar, A. E., J. F. Roesler, R. H. Wise, and R. Babcock, "Instrumentation
and Automation Experiences in Water Treatment Facilities," Environ.
Protection Technology Series, EPA-600/2-76-198 (January 1977).
18. Funk, G.L., "Automation Turns Energy Conservation Theory into Reality."
Chem. Engr. Progress, _76, No. 4, p. 46, (April 1980).
19. Leiser, C.P., "Computer Management of a Combined Sewer System.",
EPA-670/2-74-022, Municipal Environmental Research Laboratory,
U.S. EPA, Cincinnati, Ohio, July 1974.
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APPENDIX A
Instrumentation and Automation Program
List of Publications
1. Convery, O.J., Roesler, J.F., and Wise, R.H., "Automation and
Control of Physical-Chemical Treatment for Municipal Wastewater,"
Applications of New Concepts of Physical-Chemical Wastewater
Treatment, Sept. 18-22. 1972. Pergamon Press Inc., USA.
2. Roesler, J.F., "Factors to Consider in the Evaluation of Alternate
Control Strategies," Proceedings of the Second U.S.-Japan Conference
on Sewage Treatment Technology, December 1-6, 1972, Cincinnati, OH.
3. Molvar, A.E., and Roesler, J.F., "Selected Abstracts for
Instrumentation and Automation of Wastewater Treatment Facilities,"
Natl. Tech. Info. Serv. No. PB-225, 520/6 (1973).
4. Roesler, J.F., and Wise, R.H., "Variables to be Measured in
Wastewater Treatment Plant Monitoring and Control," Jour. Water
Poll. Control Fed., 46, 1979 (1974).
5. Smith, R., "The Use of Computers for Monitoring, Control and
Simulation of Wastewater Treatment Systems," Presented at the 7th
International Conference on Water Pollution Research, Paris,
Sept. 9-13, 1974". Proceedings published by Pergamon Press Ltd.
6. Wise, R.H., "Off-the-Shelf' Analyzers for Measuring Adenosine
Triphosphate (ATP) in Activated Sludge," Natl. Tech. Info. Serv.
No. PB-231 345/AS (April 1974).
7. Wise, R.H., "On-Line Colorimetric Analyzers for Monitoring Nitrate-
Nitrite Ammonia, Orthophosphorus, and Total Hydrolyzable Phosphorus
in Wastewater-Treatment Process Streams," Natl. Tech. Info. Serv.
No. PB-231 990/AS (June 1974).
8. Roesler, J.F., "Plant Performance Using Dissolved Oxygen Control,"
Jour. Environ. Eng. Div. Proc. Amer. Soc. Civil Engr., 100, 1069
(1974).
9. Stepner, D.E., and Petersack, J.F., "Data Management and Computerized
Control of Secondary Wastewater Treatment Plant," p. 417, Instrumentation
Control and Automation for Wastewater Treatment Systems: Progress in
Water Technology Vol. 6, Editors, J.F. Andrews, R. Briggs and S.H.
Jenkins, Pergamon Press, Oxford, England (1974).
10. Bishop, D.F. et al., "Physical-Chemical Wastewater Treatment and
Digital Computer Control, p. 533, Instrumentation Control and
Automation for Wastewater treatment systems: Progress in Water
Technology Vol. 6, Editors, J.F. Andrews, R. Briggs and S.H. Jenkins,
Pergamon Press, Oxford England (1974).
-25-
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11. "Demonstration of Digital Computer Application in a Wastewater
Treatment Plant," Publication No. 55, California State Water
Resources Control Board (July 1974).
12. Smith, R., and Eilers, R.G., "Control Schemes for the Activated
Sludge Process," Environ. Protection Technol. Ser., EPA-670/2-78-
069 (August 1974).
13. Petersack, J.F., and Smith, R.G., "Advanced Automatic Control
Strategies for the Activated Sludge Treatment Process," Environ.
Protection Technol. Ser., EPA-670/2-75-039 (May 1975).
14. "Research Needs for Automation of Wastewater Treatment Systems,"
Workshop Proceedings, 23-25 September 1974, Editors: H.O. Buhr,
J.F. Andrews and T.M. Keinath, Clemson University, Clemson, South
Caroline (June 1975).
15. Nagel, C.A., "State of the Technology: Semi-Automatic Control of
Activated Sludge Treatment Plants," Environ. Protection Technol.
Series, EPA-600/2-75-058 (December 1975).
16. Roesler, J.F. and Wise, R.H., "Annual Review of the Literature
in Instrumentation and Automation of Wastewater Collection and
Treatment Systems," Journ. Water Poll. Control Fed., 47, 1369
(1975).
