EPA-R2-73-270
                       Environmental Protection Technology Series
 July 1973
 PRESSURE SEWER  DEMONSTRATION

AT THE BOROUGH OF

 PHOENIXVILLE, PENNSYLVANIA
                                 Office of Research and Development


                                 U.S. Environmental Protection Agency

                                 Washington, D.C. 20460

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            RESEARCH REPORTING SERIES
Research reports of the  Office  of  Research  and
Monitoring,  Environmental Protection Agency, have
been grouped into five series.  These  five  broad
categories  were established to facilitate further
development  and  application   of   environmental
technology.   Elimination  of traditional grouping
was  consciously  planned  to  foster   technology
transfer   and  a  maximum  interface  in  related
fields.  The five series are:
                     *.

   1.  Environmental Health Effects Research
   2.  Environmental Protection Technology
   3.  Ecological Research
   U.  Environmental Monitoring
   5.  Socioeconomic Environmental Studies

This report has been assigned to the ENVIRONMENTAL
PROTECTION   TECHNOLOGY   series.    This   series
describes   research   performed  to  develop  and
demonstrate   instrumentation,    equipment    and
methodology  to  repair  or  prevent environmental
degradation from point and  non-point  sources  of
pollution.  This work provides the new or improved
technology  required for the control and treatment
of pollution sources to meet environmental quality
standards.

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                                                   EPA-R2-73-270
                                                   July 1973
            PRESSURE SEWER DEMONSTRATION AT THE

          BOROUGH OF PHOENIXVILLE,  PENNSYLVANIA
                              by

                         George Mekosh
                         Daniel Ramos
                     Project No. 11050 FOU
                        Project Officer


                        James F. Kreissl
            U.S. Environmental Protection Agency
           National  Environmental Research Center
                   Cincinnati, Ohio  45268
                         Prepared  for

              OFFICE  OF RESEARCH  AND  MONITORING
            U.S. ENVIRONMENTAL PROTECTION AGENCY
                    WASHINGTON, D. C.  20460
For sale by the Superintendent of Becflfaents, U'.S.,G
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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 of the Environ-
mental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for
use.
                                ii

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                            ABSTRACT
A site was selected at the Borough of Phoenixville, Pennsylvania,
which provided a maximum variable exercise of a pressure sewer
system.  The site consisted of five residences spread over more than
one-half mile in hilly and predominantly shale-based terrain.  The
residences varied from a small house to a multiple-unit apartment
house.  The apartment house is more than half a mile in distance
and 60 feet in elevation below the existing conventional gravity
sewer inlet point.

The project proved over a six-month period that a multiple residence
pressure sewer system can adequately store peak loads of wastewater
and grind and pump wastewater through small-diameter plastic pipe
to the existing conventional gravity sewer.  During the project,
data was collected which provided information concerning the in-
stallation, operation and maintenance of the system, its technical
performance, the variations in that performance during the six-
month period and the characteristics of the wastewater as delivered
to the existing gravity sewer.

This report was submitted in fulfillment of Project Number 11050
FOU under the sponsorship of the Office of Research and Monitoring,
United States Environmental Protection Agency by the Borough of
Phoenixville, Pennsylvania
                                iii

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                             CONTENTS



SECTION                                                 PAGE

I    CONCLUSIONS                                          1

II   RECOMMENDATIONS                                      3

III  INTRODUCTION                                         5

IV   PROJECT OBJECTIVES                                   7

V    SYSTEM LOCATION                                      9

VI   GENERAL PRESSURE SEWER COMPONENT                    11
     DESCRIPTION

VII  PHOENIXVILLE SYSTEM DESCRIPTION                     17

VIII DEMONSTRATION RESULTS                               33

IX   ACKNOWLEDGEMENTS                                    57

X    APPENDICES                                          59

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                               FIGURES
1    AREA MAP OF PHOENIXVILLE

2    TYPICAL INSTALLATION

3    MOYNO FS-44 PUMP CHARACTERISTICS

4    PUMP STORAGE GRINDER INSTALLATION

5    PRESSURE SEWER SYSTEM - PHOENIXVILLE

6    PIPE AND UNIT LAYOUT

7    HYDRAULIC GRADE DIAGRAM

8    PSG AND SYSTEM USE PROFILES

9    DISCHARGE PRESSURE PROFILE OF PSG #3

10   DISCHARGE PRESSURE PROFILE OF PSG #4

11   TEMPERATURE PROFILE OF FLUID FLOWING THROUGH
     DATA STATION

12;  TEMPERATURE PROFILE OF PSG #3

13   TEMPERATURE PROFILE OF PSG #4
PAGE

 10

 12

 13

 18

 19

 20

 22

 37 Thru 42

 45

 46

 48


 49

 55
                                vi

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                              TABLES



                                                                PAGE

1    PERFORMANCE DATA LIST                                       26

2    COSTS OF HOUSEHOLD RELATED EQUIPMENT FOR                    29
     THE PHOENIXVILLE PRESSURE SEWER SYSTEM

3    COSTS RELATED TO THE PHOENIXVILLE                           30
     PRESSURE SEWER MAIN

4    COSTS RELATED TO DATA COLLECTION                            31

5    PSG USE CHARACTERISTICS                                     34

6    PSG OPERATING TIME PER CYCLE                                35

7    PSG AVERAGE OPERATING TIME PER DAY                          36

8    COMPUTER ANALYSIS                                           44

9    WASTEWATER CHARACTERIZATION                                 51, 52

10   UNIT OPERATING COST                                         53
                               VII

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                            SECTION I

                           CONCLUSIONS
1.   The primary conclusion is that the project demonstrated over a
     six-month period that a multiple-residence, separate pressure
     sewer system can adequately store peak loads of household waste-
     water, comminute solids in the wastewater and pump this waste-
     water through small-diameter plastic pipe to the existing con-
     ventional gravity sewer.

2.   The Pump Storage Grinder (PSG), which is the principal component
     of the pressure sewer system, easily handled the wastewater loads
     imposed on it at the five locations, representing a diverse
     sampling of home wastewater usage and location from the sewer
     main.

     All five PSG units operated satisfactorily including  the  two
     units located at the bottom of the hill which pumped waste to
     the main gravity sewer located % mile away and 60 ft. higher
     in elevation.

3.   The pressure sewer system operated in an anaerobic (septic)
     mode with zero oxygen levels.

4.   The project demonstrated the ease of installation of the
     pressure sewer system, including the PSG.  The pressurized
     main was installed at a cost of less than $3.00 a linear
     foot.  Operating costs averaged less than 500/month per living
     unit.  The initial cost at each household installation, which
     included the storage tank, PSG, electrical and mechanical
     connections was $2050.  This represents an average of approx-
     imately $850 per living unit (5 homes, 7 apartments).  The
     cost of future installations will depend on their size, soil
     characteristics, existing systems, cost of labor and materials,
     type of equipment and options selected, etc.
                               -1-

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                            SECTION II

                          RECOMMENDATIONS
It is recommended that, as a result of this demonstration,  pressure
sewer systems of this type be eonsidered for use as an additional
tool in the formulation of total sewerage system plans.  In addition,
it is recommended that additional cost factors for pressure sewers of
this type be developed by expanding the demonstration at Phoenixville,
including evaluation of its effects, if any, on the existing treat-
ment plant.

The following recommendations arose from field experience:

     (a)    Provide an overflow sensor connected to a visual/
            audible alarm in the house to alert the occupants
            of PSG or system malfunction.

     (b)    Grade the vicinity of the storage tank such as  to
            preclude the entry of surface water and run off into
            the tank.
                                -3-

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                           SECTION III

                          INTRODUCTION
Pressure sewer systems are attractive for use in new housing or
industrial complexes where their installation costs can be traded
off against those of conventional sewers, or at existing sites
where septic tanks have become overloaded or operate inefficiently
and require either new tanks or the installation of sewers.  Pressure
sewers become even more attractive where hilly terrain makes con-
ventional sewers extremely costly.  Several locations in the
Phoenixville area provided examples of the latter two cases.

This project afforded the opportunity to evaluate a pressure sewer
system through actual field operation by connecting several homes to
the terminus of the gravity sewer which was located uphill from
the homes.  The basic system design approach was to install a pump
storage grinder unit in a holding tank at each dwelling and con-
nect these to a branch pressure sewer line which tied into the exist-
ing gravity sewer.  The farthest site from the gravity main was %
mile away and it was 60 feet below the gravity main.

