\V A II R I'Ol.l.l T1ON CONTROL RISI ARC II SI RMS 11020 DHQ 06/72
GROUND WATER INFILTRATION
AND INTERNAL SEALING
OF SANITARY SEWERS
MONTGOMERY COUNTY, OHIO
I'.S. KNVIKONMI N I Al. I'KO I K( 1ION A(;KNCV
-------
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 water research program of 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, DC 20460.
-------
GROUND WATER INFILTRATION
AND
INTERNAL SEALING OF SANITARY SEWERS
Montgomery County, Ohio
by
Montgomery County Sanitary Department
U221 Lamme Road
Dayton, Ohio 15439
for the
Office of Research and Monitoring
ENVIRONMENTAL PROTECTION AGENCY
Project #11020 DHQ
June 1972
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 • Price 75 cents
-------
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 recommenda-
tion for use.
ENVIRONMENTAL PROTECTION AGENCT
-------
ABSTRACT
A program for pollution abatement was undertaken by the Montgomery
County Sanitary Engineering Department in Southwest Ohio to research
the effects of infiltration reduction by joint sealing and to study
closed circuit television techniques.
Water pollution from municipal wastewater treatment plants would be
reduced if peak flows from rainfall could be reduced. This study
evaluates the effects of remedial repairs to joints by use of pressure
grouting of small main line sewers. A minimal measurable amount of
quantity flow reduction was attributed to the sewer sealing program.
This is to say that infiltration from extraneous storm water, illegal
connections, and basement underdrains seem to .outweigh the contri-
bution due to leaky joints.to such a degree that reduction due to
joint sealing was obscured.
The study does show the significance of internal television system
as an inspection and maintenance tool. This information on costs,
operation, and procedure is of value to anyone interested in this
field.
This report is submitted in fulfillment of Project #11020DHQ under the
partial sponsorship of the Water Quality Office of the Environmental
Protection Agency.
111
-------
CONTENTS
Section Page
I Conclusions 1
II Recommendations 3
III Observations 5
IV Introduction 7
V Program Design 9
VI Conduct of Experiment 27
VII Discussion 33
VIII Appendices 39
-------
FIGURES
Figure Page
1 Study Area Selection Flow 5 Rainfall 11
2 Ground Water Test 12
3 Soil Conditions § Sealing Summary 13
4 Method of Checking Surcharge 14
5 Method of Checking Surcharge 15
6 Study Area 17
7 Ground Water Characteristics 19
8 Rainfall vs. Flow April 1970 20
9 Infiltration-Exfiltration Cycle 21
10 Normal Flow. Day 22
11 Flow Meter Design 25
12 Determination of Ground Water Profile 28
13 Rainfall vs. Flow April 1971 30
14 Rainfall vs. Flow June 13, 1970 31
15 Rainfall vs. Flow April 27, 1971 32
16 Pre-Sealing, Post-Sealing Comparison 36
17 Sealing Speed vs. Sealant Used 46
18 Power Winch Schematic 61
19 Method of Triangulation 64
VI
-------
TABLES
No. Page
1 Ground Water Index 68-69
vii
-------
SECTION I
CONCLUSIONS
1. Sealing is an effective process. Rechecking joints after one
year revealed no deterioration. See pages 9 and 37.
2. Sealing and televising costs and speeds depend greatly on line
conditions and operator experience. See page 59.
3. Televising should precede sealing unless condition of the lines
is known, (new lines)
4. The ratio of peak load during a surge due to rainfall to average
load exceeded 7 in the study area. See page 32.
5. The sealing of the trunk line joints was not proved to be an
economical means of reducing overall infiltration. See Appendix B.
6. Television inspection is an extremely useful tool to determine
pipe condition and location of features. See page 36.
7. Television inspection of joints is not an effective method of
determining joint condition. See Appendix I.
8. Television inspection revealed many defects not apparent through
smoke testing. See page 10.
9. Sewer sealing would not remove the instant peaks in flow (infil-
tration due to downspouts and illegal connections) but it is possible
to remove the long tailing off period after rainfalls. See page 23.
10. The technique of pressure grouting, although slow, cumbersome,
expensive, and requiring technical expertise, is a permanent, effective,
and economically superior method to digging. Results with this method
can be-checked and documented, and hence is extremely reliable. See
page 37.
-------
SECTION II
RECOMMENDATIONS
1. Unusually low rainfall during the experimental phase of the study
may have affected results. Further investigation is warranted. See
page 34.
2. An aggressive program to remove illegal connections should pre-
cede any program of this type. Infiltration from other sources ob-
scure results. See page 32.
3. Any future work of this type should be performed in a manner that
insures legal support of the activities necessary to run the experi-
ment. See page 32.
4. Development of a more effective method of monitoring ground water
conditions is necessary. See page 33.
5. Development of a method to measure and record lateral flow is
necessary. See page 33.
6. Domestic water flowing into the study area should be metered
directly. Frequent house meter readings proved to be impossible
due to the objections of study area residents. See page 33.
7. In order to compensate for any other factors which may enter into
the study and confuse the results, it is suggested that in the design
of future studies an adjacent area be selected, fitted with a flow
meter, and serve as a control area. See page 34.
8. In the future studies consideration should be given to the selection
of a compound flow meter. Flows differing from those anticipated
result in the loss of valuable information due to the inability of the
flow meter to measure fluctuating flows. Accurate and precise measure-
ments of the flow conditions over the entire range will enhance
results. See page 32.
9. It is desirable to set up a standpipe connected to each monitor-
ing manhole invert with a float and a recording device. This would
enable the flow design index to be a more realistic figure. See
page 23.
10. A very rough figure for design can be obtained by finding the
ratio of the treatment plant peak flow to the plant flow at 8:00 A.M.
and then applying this ratio to the study area flow at 8:00 A.M. to
get a projected figure. See page 24.
-------
SECTION III
OBSERVATIONS
1. For estimating purposes overall sealing speed during the project
was 72 ft/hr/306 ft/day. The cost was $5.79 per joint. Televising
cost for the overall project was $1.54 per foot. See Appendix B.
2. The power winch mechanism aids in the speed and economy of the
sealing and televising process and permits the use of a three-man
crew. A two-man televising crew can televise under ideal conditions.
See page 37.
3. The flow-through packer design does not require the pumping of
sewage arourd the area being sealed.
4. Only after periods of continuous rain will the ground saturate
and the ground water move upward. After the ground is saturated,
moderate rainfall will move the ground water up quite markedly. See
page 26.
5. Ground water pipes tend to clog, adversely affecting the relia-
bility of the readings. See page 18.
6. A four-wheel drive vehicle is necessary for this type of work.
See page 59.
7. This report can be used most effectively in the areas of cost,
equipment, procedures, and organization. See page 36.
-------
SECTION IV
INTRODUCTION
Extraneous water entering sanitary sewer systems reduces the effective-
ness of both the collection system and the treatment facility. Ideally,
this water should never enter a sanitary sewer system. In reality,
however, such water does enter the system through a variety of ways.
