WATER POLLUTION CONTROL RESEARCH SERIES •
                        11020 DNO 03/72
      A FLUSHING SYSTEM FOR
    COMBINED SEWER CLEANSING
U.S. ENVIRONMENTAL PROTECTION AGENCY

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          WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Series describes the
results and progress in the control and abatement of pollution
in our Nation's waters.  They provide a central source of.
information on the research, development and demonstration
activities in the Environmental Protection Agency, through
inhouse research and grants and contracts with Federal, State,
and local agencies, research institutions, and industrial
organizations.

Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Chief, Publications Branch
(Water), Research Information Division, R&M, Environmental
Protection Agency, Washington, B.C. 20^60.

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         A FLUSHING SYSTEM
  FOR COMBINED SEWER CLEANSING
                 by
CENTRAL ENGINEERING  LABORATORIES
        FMC  CORPORATION
         1185 Coleman Avenue
      Santa Clara, California 95052
                 for
OFFICE  OF RESEARCH AND MONITORING
ENVIRONMENTAL  PROTECTION AGENCY
          Program 11020 DNO
         Contract 14-12-466
             March 1972
 For sale by the Superintendent of Documents, U.S. Government Printing Office
           Washington, B.C. 20402 - Price $1.75

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                  EPA Review Notice
This report has been reviewed by the Environmental Protection
Agency and approved for publication.  Approval does not
signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency nor does
mention of trade names or commercial products constitute
endorsement or recommendation for use.
                         ii

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                             ABSTRACT
Because solids deposits in lateral sewers are considered to contribute
a significant quantity of pollutional material to storm water overflows
from combined sewers, the use of a periodic flushing operation was
evaluated as a means of maintaining lower levels of these deposited
materials during low-flow,  dry Weather periods.

Full scale tests were conducted on two variable-slope test sewers (12-
and 18-inch diameters). During the tests,  solids were first allowed
to build up in both test  sewers by passing domestic sewage through the
sewers for durations of 12 to 40 hours and then were removed by
hydraulic flushing.  The results from the tests showed that flush waves
generated using flush volumes ranging from 300 to 900 gallons at aver-
age release rates ranging from 200 to 3, 000  gpm were found to  re-
move from 20 to 90 percent of the solids deposited in the 800-foot long
test sewers.

The cost of installing a periodic flushing system in a typical system of
lateral sewers was estimated to be $620 to $1, 275 per acre.

This report was  submitted in fulfillment of Project Number  11020 DNO,
Contract Number 14-12-466 under the sponsorship of Water Quality
Research, Environmental Protection  Agency.
                                 111

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                           CONTENTS
Section                                                       Page
 I        Conclusions  	      1
                           y-

 II       Recommendations	      3

 III      Introduction	      5

 IV      Design and Construction of the Test Facility	      9

 V       Experimental Operation	    21

 VI      Discussion	,  .    39

 VII      Design and Testing of a Prototype
          Flush Station	    71

 VIII     Arrangements for Field Demonstration of
          Periodic Flushing of Combined Sewer Laterals ...    81

 IX      Acknowledgements	    83

 X       References	    85

 XI      Glossary of Terms	    87

 XII      Appendices	    89

          A.  Results from Shakedown Testing	    91

          B.  Field and Laboratory Procedures	    93

          C.  Results from Flushing Evaluation Tests	   105

          D.  Statistical Analysis of Design Equations	   147

          E.  List  of Design Drawings	   155
          F.  Description of Mathematical Model for Design
              of Sewer Flushing Systems	   159

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                           FIGURES
                                                               age
 1     Periodic Sewer Flushing Test Facility ...........   12

 2     Flushing Evaluation Flow Diagram .... ..........   13

 3     Clear Plastic Pipe Section in 12 -Inch Sewer ........   14
                                     »
 4     Influent Supply and Control System ..............   15

 5     Effluent Collection and Recirculation System .......   16

 6     Flush Tank with Pneumatically  controlled
       Discharge Valves ..........................   18

 7     Flush Control Building ......................   18

 8     Sewage Flow Rate Hydrographs Used in Solids
       Build-Up Tests  ...........................   32

 9     Inflatable Dam ....................... .....   33

10     Relative Effect of Slope and Flow Rate on the
       Distribution of Solids in the Test Sewers  ..........   40

11     Typical Correlation of the Independent
       Variables to  C__   .........................   42
12     Suspended Solids Cleansing Efficiency Correlation  ...   45

13     Volatile Suspended Solids Cleansing Efficiency
       Correlation ..............................   47

14     Total Organic Carbon Cleansing Efficiency
       Correlation  .............................   48

15     Wave Depth Correlation for 12-Inch Sewer .........   50

16     Wave Depth Correlation for 18-Inch Sewer .........   51

17     Sewage -Flush Correlation ....................   53
                                vn

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FIGURES (Continued)

18
19
20
21
22
23
24
25
26
27

28

29

30


Pipe Joints Misalinement Effects
Grade Misalinement Effects 	
Relative Distribution of Solids Deposits 	
Time -Series Build -Up of Solids 	
Alternate Flushing Station Designs 	
Prototype Flush Station 	 ,
Prototype Flush Station Control and Operation . . . ,
Proposed Fabric Bag Flush Station 	
Proposed In-Line Dam Flush Station 	
High-Range and Low-Range Correlation of
BOD with TOG for GEL Sewage 	
Accuracy of High-Range Correlation of
BOD with TOC for GEL Sewage ....
Accuracy of Low-Range Correlation of
BOD with TOC for GEL Sewage . .
Accuracy of Simplified Correlation of
BOD with TOC for GEL Sewage 	
Page
55
56
59
61
72
73
75
78
79

. . 99

100

. . 101

. . 102
        Vlll

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                             TABLES


No.                                                          Page

  1     Solids Removal Predictions	  68

  2     Estimated Flushing Costs	  69

  3     Results from Friction Coefficient Tests	  91

  4     Results from Hydraulic Mixing Tests Using Sewage  • •  •  91

  5     Results from Hydraulic Mixing Tests Using Fine Sand.  •  92

  6     Summary of Accuracy of BOD -TOC Relationships .... 103

  7     Summary of Results from Solids Distribution Tests  ... 105

  8     Summary of Results from Clean-Water Flush Tests  ... 106

  9     Summary of Maximum Flush Wave Depths Observed
       in 12-Inch Sewer	115

 10     Summary of Maximum Flush Wave Depths Observed
       in 18-Inch Sewer	127

 11     Summary of Steep-Slope Equation Verification	139

 12     Steep-Slope Check of Wave Depth Equation
       (Equation 13A)	140

 13     Results from Sewage-Flush Correlation Tests	141

 14     Results from Pipe Misalinement Tests	143

 15     Results from Flush Wave Sequencing Tests	144

 16     Results from Solids  Build-Up Tests	145

 17     Results from Prototype Flush Station Tests	146

 18     Summary of Statistics for Equation 9	147

 19     Summary of Statistics for Equation 10	148
                                 IX

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                       TABLES (Continued)






No.                                                             Page
 20     Summary of Statistics for  Equation 11 ...........




 21     Summary of Statistics for Equation 12 ...........   149





 22     Summary of Statistics for Equation 13A  ..........   150





 23     Summary of Statistics for Equation 13B  ..... .....   151





 24     Summary of Statistics for Equation 15 .......  ....   152





 25     Summary of Statistics for Equation 16 ...........   153

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                              SECTION I

                            CONCLUSIONS

1.  Satisfactory predictions can be made of several cleansing efficien-
cies and wave depths for the flush waves and sewer sizes  studied using
the formulas developed in this project.

    a.   The percentage  removal (cleansing efficiency) of deposited ma-
terial by periodic flush waves is dependent on the following variables:
flush volume, flush discharge rate,  sewer slope, sewer length, sewage
flow rate,  and sewer diameter.

    b.   Cleansing efficiency is dependent on flush discharge rate and
volume but is not otherwise significantly affected by details  of the flush
device inlet to the sewer.

     c.   Slight irregularities in sewer  slope and pipe  alinement do not
significantly affect the percent cleansing efficiency.

     d.   Use of settled sewage as the flushing liquid causes  only a minor
and predictable reduction in cleansing efficiency.

2.   The mathematical design model developed in this project provides
an efficient means of selecting the most economical flushing system to
achieve  a desired cleansing efficiency within the constraints set by the
engineer and limitations  of the design equations.

3.   Where sewers are over 8 ft deep, tanks inserted  in existing
manholes will usually provide adequate flush volumes for  periodic  sewer
flushing.

     a.   The prototype flush station developed in this  project can be in-
serted in a manhole and provides the functions necessary  to pick up
sewage from the sewer,  store it in a coated fabric tank and releas-e the
stored sewage as a flush wave upon receipt of an external signal.

4.  An estimate of the costs of periodically flushing combined sewer
laterals  indicated a range of costs from $630 per acre to  $1,275 per
acre for average  removal efficiencies of  6t percent and 72 percent,
respectively.

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                              SECTION II

                        RECOMMENDATIONS

This project has succeeded in developing an engineering basis for peri-
odic sewer flushing of combined sewer laterals within a limited size
range.  It is recommended that further  studies be made for flushing of
larger sizes of pipe,  of wave sequencing, and of  solids buildup over
longer time periods.   Although some of the additional work can be done
in the existing test facility,  a demonstration in an operating combined
sewer system will be  required to verify the relationships developed to
date and to extend the range of the correlations.

Some of the more important areas which need further investigation are
listed below:

     1.   Investigate the downstream redeposition of the solids removed
by flush waves in the upstream section  of the sewer.

     2.   Experimentally develop the flow hydrograph (wave depth as a
function of pipe length and time) associated with the various flush waves
investigated during this study and establish a correlation between these
hydrographs and the cleansing efficiency relationships.

     3.   Investigate the effect of multiple flush -wave release on the flush
wave hydrographs.

     4.   Study the  diurnal  deposition and resuspension patterns  of various
dry weather sewage flows.

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                            SECTION III

                           INTRODUCTION

BACKGROUND AND PURPOSE

Other studies have shown the need to minimize pollutional effects of
stormwater overflows from combined sewer systems.  Even though
stormwater provides dilution of sanitary waste, Biological Oxygen De-
mand and suspended solids of the sewage are often very high during
storms  when flow is typically diverted to natural water courses.

This project attempts to improve the quality of the combined sewage
flow as  an alternative to retention of storm flow or treatment of the over-
flow at the outfall. It appears that in many cases the high pollutional
load of the combined sewage flow is caused by the flushing out of solids
•which had settled in the sewer during the low flow of dry weather.   The
purpose of periodic sewer flushing as applied to combined sewers is to
remove  settled material during dry weather and hydraulically  convey it
to the treatment  plant.  To the degree that this purpose  is accomplished
the pollutional load of the combined sewage will be reduced. Only that
sanitary sewage  produced during the storm would have to be bypassed
rather than also  bypassing a major portion of the  sewage solids produced
prior to the storm.

PROJECT APPROACH

The program for study of the feasibility of a periodic flushing  system for
combined sewer  cleansing has been divided into the following major
phases.

    PHASE I - Feasibility Study,  Planning,  and Preliminary Facility
Design.   This phase was funded under FWPCA Contract No. 14-12-19
completed in  1967-  On the basis  of literature review, field surveys,
and limited experimental work, there was  a strong indication of the
feasibility of this technique.

    PHASE II - Flushing Evaluation.   This phase was funded under
FWQA Contract No.  14-12-466 and is the subject of this report.  This
phase includes preparation of a test facility, hydraulic experiments,  and
prototype equipment.

    PHASE III -  Demonstration in a Combined Sewer System.   This
phase will be required to show the application of periodic flushing tech-
niques and their  effect on the discharge from a portion of a combined
sewer system.
                                   5

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OBJECTIVES OF PHASE II

The objectives of this phase are:

 •  To experimentally determine the hydraulic requirements for effec-
    tive cleansing of combined sewer laterals and to formulate design
    rules and criteria for application of periodic flushing equipment to
    existing combined sewer systems;

 •  To develop a prototype of a unit-flushing-station which would be
    applicable for demonstration of periodic flushing in a combined
    sewer system; and

 •  To expedite and promote arrangements for a demonstration as  Phase
    III of this program of periodic flushing of laterals in a  combined
    sewer system.

SCOPE OF PHASE II
This step of the project provided for preparation of a test facility, con-
duct of flushing experiments, evaluation of experimental results, and
development of a mathematical design model for application of flushing
equipment to combined sewer systems.

Test Facility

The scope of the experimental study was limited to combined sewer
laterals  of low slope with low sanitary sewage flow.  Accordingly, the
test facility required only two  sizes of pipe with a moderate length and
limited slope capability.  The  flush tank sizes were limited to a volume
thought to be practical in an actual system.   Means were provided for
supply of sanitary sewage to the test pipes for solids deposition purposes.

Flushing Experiments

The basic philosophy of the flushing experiments was to provide the infor
mation for an engineering application of flushing.   Therefore, the scope
of the  experiments was limited to a measurement of what flowed into the
sewer prior to flushing, the flushing conditions,  what was removed by
flushing  and what remained that could be removed by a simulated storm
flow.

Such subjects as a complete description of deposition from sanitary
sewage flow, of the  flush wave hydraulic patterns,  and of the interaction
of the  flush wave and the  sediment layer,  and of the effects on main and
trunk sewers are not included  in the scope of the flushing experiments.

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Evaluation of Experimental Results

The relationships between the experimental variables were to be esti-
mated using appropriate statistical techniques.

Formulate Mathematical Model

The mathematical model was to be developed for design purposes.  It
was not to be a general mathematical description of the sewer system
nor extend beyond the laterals.  The model was to predict performance
of flush tanks applied to sewer laterals based on the  experimental re-
sults,

Development of Prototype Flush Station

This step includes study of conceptual designs  of flushing equipment and
design construction and testing of one  type of flush station which is ex-
pected to be needed for a flushing demonstration.

Arrangement for a Flushing Demonstration

This step provided for furnishing information needed to plan a periodic
flushing demonstration for Hammond,  Indiana,  and for promoting that
demonstration.  It also provided for canvassing up to four other poten-
tial demonstration locations in the  event that Hammond decided not to
apply for a demonstration grant.

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                             SECTION IV

       DESIGN AND CONSTRUCTION OF THE TEST FACILITY

DESIGN  OBJECTIVES AND APPROACH
The overall objective of this phase of the project was to design and con-
struct a test facility that could be effectively used to determine the re-
quirements and limitations associated with the hydraulic cleaning of
combined sewers.   The primary objective of the project was to study the
cleansing of lateral sewers with mild slopes.   As a result, the design of
the facility was limited to relatively small diameter pipes and slopes
between 0. 001 and 0. 01.

The fact that pipe diameter and pipe slope were considered to be of pri-
mary importance in the experimental work of this project greatly
influenced the  overall design.of the facility.  A minimum of two diameters
of pipe had to be included to allow an effective comparison of pipe diam-
eter effects.  The  12 in.  and 18 in. diameters were selected because they
were representative of the  range of small diameter sewers (8 to 24  in. ).
Establishment of the relative influence of pipe slope on the cleaning pro-
cess required that the design allow for independent  slope adjustment of
the two sewers,  with a minimum of effort.

Since the primary concern  of the proposed experimental work, was with
solids deposited by sewage flowing through the sewers,  the design had to
include a complete  sewage  supply and control system.  Also  reliable
sampling systems were needed so that the quality of the influent to test
sewers as well as the discharge from each pipe could be accurately
evaluated.

Hydraulically cleaning the sewers required that flush equipment capable
of supplying known quantities of flush liquid at various rates to different
points along the length of each  sewer be included in the facility. Also
the design had to include a  system capable of  separately cleaning individ-
ual sections  of each test sewer to a consistent degree,  in order to provide
a constant reference for comparing the effectiveness of  the various flush
combinations and to establish the influence of pipe length on the cleansing
process.

The objectives and requirements discussed above were combined with the
economic and test site limitations of the project to produce a facility de-
signed to meet the experimental needs of the project.  A detailed descrip-
tion of the facility is given later in this next section.

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PROBLEMS ENCOUNTERED

There were several problems encountered during the design and co
struction phases of this project which would be helpful to know abou
another facility of this type is ever constructed.  Most of the pro
encountered during the mechanical design phase were satisfactor y
solved and can be avoided by using the general arrangement descri e
later in this section. Although  the problems encountered during the con-
struction phase were not  too serious, several of them cause      f
delays.

The  problem that caused  the most concern was the result of the high
length tolerances of the vitrified clay sewer pipe.   Despite careful
grading of the pipe purchased, the effective length of the 18 in.  section
                                                      •  i  j J.TA  1*3 *
varied from near nominal to as much as 3 in. over nominal and tne 1
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Variable-Slope  Test Sewers

The pipeline assembly (see Figures 1 and 2 ) consists of two pipes that
run parallel to each other.  Each pipe is supported along  its entire length
by an I-beam.  Attached to the top of each beam is a series of pipe  saddles
in which the pipe rests.   The two I-beams are suspended between the legs
of fabricated steel frames by means of long screws.  Each  beam spans
the distance between two consecutive  frames and is connected to the next
beam by means of a single pin, making the connection flexible  in the ver-
tical direction.  The screws which support the beams are attached to the
top of the steel frames in such a manner as to allow the screws to be
used to adjust the vertical heights of the  beams.  The two pipe lines are
separately supported and their slopes can be independently  adjusted.

Between the two pipelines,  a  wooden catwalk runs the entire length of the
pipeline assembly.   The walk is supported by the I-beam  which supports
the larger of the two test pipes.   Since the position of the catwalk and the
test pipes remains relatively constant, it provides easy access to the test
pipes at all heights.

The test sewers  are constructed of 12 in. and 18 in.  clay sewer pipe.
Each line is approximately 800 ft. long and  consists of about 620 ft.  on a
straight-run and 180 ft.  on a  curve.   (Approximately 300  ft. of straight
run is upstream of the curve  and the  remainder downstream. )   At the
beginning and at the third point along each pipeline,  there are fabricated
steel sections that  simulate manholes.  In every 18 ft. section of pipe,
with the exception of the curved section,  there is one tee  with a 12 in.
side outlet this is positioned vertically to allow visual observation of
flow in the pipeline.  Also, a section of clear plastic pipe (6 ft. long in
the 18 in. sewer and 5 ft.  long in the 12  in.  sewer) was used to replace a
section of clay pipe in both test sewers to allow more extensive visual
observation of the flow in the pipes (See  Figure 3).  These plastic sections
have the same inside diameter as the clay pipe and are presently located
approximately 140 ft. downstream of the influent end of the sewers.

The test pipes can  readily be adjusted to virtually any slope desired be-
tween the limits  of 0 and 0. 01.  Slope changes are accomplished by ad-
justing the  screws which support the pipe at each support frame.  The
adjustment of the screws is easily accomplished through  use of an air
driven wrench.   This system allows complete slope changes to be made
in a matter of only a few hours.
                                   11

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Figure 1   PERIODIC  SEWER  FLUSHING TEST FACILITY

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SANITARY SEWER
(City of Santa Clara)
                                 'COMMINUTOR!
1
*2 — CHICAGO
PUMP NON-CLOG
SEWAGE PUMPS
i
\


FLOW
CONTROLLER
I
                                                                PARSHALL FLUME
                                                                (3" ACCURA-FLO)
•H
CHICAGO PUMP
TRU-TEST
SEWAGE SAMPLER
                    1 SAMPLE BOTTLEj
                FLOW
                SPLITTER
                                      SOLIDS SLURRY
                                      FEEDER #2
                                                        DRY SOLIDS
                                                        FEEDER
SOLIDS SLURRY
FEEDER #1
        »]l8" TEST SEWER
          12" TEST SEWER]
  FLUSHING SYSTEM
                               CONE— BOTTOMED
                               COLLECTION TANK
                               3150 GALLON
                               MAXIMUM CAPACITY
                                                           CONE — BOTTOMED
                                                           COLLECTION TANK
                                                           3150 GALLON
                                                           MAXIMUM CAPACITY
                                                    1
                                            CHICAGO PUMP
                                            MODEL VPMOM 4
                                            NON-CLOG PUMP
                                                                       PROPERTY OF
                                                                     FMC CORPORATION
                Figure  2   FLUSHING EVALUATION FLOW DIAGRAM

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            Figure  3   CLEAR  PLASTIC  PIPE SECTION
                       IN  12 IN.  SEWER

Influent Supply and Control

The sewage supplied to the Flushing Evaluation Facility is taken from an
18 in.  sewer line that belongs to the City of Santa Clara, California.   The
sewage is transported by gravity through a 12 in.  clay sewer line  into a
wet well at the bottom of a  concrete pump pit.   The sewage is then pump-
ed from the wet well through  a 6 in.  C. I. line by means of  one or both of
two nonclog pumps, to a point where the flow is divided and part of the
flow is diverted to  other FMC experimental projects.  The flow not di-
verted to the other projects passes through a 6  in. pressure line to the
beginning of the Flushing Evaluation Facility.


The influent supply and control system of the test facility is shown in
Figure 4 .  The influent enters first  a flow control box where the portion
of flow desired for testing is  diverted into a 10  in. wide fabricated steel
flume.  The portion of flow not needed for testing is wasted back to the
city sewer.   The influent passes from the  10 in. flume through a 3 in.
Parshall flume where the rate of flow is recorded and controlled by a
float-activated flow meter and pneumatic controller.  The  flow through
the  Parshall flume is  recorded on a single pen, 24 hr. circular chart.
The pneumatic controller can be manually set for a desired flow rate,
which can be adjusted by the  operator at any given time.
                                  14

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                        DRY
                        SOLIDS
          FLOW CONTROLLER FEI:DER
TIMERS FOR
SOLIDS FEEDERS
        Figure 4   INFLUENT SUPPLY AND CONTROL SYSTEM

The controller continuously compares the actual flow as measured by
the flow meter with the value set by the operator and corrects for any
difference by sending the proper pneumatic signal to the pneumatic
lever motor,  which actuates and corrects the position of the flow di-
verter.

The effluent from the Parshall flume passes through approximately 19
ft.  of fabricated steel flume 7 in. wide and approximately 6 ft. of flume
18 in.  wide, all on a slope of 0. 67 percent, to a fabricated steel splitter
box where the total test flow is divided between the two test pipes.   The
splitter is manually operated and is capable of dividing the total flow in-
to any two proportions desired.

The quality of the influent to the test facility can be altered by the
addition of foreign materials such as sludge,  paper,  etc.  Solids in the
form of slurries can be added to the influent by use of one or both of the
two available  solids feeders (See Figure 2).  These feeders each consist
of a 40 gal. steel fabricated circular storage tank and a vertically acting
dipper, actuated by a single solenoid air cylinder.   The maximum feed
rate of each of these feeders is more than 6. 0 Ib. per min.  The 30-min.
timer  gives the feeder almost infinite feed rate control.

Dry solids such as sand and gravel, can be added to the influent by
means of the dry solids  feeder assembly.  This assembly consists of a
20 gal. cone-bottomed hopper that discharges into a Syntron vibratory

                                   15

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feeder.  The flexibility of the  speed controller on the Syntron feeder
combined with that of the 30 min. cycle timer makes the feed rate of   e
assembly almost infinitely adjustable from 1,250 Ib. per hr. to zero.

The influent to the test sewers can  be  sampled either continuously or
intermittently.  A dipper type composite sampler is installed in the 7 in.
wide steel flume between the solids feeders and the flow splitter box.
The sampler is driven by a 2 rpm electric  motor that is coupled to a 30
min. cycle timer.  The timer allows the sampling frequency to be ad-
justed  from a low of  1 per  hr. to a maximum of  120 per hr.

Effluent Handling Equipment

The catch  basin assembly (See Figure 5) is completely contained within
a concrete pit 14 ft.  wide,  24  ft.  long, and 12 ft. deep.  This portion of
the test facility was  specifically designed for handling  and sampling the
effluent from the test pipes.
               Figure 5   EFFLUENT  COLLECTION  AND
                          RECIRCULATION SYSTEM
                                       16

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There are two steel cone-bottom collection tanks that have a maximum
capacity of approximately 3, 150 gal. each. On top of these two tanks
are two troughs that are  gated such that either pipe  can be discharged to
either collection tank  or wasted to the city sewer.

On the floor  of the pit below the collection tanks is a 20 hp nonclog pump
designed to pump 800  gpm at a  total discharge head  of 67 ft.  The pump
is incorporated into a 6 in. piping and valving  system that is designed to
perform the  following three separate  tasks:

   1.  The pump can  be used to pump the contents of either or both
collection tank(s) to the city sewer by way of an 8 in. waste sewer.

   2.  It can also be used to hydraulically mix the contents of either  tank
by rapid recirculation.  The contents of the tank can be circulated by
pumping from the top  and into the bottom or vice versa.

   3.  The contents of either or both tanks can also be pumped to any
one of seven possible  locations  along  the test  sewers and discharged into
either test pipe at each location.   This  arrangement makes possible con-
tinuous recirculation of effluent from either test pipe.

Flushing System

Experimental flushing operations can utilize any one or all of three avail-
able elevated flush tanks  (Figure 6).   The flush tanks are constructed
of steel and are designed such that they can be pressurized up to 20 psig.
The primary flush tank is the largest, 5 ft in diameter and 6 ft high with
a capacity of 900  gal. , and is located at the influent end of the test pipes.
The  other  two tanks are also 5 ft in diameter,  but only 5 ft in height.
One  of the smaller tanks  is located approximately 1/3 of the total dis-
tance downstream from the primary tank and the other 2/3 of the way.
All three  of the tanks  are elevated above the test pipes allowing gravity
flushing.

The  release  of water from each flush tank is controlled by a  12 in.  and an
18 in.  butterfly valve.  The 12  in. valve is installed in a  12 in. steel pipe
which runs down from the flush tank and discharges  into the larger test
pipe.   The 8 in. valve  is  installed in an 8 in. line which runs down from
the flush tank and discharges into the smaller test pipe.

The flush control valves are actuated by double-acting  air cylinders equip-
ped with pneumatic positioners.  The flush control valves  can be actuated
either manually or automatically. The controls used for manual and  auto-
matic control of the valves are  located  on the  instrument panel in the con-
trol building  located near the catch basin (see  Figure 7).

                                 17

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Figure 6   FLUSH TANK WITH  PNEUMATICALLY
           CONTROLLED DISCHARGE VALVES
     Figure 7   FLUSH CONTROL BUILDING
                            18

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The valves are operated manually by opening the control line to the de-
sired flush valve and transmitting a pneumatic signal to it by means of a
pressure regulator.  The control valve is completely closed when the
pneumatic signal is 3  psig,. and completely open when the signal is 15
psig.    The percentage change in the signal is directly proportional to
the percentage change in valve  opening.  The control valves at each tank
can be manually operated independently of those at the other tanks.   The
8 in.  and 12  in.  valves at each  tank  can be operated independently only if
they are operated at different times.  If both valves are to be operated
simultaneously, they must be operated using the same pneumatic signal.

All of the flush control valves can be automatically controlled by means
of a circular cam programmer.  This programmer is electrically driven
at one revolution per 8 min. and produces a pneumatic  signal •which is
used  as the set point for a pneumatic controller, which continuously ad-
justs  the valve being used to obtain the liquid level desired.   The water
level  in each tank is continuously monitored by a differential pressure
transmitter with a fixed operating range of  0 to 100 in.  of water.  The
transmitter  receives the difference in pressures between the bottom and
top of the flush tank (-water level) and converts this pressure to a pneu-
matic signal (3 to 15 psig) which is transmitted to the pneumatic recorder
and controller.

The 8 in. and 12 in. control valves at the flush tanks can be automatically
operated independently or simultaneously.  However, only those valves that
are to be operated under the same control sequence can be  operated sim-
ultaneously.  If the control sequence is different for different valves, each
of these valves must be operated separately.

The recorder that  receives the signal from the transmitter is a three-pen
(one for each tank), strip-chart-type pneumatic recorder.  The recorder
continuously monitors the liquid level in all three flush tanks.  The signal
received by the controller is the actual liquid level in the flush tank and
is compared by the controller with the desired liquid level as indicated by
the cam programmer.  If a difference in the actual and desired liquid
levels is present, the  controller pneumatically adjusts the valve to  com-
pensate for the difference.
                                   19

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                             SECTION V

                     EXPERIMENTAL OPERATION

SHAKEDOWN AND PRELIMINARY TESTING

The 2-week period immediately following completion of the construc-
tion of the experimental equipment was used to ready the facility for full-
scale testing.  During this period, the experimental equipment was oper-
ated and adjusted for proper function and the tentative test procedures
were  checked experimentally to establish their reliability.

Equipment Check

The sewage supply equipment was checked for proper operation and
accuracy.   This  was accomplished by collecting the total discharge from
the test sewers in the calibrated collection tanks and recording the actual
flow rate and fluctuation in flow rate as indicated by the time-rate-of-
change of the volume of effluent collected.  The flow rate recorded by
the influent flow  recorder was found to correlate satisfactorily (within
3 percent) over the expected operating flow range of 10 gpm to 100 gpm.
The flow controller,  after minor  adjustments were made, was found to
be capable of maintaining constant rates  of flow, in the above range, with
only minor fluctuations  of extremely short duration.  The flow splitter
was checked and found to be capable of dividing the flow between the two
test sewers within -j- 1 percent of  the desired proportions.

The flush control system was adjusted to obtain constant discharge  rates
and the tank level recorder was calibrated.   These adjustments •were
accomplished by making numerous flush releases using total flush vol-
umes ranging from 200  to 900 gal.  The  accuracy of the tank level
recorder was checked by direct measurement of the tank volume and
level  and found to be satisfactory ( + 0. 5 percent over the given range).
The discharge rate was  verified using the calibrated tank level recorder.

The solids feeders were adjusted and feed rate of each established.  The
dry solids feeder was operated using uniformly-graded clean sand and
the maximum feed rate  was found to be approximately 1, 250 Ib. per hr.
for continuous operation.  The slurry feeders were operated using a
water-paper mixture and their maximum feed rates were found to be
approximately 6. 7 Ib. per min.   Note should be taken that although
these solids feeders were installed and calibrated,  the suspended solids
content of the influent sewage remained consistently high throughout the
testing and therefore they were not required during any of the actual ex-
perimental work.

                          21

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Friction Coefficient Evaluation

The two test sewers were adjusted to the slope values (0. 001 for   e
in.  sewer and 0.002 for the 12 in.  sewer) selected as the minimU^5_lulic
be used in the proposed testing program, and a series of basic  y  r
tests  was  run using clean water.  This test series had two objectives.
The first was to check the actual discharge of the 20 hp  recirculation
pump at various discharge heads and the second was to experimenta y
check the flow characteristics of the clean sewers.   The recirculation
pump was used to pump clean water at various constant rates to the up-
stream end of the test sewers  and the depth of the flow and corresponding
average discharge rate were recorded for each sewer.   The measure-
ments of the depth of the flow were made using a graduated depth gate at
several different points along each sewer.  The average discharge rate
was determined by collecting 2, 850 gal.  of the discharge from each test
sewer in the effluent collection tanks and recording the total elapsed
time.

The results from the above tests (see Table 3, Appendix A) indicated
that the performance of the recirculation pump closely followed the
published performance curve,  and that the Manning's-n values for the
clean sewers ranged from 0. 008 to 0. 0135.   The Manning's-n values
were  generated by solving Manning's Equation (Equation 1) for n using
the experimentally determined flow rate and flow-depth data.

                                        R2/3   A             (1)
Where:

      Q   is the average discharge in cubic ft. per sec.
      n   is the empirically determined friction coefficient,
      S   is the slope of the pipe in ft.  per ft. ,
      R   is the hydraulic radius in ft.
      A   is the cross-sectional area in sq. ft.

Although the tests were not precise enough to be all conclusive,  the
values obtained show good correlation with those usually used for clean
vitrified clay pipe.

Effluent Mixing Evaluation

Several tests were conducted to establish the overall efficiency and re-
liability of the proposed effluent mixing and sampling procedures.   The
reliability of these procedures  depend almost exclusively on the ability


                                  22

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of the hydraulic mixing process to produce a mixture which very closely
approximates a homogeneous mixture, without significant modifications
in the characteristics of the particulate matter present.

The circulation patterns developed by the mixing process were visually
evaluated by mixing various volumes of clean water (1, 200 to 2, 850 gal. )
and introducing small amounts of Methylene Blue at several different
points  in the collection tank.  In all cases,  the circulation patterns
appeared  to be uniform throughout the tank and appeared to produce com-
plete dispersion of the dye within one complete volume displacement.

The homogeneity of the mixture produced by the mixing process was
checked by mixing given volumes of water containing known quantities of
the fine sand, taking depth integrated grab  samples after various mixing
times,  and analyzing these samples for suspended solids concentration.
The results of these tests (Table 5, Appendix A) show that the suspended
solids'concentrations  of the grab samples taken after one and two volume
displacements were consistently within 2 percent of the expected values.

These  results indicate that the mixing required for representative sam-
pling is accomplished by the recirculation operation when mixing times
that are equivalent to  one or more volume displacements are  used.

The character of the particulate matter presented in sewage was found
not to be  significantly altered by the mixing process.  Several quantities
of sewage of known suspended solids concentrations were placed in the
collection tanks and mixed continuously for  one and two complete volume
displacements.  In each case, the suspended solids concentrations of the
samples taken after mixing were consistently within 5 percent of the sus-
pended solids concentration of the composite sample taken before the
sewage was mixed (see Table 4 ,  Appendix A).

Sand Transport Test

The distribution of solids deposits along the length of the two  test sewers
was visually evaluated.   This was accomplished by using the dry solids
feeder to  add approximately 200 ppm of uniformly graded fine sand to
clean water passing through the  18 in.  and  12 in. test sewers at 50 gal.
per min.  and 30 gal. per min. ,  respectively, and observing the resulting
deposits of sand at various points along the  sewer.

More than 50 percent  of the  sand appeared to  settle out in the first 100 to
150 ft,  of the pipe.  .Significant quantities  of  sand could be resuspended
and transported only by flush waves generated by flush releases of 300
gal. or more at flush  rates of 500 gpm and greater.  The amount of sand

                                  23

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resuspended appeared to be more dependent upon the rate of flush release
than on the volume of release, whereas the distance the sand was carried
after resuspension appeared to depend more  on the volume of the flush
release.

Preliminary Flushing Evaluation Tests

Several preliminary flush tests were run to establish a realistic and
workable plan of attack.  During the first few of these tests, no sewage
was used.  Instead, clean water was used and the  general characteristics
of flush waves generated by various combinations  of volume and rate  of
release were observed.   Also, the time required for completion of the
various testing operations was established to allow better time planning
for future testing.

The second portion of these preliminary tests was run using sewage and
in accordance with the preconceived test operational methods.  Although
data was gathered during these tests,  it was not used in the final evalu-
ation due to procedural errors and changes made during this learning
phase.   These tests  served to increase the efficiency and reliability  of
the final test procedures, which will be described in the following section.

TEST PROCEDURES
The experimental work performed during the course of this project was
designed and organized to empirically define the physical limitations and
requirements associated with hydraulic cleansing  of small sewers.  The
major portion of the work was directed at defining the relative influence
of the various experimental parameters (flush rate, flush volume, pipe
diameter,  pipe slope,  pipe length, and sewage base flow) on the efficiency
of the cleansing process, with physical conditions such as pipe  alinement
and slope uniformity optimized.   The remainder of the experimentation
attempted to evaluate the changes in the cleansing efficiency when the
various physical conditions were  somewhat less than optimum.

The overall testing plan consisted of eight general groups of tests.
Although each of the test groups had  different objectives,  all of them were
operated in the same basic manner.  The following discussion will first
describe the general operational procedures common to most of the tests,
and then discuss  in more detail the specific operation of each of the groups
of tests.
                                  24

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Basic Operation

Solids  Buildup.   The first step in nearly all of the tests run during this
project was to build up solids in the test sewers.  This was accomplished
by adjusting the influent flow controller to maintain a constant flow rate,
usually between 40 and 60 gpm,  and setting the flow splitter  to attain
the desired apportionment of the total flow between the two  test sewers.
The selected sewage base flow was then allowed to continue flowing
through the sewers for a specific length of time  and was continuously
sampled by the composite sewage sampler before  entering the sewers.
No solids were externally added to the sewage since the solids content in
the sewage remained high enough for adequate solids buildup.   This also
avoided difficulty associated with correlating the quantity and quality of
solids  added to actual field  conditions.  The solids buildup periods
usually extended from early afternoon until early the following morning,
giving  average durations of between 12 and 20 hrs.    However,  approxi-
mately one-fifth  of these buildup periods extended over weekends and
therefore had correspondingly longer duration times.  Not in all cases
was the sewage base flow held constant throughout the buildup period.
This inconsistency resulted from the fact that during the early morning
hours, the supply of domestic  sewage was often not sufficient to  main-
tain the flows desired and the flow would cease.  When this stoppage df
flow occurred, the duration time was taken as the  time during which the
sewage was actually flowing, based on the records from the flow recorder.

Pretest Preparation.  Before the flush waves were released,  several pre-
test operations were performed.  First the sewage flow recorder chart
was checked for  any indication of abnormal flow conditions.   Thus,  if the
solids  buildup flow discontinuities were not excessive, the depth of the
sewage base flow was measured and the general appearance and  quantity
of the  solids deposited was  recorded at several points along the  length of
each of the test sewers.

The maximum depth of the flush waves generated by the various  com-
binations of the test variables was measured at  several pdsitions along
each sewer.   This was accomplished by inserting  quarter-inch diameter
steel rods, coated with a paste-type water level indicator,  into the up-
turned tees at approximately 60  ft. intervals before release of the flush
wave.  Then after the flush waves had passed all of the stations, the rods
were individually removed and maximum wave depth recorded by meas-
uring the maximum depth shown by the water-level indicator.  The accu-
racy of these measurements is estimated to be within +_ 1/4 in. ;  with  the
majority of the reading being slightly higher than  the actual depth.
                                  25

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Flush Release.  The flush release, when included in the test, was made
immediately after the end of the solids buildup period.   A given quantity
of flush liquid, usually 300 to 900 gals,  was placed in the primary flush
tank located at the upstream end of the test sewers.  Then the sewage
base flow to the 12 in. test sewer was shut off and at the same instant
the flush release was made to the 12 in.  sewer.  Then the flush tank was
refilled and the above process repeated for the 18 in. sewer.  When the
first appearance  of the flush wave, indicated by an increase  in depth of
flow, was observed at the effluent end of the  sewers, the discharge was
diverted from waste to one of the cone-bottomed collection tanks (one for
each sewer).

After collecting the complete flush discharges, the contents  of tanks
were individually mixed,  using  the hydraulic mixing process previously
discussed, and samples  of each taken for laboratory analysis.  Also the
total volume  of each flush discharge was recorded by reading the  corres-
ponding tank-level indicator.  When the flush volumes being  investigated
were small,  clean water was added to the collection tanks before  they
were mixed,  in order to allow use  of the recirculation mixing process.

Storm Simulation.  The storm simulation  step was the final cleansing
which the test sewers received  in all of the tests.  The flow  rate used
was in all cases approximately  1, 000 gpm, the maximum allowed by the
pumping system, and was designed to clean the sewer to the highest
degree possible.

The first section of the 12 in. sewer was  cleaned by pumping clean water
from one of the cone-bottomed collection  tanks to a point approximately
160 ft from the downstream end and collecting the total discharge from
the sewer in the  remaining collection tank, where it was mixed and sam-
pled.   The tank containing the discharge from the sewer was emptied and
cleaned, and the  other tank was again filled with clean water.  Then the
process was repeated for the downstream 160 ft of 18 in. sewer.

After cleaning the first 160 ft downstream section of each test sewer, in
the manner described above,  the flow induction point was moved up-
stream another 108 ft and the next 108 ft  section of each sewer was like-
wise cleaned.  Then the flow induction point was  moved upstream another
260 ft along the 18 in. sewer and 247 ft  along the 12 in.   sewer and the
next corresponding sections of  each sewer cleaned.  Finally the flow in-
duction point was moved to the upstream end of each of the sewers and
the last or upstream 267  ft section of each pipe cleaned.
                                 26

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Solids Distribution Tests

The purpose of this group of tests was to establish the relative distribu-
tion of the  solids along the length of the test sewers as deposited by the
various sewage base flows.  These  tests were generally conducted as
described in basic operation section above,  except that no flush release
was made.  Instead,  the test sewers were cleaned using only the storm
simulation process.

At the minimum  slope values of 0. 001 for the 18 in. sewer and 0. 002 for
the 12 in. sewer, a total of six tests were run on each sewer.  Two tests
were  run for each of the sewage base flows  of 10,  30,  and 50 gpm for the
18 in.  sewer and 10, 20, and 30 gpm for the 12 in.  sewer.

At the slopes of 0. 002 and 0. 004 for the 18 and 12 in. sewers,  respec-
tively,  a total  of four tests were run on each pipe.  Two tests were run
for each of  base  sewage flows  of 10 and 30 gpm for the  12  in. sewer and
10 and 50 gpm for the 18 in. sewer.

A total of six tests were run on each pipe when the  two test sewers were
at slopes of 0.  004 (18 in.) and 0. 006 (12 in.  ). Three tests were  run for
each of the  sewage base flows  of 10 and 30 gpm for the  12  in. sewer and
10 and 50 gpm for the 18 in. sewer.

Two tests were run on the 12 in.  sewer at a slope of 0. 008.  The base
sewage flows used were 10 and 30 gpm.

Clean-Water Flush Tests

The clean-water  flush tests were  run to determine  the relative influence
of pipe diameter, pipe slope,  sewage base  flow,  pipe  length, flush vol-
ume,  and flush rate on the ability to clean sewers hydraulically.   These
tests were all  operated as described in the basic  operation previously,
using clean water as the flush  liquid.

A total of 72 tests were run on each sewer.   At the minimum slope values
of 0. 001 for the 18 in.  sewer and 0. 002 for  the 12  in.  sewer, a total of
45 tests were run. During these tests,  the  cleansing of the 12 in.  sewer
was related to  flush volumes of 300, 600, and 900 gal. , each of which
were combined with three different  flush rates ranging from 300  to
2, 000 gpm.  The effective cleansing  of each of these combinations of
flush rate and flush volume was evaluated at base sewage flows of 10, 20,
and 30 gpm. The 18 in. sewer was  tested in the same manner, except
that the flush rates ranged from 200 to 3, 000 gpm and the sewage base
flows  tested were 10,  30, and  50 gpm.

                                   27

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 The remaining 27 tests were run at slopes greater than the minimum.
 Twenty-three tests were run on both pipes, 12 at slopes of 0. 002 for
 the 18 in.  sewer and 0. 004 for the 12 in.  sewer and  11 at slopes of
 0. 004 for the 18 in. sewer and 0. 006 for the 12-in. sewer.   Four tests
 were run at a slope of 0. 008 on the 12 in. sewer only, as a steep-slope
 check of the  empirical relationships developed from the results of the
 tests run at the lower slopes.   In all of  these tests, the relative  cleans-
 ing of flush waves generated by flush volumes of 300 and 900 gal. each
 released at a high and a low flush rate (200 to 3, 000 gpm) were evaluated
 with sewage base flow of 10 and 30 gpm in the 12 in. sewer and 10 and
 50 gpm in the 18 in.  sewer.

 Sewage-Flush Correlation Tests

 The purpose of this  group of tests was  to determine if using sewage in
 place of clean water  affected significantly the cleansing ability of vari-
 ous flush waves and if so, to empirically define  the effect.  In general,
 the operation of these tests was the same as that used in the clean water
 tests  previously described, with the only difference being that strained
 sewage,  with known solids  content was used as the flush liquid instead of
 clean water.  All of these tests were run at slopes of 0. 002 and 0.  004
 for the 18  in. and 12 in.   sewers, respectively.

 The sewage used as the flush liquid was strained because the sewage
 used in actual practice will need to be strained to allow reliable handling
 by passing raw sewage through a 1/4 in. mesh screen.  The strained
 sewage was collected in one of the cone-bottomed collection tanks,
 where it was mixed and sampled for laboratory  analysis.  The mixed
 sewage was then pumped  to the primary or upstream flush tank and was
 used in the tests in the same manner as the clean water previously used.

 A total of eleven tests were run during this phase of the experimentation.
 This number is higher than was originally anticipated.  The increase re-
 sulted from the fact that the results from the first few tests indicated a
 decrease in the efficiency of the cleansing processes when sewage was
 used for flushing as opposed to when clean water was used.  Therefore,
 extra tests were  run to establish the relative magnitude of the
difference.

