Metropolitan Water Reclamation District of Greater Chicago
IEPA ATTACHMENT NO.t....Q.
BOARD OF COMMISSIONERS
Terrence J. O'Brien'
President
Kathleen Therese Meany
Vice President
Gloria Alin° Majewski
Chairman
of
Finance
Frank Avila
Patricia Horton
Barbara J. McGowan
Cynthia M. Santos
Debra Shore
100 EAST ERIE STREET?
CHICAGO, ILLINOIS 60611-3154?
312.751.5600
?
Patricia Young
Richard Lanyon
General
Superintendent
January
23, 2007
312-751-7900?
FAX 312.751.5681
Mr. Toby Frevert, Manager
Division of Water Pollution Control
Bureau of Water
Illinois Environmental Protection Agency
1021 North Grand Avenue East
P.O. Box 19276
Springfield, Illinois 62794-9276
Dear Mr. Frevert:
Subject: Evaluation of Management Alternatives for the Chicago Area
Waterways: Investigation of Technologies for Supplemental
Aeration of the North and South Branches of the Chicago River,
Flow
Augmentation of the Upper North Shore Channel, and Flow
Augmentation and Supplemental Aeration of the South Fork of the
South Branch of the Chicago River
The Metropolitan Water Reclamation District of Greater Chicago, at the
request of the Illinois Environmental Protection Agency (IEPA), hereby
submits the enclosed, reports entitled "Technical Memorandum 4WQ:
Supplemental Aeration of the North and South Branches of the Chicago
River", "Technical Memorandum SWQ: Flow Augmentation of the Upper North
Shore Channel", and "Technical Memorandum 6WQ: Flow Augmentation and
Supplemental Aeration of the South Fork of the South Branch of the
Chicago River."
Using the services of Consoer Townsend Envirodyne Engineers, Inc., these
reports have been developed to evaluate technologies and costs for
Supplemental Aeration of the North and South Branches of the Chicago
River, Flow Augmentation of the Upper North Shore Channel, and Flow
Augmentation and Supplemental Aeration of the South Fork of the South
Branch of the Chicago River.
If you have any questions, please contact Mr. Lou Kollias at (312) 751-
5190.
Very truly yours,
VNI--
Richard Lanyon U
General Superintendent
JS:TK
Attachments
CC:
?
L. Kollias, MWRD
R. Sulski, IEPA
FINAL 01/12/07
TECHNICAL MEMORANDUM 4WQ
SUPPLEMENTAL AERATION OF THE NORTH AND
SOUTH BRANCHES OF THE CHICAGO RIVER
METROPOLITAN WATER RECLAMATION DISTRICT OF
GREATER CHICAGO
NORTH SIDE WATER RECLAMATION PLANT AND SURROUNDING
CHICAGO WATERWAYS
Submitted by:
CTE AECOM
Revision 4 – January 12, 2007
MWRDGC Project No. 04-014-2P
CTE Project No. 40779
FINAL 01/12/07
TABLE OF CONTENTS
INTRODUCTION ?
4-1
Background
?
4-1
Objective and Scope of Study
?
4-2
Waterway Target Dissolved Oxygen Standards
?
4-4
Chronology of Past Supplemental Aeration Studies
?
4-4
Waterway Modeling of Supplemental Aeration
?
4-6
Supplemental Aeration Modeling Runs
?
4-6
LONG LIST OF TECHNOLOGIES
?
4-10
EVALUATION ?
4-21
Advantages and Disadvantages of Technologies
?
4-21
Air Diffusion Systems
?
4-21
Head Loss Structures
?
4-22
Mechanical Surface Aerators
?
4-23
U-Tube Aerator Systems
?
4-23
High Purity Oxygen Systems
?
4-23
Screw Pumps
?
4-24
Scoring of Qualitative Economic and Non-Economic Criteria Matrix ...
4-24
Life Cycle Costs ?
4-25
Maintainability ?
4-29
Operability
?
4-29
Reliability?
4-29
Energy Efficiency
?
4-30
Impacts on Neighbors
?
4-30
Expandability
?
4-30
Short List of Technologies
?
4-31
4-i
FINAL 01/12/07
Land Availability for Supplemental Aeration
?
4-31
Cost of Supplemental Aeration Stations
?
4-38
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
?
4-39
FINAL 01/12/07
LIST OF TABLES
Table 4.1?
Air Diffusion Systems – Advantages and Disadvantages
?
4-22
Table 4.2?
Head Loss Structures – Advantages and Disadvantages
?
4-22
Table 4.3?
Mechanical Surface Aerators–Advantages and
Disadvantages
?
4-23
Table 4.4?
Compressed Air U-Tube Contactors – Advantages and
Disadvantages
?
4-23
Table 4.5?
High Purity Oxygen – Advantages and Disadvantages
?
4-24
Table 4.6?
Evaluation Matrix
?
4-27
Table
4.7?
Summary of Capital and Annual Costs
?
4-39
FINAL 01/12/07
LIST OF FIGURES
Figure 4.1
?
The Chicago Area Waterways
?
4-3
Figure 4.2
?
Supplemental Aeration of North and South Branches of Chicago
River Percent of Hours Complying with 5 mg/I Criterion,
All Time Periods
?
4-8
Figure 4.3
?
Proposed Aeration Station Sites
?
4-9
Figure 4.4
?
Schematic Diagram of Devon Avenue Instream
Aeration Station
?
4-12
Figure 4.5
?
Schematic of Jet Aeration System
?
4-13
Figure 4.6?
Schematic of 3-Step Free Fall Weir Supplemental
Aeration System
?
4-14
Figure 4.7?
Mechanical Surface Aerator
?
4-16
Figure
4.8?
Schematic of Compressed Air U-Tube Contactor
?
4-17
Figure 4.9
?
Schematic of Pressurized HPO Contactor
?
4-19
Figure 4.10 Barge Mounted HPO Diffuser System
?
4-20
Figure 4.11 80 g/s (Oxygen) SEPA Station Conceptual Layout
?
4-33
Figure 4.12 80 g/s (Oxygen) Jet Aeration Station Conceptual Layout
?
4-35
Figure 4.13 80 g/s (Oxygen) Ceramic Fine Bubble Diffuser Station
Conceptual Design
?
4-36
Figure 4.14 80 g/s (Oxygen) Compressed Air U-Tube Station Conceptual
Design
?
4-37
FINAL 01/12/07
APPENDICES
Appendix A Unit Costs Used in Cost Estimates
Appendix B Detailed Capital Cost Estimates for Four Short-Listed Technologies
Table B-1 through B-5
Appendix C Detailed Annual Cost Estimates for Four Short-Listed Technologies
Table C-1 through C-8
Appendix D Figures Showing Land Availability for Four Supplemental Aeration
Stations
Figures D1 through D4
FINAL 01/12/07
SUPPLEMENTAL AERATION OF THE NORTH AND
SOUTH BRANCHES OF THE CHICAGO RIVER
(TM-4WQ)
INTRODUCTION
Background
Consoer Townsend Envirodyne Engineers, Inc. (CTE) was retained in 2005 by the Metropolitan
Water Reclamation District of Greater Chicago (MWRDGC) to provide engineering services to
prepare a comprehensive Infrastructure and Process Needs. Feasibility Study (Feasibility Study)
for the North Side Water Reclamation Plant (WRP). As part of the scope of work for the
Feasibility Study, CTE was directed to determine the technologies and costs of water quality
management options which originated from the on-going Use Attainability Analysis (UAA) being
conducted by the Illinois Environmental Protection Agency (IEPA) of the Chicago Area
Waterways (CAWs). The CAWs are shown in Figure 4.1.
This report presents the results of a
study of one of the water quality management options that
originated from the UAA, namely supplemental aeration of the North and South Branches of the
Chicago River (NBCR and SBCR, respectively). The principal objective for this supplemental
aeration study is to improve the dissolved oxygen concentrations in the NBCR and SBCR.
Supplemental aeration of the NBCR and SBCR is among several water quality management
options studied by CTE. Other water quality management options are discussed in separate
reports. These reports are not designed to determine which (if any) of the water quality
management options should be implemented. Such a determination can only be made by
conducting a comparison of the costs and benefits of all the management options and then
developing a water quality management plan which combines the most cost effective option into
an integrated strategy for improving water quality of the CAWs. Such an integrated study has
not been developed at this time.
UAA Process
The Clean Water Act requires the states to periodically review the uses of waterways to
determine if changes to the existing water quality standards are needed to support a change in
use. Based upon a study of the CAWs, the IEPA had decided that a change may be required in
the dissolved oxygen (DO) standards for these waterways.
As part of the UAA the IEPA suggested several water quality management options for improving
the DO of the CAWs and asked that the MWRDGC determine the technologies and costs for
these options. One of the options that was suggested by the IEPA was supplemental aeration
of NBCR and SBCR.
FINAL 01/12/07
Supplemental Aeration
Supplemental aeration is a water quality management option which has the potential for
improving the DO of NBCR and SBCR. This option was studied in this report.
Supplemental aeration is already being practiced in the CAWs by the MWRDGC. Two
supplemental aeration stations exist on the North Shore Cannel (NSC) and the North Branch of
the Chicago River (NBCR) at Devon and Webster Avenues, respectively. These stations
provide aeration by means of porous ceramic diffusers at the bottom of the waterway. The
diffusers are supplied with air from an on-shore blower facility at each station. Along the Little
Calumet River, Calumet River and Cal-Sag Channel waterways, the MWRDGC has five
supplemental aeration stations utilizing sidestream aeration where low lift pumps remove a
portion of the flow from the waterway and aerate this flow using a free-fall weir system which
subsequently returns the flow back to the waterway.
Objective and Scope of Study
As noted above, the IEPA requested that the MWRDGC study the potential technologies,
opinion of probable costs and impacts for supplemental aeration of the NBCR and SBCR. The
objective of this study was to determine the potential supplemental aeration technologies and
opinion of probable costs to achieve possible future regulatory dissolved oxygen (DO) levels for
these waterways.
CTE developed a long list of supplemental aeration alternatives. Using an evaluation matrix
based upon criteria fromTM-1 and input from the MWRDGC, CTE then prepared a short list of
potential supplemental aeration alternative technologies.
Based upon simulation runs using the Marquette University model, the aeration capacity and
location of supplemental aeration stations needed to supplement the dissolved oxygen in the
NBCR and the SBCR was determined. For each short listed alternative, CTE then prepared a
conceptual layout and cost estimate for the aeration stations determined from the Marquette
Model.
The MWRDGC did not intend this study to reach a conclusion regarding the best supplemental
aeration technology for implementation or to provide design criteria of a supplemental aeration
system for the NBCR and SBCR. Therefore, CTE prepared a short list of potential technologies
and estimated the costs to illustrate the potential range of expenditures for supplemental
aeration of the SBCR and NBCR. The cost estimates are planning level opinion of probable
costs with a potential variation of + 30 percent.
This study also was not intended to reach a conclusion as to whether supplemental aeration of
the NBCR and SBCR should be implemented. Such a decision should be reached only after
integrated study of all IEPA requested water quality management options is conducted. This
study would determine the relative costs and benefits of these options and then determine their
priority for potential implementation. Such an integrated study is beyond the scope of this
Technical Memorandum.
Chicago Area
Waterways
Simpson Street
Main
Linden
StreetStreet ?
-------
NORTH SIDE WRP
LAKE MICHIGAN
rat
BRrI^;
0'.'.
0A
Jackson Boulevard
Cicero Avenue
STICKNEY
----\---Addison Street
Fullerton Avenue
--Division Street
0 •?
- Kinzie Street
Michigan
,V
Avenue
- Clark
.
Street
Romeoville _
Road?
104th Avenue'
JeffersonStreet
?
?
Southwest
River
Highway/Mile
311.7 '/
?
/
/
/?
/
i
Halsted
Joliet
Cicero Avenue?
/
?
/
?
?
LITTLE
Street
i
---,?
Kedzie Avenue '/?
//Ashland
CALUMET
?
Conrail
•,04atefv.w:
Division Street Avenue
RIVER
?RR
Kik
B8s0 RR ---,
Esx 1
-1
• ,
Bubbly Creek
A. $''
?
36th?
\i•
' ./?
Street
?
Racine
Pump StationAvenue,
t?
00
01'
-4`.----
C
Route 83
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I
CALUMET?
