United States
Environmental Protection
Agency
Office of Water
Programs Operations (WH-547)
Washington, DC 20460
February 1982
EPA 430/9-82-002
C. 5-
c/EPA
Water and Waste Management
Energy Management
Diagnostics
-------
This publication was prepared with the support of a
grant from the U.S. Environmental Protection Agency's
Municipal Operations Branch. The statements, conclusions
and/or recommendations contained herein are those of the
authors and do not necessarily reflect the views of the
U.S. Government, the U.S. Environmental Protection Agency,
or the Municipal Finance Officers Association.
-------
ENERGY MANAGEMENT DIAGNOSTIC
C; i " " - ,. : . - '> ^'uOU-'r
-------
c-
"
c
o
S-
CD
v~-
r.
UJ
GO
-------
TABLE OF CONTENTS
INTRODUCTION !
ENERGY USAGE IN WASTEWATER TREATMENT 2
WHAT TYPES OF ENERGY ARE USED 2
WHERE ENERGY IS USED 2
HOW ENERGY IS USED 5
APPROACH TO PERFORMING AN ENERGY AUDIT 5
DEVELOP AN ENERGY USE BASELINE 6
CONDUCT ON-SITE FACILITY SURVEY 9
IDENTIFY ALTERNATIVE ENERGY CONSERVATION MEASURES ... 9
PERFORM AN ECONOMIC ANALYSIS OF ALTERNATIVES 11
DEVELOP AN ENERGY MANAGEMENT PLAN 12
DIAGNOSTIC CHECKLIST FOR ENERGY MANAGEMENT
OF WASTEWATER FACILITIES 14
REFERENCES 35
-------
ENERGY MANAGEMENT DIAGNOSTIC
INTRODUCTION
Most of the wastewater treatment facilities constructed in the United
States were either designed or under construction by the early 1970's, at a
time when energy was considered to be relatively inexhaustible, dependable
and inexpensive. Because of this, these facilities were designed with an
emphasis on performance, not energy efficency. Since the 1973-1976 OPEC oil
embargo, energy availability and costs have become major concerns to waste-
water treatment managers. Energy costs (both fuel and electricity) represent
a significant portion of the total costs of operating today's wastewater
utilities, in many instances accounting for 20-25% of the total operating
cost. It is critical for utility managers to identify energy management
techniques to control energy usage and costs without sacrificing utility
operations.
This manual will familiarize local officials and utility managers with
the principles and practices of sound energy management, specifically applied
to wastewater utility operations. To accomplish this, the manual presents
the following:
a review of energy usage in wastewater treatment;
a method for performing an energy management audit; and
a series of checklists for energy management in a wastewater facility.
From this, managers will become familiar with: the types of energy usage in
their facility, the energy conservation and management techniques available
to control energy consumption and costs, and the approach to evaluate and
implement energy management practices within their facilities.
-------
ENERGY USAGE IN WASTEWATER TREATMENT
An understanding of energy usage and its cost implications is important
to an understanding of energy management alternatives. A review of energy
usage in wastewater treatment must consider:
what sources of energy are used;
where energy is used in the facility; and
how energy is used.
What Sources of Energy Are Used
Several sources of energy are used in wastewater treatment including
electricity, fuel oil, natural gas, methane and gasoline. In addition both
wood and solar energy are beginning to be used in certain instances for heat-
ing. Of the types of energy used, electricity accounts for about 75% of the
consumption, primarily to operate electric motors throughout the facility.
Fuel oil, natural gas and methane gas are used for building heating, sludge
treatment and sludge disposal. Gasoline is used for vehicles involved in
operations, maintenance and sludge disposal. The selection of a particular
fuel depends on its availability and costs and the type of treatment process
being used.
In addition to energy used directly at the treatment facility, secondary
energy is required to manufacture materials used in the treatment process.
This includes both the materials used in constructing the facility, such as
cement and steel, and the materials consumed in the treatment process, such
as chemicals. Secondary energy requirements for construction materials is
generally not a concern of utility managers, however, the secondary energy
requirements for consumables should be considered. As energy costs increase,
those chemicals that have large energy requirements to manufacture are likely
to increase in cost faster than other chemicals. This may affect the selec-
tion of energy conservation options. Exhibit 1 lists the chemicals
commonly used in wastewater treatment and the estimated energy requirements
for production. Additional information can be found in EPA publication
MCD-32, "Energy Conservation in Municipal Wastewater Treatment."
Where Energy Is Used
The major areas of energy consumption within wastewater facilities are
in the treatment processes themselves. For a typical wastewater facility,
major energy consumption is required for pumping, secondary treatment, sludge
dewatering and sludge disposal. Less significant amounts of energy are
required for buildings and structures which require energy for heating, ven-
tilating, air conditioning and electrical lighting. Exhibit III-2 illustrates
the relative energy usage for various treatment processes for a wastewater
facility.
-------
EXHIBIT
1
ESTIMATED ENERGY REQUIREMENTS FOR THE PRODUCTION
OF CONSUMABLE MATERIALS
Material
Activated Carbon
Alum
Ammonium Hydroxide
Carbon Dioxide
Chlorine
Ferric Chloride
Lime (Calcium Oxide)
Methanol
Oxygen
Polymer
Salt (Sodium Chloride)
Evaporated
Rock & Solar
Sodium Hydroxide
Sulfur Dioxide
Sulfuric Acid
Fuel
Million Btu/ton
102*
2*
41*
2
42
10
5.5*
36*
5.3
3*
4*
0.5
37
'0.5
1.5*
Electricity
kwh/lb
4.9
0.1
2.0
0.1*
2.0*
0.5*
0.3
1.7
0.25*
0.1
0.2
0.024*
1.8*
0.024*
0.1
*Indicates principal type of energy used in production.
Energy Conservation in Municipal Wastewater Treatment, MCD-32.
-------
EXHIBIT 2
TYPICAL ENERGY USE PROFILE
FOR
WASTEWATER TREATMENT PROCESSES
7
6
Z
0
H 5
a. °
2
(O
O
o
>
o
£E
UJ
z
UJ
UJ -
> 3
pi
<
UJ
(C
2
1
0
o
«
J
.
o
*"
»
PRIMARY ENERGY T5
1 1-
0)
IH SECONDARY ENERGY 1
1<
UJ
18 S,
ffi -0
I 2.
- W
S -o
o o
7 g
o 5
o <
^
o
a
o
Z
1
o
o
W
c
2-
a
^J
ig
c
(0
0
"5
(0
(0
o
o
a.
?
