&EPA
United States
Environmental Protection
Agency
Region I
Prepared by the
Operations^ Maintenance Section
Water Division
Boston, MA
June 1980
Energy Conservation
In Wastewater Treatment
Considerations For Design
Concepts and Operational
Parameters
HYDRONIC
SOLAR .
COLLECTORS
PROPANE
(STANDBY) 1
PLANT
EFFLUENT
f SOLAR
V. STORAGE
ELECTRIC
GENERATOR
HEAT
EXCHANGER
METHANE
BOILER
ELECTRIC
POWER
ELECTRIO—J
POWER
HEAT
I DISTRIBUTION
SYSTEM
ELECTRIC POWER
(SUPPLEMENTARY)
EXHAUST AIR
HEAT RECOVERY
PASSIVE
SOLA
DOMESTIC
HOT
WATER
WATER
HEATER
DIGESTER
HEATING
BUILDING
HEATING
BUILDING
VENTILATION
METHANE
STORAGE
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ENERGY CONSERVATION IN WASTEWATER TREATMENT
Considerations for
Design Concepts and Operational Parameters
Prepared by
Hibbard E. Armour, Chief
Operation & Maintenance Section
Water Division
United States Environmental Protection Agency
Region 1
William R. Adams, Jr.
Regional Administrator
June 1980
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Environmental Protection Agency
Region 1
TABLE OF CONTENTS
Purpose
Scope
Source of Information
Introduction
Designed-In Features
In-Plant Modifications
Process Modifications
Possible Future Design Concepts
Recommendations
Page
1
1
2
2
3
9
13
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COVER: The Wilton, ME Wastewater Treatment Plant - Photo and dLuLQHom
ojj the. de-6-t.gn e.ng-ine.&u> WtUgkt, P-teAce, BaAne-6, Wyman Emj-dteet^ o&
TopAhcun, ME. The design makes use of passive and hydronic solar
collectors, along with digester gas, to heat and otherwise fuel the
facility.
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Energy Conservation in Wastewater Treatment
Considerations for
Design Concepts and Operational Parameters
U.S. EPA Region 1
Purpose
This report was prepared in response to a National effort directing our
immediate attention to excessive use of energy in the treatment of the
Nation's wastewater streams. Subsequent chapters will be written to update
the information contained herein and to present identifiable case histories
of energy efficient plant designs and operations as we learn of their existence.
This report will serve to first identify energy conservation measures
being employed, and secondly to recommend new measures that should be
considered when planning for, and designing, future wastewater treatment
plants. This report, and its future chapters, will be distributed to
consulting engineers, State reviewing agencies, and to the operators of
existing plants.
Scope
The scope of this report includes the following energy related consider-
ations:
1. Those considerations that result in a direct savings on power
consumption.
2. Those considerations that would reduce fuel consumption.
3. Those considerations that could lead to the use of latent energy
sources which in turn would improve treatment efficiency and/or
operations.
The text includes measures that were designed into existing plants;
modifications that were instituted after the plants became operational; and
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those process control procedures that were developed by plant staffs in
attempts to reduce operating costs. Material pertaining to future design
concepts relates directly to innovative and alternative technology guidance
and to discussions on this subject with interested parties in the field.
Source of Information
The prime source of information for this report was the experience
gained through the close contact with operating wastewater treatment plants
that developed under the Regions' O&M program. Many of the details, and we
hope future case histories, were developed from the response to a questionnaire
completed by operators of existing plants. The coordination for this effort
to identify energy conservation measures was largely successful due to the
excellent support from Operators Associations and the State Operations
and Maintenance Offices.