A sewer system which had none of this water would operate more effective-
ly because the total volume of water throughout would be reduced to a
minimum. Extraneous water enters a sanitary system through the follow-
ing ways: illegal connections, cross connections, underground infil-
tration, and incorrect uses. It causes surcharges destroying treatment
equilibrium in biological processes and reducing the degree of treatment
achieved by a wastewater treatment plant. Surcharges flood trunk and
connector systems disrupting service by users as well as causing
basement backup. Besides flooding basements with diluted sewage,
causing a health hazard, the system untreated wastes are discharged
directly into natural watercourses through a system of by-passes.
If it were possible to prevent entry of extraneous water, the treat-
ment facility could be designed to treat only the effluents of the
users. There would be no need to provide capacity in the treatment
plant and the collector system for infiltration loads. Thus reduction
of the amount of extraneous water results in more efficient operation,
lower capital expenditures, and lower stream pollution levels. Since
the sources of this unwanted water are varied and complex, the methods
to reduce its level are equally complex.
In order to determine a solution, the problem must be defined. There
is a need to know, quantitatively, the amount of infiltration coming
from various sources and the cost effectiveness of respective remedial
action. It is not feasible to generalize between the sources of in-
filtration in various systems, or even various locations in the same
system due to the wide variation in conditions. Expertise in the
effectiveness of different solutions is lacking.
Where corrective action has been undertaken to alleviate basement
flooding caused by infiltration problems as maintenance procedures,
sufficient controls could not be established to determine the actual
effectiveness. In addition there is a need to relate such parameters
as the intensity and duration of rainfall, ground water table, soil
composition and moisture content, joint type, material type, and normal
flow characteristics to the infiltration problem. The best indicator
of overall infiltration has been a comparison between total water
pumped from its source into an area, and sewage flow from a particular
drainage area. Graphs of these flows show a cyclical shift between
infiltration and exfiltration which may be correlated roughly with
wet and dry periods. These figures are not totally indicative of the
quantities because of allowable meter inaccuracies, process water
consumption, extraneous water use, i.e. swimming pools, street
-------
washing, fire fighting, watering, car washing and by-passes in the
sewer system.
The Beavercreek Sewer Subdistrict of the Gre'ater Moraine-Beavercreek
Sewer District of Montgomery County, Ohio, has been plagued with in-
filtration problems and resulting surcharging of its treatment plant
since its establishment in 1952. The County began a corrective
program of remedial action, in 1957, on the effect of sealing trunk
sewers on treatment plant flows.
Because the sewer sealing program was an integral part of normal
maintenance operations accurate cost control procedures were not
utilized. Smaller size collector lines tributary to the trunk sewer
lines sealed contributed such a large volume of flow as compared to
the quantity removed by remedial sewer sealing the effect was not
assignable. It was with these factors in mind a totally new program
was structured. Due to the portion of infiltration assignable to
smaller lines a more significant contribution to infiltration abate-
ment could be realized. In smaller lines a contributary area could
be readily defined and measured without adjustment for flow from ad-
jacent areas.
In 1968, Montgomery County initiated a three-phase program to eliminate
stream pollution: expansion of the wastewater facilities to a capacity
sufficient to treat peak flows, construction of two miles of primary
trunk sewer to replace existing inadequate pipe, and removal of the
source of illegal storm water by inventory of the existing facilities
and embarking on an active sewer sealing program.
Montgomery County Sanitary Department submitted a grant request to the
Federal Water Quality Administration, under the now Environmental
Protection Agency, to study the limited effectiveness of sealing the
small diameter collector sewers in a limited study area.
-------
SECTION V
PROGRAM DESIGN
The study required designing a program to determine the effectiveness
of sealing on infiltration. Sealing of defective sanitary sewers
can be accomplished internally by chemical means. Two types of sewer
sealing were considered.
One process includes the instantaneous mixture of two chemicals at
the point of injection in the leak in the sewer. The chemicals are
forced through the crack in a defective piece of pipe joint and into
the earth surrounding the sewer pipe. This material permeates the
earth backfill and forms a gel in the void areas in the soil. High
pressures are required to mix and inject the chemicals; consequently,
this type is known as the pressure grouting process.
A second type of liquid sealing of sanitary sewers is to mix the dry
materials in an isolated section of the sanitary sewer in large
quantities of water to form a slurry. The upper manhole is filled to
a height at least four feet above the outside water table. The solu-
tion is then forced through the cracks in defective pipes and joints
by hydraulic pressure. The particles in the slurry attach to the edges
of the leak and/or soil particles in the backfill. The solids in the
slurry absorb water and expand to seal the openings.
As we worked on the first phases of the project there was one basic
change in our plan. This was the limitation to a single method of
sealing, pressure grouting, and the one particular acrylamide sealant
used with it. Our reasons for this were, first, the two methods,
hydrostatic and pressure grouting,, are sufficiently different so that
the effectiveness must also be different. If more than one method
were employed in a single section then it would be impossible to
evaluate their individual effectiveness. Secondly, the pressure in-
jection method gives the opportunity to test each joint under pressure.
It is known that each joint is positively sealed and its condition a
matter of record. This method also allows the recheck of each joint
after the program to insure conditions did not change during the course
of the experiment.
A review of the entire system was conducted to select a suitable test
site. Although an entire system may be faulty, a specific area had
to be selected where the various effects could be measured.
The next step was to check the individual test sections in detail and
make a final selection. The factors used in selecting a test area
are reviewed in Appendix B. This entailed watching the relationship
between rainfall and flow. This was done as often as possible after
significant precipitation and occasionally during dry weather. It
was important to go out at the same time every day to get significant
readings. It would have been better to have temporary flow gauges
-------
with 24-hour charts using an in-pipe flume or a stilling well connected
to the invert of the pipe. This was not provided for so that the ruler
spot check once a day was used. It is necessary to consider that the
pipes flow at different grades in order to compare this information.
The monitoring location must also have sufficient straight run of pipes
with no drops to assure laminar-flow for accurate measurements. In-
spections were also made at night during low flow to observe the actual
extent of infiltration. The areas were small enough to observe any
nighttime flushing activity, so any flow observed was assumed to be
infiltration. Infiltration flows are generally clean and clear and
flow continuously. The results of all the flow checkings are shown
in Figure 1. During this selection period we did not allow for water
softener backwashing.
Each area was smoke tested for illegal connections or bad defects.
None of our smoke tests showed any defects although further television
investigation found many.
Ground water level monitoring pipes were installed in varying manhole
locations in the prospective area and extended approximately one foot
below the invert of the pipe, as shown on the detailed drawing in
Figure 2. They were checked using a float on a light fishing line with
the manhole rim as an elevation reference. This was done every time
the flow was checked: after every rainfall and occasionally during
dry weather.
Knowledge of existence of ground water is an important part of study
area selection, because we are sealing the pipes to prevent infiltration
which will not exist without ground water. It was important to install
more than one pipe in the sections that looked suspicious because
impervious layers in a trench could prevent water from entering the
pipe.
An independent testing lab was employed to test soil conditions of
these test areas. Tests on the site selected are shown in Figure 3.
Installation of a device for determining if the manholes in the area
surcharge was an important item because any area which surcharges will
obscure the flow measurements at the very time that they are most
important; peak flow due to rainfall. Figure 4 shows cans installed
at different elevations to determine if surcharging occurred. These
cans are not the best solution to surcharge checking as they rust out
fast, fill with water that drips in through manhole covers and are
hard to empty when full. A better solution is shown in Figure 5.