Flush Wave Sequencing Tests

 The purpose  of this group of tests was to determine the effect that the
time-sequencing of multiple flush waves has on  the efficiency of the
flushing operation.   The  general operation of these tests followed the
basic operation procedures outlined previously with one exception.
                                  28

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Instead of making one flush release at the upstream end of the sewers,
as done in previous testing,  up to three separate releases were  made
from three different locations  along the test sewers and the sequential
ordering and timing of these releases were varied.

A total of 10 tests were run on each sewer.  All of these tests were run
at slopes of 0. 002 and 0. 004 and sewage base flows of 50 gpm and 10 gpm
for the 18 in.  and 12 in. sewers,  respectively.  The first six tests were
run by placing 300 gal. of clean water in each of the three flush  tanks
(one at the upstream end and the other two at approximately 260 ft inter-
vals downstream) and varying  the rate and the relative sequence of re-
lease.  Two tests, one using a low rate of release (less than 1, 000 gpm)
and one using a  higher rate of  release (greater  than 1, 000  gpm)  were run
at each of the following three timing sequences:

1.   The flush volumes were released independently beginning with the
     flush tank nearest the downstream end of the  sewer (Tank Number 3)
     and were timed so that each of the three flush waves generated
     passed through the sewers independently.

2.   The flush release at the upstream end of the sewer  (Flush Tank
     Number  1) was made first.  The flush release at  the next down-
     stream flush tank (Tank Number 2) was then released when the max-
     imum depth of the flush wave generated by  the first release  was
     observed at this location.  Then the third release was  made from
     the flush tank located  nearest the downstream end of the sewer
     (Tank Number 3) when the flush wave generated by the two previous
     releases was observed to  be at its maximum depth at this location.

3.   The release from the  upstream tank (Tank  Number  1) was made first
     and the wave allowed to pass  completely through the sewers.  Then
     the other two releases were made in the same manner beginning
    with the next downstream  tank (Tank Number 2).

The four remaining tests were all run using the same timing sequence.
Each release was made when the flush wave generated upstream reached
its maximum depth at the respective induction point.  In one of the tests,
an average release rate of 1,450  gpm was used to release  900 gal. of
flush liquid from the upstream flush tank (Tank Number 1)  and 300 gal.
from each of the other two tanks.   Three tests were run using only two
of the flush tanks.  Release rates ranging from 200 gpm to 1, 600 gpm
were used to release 600  gal.  of flush liquid from the upstream flush
tank (Tank Number 1) and  300  gal. from the downstream flush tank
(Tank Number 3).
                                  29

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Flow Obstruction Tests

This group of tests was designed to study the overall effect of various
flow obstructions on the efficiency of the flushing operation.  The flow
obstructions studied included manhole  channel covers,  service connec-
tions, pipe misalinements, and  slope discontinuities.

The effects  of manhole-channel covers and service connections were not
evaluated by means of tests specifically designed for this purpose.   In-
stead, the effects of these discontinuities were qualitatively estimated
based on the observed flow characteristics of the various flush waves
that were generated and tested during the entire testing program.

Pipe misalinements were simulated by inserting steel rings into the pipe
joints at various points along the length of each pipe.  The effect of these
discontinuities on the overall efficiency of the flushing  operation was
studied by duplicating several tests that were previously run with pipe
misalinements minimized.  A total of five tests were run on each sewer,
all of which were run at slopes of 0. 002 and 0. 004 and  sewage base flows
of 50 gpm and 10 gpm for the 18  in. and 12 in. sewers, respectively.
In all of the tests, three simulated misalinements were placed at approxi-
mately  260  ft intervals in the 18 in.  sewer and six at approximately
130 ft intervals  were placed  in the  12 in.  sewer, with the first being lo-
cated near the upstream end of each sewer. Four of the tests were  run
with the steel rings extending 1/2 in.  above the invert of the pipes
and the remaining test was run with the steel rings extending 1 in.
above the inverts.  Flush volumes  of 300 and 900 gal. were each com-
bined with flush rates ranging from 200 gpm to 3, 000 gpm and were  tested
in each sewer.

A total  of three  tests were run to study the effect of grade misalinements
on the flushing operating efficiency.  All of these tests  were run at slopes
of 0. 002 and 0. 004 and sewage base flows of 50 gpm and 10 gpm for  the
18 in.  sewer and 12 in. sewer,  respectively.  Forty-three  grade discon-
tinuities were created at approximately 18 ft intervals  in each sewer, by
placing wedges under a given pipe joint to raise the inverts a specified
distance above true grade.  One  test was run on each sewer with the mis-
alinements one-half in. above grade and two tests were run with the  mis-
alinements one in. above grade.  Flush waves were  generated by combin-
ing flush volumes of 300 gal.  and 900 gal. with flush rates that were
previously used in the testing done with grade discontinuities minimized.
                                  30

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Inlet Configuration Effects

The purpose of this portion of the investigation was to study the effect of
changes in the configuration (size and shape) of the flush induction inlet
on the flushing operation.  There were no tests run specifically to evalu-
ate this influence.  The evaluation was made based on the observed flow
patterns of the flush waves generated in the rest of the experimental
testing.

Solids Buildup Tests

The purpose of this group of tests was to establish the growth of the
solids deposits expected to occur in small  sewers as a function of time.
This was accomplished by allowing domestic sewage to run through the
two test sewers for various lengths of time and determining the corres-
ponding quantity of solids deposited.

Three separate tests were run during this  investigation.  All three  tests
were run at slopes of 0. 002 and  0. 004 for the 18 in.  and 12 in.  sewers,
respectively.  The sewage flows used were continuously varied by the
influent controller which was programmed by a cam to vary the set point
and simulate the daily flow patterns normally found to occur in  lateral
sewers during dry weather tests (1),  (3),  (4), (5). The average 24 hr. flow
rates selected for these tests were 6  gpm for the 12 in.  sewer and
12 gpm for the 18 in. sewer.  These flows were derived based  on the
following assumptions:

1.   The 800 ft of 12  in. sewer was assumed to be an upstream lateral
     section directly  serving 25 single-family dwellings.

2.   The 800 ft of 18  in. sewer was assumed to be an intermediate lateral
     section directly  serving 25 single-family dwellings and carrying the
    flow from an upstream section serving 25 single-family dwellings.

3.   The single-family dwellings were assumed to contribute an average
    flow of approximately 350 gal. per day, based on an average occu-
    pancy of 3. 5 persons per dwelling and an average per capita  dis-
    charge  of 100 gal. per capita per day.

4.  The flows in the  sewers were assumed to be dry weather flows and
    therefore totally the  result of the domestic wastes generated.

Figure 8 shows the typical 24  hr. hydrograph of the flow through the two
sewers as used during all of the tests (1),  (3), (4), (5).  During the first
test,  the sewage was allowed to  flow through each sewer for a duration

                                  31

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            30- -
SEWAGE FLOW
  RATE (gpm)
               0       2
                                                                                     NOTE: The flow was varied linearly
                                                                                     between the points shown.
                                                 8        10
                                                                  12        14

                                                                 TIME (hours)
                                                                                    16       18       20       22       24
    Figure 8    SEWAGE FLOW RATE HYDROGRAPHS USED  IN  SOLIDS BUILDUP  TESTS

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of approximately 42 hours, alter which it was shut off.  The quantity of
deposited solids was then determined by completely cleaning each sewer,
using the storm simulation operation in the manner previously described.
Then the sewage flow was again started and the operation repeated for
durations of approximately 94 hours and 188 hours.

Inflatable Dam Evaluation

The purpose of  this group of tests  was to study the operational feasibility
of an in-line inflatable  dam as a means of storing and releasing sewage
to flush downstream sections.  The dam used was made of neoprene-
coated fabric and was patterned after the Firestone Fabridam.  The dam
•was attached to the invert of an  18 in. O. D.  stainless steel tube,  as
shown in Figure 9.  The  steel tube was then inserted into the  18-in.
sewer,  approximately 260 ft from  the upstream end.

The testing done using  the dam was quite brief.   The tests consisted pri-
marily of collecting various volumes of sewage in the sewer behind the
dam and then observing  the characteristics of flush wave produced.
Also the solids  deposits at several points above  and below the dam were
visually examined  before and after the dam was  deflated.
                  Figure 9   INFLATABLE DAM
                                  33

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FIELD AND LABORATORY PROCEDURES

The field data taken in all of the tests were recorded on the field
sheets shown in Appendix B.  The first form is the form used to rec
the flow  and volume data pertaining to each of the samples taken
the tests.  The  second form is  the form on which the observed c
istics of the solids deposits present at various points along the leng
each  sewer were recorded before and after the flush release.  This
was also used to record the measured depth of the sewage base flow an
flush wave at various positions along the sewers.

All of the samples taken during the course of the project were analyzed
in the laboratory for Total Suspended Solids. Volatile Suspended Solids,
and Total Organic Carbon. All of these analyses were  conducted in
accordance with commonly accepted laboratory procedures and techni-
ques.  The laboratory procedures  used are outlined in Appendix B.
Also, Appendix B includes a summary of the results obtained in a study
performed by FMC's Central Engineering Laboratories, which corre-
lates  the Total Organic Carbon concentration of the sewage used in the
tests, to the 5-day BOD concentration.

DATA ANALYSIS

The experimental data taken in the field were combined with the results
from the laboratory analyses,  by means of a series of calculations, to
determine the cleansing efficiency of the various flush waves tested.

A Suspended Solids (SS),  a Volatile Suspended Solids (VSS), and  a Total
Organic  Carbon (TOC) cleansing efficiency were determined for each
sewer in each test.  However, each of these  parameters was determined
in the same manner and for the remainder of this  section the term "solids"
will represent all three.

Solids Distribution Test

Before the efficiency of  the various flush wave could be evaluated, the
relative  distribution of solids deposits had to be known.  The data from
the Solids Distribution Tests were used to predict the distribution of
solids along each sewer, as deposited by each of the various base sewage
flows used in the tests at each of the slopes  tested.  The following com-
putational steps were  used to make the predictions for each test sewer.

1.  The  quantity of solids deposited in each of the four sections  of sewer
    (Sn.) was computed as follows:

                         S   = 8. 34 x 10" Ci Vi,                     (2)
                         Di

                                   34

-------
    where:

       8. 34 x  10"   is the product of the conversion of Vi from gal. to
                    Ib and the conversion of Ci from ppm to Ib per Ib

       S            is the total quantity of  solids deposited in section
       Ci           is the concentration of solids in the sample taken
                    of the discharge from the sewer when section i was
                    being cleaned (mg/1),  and

       Vi           is the total volume of  discharge collected when
                    section i was being cleaned (gal)

2.   The fractional contribution of each section (Pi) to the total solids
     deposited in the total length of sewer was determined as follows:
                                   =
    where P. is dimensionless .
             i

Clean-Water Flush Tests

The data taken during the Clean-Water Flush Tests were combined with
the results from the Solids Distribution Test and the  average cleansing
efficiency of each section of sewer as well as that for the entire pipe
length was determined using the following computational steps:

1.   The solids removed from the entire pipe length by the flush wave
         ) was determined  using the following equation:

                       S     = 8. 34 x 10~6 C  V  ,                  (4)
    where:
       S_   is in Ibs,
        FT
                                 35

-------
        C    is the concentration of solids in the sample taken of the
             discharge from the sewer following the flush (mg/1), and

        V    is the total volume  of discharge collected in the collection
             tank (gal. )

2.   The total quantity of solids remaining in each of the sections of pipe
     (Sp^j) was determined in the same manner that Spj was calculated
     previously.

3.   The total pounds of solids deposited in the sewer during the solids
     buildup  period (S^-p) was determined by taking the  summation of
     the solids remaining in each section of pipe
     'i = 4    \
          S-,. | and adding it to the solids removed from the sewer by the
              /
             /
     flushing wave (Sp ).


4.   The total pounds of solids deposited by the sewage base flow in each
     of the sections of pipe was estimated using the following relationship:


                             SDi = Pi SD
5.  The average cleansing efficiency of the flush wave in each section of
    pipe (Cj) was determined as follows:
                        CE. =           x 100%
                                  Di

6.   The average cleansing efficiency of the flush wave (CE) was deter-
    mined for the combined pipe sections in the following manner:

                                (S_ - Sn.)
                                 Di    Ri'    ,  „,
                                 T^ - *  10°*                  (7)
                                L =
                                 36

-------
    Where  CE .

       is the average cleansing efficiency over the length of pipe,
       L =  AL^+"ALn, in percent (ALI is the length of the first up-
       stream section of pipe in feet and n  is the number of pipe sec-
       tions included).

Sewage-Flush Correlation Tests

The data from the Sewage-Flush Correlation Tests were handled in the
same manner as that from the Clean-Water  Flush Tests,  except that the
calculation used to determine the total quantity of solids removed by  the
flush wave (SFT)  had to be corrected to account for the solids added to
the system by the sewage used for the flush. To accomplish this correc-
tion, the following relationship was used:

                 S    =8.34 x 1(T6/C  V   -C   V  \            (8)
                  FT               \ F   F    Fo  Fo)

    Where

       CF   is the concentration of solids in the sewage used for the
          o
             flush (mg/1) and
       VJT   is the volume of sewage used for the flush (gal.).


Miscellaneous Other  Tests

The data taken during the Solids Buildup Tests were handled in the same
manner as the data taken during the Solids Distribution Tests.  The data
taken in all of the other tests were analyzed in the same fashion as that
described for the Clean-Water Flush Tests.
                                  37

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                            SECTION VI

                            DISCUSSION

TEST  RESULTS

The experimental data from all of the tests run during the  course of this
project were analyzed using the computational procedures  previously
outlined in Section V.  The results from these various computations are
summarized in Appendix C of this report.

Solids Distribution Tests

The results of the Solids Distribution Tests were used in the analysis  of
the data from all of the Flushing Evaluation Tests to predict the relative
distribution of solids deposits along the sewers.  The figures given in
Table 7 (Appendix C) were obtained by averaging  the P^ values,  obtained
from  Equation 3, that were observed in two separate test runs on each
sewer at each of the given combinations of pipe slope and sewage flow rate.
In all cases, the P^ values that were averaged to  obtain P^  were within
5 percent of each other.

Examination of the values  of P^ given in Table 7 (Appendix C) shows that
in nearly every  case  the heaviest deposition of suspended solids occurred
in the first 526 ft of pipe.  However, as the pipe  slopes (S0) and sewage
flows (Qg) were  increased, this  phenomenon  became progressively less
significant and the  solids were deposited more uniformly along the length
of the sewers.

The effect of slope and flow rate on the relative distribution of the sus-
pended solids deposits along the  length of both the 12  in. and  18  in.
sewer is demonstrated by the plot in Figure 10.   The solid line repre-
sents the  mean suspended  solids distribution along the length of the
sewers.   This mean distribution was determined  by taking the average
of the distributions that were observed for each of the pipe sections at
all of the  various combinations of pipe slope and  flow rate  (Table  7, Appen-
dix C).  The broken line shown above the mean line represents the relative
suspended solids distribution found to exist when  a slope of 0. 001 was com-
bined with a sewage flow of 10  gpm.  The  broken  line shown below the
mean line represents the experimentally determined suspended solids
distribution that  resulted when a 30 gpm sewage flow was combined with
a slope of 0. 008.  A visual comparison of the  three curves shown in
Figure 10 shows that the slope of the lower dashed line  is  much more
uniform than that of either of the other two lines, which indicates that a
more uniform distribution of solids along  the length of the  sewers

                                   39

-------
          1.0
          0.8 -
          0.6 ••
 FRACTION OF
 SOLIDS DEPOSITED
UPPER LIMIT CURVE,
(So x QB> = 0.010 gals
                                                  MEAN DISTRIBUTION CURVE
          0.4 • •
          0.2 •
                   100
                          200
           300     400     500
           PIPE LENGTH — FEET
                                                           700
                                                                  800
     Figure 10   RELATIVE EFFECT OF SLOPE AND FLOW RATE
                 ON THE DISTRIBUTION OF SOLIDS
                 IN THE TEST SEWERS

resulted at the higher values of slope and sewage flow rate.  Also,  the
relative shapes of the curves indicate that the uniformity of the distri-
bution of solids along the  sewer is a function of the product of the slope
and  sewage flow rate values.  The results given in Table 7 show that in
the tests where the product of slope  and  sewage flow rate was  less  than
approximately 0. 080 gpm (which is the arithmetic average of SoQj3 for
all the tests),  the  resulting distribution curves  typically fall above  the
mean curve.  In those tests where the product of slope and sewage  flow
rate was greater than the average value  of 0. 008 gpm,  the resulting
distribution curves typically fall below the mean curve.

The relative distribution of Volatile Suspended Solids and  Total Organic
Carbon along the length of each sewer changes with variations in slope
and  sewage flow in much the same manner as described above.  However,
the  VSS and  TOC results given  in  Table 7 (Appendix  C) show that
the  distribution  of these materials is consistently more uniform than
the  total solids distribution.   This  indicates that the  equalization
of the  total solids distribution as a function of Sn  and Qp,  can be
                                   40

-------
primarily attributed to the fact that the increased velocities,  resulting
from steeper slopes and higher sewage flows, cause the lighter organic
materials to be carried further along the sewer before they are
deposited.

Clean-Water Flush Tests

The results from the Clean-Water Flush Tests are given in Tables 8,
9, and 10 (Appendix C). Each of the Suspended Solids, Volatile Sus- •
pended Solids, and Total Organic Carbon cleansing efficiencies given in
Table 8 (Columns 2,  3, and 4,  respectively) are the average cleansing
efficiencies over the corresponding pipe lengths shown adjacent
(Column 5) and were determined using Equation 7 (Cg).  The wave
depths given in Tables 9 and 10 are the results of the measurements
made during each test. Each value represents the  maximum depth that
the flush wave reached at the given distances (Column 3) from the up-
stream end of each sewer.

Correlation of Suspended Solids Cleansing Efficiency.  The correlation
of the observed values of suspended solids  cleansing efficiency (Cgce)
to the six independent variables, pipe length (L),  flush volume (Vjr),
flush rate (Qjr), pipe slope (So), pipe diameter (D), and  sewage base
(Qg) was accomplished in two general steps.   In the first step,  several
groups of results were randomly selected and systematically plotted,  in
the manner shown in Figure  11, to establish the general relationship
between each of the  independent variables (Vp, Qp, L,  So, Q-Q, and D)
and the dependent variable
The curves in Figure  11 are typical of those found for all of the combi-
nations of results plotted.   Examination of these curves  shows that in
general the value of CggS  increases when the values of Qjr, Vp, So,
and D are increased and decreases when the values of L  and  Qg  are
increased.

In the second step of the analysis the correlation between CggS and the
independent variables  was evaluated mathematically by means of a
series of regression analysis.  The complete set of results were first
subjected to a stepwise regression analysis using a general multiple
correlation equation.  The  standard error of the estimate was minimized
by separately varying  the exponents of each of the  independent variables.
The  relationship which resulted from  the analysis  is given in Equation 9.
The  cumulative  reduction in the sum of squares was 0. 621 (or 228., 904)
and the standard error of the estimate was 12. 82.
                                   41

-------
    I00|
                                   800
                      FX QF(C.F.XC.FS.)
                                                                      QB=.022CFS
                                                                      QB=067CRS
                                                                      QB=. I I I CFS
                                                                   NOTE.
                                                                    S. = 000l
                                                                    D = I 5 FT,
0

1
0 1

2
I
i
F XCF5
                                                   CBJ     L    y   FT'
   100 +
                                                                  D-I.S FT
Figure 11    TYPICAL CORRELATION OF  THE INDEPENDENT
                       VARIABLES  TO  C^^
                                             ESS
                                      42

-------
        CESS =  - "9. 8 + 66. 7 (VF x QF)°' 1 + 5. 07 Q^0' 5
                                                                   (9)
                 + 312.6 L"°' 1 + 57.7 S°* 5  + 111. ID0'1,
                                        o
      where

         V    =  Flush Volume, cubic feet
          .b

         QT-,  =  Flush Rate, cubic feet  per  second
          J?

         Q    =  Sewage Base Flow Rate,  cubic feet per second

         L,    =  Pipe  length,  feet

         S    =  Pipe  Slope, percent

         D    =  Pipe  diameter, feet

The multiple correlation coefficient and  computed F(D.F.  =  5, 538)  for
the regression were 0.788 and 173.05,  respectively, indicating that a
correlation between C     and the set of independent variables does
exist.  The relative oraer in which the independent variables influence
the correlation between Equation 9 and the observed  results is indicated
by the order of their appearance in Equation 9, with  the product of  Vjr
and  Qjr  demonstrating the greatest influence.  The information given
in Table 18 of Appendix D gives a more complete statistical character-
ization of Equation 9 and indicates that the relationship is representa-
tive of a majority of the observed results.  Also, the figures given in
Table 18 for the  reduction of the variance in each step of the  regression,
show that all of the  independent variables significantly decrease the
variance and therefore need to be included in the analysis to obtain maxi-
mum correlation.

Because of the shape of the curves shown in Figure 11 and the exponents
of the independent variables in Equation  9, a logarithmic correlation of
the results was attempted.  The relative correlation of  all of the depend-
ent variables was found to be increased when each  was replaced by its
base  10 logarithm and the above multiple correlation regression re-
peated.  After trying various arrangements of the variables,  the  rela-
tionship given by Equation 10 was found to  give the  maximum correla-
tion.  The values of the standard error and the multiple correlation
coefficient were found to be 12. 13 and 0. 806  respectively,  indicating
that  the correlation of Equation 10 was significantly better than obtained
                                  43

-------
by Equation 9.  An attempt was made to increase the correlation of
Equation 10

                                 1.3Q0.9S1.4D1.8

CESS =  -13'70 + ^681og10  F     F6   °	x 10
                                    L    UB

by eliminating from the analysis some of the results, which were ob-
viously not consistent with the bulk of the observed values.  The results
from three tests (12 observations) were eliminated and as a result the
standard error  and multiple correlation coefficient values were de-
creased to 11. 34 and 0. 828, respectively.   However, the value of the
intercept and the regression coefficient did not change significantly,
indicating  that the basic equation had not changed.  Further elimination
of questionable  observed values from the analysis reduced  the  standard
error and  multiple correlation coefficient but did not significantly
change  the basic equation.

Based on the  above analyses,  the relationship  given by Equation 10 was
found to provide the best estimate of the observed suspended solids
cleansing efficiencies.  The relative correlation of Equation 10 is given
statistically in  Table  19 (Appendix D) and is shown graphically in
Figure 12.

Examination of  the plot given in Figure 12 shows that the estimate of
CESS that is provided by Equation 10 is quite acceptable for the  range
of Vp, Qp,  L,  S0,  QB»  and D values that were included in the experi-
mentation. However, when this equation is to be used for the purpose
of designing flush equipment for sewers with lengths, slopes, sewage
flows,  or  diameters,  which are not  within the  range  of values that were
tested during the experimental development of the equation, the relia-
bility of the estimate  may be reduced.

 Correlation of Volatile Suspended Solids Cleansing Efficiency.   The
volatile suspended solids cleansing efficiencies (CEVSS)  given in
 Table 8 (Appendix C)  were correlated directly to the log function in Equa-
tion  10.  This was done because time limitations did not  allow for a  complete
 analysis and because  the observed values of CEVSS  showed consist-
 ently the same  patterns of variation as those shown by the observed
                                  44

-------
Ul
                            100--
                            90--
                            80+
                            704
                            604
AVERAGE    50-•
CLEANSING
EFFICIENCY

CESS
(PERCENT)
          40--
                             30--
                             204
                             10--
                                                                                              EQUATION 10,

                                                                                              CESS = -13.70 +  24.68 LOG10 (H)
                                                                                           NOTE:  + ESTIMATED VALUES
                                                                                                 • OBSERVED VALUES
                                                                                           H =
                                                                                                                   x 10
                                      -H	1	1	1	1	1	1	h
                               0      0.5       1.0      1.5      2.0
                                                                       '2.5|     3.0

                                                                        LOG (H)
                                                                                                         H	1
                                                                                        3.5      4.0      4.5      5.0
               Figure  12    SUSPENDED SOLIDS CLEANSING  EFFICIENCY  CORRELATION

-------
values of CESS-  The relationship that was developed is given in
Equation 11.  Figure 13 shows
    CEVSS - - 0.34 + 21. 72 log10   F    *    ° - x 10     (")
                                        L    QB

graphically the correlation of Equation 11 to the observed results, and
the statistical characterization of the relationship is included in
Table 20  (Appendix D).   The plot in Figure  13 shows that Equation 11
correlates quite well with the majority of the observed values of
CEVSS-

Correlation of Total Organic Carbon Cleansing Efficiency.   The total
organic carbon cleansing efficiency values given in Table 8 were  cor-
related to the log function given in Equation 10 and the result is given
by Equation 12.  As can be seen by examining the plot given in
Figure  14 and the statistics given in Table 21 (Appendix D) (only a 0.  165
reduction in the sum  of the squares), the estimate provided by Equation 12
is not reliable.  There are two possible  reasons for  this poor correlation.
First,  time did not allow a complete correlation analysis to be made  on
the results  and therefore the equation form used (Equation 10) may not
be the  most representative.  Second,  the TOG data gathered during the
course  of the project was not as consistent as the other data due to
large variations in the quality of the discharges from several canneries
which discharge into the sewer which was used as the source of sewage
for the  tests.
CETOC  = 22' 36 +  10" 3°    10      T1.6nlz
                                    L    QB

Correlation of Flush Wave Depth.  The results from the wave depth
 measurements,  given in Tables 9 and 10 (Appendix C), were plotted against
 pipe length (L) for each test.  The resulting curves indicated that the flush
wave depths generally decreased with increased values of L  and S
 and increased  with values of Vp,  Qp, and D.  Also, the wave depths
 appeared to decrease as a function of the square  root of L.

 Using the above  general relationships for reference, an analysis was
 run on the complete set of results in  Tables 9 and 10.  The statistical
 results from this analysis indicated that there was good correlation with
 all  of the independent variables, except pipe diameter (D).   The
                                  46

-------
       100 4
        90-.
        60-
AVERAGE
CLEANSING
EFFICIENCY

CEVSS
(Percent)
50..
        40--
        30--
        20"
        10--
                                                                    NOTE: + ESTIMATED VALUES
                                                                         • OBSERVED VALUES
                                                                 L1.6Q 1.2
                                                                      B
                  0.5      1.0     1.5
                                         2.0      2.5
                                             LOG (H)
                                                3.0      3.5      4.0      4.5      5.0
      Figure  13     VOLATILE  SUSPENDED  SOLIDS  CLEANSING
                         EFFICIENCY  CORRELATION

-------
00
                                    100 +
                                    80
                                    70
                                    60i
                            AVERAGE  50
                            CLEANSING
                            EFFICIENCY

                            CETOC
                            (PERCENT)
                                    40
                                    30-
                                    20-
                                    10'
                                            EQUATION 12
                                                                                                      NOTE: + ESTIMATED VALUES
                                                                                                           • OBSERVED VALUED
                                                                                                   v 1..
                                             0.5
1.0      1.5      2.0      2.5      3TO     45
                           LOG (H)
                                                                                                     4.0      4.5      5.0
                                     Figure  14     TOTAL  ORGANIC  CARBON CLEANSING
                                                        EFFICIENCY  CORRELATION

-------
influence of pipe diameter was shown to be quite small.  In order to
verify this, the results in the two tables were analyzed separately and
the relationships developed are given by Equations 13a and 13b.
Equation 13a was generated using the results from the 12  in. sewer
(Table 9) and Equation 13b was developed  using  the results from the
18 in. sewer (Table 10). - The statistics associated with each of the
relationships are given in Tables 22 and 23 (Appendix D).  The  relative
correlation of Equations 13a and 13b is shown graphically  in Figures 15
and 16, respectively.  Examination of Figures 15 and 16 shows that the
two equations generated are quite similar and that each shows good
correlation with the majority of the observed values.  Although the
overall relationship appears to be curvilinear and the correlation
might possibly be improved further by a more extensive analysis of
the results, in the range  of interest in this study it is represented
quite well by the straight line relationship.

W_  = 8. 45 + 0. 0230 V_ + 0. 534 (3   - 0. 261 L°* 5 - 1. 0 S  +2. 36 Q_
  U                   T          £                    O         Jt3

                                                                 (13a)

W_  = 8. 84 + 0. 0189 V_ + 0. 408 Q_ - 0. 322 L°' 5 - 0. 215  S   +  7. 29 Qn
  D                   .b          -b                       o         .D

                                                                 (13b)

where "Wj-j is the maximum wave depth in inches.

Steep-Slope Equation Check.  All of the relationships that  were developed
in the above analyses  are  somewhat questionable with respect to their
ability to make  accurate predictions about flushing sewers where the
values of L, So, QJJJ, and D are not  in the  range of the values that were
tested during the experimental work in this project.  For  this reason,
four flush tests were run on the  12  in. sewer  at a slope of 0. 008 to
attempt to  check the ability of these empirical relationships  to make pre-
dictions about flushing sewers with  slopes steeper than those previously
tested.  The cleansing efficiency results from these four tests are given
in Table 11 (Appendix- C);  Also  shown in  Table  11 are the  .correspond-
ing values  of CESS' ^EVSS'  and ^ETOC>  that were predicted using
Equations 10, 11, and 12, respectively. Comparison of these observed
and estimated cleansing efficiencies shows that  Equations  10 (Cggg)
and 11 (Cjrvss) were quite accurate in their predictions.   However,
Equation 12 (^EXOC^ ^ad  a rnuc^1 poorer correlation with the observed
results,  as would be expected because of  its unreliable representation
of the original  experimental results.
                                  49

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                                                                         18-
                                                                         16 +
                                                                         14-
                                                                        •12-
NOTE:  + ESTIMATED VALUES
      • OBSERVED VALUES
                                                                       "10-
H = 0.023 V_  + 0.534 Q^ - 0.261 L""'  - 1.0 So + 2.36 Q
                                 -5       -4
                                 VALUE OF (H)
Figure  15    WAVE  DEPTH  CORRELATION  FOR  12-INCH SEWER

-------
18-
16-
14-
.. 12-
NOTE: + ESTIMATED VALUES
• OBSERVED VALUES
... 10-
H = 0.0189 VF + 0.408 Qp - 0.322 LU'b - 0.215 So + 7.29 QB
* * • *• *
^(BT^
' '•' .OH-*
x* *
EQUATION 13B . •. . yjp"1 • . - •
\ ''«**1**" "' •' ''
' \ ' " JJ*11*^" 	 " : •'

Y"j0*F •••'••• •••
. .. * •;• ;•. 'jp? '.?".— '. -*••••• . • .
itlW" •

'. '. ." ',-'.~ 'W^^V: •?' ~ " '
. . -^ -. •• •
I 1 | I I | 1 1 1 n
-9 -8 -7 -6 -5 -4 -3 -2 -1 C
VALUE OF (H)
-
-
	
j. ""
*"* *"'"

-^'"

•
• •



FLUSH WAVE
	 DEPTH
W_ INCHES


, 	 1 	 i 	 i
1 1 	 1
) 1 2

Figure 16   WAVE DEPTH CORRELATION FOR 18-INCH SEWER

-------
The wave depth measurements made during these tests are compared to
the values estimated by Equation  13a in Table 12 (Appendix C).   The
correlation between the estimated and observed results are very good
and indicates that Equation 13a is capable of giving quite reliable esti-
mates of the flush wave depths at this steeper slope value.

Sewage -Flush Correlation Tests

The results from these tests,  where sewage was used as the flush liq-
uid,  are given in Table 13 (Appendix C).  The cleansing efficiency val-
ues given in the table were determined using Equation 8 and were used
to calculate the change in cleansing efficiency that  resulted from using
sewage.   This was accomplished  using the following equation:

                       4CESS » CESS  - CESS '                   (U)

where CEgg was determined from Equation 10 for the given values of
VF,  QF,  L,  S0,  QB, and D and CESS' is the corresponding suspended
solids cleansing  efficiency observed during the  Sewage -Flush Tests.
 The resulting values of ACEgg are given in Table  13  and were subjected
 to a multiple correlation regression analysis.  The relationship given by
 Equation 15 was found  to give the best correlation.  The  statistical pa-
 rameters associated with

          ACESS =  14. 3 - 0. 14 VF - 0. 242 QF  + 0. 00711 L         (15)

 Equation 15 are given in Table 24 (Appendix D).  Figure 17 shows the
 relationship between the observed values of CEss'  and t^ie dean-water
 cleansing efficiency equation (Equation 10). Examination of the plot
 shows that in general the overall cleansing efficiency was reduced
 slightly by using sewage instead of clean water. Also  shown in Figure 17
 is the plot of Equation  16, which is representative  of Equation 10
 (CEgg) after being corrected by Equation  15 (ACEgg  for  flushing with
 sewage.  The statistical parameters associated with Equation 16 are
 given in Table 25 (Appendix D).  The standard error of the  estimate
 (10.94) and the correlation coefficient (0.763) indicate that Equation 16
 gives an adequate representation of the experimental values of
                                     1.6   ,
                                         QB
                                  52

-------
Ui
UJ
             100- -
          IO 80--
60-|-
          UJ

          u>
          r

          10
          z
          <
          UJ


          d
          UJ
           cc
           UJ

           < 20
         NOTE  o THE OBSERVED RESULTS FROM

                 THE SEWAGE-FLUSH TESTS
                                                                         ( EQUA. 16 , SEWAGE -FLUSH)

                                                                          ^= -13-7 f 24.68 UDG,0IK)

                                                                         ( EQUA. 10, CLEAN WATER -FLUSH )
                                                                                                       5.0
                    1.0      1.5      2.0       2.5      3.0      3.5       4.0      4.5
                                  Figure 17'   SEWAGE-FLUSH CORRELATION

-------
Flush Wave Sequencing Tests.  The results from these tests, where mul-
tiple flush waves were used to clean the test sewers, are summarized in
Table 15 (Appendix C).  The observed values of cleansing efficiency given
in the table  are the values of Cjr;gg that were determined for the total
length of the sewers.  The  equivalent volume of flush (Vp1) that is given
for each of the multiple flush combinations  is the weighted average vol-
ume for the total length of sewer and was determined as follows:

                                 i = 4
                          V = fti -  •                      (17)
                                  =
where V. is the total volume of flush water that passed through section i
in gallons and  L.  is  the length  of section i  in feet.

The values  of  CEgg  that were estimated for each'of the equivalent
single -flush volumes was determined by solving Equation 10, using the
corresponding average flush rate and the equivalent single -flush volume.
Comparison of the values of ^ESS that were observed during each of
the three different flush release sequences, indicates that the sequence
of release  of multiple flush waves is not very critical to the overall
cleansing operation,  as long as the upstream releases are made first.
When the flush waves were released separately beginning at the tank
nearest the downstream ends of the sewers,  the observed values of
^ESS were  consistently lower than those obtained using the other two
release sequences.   The difference between releasing at maximum wave
depth and releasing  after the  upstream wave has passed was found, as
shown by the close correlation  of the observed C^gg values in  each
case, to be insignificant.

The estimated Cggg values for the equivalent single -volume flushes
show fairly good correlation to the Cjrjgg values determined for the
various multiple flushes tested.  This indicates that in general the
efficiency of multiple flush release was not significantly different from
the efficiency of the equivalent  single -flush release,  at least in the rela-
tive short lengths of pipes used in these tests (800 ft).  In longer lengths
of pipe, where pipe  length becomes the primary influence on the cleans-
ing efficiency, the use  of multiple flush waves  may very possibly become
a very important consideration.
                                   54

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Flow Obstruction Tests

Three general types of flow obstructions were studied in this portion of
the investigation.  The data from the tests that were run were analyzed
using Equation 7 and the results are given in Table  14 of Appendix C.

Pipe-Joint Misalinement Tests

The suspended solids cleansing efficiencies determined during these
tests,  where steel rings were used to simulate pipe joint misalinements,
are given in Table 14.  Figure 18 shows the relative correlation of the
values of ^Egg observed during these tests to the values  of CES
were predicted,  for the corresponding values of Vjr, Qjr,  L,  S0
and D, using Equation 10.  As can be seen by examining Figure 18, the
simulated misalinements had a negligible effect on the overall cleansing
operation.   Also, there was no consistent difference demonstrated
between the results from the tests where 1/2  in. high rings were used
and the tests where 1  in. high rings were used.

Grade Misalinement Effects.  The  suspended solids efficiencies deter-
mined during these tests, where grade misalinements were simulated
by raising  several sections  of pipe  above true grade, are given in
Table  14.  Figure 19 shows that the values of ^>Egg observed during
these tests  correlate quite well with the  Cj^gg values predicted using
Equation 10, indicating that the grade misalinements had little effect on
the overall  cleansing operation. The only flush waves that were notice-
ably affected by the discontinuities  in the grade of the sewer were those
that were generated by very low flush volumes and flush rates.

Manhole-Channel Covers and Service Connection Effects.   The effect of
covering the channels in manholes was determined to be insignificant,
based  on the observed wave patterns  and the  results from the other flow
obstruction  tests.   Interference in the flow pattern of the flush wave
can only occur, as a result  of these covers, when the depth of the wave
is greater than one-half the diameter of  the pipe.  Consequently,  the
only flush waves that would be hydraulically affected by the installation
of these  covers are those generated by large flush volumes and rapid
rates of  release,  and these are the flush waves that were shown in the
flow obstruction tests previously described to be the least affected by
physical discontinuities.

The effect of service connections on the  overall efficiency of the cleans-
ing operation was also found to be  insignificant based on the same rea-
sons that were given above  for the insignificant effects of covering the
channels in manholes.
                                 55

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    '00
y-
u

uj   80

o
c
?   60
(l)o OBSERVED RESULTS FROM TESTS

     USING |2" SEWER

(2) O OBSERVED RESULTS FROM TESTS

     USING 18" SEWER
         w •*/->•'Q^n1-*
I -t)  M _ (  V* Of 3? D  A
W  "  I   i»Q'-z    )
                                                 EQUATION 10 (Car -13.7+24.68 LDG,/I )
1.5
                                          2P
                                     3.0
                                                   H )
3.5
                  45
                  Figure 18   PIPE  JOINTS MISALINEMENT EFFECTS

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  tu
'O
 UJ
 UJ
 i/i
     IOO--
80-
60-
 o   40..
 ID

 UJ
 g  20-
       0
            NOTE, (I) »  OBSERVED  RESULTS FROM TESTS
                       USING 12'SEWER
                  (2)0 OBSERVED  RESULTS FROM  TESTS
                       USING 18" SEWER
                  (31 H - ( VWD1' x
                              Q1   '
                                                                            O
                                                                  O
                                                                        EQUATION 10 ( CESS"'"3-7•»24.68036^)
                          1.0
                                     20      2.5

                                       LOG,e(H)
                                                       3.0
                                                                     3.5
4.0
4.5
5.0
                       Figure  19    GRADE jMISALINEMENT EFFECTS

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Inlet Configuration Effects

During the early stages of the investigation, the inlet configuration used
to induce the flush liquid into the sewer was considered to be one of the
primary factors affecting the relative efficiency of the flushing opera-
tion.  However, the flow patterns that were observed for the various
flush waves tested during this project show that these inlet effects, are
quite insignificant, except in limiting the rate of flush release.  The
volume of flush liquid and the rate at which this volume is added to the
sewer  are the important factors affecting the cleansing operation.
Directing the flow downstream in the sewer, by means of an elbow or
other device, would only affect the cleansing operation in the first few
feet of pipe.  Moreover, the effect in the first few feet of pipe would be
significant only for a very short time after the beginning of  the release,
because  the flush volumes and rates necessary  for realistic cleansing
are high enough that the sewer becomes  surcharged shortly after the
release is made.

Solids  Buildup Tests

The complete set of results from the three Solids Buildup   Tests  that were
conducted are  given in Table 16  (Appendix C).  These results were derived
from the experimental data in the manner described in Section V.

Analysis of the results given in Table 16 shows that a relatively high
percentage of the  solids deposited in the sewers consisted of organic or
volatile  material.  An average of 60. 7 percent (Standard Deviation
= * 5. 90) of the deposited  materials were volatile  solids and 19. 4 per-
cent (Standard  Deviation = ± 3. 0) was organic carbon.  These percent-
ages are quite  representative of those found in all the tests  and can be
used to estimate the proportions  of volatile solids and organic solids
based  on the total solids distributions and buildups that will be dis-
cussed in the remainder of this section.

The distribution of the solids deposits over the  length of the sewers is
shown graphically in Figure 20, for each of the sewage flow duration
times  tested.   Examination of the distribution curves in Figure 20 shows
that in all cases 77 to 90 percent of  the solids deposited were deposited
in the  first 520 ft of pipe.  In general, the longer  the  buildup  period the
higher the percentage of solids in the first portion of the sewers.  This
heavy  deposition of solids found to occur in the  upstream portion of the
sewers indicates that in lateral sewers where the sewage is added more
or less uniformly along the length of the pipe,  instead of to  the upstream
end as was done in these tests, the major portion of solids will probably
                                        58

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Ul
           o
           CL
           o
           LJ
              12 "
              10--
0
NOTES: u).FI6URES SHOWN ADJACENT TO
        CURVES ARE THE CORRESPONDING
        SEWAGE FLOW DURATION TIMES
      12).12"SEWER; L =782 FT-
                 S.=004
        18 SEWER; L =795 FT.
                 S. =002
                                200
                 300
400
500
600
700
800
                                           PIPE  LENGTH  (FEET)
                     Figure 20   RELATIVE DISTRIBUTION  OF SOLIDS DEPOSITS

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be deposited within a relatively short distance downstream of where they
are introduced to the sewer.

The build up of solids deposits in the test sewers,  as a function of time,
is shown by the curves in Figure 21.  The curves show that the total
quantity of solids deposited in the 12  in. sewer was approximately one-
half that deposited in the 18  in. sewer after  188 hours.  However, the
deposition of solids in the 18 in. sewer reached a peak after approxi-
mately 120 hours, whereas the deposition of solids in the  12 in. sewer
had not reached a maximum even after  188 hours.  These two facts,
combined with the fact that the sewage flow rate in the smaller sewer
was approximately one-half  that in the larger sewer,  indicate that the
difference in total quantity of material deposited in the two sewers may
well be the result of the difference in the total quantities of solids that
passed through the two sewers, rather than purely a hydraulic
phenomenon.

The quality of  the sewage that was supplied to the sewers  during these
tests  should be considered when evaluating the total quantities of solids
deposited in the  sewers.  The suspended solids  concentration  (SS) of the
influent sewage varied from a high of approximately  150 mg/1 to a low
of 120 mg/1, with approximately 90 percent of the composite samples
taken having concentrations  within ± 10 mg/1 of  an average of  133 mg/1.
The volatile suspended solids  concentrations (VSS) varied from approxi-
mately 94 mg/1  to 114 mg/1 with the majority of the composite samples
taken having concentrations  within ± 5 mg/1 of the average of 102 mg/1.
The total organic carbon concentration (TOG) varied over a wider range
of approximately 94 mg/1 to 148 mg/1,  with only about 50 percent of the
composite samples taken having concentrations within ±20 mg/1 of the
average of 112 mg/1.

The figures given above for  the solids content of the influent sewage are
not as high as  those that are sometimes found for domestic sewage,  and
therefore should be considered when evaluating  the magnitude of the
solids deposits.  However, the quality of the sewage does not  seriously
alter the  relative effect of time.  Although much more extensive testing
would be  required before absolute  relationships could be developed,  the
test results given in Figure  21 show that more than three  times as many
solids were deposited in the sewers after 5  days as were deposited
after 1 day.  This is definitely a significant increase in pollutional
material  and deserves serious consideration.
                                   60

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to
o
z
3
o
Q-
    12  -
10--
NOTE;  TOTAL SOLIDS DEPOSITED AN.D THE

      TOTAL LENGTH OF THE TWO SEWERS

      (LENGTH OF 18* SEWER =795 FT.,
       LENGTH OF 12" SEWER -782 FT. )
                                                                S.S.- 18 SEWER
                                                               S.S. -12  SEWER


                                                               VSS-12" SEWER
              20
                                                                                   200
                                          TIME  (HOURS)
                   Figure  21    TIME SERIES BUILDUP OF SOLIDS

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Inflatable Dam Evaluation

The inflatable dam (see Figure 9) was installed in the 18  in. test sewer
and its general operation observed.  The dam was inflated to several
heights,  ranging from 4 in. to 16 in. , and the resulting flush wave ob-
served.  During these operations two major problems were found with
this method of storing and releasing flush liquid.  First,  the solids de-
posits above the dam appeared to be much heavier than experienced dur-
ing unobstructed sewage flows and the release of the stored sewage did
not appear to decrease the deposits appreciably.  The second problem
encountered was with the mechanical design of the dam, in that it would
not deflate rapidly enough to get  the full benefit out of the volume of sew-
age stored behind it.   The occurrence of these problems was the pri-
mary motivation for the proposed changes in the dam design which are
discussed later in this section.