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,
il,aek 10114
Torrence
l
i. Avenue
130th
Route 83
Street
Mile 302.6
FINAL 01/12/07
Figure 4.1 — The Chicago Area Waterways
FINAL 01/12/07
Waterway Target Dissolved Oxygen Standards
The IEPA has not yet made a decision as to the dissolved oxygen standards for the NBCR and
SBCR. However for the purposes of this supplemental aeration study of the NBCR and SBCR,
it was necessary to assume a target dissolved oxygen standard.
After discussions with the MWRDGC, it was concluded that the target dissolved oxygen water
quality standard would be 5 mg/I. Because of the highly variable nature of the NBCR and SBCR
due to wet weather flows, etc., it was decided that 90% compliance with the 5 mg/I standard
would be reasonable. Thus, this is the regulatory target used to determine the size and location
of supplemental aeration of the NBCR and SCBR. The model was used to locate and size the
station needed in addition to the existing MWRDGC station at Devon and Webster Avenues.
It should be stated here that the DO regulatory target should not be considered to be a
recommendation of the MWRDGC for the NBCR and SBCR. This target was chosen because it
is necessary to have a target hi order to determine the size and location of supplemental
aeration stations on the SBCR and NBCR. It may well be that a lower standard will be
protective of the SBCR and NBCR. It is hoped however that the IEPA will recognize that it is
virtually impossible to meet a standard 100 percent of the time. Thus a standard which requires
less than 100% compliance should be considered in the UAA process as was done in this
report.
Chronology of Past Supplemental Aeration Studies
The MWRDGC has been at the forefront of the development and the implementation of
innovative concepts to improve wastewater treatment and instream water quality since its
inception over a hundred years ago. Consequently, not surprisingly, it has been a leader in
developing systems and methods for improving instream dissolved oxygen levels via
supplemental aeration. During 1914, the MWRDGC studied the feasibility of aerating a portion
of the Sanitary and Ship Canal (SSC) flow in galvanized steel tanks and returning it to the
waterway. The objective was to determine if the oxygen returned to the canal satisfied an
equivalent amount of dissolved biochemical oxygen demand (BOD). The results were
inconclusive.
In 1921, a small-scale study was performed by the MWRDGC where Chicago River water was
aerated in 100 gallon vitrified tile tanks, indicating that the stream BOD could be satisfied when
DO levels near saturation were achieved. Continuing along these experimental lines, tests were
conducted by the MWRDGC during. 1923 in a wooden tank using air blowers and bottom
diffusers. The results of this pilot study were positive. This led to a full-scale instream study.
During 1924, an old boat lock (137 feet by 22 feet) at the Lockport power dam was deemed
equivalent to a full-scale channel section of water and appropriate for use. Studies considering
the effects of water temperature, aeration times, and types and combination of diffuser plates on
dissolved oxygen uptake rates were conducted.
The interest in developing techniques and/or methodologies, for achieving supplemental
instream aeration by the MWRDGC was reborn in the mid 1950s. During this time, an
engineering study was conducted to determine the feasibility of using hydro-turbine aeration
(turbine venting) at the Lockport power dam to supply DO to the depleted DO in the waters
upstream of the dam as these waters pass through the penstocks and turbines. A conclusion
was reached that it was not economically feasible to do so because compressed air would be
needed to entrain air into the draft tubes below the turbine runners.
4-4
FINAL 01/12/07
However, in lieu of the less than encouraging results of the turbine venting evaluations
conducted in the mid 1950s, other instream aeration methods were considered for use for
supplementing the DO in the waters immediately above Lockport. A 1958 report published by
the MWRDGC considered using diffused air distributed by porous plates laid on the bottom of
the Sanitary and Ship Canal.
A full-scale, instream study was conducted by the MWRDGC in 1963 using two commercially
available surface mechanical aerators. The aerators were placed in the forebay above the
Lockport dam. The aerators added significant DO poundage to the canal water, but the
conclusions were ambiguous as evidenced by the following quote from the report:
"Engineering studies as to optimum staging of aerators in a waterway system to
cope with existing pollution loads would be of value in comparing costs for
different techniques of aeration."
During the 1960s and 1970s, the United States Environmental Protection Agency (USEPA) (or
precursors) discouraged the use of supplementing instream DO via artificial methods. On April
5, 1977 the General Counsel for the USEPA ruled on a request from the Deputy Assistant
Administrator for Water Enforcement entitled "Use of In-stream Mechanical Aerator to Meet
Water Quality Standards". This ruling was adamantly against supplemental aeration as quoted
below:
"In-stream aerators should not be recognized as being analogous to low flow
augmentation. Therefore, the Office of Enforcement recommends that the use of
these aerators as means of achieving water quality standards following Best
Available Treatment (BAT) be denied."
However, the State of Illinois viewed the situation quite differently. On August 29, 1972, the
Illinois Pollution Control Board (IPCB) acted upon a three part petition submitted by the
MWRDGC on May 3, 1972. Part III requested approval to install instream aerators in the North
Shore Channel and North Branch of the Chicago River waterways. The board ruled favorably
(by a 5-0 vote) as follows:
"The MWRDGC's statement mentions its Board of Trustees action of April 29,
1972 authorizing a $1,500,000 instream aeration system for the North Shore
Channel to be operative by April 1, 1974
?
Instream aeration has been shown to
be perhaps three to five times cheaper than higher treatment....and can be
installed quickly
?
We urge the instream aeration system be completed as soon
as possible."
Consequently, to maintain-stream DO levels at or above applicable standards, the MWRDGC
adopted an instream aeration implementation program in 1975. This led to the installation of the
diffused air system at Devon Avenue, which started operation on February 8, 1979, and at
Webster Avenue, which started operating, on June 6, 1980. They have been operating on a
seasonal basis since.
The MWRDGC also concluded that DO supplementation was needed on the Cal-Sag
Channel/Little Calumet River/Calumet River waterway system. The possible use of methods
other than diffused aeration for supplementing DO along the length of the Cal-Sag waterway
system was explored. One methodology that was considered was the use of side channel weirs
4-5
FINAL 01/12/07
to aerate a portion of the total flow and return it to the main channel. During the summer of
1987 an in-depth weir aeration study was undertaken by the MWRDGC using a full scale pilot
plant located on the banks of the Sanitary and Ship Canal. The experimental results indicated
that water falling freely over stepped weirs produced excellent aeration. Consequently, the
decision was made to install five side stream weir aeration stations along the Cal-Sag waterway
system. The stations are now referred to as SEPA (Sidestream Elevated Pool Aeration) stations
and have provided oxygen supplementation since they went on-line during 1992 and 1993.
Waterway Modeling of Supplemental Aeration
The MWRDGC retained Marquette University to develop a simulation model of the Chicago
Area Waterways including the NBCR and SBCR. This model is described in the report entitled,
"Preliminary Calibration of a Model for Simulation of Water Quality During Unsteady Flow in the
Chicago Waterway System and Proposed Application to Proposed Changes to Navigation
make-Up Diversion Procedures," dated August, 2004. This report was produced by Dr. Charles
Melching from the Institute for Urban Environmental Risk Management at Marquette University
(Milwaukee, Wisconsin).
The Marquette Model was used to determine the aeration capacity and location of supplemental
aeration stations on the NBCR and SBCR. Marquette University conducted various simulation
runs to determine the aeration capacity and location
of
supplemental aeration stations sufficient
to achieve 5 mg/I of dissolved oxygen, 90% of the time in the NBCR and SBCR. Percent
compliance was determined over all time periods simulated in the Marquette Model.
These time periods were:
Year
?
Time Period
2001? July 12 to September 14
2001? September 1 to November 10
2002?
May 1 to August 11
2002? August 10 to September 23
Model simulations in the Marquette Model include overlapping times periods. It is inappropriate
to use overlapping time periods for the evaluation of water quality management options.
Therefore, percent compliance in this report does not include overlapping periods. For this
report, all the results for the July 12 to September 14, 2001 and May 1 to August 11, 2002 times
periods were used, those parts
of
the time periods of September 1 to November 10, 2001 and
August 10 to September 23, 2002 which overlapped with these periods were not used.
For each location in the NBCR and SBCR simulated in the Marquette Model, the percent
compliance was calculated based upon the total number of hours out
of
all time periods that the
hourly dissolved oxygen was at or above 5 mg/I. The percent compliance was based upon the
new stations needed to be added to augment the existing aeration stations at Devon Avenue
and Webster Avenue.
The various modeling runs conducted by Marquette University were based upon discussions
between CTE and University staff prior to the runs. The location and sizing of aeration stations
on the NBCR and SBCR based upon these modeling runs were discussed at a workshop held
with the MWRDGC. The final selected location and sizing of the aeration stations described in
this report represent the results of this workshop
4-6
FINAL 01/12/07
Supplemental Aeration Modeling Runs
The Marquette Model was used to determine the aeration capacity and location of supplemental
aeration stations on the NBCR and SBCR. For these modeling runs, the following conditions
were assumed.
1.
Tunnel and Reservoir (TARP) Tunnels are fully operational
2.
TARP Reservoirs are not on-line.
3.
Other IEPA Requested Water Quality Management Options are not on-line.
4.
The existing Devon and Webster in-stream aeration stations are fully operational
with three blowers assumed to be in service.
Various model simulation runs were conducted. After discussions between Marquette
University, CTE and the MWRDGC, it was agreed that the following supplemental aeration
station locations and aeration capacities represent a reasonable scenario for conceptual cost
estimation.
Waterways
Location (Cross Street)
Required Oxygen Delivery
Capacity
NBCR
Diversey Avenue
30 g/s (5,700/lbs/day)
30 g/s (5,700/lbs/day)
30 g/s (5,700 lbs/day)
NBCR
Chicago Avenue
SBCR
18th Street
SBCR
Halsted Street
80 g/s (15,200 lbs/day)
It should be noted that the 18th
Street Station on the SBCR was originally shown by the
Marquette Model to be located about 1 mile further upstream. But land availability was lacking
at the upstream site. Subsequent model runs showed that the 18th
street location achieved the
water quality target using the same oxygen capacity (5,700 lbs/day) as found necessary for the
upstream site.
This set of supplemental aeration stations achieves a 5 mg/I water quality standard 90 percent
of the time for both the NBCR and SBCR. Figure 4.2 is a graph illustrating the percent
compliance for this set of supplemental aeration stations from the outfall of the North Side WRP
to the junction of the SBCR and the South Fork of the South Branch of the Chicago River
(Bubbly Creek). As shown in Figure 4.2, the percent compliance was calculated for all time
periods simulated in the Marquette Model.
Figure 4.3 shows a map of the Chicago Area Waterways with the locations of the four
supplemental aeration stations as determined by the Marquette model. Also shown in Figure 4.3
are the existing MWRDGC aeration stations at Devon and Webster Avenues.
Division
Jackson
?
Loomis
F
NS: vviRP1
! Addison
100
90
80
70
60
50
40
30
20
10
0
?
1?
I?
I
?
I
?
I
FINAL 01/12/07
4 New Aeration Stations
?
Baseline Condition
47
46 45 44 43 42
41 40 39 38 37 36 36 34 33 32 31 30
River Mile
Figure 4.2 – Supplemental Aeration of North and South Branches of Chicago River, Percent of Hours Complying with 5 mg/I
Criterion, All Time Periods
4-8
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FINAL 01/12/07
Figure 4.3 – Proposed Aeration Station Sites
4-9
FINAL 01/12/07
LONG LIST OF TECHNOLOGIES
Over the past 25 to 30 years, significant advances in supplemental aeration technologies have
been made. Many experts place supplemental aeration methods or procedures into two
categories, namely, aeration and oxygenation.
Aeration is defined as using atmosphere air as the oxygen source; whereas, oxygenation is
defined as using manufactured oxygen gas as the source. Each of the two categories has many
divisions and subdivisions some of which are common to each except for the fact that the
sources of oxygen differ.
The acquiescence by regulatory agencies, starting in the late 1970s, in the use of supplemental
aeration as a means of improving stream water has led to supplemental aeration equipment and
methodologies to be developed and marketed. The object of this section is to explore the
possibilities that are currently available for potential use in solving the DO situations that occur
in the study area.
The range of options available for supplemental aeration technologies is listed below:
I. Pressurized Air Diffusers
A.
Porous Ceramic Diffusers
B.
Membrane Diffusers
C.