In our final selection surcharging and high flow during heavy rain-
fall were given the greatest weight for selection with ground water
next in importance.
The other factors involved in selecting a test site were the selection
of an area having at least one mile of isolated sanitary sewer,
10
-------
STUDY AREA SELECTION
FLOW a RAINFALL
M—f-t-tt—i—'->-4 •— -M-t
-*--*- -* t— I—•—t- * * • - -I i 4- »
26
Apr
^ 7 10 13 16 I
May
25 2831 3 6 9 12 15 18 21 24 27 30
Days
1969
-------
GROUNDWATER TEST
PIPE IN SIDE OF M.H.
WATER
PLUG
CAP
CLEAR -
ENCE IF
POSSIBLE
7J»n
I" PIPE WITH
THREADED
END
hi
3' (APPROX.)
-------
SOIL CONDITIONS AND SEALING SUMMARY
Scale
l"= 300'
\o\ - Groundwoter pipe locations with no
percolation into soli
- Soil boring locations 8 soil
characteristics
(— Gallons of sealant per foot used
In each span
Fig. 3
13
-------
METHOD OF CHECKING SURCHARGE
I QT. OIL CAN
OR EOIV.
Fig. 4
14
-------
METHOD OF CHECKING SURCHARGE
RATCHET ON
TOOTHED WHEEL j
TOOTHED WHEEL
BEAD CHAIN (PLASTIC
AVAILABLE)
HEAVY COATING OF GREASE ON CHAIN (IF METAL) AND RATCHET
Fig. 5
15
-------
constructed before premium joints were in use, where an infiltration
problem was known to exist. The area selected historically surcharged
and flooded basements.
Investigate if removal of illegal connections to the system and other
obvious sources of storm water was possible.
Site should be such as to allow establishment of base data on rain-
fall, ground water, trench conditions, run-off, and sewage flow through
a wet season into a dry season.
Inspect the sewer by internal television inspection and seal the sewer
collector system 100%, testing each joint for leakage, keeping accurate
records of procedures, difficulties, time and materials used.
Considering these factors the site was selected. See Appendix B.
Figure 6 indicates the final study area's layout.
After selection of the test study area was finished, the investigation
continued so that a more complete knowledge of test conditions could
be determined.
The study area is of entirely residential usage except for a dairy
store which was constructed after the flow meter was complete. There
are 152 houses tied into 6500 feet of vitrified clay sewer in 24 spans.
The following is a summary of the physical characteristics of the houses
contained within the study area.
18 crawl space - 33 slab - 101 basements
5.3 rooms average
6% - 1 bedroom: 22% - 2 bedroom: 65% - 3 bedroom: 7% - 4 bedroom
92% - 1 bath: 6% - 2 baths: 2% - 3 baths
13% dishwashers
91% clothes washers
26% water softeners
3.8 people per house
Run-off conditions: Land Area: total drainage area: 1,513,700
square feet area served by curbed streets and storm sewers: 1,409,600
square feet.
Roof Area Drainage
Roof Area 184,773 sq. ft.
No Downspouts 10,706 sq. ft.
Downspouts piped into ground: Outlet free: 42,538 sq. ft.
Outlet plugged: 21,659 sq. ft.
No visible outlet: 16,188 sq. ft.
Direct downspout drainage on splashblocks: 93,681 sq. ft.
16
-------
WINDEMERE OR
WILLAMET RD.
Scale
l"»300'
TO
O
STUDY AREA
Fig. 6
17
-------
Total roof area: 184,773 sq. ft.
Sidewalk area: 21,760 sq. ft.
Hard driveway area: ,-.,.«-. ^
Gravel driveway area:
Street area:
No storm or curb:
X U"t , / / *J OV^ . I. IP .
21,760 sq. ft.
131,349 sq. ft.
14,346 sq. ft.
164,747 sq. ft.
23,570 sq. ft.
Soil borings and permeability tests were done in the area to determine
the type of trench backfill material and how it percolated water.
As was expected, the trenches had been backfilled with the excavated
material, predominately clay and silt. All the permeability tests
showed no percolation of the water into the soil. The results of
these borings are indicated on Figure 3.
Although the permeability tests and soil tests showed that the move-
ment of ground water in the area should be quite slow, the ground water
pipes located in the manholes showed that there is a response to
rainfall reflected in the height of the ground water in the vicinity
of the trench.. Pipes as shown in Figure 2 were installed in all the
manholes in the area and checked as soon as possible after rainfall.
They were also tested to see if they worked by filling them with water
on several occasions and watching the drop in water level. In locations
where the pipes were shown to be clogged, new ones, and ones through
the sides of the manholes, were installed. These were also tested.
When the tests showed to be negative certain locations were rejected
for ground water data.
The graph of the ground water characteristics, Figure 7, shows the
location for taking the readings of ground water in the operating
ground water pipes, determining the height of the ground water above
(+) or below (-) the invert of the pipe in each location. These heights
were then averaged (using levels above the invert as positive (*)
and below the invert as negative (-) to get an index of ground water
conditions). This index, shown in Figure 8, is superimposed on a
graph of the nighttime flow, at 3:00 A.M. and rainfall. Clearly, rain-
fall influences ground water level in the trench.
As an overall check on infiltration-exfiltration, individual house
water meters were read in the study area nearly every day. The
intention was to relate these readings to the total flow in the study
area. Because of problems with the flow integrator on the flow meter
this became impossible. An overall indication can be taken from this
comparison for the whole Beavercreek drainage area, found in Figure 9.
This graph shows a large amount of water in the sewer above water
pumped during the rainy season, presumably from infiltration. During
the dry season equally as much water is unaccounted for, due to water
used for nonsanitary purposes and exfiltration.
The flow response to rainfall in our test area was quite dramatic.
Figure 10 shows an average day in which low flow and no rainfall
conditions existed. In the early hours of the morning constant flow
18
-------
GROUNDWATER CHARACTERISTICS
WINDEMERE DR
LISBON ST.
. HARWOOD AVE.
ANNABELL OR.
Scole
I" =300'
H
O
• - Ground wo ter pipes that did not
take water when filled to top
&- Pipe locations used In ground-
water overage height
Fig. 7
19
-------
RAINFALL v* FLOW
,--- '10
U !--
I I . fl C
( • I t , «?-«'
i i i.i ' i i t
} f I -1 IT !: i
1
-------
INFILTRATION-
jjj -r-300
£
200
-100.
1968
c a
Oi »
!31 1*-
1969
I
Infiltrotion
*( excess sewage treated
to water pumped)
1970
,00
^.200
.300
Ex flit ration
"*"(loss of water
from system)
Sewage; from plants l,3,a 6
Woter from Greater Moraine System
Includes losses due to: watering lawns,
filling swimming pools, industrial
losses, etc.
-------
NORMAL FLOW DAY
1
AM 1
P— -"
^
2345671
,— d
r±
^
^
i <
I 9 10 II 12
Hours
March 16,
hHMM
•"j^
S;
^
^d
^
— i
^
!=>H
•™=^
^
i
2345676 9 10 II 12PM
1970
3c
.9
3n
0 Q Rainfall
Inches
IE
i rv
. 1 *\C\
100 Flo*~
G.PM
- *?o
-------
indicates that there is infiltration in the area all the time. The
magnitude of this constant infiltration flow is influenced by rain-
fall and,a feeling for it can be gained by looking at a graph of
flow at 3:00 A.M. superimposed on rainfall and ground water index.