The General Electric Co. had designed a pump storage grinder (PSG)
and was field testing one engineering prototype when the opportunity
to design a pressure sewer serving multiple residences arose.  The
PSG comminutes solids in the wastewater, so that the mixture can be
pumped thru smaller diameter pipe than is possible with conventional
sewage pumps.  The pump can deliver moderate flow against relatively
high dynamic pressures (30-40 psig).  Because the PSG is installed
in a holding tank, the pump need not deliver the high flow rates
required to keep up with high capacity flows such as toilet flushing.
For this application, the pump selected delivered 15 gpm at zero
head.  Other capacities can be utilized depending on the application
and system design.
                                -5-

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                            SECTION IV

                        PROJECT OBJECTIVES
The objectives were to demonstrate over a six-month period, the
feasibility of a multiple-unit, small-diameter pressure  sewer system.
It was required to determine if the PSG unit could adequately store
peak loads of wastewater until processed and grind and pump this
wastewater through small—diameter plastic pipes up to a discharge
elevation of 60 feet into a conventional gravity sewer.   The
project provided an opportunity to make modifications based on field
requirements and to obtain operating data for future system improvements.
This was to be accomplished by recording a variety of parameters
along a time base and by collecting samples of the wastewater for
analysis and characterization.
                                -7-

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                            SECTION V

                         SYSTEM LOCATION
A group of five residences located along Pennsylvania Highway #113,
on the northern part of the Borough of Phoenixville was chosen as
the test site as shown in Figure 1.  A terminus of the gravity sewer
was conveniently located above the first residence.  The homes were
spread out over a one-half mile section, with the lowest home being
approximately 60 feet below the gravity sewer terminus.  These homes
had been utilizing septic tanks, which provided a suitable backup
system to the proposed pressure sewer.

Other considerations for selecting this site were as follows:

1.   The ground was mostly shale and percolation relatively poor.

2.   The terrain was hilly, thereby making use of conventional
     gravity sewer systems impractical.

3.   Sewers were needed immediately.  However, the road was scheduled
     for filling and widening within the next few years.  Any sewers
     installed would have been, in some areas, under 60 feet of fill
     within a few years, making access and maintenance very difficult.
     This would have required new sewers to be installed along with
     the road modifications.  The problem was solved by using a
     pressure sewer since the major equipment cost, the Pump Storage
     Grinder (PSG), could remain intact with the house while the
     plastic pipes could be replaced very inexpensively along with
     the road modifications.

4.   A recreational park along the river's edge was planned for this
     area.  A pressure sewer appeared to be the only feasible means
     of getting sewage from the lowlands adjoining the river to the
     existing sewer.  This addition could be combined with the
     existing pressure sewer system.
                               -9-

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FIQURE 1.
              PHDENIMILLE, PA.
-10-

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                            SECTION VI

            GENERAL PRESSURE SEWER COMPONENT DESCRIPTION
A typical pressure sewer system installation is shown in Figure 2.
The existing house wastewater line is diverted from the septic
tank to the Pump Storage Grinder (PSG).  The existing septic tank
is utilized as an overflow/emergency tank.  The PSG and all piping
are installed below the frost line to prevent freezing during winter
operation.  An access area is provided around the unit to allow for
servicing and maintenance.  A cover is placed over the access hole.

1.   Pump Storage Grinder (PSG)

     A sketch and additional details on the Pump Storage Grinder
     are contained in Appendix A.  The unit operates in the
     following manner.  A simple, rugged, diaphragm pressure
     switch serves as the primary control element.  The closure
     of this switch energizes a relay which starts the motor,
     thereby starting the pump and the grinder.  Water and solids
     pass through the grinder, where the solids are reduced to
     sizes less than % inch, and then into the pump inlet line,
     through the pump, through a check valve, and into the dis-
     charge pipe.  The check valve prevents back-flow from the
     pressurized main when the pump is not operating.  As the
     water level drops while the tank is being emptied, the
     pressure switch is opened causing a relay to shut off the
     unit.

     a.   Motor

          The motor is manufactured by the General Electric Company,
          General Purpose Motor Division, Fort Wayne, Indiana.  It
          is described as a 1725 RPM, 1 HP, capacitor start, double
          shaft, drip-proof motor with built-in thermal overload
          protection.

     b.   Pump

          The pump is a MOYNO Model FS-44 and is manufactured by
          Robbins and Myers of Springfield, Ohio.  This is a pro-
          gressing cavity pump' with a hardened, corrosion-
          resistant rotor operating in a resilient stator.  This
          pump has nearly vertical and linear flow characteristics
          as approximated in Figure 3 from data provided by the
          manufacturer.
                                -11-

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                                                  EXISTING VENT
CO
I
                       EXISTING GRAVITY
                       SEWAGE PIPING
                                                      .CONTROL BOX

                                                        -COVER
                                                                                               .TERRAIN
                                                                                          PRESSURE SEWER
                                                                                              PIPING
                                                                                    DRAINAGE  FIELD

                                                                                   EXISTING SEPTIC
                                                                                   TANK/OVERFLOW
                                                                 OVERFLOW LEVEL SENSOR

                                                               ON-OFF LEVEL SENSOR
ISTING GRAVITY SEWER
                                               FIGURE  2.  TYPICAL INSTALLATION

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a
s
CO

CO
w
u

a
o
       20
       10
       0
                                                     PUMP  SPEED:




                                                      1725 RPM
                                 10           15




                               FLOW RATE - GPM



                        FIGURES..  PUMP CHARACTERISTICS
20

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Grinder
The grinder is very similar in operation to a standard
household garbage disposal.  It is directly driven by
the motor at a speed of 1725 RPM.  The flywheel is
streamlined, i.e., all contours are smooth and the
impellers (choppers) are reduced in size and made an
integral part of the flywheel.  This flywheel design
at the above speed results in a sizeable reduction of
viscous drag and operating power.  Twenty-one separate
materials have been successfully tested without stalling
or damaging the grinder.  The following general comments
can be made:  (1) The materials were handled at widely
different rates.  (2) Floating materials enter the
grinder as the liquid surface drops to the level of the
suction bell, (3) dense materials tend to settle to
the bottom of the tank, (4) plastic film, rubber and
cloth are worn away at rates which prevent cumulative
build ups, and (5) mixtures of materials tend to be
ground more readily than single items.  Some of the
tested materials include:   toilet tissues, paper
diapers, wooden pencils, plastic bags, plastic plates,
and cups, sanitary napkins and elastomeric contra-
ceptives.

Check Valve

                              The very nature of wastewater,
                              i.e., its high solids content
                              including stringy and fibrous
                              materials, makes the reliable
                              closure of a check valve
                              extremely difficult.  The
                              check valve used in the pump
                              storage grinder unit was
                              selected with this in mind.
                              The valve selected was a 3/4
                              inch bronze swing type,  model
                              number 0630, made by the
                              Fairbanks Company.  Its success-
                              ful operation is largely
                              dependent on the following
                              subtle details:  (1) the hinge
point location with respect to the center of gravity of the
swing disc, (2) the mass of the swing disc, (3) a smooth seat,
(4) a self-aligning closure, (5) the eccentric body housing
which provides a pocket for the swing disc when the valve is
fully open, (6) oversize low friction passageways, and (7)
an extra smooth and clean interior configuration.
0630 Sectional
                   -14-

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   e.    Relief

         A pressure  relief valve  installed between the pump and
         the  check valve  is  intended  to prevent damage to the pump
         in the  event  of  a system blockage.  The relief valve is
         set  to  open between 70 and 75 psig  allowing  flow back
         into the  storage tank.   In order to minimize the effects
         of solids,  the valve is  mounted on  a tee above the normal
         flow line.  This prevents accumulation of solids in the
         area of the relief  valve during normal unit operation.

    f.    Control Box

         The  control box  is  a customized electrical junction box
          which provides an environmental enclosure  for  joining  the
         external  power to the motor  circuit.  It can include the
         motor start capacitor, transfer relay used with the
         differential  pressure switch, manual shut-off switch,
          instrumentation  connections, etc.
2.   Tank
    The recommended storage tank is  concrete  and  provides a reservoir
    to store peak inflows until they canbe ground and pumped out.
    The storage tank can be located  so that an  existing  septic tank
    can be used as an overflow during emergency situations, such
    as electrical power failures. A tank 30  inches  in diameter with
    a minimum depth of 36 inches below the overflow line has been
    selected as being compatible with a worst case minimum pumping
    rate of 8 gallons per minute (gpm) for any  one PSG.  The tank
    mentioned above can store 95 gallons of wastewater before over-
    flowing into the septic tank. A 30-inch  diameter storage tank
    equipped with a 7-inch differential level switch can store approxi-
    mately 45 gallons of wastewater  before actuation occurs.  Upon
    actuation, the PSG will pump out approximately  20 gallons of
    wastewater before shut off, leaving a 25  gallon  residual.  The
    tank depth can be increased if a larger storage  capacity is
    desired.  The differential between actuation  and shut-off can
    also be increased, if desired.
3.  Pipe
    Polyethylene pipe is considered to be ideal for  both lateral
    and main sewer lines.  All fittings and valves would then be
    polyethylene.  This material produces a tough, flexible pipe
    which has excellent chemical resistance to  a wide range of
                              -15-

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3.  Pipe (Cont'd)

    corrosive fluids such as sodium hydroxide, hydrochloric acid,
    sulfuric acid, etc.  Polyethylene is flexible enough to be
    plowed in.  "Plowing-in" refers to the process that combines
    trenching, feeding of coiled tubing or cable from a spool into
    a trench and backfilling all in the same operation.  This
    process makes it possible to rapidly bury long lengths of pipe
    in a trench.