Jet Ejectors
II. Head Loss Structures
A. Free Fall Weirs
B. Cascades
III. Mechanical Aerators
IV. U-Tube Bubble Contactors
A. Compressed Air Injection
V. Vaporized High Purity Liquid Oxygen (HPO)
A. Pressurized Water Injection with Diffusers
B. U-Tube Bubble Contactor
C.
Mobile (Barge-Mounted) Dispersion
VI. Screw Pump Aeration
A brief description and discussion of each long list technology will be presented below.
In the sections below, oxygen transfer efficiency (OTE) is defined as the amount of oxygen
actually transferred from the gas phase to the liquid phase as a percentage of the oxygen
supplied in the gas phase.
Pressurized Air Diffusers:
Many instream aeration systems use atmospheric
oxygen supplied by blowers located on shore with the air distributed via instream
diffusers. One major design concern is selecting the proper diffuser system to
4-10
FINAL 01/12/07
meet instream DO needs while being reasonably compatible with the physical
characteristics of a stream.
A.
Fine Bubble Porous Ceramic Diffusers. The MWRDGC's Devon and
Webster Street instream aeration stations consist of blower-induced air
distributed to porous ceramic plates located on the bottom of the North
Branch of the Chicago River as shown in Figure 4.4. The stations have
been operating continuously for about 25 years; however, both have
experienced operation and maintenance problems. Typically these fine
bubble diffuser air systems have an OTE of 10-30 percent.
B.
Membrane Diffusers: Membrane diffuser systems are generally very
flexible and resist fouling due to the following characteristics:
•
The membranes are normally closed until sufficient air pressure
opens the units to begin operation.
•
When the air is interrupted,
,
the membranes close preventing
liquid/solids entry.
•
Membrane diffusers have only an exterior surface phenomena as the
liquid and air interface is at the exterior surface of the membrane
compared to the interior of a ceramic rigid media material.
•
Operation of a membrane unit involves major flexing during on/off
operation with major flexing even during normal airflows. This flexing
tends to minimize the accumulation of surface inorganic materials.
WATER SURFACE?
TOP OF SHEET PILING
DREDGED BOTTOM OF
CHANNEL
FINAL 01/12/07
BLOWER HOUSE
1--
90 FEET
••■•■•■=1
Figure 4.4 — Schematic Diagram
of Devon Avenue Instream Aeration Station
FINAL 01/12/07
•
The surface of some membrane materials is quite smooth and
slick. These smooth, slick surfaces minimize or eliminate calcium
carbonate and other contaminant build-up.
•
Typically membrane diffusers have a OTE of 10-30 percent.
C.
Jet Ejectors.
Jet ejectors mix air and water together using a venturi and
provide a jet of water containing air bubbles. This jet of water creates
good horizontal movement of water over a defined radius or area. Figure
4.5 shows a typical arrangement for a jet aeration system that would
apply to waterway aeration.
The horizontal travel of the plume maintains a gas/liquid transfer interface
for a much longer period of time than conventional diffused aeration
systems. The horizontally mixed plume is enriched with fine bubbles
which will rise slowly to the surface providing for excellent oxygen
absorption. All mixing occurs below the surface eliminating mist and/or
spray problems.
Typically, jet aerators have OTE of 10-25 percent.
\
Figure 4.5 – Schematic of Jet Aeration System
4-13
FINAL 01/12/07
II.
Head Loss Structure.
Head loss structures within the stream or waterway
can result in aeration. The net gain in DO at the structure depends upon the
geometry of the structure versus conditions upstream. Aeration from head loss
structures is usually expressed by an equation relating the DO downstream of
the structure to the DO upstream, saturation DO and a dam aeration
coefficient which is dependent upon the type of head loss structure. The dam
aeration coefficient is expressed per unit length of the structure. Structures with
higher coefficients have higher aeration efficiencies.
A. Free-Fall Weirs.
Sharp-crested, free-fall weirs have clearly been shown to be
excellent aeration devices. Step weirs are a series of free-fall weirs with
each free-fall discharging into a deep pool. Step weir installations can be
used to supplement instream DO, but they must be built on sidestream
diversion channels, similar to the MWRDGC's Cal-Sag waterway SEPA
stations. SEPA stations require access to a significant stretch of land parallel
and adjacent to the waterway.
Figure 4.6 is a schematic of a three-step weir aeration station.
SCREW PUMP FROM WATERWAY
DISCHARGE
TO WATERWAY
Figure 4.6 – Schematic of 3-Step Weir Supplemental Aeration System
4-14
FINAL 01/12/07
B.
Cascades.
Cascades are defined as structures which cause water to rapidly
flow down step inclines in a violent manner without intermittent free-falls
followed by pooling.
Three-step cascades are located on two dams in the Fox River in
Northeastern Illinois. The dam aeration coefficient for these two dams,
determined from extensive field measurements, are 0.65 and 0.72. These
values are only a fraction of the range of values (2.4-4.1) recorded for the 3-
step SEPA facilities on the Cal-Sag Channel.
III.
Mechanical Surface Aerators.
Historically, mechanical aerators have been
classified relative to the axis of rotation, i.e., either horizontal or vertical. These
classifications are further subdivided into surface and submerged types.
Modern innovations, however, have produced hybrid systems that differ from
these simple forms. Virtually all mechanical aerators are designed to mix,
aerate, and facilitate the movement of water, and are quite adaptable for use in
supplementing stream DO. Typically mechanical aerators have an oxygen
transfer rate of 2.0 to 4.0 lbs 02/HP-hr.
Critics of mechanical surface aerators say they provide more mixing than
aeration and that in deep water minimal turnover of the deeper water is achieved.
Moreover, they are vulnerable to damage during high wind, cold weather, high
stream flows and from floating trash. Also, their aeration efficiency can be
reduced when eddy currents and wind move the downstream aerated water
slightly upstream.
Basic surface mechanical aerators have been in use for over 60 years. The
MWRDGC's instream aeration studies conducted during warm weather
conditions above the Lockport dam during 1926 and 1963 used a Yeoman's
Brothers Company HiCoWave Aerator. In the U.S., the earliest installation of
surface mechanical aerators as instream aerators was on the Great Miami River
in Ohio. Full scale instream aeration studies were conducted during 1965 on the
Upper Passaic River and during the late 1960's on the Delaware tidal basing.
Figure 4.7 shows a schematic of a mechanical surface aerator.
IV.
Compressed Air U-Tube Bubble Contactor.
A U-Tube aeration system is a gas
transfer process. The "U-Tube" designation is derived from the vertically-
oriented, geometric configuration of the water flow into which air or oxygen is
injected.
A deep shaft or hole is bored near the water body and is divided by either a flat
baffle or a concentric tubular baffle. The shaft and baffle are extended a few feet
above the surface of the water body. The baffle ends a few feet above the
bottom of the shaft. Aerated or oxygenated water is forced down one side of the
flat baffle or inside the tubular one.
The downward water velocity is designed to exceed the buoyant velocity of the
air or oxygen bubbles that are released into the water column. Consequently,
the bubbles are transferred downward and around the end of the baffle at the
bottom, thus, the name U-Tube. This process temporarily pressurizes the
4-15
MOTOR
WATER GUIDE PANEL
WATER INLET PIPE ?
FINAL 01/12/07
bubbles via the large increase in hydrostatic head with the U-Tube. This
increases the saturation concentration which, in turn, increases the DO deficit
thereby creating a greater driving force for the adsorption of oxygen into the
water column. At sea level, a 34-foot head of water creates approximately two
atmospheres of pressure inside a gas bubble (one due to the air pressure and
one due to the water pressure).
Figure 4.8 shows a schematic of a flat-baffled U-Tube being fed low-pressure
compressed air.
Typically, U-tubes can produce OTE's as high as 90 percent.
Figure 4.7 – Mechanical Surface Aerator
LOW PRESSURE AIR\
pically
40-100 feet
FINAL 01/12/07
Inlet Water
Figure 4.8 — Schematic
of Compressed Air U-Tube Contactor
FINAL 01/12/07
V
Vaporized High Purity Oxygen
(HPO). The use of pure oxygen injection into a
water body in lieu of atmospheric oxygen has been heavily promoted for over 35
years. Most installations used "trucked-in" liquid oxygen stored in pressurized
cylinders. However, a few installations have been designed to generate pure
oxygen on site.
Most applications are for deep water bodies such as lakes, reservoirs, and deep
running rivers such as those found below high head hydropower dams. Some
success has been achieved by creating artificially deep injection points by
injecting the pure oxygen into excavated deep vertical shafts. The basic units
inclusive in all designs are a liquid oxygen storage tank, an air-to-air vaporizer, a
pressure control system, a bank-side contactor for open water applications, or a
side-stream contactor for injection back into the waterway.
The OTEs of HPO systems are highly variable but can be as high as 90 percent.
A.
Pressurized Water Injection With Diffusers.
This system mixes
oxygen and water in a pressurized contactor tank. A stream of water is
pumped from the water body for use in the contactor. The oxygenated
water is then returned to the water body where it is distributed. Several
proprietary systems are available, of which the Speece Cone system
marketed by ECO2
is typical.
A conical contactor can be used to mix pressurized water with atomized
pure oxygen. These units are typically found in deep lakes, estuaries,
and sidestreams on large rivers below hydropower dams. Figure 4.9
shows a schematic of a conical pressurized water HPO contactor. This
super oxygenation technology reportedly can produce supersaturated DO
concentrations from 50 to 100 mg/L in water when mixed with pure
oxygen in the gas-water cone contactor.
CONE DIFFUSER
OXYGEN TANK
WATERWAY OR FORCE MAIN
FINAL 01/12/07
OXYGEN VAPORIZER
Figure 4.9 — Schematic of Pressurized HPO Contactor
FINAL 01/12/07
B.
U-Tube Bubble Contactor.
The concept of a U-Tube bubble contactor was
previously discussed. While these installations can operate using either
compressed air or pure oxygen, many are designed to use pure oxygen "trucked"
to the site.
Successful U-Tube oxygenators have been established on *deep rivers like the
35-foot deep reach of the Tombigbee River in Alabama. A 175-foot deep bore
hole was needed. It produces a 50 mg/I DO concentration at the injection point.
The relatively deep river prevented an immediate loss of oxygen to the
atmosphere. However, shallow streams and rivers may not be capable of
absorbing the oxygen before it comes into contact with air and becomes lost as a
gas into the atmosphere.
C.
Mobile (Barge-Mounted) Dispersion.
During the early 1970s researchers
at Rutgers University conducted experiments oxygenating the Passaic River
estuary with pure oxygen. The oxygen tank and diffusers were mounted on a
barge that would transverse the low-DO water in the estuary and disperse the
oxygen via the diffusers which were submerged along side the barge.
In 2004, the Liverpool England Harbor authorities deployed a mobile oxygenation
barge specifically designed and constructed to treat the harbor for low DO
problems (Figure 4.10). A fine bubble diffuser distributes the super oxygenated
water at depths from 3 to 25 feet. This system can achieve OTEs as high as
90%.
Figure 4.10– Barge Mounted HPO Diffuser System
4-20
FINAL 01/12/07
VI.?
Screw Pump Aeration. The screw pumps for the existing SEPA stations exhibit
significant aeration capabilities. The Oxygen Transfer Rate (OTR) of screw
pumps is expressed as pounds of oxygen transferred to the liquid per unit
horsepower-hour of the drive motor. The average OTR for Stations 3, 4, and 5
screw pumps were found by the MWRDGC to be 0.91, 0.97 and 0.91 lbs
02/hp/hr,respectively.
Conceivably, a side stream aeration station could be
specifically designed using only screw pumps for providing aeration.
EVALUATION
Advantages and Disadvantages of Technologies
In order to simplify the discussions of the advantages and disadvantages of the long
listed alternatives, these technologies will be grouped into the following categories:
1)
Air Diffusion Systems
2)
Head Loss Structures
3)
Mechanical Aerators
4)
U-Tube Aerators
5)
High Purity Oxygen Systems
6)
Screw Pumps
Below is a discussion of the advantages and disadvantages of these six categories.
Air Diffuser Systems
The use of compressed air diffusion systems is a proven method for supplemental
aeration of waterways. Although there have been operational issues associated with the
Devon and Webster in-stream aeration stations, these compressed air diffusion systems
have been in operation for over 25 years and are a fairly reliable method for providing
aeration of the NBCR.
Jet aerators have not been applied to waterway aeration but this method of air diffusion
has been proven to be reliable and effective in wastewater treatment aeration tanks. Jet
aerators offer the advantage of good mixing and the elimination of dead zones. Jet
aerators are much less likely to clog compared to fine bubble diffusers.