Z
o
^
,0
CB
|
o
~
:::::;
^
:%%
INFLUENT AND SECONDARY SLUDGE
INTERMEDIATE TREATMENT TREATMENT
PUMPING
">
i
o
^v
=)
£
a>
o
(O
BUILDING
HEATING AND
COOLING
Source: Processes-Not Products-Biggest Energy-Saving Factors Water & Sewage Works,
November 1980
-------
It is important to understand where energy is consumed in the utility so
that the analysis of alternatives is properly directed. For example, as
indicated in Exhibit 2, "building energy," for lighting, heating and
cooling, represents only 10% of the total energy requirements of the facility.
If this energy consumption can be reduced, say 20%, through alternative energy
conservation options, it only reduces total energy usage by 2%. However,
even a modest reduction in the percentage of energy consumption in secondary
treatment or sludge treatment can have a significant impact.
Energy usage, by wastewater treatment process, is identified in detail
in the EPA publication "Energy Conservation in Municipal Wastewater Treat-
ment," previously cited. This publication can be used by utility managers to
better understand the energy requirements of their specific facility
operation.
How Energy Is Used
How energy is used and at what rate, particularly electricity, has a
significant affect on costs. For example, electrical energy is measured and
charged based on both quantity and demand. The quantity of power used is
measured in kilowatt-hours (Kwh) and electric utilites typically charge for
this consumption on a unit basis. Electric utilities also charge for the
peak power or demand, measured as kilowatts (KW), used by a consumer. Peak
demand may only occur for 10-30 minutes a month. But the charge is assessed
because sufficient generating capacity must be provided to meet these short-
term peaks. Electric utilities use time-of-day rates for both quantity and
demand to help distribute energy usage more evenly and reduce the need for
excess capacity. Electric utilities also charge based on efficiency of the
treatment equipment consuming the power. Efficiency is based on a power fac-
tor which measures the difference between actual demand and apparent demand.
All three charges; quantity, peak demand and power factors can be controlled
by energy conservation options.
APPROACH TO PERFORMING AN ENERGY AUDIT
A systematic approach should be followed to assess energy usage, identify
and evaluate energy conservation options and implement an energy management
plan.
An energy audit is carried out in the following five steps:
develop baseline information on energy consumption and costs;
conduct an on-site facility survey;
identify alternative energy conservation measures;
perform an economic analysis of each alternative; and
develop an energy management plan.
-------
These five steps are depicted graphically in Exhibit 3 and described in
greater detail in the following sections.
Develop An Energy Use Baseline
The initial step in conducting an energy audit is to develop sufficient
baseline information to evaluate possible conservation alternatives. This
includes data about the type of energy used, costs, design conditions and
operating procedures.
To develop the baseline, the following basic data should be gathered in
preparation for the on-site review:
energy consumption and its cost for one or more previous years,
including electric utility billing records, internal electric meter-
ing records available, and records of purchased fuels. To the extent
possible, energy consumption should be determined by unit process.
Exhibit A is a form that can be used for collecting and summariz-
ing consumption and cost data.
utility rate schedules to determine if the utility is obtaining the
best rates available or if modifications could be made to obtain a
better rate. Utility representatives should be contacted for infor-
mation about future rate changes that will offer energy management
alternatives. These changes might include changes in demand metering
equipment policies or changes in time-of-day rate schedules.
design data, including original plans and specifications, equipment
manuals, and as-built drawings, to determine the accuracy of equip-
ment specifications and electrical ratings.
operating and maintenance logs, to evaluate how equipment is being
operated and maintained and how its performance might be improved.
water and sewer billing records, to determine the amount of extraneous
flow that is reaching the treatment facility. This can significantly
increase energy consumption.
From the available data, energy consumption profiles should be deter-
mined. They can be developed directly from metering records or estimated
using equipment ratings multiplied by overall average running times and load
factors. Profiles should be developed:
by fuel type (electricity, gas, fuel oil, wood);
by unit process (pumping, primary treatment, secondary treatment,
sludge treatment, sludge disposal, building energy); and
by performance indicators (flow, pounds of BOD removed, pounds of dry
solid removed).
-------
ENERGY AUDIT METHODOLOGY
ENERGY BASELINE
Base your
Utility and
Fuel Bills
I
U
F
^
Equipment
Specifications
Internal
Utility and
Fuel Accounts
Base Year Energy Use
Profile
FUEL TYPE
PROCESS
PERFORMANCE INDICATORS
ON-SITE SURVEY
IDENTIFY ENERGY
CONSERVATION OPTIONS
EVALUATION
OF OPTIONS
DEVELOPMENT OF
ENERGY MANAGEMENT PLAN
Physical
Inspection
Operating
Records
Maintenance
Records
1 Operating
9
»
> . »
Housekeeping
Minor Process
Improvements
Major Capital
Retrofit
i
Simple
Payback
Life Cycle
Costing
**
I
Procedu
Develop
Bu
I
Schedul
^
Perforn
Budgets
M
bd
-------
5
EXHIBIT
o
0
>
o
5
f
c
<
o
1
I. I
o !
-------
A typical energy profile is shown in Exhibit 5. Daily operating records
should be compared to utility bills to determine the relationship between the
treatment facility's energy usage and the electric utility's peak demand in
the operation of various unit processes.
Conduct On-Site Facility Survey
The next step in evaluating energy conservation options is to conduct a
physical survey of the facility. During this survey, the following activities
should be performed:
review operating procedures for each unit process including startup
procedures, equipment cycling, operations sequencing, energy recovery
capabilities, and process operations efficiency.
inspect equipment and review maintenance records to determine current
state of repair including lubrication, alignment, replacement of worn
parts, flow impairment, proper instrument calibration, and leaks;
observe building energy systems and their use including lighting,
heating, and cooling; and
review process flexibility with chief operators to identify opportu-
nities to shift process operations without impairing treatment
efficiency.
Identify Alternative Energy Conservation Measures
Based on the profiles of energy use and costs and the physical survey,
energy conservation measures should be developed. Generally, conservation
measures are grouped into three categories:
Housekeeping - These measures can be implemented immediately by modi-
fying operations or operating procedures with no special outlay.
This could include such techniques as shutting off equipment when not
needed for operations, reducing equipment cycling to improve its
operating efficiencies, changing operation sequences to reduce elec-
tricity demand, adjusting equipment to improve its efficiency, fine-
tuning process controls, reducing unnecessary lighting, reducing
thermostat settings, and improving maintenance.
Minor Process Improvements - These require minor capital investment
with a short payback period generally financed from current mainte-
nance budgets. They usually have little impact on process operations.
This would include such techniques as installing smaller pump
impellers, installing timers to cycle operations automatically,
installing capacitors to improve the power factor, and using digester
gas for heat treatment.