Introduction
Experience shows that most of the existing wastewater treatment plants
located in New England were designed with little consideration given to
energy conservation either in power use or fuel consumption. At the time
that many of the plants were being constructed, or were in the planning
stage, the thought of an energy crisis was only a remote possibility. As the
National program to construct treatment plants built up steam, the demands
on the consulting engineers and the review agencies nearly overwhelmed all
concerned. One of the adverse affects of this situation was that too little
attention was given to inflationary trends that were developing in power
costs. Much of the action now being taken to counteract the high cost
of treating wastewater was developed through the diligent efforts
of the plant operators.
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The time is past due to recognize the energy problem and to start
designing facilities that are less expensive to operate. There is a
responsibility at both the Federal and State levels to produce guidance,
which if followed, will yield more economical treatment of wastewater.
The guidance is needed to educate the design and review engineers in
planning and design techniques that will insure proper energy considerations
in all future treatment works. The municipalities must in turn be
encouraged to undertake energy conservation practices, and/or plant
modifications, that can reasonably be accomplished using their local resources.
The following material is presented in four categories;
1,. Design-In Features
2. In-Plant Modifications
3. Process Control Modifications
4. Possible Future Design Concepts
The inplant modifications are offered basically to benefit the owners of
existing plants. However, this information is time-tested and as such
should be given consideration by the designers of new plants. The process
control modification information should be reflected in Operation and
and Maintenance Manuals being prepared for new and future plants.
Designed-In Features
The survey to identify existing energy conservation measures started
with an examination of the designs used to date, to determine which of
their features should be considered for the future. The following designed-
in features are offered for considerations:
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1. Anaerobic digesters have long been used to develop a stabilized sludge
and to produce a usable by-product - methane gas. Methane is
commonly used as fuel to heat the digesters and sometimes is used
to provide the necessary mixing in the primary digester. Plants
producing excess methane often have the capability to use the gas
in the plants' heating system or for heating plant water. Several
plants have the capability to use methane as the fuel to incinerate
grease and skimmings. A few attempts have been made to convert
combustion engines to digester gas. Generators and main pumps
serving the Boston MDC treatment plants are fueled by digester
gas. A narrow gage train, powered by digester gas, once hauled
incinerator ash from the Springfield plant to the landfill. The
designs of plants making use of methane all included the capabilities
to use fuel oil, natural gas, and methane. This foresight allows
the plant to use commercial fuels that offer the most competitive
price.
2. Many designs of anaerobic digesters incorporated features that
addressed energy conservation. Older designs provided digesters that
were below grade, and then later, provided earth embarkments around
the tanks to give insulation from the cold. The more modern
technique is to construct tanks with double walls insulated with
fiber-glass. Most digester designs, involving multiple tanks,
cluster the tanks in a manner that yields operational areas between
units. These areas are heated by the same equipment serving the
tanks and by heat that may radiate from the tank walls.
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3. The more sophisticated designs make use of multiple speed controls
on motors used to drive pumps and aeration equipment. The flexi-
bility provided by this element of control allows the operator to
properly pace his pumping rates and to supply only the amount of
DO needed to meet the demands of the bio-mass. Such optimization
yields the most economical use of electrical power. Instrumentation
and automatic controls are paramount in the efficient operation of
a sophisticated process train.
4. Some excellent plant designs provide a means to employ process units
that will match the volume of flow being received for treatment.
Such plants have compartmentalized aeration tanks, and/or multiple
units, to match flow demands. All too often a plant must be operated
as extended aeration, while it was designed for conventional operation
only because the tanks were too large to handle the flows generated
during the early life of the plant. This type of operation keeps
the waste under aeration for 24 hours while in truth it only
requires 6 hours. Very few existing plants are provided with flow
equalization tanks. Provision of this capability would greatly
reduce the power demands that result from hydraulic overloads.
5. The older treatment plants made maximum use of a hydraulic profile
to reduce power needs. Much can be learned from the classical
trickling filter design where full use was made of stand pipes and
automatic siphons. Even the distribution arms fully utilized
hydraulic principles to achieve rotation. All too often, today's
designs require one or two pumpings of the entire flow. Plants
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located in flood plains require effluent pumping over
flood walls, a condition that could be eliminated through better
siting. Everything possible must be done in the future to
increase gravity flow to the plant and through the process units.