Table 4.1 contains a summary of the advantages and disadvantages of air diffusion
systems.
4-21
FINAL 01/12/07
TABLE 4.1
AIR DIFFUSION SYSTEMS – ADVANTAGES
&
DISADVANTAGES
Advantages
Disadvantages
Proven and well known
Diffuser area will tend to collect waterway
debris
No significant waterway traffic obstruction
Diffusers
?
can
?
clog
?
due
?
to
?
sediment
accumulation
Blowers and pumps are simple to operate
and maintain
Periodic?
replacement?
of?
diffusers?
is
required
With appropriate design, can meet variable
oxygen demands
Requires significant shore area for blowers
or pumps
Widely available from many manufacturers
May not be applicable to areas where
periodic dredging is required.
.
Can
?
be?
purchased
?
based
?
upon
performance specification
Jet aerator may aid mixing and eliminate
dead zones
Little operating experience for jet aerators
for supplemental aeration
Head Loss Structures
Head loss structures offer a simple way of adding oxygen to waterways. The existing
SEPA stations are an example of head loss structures which have been in operation for
many years providing a reliable method of waterway aeration.
The MWRDGC SEPA stations do have operational issues. These include aquatic weed
growth and excessive sediment deposits in the. pools. Since these structures need to be
placed on-shore to prevent waterway traffic obstruction, the shore space required is
quite high especially compared to compressed air diffusion systems.
Table 4.2 contains a summary of the advantages and disadvantages of head loss
structures.
TABLE 4.2
HEAD LOSS STRUCTURES – ADVANTAGES
&
DISADVANTAGES
Advantages
Disadvantages
Except for pumping to side stream sites,
no mechanical or electrical equipment is
operated or maintained.
Pumping to a side stream site is required
to avoid waterway traffic obstruction
Hydraulic
?
structures?
are?
generally
aesthetically pleasing
Side stream sites can only treat a fraction
of the total stream flow
Proven
?
design
?
parameters
?
for free-fall
sharp-crested weirs have been developed
Aquatic
?
weed
?
growth
?
and
?
sediment
deposits require periodic maintenance of
side stream pool
Low lift screw pumps provide beneficial
additional aeration
FINAL 01/12/07
Mechanical Surface Aerators
Mechanical surface aerators have been successfully used to provide supplemental
aeration to waterways. These units are simple and rugged with low maintenance
requirements.
However, they have high power demand compared to compressed air diffusion systems,
which explains why mechanical aeration systems used in wastewater treatment have
been replaced by compressed air fine bubble aeration systems. Also, the units are not
attractive and they cause nuisance noise.
Table 4.3 contains a summary of advantages and disadvantages of mechanical surface
aerators.
TABLE 4.3
MECHANICAL SURFACE AERATORS – ADVANTAGES
&
DISADVANTAGES
Advantages
Disadvantages
?
.
Simple to operate
Presents waterway traffic obstruction;
this can be mitigated
Rugged systems with low maintenance
Are not aesthetically pleasing
Widely?
available?
from?
a?
number?
of
manufacturers
Vulnerable to damage from high wind, cold
weather and high stream flows
Proven technology
High sound level
Can
?
be?
purchased?based
,
?
upon
performance specification
High power demand
U-Tube Aerators
U-Tubes have a high oxygen transfer efficiency and can provide a wide range of
aeration quantities. But they have high capital costs and access for maintenance is
difficult.
Table 4.4 summarizes the advantages and disadvantages of U-Tube aeration systems.
TABLE 4.4
COMPRESSED AIR U-TUBE CONTACTORS –ADVANTAGES & DISADVANTAGES
Advantages
Disadvantages
High oxygen transfer efficiency
Can
?
provide
?
wide?
range
?
of?
aeration
quantities
Access for maintenance is difficult since
the tubes are usually placed underground
High Purity Oxygen Systems
The use of high purity oxygen (HPO) in conjunction with various diffusion systems has
been highly promoted over the past 30 years, and its application has increased
significantly over the last decade. The fact that dissolved oxygen concentrations in
water can be significantly increased under pressurized conditions is not disputable,
however, what is questionable is how much of this supersaturated gas remains in
solution and remains usable upon exposure to normal atmospheric pressure. The HPO
4-23
FINAL 01/12/07
supplemental aeration systems, historically, have been applied only to deep bodies of
water such as reservoirs and deep rivers such as those which commonly prevail below
high-head power dams and flood control structures. Release to water depths of 60 feet
or more, with little turnover or mixing, provides the time for the DO to disperse and mix
before reaching the surface of a water body. Shallow rivers and streams may not
provide the detention time needed for the dispersion of the DO in the water body before
being lost to the atmosphere upon exposure at the water surface. Efficient dispersion of
supersaturated water in a low D.O. stream is dependent upon the design of the diffuser
system which delivers the supersaturated water stream.
Table 4.5 contains a summary of the advantages and disadvantages of High Purity
Oxygen systems.
TABLE 4.5
HIGH PURITY OXYGEN – ADVANTAGES & DISADVANTAGES
Advantages
Disadvantages
Excellent oxygen transfer efficiency
Dependent on future price for pure oxygen
Small on-shore space requirements
Increased truck traffic
Small space required for trucked in-
oxygen
More
?
space
?
required
?
for
?
site
generated oxygen
Complicated
?
oxygen
?
delivery/generation
system
Can be operated to meet varying oxygen
On-site storage of a potentially hazardous
demands
material
Complicated operation and maintenance
May not be efficient for shallow waterways
Screw Pumps
As stated previously, screw pumps have OTR's of about 0.9 lbs 0
2/hp/hr. This is a rather
low OTR compared to fine bubble systems with OTR of 1.97 – 3.2 lbs 02/hp/hr
("Wastewater Treatment Plants, Planning Design and Operation" by S. Quasim) or even
mechanical surface aeration with OTE's of 1.0 to 2.0 lbs 0
2/hp/hr.
Thus, screw pumps by
themselves are low efficiency aerators and their use would not be justified unless they
would be useful for operation in conjunction with other aeration devices. For example,
screw pumps are used in conjunction with free fall weirs at the MWRDGC SEPA
stations.
Therefore, screw pumps were eliminated as a long list supplemental aeration
technology. However, they will be carried forward as a low IA pumping method for head
loss structures.
Scoring of Qualitative Economic and Non-economic Criteria Matrix
The final long list of possible supplemental aeration technologies is as follows:
IA Fine Bubble Porous Ceramic Diffusers
IB Membrane Diffusers
IC Jet Aerators
4-24
FINAL 01/12/07
I IA Free-Fall Step Weirs with Screw Pumps
I IB Cascades with Screw Pumps
III Mechanical Surface Aerators
IV. Compressed Air U-Tubes
VA Pressurized Oxygen Contactor
VB.U-Tube Oxygen Contractor
VC Barge Mounted Diffusers
These long list alternatives were evaluated using the following criteria and weighting
factors. These criteria and weighting factors were a consensus decision between CTE
and MWRDGC and can be found in Technical Memorandum-3 (TM-3).
Criteria
Weighting Factor
Life Cycle Costs
50
Maintainability
5
Operability
10
Reliability
15
Energy Efficiency
5
Impacts Upon Neighbors
10
Expandability
5
Total
100
Each alternative was scored for each of the above criteria according to the following
scale:
Good – 3
Average – 2
Poor – 1
Each alternative was then evaluated relative to the weighting factor for each criteria. For
each criteria, the score for each alternative is multiplied by the criteria's weight to arrive
at a total score for that criteria. For example, if an alternative receives a score of 3 for a
criteria with a weight of 10, the total score for that criteria is 3x10 = 30.
In other technical memorandums, only whole numbers were given as scores for
alternatives. However, CTE technical
,
experts found that it was necessary to give
fractional scores to some alternatives. This was due to the relatively small differences
between some of the supplemental aeration technologies.
Table 4.6 contains the scoring for each alternative for the evaluation matrix. Below is an
explanation of the scoring shown in Table 4.6.
Life Cycle Costs
Life cycle costs were based upon the general knowledge of the costs associated with the
systems and not based upon a specific cost estimate.
4-25
FINAL 01/12/07
High purity oxygen systems are mechanically complex and the cost to purchase or
generate (on-site) the oxygen is high. Therefore all HPO systems were given a score of
1.0.
Mechanical surface aerators are high users of electrical power compared to other
aeration systems. Given the rising cost of electricity, this technology was given a score
of 1.0.
Cascades are poor aerators requiring high capital costs for a large pump station and a
large cascade. This technology was given a score of 1.0..
Free fall step weirs with screw pumps (SEPA concept) have better oxygen transfer
efficiency than cascades but require substantial land area and large structures and
pump stations. This was given a score of 1.5.
Jet aerators normally require a large blower station compared to fine bubble ceramic
diffusers since they have a lower oxygen transfer efficiency. Jet aerators also require a
substantial pump station. This technology
was
given a score of 2.0.
Membrane and ceramic diffusers have a high oxygen transfer efficiency and thus require
a relatively small blower station and do not require a pump station. However, membrane
facilities have a higher capital cost than ceramic diffusers. Thus, membrane diffusers
were given score of 2.0 and ceramic diffusers were given a score of 2.5.
Compressed Air U-Tubes have an excellent oxygen transfer efficiency and due to the
high dissolved oxygen achieved, require a small pump station. This technology was
given a score of 2.5.
FINAL 01/12/07
TABLE 4.6
EVALUATION MATRIX
Alternative
Life Cycle
Cost
Maintainability
Operability
Reliability
Energy
Efficiency
Impacts on
Neighbors
Expandability
Total Score
I. Air Diffusion
I.A. Fine
Bubble
Ceramic
Diffusers
Rank
2.5
2
3
2
2.5
3
3
xXXXxX
x
x
Weight
50
5
10
15
5
10
5
Score
125
10
30
30
12.5
30
15
252.5
I.
B
Membrane
Diffusers
Rank
2
2.0
2.5
1
2.5
3
3
xXX
XxX
x
x
Weight
50
5
10
15
5
10
5
Score
100
10
25
15
12.5
30
15
207.5
I.C. Jet
Aerators
Rank
2
2
3
1.5
1.5
3
3
xXX
XXX
X
x
Weight
50
5
10
15
5
10
5
Score
100
10
30
22.5
7.5
30
15
215
II. Head Loss Structures
II.A. Free
Fall Step
Weirs with
Screw
Pumps
Rank
1.5
- X
50 —
2.5
--X —3
X --
3
2.0
3
x
10
______________
1.5
_______
x
____. __
5
x
a _
—
Weight—
x
------15— — —
X
5
—
— ---To
5
Score
75
12.5
30
45
10
30
7.5
210
II.B.
Cascades
with Screw
Pumps
Rank
1.0
2.5
3
1
1
3
1.5
xXXXxx
x
x
Weight
50
5
10
15
5
10
5
Score
50
12.5
30
15
5
30
7.5
150
4-27
FINAL 01/12/07
TABLE 4.6 -EVALUATION MATRIX
III. Mechanical Surface Aerators
III.
Mechanical
Surface
Aerators
Rank
1.5
2
2
2
1
1
3
xXXXxx
x
x
Weight
50
5
10
15
5
10
5
Score
75
10
20
30
5
10
15
165
IV. Compressed Air U-Tube Contactors
IV.A.
Compressed
Air U-Tube
Contactors
Rank
2.5
2.5
3
1.5
2.5
3
2.5
xXXXxx
X
x
Weight
50
5
10
15
5
10
5
Score
125
12.5
30
22.5
12.5
30
12.5
245.0
V. High Purity Oxygen
?
•
V
Pressurized
Contactor
Rank
1
1.5
.?
1.5
2.0
1
2
3
xXXXxx
x
x
Weight
50
5
10
15
5
10
5
Score
50
7.5
15
30
5
20
15
142.5
V. U-Tube
Contactor
Rank
—x--
1
—
X --
1.5
1.5
--X—
-
2
___________________x
1
2
x
_______________
2.5
X
________.
X —
x
Weight
50
5
10
1-5
15
30
5
5
20
10
Score
50
7.5
12.5
5
140
V Barge-
Mounted
Diffusers
Rank1
1
1
2
1
1
3
xXXXxx
x
X
Weight
50
5
10
15
5
10
5
Score
50
5
10
30
10
.?