On days when large volume, high intensity rainfall occurred, tremen-
dous jumps in flow were observed. These were transcribed onto ex-
panded scaled graphs to show the hour-by-hour flow characteristics
and rainfall.
There are two basic types of rainfall with corresponding effect on
flow. The first is the relatively short, high intensity rainfall
which causes the flow to jump up suddenly and then drop back to normal.
This occurs even when the trench ground water index is low and when
the rainfall has no effect on ground water. This indicates that there
are relatively direct connections between sources of surface water
and the sanitary sewer. The suspect is naturally the basement drains.
When the rain intensity reaches a point where the surface run-off
is not removing the water rapidly enough then water begins to build
up around foundations. :House lateral taps drain this off into the
sewer. The ground water level in the trench has no effect on this
type as it is shown. The second type of high flow is due to an ex-
tremely heavy and long rainfall in which the ground water index jumps
up and the flow takes more than a week to return to normal. Sewer
sealing should not remove the instant peaks in flow due to high in-
tensity rainfalls although it is possible that it may remove the long
tailing off period after high volume rainfalls.
A totalizing rain. guage was installed in the study area to obtain
a more accurate measure of rainfall in the area. Readings from this
gauge, run 24 hours, are used throughout the data.
There were three criteria for design of the flow meter. First, the
recorder must have sufficient capacity to record any high flow that
might occur during periods of heavy rainfall and high ground water
table.
Secondly, a 24 hour chart to correspond with the rain gauge and give
sensitive results of the response to rainfall must be provided.
Finally, the recorder must have sufficient accuracy at low flow
(normal days) to record day-to-day flow with some accuracy. This,
however, was a good deal less important than the high flow data.
The low flow data for an area with about 150 houses was taken from
a chart of daily, average and peak flows vs. number of residences.
The numbers for modern residences with nominal infiltration were:
peak flow, 225 gpm; average flow, 40 gpm.
The high flow design figure in the area had to be a combination
of judgement and the maximum reading recorded while checking the four
study areas for selection. It would have been desirable to set up
a standpipe connected to each monitoring manhole invert with a float
23
-------
and a recording device, but this was not done. The information showed
a depth reading of .35 feet in an invert of an 8 inch pipe at 3.32%
grade (492 gpm). This was taken at 8:00 A.M., 6-1/2 hours after the
rain ended (.45 inches from 1:00 P.M. to 5:30 P.M. and 1.65 inches
from 11:15 P.M. to 1:30 A.M.). So it was not the actual peak flow.
A very rough figure for design could have been obtained by finding
the ratio • of the treatment plant peak flow to the plant flow at
8:00 A.M. and then applying this ratio to the study area flow at
8:00 A.M. to get a projected figure. When doing this the amount of
high flow by-passing must be taken into account and an estimate added
to the plant before calculating the ratio. This method was also
impossible as the meter at the plant was off scale and there was no
way of measuring the massive overflow, because the flow was beyond the
limits of the meter.
Therefore, it was necessary to use the flow measurement and make a
judgement about what the maximum flow would have been. The sizing
was also affected by trying to keep the meter as sensitive as possible
to low flows. The capacity of the upstream line was checked and found
to be 560 gpm. This was close to the 492 gpm observed so 500 gpm
full scale was chosen. With the 20:1 calibration available with the
meter, the low flow calibrated figure would be 25 gpm. This was
decided to be the best compromise. A 3 inch parshall flume was used
because it would carry up to 800 gpm, well above the capacity of the
upstream pipe, even though the recording device would only be cali-
brated for 500 gpm.
The flume is a prefabricated fiberglass design which was cast solid
on concrete in a precast concrete pit. See Figure 11. The sending
unit is an in-channel float using a mill balance bridge system to
operate the chart indicator needle. The chart and drive is located
in a weather proof box with a built-in heater. The system of flume,
sending unit, and chart mechanism were provided by Badger Meter
Company.
24
-------
TOP
10'(
.5%
INV.
949.1
SIDE
FLUME RECORDER 8 SENDING UNIT
BY BADGER METER CO.
PRECAST
CRETE VAULT
WITH STEEL
DOORS SET IN
CONCRETE TOP
FLUSH WITH
GROUND
ADJUSTABLE
BRACKET
WEATHERPROOF
RECORDER WITH
INTERNAL HEAT-
ING UNIT. 24HR.
CHART (500GPM
FULL SCALE)
WATERPROOF
FLOAT TYPE
SENDING UNIT
8 ® 1.45%
INV. 948.97
3 PREFABRI -
CATED PAR-
SHALL FLUME
CAST IN CON-
CRETE
FLOW METER
Fig. II
25
-------
SECTION VI
CONDUCT OF EXPERIMENT
Having completed the preliminary work, the experiment continued.
An estimate was made as to the cost of sealing and televising. Our
experience in sealing and televising is included at the end of this
report. Appendix C is the Projected Sealing Cost; Appendix D, Actual
Sealing Cost; Appendix E, Sealing Crew and Operation Procedures;
Appendix F, Sealing Equipment; Appendix G, Equipment Recommendations;
Appendix H, Special Details of Sealing Operation; Appendix I, Methods
of Determining the Need for Sealing; and Appendix Jf Description
of Grant. This information is valuable to anyone interested in the
operation of this equipment.
As stated in the foregoing, the primary interest in the data on
ground water was how much of the pipe line was under the water table.
To do this an index was arrived at by which the height of the water
in the hydrostatic columns referenced the invert of the sewer. In
order to correlate this parameter with the rainfall data some general
average for the water table had to be stated. Originally, an arithmatic
average of the indexes was used. This presented virtually an unus-
able gauge of the water table activity because soil conditions at a
few pipes gave a negative reading and negative and positive readings
tended to cancel each other. The negative readings did not necessar-
ily mean the absence of ground water either. There was reason to be-
lieve that the action of an underground stream running through the
study area created draw-down on certain adjacent pipes, so that some
pipes apparently went down during heavy rains. Although the average
index went up during heavy rains,, this average index could not be use-
ful in stating that, on the average, the line was submerged.
A rather burdensome solution to this problem, but the most satisfy-
ing, was to plot the height of ground water on a scale profile draw-
ing of the sewer for each reading of the ground water. This gave a
graphical display of the ground water grade superimposed upon the
sewer, showing clearly how much line was submerged. This method is
not without shortcomings, for pipes which were clogged would make
sections of the ground water grade indeterminant. "Figure112 is:an
example of the method used. For the sake of space, Appendix K,
Table 1, gives this information in percentage of line submerged, which
is the result of this graphical method.
It will be noted that the absolute amount of rain or its intensity
does not produce proportional results in the vertical movement of
ground water. When the ground is dry, water is taken up in the soil
and the ground water hardly moves. Only after periods of continuous
rain will the ground saturate and the ground water move upward. After
the ground is saturated moderate rainfalls will move the ground water
up quite markedly.
27
-------
DETERMINATION OF GROUNDWATER PROFILE
IS)
oo
Procedure-.