-------
EXHIBIT a
TYPICAL ENERGY USE PROFILE1
I I I I I » I
I I I ' ' I
DAYS OF MONTH
1 Variations may be caused by increased flows, due to infiltration/in flow, or cycling of equipment for
various process operations.
-------
Major Capital Retrofit - These require major capital investment and
may affect process operations. These include converting to filter
press dewatering to increase solids content and reduce energy
requirements, providing solar heating equipment, converting to
anaerobic digestion, or installing variable speed controls.
To help identify alternative energy conservation techniques, a series of
energy diagnostic checklists is provided at the end of this chapter. The
checklists also identify available reference material for more detailed
information on wastewater utility energy conservation.
Perform An Economic Analysis Of Alternatives
For each energy conservation alternative, an economic analysis should be
performed to justify the cost of its implementation. The detail required
depends on the type of alternative. For example, housekeeping alternatives
are almost always economically justified even though the energy savings may
be difficult to quantify. For minor process improvements, a simple payback
period analysis which identifies the number of years required to recover
initial costs is normally sufficient. Simple payback period is expressed as:
Payback period (years) = Initial investment ($)
Annual savings ($/yr)
This analysis is performed in the following steps:
estimate the alternative's reduction in energy consumption;
estimate the alternative's cost impact by reducing demand surges or
peaks;
estimate total impact, if any, of power factor penalties;
estimate any resulting increase or decrease in operation and mainte-
nance cost;
estimate total annual cost savings;
estimate initial capital investment, including equipment and instal-
lation; and
compute the simple payback period.
Simple payback is a quick and easy comparison technique but its limita-
tions should be kept in mind. It does not distinguish between alternatives
with different useful lives. Nor does it consider the value of money over
time, the impact of inflation, or the fact that annual energy costs are
increasing at a rate faster than capital costs.
11
-------
For major capital alternatives, a more detailed, life-cycle cost analysis
should be performed. This analysis considers the initial capital investment
of the alternative, the useful life of the equipment involved, the cost to
maintain the equipment, and the annual energy savings over the useful life.
Life-cycle costing is similar to the cost-effectiveness analysis required for
comparison of alternatives in 201 facilities planning. Essentially, if the
present value of the annual savings is greater than the present value of the
alternative's cost, it is economically justified.
Additional information on conducting detailed economic analysis of energy
conservation options is contained in "Life Cycle Costing Emphasizing Energy
Conservation," by the Energy Research and Development Administration, (Depart-
ment of Energy), May 1977.
Based on the economic analysis, energy conservation options should be
ranked according to cost-effectiveness and implementability.
Develop An Energy Management Plan
An energy management plan should be developed to ensure proper implemen-
tation of the energy conservation options chosen as a result of the evalua-
tion. The plan includes the following activities:
planning;
implementing; and
monitoring.
Planning includes revising operations and maintenance procedures where
necessary to implement housekeeping alternatives, developing purchase/instal-
lation specifications or work orders for minor process improvements, and
developing capital budget documentation to support major capital improvements.
Implementing involves assigning of responsibility to individuals who
have sufficient authority to allocate resources, resolve conflicts, and
establish schedules. Overall implementation schedules should consider the
budget approval process, design or procurement requirements, and installation
requirements. Improvements should be scheduled to minimize their impact on
facility operations.
Monitoring requires the establishment of performance targets by energy
type, by process, and for the facility as a whole to track the program. These
should be based on the baseline energy profiles. Performance targets should
be evaluated on a periodic basis (e.g., monthly based on utility billing) to
assess whether energy consumption is consistent with the energy management
plan. The targets should be revised as the energy conservation options are
brought on line. Exhibit 6 illustrates the type of management reporting
form that can be used.
12
-------
EXHIBIT
MONTHLY ENEBGY REPORT
FORM'
FAC1UTY OR OPERATING UNIT.
MONTH.
u
A
^
0
s
T
P
R
1
C
P
E
R
F.
T
N
D
I
C
A
T.
USAGE (YTD)*
BASE YEAR TO DATE
PERCENT ABOVE (BELOW) BASE YEAR
COST (YTD) - DOLLARS
BASE YEAR COST (YTD)
PERCENT ABOVE (BELOW) BASE YEAR
COST PER MMBTU** (CUP.RENT MONTH)
BASE YEAR COST
PERCENT ABOVE (BELOW) BASE YEAR
USAGE PER 1000 GALLONS
BASE YEAR USAGE PER 1000 GALLONS
PERCENT ABOVE (BELOW) BASE YEAR
COST PER 1000 GALLONS
3ASE YEAR COST PS? 1000 GALLONS
PERCENT ABOVE (BELOW) BASE YEAR
£l£CTRIC
GAS
OIL
OTHER
Y5AR-~0-CATE
"MIUJCN STU
13
-------
DIAGNOSTIC CHECKLIST FOR ENERGY MANAGEMENT OF WASTEWATER FACILITIES
The following energy management diagnostic checklists are provided to
assist utility personnel in performing an in-house review of energy consump-
tion around the utility and evaluate energy conservation options. The check-
list is designed for use after the utility has developed its baseline
profiles, or has set targets for energy use.
The checklist is organized as follows:
Column 1 - identifies process phase;
Column 2 - identifies typical energy uses for each process phase;
Column 3 - provides methods to identify energy inefficiencies;
Column 4 - identifies potential conservation measures;
Column 5 - identifies cost and benefit considerations;
Column 6 - identifies potential adverse impacts on utility operations;
and
Column 7 - identifies selected references for more detailed informa-
tion. The list of references is attached at the end of the
checklist.
14
-------
PROCESS/ STEP
I. PUMPING:
CONVEYANCE AND
PRIMARY SYSTEMS
I1
Ui
ENERGY USES
Fuel for engine-
driven pumps.
INDICATIONS OF
ENERGY
INEFFICIENCIES
1. Poor performance (e.g.
hard-starting, back-
firing, etc.) or ex-
cessive fuel consump-
tion.
2. Not using digester
gas, If available.
3. Operating at less
than 50% of design
load (low flow, ex-
cessive discharge
throtting, etc.).
4. Large reactive load
(power factor 0.8
or less) .
5. Excessive electrical
demand.
POTENTIAL
CONSERVATION
MEASURES
1 . Tuneup .
2. Substitute digester
gas for purchased
fuel.
3A. Shut down unnecessary
pumps .
B. Install variable
speed controller.
C. Replace with smaller
high efficiency pump.
4. Install capacitors to
increase power factor,
or variable speed
driver or synchronous
motors.
5. Install demand limiter
COSTS &
SAVINGS
1 . Costs :malnte-
nance. Savings;
reduced fuel
consumption.