10
•?
15
130
3 = Good
2 = Average
1 = Poor
4-28
FINAL 01/12/07
Maintainability
HPO systems were given the lowest scores (1.0 to 1.5) because of their mechanical
complexity. Barge mounted HPO diffusion was given the lowest score (1.0) of the HPO
alternatives because of the need to also maintain the barge transportation system.
Fine bubble ceramic diffusers are a proven technology but based upon the MWRDGC
experience at the Devon and Webster stations for supplemental aeration, this
technology was given a score of 2.0.
Membrane diffusers should have similar maintenance issues as fine bubble diffusers
and were given a score of 2.0.
Mechanical aerators are simple to maintain but maintenance in a waterway will be
difficult and these devices were given a score of 2.0.
Although compressed air U-Tube facilities are relatively small due to a high oxygen
transfer efficiency, pumps and blowers must be maintained and this technology was
given a score of 2.0.
Although the existing SEPA stations have had maintenance issues, maintenance has
not been excessive and a score of
2.5
was assigned to this technology.
Lastly, jet aerators were given a score of 2.5 since there are no diffusers to replace or
maintain.
Operability
HPO systems are complex to operate and were given the lowest scores. Barge
mounted diffusion requires significant navigation skills and was given a score of 1.0 and
the other two HPO systems were given a score of 1.5.
Mechanical aeration systems can only be turned off or on as needed to meet DO
conditions. As such, they present operational challenges and were given a score of 2.0.
Membrane diffusers were given a score of 2.5 because of their short operating history
and no known use for waterway aeration.
Fine bubble ceramic diffusers, jet aerators, free fall weirs, U-tubes and cascades were
all given a score of 3.0. These devices are relatively simple to operate and offer the
operator significant control.
Reliability
Cascades and membrane diffusers were given the lowest score of 1.0. Cascades are
poor aerators and their ability to reliably produce the desired waterway DO level is
questionable. There is no known use of membranes for waterway aeration, thus
reliability for this application is unknown.
HPO systems can be reliably operated to meet a variety of waterway DO levels, thus
these systems were given a score of 2.0.
4-29
FINAL 01/12/07
Fine bubble ceramic diffuser systems have proven reliability for wastewater applications
but the MWRDGC experience at the Devon and Webster aeration stations indicates that
a score of 2.0 should be applied to this technology.
Step weirs have been used by the MWRDGC to reliably provide supplemental aeration
of waterways and were given a score of 3.0.
U-tubes and jet aeration do not have a significant operating history for supplemental
aeration and were given a score of 1.5.
Energy Efficiency
Mechanical aerators, cascades and the three HPO options were all given a score of 1.0.
Mechanical aerators have a very high energy demand to transfer oxygen. Cascades
produce poor aeration in relation to the pumping energy required. The HPO systems
utilize high head pumping and significant energy is required to generate the HPO
whether it is purchased or produced on-site.
Jet aerators have high energy demands for pumping and blowers and were given a
score of 1.5.
Compressed air U-Tubes, and fine bubble ceramic and membrane diffusers require
relatively low electrical energy and were given a score of 2.5.
Free fall step weirs using screw pumps are relatively energy intensive since screw
pumps are not energy efficient. Thus this technology was given a score of 2.0.
Impacts on Neighbors
Mechanical aerators and barge mounted HPO diffusers were given the lowest score of
1.0. Mechanical aerators are noisy, produce a visible water spray, and represent a
hindrance to boat traffic. A barge mounted aerator can hinder boat traffic, is highly visible
and will not be aesthetically pleasing.
A HPO contactor will require the use of HPO which would be generated on-site or
transported to the site. The operation of a HPO generation plant or transportation of
HPO to the site would be objectionable to nearby residences. These systems were
given a score of 2.0.
All other aeration systems were given a score 3.0 due to their minimal impacts on
neighbors.
Expandability
Free fall step weir facilities and cascades require considerable land space and
significant site preparation. Thus these facilities were given a score of 1.5.
Compressed air U-Tubes and HPO U-Tubes were given a score of 2.5 because of the
deep excavation required for this technology. All other technologies were given a score
of 3.0 because of ease of expansion.
4-30
FINAL 01/12/07
Short List of Technologies
Based upon the evaluation matrix discussed previously, the following four technologies
received the highest total scores:
Technology
Total Score
Ceramic Fine Bubble Diffusers
252.5
Compressed Air U-Tube
245.0
Jet Aerators
215.0
Free Fall Step Weirs
210.0
Thus these four technologies constitute the short list of supplemental aeration
technologies.
It should be noted that this short list includes two supplemental aeration technologies
which have a relatively long operating experience for the MWRDGC (namely Ceramic
Fine Bubble Diffusers and SEPA Stations) and two technologies which have relatively
little past operating experience for use in supplemental aeration (U tubesand Jet
Aerators). Since the main objective of this study was to determine the relative costs for
supplemental aeration and not to select a single technology for possible implementation,
no attempt will be made to recommend one of these technologies. Instead, a detailed
cost estimate for each of the four technologies will be conducted. Selection of a
technology for possible application to the SBCR and NBCR should be done after an
extensive review of the operating history of units currently being used for supplemental
aeration elsewhere. In addition, it would be worthwhile based upon the expenditures for
supplemental aeration to conduct pilot or lab studies of some or all of the short listed
technologies before making a final selection and beginning final design.
Since the passage of boat traffic is an important aspect of any supplemental aeration
system, this issue should be carefully considered as part of the recommended pilot or
lab studies. Also, boat traffic passage should be carefully considered when reviewing
the operating history of a supplemental aeration technology.
Land Availability for Supplemental Aeration
Figures 4.11 through 4.14 contain conceptual layouts for the 80 g/s (oxygen)
(15,200/lbs/day of oxygen) aeration stations for all four short-listed technologies. This
layout for the largest station was prepared so that the maximum space requirements for
the four technologies could be determined. The SEPA technology requires the most
area with a space requirement of about 1 acre for the 80 g/s (15,200 lbs/day) station. A
30 g/s SEPA station would require about 1/2 acre.
Using the space requirements for the SEPA station as the maximum space requirement,
aerial photographs were examined to determine if sufficient vacant land was available at
each of the four supplemental aeration sites. Appendix D contains four figures which
show each of the four aeration station locations with an overlay showing the land
requirements for the SEPA technology. The Diversey site was not large enough for a 1
acre footprint. However, it is large enough for a 1/2 acre footprint, which is the size
required at this location. The overlay on the Diversey figure in Appendix D shows a 1/2
acre overlay. Each site has the available vacant land space available for the SEPA
4-31
FINAL 01/12/07
technology. Thus, any of the sites could be used for any of the four short-listed
technologies without the need for building demolition.
The cost estimates assume that the land needed for the supplemental aeration stations
would have to be purchased at a cost of $1.2 million per acre. This land cost is probably
conservative since the MWRDGC Engineering Department estimated the highest land
cost for property along the NBCR and SBCR to be $675,000 per acre. For simplicity,
the SEPA station land requirements were used to obtain land costs for each of the four
technologies. That is, one acre was assumed to be needed for a 80 g/s (oxygen) station
and 1/2 acre was needed for 30 g/s (oxygen) station.
FINAL 01/12/07
250'
FENCE
80'
FLOW.
"44 30' --lb.
WET WELL
••
?
•?
•?
• ••
?
•?
•?
•?
•?
•?
•
?
RIVER
?
•
• .?
\\-e?
SLUICEGATES
Figure 4.11 — 80 g/s (Oxygen) SEPA Station Conceptual Layout
60'
STEP
WEIRS
PUMP• STATION
100'
4-33
FINAL 01/12/07
The jet aeration system requires a building which would contain 19 pumps and 15
blowers. This arrangement is typically used for the KLA Systems Inc. (Assonet, MA).jet
aeration process used for cost estimation purposes for this report. This process uses
individual manifolds each with 32 jets. For the 80 g/s of oxygen aeration station, a total
of 19 manifolds are required. In the typical KLA system design, each manifold uses a
single pump and thus 19 separate pumps are required. To supply air to the 19
manifolds, the KLA system design includes 15 blowers (2 standby). The use of this
large number of blowers allows flexibility in supply and controlling air to the jet aeration
manifolds. If a design of a jet aeration system is contemplated in the future, in all
probability a smaller number of pumps and blowers would be selected. However for
conceptual cost estimation purposes, this initial design of the jet aeration system is
sufficient.
150'
FENCE
PUMP AND BLOWER BUILDING
43
ti
ro
AIR PIPING
TO JETS
PUMPED WATER
DISCHARGE TO
JETS
PUMPED
WATER
SUPPLY
. •?
.?
•
?
• • •
?
• • • •
?
• •
RiVER.....
?
•? •?
.? •? •? •
FINAL 01/12/07
200'
Figure 4.12 - 80 g/s (Oxygen) Jet Aeration Station Conceptual Layout
4-35
FINAL 01/12/07
40'
BLOWER
2
BUILDING
AIR
PIPING
FENCE
.?
.
?RIVER
•?
,?
.....
?
.?
..
?
TO
.
DIFFUSERS
?
Figure 4.13 — 80 g/s (Oxygen) Ceramic Fine Bubble Diffuser Station Conceptual Layout
4-36
OO
F'UNIPED
WATER
SUPPLY
X BLOWER BUILDING
ELECTRICAL
BUILDING
U-TUBE CONTACTOR
X?
BUILDING
?
DISCHARGE
-041
DIFFUSER
• FIFE
?
II?
A
25'
FINAL 01/12/07
100'
FENCE
...?
•?
.
?
• •
RIVER.
•?
•?
?
......?
INTAnm
"
•
Figure 4.14 – 80 g/s (Oxygen) Compressed Air U-Tube Station Conceptual Layout
4-37
FINAL 01/12/07
Cost of Supplemental Aeration Stations
Appendix A contains the various unit costs utilized to determine the Capital and
Operating costs for the four supplemental aeration stations. The unit costs were derived
either from TM-3 and/or TM-1WQ.
Appendix B contains the detailed spreadsheets that were used to estimate the capital
costs for the 30 g/s (oxygen) supplemental aeration stations. Appendix C contains the
detailed spreadsheets that were used to estimate the operating and maintenance costs
for the 30 g/s supplemental aeration stations. Cost estimates for the 80 g/s aeration
stations were extrapolated based upon the costs for the 30 g/s (oxygen) stations.
Capital and operating costs were estimated for each of the short-listed supplemental
aeration technologies which were:
1.
U-Tubes
2.
SEPA Stations
3.
Ceramic Diffusers
4.
Jet Aeration
The scope of this conceptual level study precluded an analysis of the application of the
four short listed technologies to the various supplemental aeration sites. It may well be
that site conditions will dictate the choice of a supplemental aeration technology. Also it
may be necessary to conduct full-scale and/or pilot plant studies to determine the design
criteria for supplemental aeration stations. For example, the MWRDGC conducted pilot-
plant tests of the SEPA concept and the information from these tests were used to
design the existing five SEPA stations on the Cal-Sag Channel.
Table 4.7 contains a summary of the capital and annual maintenance and operation
costs for the four short-listed technologies. These are the total costs for implementing
these technologies at the four locations and aeration capacities determined by the
Marquette Modeling runs.
U-tubes and ceramic diffusers represent the lowest present worth. However, these cost
estimates are planning level and are based upon general design factors which may not
be applicable to the site-specific conditions on the SBCR and NBCR. As stated
previously, it would be prudent to select a supplemental aeration technology based upon
a review of the operating history of the existing MWRDGC supplemental aeration
facilities and other similar facilities elsewhere. Also the design criteria for the
supplemental aeration stations should be verified by pilot and/or laboratory studies.
Lastly, a rigorous use of the Marquette Model should be undertaken complete with a
sensitivity analysis to determine the final sizing and locations of the supplemental
aeration stations. If necessary the model may be refined to ensure that this sizing and
location represents the best simulation for the NBCR and SBCR.