6. Many of the new treatment plant designs are making use of principles
that have minimal demands on power consumption. The Oxidation Ditch
makes use of a brush aerator to provide mixing and oxygen transfer.
The mechanical equipment in this process has low horsepower
requirements. Some of the principles employed in the trickling
filter are currently being used in the Bio-Disc and the Bio-Tower.
The Bio-Disc requires very low horsepower to achieve rotation
while the Bio-Tower needs only pumping to provide treatment.
Ideally more use should be made of lagoons and stabilization ponds,
but due to space requirements such facilities are impractical in
much of New England.
7. Several of the larger new plants are making use of pumping devices
that are independent of power requirements or are designed to use
minimal power. A very efficient unit is the screw-pump which
provides completed variable flow control with only limited horse-
power input. Air-lift pumps require little power to function and,
with careful maintenance they perform quite well. Telescopic
valves have been in use for years and they operate only on a
differential hydraulic head which needs no power input.
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8. More of the major plant designs are giving consideration to weather
protection. It is becoming common to find enclosed headworks
where the enclosure is accomplished by using fiber-glass. This
material is attractive and allows the passage of light to the
interior. The sun's rays provide sufficient heat to eliminate
freezing of the automatic sampling equipment. A few of the new
designs are providing covers for tanks such as the final clarifiers,
aerobic digesters, and the chlorine contact chambers. This form
of protection traps any latent heat associated with the incoming
flow and reduces the risk of freezing. Plants designed in parallel
often locate units in a manner that provides underground work
areas, sampling stations, and pipe galleries throughout the system.
Minimal heat is needed to keep such space heated and the problem
of freezing is eliminated. There have been some attempts made to
cover sludge drying beds. However, most of the past efforts have
had only limited success due to the use of vandal- prone materials.
9. The feature of the wastewater treatment that most impacts on fuel
consumption is the incineration of sludge. Much of the problem is
associated with the lack of efficiency in sludge drying equipment.
Equipment suppliers' claims often fall short of their mark, and in
most cases, the expertise needed to run the equipment is beyond
that which exists in the plant. The most promising hope we foresee
in the future lies with the various presses that are appearing on
the market today. When the sludge dewatering equipment fails to
achieve the dryness to support burning, very expensive fuel must be
added to support the incineration process. There are at least two
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heat treatment units designed to improve the dewatering and burning
characteristics of the sludge. The heat source available to support
these units is the major factor that determines whether or not
they will be used after installation. The efficiency of the more
classic sludge drying systems is usually chemical dependent. The
better designs provide means to use both polymers and metal salts
for conditioning. In this manner the operator can optimize the drying
process and improve incineration thus reducing the use of fuel.
10. Designers of small treatment facilities have provided several plants
with wedge-wire units to dewater sludge. These units are energy
free and are capable of matching many of the mechanical units that
are in use today.
11. Existing designs frequently fail to consider haul distance to
sludge disposal sites. The increase in fuel costs is having a
serious impact on this non-process related activity. Similarly, many
plants are burdened with sprawling layouts and extensive lawns.
With the increased cost of fuel and labor the municipalities can
little afford such luxuries.
12. Good plant designs provide adequate removals of gross solids,
grease, and grit, prior to the process tanks. Escaping solids will
result in overloading of any mechanical equipment that they come
in contact with. Grit can, and often does, produce undue drag on
scraper mechanisms. Excess grease results in increased demands on
the aeration equipment and usually involves a complicated sub-
system that is energy wasteful.
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13. Older plant designs provided a pre-aeration capability which
freshened raw waste and improved grease removal. This feature
tended to reduce the aeration demand in the process tanks.
In-Plant Modifications
In-Plant modifications are those energy related changes that were
implemented after the treatment plant was considered as operational.