    Polyethylene, schedule 40, two-inch pipe has a design pressure
    rating of 125 psig.  The pipe may be cleaned in the event of
    blockage by flushing with chemicals, with high pressure water or
    by the introduction of a "rotating snake".  A suitable alternate
    pipe is polyvinylchloride (PVC).  This has the same desirable
    characteristics  as polyethylene except it is not as flexible.
    PVC is not flexible enough to be coiled, therefore, it is not
    compatible with the "plowing-in" operation.  The choice of pipe
    material depends on the terrain, distance and availability of
    '' plowing-in'' equipment.
                               -16-

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                             SECTION VII

                    PHOENIXVILLE SYSTEM DESCRIPTION
 Five residences were involved in the project.   A storage tank with
 a Pump Storage Grinder installed in it,  was interposed in each
 existing building sewer line at a convenient location between the
 residence and the septic tank.  The existing septic tanks were used
 as emergency storage tanks in the event  of overflows  from the PSG
 tanks.  The PSG outlets were fed into the pressure main, more than
 one half mile in.length with a 70 -foot  elevation differential
(the lowest point in the system is 10 feet below the last home),
 which discharged to the existing gravity sewer.  A bypass line was
 routed through a data collection station.  Data cable was installed
 along with the pressure piping and connected each PSG and sensor
 to recording equipment in the central data station.  The PSG units
 and all piping were installed below the  frost  line at a depth of  30
 inches.  The installation required approximately 2800 feet of 2-inch
 and approximately 700 feet of 1%-inch PVC pipe, 5 pump storage grind-
 er units, and 5 storage tanks.  Also included were electrical and
 mechanical tie-ins to existing facilities.  Approximately 3000 feet
 of 52 pair data cable and approximately  500 feet of 13-pair data
 cable were also installed.

 The electrical work included supplying and installing a 20 amp,
 110 v. ac "slow blow" circuit breaker in the residences as well as
 a suitable 20 amp, llOv. ac power line from the circuit breaker to
 the pump storate grinder unit.  The power cable was run underground.
 Figures 4, 5 and  6 show the PSG assembly as installed, the system
 layout (elevation) and the pipe and pump layout, respectively. The
 demonstration period extended for 6 months after system start-up.
 The data station was checked periodically by Phoenixville personnel.
 Data was collected by General Electric RESD personnel  on a weekly
 basis and reviewed to determine any system changes or trends which
 might indicate future problems.  The PSG units were also inspected
 on a weekly basis by General Electric RESD personnel.   Until system
 safety was assured, these inspections included a check for objection-
 able gas formation.  Inspection procedures are outlined in Appendix
 B.
                               -17-

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                                GROUND LEVEL
                                     SEWAGE FROM HOUSE
                                   CONCRETE BASE
                                   REINFORCED CONCRETE  PIPE
                                   INLET LINE
                                   PRESSURE LATERAL
                                   POWER LINE
                                   VERTED CONCRETE  COVER
                                   BALL VALVE
                                   3/4" TO 1-1/2" REDUCER
                                   COUPLING, GE SUPPLIED
                                   CHECK VALVE, GE  SUPPLIED
                                   PLUG, GE SUPPLIED
                                   CONTROL BOX, GE  SUPPLIED
                                   GROUT
                                   SUPPORT, GE SUPPLIED
                                   HANGER, GE SUPPLIED
                                   BRACKET, GE SUPPLIED
                                   ALARM SENSOR, GE SUPPLIED
                                   RELIEF VALVE, GE SUPPLIED
                                   LEVEL SENSOR, GE SUPPLIED
                                   OVERFLOW LINE
                                   PUMP GRINDER, GE SUPPLIED
                                   DATA CABLE
FIGURE 4.  PUMP STORAGE GRINDER INSTALLATION

                    -18-

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VO
I
                                                                                                 STOKA6S
                                                                                                  T/tMK.
                                                                                             SffT/C^
                                                                                             TAUK ^s=55v f .4-1
                                                AIRKELIEF
                                                 AT HIGH POINT
              120


              110
-47" ~3O" &t/KY —• — '
1 1 1 1 1 1
1 1 1 III !
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IOOO    I2OO    I40O    tGOO    I&OO   ZOOO    22OO    Z4OO

               PROFILE
                 peer
                                                                                                                        300O
                                                                                           MAMHOLS
                                  FIGURE 5.   PRESSURE SEWER SYSTEM, - PHOENIXVILLE

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NS
O
                     CLEAN OUT
                              -e-
           PSG
           # 5
                   HOME # 4
                                                                                           PSG #2     PSG # 1
                                                                                                                 HOME # 1
                                                                   PSG # 3
                                                             2751
                                                                                   HOME # 3
                                              HOME # 2
                                                                           STATION # 2
                                                                                      BALL
                                                                                      VALVES
                                                                                                                                     MONITOR
                                                                                                                                     HOUSE
MAN
HOLE
                                                                                                                            H	
                                                                                           -ROUTE 113
STATION
# 1         UNDER ROAD IN
            6" A.  C. PIPE
                                                                                                   296'
                                    PSG # 4
                                                       LEGEND


                                                      	 PVC  PIPING

                                                      	  HOME SEWER OUTLET
                                          HOME # 4A
                                                                FIGURE  6 .   PIPE AND  PUMP LAYOUT

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The energy or hydraulic grade diagram for the system is shown in
Figure 7.  This diagram was developed by assuming that minimum
system pressure would occur when only unit #4 was operating.  From
this "minimum" pressure line and the pump Characteristic curve, (Figure
3), the actual flow from each storage grinder was calculated.  A new
"maximum" pressure line was then established based on all units
operating simultaneously.  A final calculation, utilizing this "max-
imum" pressure line, verified that the system would operate between
the pressure limits shown in Figure 7.

Assuming that a maximum pressure of 60 psig can be developed by each
unit, an "available" pressure line was plotted.  Since the "available"
pressure line is in every case above the maximum operating pressure,
the design is shown to be practical.  The minimum system velocity is
1.2 feet per second (fps) and occurs when PSG  #4   is operating alone.
This is compatible with the desired minimum scouring velocity of 1.0
fps.  With units  #4 & #5 operating together the velocity would  be 2.2
A computer program was developed to further describe and analyze the
Phoenixville pressure sewer system installation.  The program
(Phoenix) is a deskside digital computer program which calculates
flows, velocities, friction head and pressures based on the provided
input data.   The input data required are the number of stations,
pipe diameter, pipe length, and static head between stations.  A
station is defined as the junction of the road main and the laterals
from the PSG units.  Input data also required are the pipe diameter,
pipe length and static head of the laterals.  This also requires
an initial pressure at Station 1 and the interface pressure with
the connecting system.  If the connecting system is a gravity sewer
the interface pressure will nominally be zero.

The Program takes the input pressure at Station 1 and calculates the
pump pressure and flow.

Summing pump flow at Station 1 the program calculates the friction
head in the road main to Station 2.  The program then calculates
the pressure at Station 2.  The process is repeated at each station
until the interface or discharge pressure is calculated.  If the
discharge pressure is greater than 0.05 psi the program calculates
a new input pressure and repeats the previous calculations.  Several
iterations are, generally required for a solution.
                               -21-

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NJ
NJ
I
                                    A\R RELIE1F  V/LVF
                                                                                             138 FT./boPS/G AVAIL.
                                                                                             FROM  PS©, MINUS  1.5"
                                                                                             LATERAL  PIPE  A/V£>
                                                                                             F/TT/NG  LO5S.
                                                                                             MAXIMUM  HYDRAULIC
                                                                                             GRADE:  UME, a
                                                                                             ALL  MAI ITS
                                                                                                       H y ORAUUC
                                                                                                   UNE-, 2" M/?//Y
                                                                                            UN/T*4 OPERATING
                           5OO
IQOO
                                                    1500
ZOOO
2500
                                                                                          300O
                                                                                              ROAD  PROFILE

                                                                                             (Pressure sewer -2.5
                                                                                                 	,	,    —£-Ja
                                   EEET   (ALONG   ROAD  )

                                              FIGURE 7 .  HYDRAULIC  GRADE DIAGRAM

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The equations used in the program are the  pressure-flow characteristics
of the pump and the friction head of the pipe.  The equation of the
progressive cavity pump characteristics is:

                            Qfo - 15.0 - 0.115 P0
Where:                      Q0 = Pump output flow, gpm
                            Po = Pump output pressure, psig

The head loss due to fluid flow in the pipe is calculated using
the empirical Hazen-Williams formula:
                                            1.852
Where:                       Hf = Friction head per foot, ft,

                             V  = Fluid velocity, ft./sec.