A. Plot Groundwoter Table Elevations, A 8 B. (See Groundwater Pipe Diagram)
B. Connect Lines (to approximate GWT profile).
C Estimate % of Line Under GWT
Percent Under GWT =(-
100)
Where:
GWT = Groundwoter Table
LGWT= Length of Span Under GWT
Ls= Length of Span
A = Elevation of GWT in Well A
B = Elevation of GWT in Well B
-------
Sewer flow in the study area was monitored continuously through the
base data collection and after sealing, with the exception of the time
during sealing which was a dry period. The flow is plotted against
rainfall and average ground water index for 3:00 A.M. in Figure 8,
before sealing, and Figure 13, after sealing. The 3:00 A.M. flows
were used because this is a period of practically no usage of sani-
tary facilities so that any flow is attributed to infiltration.
It might be noted that in the selection of the study area this assumption
was ill-founded. There are devices such as water softeners in any
area which discharge enough water in recharging, specifically during
periods of sanitary inactivity, to present a significant flow (60-80
gal/unit). The presence of this source can be confirmed by checking
chloride content of the sewage at that hour. For this reason, it is
possible that there was not a constant infiltration in the line
through the collector system;
The high flows coincident temporarily with rainfall do not necess-
arily mean infiltration. It takes a short time for direct storm
water sources (downspouts and draining manholes) to have their water
reach the flow meter; typically, five minutes. Infiltration, where
the water has to travel through the earth, will be delayed both in
onset and decay. This is most easily seen on the expanded flow
chart which plots flow by the hour against rainfall for each incidence
of rainfall. Figures 14 and 15 are before and after sealing, respec-
tively. The expanded graph clearly shows that after the end of rain-
fall and after a reasonable period of delay for manhole drainage, there
is clearly an infiltration which stays up (3:00 A.M. constant flow)
and slowly decays to a normal flow.
29
-------
RAINFALL vs FLOW
17 is /9 £0 21 £.- 23 ?'f ?J 21 :. *:' -?•; 3?
3:6?"
f7ou> -
G.PM.
APRIL 1971
-------
RAINFALL vs FLOW
7 8 f so '/ /X / * 3 V f * r
June
13, 1970
4.0
-------
RAINFALL vs FLOW
cn
APRIL
'ots/-j
27, 1971
4.0
3-f
3.0
z.r
>.o
fftc/re.9
/.ff
/.o
.f
-0 £00
/ff£>
-/C0
— so
-------
SECTION VII
DISCUSSION
It is the purpose of any research project to extend the knowledge in
a particular field beyond that which is presently known. This report,
on sewer sealing, provides information and conclusions which add much
to this field of knowledge.
Typical of *he important information which has resulted from this
study is the ratio of peak flow to average flow. It is a current
engineering practice to allow 10% oversize capacity for flows result-
ing from infiltration. Within the study area, a typical residential
sanitary sewer system, the ratio of peak flow to average flow ex-
ceeded 7. This is significantly higher than had been anticipated,
and gives some interesting insight as to the cause of overflows and
the significant amount of sewage currently being by-passed.
The main subject of the research, sewer sealing, turned on several
factors. Among the requirements for a successful study were the
isolation of infiltration due to faulty or leaky joints, the dupli-
cation of all other significant conditions before and after sealing
of the joints, and the comparison of flows prior to and after sealing.
Any compromise in any of these key factors would damage the validity
and dangerously discredit the results of the program.
The isolation of infiltration due to leaky joints proved more diffi-
cult than had originally been anticipated. Chief among the require-
ments were the selection of a suitable flow meter and removing as
much of the infiltration from sources other than leaky joints as
possible. Although much effort had been given to the selection of
a proper flow meter, the selection was not within the precision,
accuracy, and range to prove most effective for this study. In any
future study, consideration should be given to selection of a com-
pound meter. Flows exceeding those anticipated resulted in the loss
of valuable information because they were greater than the flow meter
could measure. The significance of the low flow characteristics were
not fully appreciated. Accurate and precise measurements of the flow
conditions over the entire range would have enhanced results.
Another significant factor which was extremely difficult to overcome
was the attitude of the residents of the study area. Although there
are legal regulations which cover illegal taps and storm connections
to the sanitary sewer, no amount of legislation can insure a favorable
attitude. The distaste of the residents toward the chores of setting
up the experiment and the routine business of collecting data resulted
in the loss of valuable information. Any future work of this type
should be performed in a manner that insures legal support of the
activities necessary to run the experiment. Gaps in the collection
of data can result.
33
-------
The problem of properly connecting downspouts to the curb or to a
storm sewer was also significant. This action is necessary to insure
that this source of possible infiltration is removed. Although this
connection is illegal, the only way to test is to smoke test. The
validity of this technique is questionable.
Floor underdrains are connected to the sanitary sewer under present
regulations. The load resulting from these connections is not known
and should be measured. The only method devised, although untested
due to cost and owner attitude, would be to physically reconnect
the sewer lateral to a sump pump. The pump could record the electrical
consumption and an energy balance should reveal the amount of water
pumped.
When an experiment is carried out in a laboratory, the duplication
of control conditions is easy compared with the requirements of a
field study such as this. The duplication of all conditions was
hampered by a very low precipitation year. The weather during the
presealing period was never anticipated to be exactly that of the post-
seal ing 'period, but they were hoped to be comparable. Such was not
the case. Subsequent to sealing, the ground water table lowered to
such a level to prohibit comparison. This condition is not a local
factor, but regional. The water table of the entire river diminished
in excess of forty feet during the same time period. The soil com-
position of the study area, primarily sand and gravel, makes the ground
water table extremely sensitive to precipitation. No economical sub-
stitute to recharge the ground water table in the study area was de-
vised. Sufficient rainfall to recharge the ground water table is not
anticipated in the time limitation of the report.
The method of measuring ground water also proved more difficult than
had originally been anticipated. Two methods were used. Five deep
wells of three inch diameter pipe were bored adjacent to the main
line, twenty feet from the manholes, to a depth of four feet below
the invert. Every manhole was provided with a ground water pipe
drilled through the base or through the side to allow the determination
of the water level. The ground water pipes tended to clog, adversely
affecting the reliability of the readings. The results have no pattern
and relationship to all other factors of rainfall, flow, etc., thereby
rendering them worthless. Figure 12 indicates the method in which
the ground water was graphed and the text provides more specific
information. A better method of monitoring the ground water level
near the main line would be of great value in studies such as this.
The amount of domestic water entering the study area is of significance.
The use of the meter readings was not successful because the residents
were not cooperative to the degree necessary, and the collection
of the data is time consuming. The study area could be isolated by
installing compound water meters in the distribution system in con-
junction with check valves. The selection of a device similar to a
Detecto check valve to allow adequate fire flows is recommended.
This configuration would allow comparison of consumption with respect
34
-------
to the sewer flows.
To compensate for any other factors which nay enter into the study
and to more closely correlate the results, it is suggested that in
the design of future studies an adjacent area be selected, fitted
with a flow meter, and serve as a control area. With the results
of the flows from this control area, the presealing and postsealing
conditions could be better compared.
Considering the foregoing, the comparison of conditions prior to
and after sealing was nearly impossible. The comparison, however,
was made and the results were these.