Some of these changes were accomplished by the consultant after the fact,
but most of them resulted from the efforts of conscientious operators.
These modifications are presented for consideration by owners of existing
plants and by the designers of new plants.
1. Many of the plant operators have found it necessary to provide
weather protection for exposed process units and equipment.
Equipment containing conveyor mechanisms/ such as grit systems, have
been protected by wrapping with insulating material. Automatic
samplers and exposed meter housings have been protected by insulating
and installing incandescent lamps to provide heat. Many attempts
have been made to cover process tanks and sludge drying beds.
Proper support for cover material has been a problem in areas with
heavy snow loads.
2. Operators have found it necessary to provide weather stripping and
other insulation in their buildings to conserve heat. This has
allowed them to lower heating temperatures and save fuel.
3. Lighting systems installed in treatment plants often light entire
interiors. Operators have modified these systems to supply light
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in work zones thus reducing the use of electricity. A few have
installed automatic switches to turn exterior lights on and off
with changes from daylight to darkness.
4. Operators have installed capacitor starters on major electric motors
to reduce start-up surges. Most electric rates are based on peak
demand loads. While the starters do not reduce power use, they do
reduce the peak demand load and therefore reduce power cost.
Capacitors are installed on line to tailor lagging power factors
associated with alternating current. Lagging power factors impact
adversely on power costs.
5. Plants that were not equipped with variable speed controls attempt
to achieve desired control by installing timers on pump and
blower circuits. The success of such modification often depends on
the reliability of the designed-in metering system.
6. More precise control of pumping rates sometimes requires modification
of the drive mechanisms themselves. This can be accomplished by
varying the distance from the drive elements to the motors or by
changing the sheaves or pulleys.
NOTE: Items 5 and 6 are energy related in that they serve to optimize plant
operations. Optimization yields highest efficiency in both process
control and power use.
7. The more progressive operators are experimenting with chemical
additives to improve process efficiency. As such they are finding
it necessary to improvise chemical feed systems.
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The feed systems require metering control which may only entail timed
discharge. Chemical feed may be by gravity, siphon, or if available,
by metering pumps. Application is sometimes provided in-line on
the discharge side of a pump, or may be in the form of batch dosage
to a holding tank. Sludge conditioning prior to discharge to a
drying bed may be accomplished directly at the splash pad or into a
trough used for sludge distribution. Proper use of chemical additives
and conditioners increase operational efficiency and in the case
of sludge, increase solids concentration. Conditioning reduces
drying times with corresponding savings in energy.
8. Many operators have installed in-line sampling points to provide
better control over pumping operations. Periodic sampling during
cycles of sludge pumping allows the operator to evaluate concentration
of solids. Operators, who only have timed cycles to depend upon
for control, may be wasting energy by pumping dilute solids or just
plain water. The pumping of dilute solids will have an adverse
effect on most process units receiving the flow. The pumping of
excess water can result in excessive supernatant washouts that
will produce serious sidestream overloads. These in turn can
raise oxygen demands and otherwise cause process imbalances that
can take days or weeks to correct.
9. Many operating facilites have found it necessary to install finer
screens or bar racks to limit the amounts of gross solids entering
the plant. This action protects downstream equipment and reduces
the chances for overloads caused by foreign materials hanging up on
pump impellers or aerator blades.
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10. The hauling of sludge during cold weather is often complicated by
the load freezing to the truck bed. At least one operator changed
the truck bed and replaced it with an aluminum unit constructed
with hollow sidewalls. The truck exhaust system was modified to
discharge its hot gases into the sidewall cavity thus heating the
unit and preventing freezing.
11. Many operators have painted dark work areas with light colors. This
results in less power demand to illuminate the area and also
improves its appearance.
12. Large plants equipped with incinerators are beginning to take
advantage of new sludge drying technology. Where working budgets
allow, conventional drying equipment is being replaced by presses.