In spite of the above problems, discharge rates  of up to 1,000 gpm were
attained.  Also, the solids deposited downstream of the dam appreared
to be  significantly decreased by the release of the sewage stored behind
the dam.

SUMMARY OF RESULTS

The results of the tests run during the course of this project are quite
comprehensive, but definitely not all conclusive.  The reliability of the
relationships that were developed from the experimental results are ""
limited not only by the statistical variations  in the results, but more
important they are limited by the range  of conditions included in the test-
ing program.  The statistical variations in the experimental results do
not cause as great a problem as  do the physical limitations of the testing
program, because their effects are predictable,  at least to a degree.
The most serious limitation on the general equations that were developed
is a result of the fact that only two diameters of pipe were used in the
tests.  This makes the reliability of making  predictions about sewers
with diameters significantly different from those tested somewhat ques-
tionable.  However, since the effect of diameter was found to be
relatively small in relationship to the effect of flush volume and flush
rate and the effect of diameter on the relationships generated for the
12 in. and 18 in. sewers were  quite small,  the predictions provided
by the general equations for sewers with diameters close to those
tested (8 in. to 24 in.) will quite  probably be within the  range of  stand-
ard error that was determined for each  of the relationships.
                                   62

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Using sewage instead of clean water for flushing was found to cause a
general, minor decrease in the efficiency of the cleansing operation.
As shown in Figure 1 7,  the effect is relatively small and is probably
the result of the redeposition of solids by the trailing edge  of the flush
wave.   This conclusion was made based on the fact that when clean water
was us^ed for flushing, the first portion of the wave carried nearly all of
the resuspended solids and the trailing low-velocity portion of the wave
was essentially clean water.   When sewage was used for flushing the
trailing, low-velocity portion of the wave contained relatively high con-
centrations of solids (equal at least to the concentration of  solids in the
strained sewage that was used for flushing) and significant  quantities of
these solids were redeposited along the length of the sewers.

The effects of the flow obstructions tested were found to be insignificant
in the range of flush volumes and flush rates that would normally be
expected to be used in actual practice.  Also,  since the flow obstructions
that would be encountered in existing sewers are almost impossible to
locate and even more difficult to  relate to the simulated obstructions
tested,  a relationship to correct for these effects would not be very
realistic.

The effects of flush wave sequencing were found to be insignificant as
long as  the  flush releases were made progressively from the upstream
end of the sewer.  Also,  the cleansing efficiencies obtained by using
various combinations of flush waves were found to be quite similar to
those obtained using single flushes  of equivalent volumes and similar
release rates.   However,  both of these hypotheses are  based on the
limited  findings from tests run on relatively short sewers and therefore
further  testing is required to give a complete picture of the relative im-
portance of these two factors on the overall performance of a complete
flushing system.

The inflatable dam was found to have some fundamental problems asso-
ciated with  its use for flushing sewers.  However, the  in-line dam is
the easiest  and  least expensive, of all the flushing devices  investigated,
to construct, install, operate, and  maintain.   This combined with the
fact that these dams could easily be used to reduce the quantity  of storm
water overflows and equalize the hydraulic loadings on treatment facil-
ities, makes further investigation of their capabilities  quite desirable.

The TOG results given can be used to estimate the equivalent 5-day BOD
of the deposited solids,  by using  the correlation relationship described
in Appendix B.  The discussion in Appendix B  shows that the sewage used
in the tests consistently had BOD5  concentrations of 1. 8 times the  TOC
concentration.

                                  63

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MATHEMATICAL MODEL DEVELOPMENT

Need for Mathematical Model

In a typical combined sewer installation a large number of periodic flush
stations will be required to periodically remove the solids that are set-
tled in the sewers.   The efficiency (i.e. ,  percent of solids removed from
the sewers) of the flush system depends on:

  •  System Parameters - Quantity of flush water and the rate of flush
                           discharge

  •  Physical Characteristics - Location,  length,  diameter and slope of
                                the sewers, and amount of flush water
                                available

  •  Load Characteristics  - Amount of solids settled in the sewers and
                            average base  flow  rate.

Given the physical and load characteristics of a combined sewer  instal-
lation,  there  exist a large number of alternative selections of the flush
system to achieve a specified cleansing efficiency.  The problem of
determining the best alternative is rather complex and calls for a mathe-
matical model.

Objective of Model

The objective of the model is  to select the best configuration for  locating
the flush stations and determine their capacities to achieve a specified
cleansing efficiency. The criterion for evaluation, depending on the
availability of cost  information, can be either of the following:

  •  Minimize the total  cost of the station's equipment and flush water
     required for operation of the flush stations.

  •  Minimize the quantity of flush water required.
                                   64

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The first approach is provided to be used when cost figures are avail-
able/whereas the second is provided so that the  model can be used to
determine the minimum water (or sewage) requirements even without
adequate cost information.

Scope of Model

The proposed model will be applicable to the "lateral" sections of a
combined sewer installation.  These are the sewers carrying the sew-
age from households,  commercial buildings, etc. to the "main"  sewers.
The scope of the model is limited mainly due to the limitations of the
design relationships.  There are,however, other important reasons,
e. g.:

  •  The "laterals" are the sewers where the majority of solids are
    deposited during the low flow periods. Hence,  cleansing of these
    sections will maintain the amount of solids  in the entire sewer sys-
    tem at a specified level, thus reducing the concentration of solids
    in the bypassed flows during the storm.

  •  The "mains" in the  sewer system can be treated independently.
    Given the load in  sections of the main sewer (from the direct
    connections and from the "laterals")  the same model can be applied
    for selecting and locating flush stations along the "mains" to
    achieve  a specified  cleansing efficiency.  However further experi-
    mental testing is  required before the design relationships developed
    in this project can be used for the larger diameter mains.

General Approach

A dynamic programming approach was used to determine optimality  of
each feasible combination of flush stations.  The model implicitly eval-
uates all possible alternatives to achieve  a specified efficiency within
the constraints imposed and selects the best one.   The  selection of the
best flushing system is based on values given to the following design
parameters.

1. Cleansing efficiency of the flush station

      •  as a function of flush volume and rate
      •  as a function of pipe size, length, and slope
      •  as a function of sewage  load.
                                65

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2.   Physical parameters
      •  potential locations along the "lateral"
      •  lengths, diameters,  and slopes of sewers between these
         locations
      •  engineering constraints at each location e. g. ,  size of flushing
         tank, amount of flush water available,  etc.
      •  average daily load in each sewer.

3.  Costs

      •  of flush station for given capacity
      •  of flush water at each location.

The design equations used in  the model are those  that were developed
during the experimental phase of this project.  The cleansing  efficiency
of each flush system evaluated is determined using the clean-water sus-
pended solids cleansing efficiency  (Cgss) equation (Equation  10) when
clean water is to be used as the flush medium and the sewage-flush sus-
pended solids (CESS') equation (Equation 16) when sewage is used.  A
complete description of the analytical procedures used in the model is
provided in Appendix F.  Also included in Appendix F is  a listing of the
computer program, accompanied by complete operational documentation
and examples.

Limitations

The use of the model is limited to the analysis of  single laterals with
physical characteristics (pipe diameters, pipe slopes,  etc.) similar to
those used in developing the design equations.  However,  the model is
designed so that it can readily be adapted to  virtually any sewer, by
experimental verification of the design relationships.

The model, as it now exists,  cannot determine the quantity of solids
expected to be deposited in a  given section of sewer.  This parameter
must be determined, by the user;  based on the sewage characteristics
and flow patterns of the given system, and supplied to the model as an
input parameter.

No specific provision is made in the model for variations in the relative
sequence of flush releases.   The overall cleansing efficiencies of the
selected combinations of flush stations are determined based on the
assumption that the flush releases are sequenced  so that the flushes will
be made progressively beginning from the upstream end  of the sewer.
                                  66

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ECONOMIC CONSIDERATIONS

A study of the materials deposited in storm water runoff areas in Tulsa,
Oklahoma, indicated that an average of approximately 0. 015 Ib of solids
were deposited daily per ft of street (2).  This is approximately 5 times
the quantity of solids found to be deposited in the test sewers during the
solids buildup tests.  However, the average BOD5 of the solids deposited
in the storm runoff areas  was only about 0.000415  Ib  per day per ft
of  street (2) as compared to an average BOD5 of the solids deposited in
the test sewers of approximately 0. 002 Ib per day per ft of sewer
(estimated using  the  TOC values determined in the testing and the TOC -
BOD5 correlation of  BOD5=!. 8 TOC given in Appendix B).  Comparison
of these figures indicates that the solids deposited in lateral sewers dur-
ing dry weather periods have a significant effect on the concentration of
pollutants in the  combined sewer overflows  resulting from  relatively
intense storms following extended dry weather periods.  Consequently,
if the quantity of solids deposited in the lateral sewer during dry weather
periods can be minimized,  a significant reduction in the pollution caused
by subsequent storm overflows from combined sewer will result.
The test results indicate that during the first 24 hours from 15 to 30
percent of the total quantity of suspended  solids that were carried
through the test sewers by the sewage flows  of 10 to 50 gpm were left
deposited in the 800 ft long sewers.   The solids that were deposited
were  on the average more than 60 percent volatile material.

The results from the Flushing Evaluation Test have shown that by using
reasonably small flush volumes,  the solids deposits in the lateral sew-
ers can be reduced by 60 to 75 percent each  day.  The results of the
Solids Buildup  Tests have  shown that the solids deposited at the end of
5 days is  at least three times the solids deposited at the end of one  day.
If we  continue with the assumption that the percentage removal is un-
affected by the amount or age of the solids deposited (within the limits
of the following example) the solids removed can be calculated  as indi-
cated in Table  1.  Compared to the solids deposited in 5 days with no
flushing this would result in net removals of:

            100(3  - . 66) -r  3 = 78% for 60%  daily removal

and

            100(3  - . 333)  -f 3 = 89% for 75% daily removal.
                                 67

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             Table  1   SOLIDS REMOVAL PREDICTIONS
                          (Daily Solids Deposited  = 1)
Day



1
2
3
4
5
1
2
3
4
5
Solids
Deposits
Prior to
Flushing
1
1.4
1.56
1. 62
1.65
1
1.25
1. 313
1. 328
1. 332
Percent
Remaining


40
40
40
40
40
25
25
25
25
25
Solids
Remaining
After
Flushing
.4
.56
.62
.65
.66
.25
.313
. 328
.332
. 333
Solids
With
No
Flushing
1
-
-
-
3
1
-
-
-
3
Net
Removal


60%
-
-
-
78%
75%
-
-
-
89%
From this example for a period of 5 days between storms it can be seen
that the improvement by sewer flushing is increased for longer periods
between storms.  For a specific installation the predicted net removal
for each possible period between storms would have to be weighted by
the probability of that period occurring, based on historical records,
and by the pollution load for that period to obtain the expected net re-
moval.  The expected net removal should then be comparable to per-
formance  obtained by other overflow pollution control  methods being
considered.  The correctness of the assumptions made and the  effect of
removal in laterals on the pollutional load at an overflow point should be
verified by a demonstration in a combined sewer system.

The mathematical model has been  set up to determine  the least cost of
performing periodic sewer flushing to achieve a given daily removal of
settled  material.  In  order to determine the cost for a specific  installa-
tion it would,  of course, be necessary to enter the particular installa-
tion and operating cost factors which apply to that local situation.  The
resulting minimum cost and the expected net removal  will provide the
basis for an economic comparison with other pollution control methods.

For the case of the laterals being considered for a possible demonstra-
tion in Detroit, two system layouts are  being considered to give either
61 percent daily removal  or 72 percent daily removal  depending on the
number of flush stations used.  Rough cost estimates were  made as
shown in Table 2.
                                 68

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              Table  2   ESTIMATED FLUSHING COSTS
Alternate
Number of flush stations per lateral
Area per lateral - acres
Daily solids removal - percent
Installed cost of fabric flush tanks
Cost of telemetry and controls
Monthly power cost
Monthly maintenance cost
Capital cost per acre
Monthly maintenance and power cost
per acre
1
2
9
61
$5, 556
2
4
9
72
$11,246
not estimated
$1.95
$100
$617
$11. 32
$4. 09
$200.
$1,250
$22.70
The cost for telemetering and remote control of the flushing system
would be dependent on the degree of automation needed as well as the
physical layout of the system in relation to the control center.
                                 69

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                             SECTION VII

     DESIGN AND TESTING OF A PROTOTYPE FLUSH STATION

There are numerous possible ways to mechanically acquire, store, and
release the  liquid volumes necessary to flush sewers.  The objective  of
this phase of the project was to investigate these various schemes  and
to select, design, construct, and test a promising arrangement.

DESIGN AND CONSTRUCTION

Several flush station designs were considered starting from the concepts
shown in Figure  22.  Other layouts were studied as reported in the
drawing list, Appendix E.  The design that was  selected to be the proto-
type tested in this project was selected because it appeared to be one  of
the most functional and promised to have reasonable construction costs
and low installation cost.

The prototype flush station was designed so that it can be easily in-
Stalled in and/or removed from almost any standard-type  manhole. The
complete station is built as a single unit for maximum ease in handling
and installation (see Figure 23).   The unit is held rigid by a 22  in.
diameter steel frame that supports the sewage supply and  control equip-
ment.  The  frame is surrounded by a polyurethane-coated nylon bag,
which is 4 ft in diameter and is designed to fit inside a  standard manhole
8 ft or more in depth.  The bag was designed to push against the walls of
the manhole when filled with liquid and then be completely collapsible
when emptied.   This allows the complete unit,  including the bag, to be
lifted into or out of a manhole with a minimum disassembly required.

The  sewage supply and control equipment consists of a  self-priming
pump, two electrically actuated four-way valves, a spring loaded
diaphragm-type actuator connected to a poppet-type dump valve, two
level control floats, and a 24 hour timer.   The equipment is arranged
so that the bag can be repeatedly  filled with sewage and rapidly emptied
in a  completely controlled fashion (see Figure 24A).

The bag is filled by positioning the four-way valves, one on  the suction
side and one on the discharge side of the supply pump,  so  that sewage is
pumped from a screened intake in the sewer to the bag  (Figure  24B).
During this  filling process,  the dump valve  is held closed by the spring
in the diaphram-type actuator.  When the level of sewage reaches the
desired maximum, the level control float located near the top of the bag
is activated and the  pump is turned off and both four-way valves are
rotated to the  hold positions as shown in Figure 24C,
                                  71

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PREFABRICATED FLUSH TANK
  FOR EXISTING MANHOLES
VACUUM FILL FLUSH TANK
   SURFACE FLUSH TANK
SEPARATE SUBSURFACE
     FLUSH TANK
  Figure  22   ALTERNATE FLUSHING STATION DESIGNS
                           72

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Fabric storage tank with the pump
and valves mounted underneath.
The discharge valve operator and bottom
bag support arms are shown above the
bottom support plate of the prototype flush
station with the fabric  tank removed.
                  Figure 23   PROTOTYPE FLUSH  STATION

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The bag remains full and the control valves remain in the hold position
until the timer rotates the valve 90 degrees to the next position,  shown
in Figure 24D, and restarts the pump.  The pump then pumps sewage
from the bag to the dump valve  actuator which opens the dump valve
and allows the sewage to be discharged back to the sewer.   When the
level of sewage in the bag reaches the desired minimum, the level con-
trol float located near the bottom of the bag is activated and causes the
pump to shut off and the four-way valves to rotate to the positions,
shown in Figure 24E, where the dump valve actuator is vented through
the intake screen and the dump valve is allowed to close.

When the  bag  is to be filled again,  the timer rotates the  two four-way
valves 90 degrees back to the fill position (Figure 24B) and starts the
pump.   The complete cycle is then repeated.

PROTOTYPE  TESTING

The operation of the prototype flush station was field  tested to deter-
mine its reliability and feasibility.  The various components of the
prototype were first tested individually and then their combined per-
formance was evaluated (Table  17, Appendix C).

After the  function of the various components had been verified, the pro-
totype  was assembled and was installed over a  manhole near the  efflu-
ent end of the  test sewers.  The sequence of operation previously des-
cribed, was run through several times  to determine  the average
discharge rate and  to verify the reliability of the supply  and  control
system.   Also the lifting mechanism,  designed  to allow the unit to be
lifted in and out of manholes, was operated several times to insure cor-
rect performance.

DISCUSSION

The prototype flush station (Figure 23) was tested mechanically and
found to be very functional and quite capable of performing the opera-
tions necessary to hydraulically flush sewers (see Table 17). The  sew-
age supply and release mechanisms were tested using sewage from the
test sewers and were found to provide reliable  operation.  The general
design of  the flush station was shown to be a promising and potentially
inexpensive method of holding and releasing sewage for the purpose of
flushing sewers.

Although the basic design of the prototype was found to be very func-
tional, there are several improvements that can be made.   Several
beneficial design changes became evident during the construction and
                                  74

-------
RESE
B






PUMP i v
INLET i >
VALVE
? I
GND •= P


TIMER
CONT/i
T 	 '
UPPEF
SWITC
V 	 	
0 	 .
LOWER
RVOIR HYDRAULIC SCHEMATIC
AG

. 	 I PC
/ T\
f DL
)PPET
'PE
MP
DUMP VALVE VALVE
ACTUATOR
X" ' _ / - T "VV PUMP DISCHARGE
J VALVE

1
* '• / /R\ r~x
U Jf \' • 1 >.
^ T r T ^ ' \ . \ PUMP
f - IQ)

A vLy
ELECTRICAL SCHEMATIC
©TIMER MOTOR
s~^ PUMP MOTOR
( Pi '
i (Fh RELAY#1
yn VlVTIME DELAY/-N RELAY
u — rTTii i
UU/ '
r.T9 n ,r WFT ,
\ K"l f~y- ^Q^o f^ ACTUATOR '
t 	 r-1 ^^ ~p-~-X"= = =~~
? FLOAT ~^W— 	 LTC ^ DISCHARGED
,H 1 	 | f—J ACTUATOR
n 1 1--- <)
I O 1 1 ^ '
c\
L£X- ' ^ RELAY #2
FLOAT SWITCH
1
*
Figure 24   PROTOTYPE FLUSH STATION CONTROL
            AND OPERATION
                          75

-------
   FILL
   POSITION
WATER LEVEL RISING
                                           DUMP
                                           POSITION
                                           (AFTER HOLD)
                                      F—{
                                     DUMP
                            M)       VALVE
                              PUMP   ACTUATOR
                              DISCHARGE
                              VALVE
                                PUMP
                              POPPET
                              TYPE
                              DUMP
                              VALVE
                                                       SEWER
                                                                                           WATER LEVEL FALLING
       DUMP
       VALVE
PUMP   ACTUATOR
DISCHARGE
VALVE
                                                                                                    PUMP
I POPPET
 TYPE
'DUMP
 VALVE
                                                                                                                           SEWER
HOLD POSITION
(AFTER FILL)
                                                                                                 D
                        WATER LEVEL AT TOP
                                          ACTUATOR
                                          VENT
                                          POSITION
                                          (AFTER DUMP)
                                      DUMP
                                      VALVE
                              PUMP    ACTUATOR
                              DISCHARGE
                              VALVE
                                 PUMP
                                                        POPPET
                                                        TYPE
                                                        DUMP
                                                        VALVE
                                                        SEWER
                                                                                           WATER LEVEL AT BOTTOM
                                                                               DUMP
                                                                     M)       VALVE
                                                                        PUMP   ACTUATOR
                                                                        DISCHARGE
                                                                        VALVE
                                                                                                   PUMP
                                                                                     —C
                         POPPET
                         TYPE
                         DUMP
                         VALVE
                         (IN
                         PROCESS
                         OF
                         CLOSING)
                                                                                                                           SEWER
                    Figure  24     PROTOTYPE FLUSH STATION  CONTROL
                                      AND  OPERATION  (CONTINUED)

-------
testing of the prototype.  These changes were incorporated into the
proposed improved design shown in Figure 25.  This design will allow
considerable simplification in the construction and installation of the
flush station and assembly of the piping.   Also the number and complex-
ity of the control circuits required has been greatly  decreased by this
design.

An improved design of the in-line type dam is shown in Figure 26.   This
design allows  the excess sewage to flow out under the dam, thus reduc-
ing the solids  buildup in the  sewer behind the dam.   Also the dam as-
sembly is arranged  so that the dam can rapidly be removed up from the
sewer by applying a vacuum,  thus  allowing the stored sewage to be  re-
leased quickly to develop maximum cleansing velocities.  This also
allows the dam to be pulled completely clear  of the sewer during storms
when the fabric  of the dam might be damaged.  Also the dam is proposed
to be installed in the center of a manhole which allows easy installation
and  maintenance of the  dam.  The overflow weirs that  are shown on
either side of the sewer immediately upstream of the dam provide the
necessary protection against  accidental flooding of the sewer upstream
of the dam.
                                 77

-------
-j
oo
                 DISCHARGE
                                        INTAKE HOSE-
                                                             TANK — SYNTHETIC
                                                             COATED NYLON
                                                             FABRIC           C

                                                              MANHOLE
                                                               PNEUMATIC
                                                               DIAPHRAGM
                                                               PUMP

                                                               PNEUMATIC
                                                               OPERATOR
                 VIEW B-B
                 SCALE-1/4
      SEE DETAIL A
                                                        \
18" SEWER PIPE
VIEW C-C
SCALE-1/4
                                               DETAIL C
                                               SCALE-1/4
       -COARSE CLEARANCE FIT
       -2"  STANDARD PIPE

       -SHOE
                                                           DETAIL A
                                                           SCALE-1/4
                                                                                          L
                          Figure 25   PROPOSED FABRIC BAG  FLUSH STATION

-------
 BOLT TO
 BOTTOM
 OF
 MANHOLE
DIAPHRAGM
ELASTOMER
COATED	
FABRIC
                         ^STREET
              LEVEL
                                   MANHOLE
                            HOSE TO PUMP
AIR
PRESSURE
        RIGID AIR CELL

       SEAL DIAPHRAGM
       TO RIGID AIR CELL
  DIAPHRAGM PULLED
  BY VACUUM OUT OF
  THE WAY INTO UPPER
i/PORTION OF RIGID
  AIR CELL

  BY-PASS WEIR
                                                             18" SEWER PIPE
                                 FLOW
      GATE IN INFLATED POSITION
                   GATE IN DEFLATED POSITION
         Figure 26   PROPOSED IN-LINE DAM FLUSH STATION

-------
                            SECTION VIII

         ARRANGEMENTS FOR FIELD DEMONSTRATION OF
      PERIODIC FLUSHING OF COMBINED SEWER LATERALS

Any pollution control technique must be demonstrated under practical
field conditions before it can be widely accepted and used.  The objec-
tive of this phase of the project was to expedite a demonstration
(Phase III) of the periodic  sewer flushing technique in an operating sewer
system.

SOLICITATIONS FOR DEMONSTRATION LOCATIONS

1968-69  Hammond, Indiana.  Worked with consulting engineers
Consoer, Townsend and Associates to get an expression of interest of
the Sanitary District of Hammond to explore the possibility of setting up
a demonstration.  Prepared two tentative  flushing system layouts and
demonstration plans for the Tapper Avenue  area.  The Sanitary District
expressed a preference for the Walnut Avenue area because relief sew-
ers had already been installed there.  Prepared tentative flushing sys-
tem layout for the Walnut Avenue area.  The Sanitary District of
Hammond finally ruled out the possibility  of a periodic flushing system
demonstration based on the work load in the sanitary district,  the fear
of legal action if any flooding were to occur, and the  cost to the district.

1969, Cleveland, Ohio.  Cleveland responded favorably to suggestions
for a  sewer flushing demonstration.  Information was supplied to the
consulting engineers Engineering Science, Inc. to serve as a basis for
including sewer flushing as one of several methods of storm water over-
flow pollution control to be demonstrated.   The area  for the sewer flush-
ing study was to be from West 102nd Street  to West lllth Street between
Clifton Boulevard and Baltic Road.  Part of the flushing water was to be
supplied from  storm water collected in a demonstration of local deten-
tion and  storage.

Cleveland had  taken no action on the proposal prepared for them by
Engineering Science because of the press  of more urgent matters.  Al-
though no time table can be given for action on the proposal, it is not
necessarily dead.

1969, San Francisco, California.  Requested Gene Kazmierczak, Chief
Engineer,  Engineering Science,  Inc. , Consulting Engineers,  Arcadia,
California, to  review possibilities of interest in a Sewer Flushing Dem-
onstration Grant Application with client, City Engineer, San Francisco,
                                  81

-------
in connection with Combined Sewer Demonstration Project concerning
Outfall Treatment.  Kazmierczak reported no interest.

1970, Alexandria, Virginia.  Reviewed possibility of a Sewer Flushing
Demonstration Project as a solution for minimizing Combined Sewer
Overflow pollution with Carl Rehe,  Greeley and Hansen; Chicago, Illi-
nois; consultants for Alexandria,  Virginia; re: Enforcement Proceed-
ings. Rehe reported interest would be  subject to study program find-
ings and doubted any significant pollution from storm overflows.

1970, Detroit,  Michigan.  Reviewed background information on periodic
flushing  of laterals with A. C. Davanzo and John W. Brown, Acting
Sanitary Engineer.  Their reaction was favorable with a particular in-
terest in using inflatable dams for in-line storage of sewage for flush-
ing.   They supplied  a sewer map  of a tentative demonstration location
for preliminary layout of a flushing system.  A commitment to use the
area for a demonstration was to be  contingent on details of the system.

The tentative flush system layout was made for an area bounded by
Fenkell Avenue,  Lamphere Avenue,  Midland Avenue, and Rockdale
Avenue.  Three parallel laterals will be used with identical slopes,
diameters and lengths.   One of the laterals will be used as a control
with no flushing.  Inflatable flush gates  will be installed for in-line
flushing  liquid storage in one  of the laterals.  The other lateral  will be
flushed from sewage stored in fabric flush tanks  inserted in the  existing
manholes similar to the prototype flush station developed under  this
contract.

The information on the proposed demonstration has not been in the
hands of the Detroit personnel long  enough for there to be a reply at the
time this report is being prepared.
                                  82

-------
                             SECTION IX

                       ACKNOWLEDGEMENTS

The two inflatable dams that were tested were supplied without charge
by Imbertson Engineering,  Los Angeles, California.

Consulting on the structural design of the test facility was provided by
the San Jose Office of Consoer, Townsend  and Associates.

Mr.  Milton Spiegel, FMC Corporation Staff Consultant,  was responsi-
ble for  much of the promotional and investigational work done  in the
negotiations for flushing demonstration sites.

Mr.  William Kannenberg and Mr.  Manner  Naik of the FMC Corporation
Management Information Systems group were primarily responsible for
development of the mathematical  model.

The equipment design, field testing, laboratory analysis, data reduction
and the report preparation were all accomplished through the efforts of
the Environmental Engineering Department of FMC  Corporation's Cen-
tral Engineering Laboratories, under the supervision of D. W. Monroe
and J. P. Pelmak and the direction of F.  F. Sako.

The support of the project by the  Environmental Protection Agency  and
the guidance and help provided by the Contract Officers, Messrs.
A. D. Beattie and L. L.  Weinbrenner and  by Messrs. G. A. Kirkpatrick
and W.  A. Rosenkranz is acknowledged with sincere appreciation.
                                   83

-------
                            SECTION X

                           REFERENCES

1.   Clark, John W. and Viessman, Warren, Jr. ,  Water Supply and
    Pollution Control, International Textbook Company, Scranton,
    Pennsylvania,  pp  166-218  (1965).

2.   Cleveland,  Jerry  G. ,  Ramsey, Ralph H. , and Walters, Paul R. ,
    "Storm Water Pollution from Urban Land Activity.- " Combined
    Sewer Overflow Abatement Technology, FWQA Report No.
    11024-06/70,  pp 1-55 (June 1970).

3.   Cohn,  Morris M. , Sewers for Growing America, Certain-teed
    Productions Corporation,  Ambler, Pennsylvania (1966).

4.   Design and  Construction of Sanitary and Storm Sewers, WPCF
    Manual No.  9, Water Pollution Control Federation, Washington,
    D. C.  (1970).

5.   Fair, Gordon M. , Geyer,  John C. , and Okun, Daniel A. , Water
    and Waste Engineering, Vol. 1,  Water Supply and Wastewater
    Removal, John Wiley & Sons,  Inc. , New York, N.  Y. ,  pp 5-1 to
    5-25 (1958).

6.   Ford,  Davis L. , "Total Organic Carbon as a Wastewater Param-
    eter" Public Works 99_, 89 (April 1968).

7.   Schaffer, R. B. ,  Van Hall,  C. E. ,  DcDermott,  G.  N. , Earth, D. ,
    Stenger, V. A. , Sebesta,  S. J. ,  and Griggs, S. H.  "Application
    of a Carbon Analyzer in Waste Treatment" J.  WPCF 37_,  1545
    (1965).
                                   85

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                             SECTION XI

                        GLOSSARY OF TERMS

Average Cleansing Efficiency - The percent of deposited solids
removed from a given length of sewer.

Deposited Solids - The quantity of suspended solids that settled out of
the sewage passing through the sewer  and is left deposited over the
given length of sewer.

Periodic Flushing  - Systematic induction of stored liquid into sewers at
relatively high rates of  release.

Suspended Solids - Particulate materials suspended in sewage.

Volatile Suspended Solids  - That portion of the suspended solids that is
organic in nature.

Total Organic Carbon - The total quantity of carbon present in the sus-
pended  solids as a result of the presence of organic materials.

5-Day BOD  - A measure of the oxygen required for the biochemical
degradation of organic material.

Average Flush Rate - The average rate at which the flush liquid is dis-
charged into the sewer.

Volume of Flush - The total volume of liquid added to the sewer by the
flush release.

Relative Solids Distribution - The distribution of deposited solids over
the length of the sewer.

Relative Correlation - A measure of the ability  of a general relationship
to predict the value of an experimental parameter.

Depth of Flush Wave - The maximum depth that a given flush wave
reaches a specified distance downstream of the  induction point.

Flush Wave - The unsteady flow condition resulting from the rapid in-
crease in the flow rate in an open channel or gravity sewer.
                                   87

-------
Dry Weather Flows - The flows in a combined sewer that result from
domestic  sewage discharges with no significant contribution by storm
water runoff.

Combined Storm Flow - The flows in a combined sewer that result from
the combination of domestic sewage discharges and storm water runoff.

Combined Sewer Overflows - The quantities of combined storm flow
that are discharged without treatment to receiving streams  and lakes.
                                 88

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                        SECTION XII



                        APPENDICES





                                                                Page



A.    Results from Shakedown Testing  	     91





B.    Field and Laboratory Procedures	     93





C.    Results from Flushing Evaluation Tests	    105





D.    Statistical Analysis of Design Equations	    147





E.    List of Design Drawings	    155





F.    Description of Mathematical Model	    159
                                89

-------
                        APPENDIX A

           RESULTS FROM SHAKEDOWN TESTING


Table 3   RESULTS FROM FRICTION COEFFICIENT TESTS

Pipe
Diameter

-D-
(in.)
18
18
18
12
12
12

Pipe
Slope

-S-
(ft/ft)
0. 001
0.001
0. 001
0. 002
0. 002
0. 002

Average
Discharge

-Q-
(gpm)
819
658
285
829
693
291

Average
Flow
Depth
-d-
(in. )
7.56
7. 20
4. 80
9. 00
8.40
5. 51

Average
Velocity

-V
(fps)
2. 58
2. 21
1. 63
2.91
2. 63
1. 89
Average
Mannings
Friction
Coefficient
-n-

0. 0088
0. 0100
0.0109
0.0104
0. 0113
0.0135
       Table 4   RESULTS FROM HYDRAULIC  MIXING
                 TEST USING SEWAGE
Volume of
Sewage
(eals. )

1200
2000
2800
2000
Mixing
Time
(min)

1. 2
2. 0
2. 8
4.0
Volumes
Displaced

1
1
1
2
Average Suspended
Solids Concentration
mg/liter
Before Mixing
178
163
180
130
After Mixing
187
159
171
138
   Pumping rates -were constant at approximately 1, 000 gpm.
                             91

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                  Table 5    RESULTS  FROM  HYDRAULIC  MIXING TESTS USING  FINE  SAND
Nl

Volume
of Water




(gal)
1200
2000
2800
1200
2000
2800
1200
2000
2800

Sand
Added




(Ib)
0. 50
0. 84
1. 17
2. 00
3.34
4. 66
6. 00
10.00
14.00

Actual
Concen-
tration
of Sand



(mg/liter)
50
50
50
200
200
200
600
600
600
(T)
0. 5 Volumes
Displaced
Mixing
Time


(min)
0.6
1. 0
1.4
0.6
1.0
1.4
0.6
1.0
1.4
Sand
Concen-
tration
in Sample
(mg/liter)
54. 2
40. 1
39.3
182
215
150
510
620
585
CD
1. 0 Volumes
Displaced
Mixing
Time


(min)
1.2
2. 0
2. 8
1. 2
2. 0
2.8
1.2
2. 0
2. 8
Sand
Concen-
tration
in Sample
(mg/liter)
50. 5
51. 0
49. 2
202
200
202
202
598
597
CD
2. 0 Volumes
Displaced
Mixing
Time


(min)
2.4
4.0
5.6
2.4
4.0
5.6
2.4
4. 0
5.6
Sand
Concen-
tration
in Sample
(mg/liter)
50. 2
49. 6
50. 8
200
198
199
201
603
597
               The pump rate was constant at 1, 000 gpm.

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                         APPENDIX B

            FIELD AND LABORATORY PROCEDURES
                SEWER FLUSHING EVALUATION
                   FIELD  SAMPLING RECORD
DATE:   2-18-70
                           PAGE 1  OF  1
INVESTIGATOR:
TEST NO.  46
L. N.
SLOPE: 18" PIPE

        12" PIPE
.001

. 002
Test Period Description
No. 1
Solids
Build up

Flush
Evalua-
tion




Storm
Simu -
lation
Tests



Sample
Numbers
Tank *
No. 1 ,
Tank
No. I
Tank
No. -S
s
Test
No. 1 4
Test
NO. : B
a
Tost
No. .1 s
11
Test
No- 4.o
Test
No. S
Test
No. t>
Test
No. ~
18" Pipe
12" Pipe
IS" Pipe
li" Pipe
IS" Pipe
li" P\p*
IS" Pipe
i:" Pipe
IS" Pipe
i;" i\pe
IS" Pipe
i:" Pipe
IS" Pipe
U" Pipe
IS" Pipe
12" Pipe
IS" Pipe
i: ' Pipe
IS" P\p«
U" Pipe
IS" Pipe
IS" Pipe
Time — PST
Begin




















End




















Average
Discharge
(gpm)
SO
10



















Average
Depth
of Flow
(in.)
:. i
l.i



















Average
Valocitv
(fps)




















Total
Elapse
Time
(min)
657
!•>. 5



















Total
Discharge
(gals. 1
iO.4^0
11"
IS"
1".'1S sees.
5'V15 sees.


24"
i4"
ic>"
^4"
\S"
Jo"
40"
40"






Length of Pipe
Downstream of
Flow Induction
Point (ft)


5psi «00
3 psi at Spsig QQO
«00 gals.
at 5 psvg

















-------
                SEWER FLUSHING EVALUATION
         FIELD HYDRAULIC  AND SOLIDS  DATA SHEET
DATE:   2-18-70
INVESTIGATOR:
L. N. & DEL.
Page   1  of  3

TEST No.  46
Inspec-
tion
Point
No.
1
2
3
4
5
6
7
8
Test
Pipe
18" Pipe
12" Pipe
18" Pipe
12" Pipe
18" Pipe
12" Pipe
18" Pipe
12" Pipe
18" Pipe
12" Pipe
18" Pipe
12" Pipe
18" Pipe
12" Pipe
18" Pipe
12" Pipe
Location of
Point With
Respect to
Downstr earn
End of Pipe
(ft)
3 - 4
3-4
10 11
10 11
15 16
15 - 16
21 - 22
21 - 22
41 42
41 - 42
52 - 53
52 - 53


Comments
(Approximate)
1/32" of solid buildup, flow 2"
1/32" of solid buildup, flow 1"
1/8" of solid buildup, flow 2-1/2"
1/16" of solid buildup, flow 1"
1/16" of solid buildup, flow 2-1/4"
1/32" of solid buildup, flow 2"
1/8" of solid buildup, flow 2"
1/16" of solid buildup, flow 1-1/4"
1/32" of solid buildup, flow 2"
1/32" of solid buildup, flow 1-1/4"
1/64" of solid buildup, flow 1"
1/64" of solid buildup, flow 1-1/2"


                               94

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                    LABORATORY PROCEDURES

I    TOTAL SUSPENDED SOLIDS ANALYSIS

     A.    Apparatus

          1.   Millipore filtering equipment
          2.   Whatman glass filter paper,  GF/C 4. 25 CMS
          3.   Pipets,  graduated cylinder

     B.    Procedure

          1.   Weigh a filter paper on the analytical balance and place
               it in position on the filtering apparatus.
          2.   Depending on the  type of sample, pipet or measure by
               graduated cylinder an appropriate size sample to the
               filter paper  and apply vacuum.
          3.   Rinse the measuring device and filter  funnel with dis-
               tilled water  and after the water has been extracted,
               remove  the filter paper and place it in drying oven for
               30 minutes at 103 to 105° C.
          4.   Cool the filter paper in a desiccator and reweigh.
          5.   Run a blank in the same manner using distilled water.

     C.    Calculation
                  „.    „      , , ,,        (A - B) + (C - D) x 1000
               mg/liter Suspended Matter  =	•	~=	
                                                      iii
          where
                  A = Weight of filter paper and dried  solids  _
                          B           ^ *                    Sample
                  B = Weight of filter paper only

                  C = Weight of filter paper only
                                                             Blank
                  D = Weight of filter paper dried

                  E = ml sample

II    VOLATILE SUSPENDED SOLIDS ANALYSIS

     A.    Apparatus

          1.   Muffle Furnace, 0 to 1100°C
                                  95

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    B.    Procedure

          1.  Place the dried filter paper from the total suspended
              solids analysis in an alundum crucible and place in
              muffle furnace.
          2.  Ignite the residue on the filter paper at 600  C for
              approximately 1 hr.
          3.  Cool the crucible and its substance in a desiccator and
              reweigh the filter paper only.
          4.  Run the blank from the total  suspended solids analysis
              in the  same manner.

    C.    Calculation
                                               (A - B)  - (C - D) x 1000
          mg/liter Volatile Suspended Matter = 	—	

          where
                 A = Weight of filter  paper and residue

                 B = Weight of filter  paper and residue after    amP e
                      ignition

                 C = Weight of filter  paper only
                                                             j Blank
                 D = Weight of filter  paper after ignition

                 E = ml sample

in  TOTAL ORGANIC CARBON ANALYSIS

    A.    Apparatus

          1.  Beckman IR-315 Carbonaceous Analyzer
          2.  Hamilton #705 N/LT Microsyringe,  50 Ml capacity
          3.  Waring blender

    B.    Reagents

          1.  Glacial acetic  acid:  ACS grade
          2.  Hydrochloric acid:  1+5

    C.    Standardization

          1.  Accurately weigh 1. 000 gm of glacial acetic acid into a
              1-liter volumetric flask and dilute to volume with CO2~
              free distilled water.   1  ml  = 1.0 mg of Acetic acid =
              0. 400  mg of C.
                                 96

-------
      2.   Prepare 5,  10,  15, 20, and 25 ml aliquots from stock
          solution and dilute to volume in 100 ml volumetric flasks.
          The above dilutions represent 20, 40, 60,  80, and 100
          mg/liter of  carbon respectively.
      3.   Starting with the highest concentrations, inject a 20  /*!
          sample and  adjust the instrument to that concentration
          by moving the gain control located on the front panel.
      4.   Continue to  inject samples from the same concentration
          and adjusting the gain control until successive results
          are obtained.
      5.   Proceed with the remainder of the standards.
      6.   Plot the average peak heights obtained against the stand-
          ard concentration on a graph.

D.    Procedure

      1.   Place a portion of the sample in a Waring blender and
          mix thoroughly for 2 minutes.
      2.   If sample is to be determined for total organic carbon
          (TOC),  add  a few drops of HC1 solution and remove CO^
          by bubbling  Helium through the  sample.
      3.   Prepare the necessary dilution  and inject a 20 M! sample
          and record the peak height.
      4.   Repeat paragraph 3 until  successive  results are obtained.
      5.   If sample is to be analyzed for Total Carbon  (TC), make
          the necessary dilutions and repeat steps 3 through 4.
      6.   Estimate the concentration in the sample by comparing
          the reading  with the standard curve.

          NOTE:  For additional information, refer to  instruction
          manual Beckman 61008.
                              97

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            BOD6 - TOG RELATIONSHIPS FOR CENTRAL-
       ENGINEERING LABORATORIES (GEL) WASTEWATERS

INTRODUCTION

During the testing of various types of activated sludge treatment at GEL
over a period of 18 months, concentrations of BOD5 and TOG were mea-
sured for many samples of sewage.  These accumulated results are the
basis for the correlations of BOD5 with TOG presented in the following
discussion.

GEL SEWAGE

In most wastes, the primary source  of BODg is the biological oxidation
of organic  carbonaceous material. For this  reason,  the BOD5  should be
directly  related to the waste's TOG.   As shown in Figure 27, there are
two straight line relationships between BOD5 and TOG.  For a TOG
below 300,  the BOD5 is equal to 1. 5  times the TOG; above a TOG of 300,
the BOD5 is equal to 1. 8  times the TOG.  The high-range  relationship
should prove satisfactory for a first  order estimate over the entire
range.

STATISTICAL ANALYSIS

A statistical analysis was performed on the  correlations of BOD5 with
TOG to determine the accuracy with  which the BODg can be  calculated
from the TOG.  For each pair of BOD5 and TOG analyses, the predicted
BOD5 was  calculated using the appropriate correlation.  The deviation
of the predicted BOD5 from the measured BOD5 was calculated as a per-
cent of the predicted BOD5.  The distribution of the error in the pre-
dicted BOD5 was determined by plotting this error  on probability paper
in Figures 28 through 30.  A summary of the accuracy on the corre-
lations at the 80 percent confidence level is  presented in  Table 6.

CONCLUSIONS

The literature indicates that the BOD5 of various wastewater can be cor-
related with their TOC.   This  report has shown that a correlation be-
tween BOD5 and TOC exists for GEL sewage.

The BOD5  of the sewage was shown to be equal to 1. 5 times  the TOC for
a TOC < 300 mg/liter and equal to 1. 8 times the TOC for a
TOC > 300 mg/liter.  The prediction of BOD5 can be simplified with
little loss in accuracy by using the high range relationship for  all sewage
strengths.