                             D  = Pipe diameter, ft.

                             C  = Coefficient representing roughness
                                  pipe interior surface (C=150 for
                                  PVC pipe).

The characteristics of the  equipment used at Pltoeftixville are listed
below:

1.   Pump Storage Grinder

     The PSG units were of the design configuration shown in Appendix
      A .  This particular design required that the uppermost part of
     the PSG, the electrical cable exit and potting, be above the
     overflow line.  This requirement  was necessary because the
     units were not completely submersible.  Units #'3  and 4  were
     piped to allow for the incorporation of a temperature sensor "and
     pressure transducer.  The control box was mounted on brackets
     attached to the storage tank.  Electrical power was supplied to
     the box from the home using #12-gage wire and connected with
     twist lock plugs, as shown in Figure 4.  The control features
     included an on/off switch and the necessary circuitry to operate
     the unit and level sensing system.  Since the overflow alarm
     sensor was for data only, it was not required to be routed
     through the control box.  Electrical power was llOv. ac, single
     phase, 60 Hz.
                               -23-

-------
1.   Pump Storage Grinder (Cont'd)

     The level sensing system used on the first pump storage
     grinders field tested by GE-RESD relied on a pressure
     differential switch that sensed the pressure buildup of
     an air column trapped in a dip tube.  This method of
     level control was plagued with two problems: one, air
     leakage in the dip tube, and two, dip tube blockage caused
     by wastewater solids.  The five pump, storage grinders tested
     at Phoenixville, used a submersible pressure differential switch
     for level control.  The switch consists of a snap action,
     double throw, micro switch that is activated by a rubber
     diaphragm.  At the time of the demonstration, the submersible
      differential switch was  available with only a  few  different
     operating pressure differential settings.  The switch
     selected has a differential of 7 inches between actuation, and
     cut-off level.  When installed in a 30-inch diameter tank,
     the level sensing system would actuate the PSG when approxi-
     mately 45 gallons of wastewater had accumulated and deactivate
     the unit after pumping approximately 20 gallons, leaving a
     residual of 25 gallons in the storage tank.

     The choice of operating range for the switch, is somewhat
     arbritary, although dependent on other system parameters
     such as anticipated wastewater influx, tank size, operating
     cycles or system programming and pump capacity.

2.   Piping

     Polyvinylchloride (PVC) pipe was used at Phoenixville because
     of its availability.   The PVC was schedule SDR-26; it was
     capable of withstanding hydrostatic working pressures of
     160 psig at 73°F, and conformed to requirements set forth
     by ASTM-D 2241.  All 2-inch pipe had an inside diameter of
     2.2 inches.  All 1% inch pipe had an inside diameter of 1.75
     inches.  All fittings were PVC schedule 40.  All pipe was
     installed at a depth of 30 inches.  The trench did not exceed
     4 inches in width except where necessitated by rock removal.
     Loose bed rock was removed by a backhoe.  All of the PVC
     pipe was encased in 4 inch asbestos cement pipe where it
     crossed under public or private roads.  The PVC pipe was
     handled and installed in strict accordance with the manu-
     facturer's instructions.  Care was taken during installation
     to prevent entry of foreign material which would have
     hindered flow through the pipe.  The pressure system was leak-
     checked at a pressure of 100 psig at the completion of construc-
     tion.  As shown in Figure 7, the maximum system operating
     pressure analytically should have been below 60 psig.
                               -24-

-------
2.   Piping (Cont'd)

     Access to the pipe lines was available through fittings at
     each pump storage grinder unit and through the clean-out
     box at the "bottom" of the system, illustrated on the right
     hand side of Figure 6.

3.   PSG Storage Tank

     The storage tanks were constructed from 8-foot sections of
     30-inch inside diameter reinforced concrete sewer pipe.  The
     pipe met the requirements set forth by ASTM and the Pennsylvania
     Department of Transportation for C76, Class 3 pipe.  The 8-foot
     section of pipe was installed so that the top was level with the
     ground.  The base of the tank was a minimum of 6 inches of
     poured concrete.  A light duty cover was supplied by the con-
     struction contractor and was capable of withstanding the load
     of a home garden tractor or equivalent.  The cover was 36 inches
     in diameter.  The tank intercepted the existing home sewer
     line prior to its entry into the septic tank.  The overflow
     line was a minimum of 36 inches from the bottom of the tank.
     The inlet line was higher than the overflow point.  The actual
     tank depth was determined by the above requirements, as well
     as the depth of the existing home sewer line.

4.   Data System

     The data system supplied operating and chemical data.  Electrical
     power (110 v. ac, single phase, 60 Hz) was available in the data
     station to operate the data system.  A small electric heater
     was also used.  The data system operated for the total 6-month
     demonstration period.  All sensors were installed so that they
     were readily accessible for maintenance purposes, and the
     system contained calibration capabilities.  The data station
     was approximately 8' x 10' x 61 high, was locked, and was
     sturdy enough to prevent vandalism.  Data was transmitted from
     the individual sensors to the data station via the data cable.

     The operating data included on time, overflow time and real
     time for each unit, and temperature and pressure readings at
     units  #  3,  #  4 and the data station, as shown in Table 1.
     The operating real times were determined from the recorder
     chart speed.  Temperature was monitored with a thermistor probe
     attached to the outside of a section of pipe.  This section
     of pipe was over-wrapped with insulation.  The probe was located
     a minimum of 3 inches from either end of the insulation.
                              -25-

-------
                                            TABLE 1

                                     PERFORMANCE DATA LIST
MEASUREMENT

On and overflow time




Total cycles

Operating pressure


Temperature
FREQUENCY
1/48 sec.

as occur
1/44 sec
LOCATIONS
PSG #'s

PSG #«s
PSG #' s
1-5

1-5
3 & 4
TYPE OF SENSOR
Relay contacts
level switch
contacts
Counter
Transducer
1/44 sec
Data Station

PSG #• s.  3 & 4
Data Station
Thermistor

-------
4.   Data System (Cont'd)

     The pressure transducer was used in conjunction with a small
     diameter, silicone grease filled, interface tube between the
     transducer and the wastewater.  All sensors which were installed
     in the storage tanks were capable of operating in high humidity
     environments at outdoor ambient temperatures.  The recorder was
     the multiple (24) point type and was capable of running one week
     without the need to refill the chart paper.  The monitor panel
     contained lights to indicate an "on" or an "overflow" condition
     for each unit.  The data cable was a standard type used by
     utility companies for underground installation.

     The wastewater characterization data was obtained from waste-
     water grab samples which were collected and analysed during
     3 sample periods.  The wastewater samples where obtained via
     a hand valve in the main pressure line in the data station.
     Composites were prepared by taking several grab samples over a
     period of time until a liter of solution was obtained.  Each
     grab sample was approximately 200-300 ml.  The following
     analyses were performed:
                             Alkalinity
                             Ammonia Nitrogen
                             Bacterial Count (Coliform)
                             Biochemical Oxygen Demand (BOD)
                             Calcium
                             Chemical Oxygen Demand
                             Chloride
                             Conductivity
                             Detergents
                             Dissolved Oxygen
                             Magnes ium
                             Nitrate
                             Oxidation-Reduction Potential (ORP)
                             pH
                             Phosphate
                             Settleable Solids
                             Sulfate
                             Total Suspended Solids (TSS)

     The oxidation reduction potential (ORP) was to be obtained by
     continuously recording the output of an ORP sensor located in
     the data station.  However, an unprecedented long strike against
     the vendor (Leeds & Northrup) precluded us from obtaining this
     data continuously.  Instead, the oxidation-reduction potential
                               -27-

-------
4.   Data System (Cont'd)

     of the grab samples was measured using a portable,
     battery-powered ORP meter.  The magnesium and'calcium
     analyses were performed by the atomic absorption method.
     All other analyses were performed according to Standard
     Methods for Examination of Water and Wastewater, 13th
     Edition.

5.   System Costs

     Table 2 lists the material and installation costs of household
     related equipment, such as the PSG and its storage tank, used
     in the Phoenixville pressure sewer system.  The PSG unit cost
     of $900.00 was based on prototype models.  The total costs
     listed for item 2 through 6 were actual costs charged to the
     project by the contractor.  The cost per unit, per foot or per
     installation was calculated by dividing the total cost by the
     actual quantity of material used in the system.