17. Roesler, J.F., "Status of Instrumentation and Automation for Control
of Wastewater Treatment Plants," Proceedings of the Fourth U.S.-
Japan Conference on Sewage Treatment Technology, Cincinnati, Ohio,
598, October 28-29, 1975 (1976).
18. Wise, R.H., Roesler, J.F., and Kugelman, I.J., "Annual Review
of the Literature in Instrumentation and Automation of Wastewater
Collection and Treatment Systems," Jour. Water Poll. Control Fed.,
48,_ 1206 (1976).
19. Roesler, J.F., and R.H. Wise, "Annual Review of Instrumentation
and Automation of Wastewater Treatment Systems," Jour. Water Poll.
Control Fed. 47, 1369 (1975).
20. Wise, R.H., Roesler, J.F., and Kugelman, I.J., "Annual Review of
Instrumentation and Automation of Wastewater Treatment Systems,"
Jour. Water Poll. Control Fed., 48, 1206 (1976).
21. DiCola, L., "Wastewater Sample Transport-and Conditioning System,"
Environ. Protection Technol. Series, EPA-600/2-76-146 (Oct. 1976).
22. Molvar, A.E., J.F. Roesler, R.H. Wise, and R. Babcock, "Instrumentation
and Automation Experiences in Wastewater Treatment Facilities."
Environ. Protection Technology Series, EPA-600/2-76-198 (January 1977).
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23. Roesler, J.F., D.F. Bishop, and I.J. Kugelman, "Current Status
of Research in Automation in Wastewater Treatment in the United
States," Prog. Wat. Tech., £, 659, Pergaman Press, (1977).
24. Flanagan, M.M., B.D. Bracken, and J.F. Roesler, "Automatic
Dissolved Oxygen Control," Jour. Environ. Eng. Div. Proc. Amer.
Soc. Civil Engr., 103, 707 (1977).
25. Roesler, J.F., "The State-of-the-Art for the Automation of
Sludge Handling Processes," Proceedings of the Third National
Conference on Sludge Management, Disposal and Utilization, Miami,
FL., December 14-16, 1976, 173 (1977)..
26. Molvar, A.J., "Selected Applications of Instrumentation and
Automation in Wastewater-Treatment Facilities," Environmental
Protection Technology Series, EPA-600/276-276, (February 1977).
27. Molvar, A.E., J.F. Roesler, R.H. Wise, and R.H. Babcock, "Waste-
water Plants Use Less Instrumentation than Related Industries."
Water and Wastes Engr., 58 (April 1977).
28. Flanagan, M.J., and B.D. Bracken,."Design Procedures for Dissolved
Oxygen Control of Activated Sludge Processes," Environ. Protection
Techno!. Ser., EPA-600/2-77-032, (June 1977).
29. Roesler, J.F., Kugelman, I.J., Cummins, M.D., "Annual Review of
the Literature in Instrumentation and Automation of Wastewater
Collection and Treatment Systems," Jour. Water Poll. Control Fed.,
49, 1104 (1977)'.
30. Ortman, C., T. Laib and C.S. Zickefoose, "TOC, ATP and Respiration
Rate as Control Parameters for the Activated Sludge Process,"
Environ. Protection Techno!. Series, EPA-600/2-77-142 (September
1977).
31. Molvar, A.J., J.F. Roesler, R.H. Wise, and R.H. Babcock, "How
Reliable is Instrumentaiton in Wastewater Applications?" Instruments
and Control Systems, 50, 10, 29 (1977).
32. Yarrington, R., W.W. Schuk, and J.E. Bowers, "Digital Control of
Advanced Waste Treatment Systems," Environ. Protection Technol.
Ser., EPA, EPA-600/2-77-211 (1977).
33. Arthur, R.M. Ed., "Instrumentation in Wastewater Treatment Plants,"
Manual of Practice No. 21, Water Poll. Control Fed. (1977).
34. Genthe, W.K., J.F. Roesler and B.D. Bracken, "Case Histories of
Automatic Control of Dissolved Oxygen," Jour. Water Poll. Control
Fed. 50, 2257 (1978).
35. Roesler, J.F., R. Timmons and A. Manning, "A Cost/Benefit Analysis
for Automation of Wastewater Treatment Plants," Prog. Wat. Tech.,
9, 369 (1978).
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36. Roesler, J.F. and M.D. Cummins, "Annual Review of the Literature
in Instrumentation and Automation of Wastewater Collection and
Treatment Systems," Jour. Water Poll. Control Fed. 50, 1185 (1978).