                                 98

-------
              2000
              1800-
              1600-
              1400-
              1200-


CONCENTRATION
OF 5-DAY BOD   1000
(mg/liter)
               800-
               600"
               400-
BOD5  = 1.8 x TOC
                                                 BOD5  =  1.5 x TOC
                                                       • FIRST TEST SERIES

                                                       X SECOND TEST SERIES
   200         400         600         800
 CONCENTRATION OF TOTAL ORGANIC CARBON (mg/liter)
                                                                             1000
     Figure 27   HIGH-RANGE AND  LOW-RANGE CORRELATION OF
                  BOD5  WITH TOC  FOR  GEL SEWAGE
                                         99

-------
PERCENT
ERROR
IN THE
PREDICTED
BOD.
            30
            20
            10
           -10
           -20
           -30
           -40
           -50
              2    5   10   20  30     50     70  80    90   95   98
                PERCENT OF THE VALUES LESS THEN THE INDICATED VALUES


    Figure 28  ACCURACY OF  HIGH-RANGE  CORRELATION  OF
               BOD5 WITH TOG FOR  CEL  SEWAGE

                (BOD5 =  1.8 x  TOG for TOG  > 300)
                              100

-------
         60
         50
         40
         30
         20
         10

PERCENT
ERROR
IN THE      0
PREDICTED
BOD5

        -10
        -20
        -30
        -40
        -50
Figure 29
           2    5    10   20  30 40  50 60 70 80   90  95  98
             PERC'ENT OF THE VALUES THAN THE  INDICATED VALUES

            ACCURACY OF LOW-RANGE CORRELATION OF
            BOD5 WITH  TOG FOR GEL  SEWAGE

            (BOD5 = 1.5  x TOG for TOG < 300)
                          101

-------
       60
       50
       40
       30
       20
       10
PERCENT
ERROR
IN THE
PREDICTED
BODC
       -10
       -20
       -40
       -50
                                                      7
             2    5    10    20  30 40 50  60  70  80   90  95    98  99
             PERCENT OF THE VALUES LESS THEN THE INDICATED VALUE
  Figure 30   ACCURACY OF SIMPLIFIED  CORRELATION OF
              BOD5 WITH  TOG FOR GEL SEWAGE

               (BOD5  = 1.8 x TOG  for  ALL TOG)
                              102

-------
           Table 6   SUMMARY OF ACCURACY
              OF BOD   TOG RELATIONSHIPS
    Waste
    Correlation
            Percent Error in  the
             Predicted BOD  at

           80 Percent Confidence
                   Level
CEL Sewage

(High Range)
BOD   =  1. 8 x TOC
                             -17  to  17
    TOC
300
CEL Sewage

(Low Range)
BOD   = 1. 5 x  TOC

    TOC < 300
                  -15  to  20
CEL Sewage
 (Simplified
Correlation)
BOD   = 1. 8 x  TOC

       All  TOC
                  -9 to 26
                              103

-------
Table 7   SUMMARY  OF  RESULTS FROM SOLIDS  DISTRIBUTION TESTS
Sewer
Descrip-
tion



18 Inch
Sewer






12 Inch
Sewer




Number
of
Tests
Run
3
1
2
2
2
3
3
2
1
2
2
2
3
3
1
1
Pipe
Slope
0.001
0.001
0. 001
0.002
0.002
0. 004
0.004
0.002
0.002
0.002
0. 004
0. 004
0.006
0.006
0.008
0.008
Sewage
Base
Flow
(gpm)
10
30
50
10
50
10
50
10
20
30
10
30
10
30
10
10
Average
Quantity
of SS
Deposited
in the
Sewer
(Ibs)
4.36
5.70
3.75
3.50
5. 51
3.26
4.44
1. 89
4.37
3.54
2. 34
2.21
1.66
3.01
6.93
-' 0. 93
Average Proportional
Distribution of SS
Along the Pipe Length
In the
First
267 ft
0.495
0.426
0.356
0.483
0.441
0. 500
0.481
0. 568
0.490
0.413
0.483
0.410
0.491
0.423
0.384
0.291
In the
Next
255 ft
0.376
0.426
0.476
0.400
0.392
0.315
0.296
0.214
0.230
0.245
0.284
0.303
0.237
0.299
0.301
0.347
In the
Next
108 ft
0.053
0.070
0. 088
0.050
0. 078
0.083
0. 105
0.106
0. 109
0. 112
0.096
0. 121
0.099
0.098
0.223
0. 120
In the
Last
160 ft
0.076
0. 078
0.080
0. 067
0. 089
0. 102
0. 118
0. 112
0. 171
0.230
0. 137
0. 166
0. 173
0. 180
0. 092
0. 242
Average
Quantity
of VSS
Deposited
in the
Sewer
(Ibs)
2.68
2.05
1.97
2.08
1.89
1.88
2.42
1.07
1.62
2. 15
1.48
0.83
1.00
1.61
1. 57
0.36
Average Proportional
Distribution of VSS
Along the Pipe Length
In the
First
267 ft
0.441
0.351
0.261
0.392
0.388
0.405
0.385
0. 505
0.409
0.312
0.396
0.353
0.413
0.408
0.302
0. 157
In the
Next
255 ft
0.430
0.470
0. 510
0.497
0.417
0.379
0.339
0.186
0.227
0.268
0.335
0.315
0.281
0.318
0.255
0.261
In the
Next
108 ft
0.047
0.081
0. 114
0.044
0. 101
0. 097
0.128
0. 133
0. 130
0. 128
0. 092
0. 138
0. 113
0. 123
0. 144
0.321
In the
Last
160 ft
0.082
0.098
0. 115
0.067
0. 144
0. 119
0.148
0. 176
0.234
0.292
0. 177
0. 194
0. 193
0. 151
0.299
0.261
Average
Quantity
of TOG
Deposited
in the
Sewer
(Ibs)
1.22
1.29
0.97
0.80
0.88
1.32
1.41
0.56
1.16
1.09
0.89
0.67
0.77
1. 11
0.62
0.49
Average Proportional
Distribution of TOG
Along the Pipe Length
In the
First
267 ft
0.267
0.243
0.219
0.387
0.259
0.332
0.340
0.314
0.268
0.222
0.472
0.426
0.295
0.303
0. 275
0.282
In the
Next
255 ft
0.466
0.470
0.474
0.382
0.387
0.342
0.313
0.282
0.258
0.233
0.212
0.253
0.275
0.300
0.330
0.229
In the
Next
108 ft
0.092
0. 114
0. 136
0.092
0.148
0.165
0.167
0.208
0.182
0.156
0. 116
0.129
0. 180
0. 157
0. 152
0. 191
In the
Last
160 ft
0.175
0.173
0.171
0.139
0.206
0.161
0.180
0.196
0.292
0.389
0.200
0. 192
0.250
0.240
0.243
0.298
                                                                                            W
                                                                                            en
                                                                                            a
                                                                                            IT1
                                                                                            H
                                                                                            cn
                                                                                            a  ^
                                                                                            co  TJ
                                                                                            ffi  H
                                                                                            w
                                                                                            E
                                                                                            O
                                                                                            2

                                                                                            H
                                                                                            H
                                                                                            en

-------
Table 8   SUMMARY OF RESULTS FROM  CLEAN-WATER
                FLUSH TESTS (1  of 9)
Obser-
vation
No.



1
2
3
4
5
6
7
8
9
10
11
1Z
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
SS
Clean-
sing
Eff.
-CESS~
(%)
35. 1
24.0
20.4
26.7
79.3
71. 0
59.7
64.2
57.9
11. 5
15. 5
15. 8
71. 6
68.9
64.0
57.3
61.4
45. 5
45.8
44. 1
78. 7
70.8
«6.3
58.2
27.6
25.4
25.0
22.9
61.3
44.6
40. 6
36.0
9.8
15.2
9.6
16.9
77.8
67.3
60. 0
64.4
55.4
32.8
36.2
35.9
75.9
75.6
73.8
43. 8
66.2
50.7
50.6
51.3
67.8
70.4
70.7
68. 3
89.6
67. 1
61.4
64.3
90. 1
85. 2
77.2
VSS
Clean-
sing
_Eff.
"CEVSS"
(%)
35.5
28.6
27.8
26.7
84.3
72.9
63. 8
70.2
73.9
7.9
16.3
19.3
75.5
71. 1
67.5
63. 1
87. 5
68.3
70. 5
64. 1
93.0
88. 1
86.4
72.2
44.6
29.0
32.6
35. 2
74. 0
51.7
51.6
47.3
0.0
0.0
0.0
0. 0
77.9
65.6
58. 6
66.0
59. 5
44.4
46.9
46.8
76. 1
77.3
75.4
4o. 5
74.4
63.4
63. 1
63.6
77.4
77. 7
77.4
73.8
91. 5
76.8
71.4
74.2
90. 1
86.9
79.4
TOC
Clean-
sing
Eff.
~CETOC~
(%)
0. 0
0. 0
0.0
0. 0
0.0
0.0
0.0
0.0
51.6
43.0
37.6
35.0
46.7
51. 5
49. 5
47. 5
69.4
63. 0
62. 1
63. 0
63.7
66. 7
65.6
61.4
31. 7
39.0
35. 8
39.7
63.9
50. 7
52.9
43.3
2.9
18.4
20.4
34.0
30.7
14. 2
17. 1
33.3
21.6
21. 3
29.4
38.0
54. 6
62.3
65.2
55. 2
64.6
65.2
60. 5
62. 5
45.3
63.6
68.3
69.1
81.0
76. 5
68. 7
74. 1
37. 6
52. 1
51.2
Total
Length
of
Sewer
-L-
(ft)
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
Pipe
Slope


-So-

. 001
. 001
.001
.001
.002
. 002
.002
.002
.001
.001
.001
. 001
. 002
. 002
.002
. 002
. 001
.001
. 001
.001
. 002
. 002
. 002
. 002
. 001
. 001
. 001
.001
. 002
. 002
. 002
. 002
. 001
. 001
. 001
. 001
. 002
. 002
. 002
.002
. 001
.001
. 001
. 001
. 002
. 002
. 002
. 002
. 001
. 001
.001
. 001
.002
. 002
.002
.002
. 001
. 001
. 001
. 001
. 002
. 002
.002
Sewage
Base
Flow

-QB-
(gpm)
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
30
30
30
30
20
20
20
20
30
30
30
30
20
20
20
20
30
30
30
30
20
20
20
Flush
Rate


-QF-
(gpm)
711
711
711
711
250
250
250
250
1519
1519
1519
1519
1053
1053
1053
1053
1639
1639
1639
1639
1102
1102
1102
1102
451
451
451
451
632
632
632
632
1543
1543
1543
1543
1269
1269
1269
1269
525
525
525
525
294
294
294
294
1904
1904
1904
1904
1063
1063
1063
1063
2768
2768
2768
2768
2094
2094
2094
Flush
Volume


-VF
(gal.)
368
368
368
368
680
680
680
680
380
380
380
380
527
527
527
527
355
355
355
355
331
331
331
331
165
165
165
165
190
190
190
190
257
257
257
257
233
233
233
233
674
674
674
674
662
662
662
662
698
698
698
698
674
674
674
674
692
692
692
692
698
698
698
Pipe
Diameter



(in)
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12

                         106

-------
Table 8   SUMMARY OF RESULTS FROM CLEAN-WATER
                 FLUSH TESTS (2 of 9)
Obser-
vation
No.



64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
SS
Clean-
sing
Jpff.
-CESS~
(%)
81. 1
63.6
28.4
25.1
22. 8
57. 5
39. 8
36. 1
33.8
58.9
28. 0
28.0
26.2
68.4
61.7
58.8
54. 9
63.7
33.6
29. 1
22. 1
77.7
59.8
55.6
48. 8
51. 5
39.3
37. 5
32.9
80.3
59. 0
57.4
58.3
57. 1
37.4
39.9
29. 0
61.4
41.4
36. 0
32.0
82.7
65.0
59. 8
54. 5
84.3
64.6
60.4
53.4
63. 1
30. 1
28.9
25.2
28.4
21.7
21.6
18.4
57.6
24.5
25.7
25.9
73. 5
47. 0
VSS
Clean-
sing
_E£f.
~CEVSS~
(%)
81.8
65. 5
29.2
26. 1
25.6
64.3
39.7
36.4
37. 3
55. 6
35.9
36. 0
35.3
76.4
63.9
62. 1
61. 0
54. 8
47. 2
43. 5
35. 5
86. 5
63.3
59.6
52.3
60.3
51.3
50.4
45. 3
86.4
76.2
74.9
66.7
56. 6
45. 5
40. 9
35. 5
67. 0
40.3
35. 1
35. 1
83.7
67.4
62.3
57. 5
85.5
60. 6
56. 1
52.2
61.2
35. 5
34.6
32. 2
35.8
23.3
24. 1
23. 1
64.4
26. 1
27.7
29. 1
73.2
42.6
TOC
Clean-
sing
Eff.
"CETOC~
(%)
65. 5
67.7
28. 2
30.7
32. 1
43. 8
28.9
36.4
39.7
49.3
40. 7
36.3
32.8
61. 0
41.4
40. 6
42.8
35.6
45. 5
44.0
41.3
70. 9
52. 6
53. 1
52. 2
74. 6
57. 2
53.4
52. 3
54. 7
51.4
56.4
54. 7
43. 3
52. 6
51.9
52. 0
39.6
38. 8
36. 1
41. 7
77.7
71. 8
71.2
69. 8
76.7
56. 0
60.4
60.2
77. 2
73. 2
72.7
73. 3
47. 1
47. 0
50. 8
52.2
64.2
56.9
57.0
56. 8
65.3
50.2
Total
Length
of
Sewer
-L-
(ft)
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
Pipe
Slope


-So-

. 002
. 001
. 001
. 001
. 001
.002
.002
. 002
.002
. 001
. 001
. 001
. 001
. 002
. 002
. 002
. 002
. 001
. 001
. 001
. 001
. 002
. 002
. 002
. 002
. 001
. 001
. 001
. 001
. 002
. 002
.002
. 002
. 001
. 001
. 001
. 001
. 002
. 002
. 002
. 002
. 001
. 001
. 001
.001
. 002
. 002
. 002
. 002
. 001
. 001
. 001
. 001
. 002
. 002
. 002
. 002
. 001
. 001
. 001
. 001
. 002
. 002
Sewage
Base
Flow

-QB-
(gpm)
20
30
30
30
30
20
20
20
20
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
30
30
30
30
20
20
20
20
30
30
30
30
20
20
20
20
30
30
30
30
20
20
20
20
30
30
30
30
20
20
Flush
Rate


-V
(gpm)
2094
560
560
560
560
343
343
343
343
3031
3031
3031
3031
2205
2205
2205
2205
1732
1732
1732
1732
1361
1361
1361
1361
1680
1680
1680
1680
1139
1139
1139
1139
1837
1837
1837
1837
1372
1372
1372
1372
2695
2695
2695
2695
1815
1815
1815
1815
882
882
882
882
205
205
205
205
964
964
964
964
840
840
Flush
Volume


-VF
(gal. )
698
355
355
355
355
355
355
355
355
404
404
404
404
257
257
257
257
404
404
404
404
386
386
386
386
196
196
196
196
190
190
190
190
398
398
398
398
343
343
343
343
404
404
404
404
302
302
302
302
300
300
300
300
300
300
300
300
300
300
300
300
300
300
Pipe
Diameter



(in. )
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
                            107

-------
Table 8   SUMMARY OF RESULTS  FROM CLEAN-WATER
                FLUSH  TESTS  (3  of 9)
Obier-
vation
No.



127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
SS
Clean-
sing
Eff.
-CESS-
(%)
42. 1
37.5
87.9
75.2
71.8
65.9
86.2
74. 5
71.7
63. 1
89.0
82.4
78.0
74.6
84.4
73.6
69.7
62.8
54. 5
47. 5
45.2
41.7
60. 3
55. 5
55. 3
40.5
89.0
89.0
87.2
85.0
84.2
77.2
73.0
64.2
89. 2
84.0
82.5
80. 1
87.0
80.0
73.9
64.9
84.7
80. 1
77.8
75.3
30.2
41. 1
44.8
39.5
66.6
71. 2
70. 1
68.6
39.9
33.9
33.0
37.7
81. 6
73.3
70.7
68. 1
79. 0
vss
Clean -
• Ing
_Eff.
~CEVSS
(%)
38. 8
37.9
88.7
80.6
77. 7
71. I
86.6
72.7
70. 1
62.9
90. 6
85.4
81.0
77. 5
84. 5
71.9
68.0
62.0
70. 1
56.3
53. 1
48.4
71. 2
62.7
61.6
45. 1
94. 5
94. 1
92.4
89.8
82.6
75.8
71. 1
59.7
87.5
86.3
85.2
82.4
78.3
74.0
66. 8
58. 6
91.8
87. 0
84. 5
82. 1
46.6
46.1
50. 1
41.5
63.9
67.0
64.6
63.2
69. 8
68.4
67. 2
70.4
87.3
74. 1
70.9
68. 5
86. 0
TOC
Clean-
ling
Eff.
"CETOC"
(%)
43. 6
47.7
80.0
76.7
68. 3
65. 1
58.8
58.7
60. 2
58.9
84.0
85.6
82.0
78.8
72.3
74. 5
47.2
52. 1
52.3
50.0
46.3
44.0
41. 3
41.4
46.4
38. 5
87.9
86.4
80.4
71.0
50.7
40.4
42.4
46. 5
88.6
91.6
88.7
86.6
80.8
77.8
70.0
61.4
65.2
75. 1
65.7
60. 1
44. 8
37.9
32.8
41. 5
40.9
52. 1
45.3
47.4
16.4
25. 6
34.4
51.4
73.6
66.5
63.7
64.9
61.4
Total
Length
of
Sewer
-L-

-------
Table 8   SUMMARY OF RESULTS FROM CLEAN-WATER
                 FLUSH TESTS (4 of  9)
Obser-
vation
No.



190
191
192
193
194
195
196
197
198'
199
200
201
202
203
204
205
206
207
208
209
210
211 '
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
SS
Clean-
sing
Eff.
•CESS'
(%)
75.0
70.2
66.9
77. 1
73. 1
70.3
67.3
81.9
62.4
65. 1
56. 2
83.3
63.2
50.3
49.2
73. 5
36.6
27.9
28.3
83. 1
43.1
41. 0
39.3
31. 5
21. 0
18.7
24. 1
66. 1
61.9
58. 1
54. 1
83.8
57. 1
49. 1
46.5
87. 6
81.4
77.2
72. 2
86. 8
81.8
79.2
75. 5
86.5
68. 1
64.2
59.1
56.5
48.2
43.4
40. 6
36.7
29.4
19.5
21.7
69.2
56.5
50.5
40. 5
12.3
16.4
19.1
16.2.
VSS
Clean-
sing
Eff.
~CEVSS~
(%)
83.4
80.2
79. 1
84.0
82.4
81. 0
79.4
78.9
51.8
57. 1
55.8
79.0
73.2
69.4
67. 0
49.7
23. 1
29.6
36. 2
91. 8
41.6
40. 7
4,0.3
47. 0
32. 5
28. 5
33.9
66.4
65.7
62.6
60. 2
79.4
56.3
49.3
48.2
84.7
82.6
78. 2
73. 5
86.8
80. 1
77.4
72.8
86.5
77. 2
73.3
66.9
36.0
43. 3
42.2
41.9
40.0
36.6
26.4
29.0
71.6
54. 9
50.4
43.4
25.0
21.4
25.8
22.2
TOG
Clean-
sing
Eff.
~CETOC~
(%)
68.4
67.4
68. 8
69. 5
71.4
64.4
62.3
64.7
57.7
47. 2
52.6
76. 5
62. 2
56.3
50.9
26.6
13.1
18. 1
35.6
69. 8
56.3
57. 2
60. 5
47. 8
33. 5
36.2
46.7
31.6
53. 5
52.0
53.9
79.7
59. 0
57.0
65. 1
81. 9
83.3
79.3
78. 2
83.6
80.7
77.9
75.7
88. 2
82.0
75. 5
74. 1
67.4
47.9
52. 0
49.9
40.3
50. 3
43.2
45.2
51. 7
43.3
43.7
39.4
32. 5
36.4
36.4
35. 0
Total
Length
of
Sewer
-L-
(ft)
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
Pipe
Slope


-So-

. 002
. 002
. 002
. 001
. 001
. 001
. 001
. 002
.002
.002
. 002
.001
. 001
.001
. 001
. 002
. 002
. 002
. 002
.001
. 001
. 001
. 001
. 002
. 002
. 002
. 002
. 001
.001
.001
. 001
. 002
. 002
.002
.002
. 001
. 001
.001
.001
. 002
. 002
.002
.002
.001
. 001
. 001
.001
.002
. 002
.002
. 002
.001
.001
. 001
.001
.002
. 002
. 002
.002
. 001
. 001
. 001
. 001 ,
Sewage
Base
Flow

-QB-
(gpm)
30
30
30
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
10
10
10,
10
30
30
30
30
30
30
30
30
20
20
20
20
30
30
30
30
20
20
20
20
50
50
50
50
10
10
10
10
50
50
50
50
Flush
Rate


-v
(gpm)
1029
1029
1029
2021
2021
2021
2021
1878
1878
1878
1878
343
343
343
343
196
196
196
196
790
790
790
790
679
679
679
679
1212
1212
1212
1212
1580
1580
1580
1580
2572
2572
2572
2572
2094
2094
2094
2094
I960
I960
I960
I960
294
294
294
294
624
624
624
624
1102
1102
1102
1102
269
269
269
269
Flush
Volume


-VF-
(gal. )
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
300
300
300
300
Pipe
Diameter



(in.)
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
                            109

-------
Table 8   SUMMARY OF RESULTS FROM CLEAN-WATER
                FLUSH  TESTS (5  of 9)
Obser-
vation
No.



253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
SS
Clean-
sing
Eff.
~CESS~
(%)
71.9
66.0
62.3
56.7
46.6
40.9
33.4
27.2
92.4
85. 9
82.7
73.4
61.9
49. 1
48.8
45.9
65.6
61.5
60. 3
53.6
82.2
72.9
70.6
67.7
64. 6
59.3
59. 1
56. 6
82.0
56.6
56.0
55.2
77.2
41.8
38.2
35.5
86. 1
77.0
75.4
71.7
85.2
81.0
78.0
72.8
85.7
77.3
72.9
70.4
63. 0
51.7
45.6
46.3
81. 1
63.2
60. 8
58.7
30.4
21.2
20. 2
23. 5
51. 5
41.7
41.8
VSS
Clean-
sing
Eff.
"CEVSS"
(%)
81. 8
73.4
70. 1
65. 6
45. 1
53. 5
44.4
39.4
90.9
85. 0
82.9
76. 8
63.2
57.3
58.0
56.0
74. 8
67. 5
66.9
63. 8
88. 8
81.7
80. 2
78. 2
58.7
59.9
60.9
62.0
86.0
60. 5
59.8
59.0
74.2
52. 1
49.6
46. 5
86.8
81.4
79. 8
75.9
92.1
87.3
84.7
80.9
91. 0
86. 5
83. 0
80. 5
44.2
50.5
46.9
52.4
89.5
74.6
71.6
69.3
43. 8
30.8
29. 1
33.9
57.4
47.8
47. 7
TOG
Clean-
sing
>Sff.
"CETOC"
(%)
68.4
68. 1
66. 8
57.7
46.7
45.6
39. 5
40. 1
75.8
71.3
72.4
63. 8
76. 8
66. 2
55.4
56.4
82.0
66.3
70. 1
54. 1
12.3
52.9
54.0
56. 1
66.4
67. 3
58. 2
63. 1
65. 5
39.6
43.4
47. 9
47. 8
34.7
43.4
52. 2
88. 1
81. 8
70. 2
69.8
92.2
81. 0
82.0
77. 5
40.4
70. 0
65.4
65.3
33.4
50. 2
42.4
53.0
90. 3
58. 5
56.4
58. 5
0.0
0. 0
0.0
0. 0
58. 3
50. 7
53. 6
Total
Length
of
Sewer
-L-
(ft)
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
Pipe
Slope


-So-

.002
.002
.002
. 002
.001
.001
.001
. 001
.002
.002
.002
. 002
.001
. 001
. 001
. 001
.002
.002
.002
. 002
. 001
. 001
.001
.001
. . 002
.002
.002
.002
. 001
.001
. 001
. 001
. .002
.002
.002
. 002
. 001
.001
. 001
.001
. 002
.002
.002
.002
.001
. 001
.001
.001
.002
.002
. 002
. 002
.001
. 001
. 001
.001
. 002
. 002
.002
.002
. 001
.001
.001
Sewage
Base


-QB-
(gpm)
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
50
50
50
50
10
10
10
10
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
50
50
50
Flush
Rate


^V
(gpm)
1078
1078
1078
1078
759
759
759
759
2058
2058
2058
2058
441
441
441
441
245
245
245
245
385
385
385
385
1176
1176
1176
1176
330
330
330
330
698
698
698
698
3234
3234
3234
3234
1127
1127
1127
1127
2499
2499
2499
2499
1065
1065
1065
1065
1323
1323
1323
1323
238
238
238
238
1506
1506
1506
Flush
Volume


-v
(gal. )
600
600
600
600
900
900
900
900
900
900
900
900
900
900
900
900
900
900
900
900
600
600
600
600
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
600
600
600
600
300
300
300
Pipe
Diameter



(in.)
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
IB
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18

                         110

-------
Table 8   SUMMARY  OF RESULTS FROM CLEAN-WATER
                FLUSH TESTS (6 of 9)
Obser-
vation
No.



316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
SS
Clean-
sing
Eff.
•CESS'
(%)
40.3
69.4
51. 7
49.4
41. 5
80. 0
54.6
54.3
52.3
90.7
79.6
73. 1
67. 1
68. 2
43. 1
41.8
39.2
78. 0
66.7
62.6
57.4
80. 1
25.7
24.2
24. 5
18.3
12.4
13.0
18.0
87. 8
61. 1
57.4
54. 1
72. 8
51.7
46. 1
45. 1
92.6
78. 1
75.6
70.7
89.8
70.4
63. 0
57.6
93.4
92.0
90. 2
87. 1
93.6
90. 8
89.3
86. 5
85.5
72. 2
69.2
64.9
80. 8
75.4
73.4
65.2
94. 1
91.8
VSS
Clean-
sing
Eff.
~CEVSS~
(%)
46.7
74. 5
57.2
55.9
49.4
75.8
65.4
64.8
61. 8
92.6
81.2
74.7
69. 6
65. 8
53.3
53. 0
52.0
82.6
72. 5
69.7
67. 0
86.7
31. 5
29.4
30.3
32. 5
18.7
18. 2
24.2
92. 1
75. 1
71.9
69.2
71.7
55.4
51.4
52.2
96.7
85. 6
83.0
79.2
89.7
73.3
64.7
60.7
95.9
95.6
95. 1
93.0
94.9
92.2
90.8
87.0
89.4
81.3
77.6
74.4
80. 5
71. 6
70.2
70. 8
96.7
95. 1
TOG
Clean-
sing
Eff.
"°ETOC"
(%)
52.2
51. 0
40.4
51. 5
51. 8
70.6
63.9
60. 5
58. 5
83.9
69.7
66.6
59.4
49. 6
43. 1
46. 0
51.4
59.7
45.9
47. 8
51.9
94.8
30.4
32.4
38. 5
30. 5
21. 8
30. 5
39. 0
89.0
74.2
73.3
70.7
65.7
50. 1
56.4
63.4
54.9
68.9
66.3
64.2
84.2
55.4
39.4
52. 5
79.2
82.4
68.4
67.4
58. 7
45. 8
34.8
40.3
67.0
58.2
52.9
52.2
65.9
57.4
53.4
50. 9
54. 1
53. 2
Total
Length
of
Sewer
-L-
(ft)
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
Pipe
Slope


-So-

. 001
. 002
. 002
. 002
. 002
. 001
. 001
.001
.001
. 002
. 002
.002
. 002
. 001
. 001
.001
.001
. 002
. 002
. 002
. 002
.001
.001
.001
.001
. 002
. 002
.002
. 002
.001
. 001
.001
. 001
. 002
. 002
. 002
.002
. 001
. 001
.001
.001
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
.004
. 004
. 004
. 004
. 002
.002
. 002
. 002
. 004
. 004
.004
.004
. 002
. 002
Sewage
Base


-QB-
(gPm)
50
10
10
10
10
50
50
50
50
20
20
20
20
50
50
50
50
20
20
20
20
10
10
10
10
20
20
20
20
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
10
10
Flush
Rate


-v
(gpm)
1506
171
171
171
171
1947
1947
1947
1947
1543
1543
1543
1543
1029
1029
1029
1029
1065
1065
1065
1065
1764
1764
1764
1764
257
257
257
257
1690
1690
1690
1690
1617
1617
1617
1617
710
710
710
710
1347
1347
1347
1347
2940
2940
2940
2940
1911
1911
1911
1911
1323
1323
1323
1323
1568
1568
1568
1568
441
441
Flush
Volume


-v
(gal. )
300
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
Pipe
Diameter



(in.)
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
                           111

-------
Table 8   SUMMARY OF RESULTS  FROM CLEAN-WATER
                 FLUSH TESTS  (7  of 9)
Obser-
vation
No.



379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
SS
Clean-
sing
Eff.
"CESS"
(%)
90. 5
89. 2
83. 1
73.4
72.4
67. 7
80. 6
61. 8
59. 0
57. 3
56.7
48.8
46.3
40. 8
77.0
78.4
76.7
73. 5
83. 2
81.3
80. 6
76.4
88.6
68.2
61. 7
60. 1
86.4
81. 2
78. 5
71. 6
49. 8
61.7
59.7
58. 5
83. 5
81. 6
80.2
77.2
71.8
66.0
66.0
66. 7
78. 7
76. 1
74. 3
73.7
72. 0
65.4
62. 8
61. 0
85.6
80. 3
78.6
74. 7
82.0
75. 7
75. 0
71. 6
84. 1
76. 5
67.4
63.4
88. 1
VSS
Clean-
sing
Eff.
~CEVSS~
(%)
94.2
93. 1
89.2
81. 6
81. 8
76.2
85.8
66.8
64. 0
62.4
66.9
56.9
48. 1
46. 1
76. 0
80.0
78. 1
74.9
91.9
89. 8
88.4
83. 1
90. 0
67. 1
64. 0
61. 1
93. 3
87. 2
85. 2
78. 3
52.4
63.3
59.6
58.7
88. 5
85.7
81. 5
81. 9
79.9
74. 3
74. 6
74. 2
80. 2
79.0
79. 0
77.3
68. 1
66. 2
63. 8
64. 1
89. 1
83.3
80.7
78. 2
87. 6
84. 0
83. 0
78. 5
84. 7
76.4
65. 0
60. 9
91. 9
TOC
Clean-
sing
Eff.
"CETOC
(%)
49. 8
50. 9
70.4
46. 0
34.6
35. 0
43. 8
36. 5
27. 5
25. 0
60.3
43.2
39.3
17.9
50.3
62.4
59.4
56.7
84.7
76.3
70. 1
66. 2
38.6
41. 8
43.9
44.0
78.3
61. 8
41. 2
42. 5
41. 7
53. 3
50. 5
45. 9
76.3
67. 8
64. 1
61. 0
63. 8
44. 1
46. 2
47.2
63. 1
55.6
43. 1
45.4
37.4
38.8
39. 0
39.4
81. 1
65.7
61. 1
69.4
68.3
67.7
67. 7
62. 0
79. 5
71. 5
58. 5
54. 1
82.9
Total
Length
of
Sewer
-L-
(ft)
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
Pipe
Slope


-So-

. 002
. 002
. 004
. 004
. 004
. 004
. 002
. 002
. 002
. 002
. 004
. 004
. 004
.004
. 002
. 002
. 002
.002
. 004
.004
.004
. 004
.002
. 002
. 002
. 002
. 004
. 004
.004
. 004
. 002
. 002
. 002
. 002
. 004
. 004
. 004
. 004
. 002
. 002
. 002
. 002
. 004
. 004
. 004
. 004
.002
. 002
. 002
.002
. 004
. 004
. 004
. 004
. 002
.002
.002
. 002
. 004
. 004
.004
.004
. 002
Sewage
Base


-°B
(gpm)
10
10
30
30
3-0
30
10
10
10
10
30
30
30
30
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
10
10
10
10
30
30
30
30
10
Flush
Rate


-v
(gpm)
441
441
294
294
294
294
343
343
343
343
196
196
196
196
2989
2989
2989
2989
1862
1862
1862
1862
1127
1127
1127
1127
1225
1225
1225
1225
441
441
441
441
245
245
245
245
343
343
343
343
245
245
245
245
882
882
882
882
980
980
980
980
980
980
980
980
882
882
882
882
931
Flush
V olum e


-V
(gal. )
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
600
600
600
600
600
600
600
600
600
600
600
600
600
600
600
600
300
Pipe
Diameter



(in.)
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
1?
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
                           112

-------
Table 8  SUMMARY OF RESULTS FROM CLEAN-WATER
                FLUSH TESTS (8 of 9)
Obser-
vation
No.




442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
SS
Clean-
sing
Eff.
•CESS~
(%)

81.9
80.3
78.3
90.4
80.5
79.9
74.8
81.0
56.4
55.7
51.6
93.0
87.6
85.7
82.7
94.0
88.3
85. 2
83.0
87. 6
83. 5
81.2
76.6
90. 1
61.4
56.7
52.6
89.2
79.4
76.9
72.9
89.9
79.9
78. 5
77. 1
81.7
75.6
72.8
69.3
56. 1
29.0
25.6
22.7
77.9
61. 1
55.6
53.0
83.3
75.2
72.0
66. 1
87. 1
83.8
81.5
72.8
73.1
60.2
60.0
57.5
81.2
76.2
72. 5
67.5
VSS
Clean-
sing
_Eff.
"CEVSS"
(%)

87.4
85.9
83.9
92.3
82.7
82.7
80. 1
77.6
61.3
59.5
54.9
92.3
88. 1
85. 5
83.4
0. 0
0.0
0.0
0.0
0.0
0. 0
0.0
0.0
88. 1
62.4
57. 1
52.4
90. 5
80.4
77.0
71.9
92.3
85.4
83. 9
82.7
83.3
75.9
73.0
68.8
63.6
35.9
31. 0
27. 5
78. 1
61.7
56.7
55.2
80.4
75.7
72.9
67.8
90. 2
85.8
83.6
75. 5
68.9
58. 7
60. 2
57.8
83.7
79.8
75. 5
67.7
TOG
Clean-
sing
_E£f.
"CETOC"
(%)

78.3
77. 2
77.5
92.9
84.7
77.2
74.8
25.3
33.4
32.2
29.3
46. 1
33.9
32.6
35. 5
77.4
76.3
75.4
70.4
46.2
45.3
42. 7
47.6
64.9
29.6
20.2
12.9
57. 2
46. 9
52.4
55.7
66.0
49.7
46.3
45.0
60. 1
33. 2
19.4
30. 5
56.3
23.0
19.3
27.2
27.9
17. 8
23. 9
31.4
70. 5
57.9
55. 5
52.0
52.9
55.8
54.2
46. 5
53. 2
53.7
50. 7
53. 5
59.4
56.9
54.4
55.4
Total
Length
of
Sewer
-L-.
(ft)

527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
Pipe
Slope


-So-


. 002
.002
. 002
. 004
. 004
.004
.004
. 002
.002
.002
. 002
. 004
. 004
. 004
. 004
. 004
.004
.004
.004
. 006
. 006
. 006
. 006
. 004
.004
. 004
. 004
.006
. 006
. 006
.006
. 004
. 004
.004
. 004
. 006
. 006
. 006
. 006
. 004
. 004
.004
. 004
. 006
. 006
. 006
. 006
.004
. 004
.004
. 004
.006
. 006
.006
. 006
.004
. 004
. 004
.004
. 006
.006
.006
.006
Sewage
Base


-QB-
(gpm)

10
10
10
30
30
30
30
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
Flush
Rate


-V
(gPm)

931
931
931
1519
1519
1519
1519
931
931
931
931
1715
1715
1715
1715
2989
2989
2989
2989
1960
1960
1960
1960
1911
1911
1911
1911
1470
1470
1470
1470
490
490
490
490
294
294
294
294
98
98
98
98
220
220
220
220
2450
2450
2450
2450
1911
1911
1911
1911
1470
1470
1470
1470
1176
1176
1176
1176
Flush
Volume


-v
(gal. )

300
300
300
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
Pipe
Diarrjeter
'


(in.)
t
18
18
18
12
12
12
:?
13
18
1«
18
12
12
12
12
18
18;'
18
18"
12,
12
12
12;
18
18,
18r
18>
121
12
12'
12
18:
18',
!8;
18,
12
1 2-
12
12,,
18,
is;
18'
18
12
12''
12
12.
18
18
18
18
12
12
12
12!
18^
18'
18'
18
12
12;
12l;
•12'
                           113

-------
Table 8  SUMMARY OF RESULTS FROM CLEAN-WATER
                FLUSH TESTS (9 of  9)
Obser-
vation
No.
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
ss
Clean-
sing
Eff.
"CESS"
(%)
60. 6
48. 0
38. 6
33.7
49.7
31.2
25.6
19.7
84.7
83.4
8Z.2
81.3
78.9
55.4
57. 1
55.9
89.9
79.3
77. 2
75. 2
93.6
71. 5
71. 0
73. 1
87.9
84.0
81.2
80. 1
92. 5
90.3
88.8
87.6
84.8
61.3
55.7
53.4
83.4
70.0
74.3
64.6
VSS
Clean-
sing
Eff.
~CEVSS~
(%)
51.3
46.4
38.6
36.8
59. 0
39.7
34.3
23.4
84.9
87. 1
86.4
84. 1
82.2
60.4
61.8
57.2
87.3
77. 2
74.7
73.3
88. 8
65.7
65. 5
65. 8
76. 1
74.9
71. 5
71. 8
93.3
91. 7
91.0
89.9
78.6
57. 5
50. 5
47. 8
81. 2
65. 5
63.2
60. 6
TOC
Clean-
sing
Eff.
~CETOC"
(%)
18.7
25. 2
25. 1
21. 6
32.8
32.4
19.9
21. 1
50. 8
65.2
67.2
66.4
73.4
57.4
53.0
56. 1
56. 1
53. 2
52.4
54. 0
64.0
51.2
38.9
42. 1
52. 5
99.9
40. 2
34. 6
61. 0
52.0
45.7
49.4
53. 7
38.4
33. 5
31.9
15. 5
28.2
28.3
36.0
Total
Length
of
Sewer
-L-
(ft)
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
267
527
635
795
267
514
622
782
Pipe
Slope
-So-
. 004
.004
. 004
.004
.006
. 006
.006
. 006
. 004
.004
.004
.004
.006
. 006
.006
. 006
. 004
.004
.004
. 004
. 006
.006
. 006
.006
.004
. 004
. 004
. 004
.006
. 006
. 006
. 006
.004
. 004
. 004
.004
. 006
.006
. 006
. 006
Sewage
Base
-QB-
(gpm)
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
10
10
10
10
30
30
30
30
50
50
50
50
10
10
10
10
50
50
50
50
10
10
10
10
Flush
Rate
-QF-
(gpm)
343
343
343
343
196
196
196
196
196
196
196
196
245
245
245
245
784
784
784
784
1323
1323
1323
1323
1176
1176
1176
1176
1764
1764
1764
1764
1617
1617
1617
1617
1323
1323
1323
1323
Flush
Volume
-VF
(gal. )
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
Pipe
Diameter
(in. )
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
18
18
18
18
12
12
12
12
                          114

-------
Table 9   SUMMARY  OF MAXIMUM FLUSH WAVE  DEPTHS
          OBSERVED IN 12-INCH SEWER (1 of 12)
Obser-
vation
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Maximum
Flush
Wave
Depth
-WD-
(in. )
11. 5
10. 5
10.0
9.3
13. 0
11. 5
11. 8
11.0
7. 1
6. 5
6.3
6. 5
6. 1
6.0
5.9
6.3
12.0
11.0
8. 5
9.0
12. 0
10.3
9.3
8.5
5.0
4. 8
4.8
4. 8
12.0
9.0
7. 8
6. 5
6.3
4. 5
7.0
6.5
12.0
12. 0
11. 0
9.0
6. 5
6.0
6. 1
6. 5
8.0
6.8
6.0
5. 5
Distance
Down-
stream
of Flush
Release
(ft)
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope
-So-
. 002
. 002
.002
. 002
.002
. 002
.002
.002
. 002
. 002
.002
.002
.002
.002
. 002
.002
.002
. 002
. 002
.002
. 002
. 002
. 002
.002
.002
. 002
. 002
. 002
. 002
. 002
.002
. 002
.002
. 002
. 002
.002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
Sewage
Base
Flow
-QB-
(gpm)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
20
20
20
20
20
20
20
20
10
10
10
10
Flush
Rate
-QF
(gpm)
1267
1267
1267
1267
1911
1911
1911
1911
323
323
323
323
294
294
294
294
1029
1029
1029
1029
1878
1878
1878
1878
196
196
196
196
679
679
679
679
1580
1580
1580
1580
2090
2090
2090
2090
294
294
294
294
1103
1102
1102
1102
Flush
Volume
-v
(gal. )
900
900
900
900
900
900
900
900
900
900
900
900
600
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
                             115

-------
Table 9   SUMMARY  OF  MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED IN  12-INCH SEWER (2 of 12)
Obser-
vation
No.





49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
' 68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
Maximum
Flush
Wave
Depth

-W -
D
(in.)
12.0
12. 0
9. 5
8.3
12.0
12. 0
12. 0
9.0
6.3
5. 8
6. 1
6. 1
12. 0
11. 0
11. 0
10. 5
11. 0
8. 5
7.3
6.3
12. 0
11. 5
11. 0
10. 0
12. 0
11.0
7. 8
9. 0
5. 8
5. 3
5. 3
5. 5
4. 5
4. 3
4. 3
4. 0
12. 5
10. 5
10. 5
9. 5
12.0
8. 6
9.4
8. 0
12.0
10. 5
9.0
5. 8
Distance
Down-
stream
of Flush
Release


(ft)
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
9Z
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope



-So-


. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
.002
. 002
. 002
. 002
. 002
Sewage
Base
Flow


-QD
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
10
10
10
10
30
30
30
30
30
30
30
30
10
10
10
10
20
20
20
20
20
20
20
20
20
20
20
20
Flush
Rate



-QTP-
F
(gpm)
1078
1078
1078
1078
2058
2058
2058
2058
245
245
245
245
1176
1176
1176
1176
698
698
698
698
1127
1127
1127
1127
1065
1065
1065
1065
238
238
238
238
54
54
54
54
1543
1543
1543
1543
1065
1065
1065
1065
257
257
257
257
Flush
Volxime



-V -
F
(gal.)
600
600
600
600
900
900
900
900
900
900
900
900
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
600
600
600
600
600
600
600
600
600
600
600
600
                            116

-------
Table 9   SUMMARY OF  MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED  IN  12-INCH  SEWER  (3  of  12)
Obser-
' vation
No.





97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
M aximum
Flush
Wave
Depth

-W_-
D
(in.)
12. 0
9.0
8. 0
6. 5
8.0
8.0
7.3
6.0
10. 0
8.0
8. 5
8.0
10. 5
8.0
7.3
6.0
5. 3
5.8
6.0
6.3
4. 3
4.5
4. 5
4. 5
12.0
12.0
12. 0
10. 0
10. 0
7. 8
6. 5
5. 3
4. 5
5. 5
6.0
6.3
11.3
10. 3
8.8
7.3
12.0
10. 5
8. 0
7. 8
11. 0
8. 5
7. 5
6.0
Distance
Down-
stream
of Flush
Release


(ft. )
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope



-So-


.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
Sewage
Base
Flow


-Q_
B
(gpm)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
Flush
Rate



-<3
F
(gpm)
1617
1617
1617
1617
1347
1347
1347
1347
1911
1911
1911
1911
1568
1568
1568
1568
294
294
294
294
196
196
196
196
1862
1862
1862
1862
1225
1225
1225
1225
245
245
245
245
980
980
980
980
882
882
882
882
1519
1519
1519
1519
Flush
Volume



-V -
F
(gal.)
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
                             117

-------
Table 9   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED IN 12-INCH SEWER (4 of 12)
Obser-
vation
No.





145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
Maximum
Flush
Wave
Depth

-W -
D
(in.)
8.8
7. 5
7.3
5. 5
11. 0
9. 5
10. 5
10. 5
10. 0
6.5
7. 3
5. 5
5. 0
5.0
5. 5
6.0
4. 5
4. 8
4.8
4. 8
11. 0
8. 0
10. 0
8.0
6. 5
4. 5
6. 5
5. 3
4.3
4. 3
4. 5
5. 0
5. 3
6. 0
6.0
6. 0
7.0
5. 3
6.3
4. 3
12.0
6.3
10. 8
9.8
11. 5
7.0
7. 0
5. 8
Distance
Down-
stream
of Flush
Release


(ft)
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope



-So-


.004
. 004
. 004
. 004
.006
. 006
.006
. 006
. 006
.006
. 006
.006
. 006
. 006
. 006
.006
. 006
. 006
.006
.006
.006
. 006
. 006
. 006
. 006
.006
.006
. 006
. 006
.006
. 006
. 006
. 006
.006
.006
. 006
.006
.006
. 006
. 006
. 006
.006
. 006
.006
.006
. 006
. 006
. 006
Sewage
Base
Flow


-Q -
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
10
10
10
10
10
10
10
10
Flush
Rate



-Q^
F
(gpm)
548
548
548
548
1960
1960
1960
1960
1470
1470
1470
1470
294
294
294
294
220
220
220
220
1911
1911
1911
1911
1176
1176
1176
1176
196
196
196
196
245
245
245
245
1323
1323
1323
1323
1764
1764
1764
1764
1323
1323
1323
1323
Flush
Volume



-V,.,
F
(gal. )
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
                              118

-------
Table 9   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED  IN 12-INCH SEWER  (5  of  12)
Obser-
vation
No.