2 .Cost: equipment
reconfigura-
tion. Savings :
purchased fuel.
3A. Costs:none.
Savings :
energy.
B. _Costs_: equip-
ment. Savings:
energy.
C. Costs:equip-
ment . Savings :
energy.
4. Cost : capa-
citor as a
function of
electrical
size versus
reactive load
savings.
,5. Gost : in-
stallation and
operation.
Savings : demand
charges .
I'OTKNTIAL
IMI'ACT ON
OPERATIONS
1 . None
2. May need standby
operations .
3A. Inadequate pump
ing if pumps
remain off dur-
ing high in-
fluent flows.
B. Inadequate pump
ing of setpoint
are "improper.
C. Inadequate pumj
ing if pump is
undersized.
4 . None
5. Inability to
keep up with
incoming flow.
Must be able to
override demand
limiter.
REFKREN^S
Vendor manuals
_
'
-.
-------
PROCESS/ STEP
I. PUMPING:
CONVEYANCE AND
PRIMARY SYSTEMS
I-1
<^
ENERGY USES
Electrical Power for
Motors
INDICATIONS OF
ENERGY
INEFFICIENCIES
1. Rapid Cycling
2. Excessive power/cur-
rent drawn (compared
to design) for flow
produced, or inade-
quate flow.
POTENTIAL
CONSERVATION
MEASURES
LA. Employ sequential
starting.
B. Change liquid level
controller setpoints.
C. Operate equalization
basins or increase
capacity and operate
pumps to shift some
load to off-peak
period .
2A. Investigate blockage,
impeller or bearing
wear, packing tight-
ness, etc.
B. Clean basin, piping,
filters, etc.
C. Redesign piping to
to reduce head 'loss.
COSTS &
SAVINGS
1A. Costs: none
Savings : re-
duced demand
and energy.
B. Costs: correc-
tive main-
tenance Sav-
ings: reduced
demand .
C. Costs: storage
Savings : peak
period elec-
trical con-
sumption.
2A. Costs. -repair.
Savings ; im-
proved per-
formance.
B. Costs :main-
tenance . Sav-
ings: energy .
C. Costs :ripout
and replace-
ment- ^flvlnt^s
energy.
POTENTIAL
IMPACT OH
OPERATIONS
1A. Overflow or
underflow un-
less automated
B. None
. C. Backshift laboi
2A. None
B. None
C. Process inter-
ruption.
REFERENCES
Reference 1
Vendor iranuals, ac
ceptance tests,
reference 2
Reference 1
-------
PROCESS/STEP
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
POTENTIAL
CONSERVATION
MEASURES
COSTS &
SAVINGS
POTENTIAL
IMPACT ON
OPERATIONS
REFERENCES
II. PRELIMINARY
TREATMENT
liT. PRIMARY TREATMENT
Electrical power
for comminutors
and/or screens.
Electric power
for grit removal.
Fuel for grit
disposal.
Electric power for
sludge and skim-
ings collection
and removal.
1. Either excessive
buildup of debris or
excessive debris re-
moval .
2. Efforts to attain
"clean" grit through
washing.
3. Burning for disposal
then hauling.
L. Overpumping of sludge
from settling basins.
1. Adjust timing of
screenings removal.
2. Reduce washing3 to
capture maximum grit.
3. Bury on site.
I. Costs; motor
speed change.
Savings; elec-
trical power.
2 . Costs: none.
Savings;
Electric
Energy.
3. Cost: land
disposal.
Savings: fuel
1. None
2.
Improper con-
trol.
1. Reduce flow by manual
or auto pump shutdown
1.
Coat: reduc-
tion device.
Savings: Elec-
tric Energy.
3, Inadequate odor
control.
1. Inadequate pump
ing.
1. Referen'-" 1
2. Reference 2
Reference 2
-------
PROCESS/ STEP
III. SECONDARY/
TRICKLING
FILTERS
SECONDARY/
ROTATING BIOLOGICAL
CONTRACTORS (RBC)
I-1
CD
ENERGY USES
Electrical power for
reclrculation pumping
(trickling filters).
Electrical power for
media Dotation.
INDICATIONS OF
ENERGY
INEFFICIENCIES
1. See Section I on
pumping.
1, Excessive recircula-
flow beyond process
requirements.
3. Using stone media.
1. Unncessary number
of units In use dur-
ing low flow periods.
POTENTIAL
CONSERVATION
MEASURES
1. See Section I.
2. Reduce recirculation
flow automatically o
manually.
3. Install synthetic
media to Improve
treatment with less
recirculation.
1A. Reduce the number of
RBCs in use manually
or automatically.
B. Reduce the speed of
operating RBCs.
COSTS &
SAVINGS
1. See Section I
2. Cosj^: flow
reduction de-
vice . Savings
Electric
Energy.
3. Cost : new media
purchase and
old media dis-
posal. .Savings
Improved or-
ganic reduc-
tion and re-
duced process-
ing energy.
lA.Cost : none or
auto device.
Savings:
electrical
power.
B. Cost: device
Installation.
Savings:
electrical
power.
POTENTIAL
IMPACT ON
OPERATIONS
1. See Sect-ion I.
2. Inadequate recir
culation during
periods of high
flow.
3. Process Inter-
ruption.
1A. Inadequate
treatment if
additional
units not
started when
flow/solids In-
crease.
B. Inadequate
treatment if
speed not in-
creased as flow/
solids Increase.
REFERENCES
1. See Section I.
2. Reference 1
1
-------
PROCESS/ STEP
III. SECONDARY /RBC
SECONDARY/
ACTIVITATED
SLUDGE
I-1
VD
ENERGY USES
Electrical power for
blowers .
INDICATIONS OF
ENERGY
INEFFICIENCIES
2. Using motor-driven
contactors.
1. No bubbles exiting
diffusers or low DO
in effluent.
2. Unnecessary number
of .units in opera-
tion during low flow
3. Suboptimal BOD remo-
val.
4. High electric demand
charges.
POTENTIAL
CONSERVATION
MEASURES
2. Convert to dif-
fused ,air-driven
contactors.
1. Clear Blockage(clean
diffusers or filters)
2A. Reduce the number of
units operating.
B. Throttle suction
value of remaining
units.
C. Install variable
speed controllers.
3. Optimize process
parameters with res-
pect to treatment anc
energy performance.
4A_ Reduce surges from
startup via staging,
or starting in low-
load periods (nights)
COSTS &
SAVINGS
2. Cost,: retrofit
installation
plus fan
power . Savings
electric power
1. Cost_: mainte-
nance . Pavings :
increased per-
formance.
2A.Cost: none or
device instal-
lation. Sav-
ings ; electri-
cal power.