37. Kugelman, I.J., M.D. Cummins, W.W. Schuk, and J.F. Roesler,.
"Progress in Instrumentation and Automation," Proceedings of the
Sixth U.S.-Japan Conference on Sewage Treatment Technology,
October 28-31, 1978, Cincinnati, OH.
38. Rice, R.E., and G.A. Mathes, "Direct Digital Control of a Vacuum
Filter—Part II," Advan. in Instru., _33, 3, 79 (1978).
39. Cummins, M.D., I.J. Kugelman, A.C. Petrasek, Jr., J.F. Roesler,
and W.W. Schuk, "Annual Review of the Literature in Instrumentation
and Automation of Wastewater Collection and Treatment Systems,"
Jour. Water Poll. Control Fed., 51, 1294 (1979).
40. Polta, R.C. and Stulc, D.A., "Automatic Sludge Blanket Control
In An Operating Gravity Thickener," EPA-600/2-79-159, Municipal
Environmental Research Laboratory, Cincinnati, OH, (Nov. 1979).
41. Kugelman, I.J., et al., "Instrumentation and Automated Control
of Municipal Sludge Treatment Facilities," Proceedings of the
Seventh U.S.-Japan Conference on Sewage Treatment Technology,
May 1980, Tokyo, Japan.
42. Manning, A.W., and Dobs, D.M., "Design Handbook for Automation of
Activated Sludge Wastewater Treatment Plants." EPA-600/8-80-028,
Municipal Environmental Research Laboratory, Cincinnati, OH.
(In Press).
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APPENDIX B
Description of Suggested Short Range Outputs
(In Progress)
1. Develop and Demonstrate Cost Effective Sludge Processing Automation
and Instrumentation
Output and Benefits - Demonstration of computer control and on-line
economic optimization of gravity thickening, chemical conditioning,
vacuum filtration and incineration. Will have national impact on
economics and energy use in sludge processing.
2. Evaluate New Concepts in O&M Using Coordinated Manual and Computer
Techniques (Man in the LoopT
Output and Benefits - Evaluation of improved and more economical
operation and maintenance by use of operator controlled CRT display
of plant operational data, performance trends, maintenance records,
parts inventory, and equipment status. Will have national impact
on operation and maintenance costs and reliability.
3. Develop Time Dependent Model of Anaerobic Digestion
Output and Benefits - The model will allow more efficient operation
at higher loadings with lower failure possibility. Potential for
higher methane per unit volume. Will impact both the future design
of, and the present operation of anaerobic digesters.
4. Evaluate Remote Monitoring to Reduce O&M Costs of Small Remote Plants
Output and Benefits - Will illustrate minimum cost and maximum
reliability of remote monitoring system for operation and maintenance
of a network of small-remote treatment plants and sewage pumping
units. Precursor of area-wide control of drainage basin water quality.
Will have national impact on economics and reliability of small,
remote treatment units.
5. Develop Instrument Testing, Installation, and Maintenance Procedures
Output and Benefits - Will provide rules, specifications and guidelines
on field procedures for evaluation of applicability of an instrument
for wastewater applications. Will have impact on construction grant
funding rules, plant reliability, and instrumentation cost. Availability
of reports at approximately 6 months starting in the last quarter of
FY80.
6. Establish Organizational and Administrative Structure for Non-Federal
Instrumentation Certification Laboratory
Outputs and Benefits - Will provide an independent organization for
certification of performance of instrumentation which will provide
the mechanism for keeping substandard equipment from the marketplace.
Potential construction cost savings of several million dollars annually.
Available first quarter FY82.
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(First Priority New Tasks)
7. Develop and Present Technology Transfer Seminars for Design Consultants,
Regional Offices and Corp. of Engineer Professionals
Output and Benefits - This program would place the output of on-going
work with NBS in the field quickly and prevent improper installation
problems referenced by the CCP program.
8. Develop and Demonstrate Integrated Micro-processor Control of Small
Conventional Plants
Output and Benefits - This project will illustrate that a conventional
treatment plant's performance can be significantly improved in a cost
effective manner. The routine operations such as monitoring and
control of dissolved oxygen pump operation, tank level, flow splitting,
sludge collection and pumping, etc., will be handled 24 hours per day
by a preprogrammed micro-processor. This will free the operator to
concentrate on equipment and sensor maintenance. The operator will
not be required to make process control judgments.
9. Prepare Training Course for Plant Operators in Automation and
Instrumentation
Output and Benefits - Will provide training in instrumentation
maintenance, use of programmable calculators to make process control
decisions and elementary computer-operator interactions for plant
operation and maintenance record keeping. This will result in
dissemination of. new operation and maintenance techniques to the field.
This project will be conducted in cooperation with National Training
Center. Available in FY82.