193
194
195
196
197
198
199
ZOO
Z01
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
Maximum
Flush
Wave
Depth

-Wr,
D
(in.)
8. 3
5. 8
5. 3
6. 5
7. 5
6.3
5. 5
5.3
6. 1
4.8
4.3
6.0
6.8
4. 8
3. 5
5.4
8. 0
4. 8
4.0
6.0
7. 5
5. 3
4. 3
5. 8
4. 1
3. 0
3.3
3. 8
5. 0
4. 0
3. 5
4. 5
5. 1
4. 5
4. 0
4. 3
7.3
5. 5
5.4
6.0
5. 0
5. 3
4. 6
5. 5
4.0
3.4
3.0
3. 5
Distance
Down-
stream
of Flush
Release


(ft)
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
Pipe
Slope



-So-


.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
.002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
Sewage
Base
Flow


-Qn
B
(gpm)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
20
20
20
20
20
20
20
20
10
10
10
10
Flush
Rate



-C3
F
(gpm)
1267
1267
1267
1267
1911
1911
1911
1911
323
323
323
323
294
294
294
294
1029
1029
1029
1029
1878
1878
1878
1878
196
196
196
196
679
679
679
679
1580
1580
1580
1580
2093
2093
2093
2093
294
294
294
294
1102
1102
1102
1 102
Flush
Volume



-V_
F
(gal.)
900
900
900
900
900
900
900
900
900
900
900
900
600
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
                             119

-------
Table 9   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED IN 12-INCH SEWER  (6 of 12)
Obser-
vation
No.





241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
Maximum
Flush
Wave
Depth

-W
D
(in.)
6.8
4. 8
4.6
5. 4
7. 8
6.4
5. 3
6.3
5. 8
4. 3
4. 0
5. 5
8. 8
5. 8
6.6
7.0
5. 0
3. 5
3. 0
4. 5
8. 3
6. 0
5. 8
6.3
7. 3
5. 0
5. 0
5. 6
5. 3
4. 5
3.9
5. 0
3. 4
3.0
2. 3
3.0
6. 5
5. 5
4. 5
5. 5
6.4
5. 0
4. 3
5.4
5. 5
4. 5
4.0
4. 0
Distance
Down-
stream
of Flush
Release


(ft)
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
Pipe
Slope



-So-


. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
.002
.002
.002
. 002
. 002
. 002
Sewage
Base
Flow


-
-------
Table 9   SUMMARY OF  MAXIMUM FLUSH  WAVE DEPTHS
          OBSERVED  IN  12-INCH SEWER  (7  of  17)
Obser-
vation
No.





289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
Maximum
Flush
Wave
Depth

-W_-
D
(in.)
5. 0
3. 5
3. 5
4. 3
5.0
3.0
3. 5
3. 5
9.0
7. 5
7.0
6. 5
5. 0
4. 0
3.8
4.3
6.0
5.0
4. 5
5. 5
4. 0
3. 5
3. 5
3. 8
8. 0
6. 5
5. 8
6. 5
4. 5
3. 5
3.3
4.0
5.8
4.8
4. 5
5.3
6. 5
5. 5
5. 0
5. 5
7. 3
6.0
5. 5
5. 5
5.3
4.3
3. 8
4. 3
Distance
Down-
stream
of Flush
Release


(ft)
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
Pipe
Slope



-So-


. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 004
.004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
.004
.004
.004
.004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
Sewage
Base
Flow


-Q
B
(gpm)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
Flush
Rate



-Q
F
(gpm)
1617
1617
1617
1617
1347
1347
1347
1347
1911
1911
1911
1911
1568
1568
1568
1568
294
294
294
294
196
196
196
196
1862
1862
1862
1862
1225
1225
1225
1225
245
245
245
245
980
980
980
980
882
882
882
882
1519
1519
1519
1519
Flush
Volume



-V
F
(gal.)
300
300
300
300
300
300
300
300
900
900
900
900 ;
300 -
300 ;
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
                             121

-------
Table 9   SUMMARY  OF MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED IN 12-INCH SEWER (8 of 12)
Obser-
vation
No.




337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
Maximum
Flush
Wave
Depth

-WD-
(in. )
4.8
3.3
3. 8
4.0
7.0
8. 0
7.8
7. 0
5. 0
4.0
3. 5
4.0
4.8
4. 3
4. 5
4.8
4.0
2. 5
3.3
3.8
8.0
7.3
7. 0
6.8
4.8
4. 0
4. b
4. 3
3.8
3. 5
3.3
3. 5
4.8
4. 5
4. 8
5.0
5. 0
4.0
4. 3
4. 0
8.5
7. 5
8. 0
6.8
5. 3
4. 5
4. 5
4. 5
Distance
Down -
stream
of Flush
Release

(ft)
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
361
442
473
535
Pipe
Slope



-So-

. 004
. 004
. 004
. 004
. 006
. 006
.006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
.006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
.006
.006
. 006
.006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
Sewage
Base
Flow


-QB-
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
10
10
10
10
10
10
10
10
Flush
Rate



-QF-
(gpm)
1475
1475
1475
1475
1960
1960
I960
I960
1470
1470
1470
1470
294
294
294
294
220
220
220
220
1911
1911
1911
1911
1176
1176
1176
1176
196
196
196
196 ;
245
245
245
245
1323
1323
1323
1323
1764
1764
1764 ,
1764
1323
1323
1323
1323
Flush
Volume



-v
(gal. )
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
                           122

-------
Table 9   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED IN 12-INCH SEWER  (9 of 12)
Obser-
vation
No.




,
385
3&6
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
Maximum
Flush
Wave
Depth

-•w
D
(in.)
6.0
5. 7
5.6
5. 1
6.3
6.0
6.0
6.0
5.5
5.8
5.8
5.8
4.9
5.0
4.8
4.9
5. 3
5.0
5.3
5.3
5. 0
5. 0
5.0
3.3
3. 5
3. 5
3. 5
2. 8
4. 3
4. 3
4.0
4. 5
4.3
4.3
4.3
4.3
5.5
5.0
4.8
5. 0
5. 0
5.0
4.8
4.5
3.0
3. 1
3. 5
3.6
Distance
Down-
stream
of Flush
Release


(ft)
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
Pipe
Slope



-So-


.002
.002
. 002
. 002
. 002
. 002
.002
.002
. 002
. 002
. 002
.002
.002
. 002
.002
.002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
.002
.002
. 002
. 002
. 002
. 002
. 002
.002
.002
.002
.002
. 002
. 002
.002
.002
. 002
.002
. 002
. 002
.002
Sewage
Base
Flow


-Q -
B
(gpm)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
20
20
20
20
20
20
20
20
10
10
10
10
Flush
Rate



-Q_
F
(gpm)
1267
1267
1267
1267
1911
1911
1911
1911
323
323
323
323
294
294
294
294
1029
1029
1029
1029
1878
1878
1878
1878
196
196
196
196
679
679
679
679
1580
1580
1580
1580
2096
2096
2096
2096
294
294
294
294
1102
1102
1102
1102
Flush
Volume



-V
F
(gal.)
900
900
900
900
900
900
900
900
900
900
900
900
600
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
                              123

-------
Table 9   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED IN 12-INCH SEWER (10 of 12)
Obser-
vation
No.
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
Maximum
Flush
Wave
Depth
-WD-
(in.)
4.8
5. 0
4.8
4.8
5.8
5. 5
5.4
5. 8
5. 3
5.0
5. 0
5. 1
6. 1
6.0
6.3
6.3
4. 0
4. 0
3. 5
3.0
5. 5
5. 5
5. 5
5. 5
5. 0
5. 3
5. 1
5. 3
4. 1
4. 5
4. 5
4.8
2.8
2.9
3. 0
3. 1
4. 8
4.6
4. 8
4. 8
4. 8
5. 0
4. 8
4.8
4. 3
4. 5
4. 0
4.8
Distance
Down-
stream
of Flush
Release
(ft)
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
Pipe
Slope
-So-
. 002
. 002
. 002
. 002
.002
. 002
.002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. OOZ
.002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
.002
. 002
. 002
. 002
. 002
. 002
. 002
.002
. 002
.002
.002
.002
.002
.002
Sewage
Base
Flow
-QB-
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
10
10
10
10
30
30
30
30
30
30
30
30
10
10
10
10
20
20
20
20
20
20
20
20
20
20
20
20
Flush
Rate
-QF-
(gpm)
1078
1078
1078
1078
2058
2058
2058
2058
245
245
245
245
1176
1176
1176
1176
698
698
698
698
1127
1127
1127
1127
1065
1065
1065
1065
238
238
238
238
226
226
226
226
1543
1543
1543
1543
1065
1065
1065 •
1065
257
257
257
257
Flush
Volume
-v
(gal. )
600
600
600
600
900
900
900
900
900
900
900
900
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
600
600
600
600
600
600
600
600
600
600
600
600
                              124

-------
Table 9   SUMMARY OF MAXIMUM  FLUSH WAVE DEPTHS
          OBSERVED IN 12-INCH SEWER  (11  of  12)
Obser-
vation
No.





481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
Maximum
Flush
Wave
Depth

-Wr^
D
(in.)
4.0
4. 0
4.3
4. 3
3.8
3. 5
3. 5
4. 0
6.0
6. 5
7. 0
6.8
4. 3
4.3
4.3
4. 0
5. 8
5.8
5. 5
5. 8
3. 8
3.8
3. 8
3. 5
6.3
6.3
6. 5
6.0
4. 0
3. 8
3. 8
3. 5
5.5
5.5
5.5
5.3
5. 0
5. 5
5. 3
5.3
5. 5
5.3
5.8
5. 5
4. 5
4. 5
4. 5
4. 3
Distance
Down-
stream
of Flush
Release


(ft)
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
Pipe
Slope



-So-


. 002
.002
.002
. 002
. 002
. 002
. 002
. 002
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
.004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
Sewage
Base
Flow


-Q -
B
(gpm)
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
Flush
Rate



-Q -
F
(gpm)
1617
1617
1617
1617
1347
1347
1347
1347
1911
1911
1911
1911
1568
1568
1568
1568
294
294
294
294
196
196
196
196
1862
1862
1862
1862
1225
1225
1225
1225
245
245
245
245
980
980
980
980
882
882
882
882
1519
1519
1519
1519
Flush
Volume



-V -
F
(gal.)
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
                              125

-------
Table 9   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
          OBSERVED  IN 12-INCH SEWER (12 of 12)
Obser-
vation
No.





529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
Maximum
Flush
Wave
Depth

-W •
D
(in.)
4. 0
4. 0
4. 0
3.8
6.5
5.8
6. 5
6.0
4.0
4.0
4. 5
4.3
4.8
4. 5
5.8
4.8
3.8
3.5
3. 5
3. 3
6. 5
6.3
6.3
6.3
4. 3
4. 0
5. 0
4.8
3. 5
3. 3
3.8
3.8
5.0
4.8
5.8
5. 3
4. 0
4.3
4.3
4. 0
5. 5
6. 5
6. 5
6.5
4. 3
4. 3
4. 3
4. 0
Distance
Down-
stream
of Flush
Release


(ft)
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
614
680
732
770
Pipe
Slope



-So-


. 004
. 004
. 004
.004
. 006
. 006
. 006
. 006
. 006
. 006
.006
.006
.006
.006
.006
.006
.006
.006
. 006
. 006
. 006
. 006
. 006
. 006
.006
.006
. 006
. 006
. 006
.006
. 006
. 006
.006
.006
.006
.006
. 006
.006
.006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
. 006
.006
Sewage
Base
Flow


-QT>
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
10
10
10
10
10
10
10
10
Flush
Rate



-QTT-
F
(gpm)
2268
2268
2268
2268
1960
1960
I960
1960
1470
1470
1470
1470
294
294
294
294
220
220
220
220
1911
1911
1911
1911
1176
1176
1176
1176
196
196
196
196
245
245
245
245
1323
1323
1323
1323
1764
1764
1764
1764
1323
1323
1323
1323
Flush
Volume



-Vir-
F
(gal.)
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
                              126

-------
Table 10   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
           OBSERVED  IN 18-INCH SEWERS (1 of  12)
Obser-
vation
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Maximum
Flush
Wave
Depth
-WD-
(in. )
13. 0
11. 5
10. 0
8. 5
13.0
12.5
8.0
10. 0
6.8
6.8
5. 5
5. 5
6.0
6.5
5. 8
5.6
12.0
11.0
9. 5
6.8
15.5
11. 5
9.0
7.0
5. 8
5. 1
4.3
3. 8
7. 5
6.3
,5.5
'3.8
8.3
7. 5
5. 1
4. 0
13.0
12.0
12.0
11.0
12.0
13.0
13. 0
10. 0
7. 5
5.8
5. 5
4. 5
Distance
Down-
stream
of Flush
Release
(ft)
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope
-So-
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
.001
. 001
. 001
.001
.001
. 001
. 001
.001
.001
.001
.001
. 001
. 001
. 001
. 001
. 001
. 001
.001
.001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
.001
.001
.001
. 001
Sewage
Base
Flow
-QB-
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
50
50
50
50
Flush
Rate
-v
(gpm)
2131
2131
2131
2131
3381
3381
3381
3381
420
420
420
420
367
367
367
367
1470
1470
1470
1470
2021
2021
2021
2021
343
343
343
343
790
790
790
790
1212
1212
1212
1212
2572
2572
2572
2572
1960
I960
I960
I960
624
624
624
624
Flush
Volume
-VF
(gal. )
900
900
900
900
900
900
900
900
900
900
900
900
600
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
                             127

-------
Table 10   SUMMARY  OF MAXIMUM FLUSH WAVE DEPTHS
           OBSERVED IN 18-INCH SEWERS (2 of 12)
1 Obser-
vation
No.





49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
M aximum
Flush
Wave
Depth

-W -
D
(in.)
5. 3
5.0
4. 0
4. 3
8. 5
8. 5
7. 1
7. 0
6.8
6.6
5. 6
5.6
6.3
6.0
5. 0
4.8
5. 1
4. 5
3. 5
2.8
18. 0
14. 0
12. 0
10. 0
15. 0
11.0
8. 5
6. 5
11.0
7. 1
5. 9
4. 1
13. 0
10. 0
7.3
5. 8
14. 0
14. 0
11.0
8. 8
8.9
8.4
7.0
6. 5
12.0
7. 5
7. 3
7. 0
Distance
Down-
stream
of Flush
Release


(ft)
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope



-So-


. 001
. 001
. 001
. 001
. 001
.001
. 001
.001
. 001
. 001
. 001
.001
.001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
.001
.001
. 001
.001
. 001
. 001
.001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
Sewage
Base
Flow


-QD
B
(gpm)
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
50
50
50
50
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
Flush
Rate



-QTT
F
(gP*n)
269
269
269
269
759
759
759
759
441
441
441
441
385
385
385
385
330
330
330
330
3234
3234
3234
3234
2499
2499
2499
2499
1323
1323
1323
1323
1506
1506
1506
1506
1947
1947
1947
1947
1029
1029
1029
1029
1764
1764
1764
1764
Flush
Volume



-V -
F
(gai.) ;
, 300
300
300
300
900 :
900
900
900
900
900
900
900 '
600
600
600
600
300
300 ;
300
300
900
900
900
900
600
600
600
600
300
300
300
300
300
300
300
300
900
900
900
900
600
600
600
600
300
300
300
300
                             128

-------
Table 10   SUMMARY OF MAXIMUM FLUSH WAVE  DEPTHS
           OBSERVED IN  18-INCH  SEWERS (3  of 12)
Obser-
vation
No.





97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
HZ
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
Maximum
Flush
Wave
Depth

-W -
D
(in.)
12.0
9.0
6.0
4. 5
7.0
7.0
5. 3
5. 3
11.0
8. 5
8.3
8. 5
8. 5
6.5
5.3
4. 5
6.8
6.0
5. 8
5.8
5.3
4. 5
4.3
3. 8
13.0
13. 0
13.0
9.0
9.5
8. 5
8.0
6.0
6. 5
6.0
5. 5
5. 5
8.0
6. 5
6. 5
6.3
7. 0
7. 0
6.5
6.3
7. 5
7.0
6.0
4. 8
Distance
Down-
stream
of Flush
Release


(ft)
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope



-So-


. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
.002
.002
. 002
. 002
. 002
. 002
. 002
. 002
.002
.002
. 002
.002
.002
. 002
. 002
. 002
.002
. 002
. 002
.002
.002
.002
. 002
.002
. 002
. 002
. 002
. 002
.002
.002
.002
.002
.002
.002
. 002
.002
.002
.002
.002
. 002
Sewage
Base
Flow


-QT,
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
Flush
Rate



-QT.
F
(gpm)
1690
1690
1690
1690
710
710
710
710
2940
2940
2940
2940
1323
1323
1323
1323
441
441
441
441
343
343
343
343
2989
2989
2989
2989
1127
1127
1127
1127
441
441
441
441
882
882
882
882
980
980
980
980
931
931
931
931
Flush
Volume



-V_
F
(gal.)
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
                             129

-------
Table 10   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
           OBSERVED IN 18-INCH SEWERS (4 of 12)
Obser-
vation
No.




145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
Maximum
Flush
Wave
Depth

-WD
(in.)
7.5
6.5
6.0
4. 5
18. 0
16. 0
10. 5
11. 0
13.0
5.3
6.3
5. 5
6.0
5. 5
5. 8
6.0
7. 5
6.0
5.3
4. 5
13.0
7. 0
11. 0
6.0
7. 5
6. 0
6.0
5. 0
4. 5
4. 5
4. 3
4. 3
6. 5
4. 3
4. 3
4. 5
7.3
6.0
5. 5
5. 0
8.8
8.0
9.0
7. 5
10. 5
7. 5
6. 5
4. 5
Distance
Down-
stream
of Flush
Release

(ft)
92
164
218
290
92
164 .
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
92
164
218
290
Pipe
Slope



-So-

. 002
. 002
.002
. 002
. 004
.004
. 004
. 004
.004
.004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
Sewage
Base
Flow


-QB
(gpm)
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
Flush
Rate



-QF-
(gpm)
931
931
931
931
2989
2989
2989
2989
1911
1911
1911
1911
490
490
490
490
98
98
98
98
2450
2450
2450
2450
1470
1470
1470
1470
343
343
343
343
196
196
196
196
784
784
784
784
1176
1176
1176
1176
1617
1617
1617
1617
Flush
Volume



-v
(gal. )
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
                             130

-------
fable 10   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
           OBSERVED IN 18-INCH SEWER (5 of 12)
Obser-
vation
No.





1*3
194
195
196
197
198
199
ZOO
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
Maximum
Flush
Wave
Depth

-w -
D
(in.)
7.0
4.8
4. 5
4.8
8.5
5.3
5.8
5. 0
5.0
4. 8
4. 5
4.4
5.6
3.5
5. 5
5.0
5. 3
3.8
4.0
3. 8
5. 5
4.0
3.8
3. 5
3. 5
3. 0
3. 0
2. 8
3. 5
3. 0
2. 5
2. 8
3.0
3. 0
3.3
2.6
8.8
7. 5
7.3
7. 0
7.6
5. 5
6.0
5. 5
4. 0
3. 0
3. 5
3. 5
Distance
Down-
stream
of Flush
Release


(ft)
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
Pipe
Slope



-So-


. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
.001
.001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
.001
. 001
. 001
. 001
.001
. 001
.001
. 001
. 001
. 001
. 001
.001
.001
.001
. 001
. 001
. 001
Sewage
Base
Flow


-QT,
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
50.
50
50
50
Flush
Rate



-Q -
F
(gpm)
2131
2131
2131
2131
3381
3381
3381
3381
420
420
420
420
367
367
367
367
1470
1470
1470
1470
2021
2021
2021
2021
343
343
343
343
790
790
790
790
1212
1212
1212
1212
2572
2572
2572
2572
I960
I960
I960
I960
624
624
624
624
Flush
Volume



-V -
F
(gal.)
900
900
900
900
900
900
900
900
900
900
900
900
600
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
                            131

-------
Table 10   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
           OBSERVED IN 18-INCH SEWERS (6 of 12)
Obser-
vation
No.





241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
Maximum
Flush
Wave
Depth

Tir
D"
(in.)
3.8
3. 5
3. 5
3. 5
6.3
5.5
5.8
5.4
5.3
5. 5
5. 1
5.0
4.0
4.0
3.8
3.4
2.5
2.8
2. 5
2. 3
7. 5
6.0
6.0
5.6
5. 0
4. 3
4. 0
3. 6
3. 3
3. 3
3. 1
2. 3
5. 0
4. 5
4. 0
3.3
7.0
6.0
5. 8
5.4
5. 5
4.9
4. 8
4. 3
5.0
2.8
4.3
3. 5
Distance
Down-
stream
of Flush
Release


(ft)
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
Pipe
Slope



-So-


. 001
. 001
.001
.001
.001
.001
. 001
.001
. 001
.001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
.001
.001
. 001
.001
.001
.001
.001
. 001
.001
.001
. 001
. 001
. 001
. 001
. 001
.001
.001
.001
.001
Sewage
Base
Flow


Q
B
(gpm)
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
50
50
50
50
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
Flush
Rate



-Q
F
(gpm)
269
269
269
269
759
759
759
759
441
441
441
441
385
385
385
385
330
330
330
330
3234
3234
3234
3234
2499
2499
2499
2499
1323
1323
1323
1323
1506
1506
1506
1506
1947
1947
1947
1947
1029
1029
1029
1029
1764
1764
1764
1764
Flush
Volume



y
F
(gal.)
300
300
300
300
900
900
900
900
900
900
900
900
600
600
600
600
300
300
300
300
900
900
900
900
600
600
600
600
300
300
300
300
300
300
300
300
900
900
900
900
600
600
600
600
300
300
300
300
                             132

-------
Table 10   SUMMARY  OF MAXIMUM FLUSH  WAVE  DEPTHS
           OBSERVED  IN 18-INCH SEWERS  (7  of  12)
Obser-
vation
No.
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
Maximum
Flush
Wave
Depth
-WD-
(in. )
3. 5
3. 0
3. 3
2. 8
3. 5
2. 5
2. 5
2. 5
7. 3
5. 0
5. 0
5. 3
3. 5
3.3
3. 3
3.0
5.8
5. 0
5. 0
5.0
3. 5
3. 0
2. 0
3. 3
7. 3
4. 8
4.0
5.0
5. 5
4.8
4.3
4. 5
5.3
4.8
4. 8
4. 5
5. 5
4. 8
4. 3
4. 5
5. 3
4. 0
3.8
4. 3
3. 5
3. 5
3. 0
3. 3
Distance
Down-
stream
of Flush
Release
(ft)
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
Pipe
Slope
-So-
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
. 002
Sewage
Base
Flow
-QB
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
Flush
Rate
-QF
(gpm)
1690
1690
1690
1690
710
710
710
710
2940
2940
2940
2940
1323
1323
1323
1323
441
441
441
441
343
343
343
343
2989
2989
2989
2989
1127
1127
1127
1127
441
441
441
441
882
882
882
882
980
980
980
980
931
931
931
931
Flush
Volume
-VF
(gal.)
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
                              133

-------
Table 10   SUMMARY OF MAXIMUM FLUSH WAVE DEPTHS
           OBSERVED IN 18-INCH SEWERS (8  of  12)
Obser-
vation
No.





337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
Maximum
Flush
Wave
Depth

-W -
D
(in.)
4.0
3. 5
2. 5
3.8
9.0
7.0
7. 0
6. 5
4. 5
3. 8
3. 5
4. 0
5. 3
5. 3
5. 0
6. 0
4. 3
2. 5
3. 5
3.8
5. 5
5. 3
5.8
6.0
4.3
3. 5
2. 5
3.8
3. 5
2. 8
3. 3
3. 3
4. 5
4. 0
4. 3
4.8
4. 3
3.8
3. 3
2. 5
7. 0
4. 5
6. 5
5. 5
4. 8
4. 0
2. 5
4. 0
Distance
Down-
stream
of Flush
Release


(ft)
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
361
432
490
548
Pipe
Slope



-So-


. 002
. 002
.002
. 002
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
Sewage
Base
Flow


-c> -
B
(gpm)
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
Flush
Rate



-OTT
F
(gpm)
931
931
931
931
2989
2989
2989
2989
1911
1911
1911
1911
490
490
490
490
98
98
98
98
2450
2450
2450
2450
1470
1470
1470
1470
343
343
343
343
196
196
196
196
784
784
784
784
1176
1176
1176
1176
1617
1617
1617
1617
Flush
Volume



-VTT
F
(gal.)
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
                             134

-------
Table 10   SUMMARY OF  MAXIMUM FLUSH  WAVE DEPTHS
           OBSERVED  IN  18-INCH SEWERS (9  of  12)
Obser-
vation
No.





385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
Maximum
Flush
Wave
Depth

-W_,-
D
(in.)
4. 3
4. 0
3. 8
3.8
4. 8
4. 5
4. 3
3.8
4. 1
4.0
3.9
3.8
4.8
4. 8
4. 5
3.9
3.5
3.4
3. 3
3.3
3.4
3. 3
3. 0
3.0
2. 8
2. 5
2. 5
2. 5
2. 5
2. 3
2. 0
2. 5
2. 3
2. 3
2. 0
2.3
5. 8
6.0
5. 3
4. 3
4.8
4.6
4.4
4. 0
3. 1
3. 0
3. 0
3. 0
Distance
Down-
stream
of Flush
Release


(ft)
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
Pipe
Slope



-So-


. 001
. 001
.001
.001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
Sewage
Base
Flow


-Q
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
50
50
50
50
Flush
Rate



-Q
F
(gpm)
2131
2131
2131
2131
3381
3381
3381
3381
420
420
420
420
367
367
367
367
1470
1470
1470
1470
2021
2021
2021
2021
343
343
343
343
790
790
790
790
1212
1212
1212
1212
2572
2572
2572
2572
I960
I960
I960
I960
624
624
624
624
Flush
Volume



-V -
F
(gal.)
900
900
900
900
900
900
900
900
900
900
900
900
600
600
600
600
600
600
600
600
600
600
600
600
300
300
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
                             135

-------
Table 10   SUMMARY OF  MAXIMUM  FLUSH WAVE DEPTHS
           OBSERVED IN  18-INCH  SEWERS  (10 of 12)
Obser-
-vation
No.





433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
Maximum
Flush
Wave
Depth

-W -
D
(in. )
3. 3
3. 1
3. 3
3. 1
4.8
4. 5
4.3
4. 0
4. 5
4. 5
4. 5
4. 0
3.0
3.0
3.0
3. 0
2.0
2.0
2. 0
2. 0
5. 0
4. 8
4. 5
4.4
3. 3
3. 3
3. 0
3. 3
2. 3
2. 3
2. 3
2. 5
3. 3
2.4
2.4
3. 3
4.8
4.8
4.4
4. 0
4. 0
4. 0
3. 3
3. 5
3. 0
2. 0
2. 0
2. 8
Distance
Down-
stream
of Flush
Release


(ft)
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
Pipe
Slope



-So-


. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
.001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
. 001
.001
. 001
. 001
. 001
. 001
. 001
Sewage
Base
Flow


-QT,-
B
(gpm)
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
50
50
50
50
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
Flush
Rate



-QTT-
F
(gpm)
269
269
269
269
759
759
759
759
441
441
441
441
385
385
385
385
330
330
330
330
3234
3234
3234
3234
2499
2499
2499
2499
1323
1323
1323
1323
1506
1506
1506
1506
1947
1947
1947
1947
1029
1029
1029
1029
1764
1764
1764
1764
Flush
Volume



-V -
F
(gal.)
300
300
300
300
900
900
900
900
900
900
900
900
600
600
600
600
300
300
300
300
900
900
900
900
600
600
600
600
300
300
300
300
300
300
300
300
900
900
900
900
600
600
600
600
300
300
300
300
                             136

-------
Table 10   SUMMARY OF  MAXIMUM FLUSH  WAVE DEPTHS
           OBSERVED IN  18-INCH SEWERS (11 of 12)
Obser-
vation
No.





481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
Maximum
Flush
Wave
Depth

-wr>-
D
(in.)
2.8
2.8
2. 5
2. 5
2. 5
2. 5
2.3
2.3
4.8
4.8
4.5
4. 5
3.0
2.8
2.8
2.8
4. 5
4. 5
4. 3
3.8
2.8
2.8
3. 0
2.8
4.8
4.5
4. 5
4. 0
3.8
4.3
4.3
3.8
4. 3
4.3
4.3
3.8
4.3
4. 0
4.0
4.0
3. 8
3.8
3.8
3.8
3.0
2.8
2.8
3.0
Distance
Down-
stream
of Flush
Release


(ft)
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
Pipe
Slope



-So-


. 001
.001
.001
.001
. 001
. 001
. 001
. 001
.002
. 002
.002
. 002
. 002
. 002
. 002
. 002
.002
.002
.002
. 002
. 002
.002
.002
. 002
. 002
.002
. 002
.002
.002
.002
. 002
.002
. 002
. 002
. 002
. 002
.002
. 002
.002
.002
.002
.002
. 002
. 002
. 002
.002
.002
.002
Sewage
Base
Flow


-Q -
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
Flush
Rate



-Q_
F
(gpm)
1690
1690
1690
1690
710
710
710
710
2940
2940
2940
2940
1323
1323
1323
1323
441
441
441
441
343
343
343
343
2989
2989
2989
2989
1127
1127
1127
1127
441
441
441
441
882
882
882
882
980
980
980
980
931
931
931
931
Flush
Volume



V -
F
(gal.)
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
600
600
600
600
600
600
600
600
300
300
300
300
                            137

-------
Table 10   SUMMARY OF MAXIMUM  FLUSH WAVE DEPTHS
           OBSERVED IN 18-INCH SEWERS  (12 of 12)
Obser-
vation
No.
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
Maximum
Flush
Wave
Depth
-WD
(in.)
3.8
3.0
3.3
' 3.0
5. 5
5. 5
5. 5
5. 5
3. 5
3. 5
3. 5
3. 3
5.0
4.8
5.0
4. 8
3. 5
3. 5
3. 5
3.3
4. 8
4. 8
4. 8
4. 5
3.3
3. 5
3. 5
3. 3
3.0
2.8
2.8
2.8
4. 5
4.0
4. 3
4. 0
3. 3
3. 3
3.3
3. 3
5.5
4.8
5.0
4.5
3.8
3. 8
3. 5
3. 5
Distance
Down-
stream
of Flush
Release
(ft)
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
614
691
744
780
Pipe
Slope
-So-
. 002
.002
.002
.002
.004
. 004
. 004 .
. 004
. 004
. 004
. 004
.004
.004
.004
. 004
.004
.004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
.004
.004
. 004
. 004
. 004
. 004
. 004
.004
.004
. 004
. 004
. 004
. 004
. 004
.004
.004
. 004
. 004
. 004
.004
.004
. 004
Sewage
Base
Flow
-QB
(gpm)
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
50
50
50
50
50
50
50
50
Flush
Rate
-QF
(gpm)
931
931
931
931
2989
2989
2989
2989
1911
1911
1911
1911
490
490
490
490
98
98
98
98
2450
2450
2450
2450
1470
1470
1470
1470
343
343
343
343
196
196
196
196
784
784
784
784
1176
1176
1176
1176
1617
1617
1617
1617
Flush
Volume
-VF
(gal.)
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
300
300
300
300
900
900
900
900
300
300
300
300
                             138

-------
                 Table 11    SUMMARY OF  STEEP-SLOPE EQUATION VERIFICATION
Pipe
Diam-
eter
-D-

(in. )
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
Pipe
Slope

-So-


.008
.008
. 008
.008
. 008
. 008
. 008
.008
.008
. 008
. 008
. 008
. 008
. 008
.008
.008
Flush
Rate

~QF~

(gpm)
1421
1421
1421
1421
1715
1715
1715
1715
1813
1813
1813
1813
1372
1372
1372
1372
Flush
Volume

-VF-

(gal. )
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
Pipe
Length

-L-

(ft)
267
514
622
782
267
514
622
782
267
514
622
782
267
514
622
782
Sewage
Base
Flow
-Q-

(gpm)
10
10
10
10
10
10
10
10
30
30
30
30
30
30
30
30
SS Clean Effluent
-C" - (%)

©
Observed
Value
94. 1
87. 2
87. 5
73. 5
98. 0
98. 5
93. 5
91. 8
98. 0
90.9
80. 0
76.4
86.3
68. 3
67. 0
63.9
CD
Estimated
Value
97.4
86.2
82.9
76.3
100.0
100. 0
98.3
94.4
100.0
90. 0 ^
86.7 "
82.8
82.9
71. 7
68.4
64.5
VSS Clean Effluent
-C" - (%)

©
Observed
Value
93.9
88. 8
80.0
71.4
97. 1
93.4
89. 3
86.3
94. 1
89. 1
86. 5
82. 2
84.9
74.0
70. 5
66.2
(D
Estimated
Value
97. 5
87.6
84. 7
76. 2
100. 0
100. 0
100.0
96.5
100. 0
90.9
88. 0
84. 6
84.7
74.8
71. 9
68.4
TOC Clean Effluent
-C" - (%)

©
Observed
Value
71.3
72.3
47.0
46.7
53.9
54. 2
32. 1
39.6
79.7
53.3
54. 8
55.0
65. 5
62.2
58. 0
56.0
(D
Estimated
Value
68.8
64. 1
62.7 '
61. 1
75.2
70. 5
69. 1
67. 5
70.4
65.7
64.3
62.7
62.7
58. 0
56.7
55. 0
NOTES:  (l)   Observed values were taken from test data, Tests 123  through 126.
         @   Estimated values were taken from Equation No.  10.
         @   Observed values -were taken from Equation No. 11.
         @   Estimated values were taken from Equation No.  12.

-------
           Table 12    STEEP-SLOPE  CHECK  OF WAVE DEPTH EQUATION (Equation 13A)
Pipe
Diameter
-D-
(in. )
12©
12©
12©
12©
12©
12©
12©
12©
Pipe
Slope
-So-
. 008
.008
.008
.008
.008
.008
.008
. 008
Flush
Rate
-QF-
(gpm)
1715
1715
1421
1421
1813
1813
1372
1372
Flush
Volume
-v
(gal.)
900
900
300
300
900
900
300
300
Sewage
Base
Flow
-QB-
(gpm)
10
10
10
10
30
30
30
30
Flush Wave Depth
At Various Locations From Influent End
(inches)
92'
12.00
10.67
9. 50
9.30
10. 50
11. 68
9.25
9.76
164'
9. 50
9.83
8.25
8.46
10. 50
10. 84
8.85
8.92
218'
9.00
. 9.32
7. 25
7.95
10. 50
10.33
7.95
8.41
290'
8. 50
8.73
7. 50
7.36
9. 50
9.74
7.25
7.82
361'
8. 50
8. 21
6.00
6.84
9.00
9.22
7.00
7.30
442'
7. 75
7.68
5. 50
6.31
9. 50
8.69
6.25
6.77
473'
8.25
7.49
5.75
6. 12
8.25
8. 50
5.75
6. 58
535'
6. 50
7. 13
5.00
5.76
8.00
8. 14
5.75
6.22
614'
7. 50
6.70
5.25
5.33
8.25
7.71
5.50
5.79
680'
7. 50
6.36
5.00
4.99
7.50
7.37
.5.25
5.45
732'
6.00
6.11
5.00
4.74
7. 50
7. 12
5.25
5.20
770'
5.25
5.93
4.75
4.56
7.50
6.94
5.00
5.02
NOTES: ©   Observed Values were taken from test data, Tests 123, 124,  125 and 127.
        @   Estimated values determined using Equation No.  13A.

-------
     Table 13    RESULTS  FROM SEWAGE FLUSH  CORRELATION
                                   TESTS  (1 of 2)
Observation
No.






1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Predicted ®
Clean-Water
Cleansing
Efficiency

-^cc-
ESS
(%)
68.9
57.6
54.4
50.4
85.4
74. 2
70.9
67.0
84.2
72.9
69.7
65.7
100. 0
93.4
90. 1
86. 2
67.6
56.4
53. 1
49.2
86.0
74. 8
71. 5
67.6
85.2
74. 0
70.7
66.8
100. 0
94.0
90. 8
86. 8
100. 0
93.7
90.4
86. 5
83.6
72.4
69. 1
65.2
85.6
74.4
Observed
Sewage
Flush
Cleansing
Efficiency

-C '-
ESS
(%)
70.9
53.9
44.2
41. 8
79.3
79.3
73.9
63. 5
86.3
74.7
72.6
62.6
89.9
85. 0
79.9
70. 5
65.7
56. 0
53.4
46.2
79.7
68.4
65.0
54.3
86.4
73.2
67. 5
59.9
94.2
88.4
83. 1
71.4
91.9
86. 5
84. 0
74.3
50.7
43.6
41.9
32.9
68.3
61.6
Percent ®
Reduction
In Cj-gg
Resulting
From Sewage
Flush
- AC"
ESS
(%)
2.90
+ 6.42
+ 18.75
+17.06
+ 7. 14
6.87
4.23
+ 5.22
2.49
2.47
4. 16
+ 4.72
+ 10. 10
+ 8.99
+11.32
+ 18.21
+ 2.81
+00: 71
0. 56
+ 6. 10
+ 7.33
+ 8.56
+ 9.09
+ 19.67
1.41
+ 1.08
+ 4. 53
+10.33
+ 5. 80
+ 5.96
+ 8.48
+17.74
+ 8. 10
+ 7.68
+ 7. 08
+14. 10
+39.35
+39.78
+39.36
+45. 54
+20.21
+17. 20
Length
of
Sewer
Flushed

-L-

(ft)
267
514
622
782
267
514
622
782
267
514
622
782
267
514
622
782
267
514
622
782
267
514
622
782
267
514
622
782
267
514
62Z
782
267
514
622
782
267
514
622
782
267
514
Flush
Rate



-Q -
F
(gpm)
220
220
220
220
1225
1225
1225
1225
220
220
220
220
1838
1838
1838
1838
194
194
194
194
1298
1298
1298
1298
245
245
245
245
1960
1960
1960
1960
1886
1886
1886
1886
208
208
208
208
1250
1250
Flush
Volume



-V -
F
(gals.)
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
900
900
900
900
900
900
900
900
300
300
Pipe
Slope



-So-


.004
.004
. 004
. 004
.004
.004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
.004
. 004
. 004
.004
. 004
.004
. 004
. 004
. 004
. 004
. 004
. 004
. 004
.004
.004
. 004
. 004
.004
.004
.004
.004
.004
.004
.004
.004
.004
Sewage
Base
Flow


-Q -
B
(gpm)
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
Pipe
Diameter



-D-

(in. )
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
NOTES:
          Computed using Equation 10.
          Computed using Equation 15.
                                             141

-------
      Table  13    RESULTS FROM SEWAGE  FLUSH  CORRELATION
                                   TESTS (2 of 2)
Obse rvation
No.






43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
Predicted®
Clean-Water
Cleansing
Efficiency

J~
"CESS
(%)
71. 1
67. 2
47. 6
45.9
32.7
28.8
61.3
49.7
46. 5
42.6
62. 8
51. 1
47. 9
44. 1
82.8
71. 1
67.9
64. 1
47. 1
35. 5
32. 3
28.4
61.3
49.7
46. 5
42.6
65.2
53. 5
50.3
46. 5
86; 4
74. 8
71. 6
67.7
64. 1
52.4
49.2
45.4
60. 5
48.8
45. 6
41.8
Observed
Sewage
Flush
Cleansing
Efficiency

"c '
ESS
(%)
56. 0
52.2
56. 0
42.2
37. 8
32.3
70. 1
70. 2
64.2
55. 1
62. 5
64. 1
53.7
41. 2
83.5
59.2
46.6
30.4
33. 3
32.0
24.9
18. 5
75.3
75. 5
65. 5
56.2
61. 8
56.7
51. 5
45. 6
89.7
76.3
71.0
63.7
67.3
63. 8
61.6
58.4
76.7
64.9
59.6
53. 2
Percent ®
Reduction
In CESS
Resulting
From Sewage
Flush
- AC
ESS
(%)
+21.24
+22.32
-17.65
+ 8.06
-15.60
-12. 15
-14.36
-41.25
-38.06
-29.34
+ 0.48
-25.44
-12. 11
+ 6. 58
0.85
+ 16.74
+31.37
+52.57
+29. 30
+ 9.86
+ 22.91
+34.86
-22. 84
-51.91
-40.86
-31.92
t 5.21
5.98
2.39
+ 1.94
3.82
2.01
+ 0.84
+ 5.91
4.99
-21. 76
-25.20
-28.63
-26. 78
-34.09
-30.70
-27.27
Length
of
Sewer
Flushed

-L-

(ft)
622
782
267
527
635
795
267
527
635
795
267
527
635
795
267
527
635
795
267
527
635
795
267
527
635
795
267
527
635
795
267
527
635
795
267
527
635
795
267
527
635
795
Flush
Rate



-Q -
F
(gpm)
1250
1250
270
270
270
270
1127
1127
1127
1127
268
268
268
268
2132
2132
2132
2132
258
258
258
258
1127
1127
1127
1127
343
343
343
343
3112
3112
3112
3112
306
306
306
306
1029
1029
1029
1029
Flush
Volume



-V -
F
(gals.)
300
300
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
300
300
300
300
300
300
300
300
900
900
900
900
900
900
900
900
900
900
900
900
300
300
300
300
Pipe
Slope



-So-


.004
.004
.002
.002
.002
.002
.002
.002
. 002
.002
. 002
. 002
.002
.002
.002
.002
.002
.002
. 002
.002
. 002
.002
.002
. 002
.002
.002
.002
.002
.002
.002
.002
.002
.002
.002
.OOZ
.002
. OOZ
.002
.002
.002
. 002
. 002
Sewage
Base
Flow


-Q -
B
(gpm)
10
10
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
Pipe
Diameter



-D-

(in. )
12
12
18
18
is
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
18
NOTES:
          Computed using Equation 10.
          Computed using Equation 15.
                                          142

-------
         Table  14     RESULTS  FROM PIPE MISALINEMENT  TESTS


Tests









Pipe
Misalinement








Grade
Misalinement


Pipe
Diameter


-D-
(in. )
©
12 ^



1C.
12©
18©
18®
1 8
18©
12®
18®
12 ®


12©
18©
18®
18©
Pipe
Slope


-So-


. 004

. 004

.004
. 004
.002
. 002
.002
.002
. 004
. 002
. 004

.004
.004
. 002
. 002
.002
Sewage
Base
Flow

-QB-
(gpm)

10

10

10
10
50
50
50
50
10
50
10

10
10
50
50
50
Flush
Volume


-v
(gals. )

900

900

300
300
900
900
300
300
900
900
900

900
300
900
900
300
Flush
Rate


-Q -
(gpm)

1838

196

1372
208
2450
343
1127
270
1862
2254
1666

1666
1421
2303
I960
931
Average S. S. Cleansing Efficiency, C
(Percent) ESS

For the
First
267' of
Sewer

90.4

65. 5

79. 8
64.4
88. 5
42. 0
87.0
17.4
91. 2
89. 1
82.7

95.7
91.6
84. 1
96.6
70.4

For the
First
520' of
Sewer

85.4

65.4

72. 2
63. 1
82. 1
46. 0
57.0
15. 3
87.4
82.7
80.3

92.4
84.7
82.6
87. 0
58. 2

For the
First
630' of
Sewer

82. 5

64.0

69.0
60. 1
78.0
42. 5
50.7
8.6
84.0
78. 1
77.7

90.2
81.3
77.2
79.9
52. 1

For the
Full Length
of Sewer
(790')

76. 8

57.0

63.7
54.4
72. 8
38.5
44. 5
10. 9
78. 1
74. 5
74.2

86.2
73.9
73.6
74.6
44. 9
NOTES:   (I)   Six 1/2-inch steel rings at approximately 130-foot intervals, simulating pipe misalinement.
          ©   Three 1/2-inch steel rings at approximately 260-foot intervals, simulating pipe misalinement.
          ©   Six 1-inch steel rings at approximately 130-foot intervals, simulating pipe misalinement.
§               Three 1-inch steel rings at approximately 260-foot intervals, simulating pipe misalinement.
               Forty-three 1/2-inch grade misalinement at approximately 18-foot intervals.
               Forty-three 1-inch grade misalinement at approximately 18-foot intervals.
                                                    143

-------
                    Table  15     RESULTS  FROM FLUSH  WAVE  SEQUENCING  TESTS
Pipe
Diam -
e ter

-D-

(in. )
12
12
12
12
12
18
18
18
18
18
Pipe
Slope

-S -
o

. 004
. 004
. 004
. 004
. 004
. 002
. 002
. 002
. 002
. 002
Sewage
Base
Flow

-Q -
B
(gpm)
10
10
10
10
10
50
50
50
50
50
Average
Flush
Rate

-Q_-
F
(gPm)
230
1220
1370
150
1500
640
1200
1470
340
1620
Flush Volume
-v
(gal)

Tank
No. 1
300
300
900
600
600
300
300
900
600
600

Tank
No. 2
300
300
300


300
300
300



Tank

300
300
300
300
300
300
300
300
300
300
Values of C Observed at
JbjOo
the Various Sequences
~CESS~
(Ti
Flush Sequence ^^
A
57. 7
65. 8



44. 8
71.9



B
59.6
82. 2
80. 6
53. 5
73. 4
68. 2
74.6
75. 5
41. 8
61.6
C
62. 1
66.3



60.6
76.4



Equivalent ^
Single
Flush
Volume
-VP-
F
(gal)
600
600
1200
700
700
600
600
1200
700
700
SS Cleansing
Efficiency
Predicted
from


(%)
58. 8
76. 6
87. 5
63. 0
81. 0
46. 1
52.9
64.7
41. 5
58. 2
NOTES:  (I)   Flush Release Sequences:
              Sequence  A —  The flush tanks were activated separately beginning with the downstream flush tank (Tank No.  3).
              Sequence  B
              Sequence  C
The upstream flush tank (Tank No. 1) was activated first and then Tanks No. 2 and 3 were released,
when  the flush wave generated upstream reached its maximum depth at their respective positions.
The flush tanks were  activated separately, beginning with the upstream tank (Tank No.  1), so that
each of the three flush waves generated passed separately through the entire length  of the sewer.
              This parameter was determined by taking the summation of the products of the total quantity of water that passed
              through each of the three sections of pipe and the length of each section, and dividing by the total length of the sewer.