     Table 3 lists material and installation costs related to the
     Phoenixville pressure sewer main.  The total cost listed for
     the various items were costs charged to the project by the
     contractor.  Once again, as in Table 2, the unit cost was
     calculated by dividing the total cost by the actual quantity
     in the system.

     Table 4 lists the costs related to the data collection.  It
     should be noted that a typical pressure sewer system would
     not require a data collection system.

     It is difficult to provide meaningful cost estimates for
     future installations because they depend on such factors as
     the number of homes, total distance and piping runs, soil
     of conditions, type of equipment available,  pipe sizes, new
     construction or converting present installations,
     whether or not any existing facilities are available.
                               .28-

-------
                             TABLE 2

   COST OF HOUSEHOLD RELATED EQUIPMENT FOR THE PHOENIXVILLE PROGRAM
ITEM
PUMP STORAGE GRINDER (PSG)
AND CONTROLLER
UNIT COST
 $/UNIT
  900.00 per
  UNIT
STORAGE TANK; EXCAVATE,
SUPPLY AND INSTALL 30" DIA.
8f LONG SEWER PIPE SECTION;
POUR CONCRETE BOTTOM, SUPPLY
COVER; TIE-IN HOME SEWER IN-
PUT LINE, OVERFLOW LINE,
PRESSURE.LATERAL; INSTALL
PSG AND RESTORE AREA.

PRESSURE LATERALS; SUPPLY
1%" PVC PIPE - SCHEDULE
SDR-26, EXCAVATE, INSTALL
AND RESTORE AREA.

HOME CIRCUIT BREAKER;
SUPPLY AND INSTALL

POWER CABLE; SUPPLY AND
INSTALL SUITABLE UNDER-
GROUND ELECTRICAL CABLE
FROM HOME CIRCUIT BREAKER
TO PSG STORAGE TANK.

MISCELLANEOUS PVC PIPE
FITTINGS USED IN PRESSURE
LATERAL TIE-IN TO PSG.
  600.00 per
  INSTALLATION
  2.50 per
  LINEAR FOOT
  60.00 per
  INSTALLATION
  3.00 per
  LINEAR FOOT

  20.00 per
  INSTALLATION
QUANTITY



 5 units

 1 spare
                TOTAL
                COST
               5,400.00
5              3,000.00
INSTALLATIONS
700 FEET
TOTAL
INSTALLATIONS
                1,750.00
                 300.00
200 FEET
TOTAL
INSTALLATIONS
                  600.00
                  100.00
                  (APPROX)
                                                TOTAL        $11,150.00

AVERAGE COST PER RESIDENCE, EXCLUDING COST OF SPARE UNIT     $ 2,050.00

AVERAGE COST PER DWELLING UNIT  (12)  (LESS SPARE)             $   854.17
                               -29-

-------
                              TABLE  3

          COSTS RELATED TO  PHOENIXVILLE PRESSURE SEWER MAIN
 ITEM
 PRESSURE MAIN;  SUPPLY 2"
 PVC SCHEDULE SDR-26  PIPE,
 EXCAVATE, INSTALL, TIE-IN
 TO PRESSURE LATERALS AND
 RESTORE AREA.

 ROCK REMOVAL  ON A  PER
 CUBIC YARD BASIS

 RESTORATION OF  PAVED HIGH-
 WAYS AND DRIVES ON A PER
 CUBIC YARD BASIS.

 RESTORATION OR  UNPAVED
 DRIVES  ON A PER CUBIC
 YARD BASIS.
UNIT COST
 $/UNIT
QUANTITY
   2.00 per
  LINEAR FOOT

  20.00 per
  CUBIC YARD

  15.00 per
  CUBIC YARD
  2.00 per
  CUBIC YARD
 PROTECT ALL PRESSURE SEWER
 PIPE WHICH RUNS  UNDER HIGH-
 WAYS OR DRIVES BY ENCASING
 IT IN ASBESTOS CEMENT PIPE,
 4-INCH DIAMETER; ON A PER    3.00  per
 LINEAR FOOT BASIS.           LINEAR FOOT
 AIR RELIEF  VALVE:   SUPPLY
 AND INSTALL IN PRESSURE
 MAIN;  PROTECT IN BUFFALO
 BOX (6"), RISERS (30"
 HIGH X 4" DIAMETER)

 PROVIDE CLEANOUT;  SUPPLY
 SHUT-OFF VALVE,  PROTECT  IN
 BUFFALO BOX (6"),  RISERS
 (30" HIGH X 4"  DIAMETER)
  350.00 per
  VALVE
  350.00 per
  INSTALLATION
 TOTAL
 COST
 _$	
 2800 FEET
 60 CUBIC
 YARDS

 10 CUBIC
 YARDS
 50 CUBIC
 YARDS
5,600.00


1,200.00


  150.00



  100.00
                     40 FEET
 1 REQUIRED
                  120.00
  350.00
 1 REQUIRED
                                               TOTAL

AVERAGE COST PER FOOT OF PHOENIXVILLE SEWER MAIN     $2.82
  350.00
                                   $7,870.00
                               -30-

-------
                              TABLE 4

                  COSTS RELATED TO DATA COLLECTION


                                                             TOTAL
ITEM                                          QUANTITY       COST
                                                            _J	

DATA STATION STRUCTURE                         1            1,100.00

DATA CABLE - 52 PAIR: ON A PER LINEAR
FOOT BASIS :  SUPPLY AND TIE-IN.                3000 FEET    5,500.00

DATA CABLE - 13 PAIR; ON A PER LINEAR
FOOT BASIS, SUPPLY AND TIE-IN.                  500 FEET      500.00

CONNECT PRESSURE SEWER SYSTEM TO DATA          1              820.00
STATION:  SUPPLY AND INSTALL VALVES,
PROTECT IN BUFFALO BOXES (6"), RISERS
(30" HIGH X 4" DIAMETER)

INSTRUMENTATION (MISC)                         -            1,400.00


         TOTAL COST OF PHOENIXVILLE DATA COLLECTION SYSTEM $9,320.00
                               -31-

-------
                           SECTION VIII

                       DEMONSTRATION RESULTS


The following paragraphs present the data obtained from the demon-
stration, including operating cost.  Reference to Appendix B will
identify the typical check-off list used at the site for data
collection.

     1.   PSG Use Characteristics

          The total operating time and cycles for each unit as well
          as the type of residence serviced is given in Table 5.
          Table 6 shows the average operating time per cycle for
          each unit by month.  The average operating time per cycle
          is related to the operating differential of the level
          switch and to the pump output.  The operating time per
          cycle of units #1, #2, #3, and #5 was lower than that
          expected.   Investigation revealed that the level switch
          used on these units had a 4-inch differential instead
          of the 7-inch differential.  Unit #4 did have a 7-inch
          differential level switch.  Table 7 shows the average
          PSG operating time per day by month.  Typical weekly
          use profiles were plotted for each unit and the system
          in Figures 8 (a) through 8 (f).  Unit operating time
          in minutes per real time hour was plotted for a week.
          The intent of these profiles was to identify peak
          activity periods during the day and week.  The use
          profile data was obtained by reducing the output of a con-
          tinuous strip chart recorder, operating at a speed of 8
          inches per hour, that was recording unit operating time.
          The use profile shown are representative of the beginning,
          middle and end of the demonstration period.

     2.   Flow and Pressure Data

          The flow and pressure characteristics of the system were
          initially described by the computer program.  The computer
          program calculated pressure and flow characteristics at each
          of the five PSG locations and three station locations.   The
          results of several computer runs are shown in Table 8.   It
          can be seen from the data that PSG's #1, #2, and #3, which
          are at the higher elevation, operate at relatively low pres-
          sures, i.e., less that 12 psig.  Units #4 and #5 which are
          at the lower elevation operate at roughly 35 psig when
          operating alone.  The discharge pressure of each pump rises
                               -33-

-------
-p*
                                                       TABLE 5




                                              PSG  USE CHARACTERISTICS
PUMP STORAGE
GRINDER NO.
#1
n
#3
#4
#5
TOTAL
HOURS
50.9
160.0
102.8
182.4
123.4
TOTAL
CYCLES
4526
15306
6792
5016
6946
TOTAL DAYS
IN SERVICE
195
195
190
189
189
TYPE OF RESIDENCE 'SERVICED BY PSG
SINGLE HOME
5 APARTMENT UNITS (2 houses)
SINGLE HOME
4 APARTMENT UNITS + SINGLE HOME
3 APARTMENT UNITS
NO.
PEOPLE
2
11
3
10
6

-------
                             TABLE  6




                   PSG  OPERATING TIME  PER CYCLE*






                        PUMP STORAGE GRINDER
MONTH
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
AUGUST
#1
0.66
0.66
0.66
0.69
0.67
0.71
0.67
#2
0.70
0.58
0.57
0.55
0.68
0.66
0.73
#3
0.87
0.87
1.0
0.91
0.92
0;96
0.93
#4
2.11
2.02
2.03
1.83
2.29
1.97
«• «•«••
#5
1.05
1.22
1.05
1.09
1.06
1.04
0.91
*A11  values are expressed in minutes/cycle
                               -35-

-------
                              TABLE 7




                PSG AVERAGE OPERATING TIME PER DAY*
MONTH
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
ATTHTTST
#1
26.8
23.8
15.3
11.1
12.3
8.15
14..9
#2
91.5
67.5
50.6
39.4
39.0
23.2
A^.fi
#3
64.5
38.0
26.9
39.8
26.1
4.2
LQ S
#4
34.0
38.6
59.5
79.3
74.6
68.2

#5
19.0
39.3
24.5
33.2
36.5
51 = 4
<^ LL
*A11 values expressed in minutes/day
                               -36-

-------
co
^i
 i
                                                                                                                 SA
                                                                                                                                    Jtl   TTO17  T>T>(-ITJTT T?