FINAL 01/12/07
TABLE 4.7
SUMMARY'OF CAPITAL AND ANNUAL COSTS
Cost of Four Supplemental Aeration Stations on NBCR and SBCR
Total Capital
Annual O&M
Total Present
Worth
U-Tubes
$36,282,000
$554,000
$47,362,000
SEPA
$89,939,000
$2,141,000
$132,759,000
Ceramic Diffusers
$35,518,000
$1,070,000
$56,918,000
Jet Aeration
$54,145,000
$2,594,000
$106,025,000
As can be seen in Table 4.7, the range of costs for supplemental aeration for the NBCR
and SBCR are as follows:
Capital Costs
$35.5 Million – $89.9 Million
Annual Operation and Maintenance Costs
$554,000 – $2.6 Million
Total Present Worth
$47.4 Million – $132.6 Million
SUMMARY AND CONCLUSIONS
A planning level study was conducted to determine the potential technologies and costs
for adding supplemental aeration to the NBCR and SBCR. The supplemental aeration
provided would be in addition to the aeration provided currently at the Devon and
Webster Avenue diffused aeration stations. To determine the size and location of the
additional aeration stations, a water quality simulation model developed by Marquette
University for the MWRDGC was used. Since the IEPA has not reached a decision on
the DO target levels for the NBCR and SBCR, a target DO of a minimum of 5 mg/I to be
achieved 90% of time was selected.
After a review of a long list of technologies using an evaluation matrix which included
both non-economic and economic factors from four technologies were selected for a
detailed opinion of probable cost estimate.
The opinion of probable cost estimate was based upon constructing a total of 4
additional stations on the SBCR and NBCR. These 4 stations were found to be
necessary by Marquette Model runs to achieve the DO target levels 90% of the time for
the data base simulated in the Marquette Model (2001 and 2020). The total capital cost
ranged from $35.5MM to $89.9MM. The total annual operation and maintenance cost
ranged from $554K to $2.6 MM.
It should be noted that the main purpose of the study was to determine the magnitude of
the costs associated with supplemental aeration of the NBCR and SBCR and not to
select a technology for possible application. Thus, it would be necessary to conduct an
4-39
FINAL 01/12/07
in depth study of the operating experience of the four technologies for supplemental
aeration. This is especially true for jet aerators and U-tubes where there is little
operating experience. Also pilot and full-scale studies of some or all of the technologies
should be initiated to refine the cost estimates, help to select a technology for possible
implementation, and develop design criteria.
It should also be emphasized that a decision to implement supplemental aeration of the
NBCR and SBCR should only be reached after an integrated study of all IEPA requested
water quality management options has been undertaken. This study would determine
the relative costs and benefits of these options and then determine their priority for
potential implementation. Such an integrated study is beyond the scope of this
Technical Memorandum.
FINAL 01/12/07
APPENDIX A
Unit Costs Used in Cost Estimates
FINAL 01/12/07
UNIT COSTS USED IN COST ESTIMATES
Life cycle cost (LCC) analysis requires the development of certain constants that will be
used throughout the evaluation of alternatives. Values used for constants are presented
below. These values have been developed in consultation with MWRDGC staff and
represent actual values or agreed upon assumptions.
1.?
Present Worth Factors for Life-Cycle Costs
•
Years
?
20
•
Annual interest rate
?
3%
•
Annual inflation rate
?
3%
• Annuity Present Worth Factor (with inflation)
?
19.42
2.?
Design Life
•
Structural Facilities
?
20
• Mechanical Facilities?
20
3.
Electrical Cost
?
$0.075/kW-hr
4.
Labor Rates Per Hour Including Benefits (11
•
Electrician
?
$159.50/hr
• Operations?
$90.00/hr
• Maintenance
?
$90.00/hr
5. Parts and Supplies?
5 percent
6. Contractor Overhead and Profit (2)?
15%
7. Planning Level Contingency (3)?
30%
8.
Engineering Fees including Construction Management
(4)?
20%
(1) A multiplier of 2.9 was used to reflect benefits as provided by the
MWRDGC.
(2)
Percent of Total Construction Cost
(3) Percent of Total Construction Cost plus Contractor Overhead and
Profit
(4)
Percent of Total Construction Cost, Contractor Overhead and Profit
plus Contingency
FINAL 01/12/07
APPENDIX B
Detailed Capital Cost Estimates for Four Short-Listed Supplemental Aeration
Technologies
FINAL 01/12/07
APPENDIX C
Detailed Annual Cost Estimates for Four Short-Listed Supplemental Aeration
Technologies
FINAL 01/12/07
APPENDIX D
Figures Showing Land Availability for Four Supplemental Aeration Stations
North Branch
Chicago River
Proposed
Aeration
Station Site
W. Diversey
Avenue
Direction
Of Flow
FINAL 01/12/07
Figure D-1 – Land Availability for 30 g/s SEPA station at Diversey Avenue and the
North Branch Chicago River
Proposed
Aeration
Station Site
FINAL 01/12/07
Figure D-2 — Land Availability for 30 g/s SEPA station at Chicago Avenue and the
North Branch Chicago River
FINAL 01/12/07
Figure D-3 – Land Availability for 30 g/s SEPA Station at 18
th Street and the South
Branch Chicago River
South Branch
Chicago River
Proposed
Aeration
Station Site
Direction of
Flow
S. Halsted St.
FINAL 01/12/07
Figure D-4 —Land Availability for 80 g/s SEPA station at Halsted Street and the
South Branch Chicago River
FINAL 01/12/07
APPENDIX B
Detailed Capital Cost Estimates for Four Short-Listed Supplemental Aeration
Technologies
TABLE BA
CAPITAL COST ESTIMATION FOR U-TUBE SUPPLEMENTAL AERATION (30 g/s)
PROJECT NO. 40779
DIVISION
ITEM DESCRIPTION
UNITS
NO.
MATERIAL
i
LABOR
INSTALLED COST
UNIT COST
TOTAL COST
% MAT COST
UNIT COST
TOTAL COST
TOTAL
1
GENERAL REQUIREMENTS
$138,576
2
SITEWORN
Cut/Fill
CY
1450
$5.00
$7,252
$7,250
Removable Bollards
BA
12
$300.00
$3,600
$3,600
Fencing
LS
2
58,500.00
. $13,000
$13,000
MIscellaneOus Sltework
CY
100
$36.00
$3,600
$3,600
Miscellaneous Sitewotir
SF
3200
$5.00
$16,000
$16,000
3
CONCRETE
Slabs
CY
84
$500.00
342,000
$42,000
Wet Well
LS
1
$19,500.00
$19,500
$19,500
9
MASONRY
Split Block Masonry Building
SF
2000
$100.00
$200,000
$200,000
10
FINISHES
Coatings
LS
1
$20,000.00
$20,00
•
?
$20,000
•?
11
EQUIPMENT
Vertical turbine Pumps and Appurtenances
EA
8
$78,600.00
$612,000
$812,000
Blower
EA
3
$8,200.00
$24,800
40%
59,840
$34,440
Drill & Prep 12' die U-Tube Shaft
FT
115
$1,742.00
$200,330
$200,330
Casing Material (Welded Steel, 1')
LB
87300
$2.00
5174,600
5174,600
Install U-Tube Casing
FT
116
$100.00
$11,600
$11,500
Install Bottom Plug (Concrete and Mortar)
CY
25
$760.03
$18,750
$18,760
Pump Water from Shaft and Prepare Casing
LS
1
$52,500.00
$52,500
$52,500
Bubble Collector and Appurtenances
EA
1
$18,000.00
$16,000
$16,000
Diffusers
LS
1
$12,000.00
$12,000
$12,000
13
SPECIAL CONSTRUCTION
Pressure Gages/Transmitters
EA
2
$1,500.00
$3,000
$3,000
Row Meter (12' Mag)
EA
2
$13,500.00
' $27,000
$27,000
15
MECHANICAL
Alr
Supply Piping and Appurtenances
LF
260
$12.00
- $3,000
$3,000
Control Valve
EA
8
$3,000.00
$24,000
$24,000
20' Pump control Valve
EA
8
$28,000.00
$224,000
$224,000
Isolation Valves
EA
10
$14,000.00
$140,000
$140,000
20' DIP
LF
153
$180.00
$27,450
$27,450
30' DIP
LF
59
$270.00
$13,500
513,500
20' Flexible Piping
LF
300
$180.00
$54,000
$54,000
Inner Piping system
LF
150
$450.00
$87,500
$67,500
liDPE Diffuser Pipe
LF
4,000
$15.00
$60,000
$60,000
Pressure Regulating Station
EA
20
55,000.00
$100,000
$100,000
Diffuser Supports
EA
400
$150.00
$60000
$60,000
Lateral Installation (Within Water Column)
LF
4,000
$94.00
$376,000
$376,000
16
ELECTRICAL AND INSTRUMENTATION
Supply
LS
1
$76,000.00
,$75,000
$75,000
Control systems and Instrumentation
LS
1
$50,000.00
$50,000
$50,000
Control wiring
LS
1
$10,000.00
$10,000
$10,000
SUBTOTAL
$2,910,096
Contractor OH&P 0 15%
$436,514
Subtotal
93,346,610
Planning Level Contingency 0 30%
$1,003,983
Subtotal
$4,350,594
Misc. Capital Costs
Legal and Fiscal Fees 0 15%
$652,689
Engineering Fees Including CM 0 20%
$820,119
Subtotal
81,822,708
Project Total
$5,873,301
I
B-2
?
Suppl. Aeration COST9.x1sU-TUBE 30 gms per
see •
CAPITAL
TABLE B.2
CAPITAL COST ESTIMATION FOR JET AERATION (30 g/s)
PROJE
CT
DIVISION
ITEM DESCRIPTION
UNITS
NO.
MATERIAL?
LABOR'
INSTALLED COST
I UNIT COST
TOTAL COST?
% MAT COST
UNIT COST
TOTAL COST
TOTAL
1
GENERAL REQUIREMENTS
^
$212,953
Mobilization for dredging
LS
1.
$56,500.00
$56,500
$56,500
River Dredging
CY
8333
$20.00
$166,6671
Sheet
Coffer
PilingDam
SFSF
i?
15000
$30.00
$450,0001
$450,000
20000
!?
$52.50
$1,050,000
$1,050,000
Blower & Pump Bidg. Excavation
i?
CY
8167
$7.00
$57,167'
$,57,167
Back811
CY
5204
$8.00
$41,630
$41,630
10
Pump and Blower Building
FINISHES
SF
5000
'?
$100.00
$500,0'.:
$500,000
Coatings
LS
1
$20,000.00
$20,00•
$20,000
11
EQUIPMENT
Pumps, Blowers, Manifolds
LS
1
$950,000.00
$950,00.
40%
$380,00.
$1,330,000
13
SPECIAL CONSTRUCTION
Pressure Gages/Transmltters
EA
!?
1
$1,500.00
$1,5..
$1,500
15
1 MECHANICAL
i
Air Supply Piping and Appurtenances
LF
800
$12.00
$9,60 '
$9,600
Control Valve
EA
7
$3,000.00
$21,00.
$21,000
20' Pump control Valve
EA
7
$28,000.00
$196,00.
$196,000
Isolation Valves
EA
7
$14,000.00
$98,00.
$98,000
30' DIP
LF
50
$270.00
$13,500
$13,500
16
ELECTRICAL AND INSTRUMENTATION
1
I
Control systems and Instrumentation
SUBTOTAL
I
LS
i
,
$30,000.00
$30,000
40%
$12,000
$42,000
$4,472,016
Contractor OH&P ®16%
$670,802
i
Subtotal
Planning Level Contingency 0 30%
^
,
$5,142,819
$1,542,846
Subtotal
i
1
$6,685,6641
Misc. Capital Costs
I
Legal and Fiscal Fees @ 15%
Engineering Fees including CM ®20%
.
I
;
$1,002,850
Subtotal
i
$2,339,9821
I
I
B-3
?
Suppl. Aeration COST9.xlsJet Mr 30 gms per sec-CAPITAL
TABLE B.3
CAPITAL COST ESTIMATION FOR SEPA 30 g/s STATION
•
DIVISION
ITEM DESCRIPTION
NO.
MATERIAL
I?
LABOR
INSTALLED COST
UNIT COST
TOTAL COST
% MAT COST
UNIT COST
TOTAL COST
TOTAL
1
11
GENERAL REQUIREMENTS
EQUIPMENT
SEPA Station (I)
SUBTOTAL
Contractor
OH&P
0 15%
Subtotal
Planning Level Contingency 0 30%
Subtotal
Misc. Capital
Costs
Legal
and
Fiscal Fees @ 15%
Engineering
Fees
including CM 0 20%
Subtotal
Project Total
i
133333
$54.30
$7,239,715
I
$361,986
$7,239,715
$7,601,701
$1,140,255
$8,741,956
$2,622,587
$11,364,543
$1,704,681
$2,272,909
$3,977,590
$15,342,133
>
sts were obtained from existing SEPA station construction costs, updated to 2006 rates using ENR Index of 7660.