10. Prepare Design Manual on Use of Automation and Instrumentation for
Energy Savings
Output and Benefits - This manual will be useful to designers and
operators (owners) of treatment systems as a guide to saving energy
and chemicals and consequently power and fuel costs. The manual will
address new designs, the retrofit of old plants, and changes in present
operational procedures. Included will be discussions of new technology
such as new methods of motor speed control of pumps and blowers,
turbines which can burn low BTU gas, and heat pumps for energy recovery
from sewage. Potential impact on treatment energy requirements
and economics.
(Second Priority)
11. Develop and Demonstrate Centralized Management of Multiple Small Plants
Using Micro-processor Automation
Output and Benefits - Will document the impact of centralized management
on the operating cost and reliability of small treatment plants.
Precursor of centralized control of drainage basin water quality. Will
have national impact on the economics and reliability of area-wide basin
management systems.
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(Third Priority)
12. Perform Survey and Market Study of Automation and Instrumentation in
the Water Pollution Control Industry (Municipal and Industrial )T
Output and Benefits - Access the potential impact of instrumentation
and automation on the combined municipal and industrial wastewater
treatment field. This work will provide background and guidelines
to aid in determining national research needs.
13. Document Performance and Benefits of Automation at Large Plants.
Output and Benefits - Provide a data base for cost benefit analysis
of automation in large wastewater treatment plants. Such information
is necessary for the promulgation of national guidelines for
construction grant applications involving automation.
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Description of Suggested Long Range Output
1. Automation of Anaerobic Wastewater Treatment
This component of the A&I program will develop and demonstrate control
strategies for the anaerobic expanded bed biological contactor for
wastewater treatment. This process has the potential to provide a
net energy production. Control strategies that will be considered
will be bed expansion control, recycle control, pH control, etc.
Output and Benefit - Final report documenting the energy inputs and
outputs of the process and the process controls required to stabilize
the process.
2. On-line Computer Optimization of Complex Treatment Plants.
This is applicable to a treatment plant which has alternative methods
of achieving the output goal. For example, use of more coagulants
prior to sedimentation versus shorter filter runs or lower filtration
rates. The computer will analyze the available data on the treatment
process performance, construct models of each process and synthesize
these into an overall systems control model based on least cost.
Output and Benefit - Applicable to performance optimization of large
(greater than 10 MGD) or complex treatment plants.
3. Applicability of Artifical Intelligence Computer Systems to Optimize
Operation of Treatment Plants
This will evaluate the use of artifical intelligent computer systems
in operation and maintenance of POTW. These systems have the ability
-to learn by experience. Thus, the computer system can gradually learn
how to best operate a treatment plant.
Output and Benefit - This type of computer system is the easiest for a
plant operator to adapt to and is potentially the most cost effective
for operation and maintenance.
4. Automation of New Liquid Treatment Control Strategies.
The development of new innovative liquid treatment processes by other
EPA programs will require control strategy development and evaluation.
This component of the A&I program will develop, evaluate, and demonstrate
new processes.
Output and Benefit - Produce reports detailing cost effective strategies
and detailing techniques for applying them. This work will be done in
partnership with TPDB.
5. Automation of New Ultimate Disposal Control Strategies
The development of new innovative ultimate disposal process by other
EPA programs will require control strategy development and evaluation.
This component of the A&I program will develop, evaluate, and demonstrate
new processes.
Output and Benefit - Periodic reports detailing cost effective strategies
and detailing techniques for applying them. This work will be done in
partnership with TPDB.
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6. Remote Sensors in Sewers for Enforcement and Treatment Plant
Protection
The use of remote sensors in sewer systems to pick up discharges of
unusual, toxic, regulated, etc., wastes will aid enforcement and
protect treatment plants from upset.
Output and Benefit - Periodic reports on demonstrations, sensor cost,
maintenance, and experienced results.
7. Area Hide Control of Pollution and Water Quality
This component of the A&I program will demonstrate area wide control
of a network of treatment plants to insure optimum performance and
water quality. This will involve both large and small plants in a
river basin. Both remote monitoring with reporting to a centralized
computer and on site process control computers will be used in an
appropriate mix. The central management site will make the management
decision as to how each plant is to be run so that water quality
criteria in the drainage basin is met as the load shifts between plants.
Output and Benefits - Most cost effective control of water quality
over a wide area. Each treatment plant will be adjusted to perform
only that function necessary to meet local and regional goals.
8. Support for Specifications Development and Instrumentation Certification
Laboratory
This component of the A&I program will provide continuing support for
developing instrument testing procedures and establish a non-federal
organization for" certification of wastewater treatment instrumentation.
This will prevent sub-standard equipment from reaching the market place
and installation in wastewater treatment plants.
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