In an effort to convey the information quickly, a bar graph, Figure 16,
was included. This graph indicates the comparison of conditions
measured prior to sealing with those after. They represent the total
flows for the month of April, 1970, with those of April, 1971; The
selection of the proper method of comparison is a difficult task and
the conclusion drawn from a comparison is a difficult task. It was
thought that selection of the same months of the two years for com-
parison would locate the periods in similar positions on the infiltration-
exfiltration cycle. This assumption proved incorrect. A sewer pipe
with leaky joints would logically infiltrate when submerged below the
ground water table and exfiltrate when above. The rainfall during
the time spans considered was only 22.64% of its presealing level
resulting in a drop in the amount of sewer submerged in water. Using
the method discussed in the text, the average portion of the sewer
submerged by the water fell to 59.2% from a presealing high of 88.6%.
Although the reduction in sewage flow to a level only 39.73% of its
presealing level (a level approximately equal to the estimated water
entering the study area through the domestic water system) is an
encouraging result, the reduction in rainfall prohibits crediting the
reduction entirely to sewer sealing. The low rainfall has as an effect
to challenge the validity of the entire program. As previously men-
tioned,, a nearby area could have served as a control to allow for
better comparison of results. At present it is mathematically im-
possible to compensate for the reduction because the mechanisms of the
behavior of ground water levels, underground flows, and exfiltration,
are not known. Until there is a comparable wet period of long enough
duration to allow comparison to the presealing conditions, the results
will not be concrete.
The other factors included on the bar graph are the throughput of the
Beavercreek Treatment Plant and the amount of domestic water pumped.
It is not to be assumed that the areas served by the two systems,
or that of the study area, are identical. These graphs are presented
to describe general conditions. The decrease in treatment plant
activity to 86.93% of its former level, while the water usage rose
8.55% does, however, indicate that the conditions in the study area
were common to the entire Beavercreek system.
35
-------
91 '
\\\\\\\\\\\\\\
\\\\\\\\\\\\
-------
It is an interesting and not entirely false conclusion that infil-
tration by a leaky collector system may benefit the system when the
invert is above the ground water table. During storm surges, the
flows may cause exfiltration which later returns to the sewer during
times of low loads. In this way the total peak load on the treatment
facility and the amount of sewage by-passed may be reduced to a
degree.
As an overview, the procedure selected for this study seemed correct
but control is deemed insufficient. This report can be most effec-
tively utilized in areas of cost, equipment, procedures, and organi-
zation. The judgemental errors which occurred in the design of the
experiment need not be duplicated.
There are several significant items not adequately recorded or even
attempted to record in this study.
Consider the mechanisms of the infiltration in the system. In any
branched system, like the lateral-collector sewer system, there
will be more branches than trunk lines. In the study area, for
example, there are 6,500 feet of eight inch collector sewer and approxi-
mately 12,000 feet of four inch laterals. Water enters the system
in two fashions. An established water level may submerge the pipe and
cause infiltration, as is normally the case with a collector pipe, or
water may be poured through the ground from above and enter the pipe,
as is normally the case with lateral underdrains. However, both types
of infiltration will affect both systems. Some laterals will be nor-
mally submerged and water may enter a collector through a manhole.
For a submerged line, there should be a relationship between the
number of joints and the infiltration potential if it is assumed that
all joints are nearly alike. If infiltration is taking place through
the pipe, there should be a relationship between the diameter of the
pipe and the amount. An infiltration potential ratio based roughly
on these factors yields a ratio of two to one the potential of the
lateral system when compared with the collector system when the entire
system is submerged. All of this emphasizes the need for a clearer
picture of lateral flows.
No satisfactory method was ever devised to measure and record the
contribution and flow characteristics of the laterals except by
television inspection. Estimating the depth of flow on each individual
service, uncovering the lateral to determine grade, and thereby com-
puting the flows, might be suggested as a method. This method is
practical only under specific conditions of minimal consumer usage,
low main line flow, and high ground water table.
A great amount of useful information resulted from the television
and packer used in the study. This equipment can provide valuable
results when properly used. The TV camera by itself has proven its
value in visible inspection, including locating underground features
such as improper taps, line offsets, pipe failure, pipe condition,
obstructions, root invasion, leaks, and illegal cross connections.
37
-------
The TV, when used as a maintenance tool, insured a minimum traffic
hazard because the locations were exact, and failure clearly defined.
The only drawback with TV is that it will not pass through too great
an off-set or through a highly deteriorated line. It was found that
it will pass through nearly everywhere a line could be passed.
Another drawback is that the operator must have expertise in the
use and positive* identification of poor joints is not possible.
The packer is of value when properly used. The equipment used is the
most advanced on the market. The flow-through design eliminated the
need of by-pass equipment and enhanced the effectiveness of the unit.
The use of several lines to transport the grout which is mixed at
the packer eliminated the need to clean lines after use, and the
wasting of grout as compared to the pre-mixed techniques. The fact
that the joint can be tested immediately subsequent to sealing insures
complete sealing. The line can be tested joint-by-joint to insure a
good seal.
The grout used was not evaluated. It was based on manufacturer's
recommendations. It is designed specifically for sewer use and has
a satisfactory historical record.
Rechecking all joints in the study area one year after sealing indi-
cated no deterioration with 100% of the joints holding approximately
20 psi pressure.
The grout was readily handled, easily mixed, stable, and effective.
The amount of chemical grout necessary to seal was reduced by employ-
ing a technique of repeated cycles of injection and waiting for the
gel to set. This technique allows the grout to stabilize to a solid
and reduces over-use.
The technique of pressure grouting, although slow, cumbersome, expen-
sive, and requiring technical expertise, is permanent, effective,
and economically superior to digging. With pressure grouting the
results can be checked and documented, thereby making it extremely
reliable.
38
-------
APPENDIX A
DESCRIPTION OF SYSTEM
The sanitary sewage collection system and sewage treatment plant of
the Beavercreek Sewer Subdistrict were installed and are operated by
the Montgomery County Sanitary Department which is under the juris-
diction of the Board of County Commissioners. The total service area
includes portions of the cities of Kettering, Oakwood, Dayton, and
a very small area in the City of Centerville, and Mad River Township
in Montgomery County. Service is also provided to an area in Greene
County contiguous to the drainage area. Nearly ninety percent of
this district has been developed since 1950. The area is predominately
single family residences of the medium to upper price levels with
supporting commercial establishments and one large industrial com-
plex. The residential areas have modern schools, churches, shopping
centers and parks. There are plans in progress for development of the
small percentage of vacant land remaining.
The sewer district was initiated by establishment of a small plant
by the federal government to serve a federally financed housing
development under FHA to relieve the post war housing shortage. The
original plant consisted of no more than an Imhoff tank with an
unknown capacity. The construction of this small plant provided the
impetus for the County to establish a sewer district to alleviate
the health hazard of inoperable septic tanks in developed areas.
The first large section of Beavercreek Sewer District was established
in 1952. Construction included 43 miles of sanitary sewers and the
first section of the sewage treatment plant.
The original sewer district has been enlarged since the early 1950's
by the addition of approximately 100 miles of sanitary sewer, not in-
cluding the sewer added within the City of Oakwood, Greene County,
and the City of Dayton, which is also served by this system.