B-4
?
Suppi. Aeration COST9.xIsSEPA 30 gms per sec CAPITAL
TABLE B.4
CAPITAL COST ESTIMATION FOR CERAMIC DIFFUSER SYSTEM
(30 g/s)
DIVISION IITEM DESCRIPTION
UNITS
NO.
MATERIAL
LABOR
INSTALLED COST
UNIT COST
TOTAL COST
% MAT COST
UNIT COST
TOTAL COST
TOTAL
GENERAL REQUIREMENTS
•
$135,394
2
SITEWORK
3
CONCRETEBackfillBlower
Diversion
Sheet
Goiter
Mobilization
River DredgingPilingDemBldg.
Pumpingfor
Excavationdredging
DAYCYCYCYSFLSSF
20000150008333481667201
$56,500.00'
?
$3,600.00S52$0$30.00$20.00$8.00$7.00
$1,050,000$450,000$166,667$72,000$58,500$3,852$4,667
$1,050,000$166,6675450,000$72,000$56,500$3,852$4,687
9
MASONRY
Blower Building
SF
10
FINISHES
2600
$100.00
$250,000
$250,000
11
EQUIPMENTCoatings
LS
1
$20,000.00
$20,000
$20,000
13
SPECIAL
Blower
Local
PLCBlowerSpray
DiffusersInlet
PumpCONSTRUCTIONActuatorFilter
EALSEA
LS
LSLS
1
3
1111
510%000.00590,000.00525,000.00$15,000.00520,000.00$19,000.00
.?
5100,000$19,000$75,000$90,000$15,000$20,000
40%40%
$30,000$38,000
$100,000$105,000$128,000$19,000$15,000$20,000
15
MECHANICAL
16
ELECTRICAL
AC
HOPE
Air
Diffuser
Control
Supply
UnitDiffuser
ValveSupportsPkAng
AND
PipeINSTRUMENTATIONand
Appurtenances
EAEAEALFLF
1000100080
3
1
$5,000.00$3,00100$150.00$15.00
529.00
$15,000$12,000$29,000$5,000$9,000
40%40%40%40%40%
$11,600$2,000$4,800$3,60056,000
$21,000516,800$12,800$40,600$7,000
Control
SupplyControl
wiringsystems
and Instrumentation
LSLSLS
111
$40,000.00560,000.00$6,000.00
$60,000$40,000$8,000
40%40%
40%
$24,000$16,000$3,200
$11,200$56,000$84,000
SUBTOTAL
$2,843,279
SubtotalContractor
OH&P 0 15%
$3,269,771$428,492
SubtotalPlanning
Level Contingency 0 30%
$4,260,703$930,931
&Usu.
Capital Costs
SubtotalEngineering
Legal and Fiscal
Fees
Fees
Including
0 16%CM
0 20%
$1,487,746
$850,141$637,605
Project Total
$6,738,449
B-5
?
Suppi Aeration COST9AlsOlfruser 30 gms per sec-CAPITAL
8
ffi
‹
6
a
EL.
mU
W
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TABLE BA
CAPITAL COST ESTIMATION FOR JET AERATION (80
g/s)
DWISION
ITEM DESCRIPTION
UNITS
NO.
MATERIAL
LABOR
INSTALLED COST
UNIT COST
TOTAL COST
% MAT COST
UNIT COST
TOTAL COST
TOTAL
1
GENERAL REQUIREMENTS
$567,875
2
SITEWORK
Malt/Alton for dredging
LS
1
22929
River Dredging
CY
5150,666.67$20.00
$444,4445150,667
5444,444$150,667
Colter
Sheet
Diversion
DamPiingPumping
DAYSFSF
533334000053
$3,800.00$52.50$30.00
$2,800,000$1,200,000$192,000
$1,200,000$2,800,000$192,000
BacictliBlower
& Pump Bldg. Excavation
CYCY
2177813877
$8.00$7.00
$152,444$111,012
$152,444$111,012
r
3
CONCRETE
Wetwell
LS
1
$53,333.33
$53,333
$53,333
9
MASONRY
Pump and Blower Bulking
SF
13333
$100.00
$1,333,333
$1,333,333
10
FINISHES
Coatings
LS
1
$53,333.33
$53,333
$53,333
11
EQUIPMENT
Pumps, Blowers, Manifolds
LS
1
$2,533,333.33
$2,533,333
40%
$1,013,333
$3,546,667
13
SPECIAL CONSTRUCTION
Pressure Gages/Transmkters
EA
1
$4,000.00
$4,000
$4,000
Flow Meter
EA
1
$36,000.00
$38,000
$36,000
15
MECHANICAL
Air Supply Piping and Appurtenances
LF
2133
$12.00
$25,600
$25,600
Control Valve
EA
19
$3,000.00
$56,000
$56,000
20' Pump control Valve
EA
19
$28,000.00
$522,667
$522,867
Isolation Valves
EA
19
$14,000.00
$261,333
$261,333
20' DIP
LF
267
$180.00
$48,000
$48,000
30' DIP
LF
133
5270.00
$36,000
$36,000
Priming System
EA
1
$13,333.33
$13,333
$13,333
18
ELECTRICAL AND INSTRUMENTATION
Supply
LS
1
$133,399.33
$133,333
40%
$53,333
$188,687
Control systems and Instrumentation
LS
1
$80,000.00
$80,000
40%
$32,000
$112,000
Control wiring
LS
1
$13,333.33
313,333
40%
$5,333
518,667
SUBTOTAL
$11,925,376
Contractor CHAP 0 15%
51,768,606
Subtotal
$13,714,183
Planning Level Contingency
Et
30%
$4,114,255
Subtotal
$17,828,438
Misc. Capital Costs
Legal and Fiscal Fees 0 15%
$2,674,266
Engineering Fees Including CM 0 20%
$3,585,888
Subtotal
56,239,953
Project Total
$24,088,391
r-
B-7
?
11
TABLE B.7
CAPITAL COST ESTIMATION FOR SEPA 80 gfs STATION
PROJECT NO. 40779
DIVISION
ITEM DESCRIPTION
, UNITS
NO.
MATERIAL
LABOR
INSTALLED COST
UNIT COST
TOTAL COST
% MAT COST
UNIT COST
TOTAL COST
TOTAL
1
11
GENERAL REQUIREMENTS
EQUIPMENT
SEPA Station (I)
SUBTOTAL
Contractor OH&P @ 15%
Subtotal
Planning Level
Contingency 0 30%
Subtotal
Misc. Capital Costs
Legal and Fiscal Fees @ 15%
Engineering Fees Including CM @ 20%
Subtotal
Project Total
$/gpm
j
355555
______
I
$54.30 •?
$19,305,907
$965,295
$19,305,907
$20,271,203
$3,040,680
$23,311,883
$6,993,565
$30,305,448
$4,545,817
$6,061,090
I$10,606,907
$40,912,355
(1) Costs were obtained from existing SEPA station construction costs, updated to 2006 rates using ENR Index of 7660.
B-8
?
Suppl. Aeration COST9.xisSEPA 80 gps-CAPITAL
TABLE B.8
CAPITAL COST ESTIMATION FOR CERAMIC DIFFUSER SYSTEM (80 g/s)
PROJECT
DIVISION
ITEM DESCRIPTION
UNITS
I?
NO.
MATERIAL
LABOR
INSTALLED COST
UNR COST
TOTAL COST
%MAT COST
UNIT COST
TOTAL COST
TOTAL
1
GENERAL REQUIREMENTS
—
$361,051
2S
Sheet
River
MobilizationfordredgingDredgingPlling
CYSFLS
40000222221
$150,666.67$20.00$30.00
$1,200,000;$444,444]$160,6671
$1,200,000$444,444$150,667
Coffer Dam
SF
53339
$52.50
$2,800,000
$2,800,000
Diversion Pumping
DAY
3
CONCRETEBack
BlowerRldg.Excavafanill
CYCY
1284177853
$3,600.00$8.00$7.00
$192,000;$10,272$12,444;
$192,000$10,272$12,444
9
MASONRY
10
FINISHESBlower
Building
I
?
SF
.,
?
6667
I?
$100.00
$666,667'
$666,667
11
EQUIPMENT
I
I
Di fusers
LS.
1
I
01
Blower
E
.
DI
Local Inlet Filler
LS
1
I
?
$53,333.33
$53,33
1
Spray Pump
LS
1
l?
$40,000.00
1
$40,000
Blower Actuator
LS
1
$50,666.67
$50,667
$50,667
13
SPECIAL
PLC
CONSTRUCTION
EA
1
$266,666.67
1
15
MECHANICAL
1
Alr Supply Piping and Appurtenances
LF
2667
$29.00
40%
3
$108,267
Control Valve
EA
3
$8,000.00
$24,000
40%
$9,600
$33,600
HOPE D (fuser Plpe
LF
2667
$15.00
$16,000
$56,000
DfluserSuppons
EA
213
$150.00
0001
$32,000
$12,80
0
$44,800
16
AC Unit
ELECTRICAL AND INSTRUMENTATION
FA
1
I?
$13,333.39
3
$5,333
$18,667
Supply
LS
1
$160,000.00
$160,000
$64,000
$224,000
Control systems and Instrumentation
LS
1
$106,666.67
$106,667
ConVOI wiring
LS
1
§21,333.33
393
SUBTOTAL
1
i
$7,582,079
-
Contractor OH&P @ 15%
$1,137,312
Subtotal
$8,719,390
Planning Level Contingency @ 30%
I
I
$2,615,817
1
Subtotal
Misc. Capital Costs
Legal and Fiscal Fees @ 15%
I
I
$1,700,281
Engineering Fees Including CM @ 20%
1
$2,267,041
Subtotal
Project Total
,
I
$3,967,323
1
8-9
?
Suppl. Aeration COST9AsDiffuser 80 gps-CAPITAL
FINAL 01/12/07
APPENDIX C
Detailed Annual Cost Estimates for Four Short-Listed Supplemental Aeration
Technologies
TABLE 0.1
ANNUAL O&M COSTS FOR U-TUBE 30 gis AERATION SYSTEM
PRESENT WORTH FACTOR.
UFE,N
20
INTEREST, I
3
INFLATION,
3
PRESENT WORTH FACTOR
19.42
Energy Cost, $
Average
?
&DOM() SAWN
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
($/02Y)
ANNUAL
COST
($)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
OPERATIONS
ENERGY - ELECTRICAL
33.48
24
802.9
$60.22
$14,654
19.42
$284,575
SUBTOTAL
$14,654
.
$284,575
NO. OF
OPERATORS
(per
day)
TIME
(hrs/day/openator)
TOTAL TIME
(hrs./day)
LABOR
RATE
($/hr)
ANNUAL
COST
($)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
($)
MAINTENANCE
ROUTINE MAINTENANCE
Blowers '
1
0.12
0.12
$90.00
53,942
19.42
$76,554
Pumps
1
0.12
0.12
$90.00
$3,942
19.42
$76,554
LABOR-OPERATOR
Blowers & Pumps
1
0.24
0.24
$90.00
$5,256
19.42
$102,072
ELECTRICIAN
1
0.06
0.06
5159.50
53,493
19.42
$67,835
SUBTOTAL
$18,633
$323,014
CONSTRUCTION
COST OF NEW
EQUIP. & PIPING ($)
'X FOR ANNUAL
PARTS
AND
SUPPUES
NUMBER OF LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
PARTS
AND
SUPPLIES
PARTS AND SUPPUES
1,438,050
5%
971,903
19.42
$1,396,347
SUBTOTAL
$71,903
$1,396,347
TOTAL ANNUAL
O&M
?
$103,189
TOTAL PRESENT WORTH
0
&
M COST
?
$2,003,936
C-2
?
Suppl. Aeration COST9.r.IsU-Tube 30 gms per sec - O&M
ANNUAL
TABLE C.2
O&M COSTS FOR JET AERATION
30
g/s SYSTEM
PRESENT WORTH FACTOR
LIFE,N
20
INTEREST,
3
INFLATION, I
3
PRESENT WORTH FACTOR
19.42
Energy Cost, $
Average
?