B. Cos L: none.
Savings :
electrical
power .
C. Costicon-
troller retro-
fit and opera-
tion. Savinesj
electrical
power.
3A. Cost: employ-
ee training
and increased
control mea-
sures.
Savings : re-
duced process-
ing energy .
Benefits:
greater com-
pliance.
It. Costs:none.
Sft vines : IVm.n
POTENTIAL
IMPACT ON
OPERATIONS
2. Insufficient 02
transfer to
support biologi-
cal activity.
1. None.
2A. Inadequate
treatment if
flow increases.
B. Blower surge.
C. Inadequate
treatment if
underdesigned.
3A. Inadequate
organizes re-
moval.
<1 Chnrge
REFERENCES
1. Reference 1.
Reference 1
3A. Reference 1
-------
PROCESS/ STEP
III. SECONDARY/
ACTIVITATED SLUDGI
N>
O
ENERGY USES
Electrical power for
nechanlcal aerators.
INDICATIONS OF
ENERGY
INEFFICIENCIES
5. Excessive air for
treatment requirements
». Excessive nitrifica-
tion.
. Excessive air for
treatment require-
ments.
!. Water level too high
in mechanical aerator.
3. High electric demand
charges.
POTENTIAL
CONSERVATION
MEASURES
4B. Install tlmeclocks
on aerators for diur-
nal variations.
5A. Reduce air distribu-
tion during low flow
periods.
B. Redesign, relocate
system components
for more efficient
oxygen transfer.
6. Reduce Sludge Reten-
tion Time.
1A. Reduce number or speec
of aerators during
low flow.
3. Schedule startups of
mixers and other units
to avoid coincident
surges.
COSTS &
SAVINGS
AB.Cost^: equip-
ment Installa-
tion and oper-
ation. Savings ;
Demand Charge.
5A. Cost: flow
reduction
Savings : power,
B. Cost: system
design, retro-
fit, operation.
Savings : im-
proved perfor-
mance and re-
duced electri-
cal power.
6 . Cost: none .
Savings ; Pro-
cess energy.
lA.Cost :none .
Savings:
electrical.
3 . Costs: none .
Savings: re-
duced elec-
tric demand
charges.
POTENTIAL
IMPACT ON
OPERATIONS
4B. Inadequate
oxygen transfer.
5/\ Inadequate if
air not restored
during high flow.
B. Inadequate 0.
if designed im-
properly , (inade-
quate mixing, In-
complete BOD re-
moval .
6 . Inadequate
organic removal
if overcorrected.
1A-B. Inadequate
0_transfer or
or mixing.
REFERENCES
''B. Reference t>
5A. Reference 1.
J. References 1 &
& 3
6. Reference 7.
IA-D. Reference 1.
-------
PROCESS/STEP
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
POTENTIAL
CONSERVATION
MEASURES
COSTS 6,
SAVINGS
POTENTIAL
IMPACT ON
OPERATIONS
REFERENCES
HI- SECONDARY/
ACTIVITATED
SLUDGE
Electrical power for
oxygen generation.
1. Excess 0- consumption
from open tanks.
B. Reduce speed of
operating aerators.
C. Convert to bubble
dlffuser aeration.
1A. Install tank covers
and Institute auto-
matic feed control.
B. Convert to air-blown
system.
C. Install weir to auto-
matically control
liquid level.
B. Cost:speed
control de-
vice, pavings:
electrical
power.
C. Cosi:retroflt
and operation.
Savings: elec-
trical power.
1A. Cost! tank
fabrication
and feed con-
trol. Savings:
electrical
power.
B.
C.
Cost: new
system retrofl
and operation.
Savings; elec-
trical power
for 02-
Costiwelr In-
stallation.
Savings:
electrical
power .
1A.Either Inade-
quate 0_(lnade-
quate transfer)
or excess 0_(saf
ty hazard) If
designed/opera-
ted Improperly.
B. Inadequate 0»
transfer or
mixing.
A. Reference J
-------
PROCESS/STEP
III. SECONDARY/
ACTIVITATED
SLUDGE
to
N)
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
2. Purchasing \O2 (for
plants larger than
C. 2 Mgd).
POTENTIAL
CONSERVATION
MEASURES
2A. Generate 0- on-site
during off^-peak
hours (provide ade-
quate storage).
B. (Convert
to air-blown system
COSTS &
SAVINGS
2A
Costj 0_ gene-
rator (pres-
sure swing
absorption
or cryogenic)
Benefits:
'power. Sav-
ings :pur-
chased 0_
POTENTIAL
IMPACT ON
OPERATIONS
2A.
Safety hazards
backup 6- if
unit fails.
B.
Cost:new
system re-
trofit and
operation.
Savings:
purchased Q
B. Inadequate
oxygen trans-
fer.
REFERENCES
2.
Reference 1
2. Reference 1
-------
PROCESS/ STEP
SLUDGE/
IV. DIGESTION
N>
U)
ENERGY USES
Electrical power for
blowers and mechani-
cal aeration in aero-
bic digestion.
INDICATIONS OF
ENERGY
INEFFICIENCIES
1A. See Section I on
pumping.
B. See Section III on
activated sludge.
C. Foaming (over-
aeration) , excess
DO.
2. Using batch process
loading and decant-
ting.
3. Inadequate volatile
solids loading
(much less than de-
sign) .
4. Excess VS or low
DO.
5. Using extended
aeration.
POTENTIAL
CONSERVATION
MEASURES
1A. See Section I.
B. See Section III
C. Reduce aeration.
2. Operate feeder pumps
continuously to mini-
mize shocks .
3. Increase volatile
solids concentration
(decrease SRT) .
4. Increase SRT.
5A. Convert to simple
activated sludge.
COSTS &
1A. See Section
I.
B. See Section
III.
C . CostJ none .
Savings ;
electrical
power .
2. Costs:electri-
cal power.
Savings : re-
duced energy
for sludge
handling and
disposal.
3. Cost : none.
gavings : re-
duced process
energy.
4. Costs: none.
Savings :re-
duced pump-
ing power .
Benef its:im-
proved procesi
efficiency.
5A. Caats.: re-
trofit and
operating
labor costs.
Savings :
energy from
aeration.
POTENTIAL
IMPACT ON
OPERATIONS
1A. See Section I.
B. See Section
III.
C. Inadequate Q
transfer or
mixing .
2. None.
3. Excess VS
loading or low
DO.
4. Overcorrection
5A. Improper de-
sign.