The early 1950 project construction contracts for sewers included
single strength sewer pipe with individual joints, hot poured asphalt,
compound and hemp caulking material. Much of the original project
was installed under undesirable conditions of weather and water,
consequently, many of the sewers were faulty after construction was
completed. Large quantities of ground water infiltrated into the
system before any connections were made to the system. An attempt
to enforce specifications by the previous sanitary engineer.
Earl W. Riber, was deterred by legal action.
During and after periods of rainfall, sections of the trunk sewer
would surcharge as capacity in the trunk sewers was surpassed. To
eliminate basement flooding, overflows were constructed in key man-
holes allowing a discharge into the system of creeks and ditches of
the Beavercreek drainage area.
39
-------
The Beavercreek plant was expanded in 1970 to a capacity of 10 MGD
primary and 30 MGD secondary, with additional pumping capacity of
30 MGD for use in cases of high flows due to heavy rainfall. Since
construction of this plant the use of the by-passes has been restricted
to localized areas due to stoppages.
Experience gained in the initial project resulted in establishment
of a strict material and construction specification enforced by an
inspection division of the Montgomery County Sanitary Department.
Projects under the supervision of the County in the mid 1950's were
among the first to require a good quality mechanical sewer pipe joint
and hydrostatic testing of all spans of new sanitary sewer. Specifi-
cations also required high strength sewer pipe to be used in all
installations. This type of control has subsequently produced relative-
ly watertight sanitary sewers.
The original system has presented the greatest problem of large flows
during wet conditions and some remedial actions have been taken in
the plant. The introduction of internal television inspection of
buried pipelines has made it possible to determine the locations of
water entering the sewers. The Montgomery County Sanitary Department
has made use of this evidence to initiate remedial construction.
The department felt that it was in a position, with its past experi-
ence, to establish a productive program to determine the cost, effec-
tiveness, and benefits of rehabilitation of sanitary sewers by internal
sewer pipe sealing.
40
-------
APPENDIX B
SELECTION OF TEST AREA
A review of the entire system was conducted to select a suitable
test site. Although an entire system may be faulty, a specific area
had to be selected where the various effects could be measured.
The Beavercreek area was divided into drainage subdistricts on a
1" = 1000' scale sewer map on which all trunk sewers were outlined.
The map was systematically studied and areas which were near a trunk
sewer and appeared isolatable for sewage flow were listed. Pro-
spective areas were then reviewed on expanded scale maps (1" = 200')
and construction drawings were studied. Every effort was made to select
a representative study area. Five areas were selected according to
the following criteria:
Age: to assure that the lines were installed before construction
and inspection procedures were upgraded and premium joints were in
use, a drawing date of prior to 1954 was used.
length: approximately one mile of sewer line.
Isolation by drainage: no other areas could drain through test sec-
tion so sewage flow could be measured by one meter and so that data
at periods of high flow are not obscured by high flow from another
area.
Suitable metering fall: a minimum grade of 3% or a drop manhole
in the metering line, the area must fall into a trunk sewer of mini-
mum 12-inch diameter. Both provisions are to minimize the danger of
surcharging the meter and losing readings at the critical time of
the study, peak flow. A final condition was that the area contain
no known unusual soil or water conditions.
Visual.inspection with attention to:
Street condition: surface, curbs and storm sewers.
Type of house: slab, or basement, uniformity of type throughout test
area.
Downspouts: manner in which they enter ground.
Nonresidential users.
The test sections selected and their qualifications are as follows:
Imperial, Eureka, Dexter, Male
Age: 1953
41
-------
Length: 5700 feet
Metering drop: 8.83 feet drop manhole into 20-inch line
Streets: bumpy, patched blacktop, no curb
Storm drainage: poorly maintained ditches, only one possible storm sewer
Houses: 75% basement houses, many varied styles
Downspouts: most exit above ground
Non-residential load: none
Ghent, Kerwood, Prentice
Age: 19S4
Length: 4900 feet
Metering drop: 4.2%, then 2.7% grade in 8-inch into 18-inch drop line
Streets: blacktop with concrete curbs
Storm drainage: storm sewers
Houses: no basements, only two or three different styles in entire area
Downspouts: nearly all in ground
Non-residential load: none
Willamet, Kruss, Windemere, Kantner
Age: 1952
Length: 6500 feet
Metering drop: 3% grade in 8-inch into 12-inch line
Streets: blacktop with small amount of concrete, concrete curbs,
except 1000 feet of Willamet which has no curbs.
Storm drainage: storm .sewers except same 1000 feet of Willamet which
has poorly maintained ditches.
Houses: nearly all basements, varied styles
Downspouts: nearly all in ground
Non-residential load: none
Mengel, Kenosha, Villanova
Age: 1952
Length: 3500 feet
Metering drop: 4 feet drop manhole in 8-inch line which leads to 10-inch
line after 1300 feet (exception to criteria).
Streets: blacktop with concrete curb
Storm drainage: storm sewers
Houses: 30% basements with varied styles
Downspouts: nearly all in ground though many curb exits are visible
Non-residential load: none
Other areas were eliminated for the following reasons:
Ghent, Kerwood, Prentice: this area was eliminated early before many
readings were made because it surcharged and there was little flow
variation with rainfall.
Hampton: this area had frequent stoppages with resultant surcharging
of the monitoring manhole when the stoppage released. Even though
42
-------
there was ground water in the section no measurable differences in
flow were noted after rain.
Kenosha: this area was eliminated because Willamet, Kruss, Windemere,
and Kantner were closer to the desired length for the study area.
Willamet, Kruss, Windemere and Kantner were selected because they fit
all the criteria: significant flow increase with rainfall, length,
no surcharging, sufficient metering fall, and ground water in the sec-
tion.
43
-------
APPENDIX C
PROJECTED SEALING COST
A field log was kept of every aspect of the operation, the time and
problems involved. The following are problems which we experienced
and comments on the effect on the sealing operation and the projected
time and cost figures.
Camera lighthead bulb failure.
Roots obstructing line, jamming between packer and camera, obscur-
ing vision and preventing packer from sealing.
Holes punched in packer bladders.
Camera failure.
These are problems, which will always be with the operation and .which
are included in our time and cost figures. We had two camera failures,
only one of which could be traced to abuse. If this frequency of
camera failure persisted a backup camera would be needed.
Chemical mixing.
Packer jamming on laterals protruding into line.
These problems could be eliminated by equipment changes and develop-
ment of an attachment on the cleaning machine for reaming out pro-
truding laterals. See equipment recommendations. These were also
included in our time and cost figures.
Smoke from lighthead due to chemical overspray obscuring vision.
Chemical buildup between camera and packer during sealing operation
due to excessive chemical overspray from packer.
Electrical failure of power winch due to frayed connections.
These problems can be eliminated by experience and care in the use
of the equipment. It is difficult to estimate the time loss due to
them so they tend to make the sealing time overage figure on the
conservative side.
Broken down sections of pipe in line necessitating going into span
from both ends. That is; sealing normally to obstruction and with-
drawing. Then towing cables and hoses through, putting the camera
and packer into the downstream manhole, backing back to the obstruction
and then sealing normally. This time consuming operation can be re-
moved from the sealing crew by immediate repair of such defects by
excavation after their location by the television inspection. The
TV is capable of passing through all but the worst pipe breakdown.