Some of the more innovative plants have received R&D funding to
experiment with untried sludge drying concepts. The results of
these endeavors are being closely evaluated to insure that successes
are documented and made available to designers of new facilities.
13. Quite often operators of new plants find that little thought was
given to ease of handling equipment or supplies being received.
In at least one case, all loads had to be removed from the shippers
truck and placed on a smaller vehicle so that they could be
unloaded at a desired location. This procedure was not only a
nuisance but it was energy expensive in both manpower and fuel
consumption. Modifications of door clearance and installation of
loading docks were necessary to correct the situation.
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Process Modifications
Process modifications are presented to assist the existing plant
staff in reducing energy usage and to provide energy related guidance for
the writers of O&M manuals.
1. The most dramatic savings in fuel consumption is being achieved by
plants equipped with incinerators but who are permitted to dispose
of sludge after lime stabilization rather than by burning. Unfort-
unately this practice is not making use of expensive equipment funded
largely through Federal grants. A more acceptable solution to the
problem of high incinerator operating costs would result from the
production of dryer sludge that would burn with little or no added
fuel. Municipalities utilizing lime stabilization are exploiting
landfill areas that will at best have only limited life. Their
early consideration should be given to measures that will improve
their sludge burning efficiency.
Small plants in rural areas are frequently permitted to by-pass
sludge drying equipment for land disposal of wet, aerobically
digested, sludge. This operation has little if any energy related
benefits other than the savings in manpower expended. Any savings
in power costs related to non-use of mechanical dewatering equipment
is offset by the gasoline used for transport.
2. Operators concerned with the conservation of energy are constantly
trying to peak the efficiency of their process units. More attention
is being directed to the optimization of powered equipment. Plants
in Vermont are encouraged to borrow and use State owned recording
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ammeters to identify surges and other phenomena that adversely affect
power consumption. These plants are also required to equate power
used to BOD removal in a State sponsored program to determine which
modes of operation produce the highest efficiency with the least
expenditure of energy. In addition to trying for peak operation of
equipment, the good operator watches sludge blanket depths, measures
solids concentrations, and watches DO parameters in all process
stages. Sludge blankets have a direct effect on concentrations and
in turn impact on pumping efficiency. High DO may indicate
excessive aeration. Either of these factors will translate to
higher power costs.
3. Proper maintenance of plant equipment is necessary to achieve a
high degree of energy conservation. Poor maintenance results in
wear and loss of efficiency. Improperly installed bearings will
increase friction and cause the burn-out of equipment. Trash
collecting on impellers causes an imbalance which produces vibrations,
wear, and possible overload of motors. Clogged chemical feed
lines reduce pump efficiency. Misaligned chains and drives produce
unnecessary loads on motors. Accumulations of grit and solids
can overload scrapers and collectors. Freezing conditions can and
will overload any exposed mechanical equipment.
The above listing is far from complete with respect to maintenance
factors that impact on energy use. However, the point is hopefully
made that operators and maintenance personnel can play a major role
in answering the energy crunch by performing their routine duties.
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4. One of the most universal problems facing treatment plant operators
is the processing of waste sludge. Gravity thickeners provide sufficient
concentrations for primary sludge but are inefficient for
concentrating waste activated sludge• Designs sometimes provide
gravity thickeners to concentrate mixed primary and waste activated
sludges. Little efficiency is achieved in combining the sludges.
The solids concentration is too low for efficient dewatering and
the supernatant from the thickener produces a strong sidestream.
Both conditions result in loss of unit efficiency and higher power
costs.
- Flotation thickeners are quite efficient in concentration waste
activated sludge. Chemical additives enhance thickener operation
and may well also improve the sludge dewatering. Efficient operation
of flotation units will save energy throughout the entire sludge
process chain.