REFERENCES
1A. See Section I
1. See Section III
1. Reference 6
2. Reference 6
3. Reference 6
4. Reference 6
5A. Reference 6
-------
INDICATIONS OF POTENTIAL POTENTIAL
PROCESS/STEP
SLUDGE/
IV. DIGESTION
j
°^
ENERGY USES
Raising temperature
for anaerobic diges-
tor .
ENERGY
INEFFICIENCIES
1. Tempera ture>98°F
(mesophilic range) .
2. Widely varying
digester tempera-
tures or vs. con-
trations.
CONSERVATION
MEASURES
5B. Convert to anaero-
bic digestion with
energy recovery.
1. Reduce temperature
by:
A. reducing fuel
combustion.
B. reducing dipjes-
tor gas firing
temperature.
C. reducing waste
heat input.
2. Feed sludge slowly
and continuously
rather than in large
batches.
COSTS &
SAVINGS
5B.. Cost,: Process
conversion
and operation
Savings :
electrical
power and
conventional
fuel purchase
1A. Costs: none.
Savings : Con-
ventional
fuel.
B&C. Costs:
opportu-
nity costs
of waste
heat re-
covery.
Savings:
may use in
other plant
processes .
2. Costs :none.
Savings: heat
input. Bene-
fits :more
complete
sludge pro-
cessing.
IMPACT ON
OPERATIONS
5B. Process inter-
ruption. Non-
compliance if
improperly de-
signed or
operated.
;.
1. Slowed reaction
rates if tem-
perature drops
below 85°F.
2. None
REFERENCES
5B. Reference 5
1. Reference 5
2. Reference 6
-------
PROCESS/ STEP
IV. SLUDGE/
DIGESTION
S3
i_n
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
3. Improper sludge
loading.
It. Leaking seals, cracks
In walls, etc.
5. Inefficient heat
transfer in digester
heat exchanger.
6. Uninsulated tank
roof.
7. Underinsulated tank
walls (cold climate)
8. Using low rate di-
gestion.
9. Flaring or otherwise
not recovering di-
gester gas.
POTENTIAL
CONSERVATION
MEASURES
3. Restore volatile
solids (VS) concen-
trate to 0.03 to 0.1
Ib VS per cubic foot
per day.
A. Repair
5. Clean surfaces.
6. Insulate with thick-
ness recommended for
region.
7. Add insulation
to achieve thickness
recommended for re-
gion.
8. Convert to high rate
digestion (0.3 Ib vs
cubic foot per dayl
9. Recover digester gas
and use for:
A. digester heating
B. sale
C. electricity
generation
COSTS &
SAVINGS
3. Costs :pumping
power . Savings :
heat input.
4. Cost: repair
labor and
supplies.
Savings: heat.
5. Cos^ mainten-
ance. Savings:
heat input.
6. Cost :materials
and installa-
tion. Savings:
heat input .
7. Cosjt:materials
and installa-
tion. Savings:
heat input .
8. £os_t: conver-
sion and
operation cost
gflv^ngg: pro-
cess energy.
9 . Cost: equip-
ment con-
struction and
operation.
Savings : con-
ventional
fuel.
POTENTIAL
IMPACT ON
OPERATIONS
3. None
4 . None
5. None
6 . None
7. None
8. Inadequate
processing if
designed or
operated im-
properly.
9. Need for
supplemental
energy if im-
properly de-
signed.
REFERENCES
3. Reference 6
4. Reference 6
5. Reference 2
8. Reference 6
9. Reference 5
D. plant heating
-------
PROCESS/STEP
V. SLUDGE/TREATMENT &
CONDITIONING
N>
O^
ENERGY USES
Fuel for heat treat-
ment (thermal con-
ditioning
INDICATIONS OF
ENERGY
INEFFICIENCIES
1. High temperatures
relative to design.
2. Excess air greater
than design.
3. Operating batch
process with many start-
ups and shutdowns.
4. Using afterburner
to destroy odors.
5. Not using waste
heat.
6. Not using treated
sludge to supplement
conventional fuel.
7. Not using lower net
energy process.
POTENTIAL
CONSERVATION
MEASURES
1. Reduce steam consump-
tion (fuel firing rate)
to reduce temperatures
to lowest practical.
2A. Shutdown unnecessary
blowers.
2B. Throttle flow.
3. Operate continuous
or semi-continuous
process.
4. Discharge off gases
through secondary treat-
ment tanks.
5A. Install economizer
to pre-dry sludge.
5B. Recover waste heat
to supplement building
or process heat.
6. Fire sludge for part
of the energy require-
ments.
7. Convert to anaerobic
digestion with heat
recovery.
COSTS &
SAVINGS
1. Costs: None.
Savings ; Fuel.
2. JJos t8 : None.
Savings ; Electri-
cal power.
3. Coats: Back-
shift labor.
Savings : Conven-
tional fuel for
startup.
4. Costa: Equip-
ment reconfig-
uration.
Savings ; Conven-
tional fuel.
5A&B. Costs;
Equipment install
atlon. Savings :
Conventional fuel
6. Costs: Sludge
handling and
conveying.
Savings: Conven-
tional fuel.
7. Costa; Equip-
ment design, and
construction, am
operation.
pavings : Conven-
tional fuel.
POTENTIAL
IMPACT ON
OPERATIONS
1. Incomplete
conditioning if
temperatures re-
duced too much.
2. Incomplete
conditioning if ai
reduced too much.
3. None
4. Air quality
constraints.
5A&B. None
6. Air quality
constraints.
7. Inadequate pro-
cessing if designei
or operated
Improperly.
REFERENCES
1. Reference 6
2. Reference 6
3. Reference 6
4. Reference 4
5. Reference 6
6. Reference 6
7. Reference 6
-------
PROCESS/STEP
V. SLUDGE /TREATMENT &
CONDITIONING (Cont.)
N5
--J
ENERGY USES
Pumping during
thickening.
Fan power for vacuum
filtration.
Electrical
INDICATIONS OF
ENERGY
INEFFICIENCIES
1. See section I on
pumping.
2. See section II on
sedimentation.
3. Large number of fre-
quent) dewaterings.
4. Using froth flotation
year round.
1. Low sludge content in
fuel.
2. Suboptimal machine
variables.
3. Plugged filter media.
4. Not using low energy
processes.
1. Excessive water in
the sludge cuter.
POTENTIAL
CONSERVATION
' MEASURES
3A. Reduce number of de-
watering periods to
minimum practical.
3B. Thicken in primary
sedimentation tanks.
. . Increase sludge
concentration.
2. Restore drum speed,
submergence depth, and
vacuum to design condi-
tions.
3A. Clean filter.
3B. Replace filter with
new media.
4. Convert to drying
bed or belt process.
LA. Reduce conveyor speed.
LB. Increase bowl
speed.