-------
                          Table 16
RESULTS FROM SOLIDS BUILDUP  TESTS
Ul
Pipe
Diam-

-D-

(in. )
12
12
12
18
18
18
Pipe
Slope

-S -
o


. 004
. 004
. 004
.002
. 002
. 002
Duration
of the
Flow
-DT-

(hrs)
42
94
188
42
94
188
Total SS Deposited
(Ibs)

In
First
267 ft
of
Pipe
1. 130
2. 560
4. 750
1. 270
3. 220
2. 330

In
First
520 ft
of
Pipe
1. 534
2. 975
5.470
3.350
8. 130
9.490

In
First
630 ft
of
Pipe
1. 695
3. 104
5.650
3.636
8.658
10. 100
In
Total
Length
of

Sewer,
790 ft
1.982
3.629
6. 590
3.988
8.993
10. 56
Total VSS Deposited
(Ibs)

In
First
267 ft
of
Pipe
0.832
1.420
2. 930
0. 640
1.375
0. 700

In
First
520 ft
of
Pipe
1. 130
1. 708
2. 920
2. 210
5. 075
4. 980

In
First
630 ft
of
Pipe
1. 184
1.798
3. 560
2. 380
5.517
5. 210
In
Total
Length
of

Sewer,
790 ft
1. 339
2. 208
0. 250
2. 573
5. 803
5.360
Total TOC Deposited
(Ibs)

In •
First
267 ft
of
Pipe
0. 149
0. 251
1.490
0. 206
0. 667
0.430

In
First
520 ft
of
Pipe
0. 253
0.368
1.580
0. 566
1.482
0. 770

In
First
630 ft
of
Pipe
0. 325
0. 533
1. 760
0. 672
1. 740
0. 930
In
Total
Length
of

Sewer,
790 ft
0.405
0.853
1. 760
0. 744
2. 040
0. 980

-------
Table 17   RESULTS  FROM PROTOTYPE FLUSH STATION TESTS
Station
Type
Fabric
Storage
Bag in
Manhole

In-line
Inflatable
Dam


Function
Evaluated
Fill Cycle
Dump Cycle
Lifting
Mechanism
Continuous
Operation
Inflatability
and
Installation
Rate of
Release
Flow
Interference
Solids
Removal
Findings
The pump was run for approximately 2 hours, at which time the bag was filled. Some
problems were experienced with clogging of the intake screen but were eliminated by
making it flatter.
The dump cycle was tested with the bag half full and completely full. The average
rate of discharge ranged from 800 gpm with the bag full to 670 gpm with the bag half
full.
The lifting mechanism was evaluated and found to function quite well. The bag was
lifted while void of water and was found to lift easily through a 20-inch opening.
The flush station was operated for 3 successive days and was found to perform very
dependably during this period. The control valve functioned very well and no major
clogging problems were experienced.
The bag was found to be easily inflated, once installed. However, the installation
was quite difficult because of the awkward design. It was noted that when the dam
is inserted directly into the sewer, it is hard to seal around and could possibly cause
problems with upstream flooding at the sewer.
The average release rate was found to be less than that which would be desirable
(ranging from approximately 500 to 1000 gpm depending on the degree of initial
inflation) due to air entrapment and slow deflation near the end of the cycle.
There was no evidence that the deflated dam produced any significant interference
with 'the normal sewage flows through the sewer.
Despite the low release rate, the flush wave downstream of the dam was visually
observed and found to remove much of the visable deposited material. However,
upstream of the dam, the solids deposits were very heavy and were not significantly
reduced after release of the stored sewage.

-------
                     APPENDIX D
   STATISTICAL ANALYSIS QF DESIGN EQUATIONS
Table 18   SUMMARY OF  STATISTICS FOR EQUATION 9
                  (SS CORRELATION)
Statistical
Parameter
Sum of the
Squares
Reduced
(of 228, 904)
Proportion
of Variance
of CESS
Reduced
F (DF=
1, 538)
Correlation
Coefficient
Regression
Coefficient
Standard
Error of
Regression
Coefficient
Computed
T for
Regression
Coefficient
Standard
Error of
Estimate
CESS
Intercept
Statistics For Each of the Independent Variables

-------
     Table 19   SUMMARY  OF  STATISTICS  FOR EQUATION 10
                           (SS Correlation)


STATISTICS  FOR  ALL 544-OBSERVED VALUES OF C

Proportion of Variance of C    Reduced	   0. 6414

Partial F (DF =  1, 542)	   969.4868
Cumulative Sum of Squares Reduced	   147691. 000
Cumulative Proportion Reduced	   0. 6414  (of
                                                        230258. 9000)
Multiple Correlation Coefficient	   0. 8060
F  For Analysis of  Variable  (DF =  1,542)	   969.4868
Standard Error of Estimate	   12. 1326

    .           Regression             Standard
Variable        r   ft-  •  ^         r     r   ft-  •   t.      Computed T
                Coefficient         Error-Coefficient

Log1Q(H)        24.0116               .771171             31.1366

Intercept (&-„„)  — 13.30284
             ESS


STATISTICS  AFTER DELETIONS OF 12 OBSERVATIONS (532)

Proportion of Variance of C    Reduced .	   0. 6847
Partial F  (DF =  1,530)	   1150.9930
Cumulative Sum of Squares Reduced	   148131. 7000
Cumulative Proportion Reduced	   0. 6847  (of
                                                        216342. 2000)
Multiple Correlation Coefficient	   0. 8275
F  For Analysis of Variable  (DF =  1,530)	   11.3446

»r   . ,  ,         Regression             Standard           _         „
Variable          6    .                         .          Computed T
                Coefficient         Error-Coefficient           ^

Log1()(H)        24.6802                .727465             33.9263

Intercept  (C~ CJ — 13.7134
                                148

-------
    Table  20   SUMMARY OF STATISTICS FOR  EQUATION  11
                          (VSS Correlation)
Proportion of Variance of C      Reduced	„   0. 5597
                           E Voo
Partial F (DF =  1, 530)	   673. 8613
Cumulative  Sum of Squares Reduced	   108994. 6000
Cumulative Proportion Reduced	   0. 5597  (of
                                                        194720.2000)
Multiple Correlation Coefficient	   0. 7482
F  For Analysis  of  Variable  (DF  =  1,530)	   673.8613
Standard Error of Estimate	   12.7180

    . ,,         Regression            Standard          _
Variable          s    .                         .         Computed  T
                Coefficient        Error-Coefficient

Log10 (H)        21.7178               .836625              25.9589

Intercept (C      ) — .344437
            -IL V OO
    Table  21    SUMMARY OF STATISTICS  FOR EQUATION 12
                          (TOG  Correlation)


Proportion of Variance of Y Reduced	   0. 1645
Partial F (DF =  1, 530)	   104. 3881
Cumulative  Sum of Squares Reduced	   25594.4100
Cumulative  Proportion Reduced	   0. 1645 (of
                                                        155542.6000)
Multiple Correlation Coefficient	   0.4056
F  For Analysis of  Variable  (DF =  1,530)	   104.3881
Standard Error of Estimate		   15. 6584
,r   . , ,         Regression             Standard
Variable        _ 6...  .           „      ,-.   ,„. .         Computed T
                Coefficient        Error-Coefficient

Log1()  (H)        10.2977               1.00789             10.2171

Intercept C     _  — 22.3553
                                  149

-------
Table 22   SUMMARY  OF  STATISTICS  FOR EQUATION 13A
     (Wave Depth (W,-.)  Correlation for the 12-inch Sewer)
Statistical
Parameter
Sum of the
Squares
Reduced
(of 2,977}
Proportion
of Variance
WD
Reduced
F (DF =
1, 574)
Correlation
Coefficient
Regression
Coefficient
Standard
Error of
Regression
Coefficient
Computed
T for
Regression
Coefficient
Standard
Error of
Estimate
¥D
Intercept
Statistics For Each of the Independent Variables
L°'5
1207. 0
0.4057
391. 8
0.637
-0. 261
0.00968
-26.96


VF
463. 0
0. 1556
203.3
0.3940
0. 023
0.00158
14. 57


QF
316.0
0. 1064
183.2
0. 3260
0. 534
0.0387
13.83


So
17.4
0. 0059
10. 2
0. 0768
-1. 00
0.340
-2.95


QB
1. 32
0. 0004
0.75
0. 020
2.36
2. 717
0. 868


Statistics
for the
Complete
Relationship
2006. 8
0. 6740
235. 7
0. 8210



1.3049
8.454
                            150

-------
Table 23   SUMMARY OF STATISTICS FOR EQUATION 13B
     (Wave Depth (WD) Correlation for the 18-inch Sewer)
Statistical
Parameter
Sum of the
Square
Reduced
(of 4,007)
Proportion
of Variance
WD
Reduced
F (DF =
1,574)
Correlation
Coefficient
Regression
Coefficient
Standard
Error of
Regression
Coefficient
Computed
T of
Regression
Coefficient
Standard
Error of
Estimate
^D
Intercept
Statistics For Each of the Independent Variables
L°-5

1944. 2


0.4852

540. 9
0. 6965
-0. 322

0. 00994
-32.45




QF

683. 1


0. 1705

283. 6
0.4130
0.408

0. 0306
13. 37




VF

274. 7


0. 0685

142. 1
0. 1620
0. 0189

0.00170
11. 10




°B

52.9


0. 0132

28. 7
0. 1150
7. 286

1. 361
5.353 '




S
0

0. 38


0. 0001

0. 2035
0. 0100
-0. 215

0.4777
-0.451




Statistics
for the
Complete
Relationship

2955. 3


0. 7374

320. 2
0. 8587




1. 3586

8. 839

                              151

-------
Table 24   SUMMARY OF STATISTICS FOR  EQUATION 15
            (Sewage-Flush Correlation,
Statistical
Parameter
Sum of the
Square
Reduced
(of 36, 175)
Proportion
of Variance
°f^ESS
Reduced
F (DF =
1. 82)
Correlation
Coefficient
Regression
Coefficient
Standard
Error of
Regres sion
Coefficient
Computed
T of
Regression
Coefficient
Standard
Error of
Estimate
ACESS
Intercept
Statistics For Each of
the Independent Variables
VF
2693.4
0. 0745
6. 60
0. 2729
-0. 140
0. 0570
-2.449


L
152. 7
0. 0042
0. 371
0. 0648
-0. 00710
0. 0117
-0. 605


QF
15. 5
0. 0004
0. 0372
0. 0200
-0. 242
1. 256
-0. 193


Statistics
for the
Complete
Relationship
2721. 6
0. 0791
2. 2906
0. 2813



20. 41
14. 30
                          152

-------
    Table  25   SUMMARY OF STATISTICS FOR EQUATION 16
                 (Correlation of C~    , to  LOG, 0 H)
                                              1 0
Intercept                                               -13.6990
Regression  Coefficient                                  23.6974
Standard Error of Regression  Coefficient               1.602
Computed T Value                                      10.691
Correlation Coefficient                                  0. 763
Standard Error of Estimate                             10.940

ANALYSIS OF VARIANCE FOR THE REGRESSION
                                     Sum of      Mean      F
   Source  of  Variation        D. F.   Square       Square    Value

Attributable to Regression       1   13677.410  13677.410   114.288
Deviation from Regression     82    9813.332    119.675
Total                         ;83   23490.742
                                 153

-------
                       APPENDIX E

                 LIST OF DESIGN DRAWINGS
                LIST OF  DRAWINGS FOR  THE
                PROTOTYPE FLUSH STATION
LAYOUTS:
E4318852
D4318853
D4318856,
E4318945
E4319113
E4319114
E4319115
                                 3 Sheets
FABRIC FLUSH TANK (as built):
                        D4319173[-
B4319180
B4319189
B4319190
B4319292
C4319176
B4319177
B4319175
                       C4319187
                       C4319186
                       B4319194
                       B4319184
                       D4319185
                       D4319181
                       C4319182
                       D4319183
                       C4319195
                       B4319292
                     155

-------
                                 LIST   OF  DRAWINGS   FOR   THE
                                        TEST  FACILITY  (1   of  2)
 rtSH WATERPlPlflt 1	



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-------
LIST  OF  DRAWINGS FOR  THE
   TEST FACILITY (2 of 2)

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SfVCK FLUSHING
       157

-------
                             APPENDIX F
          DESCRIPTION OF MATHEMATICAL MODEL FOR
               DESIGN OF SEWER FLUSHING SYSTEMS
INTRODUCTION

Since there are a variety of flush station types available,  each with dif-
ferent solids removal characteristics and costs,  an efficient method of
selecting types and locations for installation is required.   The following
discussion addresses itself to this problem.  The problem is to develop
a mathematical model to select the best configuration for locating the
flush stations and determine their capacities to achieve a specified
cleansing efficiency.  The  criterion for evaluation can be either of the
following:

 •  Minimize the total cost of the station's equipment and flush water
    required for operation of the flush stations.

 •  Minimize the quantity of flush water required.

An approach known as a dynamic programming technique is used to deter-
mine the optimal location and type of flushing stations.  Under  this ap-
proach, the analysis proceeds  stepwise from the first upstream location
to the last and  identifies  the most cost effective installation at each
location.

The discussion which follows gives a detailed description of the develop-
ment and use of the model and the computer program.  A sample problem
is also included as well as  a discussion of ways that the existing model
can be extended to be used  for larger, more complex problems.

DESCRIPTION OF FLUSHING STATIONS

A flushing station is designed to release a hydraulic wave of sufficient
magnitude and  duration to cause deposited solids  to become suspended
and be flushed  down the lateral.  The idea is to install a series of these
facilities along a lateral and operate them periodically so as to reduce
the amount of solids which  settle out during low flow periods.

The manner in which this wave  may be  generated is varied: it  might be
a discharge of  clean water  directly into the sewer lateral or possibly a
                                  159

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small check dam to contain sewage and then periodically release it.  The
method of generating the flushing wave is unimportant as long as the
efficiency of removal can be quantified as a function of the relevant phy-
sical parameters.

The  parameters affecting the station efficiency are of three types:

  •   Flush Station Parameters; type of flushing installation, quantity of
     flush water,  and rate of flush discharge

  •   Physical Characteristics; the length, diameter, and slope of sewer
     pipe and the  distance between station installations

  •   Load Characteristics:  The average rate  of base sewage flow and
     the quantity of solids deposited in the flow.

The  Central Engineering Laboratories have performed extensive experi-
ments  to determine the efficiency  of a flushing station as a function of
the  cited parameters.   The equation as developed by the Central Engi-
neering Laboratories gives the functional relationship of average cleans-
ing  efficiency (C^gg) in percent over  the length (L)  as a function of the
length  from the installation (L), the volume (Vjr) and rate (Qp) of the
flush release,  the slope (So), diameter (D), and the rate (Qg) of base
flow.  The experiments show that  the percent solids removal is indepen-
dent of the amount of solids in the  base flow; of course,  the amount in
pounds of solids removed is proportionally greater  for larger solids
loads.

The  average cleansing  efficiency is determined using  the equation of the
following general form:
                  CESS

where A, B, C, D, E,  F, and G are constants determined by a regres-
sion analysis of the experimental results (Equation 10).

Graphically, for constant slope and diameter and a particular flush rate
and volume, the relationship between average efficiency and  distance
from point of installation for a variety of base flows is shown on the
following page.
                                  160

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      100
Average
 Solids 50
Removed
                                       500

                                 Distance, L (ft)
1000
 The above equation is expedient for performing the analysis of the ex-
 periment but is  difficult to work with for the model developed in this
 document.  For purposes of this model it is necessary to convert the
 curves for average efficiency to a curve  for the point efficiency at a dis-
 tance  u from the installation (Cg).  That is,  if a 60 percent efficiency
 is stated for  the distance of 500 ft. ,  the implication of average efficiency
 is that over the entire length of 500 ft. , on the average, 60 percent of the
 solids are removed; under the interpretation of point efficiency the  im-
 plication is that at the distance 500 ft.  from the point of installation,
 60 percent of the  deposited solids are removed.   The expression for
 point efficiency may be  derived from the average efficiency expression
 by using the general relationship
                                    L
                         y(L)  = f f   y(u) du,
                                J-> Jo

 where  y(L) is the average efficiency over L,  and  y(u) is the point effi-
 ciency as a function of distance u from the origin, and differentiating
 both sides.   The result  is,
                             ESS
                                  - FB/log  (10)
where F  and B  are from the above average efficiency expression.
                                  161

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There are several assumptions about the operation of flushing stations
which should be established before the  computational procedure is dis-
cussed.  The first stipulation is that no negative efficiencies (point effi-
ciency) are allowed.  A negative point efficiency implies that solids
would be deposited rather than removed.  It is obvious  that over particu-
larly long  reaches from the installation,the solids would settle out.
There are two tacit assumptions inherent in the stipulation of no nega-
tive efficiencies:  first, that once  in suspension,the solid particles  stay
in suspension (this is fairly reasonable since the plucking velocity is
greater than that required to maintain the solids in suspension); and
secondly,  that installations will be sufficiently close  together so as to
provide additional assistance in keeping the particles in suspension (for
typical levels of flushing efficiencies this assumption should be
satisfied).

A second assumption which significantly impacts the computational pro-
cedures  arises when the efficiencies of two or more stations overlap.
An example of this problem is illustrated below.  Here  a flush station
of type B  is installed at location n  and a station type C is installed at
location n + 1.
 Solids
 Removed
          n
     n  f 1           x

Distance Along Lateral
                                                               n + 2
As is seen in the plot,  station type B has efficiencies which carry over
into the reach beyond the next installation (the stations are assumed not
to act simultaneously).  The question is how to handle these overlapping
efficiencies.  There  are several approaches for which good arguments
                                  162

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can be made.   For the purposes of the model developed here, however,
it is assumed that the efficiency at any point follows the maximum effi-
ciency of either curve.  In the above example then, the efficiency follows
the curve of station type B from location n to n 4- 1,  the curve of station
type C from n+ 1  to X and the curve of station type B again from X to
n + 2.  The argument for this type  of removal pattern is based on grading
the solids into an order based on ease of removal.  If the least difficult
particles to remove are first on the graded list, then conceptually,  the
model assumes that if some particular station type under given condi-
tions will remove 40 percent of the solids,  then the upper 40 percent will
be flushed.  This is equivalent to saying that the station under the condi-
tions given cannot remove  the bottom 60 percent of the solids.  Such
flushing  behavior would be dependent upon the nature of the hydraulic
wave that the  flushing station emits.  If  this is representative of  the be-
havior of a flushing station then the assumed pattern of cleansing for
overlapping efficiency curves is valid.   As long as the stations are opera-
ted independently (so that  the wave of each is  not acting simultaneously),
then together  they would flush no more solids than each would have
flushed by itself.

The  last assumption implicit to the computational procedure  is that  the
sequence of stations along  a lateral are  operated in harmony. That is,
that  there is no interference in the flushing action of any station by any
of  the others.   Certainly if there is constructive interference (e.  g. ,
additive  effects of flushing by multiple stations  operating together) the
model will give conservative cleansing efficiencies.  Basically this  as-
sumption stipulates that,  at the least,  the operation of flushing stations
will  pass to successively downstream locations.

This establishes the necessary operational preliminaries to proceed to
the computational procedure for selecting and locating flushing stations
along a lateral.

THE FLUSHING STATION  LOCATION MODEL

In  equation form, the  model employed to select the locations and station
types for flushing station installations is difficult to interpret and appre-
ciate.  Hence, an intuitive approach through a more-or-less narrative,
discussion is  the best way  to introduce the model.   A more precise  pre-
sentation is found on page  188.    The actual mathematical formulation
is  not presented but can be found in the texts referenced.

The  solution technique is referred to in  the literature as dynamic program-
ming.  This approach to problem solving is frequently employed  in the
optimisation of sequential decision problems; that is, in problems in

                                   163

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which a periodic (either over time or distance) decision must be made.
Before discussing the actual mechanics of the model, however, it is
necessary to establish a couple of points; one is fairly obvious, the
second point is  more subtle and introduces an important crutch to the
actual computation.

Consider a simple  lateral with defined acceptable locations for flushing
stations  as indicated below.  There are n possible locations for flush-
ing station installations along the lateral.  In actual practice,  these
locations may be manholes or otherwise convenient locations  to install
a station.
                                      '   •     —-
                        4               n-2    n-1     n
                            __                              Sewer
                       Flow                                Main

The first point to note is that a flushing station will have effects only
downstream of its point of installation. That is, a station installed at
say location 3, may have consequences (either through the removal or
deposition of solids) from location 3 through the  last downstream  reach
of the lateral, in no case will there be any effects upstream of
location 3.

The second point concerns the specification of cleansing efficiency
along the lateral.  The usual approach in assuring that sufficient solids
have been removed for acceptable system operation is to specify an
average efficiency of total solids removal for the entire lateral.  For
example, if engineering analysis has indicated that along some parti-
cular lateral there would be 200 Ibs  of solid  material deposited in a day
and an acceptable amount of solids remaining in  the lateral were 60 Ibs,
the required efficiency would be specified at 70 percent removal.   There
is no direct way  in this type of problem to solve  for the minimum cost
policy and still be assured of meeting the specified efficiency.  To force
the average efficiency to the specified level it is  necessary to introduce
an artificial or   shadow savings  of  solids removal.   To motivate the
need for this shadow savings consider the following argument.  The pri-
mary criterion for evaluation of a configuration is its cost.  The least
cost sequence of flush stations is the configuration with no installation
which incurs a zero cost, but also a zero efficiency.  If there is some
installation configuration, then,  there has to be a savings implied by the
removal of solids.  This savings implied  by the removal of solids is the
total  shadow savings,   referenced above.  As an example,  suppose for
some station the  installation, operation, and maintenance costs are $50
per month.  It is assumed that the unit shadow savings are $1.  50 per
                                 164

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pound of solids removed and the amount of settled solids are .  1 Ib/ft.
Then if the point flushing efficiency over 800 ft is as graphically illus
trated below,
          100
Solids
Removed
                                                         Distance
                                           800
the net cost, including the  savings of removing solids, of such an instal-
lation is easily calculated:

     Average efficiency (CESS)    = 50%
     Total solids removed         = (. 1 lb/ft)(. 50)(800 ft)  =  40 Ibs

     Total savings due  to removal - ($1. 50/lb)(40 Ib)  $60

     Net  cost of installation       = $50 - $60. = -$10

The net cost of an installation of the above type is -$10 and hence, is
preferable to no installation at this location.

A problem characteristic of this approach is  the difficulty in selecting
the unit value of the shadow savings that will  yield the required level of
efficiency.  The only information known about the  shadow savings is that
small values imply low cleansing efficiencies while larger values yield
high cleansing  efficiencies. The relative magnitude in relation to the
installation and operating costs is not known but a little practice and a
trial-and-error approach to the solution technique should allow a fairly
rapid determination of the  shadow savings implying the required level
of efficiency.   The computer program uses a search technique to auto-
matically determine the shadow savings. TJiis  is done by recursively
solving the model with a new estimate of the shadow savings.   The esti-
mates are generated by doubling previous estimates (starting at $. 01
per unit  removed) until successive  estimates bracket the desired effi-
ciency.  Once bracketed, the shadow savings is more accurately deter-
mined (and the desired efficiency more closely attained)  by a  search
technique known as a "golden section search. "  Details of the technique
                                   165

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are found in Foundations of Optimization by Wilde and Beightler.  Essen-
tially the approach is to successively redefine the interval in which the
shadow savings implying the desired efficiency lies until sufficient accu-
racy is attained.  More specifically,  the model is evaluated at a fraction
of . 618 of the interval and either the 61. 8 percent interval or the 38. 2
percent interval is discarded depending on which of the intervals bracket
the desired efficiency.   The fraction .618 is recursively applied to the
remaining interval.  A manner in which successive estimates of
the shadow savings may be used to give useful information of
investment levels is discussed.

With these preliminaries and the assumptions about flushing  station
operation established in the preceding section, sufficient groundwork
has been laid  to present the computational procedure for locating flush-
ing stations along a lateral.   The approach is to cost out each successive
location selecting that configuration of flushing stations which yields the
minimum cost to the location under consideration.   When the last loca-
tion has been reached the sequence of costs leading to the absolute  mini-
mum cost is retraced to determine the particular station type at each
location.  This is the general approach, but now consider the actual pro-
cedure in more detail.

Begin at the most upstream location; in the example  (page  168) this  is
designated at  Location  1.  Suppose the installation  alternatives are either
no station or one of three distinct  station types.  It is a fairly straight-
forward problem to calculate the net cost of any of the particular alter-
native installations at Location 1.

First determine the costs associated with the purchase installation,
maintenance,  and ope ration of each station at Location 1, and then sub-
tract the  savings generated by solids removal by applying the  unit
shadow savings to the amount of solids removed.  Once this is done for
the first location (including the no station alternative of zero cost) the
procedure with slight variation is  carried to Location 2 and subsequent
locations.   The variation in approach at Location 2 (and subsequent loca-
tions)  is to include the  costs and any cleansing associated with the instal-
lation at Location 1 (and all upstream locations).  Suppose  the station
types are designated A, B,  C, and no station is D.   Computationally
then,  at Location  2, beginning with Station type A,  each station type is
considered and the costs and  savings associated with this station type at
Location 2 is  evaluated by conditioning on each of the immediately pre-
ceding station types (A, B,  C, or  D at Location 1).  Care must be taken
to assure that downstream effects of an installation are considered.  For
each station type at 2,  the minimum of the conditioned costs and the
downstream cleansing pattern are retained for subsequent calculations.
                                  166

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These retained costs are the minimum costs to the  current location for
each station type.  These minimum costs are the only costs which need
to be  considered in subsequent calculations. For example, suppose
station type B were under consideration at Location 2 and the following
conditioned costs were generated:

             Station Type    Cost with Type B Installation
             at Location 1    	at Location 2 ($)	

            Station type A              -19. 50

            Station type B               -34. 60

            Station type C            not feasible

            Station type D               -31. 00

Then under the dynamic programming scheme  it is  necessary to carry
along the cost of -$34. 60 and a preceding station type of B for subsequent
calculations.  This may be interpreted that if through subsequent calcula-
tions  it is determined that there should be a station type of B at Location
2, then the  optimal preceding station type will always be a B at Loca-
tion 1.   For each of the possible station types  there will be the minimum
cost and preceding station type; for example,  the following list might be
obtained:

            Station Type                        Preceding
           at Location 2  Minimum Cost ($)   Station Type
           Station type A         -41.40            B

           Station type B         -34. 60            A

           Station type C     not feasible
           Station type D         -27. 00            B

These costs and  policies are retained for subsequent calculations.

Proceed to  Location 3 for further illustration of the procedure.  If any
particular station type were considered, say type C, the most efficient
means to determine the cost to Location 3 with a type C installation,  is
to evaluate  the costs  and savings of installing a type C  station conditioned
on the cost  and downstream effects of each  possible station type at
Location 2.  No direct consideration of installations at Location 1 is re-
quired since these are accounted for in the  minimum cost and preceding
station type information carried with the station types at Location 2.
Again after the calculations  for cost are completed  for each station type,
the  minimum cost and preceding  station type are retained for purposes
of the  subsequent calculations.
                                   167

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The feasible station types at each location are evaluated in the above
manner beginning at the first and preceding location by location to the
last location on the lateral.  At the final location,  the minimum costs
associated with each of the station types at this location are perused to
find the absolute minimum cost over the entire lateral.  With this  abso-
lute minimum cost,  the problem becomes to identify the sequence of
station types leading to this cost.  This is easily accomplished by work-
ing backward from the last location  to successively preceding locations.
Using  the preceding station type information carried with each station
type at each location it is fairly direct to recursively identify that  station
type at the preceding location which implies  the  cost at the current loca-
tion.   When the sequence has been defined,  the computational procedure
is completed.

Manually this method  becomes quite tedious,  but it can be efficiently
programmed for execution on a computer.  At first the approach seems
little better, if at all, than direct enumeration; there are, however,
significant efficiencies.  Under direct enumeration for  a lateral with say
four possible station types  for installation at five potential locations, there
are 1,  024 ( = 4 ) station configurations to calculate.  Using the technique
of dynamic programming the number of calculations (usually of a much
simpler  nature) is 68  [= 4 + 4 (4^)].   Although it is not as direct as might
be hoped, it is the most efficient method in the solution of this problem.

EXAMPLE

In order to illustrate the solution technique which was described  rather
abstractly in the preceding section,  a sample problem is presented below.
This problem has been greatly simplified to  minimize the basic computa-
tional  requirements.   However,  the  problem satisfactorily demonstrates
the function and flexibility of the optimization technique used in the
mathematical model.

Problem Statement

For the purposes of this example, assume that it is desired to select the
most economical flushing system to periodically remove 60 percent of
the solids deposited in the lateral sewer described by the following
diagram.


         MH1    L.40Q.   MH2    L=800'     MH3   L = 60Q.   Main

                 D =  12"          D = 12"            D =  12'
                                  168

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Information Required

Before the problem can be  solved, the engineer must supply specific
information about the sewer and the flushing equipment that is being
considered.  The following discussions describes the information re-
quired and the  reasons for  its need.

Physical Description of Sewer.  The physical characteristics and geo-
metric configuration of the sewer in question must be completely des-
cribed.   To accomplish this, the engineer must begin by determining
the locations along the sewer where flush equipment of one type or an-
other can feasibly be installed (this would most often be at the location
of manholes. )  He then must number the access locations consecutively
beginning with  the number  1 at the location nearest the  upstream end of
the sewer.  These identification numbers can then be used to describe
the relative position of each access location  and the physical character-
istics of the  sewer between the successive locations.

The lateral sewer under investigation in this example would be des-
cribed in the following manner:
Sewer
Section
1 - 2
2-3
3 - M
Sewer
Length
-L-
(ft)
400
800
600
Average
Slope
-S0-
(%)
1. 0
1.0
1. 0
Pipe
Diameter
-D-
(ft).
1.0
1. 0
1.0
Hydraulic Characteristics.  The engineer must also analyze, the sewer
and the area which it serves and describe the expected dry weather
hydraulics.  He must either make statistical estimates or field determi-
nations to define the average solids concentration expected to pass
through each of the sections of the sewer.  Also, he must determine
what is a reasonable time between successive flushings and what the
expected  buildup of solids deposits would be in each of the sections of
the sewer during this time interval.
                                  169

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In this example,  the following hydraulic characteristics will be used:

                     Average        Solids        Frequency
                    Flow Rate     Deposited      of Flush
          Sewer        -Qfi ~           -Ds-          -Fp-
          Section       (cfs)       (Ibs/ft/day)     (No. /Days

           1-2        0. 05           0. 01          1. 0

           2-3        0. 05           0. 01          1. 0

           3  - M       0. 05           0. 01          1. 0

Flush Equipment Characteristics.  The engineer must determine the
characteristics and limitations of the various types of flush devices
which are available and then decide which ones can realistically be used
in his situation.  He must also analyze each of the  access locations
along the  sewer in question and determine which of.these devices cannot
be used due to  the physical location of the access point and the limita-
tions caused by obstructions in the surrounding area.

Having accomplished the  above,  he  must then list all of the types of
flush devices that can be  used on the lateral and determine the following
physical characteristics and cost information for each:

1.   Determine the purchase cost, expected life, storage volume,  and
     average release rate of the  smallest available  size of each type of
     flush device  to be used.

2.  Estimate the total installation cost and monthly maintenance cost of
     each  of the flush devices at  each  of the locations where  the specific
     type can be used.

3.  Determine  which of the flush devices to be investigated will use
     clean water as the  flush media, and which will use sewage.  Also
     estimate the unit cost of handling the flush media ($/ft^) that is
     associated with each of the flush  devices.

4.  Determine  the  maximum size (largest  storage volume) of each
     device that can be used at each of the access locations.

5.  Determine  the variable cost of purchasing and  installing at each
     location, sizes of each device which are larger than  the minimum
     sizes available in $/ft^ of volume in excess of the  storage volume
     allowed by the smallest available size  of each  type of flush device.
                                170

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For this example,  the  physical characteristics and estimated costs to
be  used for  the flush equipment are described  as follows:

1.   The  general characteristics  to be used for the smallest available
     size of  each type of flush device to be investigated,  are as follows:



Station
Type.
A
B

Storage
V olume
-V min. -
(ft3)
30
30
Average
Release
Rate
-QF-
(cfs)
1.0
2.0

Purchase
Cost
-C -
(«
500
800
Varlable(b)
Purchase
Cost
-ACp-
($/ft3)
10.0
15. 0

Expected
Life
-P-
(years)
20
20

Monthly
Cost
-Cm-
($)
200
200
Cost
Flush
Media
-Ac0-
($/ft3)
0. 001
0. 001

Cost(d)
Volume
Exponent
-Ke-
1. 0
1.0
 Notes:   (a)  The Type C flush station represents the alternative which must always be investigated,
             that of not installing flushing equipment at any of the given locations.

         (b)  This is the additional cost ($/ft3) of purchasing the specific type of flush device per
             cubic foot of volume in excess of the storage capacity of the smallest  size unit
             available.

         (c)  This is the average cost of handling and storing each cubic foot of the  flush media as
             governed by the operation characteristics of each specific type of flush device
             (operation cost).
         (d)  This exponent allows the engineer to express "Variable Costs1' as a function of in-
             creased volume (volume in excess of that associated with the smallest available size
             of flush device in a nonlinear
             function).
fashion,  Ke = 1. 0 gives a linear variable cost
 2.   The cost of installing each type flush device at each of the proposed
     access  locations:
                 Location 1
    Location 2
                                                                     Location 3



Station
Type
A
B
C
Minimum(a)
Installation
Cost
-Gi-
ft)
100
50
_
Variable(b)
Installation
Cost
-ACi-
($/ft3)
1.00
0.50
_
Minimum(a)
Installation
Cost
-Gi-
ft)
150
100
_
Variable(b)
Installation
Cost
-ACi-
($/ft3)
1.50
1.00
_
Minimum(a)
Installation
Cost
-Ci-
($)
50
50
-
Variable(b)
Installation
Cost
-ACi-
($/ft3)
0.50
0.50
-
 Notes:    (a)   This is the cost of installing the smallest available size of a given type of
               flush device at the given location.
          (b)   This is the additional cost,  per cubic foot of increased volume, of install-
               ing, at each given location,  flush devices with storage capacities greater
               than that allowed by the smallest unit.
                                            171

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3.  The limits on the maximum sizes of flush devices which can be used
    at the various access locations,  as governed by the physical charac-
    terestics of the access locations.
        Station  Ratio of the Maximum Allowable  Storage Volume
        Type      to the Storage Volume of the Smallest Unit
                                   -RV-

                    Location 1     Location 2     Location 3
A
B
C
2.0
3.0
—
3.0
2.0
—
4.0
3.0
_
    As can be seen by the simplicity of the hypothetical sewer being used
    for this example, and the uniformity of the physical and hydraulic
    characteristics and cost relationships selected for the sewer and
    flush equipment,  the computational procedures involved are  much
    less complicated and the number of  alternatives to be investigated
    are considerably less than will normally be the case when a  flush
    system is to be designed for an actual existing  sewer.  However,
    this example has been simplified to  this extent  in order to allow the
    reader to more readily  understand the overall operation of the model
    and the optimization technique  used.

Application of Model

Once the above information has been established and supplied  to the com-
puter program, the computer performs a series of  computational opera-
tions which are described in detail in the following discussion.

Volume Determinations.  First, the maximum allowable  size  (storage
volume) is determined for each type of flush station at each of the pro-
spective access locations.  This is  accomplished  by multiplying  the vol-
ume of the minimum size of each type of station (V  min) by the ratio of
the maximum allowable volume to the minimum volume for each  type of
flush  station at each access  location (Rv).  For instance, the maximum
size of station Type A that can be installed at Location 1  is,

                       V      = V  .   x R
                        max     mm    v

                              = (30ft3)  x (2.0)

                              = 60  ft3
                                  172

-------
Next, two intermediate  storage volumes (Vj) are selected for each type

of flush station at each of the locations.  This is accomplished as

follows:
                      AV.  =  (V     - V  .  )/3. 0
                         i      max    mm

                       V.  =  V  .   + AV
                         i     mm      i

                       v  =  v  .   + AV.
                         1     mm      i

                       V  = V  .   + 2AV.
                         £      mm       i



For example, the intermediate volumes for station Type A at Location 1

would be,



                     AV. =  (60 -  30)/3 =  10 ft3
                         i


                       V. =  30  +  10 =  40 ft3
                       V   =  30 + 2 (10)  =  50 ft"
                        LJ                      -
The flush station volumes that would be investigated by the model are:



                   Volumes at Each Location - Cubic Feet
Station
Type
A
B
C
Location
V . V.
mm 1
30
30
_
40
50
_
V2
50
70
_
1
V
max
60
90
_
Location
V . V
mm 1
30
30
_
50
40
_
V2
70
50
_
2
V
max
90
60
_

V .
mm
30
30
_
Location
vi vz
60 90
50 70
_ _
3
V
max
120
90
_
However, in order to minimize the computations, only the maximum and

minimum volumes will be used in the remainder of this example.



Cost Determinations.   The total monthly cost of purchasing, installing,

operating and maintaining each size (volume) of each type of station at

each access location must now be determined.   This  is done in the man-

ner described below.



 9  Purchase Cost (Pc).   The monthly purchase cost is determined by the

    amortization  of the purchase price  over the expected life of the equip-

    ment,  P, and at an annual discount rate of 6 percent.
                                   173

-------
P
 c
                r                                       K 1

           = —  C  + AC  (^Volume to be used - V   . ")  C •
             12 [_  p      p V                       mm/   J
                            x (amortization factor at 6% for P years)




   For example, the monthly purchase cost of the maximum size

   (volume) of a Type A flush station to be installed at Location 1 is:






         P  = -^-[$500 +  ( $10 /ft3)  V60  ft3 - 30 ft3)   J
           C    \. L*

                   x  [amortization factor (6%, 20  years)]


                   =  Y2-[($800)x (0.08718)]


                   =  $5. IB per month.



   The monthly purchase costs for this example are as follows:


            Location 1         Location 2        Location 3
Station
Type
A

B

Size
(ft.3)
30
60
30
90
(,$/Mo.)
3. 63
5. 18
5. 81
12. 35
Size
(ft3)
30
90
30
60
pc
($/Mo. )
3. 63
7.99
5. 81
9. 08
Size
(ft3)
30
120
30
90
PC
($/Mo.)
3.63
10. 17
5. 81
12. 35
 NOTE:  (a) Maximum and minimum sizes  only are included in this

 example.



•  Installation Cost ,(IC).   The monthly installation cost is determined

   in much the same manner as the monthly purchase cost.
                12
                    C.  + AC. (Volume used  -  V
                                             K 1
                                         -  -  H
                                         mm/   J
   For example, the installation cost at the largest Type A station at

   Location 1 is:
                               174

-------
           I  = TrfaiOO +  $1.00/ft3(60  -  30)1'0]
            c   12 L
                x [amortization factor (6%  - 20 years)]

                = -y [($130)  x (0.08718)]

                = $0.94/Mo.

The monthly installation costs for this example are as follows:

              Location 1      Location 2      Location 3

                                            Size      Ic
                                            (ft3)  ($/Mo.)
                                             30     0.73
                                            120     0. 69
                                             30     0. 36
                                             90     0.58
Station
Type
A

B

C
Operating
Size Ic
(ft3) ($/Mo.
30
60
30
90
-
Cost
0.73
0.94
0. 36
0. 58
-
(C0). The
Size
) (ft3)
30
90
30
60
-
monthly
Ic
($/Mo.)
0.73
1.74
0. 36
0.94
-
operatin
taking the product of the cost per cubic foot of flush media (ACO),
the volume of each flush (Vjr),  and the flush frequency (Fjr), times
365 days/year divided by 12  months per year.  For example,  the
monthly operating costs  a,t a Type A station of maximum size at
Location 1 is:

              C   =  (AC   x V^ x F,., x 365)/12
               o        o    .t     -t
                  =  (0. 001 x 60 x 1.0 x 365)/12

                  =  $1. 58/Mo.

The operating  costs for this  example are:

              Location 1      Location 2      Location 3
   Station   Size    Co     Size    Co     Size    Co
    Type    (ft3)  ($/Mo.)   (ft3)  ($/Mo. )   (ft3)  ($/Mo. )
A

B

30
60
30
90
0.91
1. 82
0.91
2.74
30
90
30
60
0.91
2.74
0.91
1. 32
30
120
30
90
0.91
3. 65
0.91
2.74
                              175

-------
Total Monthly Cost (Mc).   The total monthly cost of each type of
station is determined by summing up all of the individual costs.
For example,  the total monthly cost of a Type A station of maximum
volume at Location 1  is:

                  M  = P   +1  +C   +C
                    c     c     c    o     m

Cm is the monthly maintenance cost and was one of the given cost
input parameters.

             M  =  $5.18 +  $0.94 + $1.82 + $2.00

                 =  $9.94

The total monthly costs fo i' this example are:

               Location 1       Location 2      Location 3

    Station   Size     Mc      Size     Mc     Size     Mc
     Type   (ft3)   ($/Mo. )   (ft3)   ($/Mo. )   (ft3)   ($/Mo.
A

B

30
60
30
90
7. 27
9. 94
9. 08
17. 67
30
90
30
60
7.27
14. 47
9. 08
13. 84
30
120
30
90
7. 27
16. 51
9. 08
17. 67
Maximum Cleansing Determination. The maximum cleansing effi-
ciency that can be attained within the limits and  specifications es-
tablished above is determined, without regard to optimization of
cost, by allowing the value of  shadow savings   to approach infinity.
With the value of saving associated with removal of the solids de-
posited in the sewer being very high (the effect and meaning of the
shadow  savings   is discussed more fully later in this section), the
emphasis is  shifted completely from optimization of the  system
with respect to cost to maximization of the  solids removal.  The
maximum cleansing efficiency is determined in the same basic man-
ner as described in the next section for the selection of the optimum
(cost) flush system, except that only one pass  is  made with an ex-
tremely high value of  the  shadow  savings,   say, $10,000 per pound
of solids removed.

The  maximum cleansing efficiency is determined at the very begin-
ning for two  reasons;  first,   so that the user will know what the
maximum limit of the proposed system is and,  second,  to make
sure that the desired system efficiency (specified by the user) is
                             176

-------
possible within the specified limits.  Once the maximum cleansing
efficiency has been established, it is checked against the value
Specified by the user.  If the  maximum value is less than the desired
value, the  computations are terminated and the maximum allowable
efficiency is printed  out so that the user knows that  the limits he has
specified for the system are too small and must be increased  if the
desired efficiency is  to be realized.  If the maximum value is greater
than the desired value, the value of the  shadow  savings is adjusted
downward and the process of optimizing the system with respect to
cost is started and proceeds as described in the following section.