- Thickening of sludge frequently must be accomplished in aerobic
digesters prior to their dewatering. The most common practice
used by operators to thicken this sludge is simply shutting off
the air supply and allowing the solids to settle. The free stratum
of water at the liquid surface is then pumped, siphoned, or drained
off leaving the solids in a thickened state. Decanting becomes a
problem in digesters equipped with fixed mechanical aerators. As
soon as free liquid is removed from the tank, the surface falls
below the aerator blade and mixing and aeration is lost unil more
liquid is added. Diffused air on the other hand provides mixing
and aeration no matter how much liquid is removed.
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The efficiency of concentrating solids in digester tanks is the
subject of several plants experimentation. Lab tests show that
high cationic polymers will induce coagulation and will in turn
produce rapid settling. Batch applications of chemicals in digester
tanks may well solve the problem of concentrating sludge before it
reaches the downstream process provided to accomplish dewatering.
The more concentrated the sludge is, the less energy is required
for the drying operation.
5. Several communities in New England are under Enforcement Orders to
haul sludge from their plant for proper disposal elsewhere. This
is being accomplished by using tank trucks for transport at a high
cost per load. Operators faced with this problem are exploring the
possibility of concentrating waste sludge through the use of chemical
additives. Reductions of sludge volumes ranging up to 75% have
been achieved in less than one hour in bench scale tests. Such
a reduction in real operation would greatly reduce the burden of
hauling sludge.
6. Activated sludge plants having empty aeration tanks often convert
the inactive units into aerobic digesters. This conversion provides
a capability to supplement existing digesters and to achieve volatile
solids removal that could not be otherwise accomplished. This
operation in itself is energy intensive. However, the net improvement
to overall plant efficiency may yield positive returns.
7. Operators oust exercise emergency generators on a fixed schedule.
This may be accomplished either under loaded conditions or with no
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equipment on line. The more prudent operators choose to run under
the loaded condition and in turn receive the benefit of saving
commercial power during the test periods.
3. Many operators install curtains or other splash protection devices
around process units to reduce the amount of cleaning necessary
after unit operations. This action saves manpower and reduces the
amount of plant water that would have to be pumped for clean-up.
9. Plants using lime for pH control or sludge conditioning sometimes
find that slurry can be purchased at about the same price as powdered
lime. The use of slurry saves power otherwise used to mix the dry lime.
Possible Future Design Concepts
The future of wastewater treatment plant design holds a universe
of yet to be discovered technology that will most effectively be tapped
by the need to conserve energy. In the past we saw the evolution of
facilities designed to remove settleable solids using principles requiring
minimal expenditures of energy. The present brought the demand for a
degree of sophistication that would yield secondary or tertiary removals,
and with this demand, the construction of the energy gluttons that now
treat our wastewaters.
Future design concepts must not only preserve the best that the past
and present has to offer, but they must freely incorporate new principles
as they evolve. These new principles often are proven through funding
available from the EPA Research and Development Program. Once proven, they
may well be considered for innovative or alternative incentives offered
under the Federal grants program.
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The Clean Water Act of 1977 clearly established the intent of Congress
to encourage the use of innovative and alternative technology with emphasis
on increased energy recovery and conservation, reuse, and recycling. The
monetary incentive provides a grant increase of from 75% to 80% for those
projects with designed-in features qualifying as examples of innovative
or alternative technology.
The following list contains a few possible design concepts that may
warrant consideration in future treatment plant designs. The concepts
draw from past and present technology, and reflect some possible ideas
from the future.
1. New designs of biological treatment systems should contain provisions
to minimize demand for mechanically supplied oxygen. Plants treating
strong wastes might well employ roughing units, such as bio-discs or
towers, upstream of aeration tanks to reduce the oxygen demand of the
raw waste. More consideration should be given to employing equalization
tanks since these units would reduce the chance of solids washout.