COSTS &
SAVINGS
1. Costs: Storage
:avings : Electri-
cal power .
IB. Costs: None.
avinfis : Electric
>ower .
.. Costs: Upstream
Costs . Benefits:
;reater cake
rormation for the
energy used.
2. Costs: Mainte-
nance. Benefits:
greater cake for-
nation for the
>nergy used.
}A. Costs: Main-
:enance. Savings;
Slectrical power.
}B. nngt-s: Filter.
layings ; Electri-
cal power.
i. Costs: Equip-
nent configuration
ind operation.
Savings : Electri-
cal power.
-A. Costs: None
.B. Costs: Electr-
.cal power.
LA&B. Benefits:
Jreater solids re-
:overy and dryer
cake requiring
Less energy in
subsequent pro-
cess phases.
POTENTIAL
IMPACT ON
OPERATIONS
3A&B. Incomplete
dewatering if not
monitored.
1. Longer
times , increased
chemical usage.
2. None
3. None
4. Incomplete de-
watering.
1A&B. Low solids
recovery if over-
corrected.
REFERENCES
3. References 2&4
1. Reference
6
2. Reference 7
3. Reference 4
4. Reference 1
1. Reference 6
-------
PROCESS/STEP
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
POTENTIAL
CONSERVATION
MEASURES
COSTS &
SAVINGS
POTENTIAL
IMPACT ON
OPERATIONS
REFtRENCES
V. SLUDGE/TREATMENT &
CONDITIONING (Cont.)
Electrical power
for filter press.
1. Excessive blinding.
1A. Precoat with incin-
erator ash or polymer.
IB. Replace with mono-
filament media.
1A. ^osts: Chemi-
cals. Savings:
Dryer solids re-
quiring less sub-
sequent energy.
IB. Costa: Media
replacement.
Savings: Greater
cake recovery and
dryer solids.
1A. None
IB. Improper design
1A. Reference 6
IB. Reference 6
00
-------
PROCESS/ STEP
VI. ;;i, HUGE/DISPOSAL
to
3
ENERGY USES
1. Pilot fuel for
incineration.
2. Fan power for In-
cineration.
3. Electrical power
for pollution con-
trol equipment for
incineration.
INDICATIONS OF
ENERGY
INEFFICIENCIES
1 . Excessive use (
10 to 20% of total
Btus) or high tempera-
ture.
1. Excess air over that
required for complete
combustion (high 0.
concentration in
stack) .
1 . Excessive pressure
drop or current (e.g.
precipitator) compared
to design.
POTENTIAL
CONSERVATION
MEASURES
1A. Reduce the amount
used for flame
stabilization.
IB. Install economizer to
predry sludge.
1C. Go to semi-continuous
operation. Extinguish
pilot flame during
extended shutdown.
1. Reduce fan power
(e.g. secure one
unit).
2. Install automatic 0_
analysls to control
air flow.
1. Clean surfaces.
COSTS &
SAVINGS
lA-Ugg^s,: none.
Savings : pur-
chased fuel.
IB. Cost -.design.
procurement,
and installa-
tion. Savings :
fuel.
1C. Cost; addition
al supervisory
labor.
1 . Costs: none .
Savings: fan
power.
2. Costs: equip-
ment and run-
ning expenses.
Sayings : fan
power .
1. Costs: main-
tainance.
Savings: elec-
trical power.
Benefits: im-
proved perfor-
mance .
POTENTIAL
IMPACT ON
OPERATIONS
1A. Temperatures too
low to destroy
odors, or unsta-
ble flame.
IB. None
1C. Must ensure gas
flow completely
shutoff to pre-
vent subsequent
explosion.
1. Inadequate air
flow.
2. None
1. None.
REFERENCES
1. Reference 1
1C. Reference 1
Vendor manual ,
acceptance tests.
Vendor manuals
-------
PROCESS/ STEP
VI. SLUDGE/ DISPOSAL
Co
0
ENERGY USES
4. Incineration heat
losses up the
stack or into
cooling water.
INDICATIONS OF
ENERGY
INEFFICIENCIES
1. No recovery.
2. Not integrated with
other plant chemical
processes requiring
heat/steam.
3. Not integrated with
anaerobic digestion
or heat treatment.
POTENTIAL
CONSERVATION
MEASURES
2. Reduce induced
draft fan power.
1. Consider recovery and
use for building
space heating or
process.
2. Consider lime recal-
cining recovery, ac-
tivated carbon re-
generation, or
ammonia stripping
with steam.
3A. Consider heat re-
covery to sustain
anaerobic digestion
or heat treatment
with only supple-
mental fuel purchases
3B; Consider converting
to composting.
COSTS &
SAVINGS
2 . Coat: none .
Savings : elec-
trical power.
1. Cjistg.: design,
procurement ,
installation,
and operation
Savings: pur-
chased fuel
or electricity
2. Costs :equip-
ment, installa
tion and
operation.
Saving^: pur-
chased fuels,
steam or
chemicals.
3 A. ggs_ts.: equip-
ment, in-
stallation.
gajringg : pur-
chased fuel.
IB. Costg: equip-
ment . Bene-
fits: Revenues
from compost
sales and
savings from
reduced ash
hauling and
pollution
control ex-
pense.
POTENTIAL
IMPACT ON
OPERATIONS
2 . Inadequate
pollutant re-
moval rates .
1. Inadequate spac
conditioning or
gas utilization
if poorly de-
signed.
2. Inadequate
chemical re-
covery .
3A. Inadequate pro-
cessing.
3B- Unsaleable
products.
REFERENCES
Acceptance tests
2. Reference 5
3. References 1 &
5
-------
PROCESS/STEP
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
POTENTIAL
CONSERVATION
MEASURES
COSTS &
SAVINGS
POTENTIAL
IMPACT ON
OPERATIONS
REFERENCES
VI. SLUDGE/DISPOSAL
Transportation to
landfill
1. Excessive number of
trips.
2. Long hauls-
3. Poor vehicle fuel
mileage.
A. Truck transport to
adjacent landfill.
Co
1A. Run only full loads.
IB. Concentrate/dewater
solids further.
2. Review shorter hauls
(e.g. to nearby parks or
farms).
3A. Maintain vehicles in
good running condition.
3B. Replace old small
units with new efficient
large models.
Install pipeline if
distance i9 short and flow
is continuous.
1A. Costa; None.
Savings: Fuel.
IB. .COHI-H: Pro-
cess energy.
Savings: Trans-
portation fuel.
2. Costs: None.
Savings: Fuel.
3A. Costa: Main-
tenance. Savings
Fuel.
3B. Costs: Vehi-
cle replacement.