-------
I
co
oo
                                                  FIGURE 8B.  PSG #2 USE PROFILE

-------
I
CO
                                                   FIGURE 8C-   PSG #3bUSE PROFILE

-------
FIGURE 8D .  PSG #4 USE PROFILE

-------
FIGURE 8E.  PSG #5 USE PROFILE

-------
•p-
N5
                                                    FIGURE 8F.   USE PROFILE

-------
         TABLE 8




COMPUTER ANALYSIS OF SYSTEM
PSG UNITS PUMP
OPERATING NUMBER
1 1
2 2
3 3
4 4
5 5
1 & 2 1
2
4 fit 5 4
5
All units 1
2
3
4
5
PUMPS PUMP STATION STATION
PRESSURE 'FLOW NUMBER PRESSURE
psig gpm # psig
10.3
10.6
11.7
34.9
35.1
23.4
23.6
43.7
43.9
20.3
20.5
23.1
52.3
52.5
13.8
13.8
13.7
11.1
11.1
12.4
12.4
10.1
10.1
12.7
12.7
12.4
9.1
9.1
3
3
2
1
1
3
3
1
1
3
3
2
1
1
3.5
3.4
6.0
31.0
31.0
19.1
19.1
40.4
40.4
14.5
14.5
18.4
49.7
49.7
STATION
FLOW
gpm
13.8
13.8
13.7
11.1
11.1
24.7
24.7
20.2
20.2
56.1
56.1
30.7
18.3
18.3
FRICTION
HEAD
feet
2.1
2.0
2.9
10.7
10.6
10.7
10.7
32.4
32.4
27.5
27.5
4.1
21.9
21.9
VELOCITY PIPE
DIAMETER
ft/ sec CINCHES
1.5
1.5
1.5
1.2
1.2
4.5
4.5
2.2
2.2
6.1
6.1
3.3
2.0
2.0
1.94
1.94
1.94
1.94
1.94
1.50
1.50
1.94
1.94
1.94
1.94
1.94
1.94
1.94

-------
2.   Flow and Pressure Data (Cont'd)

     substantially when all units are running simultaneously,
     as illustrated by the data in Table 8.

     The maximum pressure calculated by the computer is 52.5
     psig which is the discharge pressure of PSG #5 when all
     units are operating.  The maximum flow in the system,
     56.1 gpm, is found at station #3 when all units are
     operating.  The minimum flow in the system is 9.1 gpm.
     This flow represents the discharge flow rate of units
     4 and 5 when all other units are operating as well. It
     should be noted that in all cases the fluid velocity is
     larger than the necessary 1.0 ft /sec  scouring velocity.
     It should be noted that the measured discharge pressures
     of units #3 and #4, at the beginning of the demonstration
     were very close to that calculated by the computer program.
     This would indicate that the program described the Phoenix-
     ville system quite well.

     As part of the data collection, pressure was monitored
     throughout the entire project at the data collection
     station, PSG #3 and PSG #4.  Pressure transducers were
     installed in the exit piping of PSG #3 and PSG #4 and
     in the two-inch PVC piping which ran through the data
     collection station.  The discharge pressure profiles of
     units #3 and #4, when they are operating alone, are shown
     in Figures 9 and 10.  The slight reduction of discharge
     pressure shown in Figure 9 could be the result of a worn
     pump stator or possibly a calibration drift of the
     pressure transducers used.  The increase in discharge
     pressure of PSG #4 shown in Figure 10 is too large to
     be caused by calibration drift.  This trend could possibly
     be an indicator of a gradual reduction of cross-sectional
     flow area.  At this time, however, a conclusive statement
     cannot be made.  The piping system was provided with a  clean-
     out if flushing became necessary.

     It was not possible to correlate wastewater efflux with water
     inlet to each home because the borough does not individ-
     ually meter water consumption.

-------
FIGURE 9. DISCHARGE PRESSURE-PROFILE  OF PSG  #3

-------
FIGURE 10. DISCHARGE PRESSURE PROFILE OF PSG #4

-------
3.   Wastewater Temperature Data

     The temperature of the wastewater in the pressure sewer
     system was monitored at the data collection station, PSG
     #3 and PSG #4.  In all three locations a thermistor probe
     was used.  The temperature sensors were calibrated at GE-
     RESD and also at the test site to insure an accurate
     calibration.  In the data collection station a temperature
     sensor was taped to the 2-inch PVC pipe with a special
     temperature insulating tape.  At units #3 and #4 the temp-
     erature sensors were located on the brass pipe fitting
     nearest the PSG exiti, The temperature insulating tape
     was used for attachment purposes as well as for insulation.
     Figures 11, 12 and 13 show the temperature profiles during
     the six^month demonstration period for these three locations.

4.   Wastewater Characterization
     The wastewater flowing through the pressure sewer was
     characterized by testing various grab samples taken
     from the sample port in the data collection station.
     The results of these tests are shown in Table 9.  In the
     interpretation of this data it should be emphasized that
     sappling was limited both in number of samples and time
     of day when taken.  Also, the wastewater is domestic
     waste and contains no industrial materials or significant
     storm water run-off as does municipal wastewater*  Some
     surface water did enter the tanks because they were set
     level with the ground and the covers were not water tight.

     The data presented shows the system to be operating in an
     anaerobic -(septic) mode.  This condition probably resulted
     from an excessive holding time, that is, the time elapsed
     from the moment the wastewater was introduced to the pressure
     sewer system to the time it was discharged into the gravity
     sewer line.  There were no gases or odors noticed around
     the PSG installations.

5.   Unit Operating Cost

     The unit operating cost per day, month, and year is
     given in Table 10.  The typical rate for the area, $0.03
     per kilowatt-hour was used in the calculations.  Units
     #1, #2, and #3 had an average current draw of 12.5 amps.
     Units #4 and #5 which operate at a high discharge pressure
     had an average current draw of 14.0 amps.
                      -47-

-------
-p-
00
                              FIGURE  11.   TEMPERATURE PROFILE OF FLUID FLOWING THROUGH DATA STATION

-------
FIGURE 12,  TEMPERATURE PROFILE OF PSG #3

-------
I

-------
I
Cn
                                                      TABLE 9



                                             WASTEWATER CHARACTERIZATION
DATE
PARAMETER SAMPLE TIME
pH
DISSOLVED OXYGEN (mg/1)
ORP (mv)



BOD (mg/1)
COD (mg/1)
SUSPENDED SOLIDS (mg/1)
SETTLEABLE SOLIDS (mg/1)
COLIFORMS (No/ 100 ml)
MAGNESIUM (mg/1)
CONDUCTIVITY (mhos /cm)
DETERGENTS (MB AS)
6/8/71
12:00 noon
1:00 p.m.
7.2
-
-



104
311
108
20
2.4X104
6.3
500
2
6/17/71
9:00 a.m.
11:00 a.m.
8.3
0
_



198
524
224
102
1.7X104
6.6
850
4.5
6/28/71 6/29/71
12:00 noon 9:00 a.m.
9:15 a.m.
8.3
0 0
-200 -230 9:00
-160 9:15


-
_
514
-
-
-
-
_
7/2/71 7/6/71
9:30 a.m. 9:30 a.
10:00 a.
7.9
0 0
-80 +60 9:
+30 9:
-10 9:
-20 10:
135
343
146
80
4.3X104
110
920
2.9
m.
m.


30
40
50
00









-------
                                        TABLE 9  (Cont.)