$0.0750 $/kWh
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
($/daY)
ANNUAL
COST
($)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
($)
OPERATIONS
ENERGY - ELECTRICAL
862.5
24
20700.0
$1,552.50
$377,775
19.42
$7,336,391
SUBTOTAL
$377,776
$7,336,391
NO. OF
OPERATORS
(per day)
TIME
(hrs/day/operator)
TOTAL TIME
(hrs/day)
LABOR
RATE
($/hr)
ANNUAL
COST
($)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
($)
MAINTENANCE
ROUTINE MAINTENANCE
Pumps
2
0.1
0.2
$90.00
$6,570
19.42
$127,589
Blowers
2
0.1
0.2
$90.00
$6,570
19.42
$127,589
LABOR-OPERATOR
Blowers & Pumps
2
0.1
0.2
$90.00
$4,380
19.42
$85,060
ELECTRICIAN
1
0.05
0.05
$159.50
$2,911
19.42
$56,529
SUBTOTAL
$20,431
$396,768
CONSTRUCTION
COST OF NEW
EQUIP. & PIPING (5)
% FOR ANNUAL
PARTS
AND SUPPLIES
NUMBER OF LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
($)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
($)
PARTS AND SUPPLIES
PARTS AND SUPPLIES
1,311,100
5%
$65,555
19.42
$1,273,078
SUBTOTAL
$65,555
$1,273,078
TOTAL ANNUAL O&M
?
$463,761
TOTAL PRESENT WORTH 0 & M COST
?
$9,006,236
C-3
?
Suppl. Aeration COST9.xlsJet Aer 30 gms per sec-O&M
TABLE C.3
ANNUAL O&M COSTS FOR 30 g/s SEPA STATION
PRESENT WORTH FACTOR
LIFE,N
20
INTEREST, I
3
INFLATION, J
3
PRESENT WORTH FACTOR
19.42
Energy Cost, $
Average
?
$0.0750 $/kWh
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
($klaY)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
OPERATIONS
ENERGY-
ELECTRICAL
745.6
24
17894.4
•
$1,342.08
$326,573
19.42
$6,342,044
SUBTOTAL
$326,673
$6,342,044
NO. OF
OPERATORS
(per day)
TIME
(has/day/operator)
TOTAL TIME
(hrs/day)
LABOR
RATE
($/hr)
ANNUAL
COST
($)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
MAINTENANCE
ROUTINE MAINTENANCE
Cut & Landscape
2
0.4
0.8
$90.00
$17,520
19.42
$340,238
Pump Maintenance
1
0.1
0.1
$90.00
$3,285
19.42
$63,795
LABOR - OPERATOR
1
2
2
$90.00
$43,800
19.42
$850,596
ELECTRICIAN
1
0.05
0.05
$159.50
$2,911
19.42
$56,529
•
SUBTOTAL
$67,516
$1,311,158
CONSTRUCTION
COST OF NEW
EQUIP. & PIPING ($)
% FOR ANNUAL
PARTS
AND SUPPLIES
NUMBER OF LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
PARTS AND
SUPPLIES
PARTS AND SUPPLIES
72,397
5%
$3,620
19.42
$70,298
SUBTOTAL
$3,620
$70,298
TOTAL ANNUAL O&M
?
$397,709
TOTAL PRESENT WORTH
0 & M COST
?
$7,723,500
C-4
?
Suppl. AeratIon
.COST9AsSEPA O&M
TABLE C.4
ANNUAL O&M COSTS FOR CERAMIC DIFFUSER SYSTEM
30 g/s SYSTEM
PRESENT WORTH FACTOR
LIFE,N
20
INTEREST, I
3
INFLATION, j
3
PRESENT WORTH FACTOR
19.42
Energy Cost, $
Average
?
$0.0750 $/kWh
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
(S/day)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
OPERATIONS
ENERGY-ELECTRICAL
.
375
24
9000.0
$675.00
$164,250
19.42
$3,189,735
SUBTOTAL
....
$164,250
.
?
.
$3,189,735
NO. OF
OPERATORS
(per day)
TIME
(hrs/day/operator)
TOTAL TIME
(hrs/day)
LABOR
RATE
($/hr)
ANNUAL
COST
($)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
MAINTENANCE
ROUTINE MAINTENANCE
1
0.1
0.1
$90.00
$3,285
19.42
$63,795
LABOR - OPERATOR
1
0.1
0.1
$90.00
$2,190
19.42
$42,530
ELECTRICIAN
1
0.05
0.05
$159.50
$2,911
19.42
$58,529
SUBTOTAL
$8,9e6
$162,854
CONSTRUCTION
COST OF NEW
EQUIP. & PIPING (5)
% FOR ANNUAL
PARTS
AND SUPPLIES
NUMBER OF LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
(S)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
($)
PARTS AND SUPPLIES
PARTS AND SUPPLIES
389,000
5%
$19,450
19.42
$377,719
SUBTOTAL
$19,450
$377,719
TOTAL ANNUAL. O&M
?
$192,086
TOTAL PRESENT WORTH 0 & M COST
?
$3,730,308
C-5
?
Suppl. Aeration COST9.AsDifluser 90 grass per sec OEM
ANNUAL
TABLE C.5
O&M COSTS FOR U-TUBE 80 g/s
AERATION SYSTEM
PRESENT WORTH FACTOR
LIFE,N
20
INTEREST, I
3
INFLATION, j
3
PRESENT WORTH FACTOR
19.42
Energy Cost, $
Average
?
50.0750 $/kWh
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
($/claY)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
OPERATIONS
ENERGY-ELECTRICAL
89.22
24
2141.2
$160.59.
$39,077
19.42
$758,868
SUBTOTAL
$39,077
$758,868
NO. OF
OPERATORS
(per day)
TIME
(hrs/day/operator)
TOTAL TIME
(hrs/day)
LABOR
RATE(1'
(Or)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
.?
(5)
MAINTENANCE
ROUTINE MAINTENANCE
Blowers
1
0.1
0.1
$90.00
$3,285
19.42
$63,795
Pumps
1
0.1
0.1
$90.00
$3,285
19.42
$63,795
LABOR - OPERATOR
.
Blowers
&
Pumps
1
0.2
0.2
$90.00
$4,380
19.42
$85,060
ELECTRICIAN
1
0.05
0.05
$159.50
$2,911
19.42
$56,529
SUBTOTAL
$13,861
$269,178
CONSTRUCTION
COST OF NEW
EQUIP. & PIPING (5)
% FOR ANNUAL
PARTS
AND SUPPUES
NUMBER OF LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
PARTS
AND SUPPUES
PARTS AND SUPPLIES
3,834,800
5%
$191,740
19.42
$3,723,591
SUBTOTAL
$191,740
$3,723,591
TOTAL ANNUAL O&M
?
$244,677
TOTAL PRESENT WORTH 0 & M COST
?
$4,751,637
C-6
?
Supt. Aeration COST9idsSup. Aer. 80 gifts per sec•O&M
ANNUAL
TABLE C.6
O&M COSTS FOR JET AERATION
80
g/s SYSTEM
PRESENT WORTH FACTOR
LIFE,N
20
INTEREST, I
3
INFLATION, J
3
PRESENT WORTH FACTOR
19A2
Energy Cost, $
Average
?
$0.0750
$40Nh
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
(5/day)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
OPERATIONS
ENERGY - ELECTRICAL
2300
24
55200.0
•
•
?
$4,140.00
$1,007,400
19.42
$19,563,708
SUBTOTAL
$1,007,400
$19,563,708
NO. OF
OPERATORS
(per day)
TIME
(hrs/day/operator)
TOTAL TIME
(bra/day)
LABOR
RATel
(5/hr)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
MAINTENANCE
ROUTINE MAINTENANCE
Pumps
2
0.1
0.2
$90.00
$8,570
19.42
$127,589
Blowers
2
0.1
0.2
$90.00
$6,570
19.42
$127,689
LABOR - OPERATOR
Blowers & Pumps
2
0.1
0.2
$90.00
$4,380
19.42
$85,060
ELECTRICIAN
1
0.05
0.05
$159.50
$2,911
19.42
$56,529
SUBTOTAL
$20,431
$396,788
CONSTRUCTION
COST OF NEW
EQUIP. & PIPING (5)
% FOR ANNUAL
PARTS
AND SUPPLIES
NUMBER OF LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
PARTS AND SUPPLIES
PARTS AND SUPPLIES
3,496,267
5%
$174,813
19.42
$3,394,875
SUBTOTAL
$174,81
$3,394,875
TOTAL ANNUAL O&M
?
$1,202,644
TOTAL PRESENT WORTH 0 & M COST
?
$23,355,351
C-7
?
Suppi. Aeration COST9.xlsSup. Mr. 80 grns
per sec-O&M
TABLE 0.7
ANNUAL O&M COSTS FOR 80 g/s SEPA STATION
PRESENT WORTH FACTOR
LIFE,N
?
20
INTEREST,
INFLATION, I
?3
PRESENT WORTH FACTOR
?
19.42
Energy Cost, $
Average
?
$0.0750 SlkWh
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
($/day)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
OPERATIONS
ENERGY- ELECTRICAL
1988
24
47718.4
$3,578.88
$870,861
19.42
$16,912,117
SUBTOTAL
$870,861
$16,912,117
NO. OF
OPERATORS
(per day)
TIME
(hrs/day/operator)
TOTAL TIME
(hrs/day)
LABOR.
RATE°
($/hr)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
MAINTENANCE
ROUTINE MAINTENANCE
Cut & Landscape
2
0.4
0.8
$90.00
$17,520
19.42
$340,238
Pump Maintenance
1
0.1
0.1
$90.00
$3,285
19.42
$63,795
LABOR - OPERATOR
1
2
2
$90.00
$43,800
19.42
$850,596
ELECTRICIAN
1
0.05
0.05
$159.50
$2,911
19.42
$56,529
SUBTOTA
•
$67,516
$1,311,158
CONSTRUCTION
COST OF NEW
EQUIP. & PIPING ($)
%FOR ANNUAL
PARTS
AND SUPPLIES
NUMBER OF LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
PARTS AND SUPPLIES
PARTS AND SUPPLIES
193,059
6%
$9,653
19.42
$187,460
SUBTOTAL
$9,653
$187,460
TOTAL ANNUAL O&M
?
$948,030
TOTAL PRESENT WORTH
0 & M
COST
?
$18,410,735
C-8
?
Stipp!. Aeration COST9.,dsSup. Aer. 80 grass per sec-O&M
TABLE C.8
ANNUAL O&M COSTS FOR CERAMIC DIFFUSER SYSTEM 80 g/s SYSTEM
PRESENT WORTH FACTOR
LIFE,N
20
INTEREST, i
3
INFLATION,
j
3
PRESENT WORTH FACTOR
19.42
Energy Cost, $
Average
?
$0.0750 $/l(Wh
ITEM
OPERATING
(kW)
TIME OF
OPERATION
(hrs/day)
POWER
USAGE
(kw-hr/day)
ENERGY
COST
($/day)
ANNUAL
COST
(3)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
OPERATIONS
ENERGY-ELECTRICAL
1000
24
24000.0
$1,800.00
$438,000
19.42
88,605,980
SUBTOTAL
$438,000
$8,605,960
NO. OF
OPERATORS
(per day)
TIME
(hrs/day/operator)
TOTAL TIME
(hrs/day)
LABOR
Ramo)
($/hr)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
MAINTENANCE
ROUTINE MAINTENANCE
1
0.1
0.1
$90.00
$3,285
19.42
$83,795
LABOR - OPERATOR
1
0.1
0.1
$90.00
$2,190
19.42
$42,530
ELECTRICIAN
1
0.05
0.05
$159.50
$2,911
19.42
$58,529
SUBTOTAL
$8,386
$182,854
CONSTRUCTION
COST OF NEW
EQUIP.
&
PIPING ($)
%FOR ANNUAL
PARTS
AND SUPPLIES
NUMBER Of LAMPS
REPLACED PER
YEAR (UV ONLY)
COST
PER
LAMP ($)
ANNUAL
COST
(5)
PRESENT
WORTH
FACTOR
PRESENT
WORTH
(5)
PARTS AND SUPPLIES
PARTS AND SUPPLIES
1,037,333
6%
$51,867
19.42
$1,007,251
SUBTOTAL
$51,867
$1,007,251
TOTAL ANNUAL O&M
?
$498,253
TOTAL PRESENT WORTH 0 & M COST
?
$9,676,064
C-9
?
Suppl. Aeration COST9.xlsSup. Mr. 80 gms per sec-O&M