Optimum System Selection.  The cost optimization of the system is
accomplished using a dynamic programming technique which involves
the use of a corrected multiplier which in this case will be referred
to as the  shadow  savings.    This multiplier can be thought of as
representing the dollar value of removing a pound of deposited solids
from the given sewer.  The program is constructed such that the
user can estimate the dollar value of removing a pound of the  solids
deposited in the sewer  each day,  based on the costs of alternate
methods of accomplishing the same function,  or the penalty for not
removing the  solids,  and the  model will determine the. most economi-
cal flushing system and corresponding cleansing efficiency such that
the monthly costs of  the system do not exceed the total value of
removing the  deposited solids,  as limited by the value of  shadow
savings  given.  Or the user can supply the model with the desired
cleansing efficiency (average over the  length) and the model will,  by
trial and error, establish the most economical flush system that can
be used to accomplish this  specified level of cleansing.

Because the basic computational procedures are the  same when
either of the above described approaches is used and because in most
cases the user will probably know most exactly the cleansing effi-
ciency he desires, this example will approach the problem by taking
an assumed value of  the  shadow savings and correcting it to obtain
the specified cleansing efficiency.  As previously described in the
description of The Flushing Station Location Model,  the model begins
with a value of shadow savings  and correcting it to obtain the speci-
fied cleansing efficiency.  As previously described,  the model be-
gins with a value of shadow savings of  $0. 01 per pound and then
doubles the value  repeatedly until the desired cleansing  efficiency
is reached or exceeded and then further refines the estimate using
the "golden section search" technique.  However, for the purpose
of this example,  the  initial repetitive computation will be eliminated
by assuming a value  of shadow  savings  of $5. 00 per pound of solids
                               177

-------
removed, which will give a more realistic cleansing efficiency based
on the costs and limits that have been arbitrarily selected in this- case.

The first step in the system optimization is to determine the total
cost (including the  shadow savings)  of each size of each type of
flush station that can be installed at the upstream most access loca-
tion (Location 1).  Since  the monthly cost of  each of the various
sizes and types  of flush stations has previously been determined for
this example,  the  only major determination that is left to be made
is that of the savings that can be accomplished, based on the solids
removal in each case  and the value of the  shadow  savings.   In this
example, the flush media will be taken as clean water, in all cases,
in order to simplify the computations.  However, if sewage  is to be
used as the flush media,  the computations are much the same ex-
cept that the clean water cleansing  efficiency must be corrected using
Equations 14 and 15 and the procedures previously described in the
Discussion section of  this report.

The average clean-water cleansing efficiency over a  given length of
sewer,   Cjr;ss> can be determined using Equation 10 as long as the
value of L used is taken from the point at which the flush release
is made.  However, the computations involved in this model require
that the average cleansing efficiency be determined for sections  of
sewer downstream of  the point of flush release, the upstream ends
of •which do not coincide with the point of flush release.  Therefore
the differential form (with respect to L) of Equation 10 is more use-
ful (point efficiency equation, C-g).   The development of this point
efficiency equation in  its general form was described in the preced-
ing section.  The specific equation used in this model is:
                                                          4
  CE(L) =  -30. 87 + 24. 68 log^ — - ^   ° 2 -  x 10
                                       '
The above equation for Cg can be used to determine the average
cleansing efficiency for any section of sewer downstream of the
point  of flush release by integrating it with respect to L between the
specified limits of L (L. is always the distance from the point of
release). For example,

                                     L3
                 (for Section 2-3)  =   f     C£  (L) dL .

                                    L2
Where L/£ is the distance from the point of flush release to the
                             178

-------
   upstream end of the section,  L-j  is the distance from the point of
   flush release to the downstream end of the section,  and CTP (L) is
   the point efficiency equation which is a function of L.   The quantity
   of solids removed by the flush wave  from the  section of sewer be-
   tween Location 2 and Location 3 (SR)  can be determined,
S  (from Section 2-3) =
 Jtx
'    1
3D 100
 JU
/
                                                CE(L)
   where  S  is the total quantity of solids deposited in Section 2-3.

   The model begins at the upstream most location (Location 1) and
   determines the total cost (including savings) for each type of station
   that can be installed at that location.  For this example,  the total
   cost of the largest Type A station at Location 1 is determined as
   described below.

   First,  the total quantity of solids deposited in each section of sewer,
   Sj), during the interval between flushes is determined.  The total
   quantity of solids deposited in the section of sewer between Loca-
   tions 1 and 2 is,
   D
                 = DS

                 = (0.01 Ibs/ft/day) (400 ft)/(l. 0/day)

                 = 4. 0 Ibs
   The quantity of solids deposited between flushes in each of the sewer
   sections is given below.
           Section    Deposited
Section  Length -L-  Solids -Dg
  No.       (ft)	(Ibs/ft/day)
                         0. 01

                         0. 01

                         0. 01
                         Frequency of
                 Total Solids
                  Deposited
                          Flush -FF_   Between Flushes
1-2
2-3
3 -Main
400
800
600
                          (No. /day)

                              1.0

                              1.0

                              1. 0
                  -Syr (Ibs)
                    4.0

                    8. 0

                    6. 01
   Beginning at the upstream most location (Location 1), the quantity of
   deposited solids removed from each section of sewer by each size
   and type  of flush device that can be installed at this location is
                                 179

-------
   determined.  Then the solids removal quantities are used to determine
   the  saving and costs associated with each of the installations.  The
   quantity of deposited  solids removed from each section of the sewer
   is determined for each type and  size of flush station by integrating
   the  point efficiencies over the length of each section and multiplying
   the  average cleansing efficiency obtained for each section by the
   total quantity of solids deposited in each section.

   In the actual model, the  integral in the above relationship for SR  is
   evaluated more  exactly using small increments of L,   over  the
   length of each section.  However,  for the purposes  of this example,
   the  point efficiency function will be assumed to be linear along the
   length of each section.  For example,  the solids removed from each
   of the sections of sewer  by the smallest  Type A station installed at
   Location 1,  is determined as follows:

   For Section 1-2,
ESS
                          (400)1'6 (0..05)1'
                                                              x  10
     = -13. 70  +  24. 68 log    (2080)

     = 68. 6%
 S_  = 4.0(0.686) = 2.74 Ibs
   For Section 2-3,
         1
 'ESS
•(C  @ 2
                         @ 3)
C_ @ 2 = -30. 87  + 24. 68 log
 E

        = 51.4%

C   @ 3 = -30. 87  + 24. 68 log

        = 32. 3%
                            10
                            (400)1'6 (0.05)1'2
                                                               x  10
                                3. 02 x  10
                               _ (1200)
                                       1.6
   S_.  - (8 Ibs) (41. 8%)/100
    K.
       = 3. 34 Ibs
                                180

-------
    For Section 3 - Main,
   ESS

CE@4
   ESS

     SR
          T
-------
The total costs and solids removals associated with each size and
type of flush station at Location 1 are as follows:


Station
Type
@ 1
A

B


Flush
Volume
-VF-
(ft3)
30
60
30
90
Total
Month
Cost
-Mc-
($)
7.27
9.94
9.08
17. 67

Section
of
Sewer
Cleaned
1-2
1-2
1-2
1-2

Solids
Removed
(SR)
(Ibs)
2.74
3. 11
3. 00
3.61



Savings
($)
13.70
15. 55
15. 00
18.05


Total
Cost
($)
-6.43
-5. 61
-5.92
-0. 38
The total costs given above are all less than zero,  indicating that
with a value of  shadow savings of $5. 00 per pound, any of the
proposed flush stations is preferable to not installing a flush station
at Location 1 (Type C station).  Also since the smallest Type A  sta-
tion has  the lowest cost,  it  is obviously the best alternative  to com-
bine with the proposed flush stations at Location 2.  However, when
the proposed flush stations  at Location 1 are compared to the Type C
or "no-installation" alternative at Location 2, the above cost values
must be  recalculated to account for the additional  savings associated
with the  solids removed by  each in Section 2-3,  as will be shown
later.

Now the  deposited solids  removed from each downstream section of
sewer by each of the  types and  sizes of flush stations to be investi-
gated at  Location 2 are determined.  They are determined in the
same manner as previously used for the flush stations at Location 1
and are given below.
Station
Type
@ 2
A

B

Flush
Volume
-VF-
(ft3)
30
90
30
60
Solids Removed, SR,
(Ibs)
Section
2-3
4.48
5.73
5. 04
5. 81
Section
3 -Main
2.05
2.95
2.43
3.01
                                            Total Length
                                                 of
                                              Sewer

                                               6.53
                                               8.68
                                               7. 47
                                               8.82
                             182

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The total cost of each flush station to be investigated at Location 2
can be determined in the same manner as that used for Location 1.
The results are as follows:


Station
Type
@ 2
A

B


Flush
Volume
-VF-
(ft3)
30
90
30
60
Total
Month
Cost
-Mc-
($)
7.27
14.47
9. 08
13.84

Section
of
Sewer
Cleaned
2-3
2-3
2-3
2-3

Solids
Removed
-SR-
(Ibs)
4. 48
5.73
5. 04
5. 81



Savings
($)
22. 40
28.70
25.20
29. 10


Total
Cost
($)
-15. 13
-14.23
-16. 12
-15.26
The best combination of flush stations at Locations 1  and 2 can be
determined,  simply by adding the total cost given above for each
flush station at Location 2 to the total cost of the least-cost alterna-
tive at Location 1.  However; before the Type C or no-installation
alternative at Station 2 can be evaluated, the  costs of all the types
and sizes of flush stations at Location 1 must be corrected to include
the additional savings associated with the solids removed by each in
Section 2-3.  For example, the adjusted cost of the largest Type A
at Location 1  with a Type C station at Location 2 is,

  Adjusted Solids Removed = (solids removed from Section 1-2)
                             +  (solids removed from Section 2-3)
                           = 3. 11 Ibs  + 3. 98 Ibs  =  7. 09 Ibs

       Adjusted Total Cost = Total Monthly Cost - Savings
                           = $9.94  -($5. 00/lb)(7.09  lb)
                           = $25. 51

The adjusted costs and solids removals for each of the  sizes and
types of flush station  at Location 1 are given below:
                               183

-------

Station
Type
@ 1
A

B


Flush
Volume
-VF-
(ft3)
30
60
30
90
Total
Month
Cost
-Mc-
($)
7.27
9.94
9. 08
17. 67

Section
of
Sewer
Cleaned
1-3
1 -3
1-3
1-3

Adjusted
Solids
Removed
(Ibs)
6. 08
7. 09
6.75
8. 58

Adjusted
Savings
($)
30. 40
35. 45
33.75
42. 90

Adjusted
Total
Cost
($)
-23. 13
-25. 51
-24. 67
-25. 23
The lowest cost combination of flush stations at Locations 1 and 2
can now be determined in the following manner.  First the total
cost and solids removal must be determined for each possible com-
bination.  For example, the total cost and solids removal associ-
ated with  the installation of the smallest Type A station at Loca-
tion  1  and the largest Type A station at Location 2 is,

  Total Solids Removed  - (solids removed from Section  1-2 by the
                          flush station at Location 1)
                          + (solids  removed  from Section 2-3 by
                          the flush station at Location 2)
                        = 3. 00 Ibs + 5.73 Ibs
                        = 8.73 Ibs

            Total Cost  = (total cost of flush  station at Location 1)
                          + (total cost of flush station at
                          Location 2)
                        = $6.43 + (-$14. 23)
                        = -$20.66

The cost and solids removals for the various combinations  of flush
stations at Locations 1 and 2 are  given below.
                             184

-------
Station at Location ra'

Type
A

A

A

Volume
30

30

60
Section
Cleaned
1-2

1-2

1-3
Station at Location 2

Type
A

B

C

Volume
30
90
30
60
_
Section
Cleaned
2-3
2-3
2-3
2-3
_
Solids
Removed
(Ibs)
7.22
8.47
7.78
8. 55
7. 09

Section
Cleaned
1-3
1-3
1-3
1-3
1-3
Total
Cost
($)
-21. 56
-20. 66
-22. 55
-21. 69
-25. 51
Note:  (a) These station types and sizes were selected because they were previ-
         ously found to be the least costly for the given section of sewer to be
         cleaned.

The cost figures given above indicate that the most economical com-
bination of flush stations at Locations 1 and  2 is a Type A with a
60 ft^ storage capacity at Location 1  and  a Type C (no-installation)
at Location 2.  This combination with the corresponding cost and
solids removal information is now used to determine the best type
and  size of flush station for  Location 3.

As was the case at the upstream locations, the quantity of solids
removed and the associated  costs must first be determined for each
type and size of flush  station at  Location  3, when each is used to
clean the next adjacent downstream section of sewer.  These figures
are:

Station
Type
@ 3
A

B


Flush
V olume
-VF-
30
120
30
90
Total
Month
Cost
($)
7. 27
16. 51
9. 08
17. 67
Section
of
Sewer
Cleaned
3 -Main
3 -Main
3 -Main
3 -Main
Solids
Removed
-SR-
(Ibs)
3. 68
4. 82
4. 07
4.76


Savings
($)
18. 40
24. 10
20. 35
24. 30

Total
Cost
($)
-11. 13
-7. 59
-11. 27
-6.63
Now as was done at Location 2 for the flush stations at Location 2,
the solids removals and costs for the flush stations at Location 2
should be adjusted to allow proper evaluation of the Type C station
(no-installation) at Location 3.  However, since a Type C station
(no-installation) is indicated at Location 2, the adjustments must be
made again to the costs and solids removals for the flush stations
at Location 1.  The adjustment is made by simply adding the  solids
removals and associated savings that each station at Location 1
                                185

-------
effects in Section 3-Main to the corresponding adjusted solids  re-
movals and savings determined previously at Location 2.  The ad-
justed values are given below:


Station
Type
@ 1
A

B


Flush
Volume
-VF-
(ft3)
30
60
30
90
Total
Month
Cost
-Mc-
($)
7.27
9.94
9.08
17. 67

Section
of
Sewer
Cleaned
1 -Main
1 -Main
1 -Main
1 -Main
Adjusted
Solids
Removed
-SR-
dbs)
7. 80
9.36
8.80
11. 60


Adjusted
Savings
($)
39. 00
46.70
44. 00
58. 00

Adjusted
Total
Cost
($)'
-31.73
-36.76
-34. 92
-40. 33
The above figures show that the Type B station with a 90 ft3 capacity
is the best selection for the evaluation of the Type C (no-installation)
station at Location 3.   The solids removals and costs of the various
combinations of flush stations along the length of the sewer are as
follows:
                                               Combined Stations
Upstream Stations
@ L.OI
Type
A

AB

cation 1
Volume
(ft3)
60

60

@ Location 2 Station at Location 3
Type
C

C

Volume
(ft3) Type
A

B

Volume
(ft3)
30
120
30
90
Section
Cleaned
3 -Main
3 -Main
3 -Main
3 -Main
Section
Cleaned
1 -Main
1 -Main
1 -Main
1-Main
Total
Solids
Removed
(Ibs)
10.77
11.91
11. 16
li;85
Total
Cost
-36.69
-33. 10
-36.78
-32. 14
       90
                          1-Main   11.60
-40. 33
The figures given above indicated that the best periodic flushing sys-
tem for this particular lateral sewer,  within the limits given and for
a  shadow savings  of $5. 00 per pound of solids removed, is one
consisting only of a Type B flush station with a  volume of 90 ft
installed at Location 1.  The average cleansing efficiency,  Cjrjgg,
over the total length of the  sewer is determined by dividing the total
quantity of deposited solids removed from the sewer by each flush
(11. 60 Ibs) by the total quantity of solids deposited in the sewer be-
tween flushes (18. 0 Ibs).  Thus the average  cleansing efficiency,
      , for the proposed flushing  system is,
                            - 6o lbs x
ESS
                        ~     18. 00 lbs
                        = 64. 0%
                              186

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    This value of Cj^gg is quite close to the value  of 60% which was
    originally specified, so no further refinement is necessary.  However,
    if the actual value of CESS na-d been significantly higher than the
    desired value, the estimate could be refined by reducing the value of
    shadow savings   a small amount (say from $5. 00/lb to $4. 50/lb)
    and repeating the above procedures until the actual value of CESS
    becomes  sufficiently close to the desired value.

EXTENSIONS OF MODEL

Flushing Efficiency Versus Investment Relationship

The first impression of using the shadow savings for  solids removal is
that it is an awkard,  artificial technique.  There is,  however,  significant
power in the utilization of this artificial cost.  Although the average ef-
fectiveness of flushing is usually of prime interest, another and possibly
more realistic question is:  What is the best system that can be installed
for X dollars?   Whereas, keeping the  level of pollutants within some
specified amount is the major engineering concern, the communities
installing a flushing network might typically be interested in considering
the various investment alternatives for control.  These communities may
in fact, be evaluating whether to install flushing  stations or an alterna-
tive such as temporary storage facilities.

To satisfy these  interests a flushing efficiency versus investment rela-
tion would be  beneficial.   An investigation of this is easily motivated by
the shadow savings approach.  By performing the optimization repeatedly
beginning with the artificial shadow savings at a  small value and  continu-
ously increasing the value until either the  maximum investment or maxi-
mum feasible efficiency is attained, a curve of flushing efficiency versus
investment can be generated.  By proceeding in this  manner,  there is
always the assurance that the installation is kept cost effective.  The  re-
sulting plot would have a form somewhat as that  shown below.
Solids
Removed

(Avg.
 over     50
 Lateral)
                                          Each dot represents a
                                          given flushing system
                                 Investment ($)
                                    187

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Approach For Sewer System Analysis

The model presentation and discussion to this point has been oriented
toward the analysis  of a particular lateral in a sewer system.   The
orientation may be expanded to include the entire system if the flow in
the main sewer conduit is  sufficient to remove the solid materials which
might be deposited in it, or may be analyzed independently.  In such a
case, the model may be applied to each lateral individually using one
specific value of the shadow savings over the entire  system.  For exam-
ple,  if the value of . 15 per unit solids removed were applied to each lat-
eral,  some might  be flushed to an efficiency of 75 percent while others
sould be 40 percent  or 55 percent.  The differing flushing efficiencies
indicate that on some laterals  the quantity of solids removed is not suf-
ficient to justify expenditures on flushing  stations.  In general, higher
efficiencies for a  given shadow savings would be associated with laterals
with high solids loads.  Once the  entire system is evaluated with a given
shadow savings, the overall efficiency is  assessed.  If necessary, the
unit shadow savings  is adjusted and the procedure repeated. This ap-
proach could consume considerably more computation time, but the sav-
ings and advantages  of balancing overall effectiveness would justify the
additional expense.  The computer model as developed and presented here
would require the  manual input and adjustment of shadow savings (even
this requires a  special code -  see computer model write-up) to obtain
either the  system  analysis or the efficiency  versus investment relation-
ship.  The model  could be altered without too  much additional difficulty
to allow for automatic development of either or both of these features.

DISCUSSION OF DYNAMIC PROGRAMMING

Dynamic programming is a computational technique which finds applica-
tion in the solution of sequential  decision problems.   The particular
types of problem to which  the approach is most easily applied are those
in which benefits yielded at one stage  of the  problem are additive to bene-
fits accrued in prior stages.  A corollary of this  is that decisions only
have consequences in successive  stages of the problem.   This  is  pre-
cisely the  type of  problem presented in location flush station facilities.

The theory of dynamic programming is more intuitive than analytic and
is more easily grasped by example than through a mathematical approach.
The reader interested in a more precise development and further areas
for application is  referred to any of the standard  texts on the subject
(particularly good presentations  are found in G. L. Nemhauser, Intro-
duction to Dynamic Programming, and G. Hadley, Nonlinear and Dynamic
Programming).  The fundamental property upon which the theory of
                                 188

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dynamic programming is developed is called "the principle of optimality"
and is stated.as:

    "An optimal sequence  of decisions in a multi-stage decision prob-
    lem has the property that whatever the final decision and state
    preceding the terminal one,  the prior decision must constitute an
    optimal sequence of decisions leading from the initial state to that
    state preceding the terminal one."

The validity of this property may be verified by contradiction.

Expanding on the computational procedure to include five possible lo-
cations will show the model to  be an application of the principle of
optimality.   To illustrate this more explicitly, begin at the last stage
of the decision problem, the sewer main. The efficiencies generated
by installation of any of the station types between Location 5 and the
sewer main constitute the various  states that can be assumed under
the different decisions of installation.  Then by the principle  of opti-
mality that sequence of decisions (station types) and states  (resulting
efficiencies) from the initial state  (the result from a decision at
Location  1) to the state preceding the  terminal state (efficiencies ac-
crued to Location 5,  including  the  installation at 4) must be optimal
for a final optimal decision as  to station type at Location 5.   And how
is this optimality to the state preceding the terminal  state assured?
By redefining the terminal state to be that state from Location 4 to the
end of the lateral and applying  the  principle  of optimality to the state
preceding the installation at 4.  To assure that the state preceding the
installation at 4 is  optimal, the terminal state is  redefined to be that
state from Location 3 to the sewer main.  Hence,  following this argu-
ment,  the principle of  optimality is applied recursively with the
terminal  state becoming that state from Location 2 to the sewer main
and then from Location 1 to the sewer main.   This may be done because
the principle of optimality  must be valid over any particular definition
of initial  and terminal  states.

At first this may seem backward from the approach taken in  the solution
technique; it is in fact  the  same approach.  The above paragraph indi-
cates that it is necessary to successively calculate the optimum sequence
of decisions from the initial state to the terminal state by recursively
redefining the terminal state.  This is the manner in which the computa-
tional technique proceeded: The initial state was the consequence of a
decision at Location 1  to the end; in effect, the terminal state and initial
state were the same.   The terminal state was  then redefined so as to be
the consequences from Location  2  to the sewer main where the various
states were determined by the  decisions at 2 conditioned on the various
states preceding 2 (the states implied by the  decisions at 1).  When  the


                                   189

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states associated with a decision at Location 2 have been evaluated, the
terminal state is redefined to be from Location 3 to the sewer main.  By
the principle of optimality the optimal return for this  reduced problem
is found by conditioning on the preceding states (which are themselves
optimal).  This procedure is performed until the last  location in the prob-
lem is reached.

There is a mathematical representation for dynamic programming.
Whereas, for completeness  it would be nice to present this form,  the
definitions necessary for precise formulation make it impractical to do
so.  The interested reader will find formulations in the referenced texts.

COMPUTER PROGRAM

Introduction and Use of Program

The program allows the automatic determination of the flushing  station
configuration yielding the minimum cost for a specified average cleans-
ing efficiency.  As presented, the program is designed for use with the
station types developed by the Central Engineering Laboratories.  The
particular impact of this is in the equations expressing cleansing
efficiencies.

The intent of this discussion is to detail the requirements  for use of the
program in designing a flushing system.  No attempt is made to present
any type of programmer's guide,  but  the program is documented well
enough internally to allow an analyst to make minor changes if necessary
for a  particular application.   The analytic features of  the program are
discussed in the previous sections of  this  report.

The inputs for the program may be classified as two types:  those data
describing the lateral and the various flow parameters in it> and those
characteristics of the flushing station which effect either the cost or
performance of the station.  These descriptive data plus a  specified effi-
ciency are sufficient to allow the program to determine the minimum
cost station configuration.

Before detailing the precise  form of inputs and outputs, a summary of the
assumptions  on which model is based would be  in order to assure proper
application.   The pertinent assumptions are:

  • The stations flushing efficiency may be expressed by the equations
    developed by the Central Engineering Laboratories.  The equation
    for average efficiency over the length  L using clean water as the
    flushing fluid,

                                 190

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     C
      ESS
•y;-3°°-X-4p1-8      ;
•—'	i—7	;—~	  x 10
    where
          f-*
           ESS = avera8e cleansing efficiency over a given length of
                  sewer L(%)

            V   = volume of flush (ft3)
             j*

            QF = rate of flush (cfs)

             S  = average slope of pipe (%)

             D = diameter of pipe (ft)

            Q   = rate of base flow (cfs)
             JD

             L = distance from installation (ft)

If the flushing fluid is sewage, it is necessary to apply a correction f ac •
tor to the above expression.  If ^ESS ^s t^ie average efficiency using
sewage for flushing,  the change is,
                                           ESS
                                               \
                                          100

    where

          AC ^  =  14. 3 - . 14 V_ - . 242 Q_ + . 007 11 L
             ESS                -t1          .r

 •  The efficiency (in percent of solids removed) is independent of the
    solids load in the base flow.

 •  Stations  and locations are sufficiently close together so that the
    point  efficiency  never falls below zero.

 •  Any flushing station will only have effects downstream of its
    installation.

 •  When the efficiency curves of two or more stations overlap, the effi-
    ciency at any  point is taken as  the maximum of the overlapping effi-
    ciencies taken individually at that point.

                                  191

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  •  The stations act in concert with one another.   At the least,  the
    flushing action will pass to successively downstream locations.

If these assumptions cannot be met or at least generally satisfied,  the
model should be applied with judgement.

Restrictions

There are various dimensional restrictions on the size  of the problem
that can be evaluated as the program is now written.  The number of
station types that can be considered along a lateral is limited to six.  A
station type is  as specified on a station type card  as  detailed later in
this discussion.  Locations along an individual lateral are limited to  30
sites.   A location includes  manholes and any other readily accessible
locations.  Of course,  modifications can be made to the program to  per-
mit the evaluation of larger problems.

Timing

Execution time is primarily dependent on four parameters; number of
station types, division of the limits on the volume, number of manhole
locations along the  lateral, and the starting value  of  the shadow savings.
Execution time seems to increase roughly by  the square of the number
of station types and  the division size, and linearly with  the number of
locations.  The initial value of the shadow savings influences the execu-
tion time in a somewhat linear manner but the precise effect is dependent
on the relative magnitudes  of the  initial value and  final solution value.

Whereas the number of station types and installation locations are de-
fined  by the problem and hence fixed as far as reducing  execution time,
the division limits and starting value of the shadow savings can be mani-
pulated to achieve some processing economies.  By using an arbitrary
shadow savings and  a relatively small number of divisions in the initial
stages of analysis and increasing the number  of divisions and more
closely approximating the  shadow savings during more refined analysis,
a significant reduction in computer costs can  be achieved.  There are
notes in the program as to where the modifications can  be made.

The example presented later in this appendix  required  5 minutes for
execution with  the values as defined in the program as listed.
The following is a list and explanation of the data required to execute the
program.  All numeric data are right justified and, if necessary,  carry

                                 192

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a decimal point in the appropriate position.  There are three groups of
cards:  a title card of which there is one; location cards consisting of
two cards for each manhole location along the lateral, the first of the
two cards contains lateral characteristics data and the second, data on
installation costs at the manhole; and station cards, one for each station
type detailing operational and cost data about each station.   A blank card
separates the location cards from the station type cards.

Title Card
    Card Columns
         1 - 40
       41 - 48
          50
       51 - 60
                  Explanation

Title to be printed on the output
Date computer run performed
Code indicating whether the required efficiency
or a shadow  savings value will be specified by
the analyst.

 0  or blank   required efficiency specified and
              program will automatically
              determine shadow savings

 1            shadow savings input

Required efficiency of cleansing,  CESS>  to De
attained  along the lateral in percent  or if unit
value of  shadow savings is to be  an input it is
entered in this field.
Location Cards
    Card Columns
                  Explanation
    Card 1 - Physical Characteristics
         1 - 5

         6-10



       11 - 20

       21 - 30
Lateral number of the pipe being evaluated.

Manhole number of the location under consider-
ation (number beginning at upstream end of
lateral).
Distance to next manhole or to main or inter-
ceptor in feet.
Average base flow in the reach to the next man-
hole in cfs.
                                   193

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Card Columns                       Explanation

   31-40         Average quantity of solids deposited in the next
                   reach in pounds of solids deposited per foot of
                   sewer.   This is dependent on the parameters of
                   the lateral and the frequency of flush.

   41 - 50         Diameter of pipe in feet.

   51-60         Average slope over the  reach to the next
                   manhole (%).
   61 - 63         Multiple of low volume limit yielding high volume
                   limit at this  location for station described on
                   first station type card.

   64 - 66         Multiple of low volume limit yielding high volume
                   limit at this  location for station described on
                   second station type card.

   67 - 69         Multiple of low volume limit yielding high volume
                   limit at this  location for station described on
                   third station type card.

   70 - 72         Multiple of low volume limit yielding high volume
                   limit at this  location for station described on
                   fourth station type  card.
   73-75         Multiple of low volume limit yielding high volume
                   limit at this  location for station described on
                   fifth station type card.

   76-78         Multiple of low volume limit yielding high volume
                   limit at this  location for station described on
                   sixth station type card.

Card 2  - Installation and Variable Costs

    1-5           Lateral number from the above  Physical Charac-
                   teristics card.

    6-10         Manhold number from the  above Physical Charac-
                   teristics card.

   11-14         Minimum cost installation (excluding purchase
                   cost) for station on first station type card ($).

   15-18         Variable cost for increasing volume for station on
                   first station type card ($/ft^).  The added cost of
                   purchasing and installing a flush station of a given
                   type that is larger than the minimum sized unit,
                   per cubic foot of increased volume.

                                 194

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Card Columns                        Explanation

   19-21         Exponent on volume for non-constant purchase
                   and installation costs (for station on first station
                   type card).  [These three cards define the param-
                   eters of  the installation and variable cost
                   expression.

                    Cost = minimum cost + (variable  cost)
                            x (volume - minimum volume)exponent]
   22 - 25         Minimum and variable  costs, and exponent for
   26 - 29         station on second station  type card.
   30 - 32

   33 - 36         Minimum and variable  costs and exponent for
   37 - 40         station on third station type card.
   41 - 43

   44 - 47         Minimum and variable  costs and exponent for
   48-51         station on fourth station type card.
   52 - 54

   55 - 58         Minimum and variable  costs and exponent for
   59 - 62         station of fifth station type card.
   63 - 65
   66 - 69         Minimum and variable  costs and exponent for
   70-73         station of sixth station type card.
   74 - 76
       NOTE:  If a station type is not feasible for the partic-
       ular manhole, the corresponding  field should be left
       blank or contain zeros.  If it is desired  to minimize
       only the  operation  costs, the feasible  station types
       be indicated by a 1 in the  right most position of the
       appropriate minimum cost  field;  the infeasible  types
       should, as before, be left blank.
                                  195

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Station Type Cards
      Card
    Columns

      1 - 4
        5
Field

  4
  1
6
10
16
28
- 9
- 15
- 21
- 33
4
6
6
6
     34 - 39

     40 - 45
     46 - 51
  6
  6
              Explanation

Code to identify station type.

Flushing fluid code:  0 if clean water is the
flushing agent and   1  if sewage is to be
employed.

Expected  life of the station in years.

Flushing rate of the station in cfs.

Low volume  limit in ft^ on the quantity of flush.

Frequency of flushing expressed by  the number
of hours between flushes.  Normally the fre-
quency is 24 hours.  Note that the average
solids load in the sewer will decrease as the
time between flushes (frequency)  is  reduced.

Unit cost  ($/ft^) to purchase a ft^ of flushing
agent for  operation of the  station.

Monthly maintenance cost of station ($).

Purchase cost ($) to procure a  station of this
type with  minimum capacity.
These are the inputs required to execute the program.   If more basic
data were used a preprocessor could,  of course, be programmed to
create a file which this program could then read to obtain the necessary
data.

Output

A sample output is shown near the end of this discussion.   The interpre-
tation of these forms is  straightforward, but a detailed  description is
contained herein so as to avoid any ambiguity.  On the first page the title
entered on the title card is printed  at the top of the page; the date on the
title card is also printed,  appearing below the title.  The  lateral number
entered in the first field of the Location Cards is output on the  next line.
                                 196

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    MANHOLE
    NUMBER
    STATION
    TYPE
    FLUSH
    RATE
    CFS

    FLUSH
    VOLUME
    CU FT
Identifying number of the manhole for which
the associated line indicates the installation.
This is the number indicated in the second
field of the location cards and the output list
begins at the most upstream end  and works
down the lateral.

Station type to be installed at the manhole loca^
tion indicated.  The station type number is  as
defined in the first field of the  station type
cards.

Flush  rate of the  station to be installed.  This
will be as defined in the flushing  rate field of
the station type cards.

Flushing volume required by the particular
station type to achieve sufficient cleansing.
    INSTALL
    COST
    DOLLARS

    OPERATE
    COST
    DOLLARS
Cost to install the station type specified.
Included in this is the purchase price plus the
direct cost of installation.

Monthly cost to purchase flushing fluid and
operate at the  specified frequency.
    MAINT.
    COST
    DOLLARS

    SOLIDS
    REMOVED
    POUNDS

    SOLIDS
    REMOVED
    PERCENT
Monthly maintenance costs of station.
tained from input.
Ob-
The number of pounds of solid material re-
moved over the reach to the next manhole
location.

The average percentage of solid material
removed over the reach to the next manhold
location.
There  are totals for the appropriate columns.  An average percent of
solids  removed over the entire length of the lateral is tabulated as
AVERAGE EFFICIENCY.   It is this value that is compared to the input
required efficiency to be certain of attaining  sufficient cleansing.  The
value tabulated under MAXIMUM EFFICIENCY is the maximum
                                   197

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efficiency that can be obtained independent of the cost of the system.
No cleansing efficiency greater than this amount can be attained without
increasing the maximum volume specifications.

The second page of the illustrated output contains more detailed infor-
mation on the flushing performance.  The particular cleansing efficiency
for various points along the lateral is tabulated.   The points at which
the efficiency is  calculated are:

  o  at each 100  ft along the lateral

  9  at each manhole or station location, and

  •  at any points at which efficiency curves  cross.

The first column of the output gives the distance from the most upstream
manhole.  The second column is the point flushing efficiency at the cor-
responding distance.  Also printed is the value of shadow  savings  cor-
responding to the particular report.

One report will be generated for each value of the shadow savings tested.
The program will terminate when  the required level of efficiency (in
percent solids removal) is  attained.

Error Messages

There are  no informative diagonistic messages  output by the program.
The FORTRAN and loading messages normally furnished by the computer
will still be available but no additional tests  explicitly for erroneous or
inconsistent data will be made.  Interspersed within the program are
statements of the form

                             STOP XXX.

XXX  is an integer and is unique to each STOP statement.   These state-
ments may cause the program to terminate execution for a variety of
reasons; none of which is normal.   The corrective action when a termi-
nation of this sort occurs is to locate the STOP  statement within the pro-
gram by means of the  identifier XXX (this  number will be printed  on the
output) and rectify the problem (which most likely will be  in the data) by
examining  the program logic immediately preceding the termination.

Example

The following is  presented  as a rather typical application  of the program.
For the lateral illustrated and described on the following page it is

                                198

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required to remove 70 percent of the solids.  The lateral carries the
designation 2-3  -B.   There are four possible  station types.  The
installation costs for the different types are schematically illustrated
below.  The particular specifications for the station types and manhole
locations are on the following pages.
Installation
Cost
($)
Station Type 3
                                                     Station Type 1
                                                  Station Type 2
                                                    Station Type 4
               Min.
              Volume
      Max.
     Volume
                                                          Flush Volume
  Lateral 2 - 3 -B
                                                                Main
  Length

  Diameter

  Avg.  Base Flow

  Avg.  Load

  Avg.  Slope
©
310 ft
8 in.
0026 cfs
00115 Ib/ft
.6%
©
200 ft
8 in.
. 0067 cfs
.00303 Ib/ft
.4%
GD
230 ft
10 in.
. 0102 cfs
. 00460 Ib/ft
. 32%
©
650 ft
12 in.
. 0174 cfs
. 00781 Ib/ft
.22%
                            Sample Problem
                                    199

-------
Station Type
  Flush Fluid

  Life

  Flush Rate

  Min.  Flush Vol

  Frequency

  Unit Cost

  Monthly Maint.
   Cost

  Purchase
   Location
F03C
Clean
15 yrs.
2. 00 cfs
Dl. 30 ft3
24 hrs.
. 0012$/ft3
t.
$5. 00
$1000
Variable Costs:
Component
Min. Install.
Var. Cost
Exponent
Min. Install.
Var. Cost
Exponent
Min. Install.
Var. Cost
Exponent
Min. Install.
Var. Cost
Exponent
F27C F36C
Clean Clean
10 yrs. 10 yrs.
1. 33 cfs 4.45 cfs
80 ft3 30 ft3
24 hrs. 24 hrs.
.0012$/ft3 .0012$/ft3 ,
$8. 00 $8. 00
$800 $2500

F03C F27C F36C
300 500
30 .071
.5 1.5
500 - 700
10 - .071
1.0 - 1.5
750 300 900
10 40 .071
1.0 .5 1.5
1000 300
10 45
1.0 .5
F03S
Sewage
10 yrs.
2. 00 cfs
30 ft3
24 hrs.
. 0012$/ft3
$12. 00
$1000

F03S
-
-
-
500
0
0
850
0
0
900
0
0
                                200

-------
Maximum Limit on Volume

The following table lists the maximum volume of water that can be
stored and utilized for flushing.  Normally the limit will be a function
of the size of the manhole and depth of pipe at that location; hence, the
limit must be expressed at each location for each station type.  Also
the maximum limit as  input to the program is expressed as multiples of
minimum flush volume.

Station Type
Location
1

2

3

4

Measure
cubic feet
multi. low
cubic feet
multi. low
cubic feet
multi. low
cubic feet
multi. low
F03C
-
-
65
2. 2
90
3. 0
105
3.5
F27C
240
3.0
-
-
320
4. 0
360
4.5
F36C
110
3.7
135
4.5
185
6.2
-
-
F03£
-
-
60
2.0
85
2.8
120
4. 0
 The prepared card input and final results of the computer run are found
 on the following pages.
                                    201

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1 2 3 < S E I I » 10 II lil]HI5ltinilSZl!l22;JZ
-------
                 SUMMARY — INPUT DATA
           ANALYSIS FOR LATERAL  2 - 3 - B
DATE 10/09/70

LATERAL N0.2-3-B

LATERAL CHARACTERISTICS
                DISTANCE TO
   LOCATION  NEXT MANHOLE (FT)
       -01

       -02

       -03
      310.

      20C.

      230.

      65C.
                                   REQUIRED  EFFICIENCY
     AVERAGE BASE
       FLOW (CFS)

       .00260

       .00670

       .01020

       .01740
iVERAGE BASE
LOAD (LB/FTI
.00115
.00303
.00460
.00781
AVERAGE SLOPE
m
0.600
0.400
0.320
0.220
DIAMETER
(FTI
0.670
0.670
0.630
1.000
STATION TYPE CHARACTERISTICS

   STATION CODE               F03C
   FLUSH FLUID CODE             0
   STATION LIFE (YRS)          15
   FLUSH RATE (CFS)            2.00
   FLUSH VOL-LQK ICUFTI       30.
   FREQUENCY (HRSI             24.
   MAINTENANCE COST (SI        5.0
   PURCHASE COST (t)        1000.
   COST OF HATER ($/CUFT)   .00120
                                  F27C
                                   0
                                   1C
                                   1.33
                                  80.
                                  24.
                                   8.0
                                1200.
                                .00120
                                F36C
                                  0
                                 10
                                 4.45
                                30.
                                24.
                                 8.0
                              2500.
                              .00120
                                F03S
                                  1
                                 10
                                 2.00
                                30.
                                24.
                                12.0
                              1000.
                              .0
INSTALLATION COSTS / HIGH VOLUME LIMIT
                                     STATION TYPE
   LOCATION                   F03C           F27C
    -01
    -02
    -03
    -04
MINIMUM COST
VARIABLE COST
EXPONENT
HIGH VOL MULT

MINIMUM COST
VARIABLE COST
EXPONENT
HIGH VOL MULT

MINIMUM COST
VARIABLE COST
EXPONENT
HIGH VOL KULT
  0.0
  0.0
  0.0
  0.0

5CC.OOO
 1C.000
  1.00
  2.20

75C.OOO
 10.000
  l.OC
  3.00
MINIMUM COST   1CCO.OOO
VARIABLE COST    10.000
EXPONENT          1.00
HIGH VOL MULT     3.50
300.000
 30.000
  0.50
  3.00

  0.0
  0.0
  C.O
  0.0

300.000
 40.000
  0.50
  4.00

300.000
 45.000
  0.50
  4.50
  F36C

500.000
  0.071
  1.50
  3.70

700.000
  0.071
  1.50
  4.50

900.000
  0.071
  1.50
  6.20

  0.0
  0.0
  0.0
  0.0
  F03S

  0.0
  0.0
  0.0
  0.0

500.000
  0.0
  0.0
  2.00

850.000
  0.0
  0.0
  2.80

900.000
  0.0
  0.0
  4.00
                                           203

-------
            ANALYSIS FOR LATERAL  2-3-0
DATE
10/09/7C
LATERAL NO. 2-3-B
MANHQLF STATION
NUMBER TYPE
-01 F27C
-02 NONE
-03 NONE
-04 NONE

CIENCY 67.65
CIENCY 89.22
MONTHLY MONTHLY
FLUSH FLUSH INSTALL OPERATE MAINTEN SOLIDS
RATE VCLU^E COST 'COST COST REMOVED
CFS CU FT DOLLARS DOLLARS DOLLARS POUNDS
1.33 240. 1879. 8.64 8. CO 0.356
0.436
0.836
3.186
24Q. 1879. 8.64 8.00 4.815


SOLIOS
REMOVED
PERCENT
IOC. 00
72.02
79.01
62.77




-------
            EFFICIENCY CURVE
           LOCATION             PERCENT

               0.0                100.00
             ICO.00               ICO.00
             200.00               100.00
             300.co               lac.oo
             310.00               100.00
             310.CO                76.55
             410.00                71.76
             510.CO                68.CI
             510.00                82.36
             610.00                79.2*5
             710.00                76.69
             740.CO                75.98
             74C.QO                68.72
             840.00                66.55
             940.CO                64.62
            1C40.00                62.89
            1140.00                61.31
            1240.00                59.87
            134C.GO                58.54
            1390.00                57.91
            1390.00                C.O
VALUE CF MATERIAL REMOVAL  DDL / LB               38.44
                            205

-------
PROGRAM LISTING
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c

OPTIMUM
SELECTION AND LOCATION OF PERIODIC FLUSHING STATIONS
FOR COMBINED SEWER CLEANSING


W H PALLSEN
28 JULY
OED FMC


ACOST
AEFF
AMOUNT
AREA
AVEFF
BLANK
CODE


CODE1
COST
COSTN
COSTP
COSTPT
COUNT
CRF
CR
Cl
C2
C3
C4
C5
C1I
C2I
C3I
C4I
C5I
0
DATE
UELV
DIA
EFF
EFFAVE
EFFERR
EFFHI
EFFINT
FFFLO
EFFMAX
EFFPEQ
EFFSTA
EFFTRP
EFFY
EFF1
EFF2
FREQ
GPM
ICOST
ICOSTI


1<37C



ACCUM COST OF THIS STATION - DOLLARS / MCNTH
EFFICIENCY TABLE FOP SELECTED STATION STRING
AMCLNT OF MATERIAL REMOVED BY FLUSHING
AREA UNDER EFFICIENCY CURVE - PERCENT * FT
AVERAGE EFFICIENCY FOR THIS STRING OF STATIONS
i •
CODE FDR TYPE OF PROCESSING
CODE = 1 INPUT SAVE
CODE = 2 INPLT REQUIRED EFFICIENCY
CODE FOP FIRST TIME THROUGH ITERATION CONTROL ROUTINE
COST OF STATICN - DCLLARS / MCNTH
NET CCST CF SELECTED STATICN
COST OF PURCHASE AND INSTALLATION - COLLARS
TOTAL COST CF PURCHASE AND INSTALLATION - DOLLARS
COUNT OF THE NUMBER OF ITERATIONS
CAPITAL RECOVERY FACTOR
CAPITAL RECOVERY FACTCR
COEFFICIENT C« FXPCNENT OF THE EFFICIENCY CURVE
COEFFICIENT OR EXPONENT OF THE EFFICIENCY CURVE
COEFFICIENT OP EXPONENT CF THE EFFICIENCY CURVE
COEFFICIENT OR EXPONENT OF THE EFFICIENCY CURVE
COEFFICIENT OR EXPONENT CF THE EFFICIENCY CURVE
COEFFICIENT OP EXPONENT OF THE EFFICIENCY CURVE
COEFFICIENT CR EXPONENT CF THE EFFICIENCY CURVE
COEFFICIENT OR EXPONENT CF THE EFFICIENCY CURVE
COEFFICIENT OR EXPONENT OF THE EFFICIENCY CURVE
COEFFICIENT OR EXPONENT CF THE EFFICIENCY CURVE
DISTANCE - FT
REPORT DATE
VOLUME INCREMENT FCR A FLUSHING STATION - GAL
DIAMETER OF PIPE - FT
POINT EFFICIENCY AT D FRCM STATION
AVERAGE EFFICIENCY CVEH THIS SEGMENT - PERCENT
ERRCR FACTCR FOR ZEROING IN ON EFFKEQ
EFFICIENCY ON HIGH SIDE OF REQUIRED EFFICIENCY - PERCENT
INTEGRAL CF EFF AGAINST DISTANCE
EFFICIENCY CN LCK SIDE OF REQUIRED EFFICIENCY - PERCENT
MAXIMUM EFFICIENCY ATTAINABLE
EFFICIENCY REQUIRED FOR THIS STRING OF FLUSH STATIONS
INTEGERAL CF EFFICIENCY FOR THIS STATION
EFFICIENCY AT LAST ITERATION CYCLE PERCENT
SUBROUTINE TO FIND THE EFFICIENCY CURVES
EFFICIENCY AT STATION
EFFICIENCY AT END CF SEGMENT - PERCENT
NO. OF HOURS BETV.EEN FLUSHINGS
AVERAGE BASE FLCW IN A PIPE - CU FT / SEC
INSTALLATION CCST - DOLLARS / MONTH
INSTALLATION COST CF THIS TYPE OF FLUSHING STATION AT
THIS LOCATION
206