DATE                      6/8/71       6/17/71     6/28/71      6/29/71     7/2/71     7/6/71
PARAMETER SAMPLE TIME     12:00 noon   9:00 a.m.    12:00 noon   9:00 a.m.   9:30 a.m.  9:30 a.m.
                           1:00 p.m.  11:00 a.m.                9:15 a.m.	10:00 a.m.





1
Ul
NJ
1




AMMONIA NITROGEN (mg/1)
as NH3-N
TOTAL PHOSPHATE (mg/1)
as PO4~P
ALKALINITY (mg/1)
as Ca03

SULFATE (mg/1)
NITRATE (mg/1)
as N03-N
CHLpRIDE ftng/l)
CALCIUM (mg/1)
36.3

5.8

188


72
2

42
37
66.5

19 -

315


78
2

68
28
74.1

9.6

360


100
2

.-92
20.6

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l/l
                                                      TABLE 10




                                         UNIT AVERAGE OPERATING TIME AND COSTS
PSG
1 -
2 -
3 -
4 -
5 -
NO.
SINGLE HOME
2 PERSONS
2 HOMES (5 APART,'
11 PERSONS
SINGLE HOME
3 PERSONS
4 APART. + 1 HOME
10 PERSONS
3 APARTMENTS
HRS/DAY
.27
>
.87
.55
.98
.57
$/DAY
.012
.039
.025
.05
.03
HRS/MO.
8.1
26.0
16.5
29.4
17.1
$/MO.
.36
1.20
.75
1.60
.90
HRS/YR.
98
318
200
358
208
$/YR.
4.40
14.30
9.10
19.00
11.00
               6 PERSONS
           TOTAL
3.24
.16
97.1
4.81
1182
57.80

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6.   Problems Encountered

     During the check-out phase of the project, the holding
     tank for PSG #5 was filled with water when a valve
     coupling was inadvertently removed allowing the system
     to drain into the tank.  Also during this phase, unit #3
     was found to have a large chunk of concrete firmly
     wedged in the inlet hopper (throat).  It is unclear
     how this occurred.  The concrete could not have been
     sucked in since it was too heavy and too tightly wedged
     into the hopper.  As a result of this, the two cutter blade
     retaining screws were sheared.  These were replaced and
     the unit was returned to service.

     On March 9, 1971, the control box in tank #3 was replaced
     with the spare control because of unpredictable circuit
     breaker operation.  Investigations at GE-RESD found no
     problem with the rest of the control box equipment which
     performed properly with a new circuit breaker.

     On April 1, 1971, the pump grinder in tank #4 became
     inoperative and was replaced with the spare pump grinder.
     The inoperative unit was rfound to be filled with water
     which caused the motor to electrically short.  The water
     had entered the unit through a fracture in the stainless
     steel flexible outlet line.  The fracture was in the
     line near the pump fitting end and was attributed to a
     defective part.

     Some slight difficulty was experienced with the data
     station and air relief valve pipe.  On March 9, 1971,
     it was determined that the power line to'the'data station
     and the air relief valve pipe needed repairs.  The
     power line voltage was low and the relief valve pipe
     had been damaged, probably during routine snow removal
     by heavy equipment.  The complete pressure sewer system
     was shut down during March 9 and 10 while repairs were
     quickly completed.  Later, on April 12, 1971, the
     recorder print out drive line was found broken.  The line
     was repaired, and the recorder was back in operation
     on April 16.  This problem was found again on May 18,
     1971 and repairs were completed on May 19.
                      -54-

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6.   Problems Encountered  (Cont'd)

     On July 29, the pump grinder in tank #4 became inoperative,
     The unit was brought back to GE-RESD for analysis.  The
     failure analysis showed that the flywheel cutter assembly
     had backed off of the motor shaft slightly,  thus  reducing
     the necessary compression on the rotary shaft seal.
     Water had entered the unit via the shaft seal and elec-
     trically-shorted the motor.  The unit was repaired and
     placed back into  operation August 26.

     On Oct. 21, 1971, -during the final  routine check  of the
     system,  units  #3,  #4, and #5 were found inoperative.
     Investigation revealed that there was no power at units
     #4 and *5 due to faulty cable splices installed by the
     contractor.  Unit #3 had a ruptured flexible line.
     This deficiency had been previously experienced, and
     corrective action was instituted by changing to a
     rubber hose.  All three units were updated by incor-
     porating  the flywheel lockwire, and replacing the
     steel flexible hose with rubber hose.
                       -55-

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                           SECTION IX

                         ACKNOWLEDGEMENTS
Mr. John Kane, former manager of  the  Borough of Phoenixville,
Pennsylvania, played a vital role in  getting the project
approved and underway.  His support of the project and assistance
during the construction phase and system  start up is acknowledged
with sincere thanks.  The  support of  Mr.  Stephen Ross, acting
manager of the Borough of  Phoenixville, Pennsylvania, during the
demonstration period is acknowledged  with sincere thanks.

The Re-Entry and Environmental Systems Division of the General
Electric Company (RESD), Philadelphia, Pennsylavania, is credited
with the design of the Phoenixville Pressure Sewer System and the
implementation thereof, including the design and manufacture of the
Pump Storage Grinder units and the design of the data monitoring
system.

The engineering effort was conducted  under the-management of Mr.
Gilbert E. DiSalle, manager of Actuation  Equipment Engineering,
RESD, and Mr. James F. Hall, Jr.  former manager of Machine Design
Engineering, RESD., and Mr. Daniel 0. Ramos, Project Engineer,
RESD.

Mr. George Mekosh, Jr., design engineer,  RESD, was responsible
for providing engineering  support during  system installation,
monitoring the demonstration and  writing  this report.

The installation of the pressure  sewer system was performed by the
Altemose Construction Company, Norristown, Pennsylvania, under the
direct supervision of Mr.  Lester  Horvath.

The support of the project by the Environmental Pfote&tion Agency
and the help provided by Mr. James F. Kreissl, Project Officer,
is acknowledged with sincere thanks.
                              -57-

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                            SECTION X


                           APPENDICES

                                                             PAGE

A.     P.S.G. OPERATION AND INSTALLATION MANUAL               61

       FIGURE A-l PSG INSTALLATION                            66

B.     CHECK-OFF LIST PROCEDURE FOR PHOENIXVILLE              69
       PRESSURE SEWER INSPECTION
                               -59-

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       APPENDIX A
    PUMP STORAGE GRINDER
OPERATION AND INSTALLATION
          MANUAL
           -61-

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OPERATION
    The basic function of the Pump Grinder is to mascerate and then
    transport wastewater,under pressure.   The primary control element
    of the Pump Grinder, as shown in Figure A-l, is a simple, rugged
    diaphragm switch.  When the water level in the storage tank rises
    to a preset level, the diaphram switch closes and activates a
    set of relays.  These relays which are located inside the
    control box start the motor which drives the pump and the grinder.
    During operation, water and solids pass through the grinder and
    the solids are reduced in size to less than 1/4 inch.  After
    the mascerated wastewater leaves the  grinder it enters the pump
    inlet line, passes through the pump,  through a check valve, and
    into the discharge pipe.  The check valve prevents back-flow.
    As the water level in the storage tank drops to a given level,
    the diaphragm switch opens and shuts  off the motor.   The pump
    grinder is also equipped with an overflow alert switch.   This
    switch will send out a signal when the system is in an over-
    flow condition.
                             -62-

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                 PUMP GRINDER SPECIFICATION SHEET


1.    Funct ion;

           Shred and pump wastewater through small diameter plastic
           pipes.  Store peak loads until processed.

2.    Grinder Performance;

           Materials are ground to less than 1/4 inch in size before
           entering the small diameter piping.  Heavy materials,
           such as metals, settle to the bottom of the tank for
           periodic removal.  All materials can be handled (paper,
           wood, cloth, plastic, rubber, etc.).

3.    Pump Performance;

           8 gpm @ 60  psig

           15 gpm @  0  psig

4.    Motor;

           1 Hp, 1725  rpm, capacitor start, thermally protected,
           115V. ac, single  phase.

5.    Dimensions;

           Unit  diameter  : 11"

           Unit  Height   : 32"

           Tank diameter  ; 30"

           Tank height   ; as  required

6.    Net Weight;   (not including  tank)

            280 pounds

7.    Safety;

           The electrical system is  protected by a circuit breaker.
           The motor is also thermally protected.   The  system has  a
            check valve which prevents  wastewater from flowing back
            into the unit  when it is  not operating.  The>pump itself,
           when not operating, serves  as a check valve.  The pump  and
           discharge lines are protected by.a relief valve.   The re-
            lief valve is  set to open at 70 to 75 psig.   The  tank is
                                -63-

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7.    Safety;  (Cont'd)

           equipped with an overflow pipe.