Loss of solids reduce process efficiency and therefore result in aeration
without achieving effluent quality. Perhaps the most effective way
to reduce aeration demands is by provision of flexibility in tank
configuration. Design the tanks so that the plant can operate in
their design mode with all foreseeable flows. A majority of new
facilities are forced to operate in the extended aeration mode
until they receive sufficient flow to be operated as designed.
2. The amount of pumping in a new plant may be reduced by providing
better hydraulic profiles and thus allowing more use of gravity
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ERRATA SHEET
ENERGY CONSERVATION IN WASTEWATER TREATMENT
Consideration for Design Concepts and Operational Parameters
(June 1980)
Page 18 - first paragraph - second sentence; should read:
The monetary incentive provides a grant increase of from 75% to 85% for
those projects with designed-in features qualifying as examples of innovative
or alternative technology.
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flow between units. Use less energy dependent pumping units such
as the screw pumps, air-lift pumps and telescopic valves. Provide
pump flexibility that will match the demands of the flow being
treated as well as that flow the plant was designed to treat.
Many new plants are forced to return sludge at rates far in excess of
demands simply because there is no way to further reduce the pumping
rate.
3. New designs for activated sludge plants should give consideration
to improving the biological activity. Thought might be given to
wasting excess heat from incinerator stacks through aeration tanks
so that more constant temperature can be maintained in the mixed
liquor. Similarly, waste heat could be blown through hybrid
trickling filters to improve winter activity.
4. A patent has recently been issued to protect a "man-made"
micro-organism that will assimilate oil waste. Advances in this
field may well produce the bio-mass of the future that will be used
to clean our wastewaters.
!5. More consideration should be given to renewing the use of anaerobic
digesters. These units are still one of the most efficient means
of solids reduction we have. The production of gas has the potential
to provide usable heat, generate electricity, and to power vehicles.
The introduction of garbage and other high organic waste into the
system has some potential to increase gas production.
6. Improved weather protection is needed in most plants located in New
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England. Plastics that will transmit light and solar heat should
be used where possible.
7. More heat must be obtained from sources other than our fossil fuels.
Solar panels and heat pumps are becoming more popular in the newer
treatment plants.
8. New technology is being developed in the field of sludge reuse.
One of the most reusable products today is developed through
composting. The residue is used as a soil conditioner. Recently, a
salvage company contracted to purchase a town's sludge so that it
could reclaim precious metals that escaped from industry. More
consideration should be given to this potential for reclaiming
chemicals and minerals.
9. Consideration should be given to the possibility of generating hydro-
electric power at the discharge end of the treatment plants.
Recommendations
The following recommendations are offered to encourage better
utilization of energy saving measures in the design, modification, and
operation of wastewater treatment plants.
1. The planners and designers should seek ideas and guidance from
operating facilities where efforts have been made to reduce energy
usage. Research of existing design concepts should be conducted
to identify energy saving principles that might be modernized for
future use. Application should be made for R&D grants to prove
out untried design and operations concepts. Full use should be
made of the incentive program associated with I/A technology.
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2. The owners of operating facilites should initiate energy surveys of
their facilities to learn where saving might be realized. They
should strive to optimize the efficiency of each process unit in
their system. The owners must encourage their operators to save
energy and in turn/ the operators recommendations must be supported.
3. The operator and maintenance personnel are the key to energy
conservation in wastewater treatment. They must achieve the optimization
that is necessary to provide the highest removal rates with minimum
pDwer or fuel expenditure. They must provide the maintenance to
insure that all equipment and process units are working at peak
efficiency. The plant personnel must seek ways to improve
operations, or to modify equipment, so that efficiency is improved
and energy demands are lessened.
It is requested that the consulting engineers, the State and Federal
reviewers, and the operators of facilities, all make an effort to provide
us with suggestions, case histories, or other data that can be used to
promote the energy conservation cause in the treatment of wastewater.
Your contribution should be sent to:
Hibbard E. Armour, Chief
Operations & Maintenance Section
Water Division
JFK Federal Building
Boston, MA 02203
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