Savings: Fuel.
i. Costs; Pipe-
line design,
laying & opera-
tion. Savings:
Fuel.
1. None
2. Trace elements
(e.g. heavy metals)
may make this
option impractical.
3. None
4. None
Reference 1
Reference 8
-------
PROCESS/ STEP
VII. BUILDINGS
LJ
to .
1
ENERGY USES
1. Lighting.
2. Space condition-
ing.
INDICATIONS OF
ENERGY
INEFFICIENCIES
1. Excess lighting levels
2. Incandescent or other
inefficient bulbs.
1 . Poor housekeeping
(open doors, extended.
air conditioning) .
2. Not taking advantage
of passive solar.
3. Excessive amount of
ventilation.
it. Not taking advantage
of waste heat.
POTENT IAL
CONSERVATION
MEASURES
1A. Turn off lights in
unoccupied spaces and
at end of working day
IB. Reduce levels by re-
moving bulbs.
1C. Clean bulbs and fix-
tures to minimize the
the need for addi-
tional bulbs.
2. Replace outdoor light-
ing with sodium vapor,
Indoor with high effi-
ciency fluorescent.
1A. Indoctrinate plant
staff.
IB. Zone building with
thermostat.
2. Retrofit passive solai
applications (various)
3. Reduce air flow to
minimum practical.
4A. Supplement building
heat with Incinceratoi
or thermal condition-
Ing waste heat.
COSTS &
SAVINGS
1A&B. Costs: none.
Savings:
power .
1C. Costs: Main-
tenance.
Savings :
electrical
power .
2. Costs: light
Savings : elec-
trical?
1. Cost: staff
training &
equipment.
Savings: buil-
ding energy.
2. Cost: retrofit
jSavJLng^:
purchased fuel
3. Cost: none.
Savings: pur-
chased fuel
and recovered
energy.
4A. Cost; equip-
ment reconfig-
uration.
Sav_ings^: con-
ventional fuel
POTENTIAL
IMPACT ON
OPERATIONS
1A. None
IB. Inadequate
lighting.
1C. None
2. None
1 . None
.2. None
). Inadequate ven-
tilation.
i . None
REFERENCES
Reference 4
ieference 4
Reference 4
ieference 4
ieference 4
-------
1'KOCKSS/STEP
VII. BUILDINGS
Lo
W
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
5. Firing conventional
fuels.
1. Firing conventional
fuels or using elec-
tricity.
POTENTIAL
CONSERVATION
MEASURES
4B. If process plant al-
ready uses steam,
install steam absorp-
tion chillers.
5A. Use water-to-air or
water-to-water heat
pumps on plant efflu-
ent.
5B. Recover process plant
energy (digester gas,
sludge firing, engine
jacket cooling, etc.)
1 . Insulate hot water
heat and piping.
2. Recover heat from
plant processes (en-
gine cooling water,
digester heat, etc.)
3. Install solar panels.
COSTS &
SAVINGS
4B. QOJ!£J equip-
ment install-
ation opera-
tion. Savings
electricity.
5A. Cost: equip-
ment install-
ation and
operation.
Savings : con-
ventional fue:
5B. Total cost of
energy reco-
very versus
displacement
of convention-
al fuels.
1 . Cost: insula-
tion. Ravines;
energy.
2. Cost: system
design instal-
lation & oper-
ation ._S a vines :
conventional
fuel/electri-
city .
3. Cost: system
installation,
operation &
maintenance.
Savings: con-
ventional fuel/
eletricity .
POTENTIAL
IMPACT ON
OPERATIONS
5. Process suboptl^
mization.
1 . None
2. Improper temper-
atures.
3. Improper temper-
atures.
REFERENCES
Reference 1
-------
PROCESS/STEP
ENERGY USES
INDICATIONS OF
ENERGY
INEFFICIENCIES
POTENTIAL
CONSERVATION
MEASURES
COSTS &
SAVINGS
POTENTIAL
IMPACT ON
OPERATIONS
REFERENCES
VIII.MAINTENANCE EQUIP-
MENT & INSTRUMENTA-
TION
IX. ELECTRIC LOAD
MANAGEMENT
Demand component
of electric billing
.. Overdue calibrations
or other tests.
2. Failed meters and
auges.
3. Informal maintenance
practices.
1. Excessive demand
charges in relation
to rated loads of
pumps, blowers, etc.
Perform checks as
required. Repair as
necessary.
2. Repair
3. Install formal
preventive maintenance.
1. a) Overall start/stop
scheduling for
pumps, blowers,
mixers, etc. to
avoid coincident
surges.
b) Deferral of
influent pumping
via equalization
basins to avoid
peak demand periods
c) Deferral of solids
processing until
off-peak periods.
1&2. posts: Main-
tenance. Savings
Identify impro-
perly functioning
equipment.
3. Costs; Main-
tenance labor
and meterial.
Savings: Improved
equipment per-
formance.
1. Costs: None
Savings:
reduced demand
charges.
1. None
2. None
3. None
1. None
-------
REFERENCES
1. Aeration in Wastewater Treatment Plants, MOP-5, Water Pollution Control
Federation, 1971.
2. Energy Conservation in the Design and Operation of Wastewater Treatment
Facilities, Water Pollution Control Federation, 1981.
3. Energy Conservation in Municipal Wastewater Treatment, U.S. EPA, 430/
9-77-011, March 1978.
4. Management of Small to Medium-Sized Treatment Plants, U.S. EPA, 430/
9-79-013.
5. Operation of Wastewater Treatment Plants, MOP-11, Water Pollution Control
Federation, 1975.
6. "ProcessesNot ProductsBiggest Energy Saving Factors," Water and Sewage
Works, November 1980.
7. "Selecting Pipelines to Achieve Effective Energy Conservation," A. Reid,
Water and Sewage Works, November 1980.
8. Wastewater Treatment Plant Design, MOP-8, Water Pollution Control Federa-
tion, 1977.
9. Energy Conservation at Wastewater Treatment Plants, a Special Publication
of the Technical Practice Committee, SPCF, 1980.
10. Life Cycle Costing Emphasizing Energy Conservation, by the Energy Research
and Development Administration, (Department of Energy), May 1977.
11- Proceedings of the U.S Department of Energy, Energy Optimization of Water
and Wastewater ManagementforMunicipaland"IndustrialApplications
Conference, 1979.
35
. S . GOVERNMENT PRINTING OFFICEs 1982-361-082/308
-------
-------
United States
Environmental Protection Agency
Publications Distribution Center
531 - North Wayne Avenue
Cincinnati, OH 45215
Official Business Special
Penalty for Private Use $300 Fourth-Class
Rate
Book
------- |