-------
C      INC       NO  CF  VOLUMES  FCR A STATION TYPE
C      ITRP      NO  OF  ITERATION CYCLES  WHICH HAVE SAME EFFICIENCY
C      K
C      KKKGD     CODE  FOR  TYPE  CF FLUSHING WATER  0-CLEAN  L-CIPTY
C      KN4ME     2 CHAR LATERAL NAME
C      KODE      TABLE  TO  INDICATE OPTIMUM SELECTICN
c      KODET     NO  OF  THE LAST STATION  THAT GIVES LOWEST ACCUM COST   WITH
C               THIS  STATICN
C      KOOEX     NO  OF  THE STRING CF STATIONS GIVING THE LOWEST ACCUl"  COST
C      LIFE      LIFE  OF A FLUSHING STATION - YR
C      LNAME     3 CHAR LATERAL NAME
C      LOAD      AVERAGE LOAD OF DEPOSITS OVER SEGMENT  LB /  FT
C    LOAOT      TOTAL  POUNDS CF SOLIDS  OVER LATERAL
C      M
C      MAXCNT    MAXIMUM NC OF  ITERATIONS
c      MAXTRP    MAX NO. OF ITERATION CYCLES WHICH HAVE SAME  EFFICIENCY
C      MCOST     MONTHLY MAINTENANCE COST  -  DOL
c      MCOSTI    MONTHLY MAINTENANCE COST  -  COL
C      MCOSTT    TOTAL  MONTHLY  MAINTENANCE CCST - DOLLARS / MONTH
C      MNAME     2 CHAR LATERAL NAME
C      NLOC      NO  CF  LOCAT-ICNS
C      NNAME     3 CHAR LATERAL NAME
C      NSTA      NO  OF  STATIONS
C      NSTAT     NO  OF  STATIONS
C      NSTYP     NO  CF  STATICN  TYPES
C      OCOST     OPERATING COST - DCLLATS / MONTH
C      OCOSTP    COST  OF MONTHLY OPERATION - DOLLARS / MONTH
C      OCOSTT    TOTAL  MQNTHY OPERATING  CCST - DOLLARS / MONTH
C      OPT       CODE  FOR  METHCD CF CPTI MUM I ZATION
C               OPT =  1   MINIMIZE CPERATICNAL COST
C               OPT =  2   MINIMIZE TCTAL CCST
C      PCOST     PURCHASE  COST  PER MONTH - DCLLARS / MONTH
C      PCOSTI    TOTAL  PURCHASE CCST CF  A TYPE OF FLUSHING STATION - DOL
C      OF        RATE  OF FLUSH  FLCW - Cu FT / SEC
C      QFI       MAXIMLM FLUSHING FLCW RATE - CU FT / SEC
C      RATE      INTEREST  RATE  - 6 PERCENT COMPOUNDED ANNUALLY
C      SAVE      VALUE  OF  REMOVING MATERIAL  DCLLARS / POUND
C      SAVEFF    SUBROUTINE TO  SAVE THE  EFFICIENCY CURVE CF SELECT C STRING
c      SAVEHI    VALUE  OF  SHADOW SAVINGS ON HIGH SIDE OF EFFREC
C      SAVELO    VALUE  OF  SHADOW SAVINGS ON LOW SIDE OF EFFREQ
C      SAVING    SAVINGS OF SELECTED STATION
C      SHI       A HIGH VALUE FOR REMOVAL OF MATERIAL TO FIND THE
,C               HIGHEST MAXIMUM EFFICIENCY  -  DDL / LB
c      SLOPE     AVERAGE SLCPE  OF PIPE - PERCENT
C      SOLIDS    AMOUNT OF SCUOS REMOVED BY THIS STATION - LB
C      SOLT      TOTAL  AMOUNT CF SOLIDS  REMOVED - LB
C      SRP       SOLIDS REMOVED BETWEEN  LATERALS - LB
C      STYP      4 CHAR NAME FCR TYPE OF FLUSH STATION
C      STYPI     4 CHAR NAWE FCR TYPE OF FLUSH STATION
C      TCOST     ACCUM  COST FOR THIS LOCATION
C      TCOSTI    TOTAL  MONTHLY  INSTALLATION CCST  DCLLARS
C      TCOSTI    SAVE  AREA FOR  FINDING LOWEST ACCUM COST  DOLLARS
C      TITLE     REPORT TITLE
C      TMSAVE    TOTAL  MONTHLY  SAVINGS
C      TNCOST    TOTAL  NET COST
C      TOCOST    TOTAL  MONTHLY  OPERATING COST
C      UCOST     UNIT COST CF FLUSHING WATER - DOLLARS / GAL
C      UCOSTI    UNIT COST OF FLUSHING WATER - DOLLARS / GAL
C      VALUE     VALUE  OF  THE SAVINGS CAUSED BY THE INSTALLATION  OF THE
C               STATION - DOLLARS / MONTH

                                   207

-------
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
VHDUM
VH

VL

VOL
VOLT
X
XN,YN
XO.YO
XTT,YTT
XX
Z

ZMIN
ZXP
ZVAR
zz
llll

L
J
I


               DUMMY
               LARGEST  MAXIMUM  VOLUME  OF  WATER  DISCHARGED  BY  A  TYPE  OF
               FLUSHING  STATION
               SMALLEST  MAXIMUM VOLUME OF WATER DISCHARGED BY A TYPE OF
               FLUSHING  STATION
               VOLUME OF  WATER  DISCHARGED PY  FLUSHING  STATION - CU  FT
               TOTAL VOUME  GF FLUSH  TO OPERATE  EACH  MONTH
               DISTANCE  BETWEEN STATIONS  - FT
               EFFICIENCY TABLE FOP  CURRENT SELECTION  CANDIDATES
               EFFICIENCY TABLE FCR  PREVIOUS  SUBOPTiMuMIZED SELECTION
               TABLE FOR  HOLDING  THE EFFICIENCY CURVE  TEMPERARILY
               DISTANCE  FROM BEGINNING OF THE LINE
               DISTANCE  FROM STATICN AT WHICH EFFICIENCY DROPS  TO ZERO
               USE WHEN  3 AND C ARE  ZERO  - FT
               MINIMUM  INSTALLATICN  COST   - DOL
               INSTALLATION COST  EXPCNNENT
               VARIABLE  INSTALLATICN COST  -  DCL  / FT  ** EXP
               DISTANCE  FROM FLUSHING  STATION TO  ZERO  EFFICIENCY
               ACCUM COST - DOLLARS

               ROW - TYPE CF STATION
               COL - LOCATION
               TYPE OF THE  PREVICUS  STATION
C
C


C
C
      COMMON LOAD ( 3C )

      COMMON KKKOD (36)

      COMMON NSTAT,  NLOC
      COMMON    X(30),  GPM (30), OIA (30), SLOPE (30)

      COMMON XTTdOO, 36), YTT(100,36)

      COMMON    XX (31), Z(36)

      COMMON XOUOO,  31), YC(10C,31)

      COMMON XN (50,  36), YN (5C, 36)

      COMMON VOL (36,30) ,GF(36)

      REAL LOAO,LOADT

      REAL ICCSTI
      REAL ICCST
      REAL MCCSTK6), MCOST ( 31) , MCCSTT

      INTEGER KKKD (7)

      INTEGER CODE

      INTEGER OPT

      INTEGER COUNT

      INTEGER LNAME,  BLANK

      INTEGER STYPI
EQUIVALENCE (NSTA,  NSTAT)
      DIMENSION SAVING (3C)
      DIMENSION COSTN <30)
      DIMENSION KCDEX (3D

      DIMENSION SOLIDS(30)
      DIMENSION KODE (36, 30)»  ACOST (36, 30), ICOST (36, 30)
      DIMENSION             CCST (36)
      DIMENSION TITLE(IC),  DATE (2)
      DIMENSION KNAME(20),LNAME(20),MNAME(20),NNAME(20)
                                208

-------
























OIMENS
DIMENS
OIMENS
o IMENS
DIMENS
DIMENS
OIMENS
DIMENS
ION STYPK7), LIFE(7), GFI(7), VL(7),
ICN UCCSTH7) , PCCSTK7)
ION zz(7)
ICN FPEG (36) , CELV<36)
ION COSTP (36), CCCSTP (36)
ION C5K7) , ICOSTK7, 30)
ICN UCCST(36) , PCOST136), STYP(36)
ION ZMIN (6, 30), ZVAR (6, 30), ZXP (6,
DATA BLANK /• '/
C
C







C
C
C





101
1C2
103
1C4
1C8
1C9
no



201















1
2


FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT



FORMAT


3



































2C2
203
204
205
206
207
210
211
212
213
214






215
216
217
218
219

220
225
8C1
8C2
803

8C4



4











1
2
3
4
5
6





1



FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT


(8110)
(8F1C.O)
( 1CE8.01
(2(A2,A3) ,6(2F4.0,F3.0) )
( 1CA4, 2A4, IX, [1, F10.0)
(2IA2.A3) ,5F1C.C,6F3.0)
(A4, 11, 14, 7F6.C)



('I', 25X, 'MONTHLY', 4X, 'MONTHLY' /
5X, 'LOCATION STATICN', 4X, 'INSTALL'
4X, 'MONTHLY', 8X, "NET* /
11X, «NO«, 5X, 'TYPE', 7X, 'COST', 7X ,
•SAVINGS' , 7X, 'CCST' // )
(113, 19, 4F11.2)
(/// ' TOTAL MONTHLY INSTALLATION COST'
(• TCTAL MCNTHLY OPERATING CCST', 6X, F
(' TOTAL MONTHLY SAVINGS', 13X, F10.2)
(• TCTAL NET COSTS 2ox, Fio.2)
(//' AVERAGE EFFICIENCYSF10.2)
(/,' MAXIMUM EFFICIENCYSF10.2)
( ' 1' , 24X, 1CA4 //)
(13X, 'DATE' , 4X, 2A4 //)
(13X, 'LATERAL NO. ', 1 X, A2 , A3 )
(62X, 'MONTHLY', 3X, 'MONTHLY' /
FREQI<7),CR(7)






30),VH(6,30)














, 4X, 'OPERATES

•CCSTS 4X,


, 3X, F10.2)
10.2)








34X, 'FLUSH', 5X, 'FLUSH', 3X, 'INSTALL',
3X
, 'OPERATE', 3X, 'fAlNTEN', 4X, 'SOLIDS'
13X, 'MANHOLE STATION', 6X, 'RATE', 4X, •
6X
, 'COSTS 6X, 'CCST', 3X, 'REMCVEDS 3X ,
14X, 'NUMBER', 5X, 'TYPE', 7X, 'CFS', 5X,
3(
FORMAT
FORMAT
FORMAT
FORMAT
FORMAT

FORMAT
FORMAT
, 4X, 'SOLIDS' /
VOLUMES 6X, 'COST',
•REMOVED' /
•CU FTS
3X, 'DOLLARS'), 4X, 'PCUNDS' 3X, 'PERCENT' / )
( 15X,A2,A3,5X,A4,F10.2,2F10.0,2F10.2,F10.3,F10.2)
(39X,5(1X,9( '-')) / 39X,2F10.0,2F10.2,F
(15X,A2,A3, 5X, 'NCNES 50X, F10.3, F10
(2F2C.2)
CIS 12X, 'EFFICIENCY CURVE' ///
12X, 'LOCATIONS 13X, 'PERCENT' /)
(// ' VALUE OF MATERIAL REHCVAL DDL /
(15, 4(110, F15.2I)
FORMAT ('!• ,/ /,30X, 'SUMMARY — INPUT DATA'


1

1
2
3
FORMAT
FORMAT
«
FORMAT
(13X,'OATE S2A4,/)
( 13X, 'LATERAL NO. ' ,A2,A3,T60, 'REQUIRED
% ' 1 1 )
( 13X, 'LATERAL CHAR AC TER I ST ICS • ,/ , 29X, • D
10.3)
.2)



LBS F20.2 //)

,/,24X,lOA4,//)

EFFICIENCY',F4.0,

ISTANCE TOST47,
•AVERAGE BASE AVERAGE BASE AVERAGE SLOPE C I AMETER ' , / ,
16X, 'LCCATICN NEXT MANHOLE (FT) FLCW (CFS) LCAC «,

MLB/FT) ',T82,«m ST96,MFT)» )

209

-------
/,18X,A2,A3,T31,F5.C,TA9fF6.5»T64,F6.5tT80,F6.3»T<35t F5.3)
//,13X, 'STATION TYPE CHARACTERISTICS',//,^,
•STATICN CODE', T44,6(A4, 11X1)
16X, 'FLUSH FLLIC CCDE • ,T46 1 6 ( 1 1 , 1AX ) J
16X, 'STATION LIFE ( YRS) ' ( T45 ,6 ( 12, 13X ) )
16X, 'FLUSH RATE (CFS) • ,T^4 ,6 (F5.2 , IOX ) )
16X, 'FLUSH VCL-LCfc (CUFT) « ,T42 ,6 ( F5.0 T 10X ) )
16X,' FREQUENCY (HRS) ' ,T44 t6 < F3 .0 i 12X ) )
          CF WATER  (J/CUFT) • ,T42 ,6 ( F6.5.9X ) )
  805 FORMAT
  806 FORMAT
     1
  807 FORMAT
  8C8 FORMAT
  809 FORMAT
  810 FORMAT
  812 FORMAT
  813 FORMAT
  814 FORMAT (16X,'MAINTENANCE CCST  (4) • ,T43,6(F5.1,10X))
  815 FORMAT <16X,'PURCHASE CCST ($)»,T42,6(F5.o.iox>)
  816 FORMAT!   //,13X«INSTALLATICN COSTS  / HIGH  VOLUME  LIMIT',/,SOX,
     1         'STATION TYPE',/,16X,«LCCATICN',T44,6(A4,11XM
  817 FURMAT(/15X,A2,A3,T26,'KIMMUM COST • ,T40, 6 ( F9.3,6X) )
  818 FORMAT { T 26 , ' VARI ABLE CC ST ' , T
-------
c
c
c
c
c
   27 VQ (I, j) = o
      DO 580 I = lt 36
      Z
-------
   56 CONTINUE
      EFFREQ = SAVE
      SAVE = 100.C
      SAVES = SAVE
      SAVE = SHI
   48 CONTINUE
      XX (1) = C
      DO 12 J - 1, NLOC
      LOADT = LCADT + LOAD(J)*X(J)
   12 XX U+l> = XX(J) + X (J)
C
C     SET UP TABLES
C
      NSTA = 1 + NSTYP * INC
      KKKOD (1) = 0
      QF (1) =0
      FREQ (1) = FREQI (2»
      UCOST (1)^0
      PCOST (1) = C
      MCOST (1) = 0
      DQ 44 J = 1, NLOC
      VOL(ltJ) = C.
   44 ICOST I 1, J) =0
      M = 1
      00 9 I = It NSTYP
      CRF = RATE * (1 * RATE) ** LIFE(I) /  ((I + RATE)  **  LIFE(I)  -D/12
      CR( I » = CRF
      DO 9 15 = 1, INC
      M = M «• 1
      UCOST (M) = UCOSTI (I)
      KKKOO (M) = KKKO (I)
      QF (M) = QFI (I)          	
      FREQ (M) = FRECI (I)
      PCQST (M) = PCOSTI (II * CRF
      MCOST (M) = MCOSTI (I)
      DO 799 J = It NLOC
                                   VL(I))/  (INC -  1.1
                                   1.
                                   1) * DELV(J)
                                 (I, J)


                                  (I, J)  +  ZVAR  (I,  J)  *  ((15 - 1)  *
                                 17
                                 29,  28
                                 212




242
243


244


245
799


14


17

29

DELV(J) =
IF (VHU,
VOL (M,J)
IF ( 15 -
STOP 242
CONTINUE
ICOST (M,
GO TO 245
CONTINUE
ICOST (M,
DELV( J
CONTINUE
CONTINUE
DO 28 J =
IF (ZMIN
CONTINUE
ICOST (M,
GO TO 28
CONTINUE
IF (ZMIN
CONTINUE
ICOST (M,
(
J)
=
1)


J


J
) )


1
(

J


(

J
VH(I,J) * VL(I)
.LT.l.) OELV(J)
VL (II + (15
242, 243, 244


I = CRF * ZNIN


) = CRF * (ZMIN



, NLOC
I, J)) 17t 14t

) = 1E20


It J) - 11 28,

) = C

-------
   28 CONTINUE
    9 CONTINUE
   80 CONTINUE
C
c
      00 5 J = 1, NLOC
      DO 35 L = U NSTAT
      DO 6 I = 1, NSTAT
C
C     FIND THE AMOUNT OF SOLICS REMOVED BY THIS STATION
C
      IF (ICOST (L, J) - 1E18) 723, 722, 722
  722 VALUE = -1E2C
      GO TO 724
  723 CONTINUE
      CALL EFFY (i, j, L, A^CLNTI
c
C     FIND THE VALUE OF THE SAVINGS OF THIS STATION
C
      VALUE = SAVE * AMCLNT
  724 CONTINUE
C
C     FIND THE COST
C
      OCOST = UCOST (L) * VCL 
-------
   22 KODET = I
      TCOST = ACOST (It MCC)
   21 CONTINUE
      KODEX (NLCC) = KODET
      DO 23 J =  2, NLCC
      I  = NLCC - J + 1
      KODEX (I)  = KCDE (KCOET, I + I)
      KODET = KOOEX (D
   23 CONTINUE
      I  = KODEX  (1)
      COSTN (1)  = ACOST (I, 1)
      DO 24 J =  2, NLOC
      II = KODEX (J)
      12 = KODEX IJ-li
   24 COSTN CJ)  = ACOST (lit Jl - ACOST (12, J~l)
C
C     PRINT REPORT
C
   46 CONTINUE
      WRITE (6,  211) TITLE
      WRITE (6,  2121 DATE
      WRITE (6,213) KNAME(1),LKAPE(1)
      WRITE (6,  214)
      VOLT = 0
      COSTPT = 0
      OCOSTT = 0
      SOLT = 0
      MCOSTT- 0.
      DO 705 J = 1, NLOC
      M = KODEX  (J)
      IF (M - 1) 706,  706, 707
  7C6 CONTINUE
      U = 0
      DO 246 I = 1, J
      IJ = IJ +  KODEX (I )
  246 CONTINUE
      IF (IJ - J) 247, 247, 248
  247 CONTINUE
      SOLID = 0
      GO TO 249
  248 CONTINUE
      CALL SOLD  (J, KODEX(NLCC), SCLID)
  249 CONTINUE
      SRP = SCLID / LOAD (J) * 100 / X
-------
      SOLT  =  SOLT  +  SOLIU
  7C5  CONTINUE
      WRITE (6,216)  VOLT, CCSTPT,OCOSTT,MCOSTT,SOLT
      AVEFF = SOLT/LOADT * ICO.
      IF  (SAVE  - SHI)  250, 251,  251
  251  CONTINUE
      WRITE (6, 210) AVEFF
      EFFMAX=AVEFF
      GO  TO 252
  25Q  CONTINUE
      WRITE (6, 207) AVEFF
      WRITE (6,210)  EFFMAX
  252  CONTINUE
      EFFAVE  =  AVEFF
      WRITE (6, 219)
      I  = KODEX (NLCC)
      J  = 1
  253  CONTINUE
      WRITE (6, 218) XO (J, I),  YC (J, I)
      J  = J + 1
      IF  (XO  (J, I)  - IE18) 253, 254, 254
  254  WRITE (6,220)  SAVE
      IF  (SAVE - SHI) 255, 256,  256
  256  CONTINUE
      SAVE  =  SAVES
      GO  TO 8C
  255  CONTINUE
C
C     CONTROL ROUTINE FCR ITERATIONS
C
      IF  (EFFAVE - EFFTRP) 2C2,  3C1, 302
  301  ITRP  =  ITRP +  1
      IF  (ITRP - MAXTRP) 3C3, 304, 304
  304  WRITE (6, 3C5) MAXTPP, EFFTRP
  305  FORMAT  (•!', 10X,  'SAVE EFFICIENCY', 13, 2X, 'TIMES',  F20.2,
     1         'PERCENT' / '!')
      STOP  304
  302  CONTINUE
      EFFTRP = EFFAVE
      ITRP  = 0
  303  CONTINUE
      COUNT = COUNT  * 1
      IF  (COUNT - NAXCNTJ 7C3, 704, 704
  704  STOP  7C4
  7C3  CONTINUE
      IF  (CODE - 1)  69, 57, 69
   57  STOP  57
   69  IF (CODE1 - 1) 73, 70, 73
   70  CONTINUE
      IF  (EFFAVE - EFFREQ) 71, 76, 76
C  71  STOP  71
   71  CONTINUE
      SAVELO = SAVE
      SAVE  = 2 * SAVE
      EFFLO = EFFAVE
      GO TO 80
   76  CONTINUE
      CODE1 =  2
   73  CONTINUE
      IF (ABS  (EFFAVE - EFFREQ)  / EFFREC - EFFERRI 9999, 9999, 77

                                   215

-------
  77 CONTINUE
     IF (EFFAVE - EFFREC) 557, 557, 556
 557 CONTINUE
     SAVELO = SAVE
     EFFLO = EFFAVE
     SAVE = SAVELO + 0.62 * 
-------
            DISTANCE FROM
                 NCE FROM
                 NCE FRCM
            EFFICIENCY  AT
            EFFICIENCY
            EFFICIENCY
            EFFICIENCY
            EFF ICIENCY
            EFFICIENCY
                 OF THE
            LOCATION OF
                 ER FCR
            LOCATION OF
                 CF THE
                 CF THE
                 'ER FCR
                 •ER FCR
            LOCATION GF
                                   NEXT  MANHOLE
                                   NEXT  POINT  ON  SAVED  EFF  CURVE
                                   TO  ZERO  EFFICIENCY - FT
34
49
50

51
SUBROUTINE EFFY (I, J. LL, AMCUNT)

              T OF MATERIAL REMOVED BY FLUSHING
              OF EFFICIENCY CURVE FOP CURRENT CANDIDATE
              OF EFFICIENCY CURVE WHICH  IS OVERLAPPING
              NCE - FT
                       STATICN TC
                       STATION TO
                       LAST POINT
                       D
                    INCREMENT GAINED BY  ADDING THIS STATION
                    SUBROUTINE
                    AT Dl - PERCENT
                    AT C2 - PERCENT
                    AT Dl (JUST  PAST THE NEXT MANHOLE)
                     PREVIOUS STATION
                     THE STATION
                     LCCATICNS
                     THE STATION
                     PREVIOUS STATICfs
                     CURRENT STATION
                     LOCATION CF POINTS  IN THE XN.YN TABLE
                     POINTS IN THE SAVED EFF TABLE
                     THIS STATION IN THE XO,YO TABLE
            CF LOCATIONS
         EFFICIENCY TABLE FOR CURRENT SELECTION CANDIDATES
         EFFICIENCY TABLE FCR PREVIOUS SUBOPTI^UMIZED SELECTION
         INTERSECTION PCINT OF THE EFFICIENCY CURVES
         DISTANCE FRCI" START CF  THE LATERAL
         DISTANCE FROM STATION TC POINT  OF ZERO EFFICIENCY

            (30)
              (36)
            , NLOC
          X(30). GPM (3C). CIA (30), SLOPE (30)
           100, 36) , YTT(10C,36)
           X  (21) , Z(36)
           00, 31), YC(10C,31)
           50, 36) , YN (50, 36)
           (36,30),QF(36)

            LCADO
DELTX =  100
L =  I
DO 34 N  =  1,  50
YN (N,  I)  = 0
XN (N, I) = 1E19
XN (It I) = 0
LL=1 MEANS NO STATION AT  THIS LOCATION
IF (LL - 1) 49, 50, 51
STOP 49
AMOUNT = 0
RETURN
CONTINUE
DO 36 N  =  1, 100
IF (XX (J) - XO (N, D) 37, 36, 36
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c










AMOUNT
AREA
AREAQ
D
Dl
02
DA
EFF
EFFSTA
EFFVAL
EFF1
EFF2
EFF3
I
J
K
KK
L
LL
M
MM
N
NLOC
XN.YN
XOtYO
XI. Yl
XX
Z

COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON

AMI
AR
AR
01
01
Dl:
Dl
EFI
EF!
EFI
EFI
EFI
EFI
TY
LOi
COi
LOI
TY
TY
CO
CO
LO
NO
EF
EF
IN
01
01

LOAD
KKKO
NSTA
X
XTT(
X
X0( 1
XN (
VCL
REAL LOAD
REAL LOADAt
C
C




                                217

-------
   36 CONTINUE
      N = 2
   37 CONTINUE
C
C     FIND EFFICIENCY TABLE OF CURRENT CANDIDATE
C
      M = 0
      K = J
      KK = J
      KK3 = KK + 1
      MM = N - 1
      01 = XX(K) - XX(J)
  5C2 CONTINUE
      02 = XO(MM, L) - XX(J|
      IF (02) 601, 503, 503
  601 02 = 0
  5C3 CCNTINLE
      IF (J - 1) 504, 505, 5C6
  504 STOP 5C4
  506 CONTINUE
      IF (01 - 02) 505» 5C5, 5C7
  5C5 CONTINUE
      IF (01 - Z(LL) ) 508, 3C, 30
  508 CONTINUE
      CALL EFFVAL (LLf KK, Cl, EFF1)
      IF (EFF1) 521f 521, 522
  522 CONTINUE
      M = M + 1
      YN (M, I) = EFF1
      XN (M, I) = XX(J) * 01
      IF (M - 1) 515, 509, 517
  515 STOP 515
  517 CONTINUE
      IF (KK - KK3)  721, SOS. 721
  721 CONTINUE
      CALL EFFVAL (LL, KK3 , Dl, EFF3)
      IF (EFF3) 519, 519, 520
  520 CONTINUE
      IF (EFF1 - EFF3) 510, 50<5, 510
  510 CONTINUE
      M ~ M + 1
      YN (M, I) = EFF3
      XN (M, I) = XX(J) + Dl
  509 CONTINUE
      IF (J - 1) 523, 512, 524
  523 STOP 523
  524 CONTINUE
      IF (Dl - D2) 512t 511, 513
  513 STOP 513
  511 CONTINUE
      MM = W + 1
      02 = XO(MM, L) - XX(J)
  512 CONTINUE
      KK = K
      KK3 = KK + 1
      Dl - XX(K + 1) - XX(J)
      D5 = XN (M, I) + DELTX - XX  (J)
      IF (Dl - 05) 73C, 730, 731
                                 218

-------






















































c
c
c
c
c
731


730

732


3
-------
    LOADA * 0
    AREA = 0
    M = 1
 52 CONTINUE
    M = M + 1
    IF (YN(M,IM  551,  54, 53
551 STOP 551
 53 CONTINUE
    DAREA =       (YN(M-1,I) + YN(M,I)) * (XN(M,I) - XN(M-1,I») * 0.5
    AREA = AREA * OAREA
    CALL LOADX (XN(M,I), DAREA, LOADA)
    GO TO 52
 54 CONTINUE
    DAREA =       
-------
  570 CONTINUE
      CALL X1Y1 (XNIM-1,I) ,YMM-1,I),
     1           XO(K,L),YO(K,L), XO ( K, L ) ,0.0 , XN(M,I),YN(M,I), XI,Yl)
      Ml = M + i
      DO 55 155 = Ml, 50
      M2 = 5C + Ml - 155
      XN (M2,  I)  = XN IM2 - I, I)
      YN (M2,  I)  = YN (M2 - 1, I)
   55 CONTINUE
      XN (M,  I)  = XI
      YN (M,  I)  = Yl
      GO TO 560
  560 CONTINUE
      IF (YN(M,  II - YO(K, D) 561, 561, 562
  561 CONTINUE
      IF (YNIM-1, I) - YO (K-l, LM 563, 564, 564
  563 CONTINUE
      DAREO =          (YNIM-1, I) + YN(M,  I)) * (XN(M,I)  - XN(M-l,I))*.5
      AREAO =  AREAO * DAREO
      CALL LCADX (XN(M,I), DAREC, LOAOO)
      GO TO 565
  564 CONTINUE
      CALL X1Y1  (XN(M-1, I), YNIM-1, I), XO(K-1,  LI, YO(K-1, L),
     1           XO(K, L), YO(K, L), XN(M,  I),  YN(M, I),  Xl, Yl)
      DAREO =          (YOIK-I, D + YD * ui - XO
-------
    STOP  801
3C2 CONTINUE
803 FORMAT (2F20.6)
    RETURN
    END
                              222

-------
      SUBROUTINE EFFVAL (It J . D, EFF)
L
C     SUBROUTINE EFFVAL CALCULATES THE EFFICIENCY VALUES REQUIRED.
C     IF CHANGES ARE To BE MADE TO THE EQUATIONS THE CHANGES NEED
C     ONLY ENTERED HERE.  NOTE THAT THESE ARE EXPRESSIONS FOR POINT
C     EFFICIENCY WHICH HAVE BEEN DERIVED FROM THE AVERAGE EFFICIENCY
C     EXPRESSIONS SUPPLIED BY CEL.
C
      COMMON LOAD (30)
      COMMON KKKOD (36)
      COMMON NSTAT, NLOC
      COMMON    X(20), GPM (30), DIA  (30), SLOPE (30)
      COMMON XTTdOO, 36), YTT(100,36)
      COMMON    XX (31), Z(36)
      COMMON XOdOO, 31), YC(100,31)
      COMMON XN (50, 36), YN (50, 36)
      COMMON VOL (36,30),QF(36)
      REAL LOAD
      DATA ALPHA /l.O/
      DATA Al /-13.7/
      DATA    A2 X24.68/
      DATA C2 /-.OCOC711/
      DATA  BETA /1.6/
C     D        DISTANCE FRCM STATION
C     DIA      DIAMETER QF PIPE - FT
C     EFF      POINT EFFICIENCY AT D  FRCM STATION
C     GPM      AVERAGE BASE FLOW  IN A PIPE - CU FT  / SEC
C     I        TYPE CF STATION
C     J        LOCATION
C     KKKOD    CODE FOR TYPE CF FLUSHING WATER  0-CLEAN  1-DIRTY
C     QF       RATE OF FLUSH FLCW - CU FT / SEC
C     SLOPE    AVERAGE SLCPE OF PIPE  - PERCENT
C     VOL      VOLUME OF WATER DISCHARGED BY FLUSHING STATION - CU FT
      IF (D) 7, 7, 9
    7 EFF = 100
      RETURN
    9 CONTINUE
      A3 = VOL(I,J1 **1.3 * QF(I) **  0.9 * SLOPE(J) **  1.4 * 1E4 /
     1     GPM(J) ** 1.2 * CIA(J) **  1.8
      EFF = Al + A2 * ALCG1C  (A3  / 0  ** BETA) - BETA *  A2 / ALCG (10.C)
      EFF = AMIN1 (EFF, 100.C)
      IF (KKKCDU ) ) 1, It 2
    1 RETURN
    2 CONTINUE
      C1=10C - 14.3 + ,14*VCL(I,J) +  .242*CF(I)
      Cl = Cl / ICC
      EFF = 6FF * (C1 + C2 * D ** ALPhA *  (1 +  ALPHA))  *
     1            (BETA * C? * A2 * ALPHA * 0 ** ALPHA/ ALOG(IO.O))
      EFF = AMIN1 (EFF,  1CO.C)
      RETURN
      END
                                   223

-------
SUBROUTINE SAVEFF 
-------










c
c
c





550

59




553





58
X1"T (M, N)
YTT (M, N)
CONTINUE
N = 0
CONTINUE
N = N * 1
YTT (N, 1)
XTT (N, i)
IF (XC (N,
CONTINUE

FIND LOCAT

DO 78 N =
IF (XN(1 ,
CONTINUE
S
=




=
=
I )


ION

1,
I )

XTT (N, LLL)
YTT (N, LLL)



C
C
C




















78

79







535


536

537

763

538

541

543


CONTINUE
N = 2
CONTINUE

FIND HIGH

M = 1
MM = C
K = N - 1
IF (YN(M,
CONTINUE
LOWYN = 1
GO TO 537
CONTINUE
LOW'YN = 2
CONTINUE
»1M = VI* +•
CONTINUE
IF (XNIM,
CONTINUE
IF (YN(M,
CONTINUE
IF (LOWYN
CONTINUE
CALL X1Y1
1




1E19
0




YO (N, I)
XO (N, I )
- 1E16) 59, 64»


IN XC.YO TABLE

100
- XO (N, LI) 79,

= XO (N, L)
= YO 
-------
    YT(MM) = YN(M, I )
    K = K «• 1
    M = M + 1
    LOHYN = 2
    IF   764,  761,  971
971 IF (XQ(K-1,L) - XO(K,L)  * 1.00001)  761, 761,  771
771 STOP 771
761 CONTINUE
    IF (XT(MM - 1)  -  XXINLCC  + lit  775, 773,  773
775 CONTINUE
    K = K * 1
    GO TO 763
762 CONTINUE
    CALL XlYl (XO(K-1,L) ,YC(K-1,LI, XN(M,I),0.0,  XN(M,I),IOC .0,
   1           XO(K,L) ,VO(K,L) , XI,Yl)
    IF (YN(M, I) - Yl) 541,  541, 542
748 CONTINUE
    IF (YO (K, D)  754, 755,  758
758 IF (YN (M, I))  759, 751,  752
759 STOP 759
754 STOP -754
755 CONTINUE
    XT (MM) = XN (M,  I )
    YT (MM) = YN (M,  I )
    IF (XT (MM)  - 1E18) 757,  749,  749
757 MM = MM + 1
    M = M * 1
    GU TO 755
756 CONTINUE
    IF (XN(M-1,I) - XN(M,IM  762,  765,  972
972 IF (XN(M-1,I) - XN(M,I)  * 1.000Q1)  765, 765,  772
772 STOP 772
765 CONTINUE
    IF (XT(MM - 1)  -  XX(NLOC  * D)  774, 773,  773
774 CONTINUE
    M = M + 1
    GO TO 763
                               226

-------
  764
  773
  749
C
C
C
60
62
   CONTINUE
   CALL X1Y1
   IF (Yl - YO IK, Lij 541,
   Xt (MM) = XX (NIOC * ll
   YT (MM) =0
   CONTINUE
SAVE THE BETTER
                        M-l,llf XO(K,L),0.0,
                        I), XI,Yl)
                         541, 542
                              TABLES
                                                        .    , ,
                                                   X0(K,L),100.0,
      MM = 0
      K = N •• 1
      CONTINUE
      MM = MM * I
      K •= K t 1
      XTT IK,  LLLI « Xt IHMI
      YTT (K,  LLLI - YT lf»P|
      IF (YT(MMH  62, 6l» 6fc
      WRITE (6,  1011 UTlIlt YTU),
            (6,  1021 J» LtL» L



                          63» 65
                                  I, MHI
1C1
1C2
61

65
64
63


68



FORMAT 1
FORMAT (
CONTINUE
IF (LL -
STOP 65
RETURN
CONTINUE
00 67 LL
1 « 0
CONTINUE
1 = 1*
X0( I,LL»
Y0( 1,LL»
2F20.2I
31201

NSTAT)






64*



» 1, NSTAT


1
- XTtt
- YTTJ



I,LLI
ItLLI
      IF (XQ(ItLL)
   67 CONTINUE
      RETURN
      END
                - 1E18) 68, 68, 67
                                    227

-------
SUBROUTINE X1Y1 (XAl, YA1, XRl,  YB1,  X62,  YB2,  XA2,  YA2,  XI,  Yl)
c
c
c
c
c
c
c





















554

574

576
575

577


MA
MR
XAl,
XA2,
XB1,
XH2,
XI, Y
REAL
IF <
CONT
IF (
CONT
IF (
STOP
CONT
IF (
CONT
XI =
Yl =


YAl
YA2
Y81
YB2
I
MA,
XB1 -
INUE
XA2 -
INUE
XAl -
576
INUE
YAl -
INUE
XAl
YAl
SLOPE
SLCPE
FIRST
SECOND
FIRST
SECCND
OF
OF
PGI
PC
POI
LI
LI
NT
NE A
NE B
OF L
INT CN
NT
ON L
POINT CN
INTERSECT
MB
XB2)

XAl)

XB1)


YA2)




553

572

576


578



ICN PCI

,

,

,


t




554,

574,

575,


577,





INE A
LINE A
INE B
LINE B
NT CF LINES A & B

553

572

576


578



GO TO 579



578


CONT
XI =
Yl =
INUE
XAl
YB1















GO TO 579



572


CDNT
XI =
Yl =
INUE
XB1
YAl


* (YA2






- YAl) *


(XI - XA1I / (XA2 - XAl)
RETURN




553

552

CONT
IF (
INUE
XAl -

XA2)

550

,

552,

550
CONTINUE
XI =
XAl





GO TO 555









550



571

555

579
CONT
MA =
MB =
IF (
CONT
XI =
CONT
Yl =
CONT
INUE
( YA2
( YB2
MA -
INUE
( YB1
INUE
YB1
INUE

- YAl
- YB1

» /
) /
MB) 571,

- YAl

+ (YB2


*


(
(

XA2 -
XB2 -

XAl)
XB1)
577, 571

MA



* XAl - MB * XB1) / (MA - MB)

- YB1) *




(XI - XB1 ) / (XB2 - XBl)

RETURN


END






                          228

-------
SUBROUTINE XOYO (I, J)
COMMON LOAD (30)
COMMON KKKOD  (36)
       NSTATt NLOC
           X(30). GPM  (30) ,  DIA  (301i
       XTTllOCt 36),  YTT(100,36)
           XX  (31) ,  2(36)
       X0(100,  31) ,  YC(1CC,31)
       XN  (50,  36) ,  YN  (50f 36)
       VOL (36,3C),QF(36)
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
REAL  LOAD
WRITE  (6,
FORMAT  ( •
RETURN
END
                     SLOPE  (30)
           1)  I,
           XCYO1,
J, XC(I,J),
 2110, 2F2C,
YO(I,J)
6)
                                 229

-------
SUBROUTINE XNYN (I, J)
COMMUN LOAD (3G)
       KKKOD (36)
       NSTAT, NLOC
          X(30), GPM  (301 t 01 A  ( 30) ,
       XTT(IOC, 36),  YTT{100.3&)
          XX Ol), Z(36)
       X0(100, 31)t YC(1CC,31)
       XN (50, 36), YN  (5C, 36)
       VGL (36,30),GF(36)
COMMON
COMMON
COMKCN
COMMON!
COMMCN
COMN-ON
COMMON
REAL LCAD
WRITE (6,
FORMAT (•
RETURN
END
SLOPE (30)
          1 )  I , J, XN( I , J), YN  (I,  J)
          XNYN', 2I1C,  2F20.6)
                           230

-------
SUBROUTINE AREOX (K, U AREAG)
COMMON LOAD (30)
COMMON KKKOD (36»
       NSTAT, NLOC
          X(30), GPM (30). DIA  (30).
       XTT(ICO. 36), YTT(1CO,36)
          XX (31) i  Z(36)
       XOdOO,  31)
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
COMMON
REAL LOAD
WRITE  (6.
FORMAT  ('
RETURN
END
                              SLOPE (30)
             YC(10C,31)
XN (5C, 36) , YN (50, 36)
VOL (36.30) ,QF(36)
          1) K,  L,  XC(K.L).  YO(K,L).
          AREAO'.  2110.  3F20.6)
                              AREAO
                               231

-------
c
c
c
c
c
c
SU3RUUTINE LCAOX (XXX, AREA, LCACA1

AREA     AREA UNDER EFFICIENCY CURVE - PERCENT * FT
LOAD     AMOUNT OF DEPOSITED MATERIAL - LB / FT
LOACA    AMCLNT OF MATERIAL REMOVED - LB
XXX      LOCATION OF RIGHT HANC END CF AREA SEGMENT

COMMON LOAD (30)
COMMON KKKOD (36)
COMMON NSTAT, NLOC
COMMON    X(30), GPP (30). DIA (30), SLOPE (30)
COMMON XTT(100, 36), YTT(100,36)
COMMON    XX (31), Z(36)
COMMON XOC100, 31), YC(lCCt31l
COMMON XN (50, 36), YN (50, 36)
COMMON VCL (36,30) ,GF(36)
REAL LOAD
REAL LCADA
DO 1 I = 1,
IF (XXX - XX<
CONTINUE
I = NLOC
J = I
LOADA = LOADA
RETURN
END
                  NLCC
                     1) )
                      AREA * LCAO (J) * 0.01

-------
c
c
c
c
c
c
      SUBROUTINE  SOLD  (Jt  ft  SCLID)
J
M
XOYO
SOLID

COMMON
COMMON
COMMON
COMMON
COMMON
CCMMCN
COMMCN
COMMON
COMMON
LOCATION
NO OF THE EFFICIENCY CURVE
EFFICIENCY CURVE
AMOUNT OF SCLIDS CN THIS REACH
-  LB
             LOAD  (30)
             KKKCD  (36)
             NSTAT,  NLOC
                 X(30),  GPM  (3C),  DIA (30),  SLOPE  (30)
             XTT( ICC,  36) ,  YTT(10C,36)
                 XX  (31) ,  Z(36)
             X0(100,  31) ,  YC(10C,31)
             XN  (5C,  36) ,  YN  (5C, 36)
             VCL  (36,30) ,QF(36)
REAL LCAD

SOLID = 0
DO 1 I =  1,  ICO
IF (XC ( I , M) -  XX  ( J) )  1,  1 ,  2
CONTINUE
STOP 7788
CONTINUE
DAREA = (XO(I,M)  -  Xo
SOLID = SOLID +  DAREA
IF (XC (I, P ) -  XX  ( J
1 =  1 + 1
GC TO 2
CONTINUE
RETURN
END
                               l.M))  * (YO(I-1,M)
                               LCAD (J)  * 0.01
                               1) )  3, 4, A
                                    Y0( I,M)) * 0.5
                                    233

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1
Accession Number
w
2

Subject Field & Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
    Organization
                 FMC Corporation, Santa Clara, California
                 Central Engineering Laboratories
    Title
           A FLUSHING SYSTEM FOR COMBINED SEWER-CLEANSING
10

22
Authors)
Monroe, Darrell W.
Pelmulder, John P.
i i Project Designation
£irA, WwsU Contract INO. J.*±-l^-iibb
<
21 Note

Citation
 23
Descriptors (Starred First)

     "'Deposited Solids, *Combined Sewers,  ^Lateral Sewers,  Storm Water
      Overflows, Pollutional Material
 oc  Identifiers (Starred First)

          -''Periodic Flushing, Average Cleansing Efficiency, Solids Removal
 27   sr c  Because solids deposits in lateral sewers are considered to contribute a sig-
nificant quantity-of pollutional material to storm water overflows from combined sewers,
the use of a periodic flushing operation was evaluated as a means of maintaining lower
levels of  these deposited materials during low-flow,  dry weather periods.

Full scale tests were conducted on two variable-slope test sewers (IE-and 18-inch diam-
eters).  During the  tests,  solids were first allowed to build up in both test sewers by
passing domestic sewage  through the sewers for durations of  12 to 40 hours and then
were removed by hydraulic flushing.  The results from the  tests showed that flush waves
generated using flush volumes ranging from 300 to 900 gallons at average release rates
ranging from ZOO to 3000  gpm were found to remove  from 20 to 90 percent of the solids
deposited in the 800-foot long test sewers.
The cost  of installing a periodic flushing system in a typical system of lateral sewers
was estimated to be $620  to $1, 275 per acre.

This report was submitted in fulfillment of Contract  Number 14-12-466 under the
sponsorship of the Environmental Protection Agency.                  >
Abstractor
                                                      "U.S. GOVERNMENT PRINTING OFFICE: 1972-484-484'161 1-3
                                            235

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