8.    Material;

           Materials in contact with sewage:  Brass;  Black Iron;
           300 and 400 series Stainless  Steel;  Neoprene Rubber;
           Concrete.
                              -64-

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             PUMP GRINDER INSTALLATION  (See Figure A-l)


     The two support channels are attached to the pump grinder first.
The channels initially are only hand tightened since a final adjust-
ment will be needed.  Note the channels should be 12 inches above
the pump grinder.  The check valve-relief valve assembly is attached
next.  Be sure to use a pipe joint compound on all threaded joints.

     Next, install the diaphragm switch assembly.  The on/off level
switch and the overflow alert switch are suspended from a common
threaded rod which is attached to one of the support channels.  The
on/off switch is located at the same level as the pump grinder inlet,
two inches off the botton of the tank.  The overflow alert switch
is located 14 inches below the overflow line.

     The tank brackets are installed next.  The tank brackets
serve as mounts for the two support channels.  They are located
46 inches from the tank bottom.  The pump grinder is lowered into
the tank and secured to the tank brackets.  To produce the two
inch clearance  necessary, adjust the pump grinder depth by means
of the four threaded rods.  The two inch clearance is necessary
to insure proper scouring of the tank bottom.

     The discharge piping is connected next using as few bends
and elbows as possible.

                    CONTROL BOX INSTALLATION

     The control box is supported by two angles which are attached
to the tank wall.  The angles are located so that the control box
can be attached to the angle by the rear hole of each control
box flange.  The control box is mounted far enough from the wall
to permit the opening of its door.

                      ELECTRICAL CONNECTIONS

     The pump grinder is equipped with two electrical cables which
must be connected to the control box.  The three conductor cable
P4 coming from the motor carries motor current and is connected to
P3 of the control box.  The two conductor cable P6 coming from the
motor goes to its capacitor which is located in the control box.
P6 is connected to P5 of the control box.
                              -65-

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                                       INLET LIKE
                                       OVERFLOW LINE
                                       PRESSURE LATERAL
                                       POWER LINE
                                       PUMP GRINDER
                                       CONTROL BOX
                                       VENTED CONCRETE COVER
                                       CONCRETE SEWER PIPE
                                       CONCRETE BASE
                                       SUPPORT CHANNEL
                                       TANK BRACKET
                                       SUPPORT ROD
                                       RELIEF VALVE
                                       CHECK VALVE
                                       UNION
                                       PVC BALL VALVE
                                       LEVEL SWITCH
                                       OVERFLOW SENSOR
FIGURE  A-l •   PSG INSTALLATION
       -66-

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     The on/off switch Pi is connected to Jl of the control box.
Be sure the vent tube in the cable is pointing downward to prevent
debris from entering.  The power line from the house is labeled
P8 and is connected to P7 of the control box.

     The control box has a two conductor cable J2 which is connected
to P2 of the data cable.  This cable carries a signal indicating
operating time.  The overflow alert switch is also connected to the
data cable.  Be sure to have the vent tube in the switch cable
pointing downward to prevent debris from getting into the vent tube.
                               -67-

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                        SYSTEM START - UP
     The Pump Grinder may require priming prior to the initial
start-up.  This is accomplished by manually opening the relief
valve.  Be sure there is enough water in the storage tank to
warrant a start-up, approximately 16 inches.  Turn the pump
grinder on, operating it in the manual mode.  This is accomplished
by first opening the control box door.  Then actuate the circuit
breaker to the "ON" position.  Next actuate the toggle switch to
the manual position.  The toggle switch is labeled "M" for manual
operation and "A" for automatic operation.  When water starts to
come out of the relief valve exit, change the mode of operation to
automatic and immediately close the relief valve.  The pump grinder
should begin pumping water through the discharge line.  Let the
pump grinder pump down and shut off automatically.  Check to see
that the residual water is 7 to 9 inches deep.  If the water level
is more than 9 inches deep lower the on/off switch by means of the
threaded rod attached to the support channel.  Next, let water
enter the storage tank and note the level at which the pump
grinder starts automatically.  This level should be 14 to 16 inches
high.  Be sure that the overflow alert switch is 14 inches below the
bottom of the overflow pipe.  The control box door is closed and
secured by the two clamps before completing the installation.
                             -68-

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                            APPENDIX B

                     CHECK-OFF LIST PROCEDURE

                               FOR

              PHOENIXVILLE PRESSURE SEWER INSPECTION



1.   Record cycles and operating time for each unit on the  data
     form provided.

2.   Note overflow condition relative to alert lights.

3.   Change Recorder paper and label used roll as to time and
     date removed also number of cycles and total operating minutes
     of each unit.

4.   Install recorder paper and label new roll as to time started and
     date, number of cycles and total operating minutes of  each unit.

5.   Make gas level check on each installation.

6.   Note general condition of each data station.

     a)  Possible piping leaks

     b)  Unusual operation of instruments

7.   Make visual inspection of each unit (2 men required).

     a)  Note possible overflow

     b)  Excessive corrosion

     c)  Sludge build up in the tank

     d)  General condition of installation
                              -69-

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                            DATA FORM

                               FOR

              PHOENIXVILLE PRESSURE SEWER INSPECTION
CONDUCTED BY:
ACCOMPANIED BYs
DATE:
                     TIME:
LOCATION
OVERFLOW
ALERT
(ON/OFF)
CYCLES
                                  (NUMBERS)
TOTAL
OPERATING
(MINUTES)
COMMENTS
     NOTE:
                  IF  ANY OF THE OVERFLOW ALERT LIGHTS ARE ON, NOTE  IN
                  THE COLUMN LABELED OVERFLOW LOCATED ON THE DATA FORM.
                  THEN PRESS THE  RESET  BUTTON.   IF ANY OF THE LIGHTS
                  STILL REMAIN ON, AN OVERFLOW CONDITION EXISTS.
                  VERIFY OVERFLOW BY VISUAL  INSPECTION.  THEN CALL,
                  AS  SOON AS POSSIBLE,  GENERAL ELECTRIC, PHILADELPHIA

                  COMMENT ON ANYTHING WHICH  APPEARS UNUSUAL:  VIBRATION,
                  EXCESSIVE SLUDGE BUILDUP,  SCALING, CORROSION, CON-
                  DENSATION, ETC.
                              -70-

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 SELECTED WATER
 RESOURCES ABSTRACTS
 INPUT TRANSACTION FORM
                                                       No.
                                                                   3. Accession No.
                                                                   w
  4. Title   PRESSURE SEWER DEMONSTRATION AT
         THE BOROUGH OF PHOENIXVILLE, PENNSYLVANIA
7. Awthorfe.   Mekosh, G.,  and Ramos, D.

 T.  organization:
                      Philadelphia, Pennsylvania
                    Re-Entry and Environmental System Division


 12.
 15. Supplementary Notes
         Environmental Protection Agency report number,
         EPA-R2-73-270, July 1973.
                                                                     10. Project No,
                                                                      11050 FOU
                                                                   11, Contract/Grant No.
                                                                         fcOSfpasd'-
 16. Abstract
   A site was selected at  the Borough of Phoenixville, Pennsylvania,  which provided
   a maximum variable exercise of a pressure sewer system.  The  site  consisted of
   five residences spread  over more than one-half mile in hilly  and predominantly
   shale-based terrain.  The residences varied from a small house  to  a  multiple-
   unit apartment house.   The apartment house is more than half  a  mile  in distance
   and 60 feet in elevation below the existing conventional gravity sewer inlet
   point.
   The project proved over a six-month period that a multiple  residence pressure
   sewer system can adequately store peak loads of wastewater  and  gtiftd and pump
   wastewater through small-diameter plastic pipe to the existing  conventional
   gravity sewer.  During  the project, data was collected which  provided infor-
   mation concerning the 'installation, operation and maintenance of the system,
   its technical performance, the variations in that performance during the six-
   month period and the characteristics of the wastewater as delivered  to the
   existing gravity sewer.
 17a, Descriptors
   *Water pollution control,  *Sewers, *Sewage disposal, Plastic pipes,
   Pressure conduits, Data  Collections, costs.
 I7b.          *pump-grinders,  *Pressure sewers, *Systern monitoring,  Cost
              breakdown, Wastewater characterization.
 17c. COWRR Field & Group
 18, Avaikt-ility
 Abstractor James
 ——^—^—
WRSIC 102 «REV. JUNE 19715
                 	
                 reissl
                                           %2. Price
                                                     Send To:

                                                     WATER RESOURCES SCIENTIFIC INFORMATION CENTER
                                                     US. DEPARTMENT OF THE INTERIOR
                                                     WASHINGTON. DX. 20240
—Environmental Protection agency. Ejatipnaj
.nstituuwuEnvironmental Research Center, Cinti,0hio
                                                                                Q P Q  488-935

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