44
-------
This did not happen often enough to significantly affect our time
and cost figures.
Faulty check valves causing packer and chemical lines to become plugged
necessitating withdrawal and cleaning.
This was the most time consuming of all the problems encountered and
can be completely eliminated by installing better check valves. The
time lost because of this is not included in our figures of time and
cost.
Using our time logs of the individual phases of the project and the
problems which occurred to us we developed the following times for
each phase of the operation.
Set up time, in line ready to seal: .75 hours average
Chemical mixing time, until ready to seal: .50 hours average. Average
usage requires one mix per day.
Actual sealing speed while in line: 72 ft/hr average. A high of
184 ft/hr and a low of 18 ft/hr were recorded. A graph of sealing time
vs. amount of chemical used is shown in Figure 17.
Moving time to another span, finish sealing until ready to seal
again: .75 hour average.
Tear down and clean equipment and prepare to leave job: .75 hour
average.
Using these time figures a typical average day can be developed using
a 225 feet average span length.
Transport to job, breaks 1.00 hour
Set up 0.75 "
Span 3.10 "
Chemical mix 0.50 "
Moving 0.75 "
Span 1.15 "
Tear down and clean 0.75
8.00 hours
4.25 hours sealing average day
72 ft/hr x 4.25 hrs = 306 ft/average day
For our projected figures the following changes were made because of
unrealistic conditions in our actual operation.
Increased labor rates, because the County wage scale is abnormally low.
45
-------
SEALING SPEED VS. SEALANT USED
f 1.0.
gal,
^ 'ft
50
100 ft/hr
ISO
180
-------
Inclusion of a four wheel drive vehicle for the tow truck.
Inclusion of an extra camera based on the frequency of failures we
experienced. This may not be realistic as our camera may be defective,
with a corresponding high frequency of failures.
Decreased cost in televising based on the use of the power winch.
Use of a three man crew with a competent sealing assistant. Assumption
that crew is experienced enough to eliminate the need for the project
engineer working in the field.
Elimination of the time wasted in working on defective check valves.
With these changes in mind the following is the derivation of the
projected cost of sealing.
Equipment
Pickup truck
$2000.00
450 workdays
3 yrs
Tow truck (FWD)
$3600.00
450 days
Sealing equipment and parts
$21,000.00
450 days
Gas and oil
$ 4.40/day
8.00/day
46.66/day
3.00/day
$62.06/day
Labor Costs
Head operator @ $4.75/hr
Assistant operator @ $4.25/hr
Sealing assistant @ $3.50/hr
Total
10% fringe benefit
$12.50
1.25
$13.75/man x 8 hrs = $110.00/day
General Maintenance Costs
12 full days/year full crew
(12) (110) = $1320/year(1320
150 days
yr
$ 8.80/day
47
-------
Standby Camera Costs
Repairs
2 x $112
5620'
.939/ft
Camera Depreciation
$6750
450 * $15.00/day
$15.00
5620' = .109/ft
.14/ft
Televising Costs
4 spans/day, 224' long
896 ft/day
$180.40/day - labor 5 equipment 5 gas
$180.40
896.00 = ,20/ft
Line Threading Costs (Clean $ Set Up)
Based on 60% requiring sewer jet to
thread lines
Cleaning Costs
Chemical Costs
Total Projected Costs per foot
Equipment
$62.06/day
306 ft/avg day »
.14/ft
Labor
$110.00
306
General Maintenance
$8.80
306
.20/ft
.024/ft
.10/ft
.39/ft
.203/ft
.359/ft
.288/ft
48
-------
Standby Camera $ Repairs
Line Treading
Televising - Cleaning
Chemical Costs
.140/ft
.024/ft
.100/ft
.39/ft
$1.707ft
All of our cost figures apply to 8-inch lines, in which every joint
is sealed. As noted before the speed of the operation greatly in-
creases as the joints take less sealer so the cost of the operation
is highly dependent on the condition of the lines. See the sealing
chart for the summary of the condition of our lines, Figure 3, Soil
Conditions & Sealing Summary.
49
-------
APPENDIX D
ACTUAL SEALING COST
In our sealing operation a good deal of time was spent learning about
the correct use of the equipment. Certain problems were experienced
which obviously could be and were eliminated as the operation pro-
gressed. A bad labor situation also existed in which the sealing
assistant was not capable of performing all the operational and on-
going maintenance activities that were required of him. He was simply
not suited to the job but was a problem with which we were forced to
live. The general problems in learning about the system resulted in
the project engineer working nearly full time with the crew, also an
unrealistic situation. His time is also included in the costs, and
tends to compensate in speed of operation for the incompetent sealing
assistant. The following is a breakdown of our actual costs, which
were higher than they should have been due to the aforementioned
problems. A projection of costs for a more ideal operation will be
done later.
Equipment
Labor
Pickup truck
$2000.00
450 work days
3 years
Trailer Tow Truck
$2800.00
~4"57I
Sealing and TV Trailer plus spare parts
$21,000.00
450
Gas and Oil
Operator @ $3.37/hr
Assistant Operator @ $3.21/hr
Sealing Assistant @ $3.23/hr
Total: $9.81 x 8
Plus 10% fringe benefit $4.00
Project Engineer @ $40.00/day
Plus 10% fringe benefit $4.00
$ 4.40/day
$ 6.22/day
$46.66/day
$ 3.00/day
$60.28/day
$78.48/day
7.85
$86.33/day
$44.00/day
50
-------
Camera Repair Costs
Repair and freight
3 days labor 5 equipment
depreciation
lost time per repair
$112.00/repair
430.83
$542.83/repair
Cleaning Costs
.10/ft
Televising costs (without power winch)
450 ft/day average
Labor
Equipment
Line Threading Costs
9 hrs 0 $15.00/hr
$ 86.33/day
60.28/day
$146.61/cfay
450 ft/day
$135.00
5620 ft
for 5620 ft (only 60%
were threaded by sewer jet)
Chemical Costs
2100 gallons x 1.023/gal
5620 ft
Total Cost per foot
Labor and Equipment for
31 working days
Project Engineer for
12.6 working days
Total
$4,545.22
554.40
$5,099.62
$5099.62
5620 ft
Camera Repair Costs
(General maintenance was done
on down days because of camera)
2 repairs x $542.83/repair
$1085.66
Cleaning Costs
.32/ft
.016/ft
.39/ft
.907/ft
.19/ft
.10/ft
51
-------
Chemical Costs .39/ft
Televising Costs .32/ft
Line Threading .024/ft
Total 1.93/ft
52
-------
APPENDIX E
SEALING CREW AND OPERATION PROCEDURES
The sealing crew should be composed of a minimum of three men whose
qualifications are as follows:
Head Operator: Ability to keep coherent records. Knowledge of simple
electronics and how to use a V-O-M for trouble shooting. Good mech-
anical ability for maintaining equipment and for operating sealing
and TV controls. Supervising abilities. His job is to coordinate the
use of the equipment, order all chemicals and spare parts as needed,
trouble shoot equipment in case of failure, help keep records, help
set up equipment, operate equipment, and mix chemicals.
Assistant Operator: Identical qualifications except that electrical
knowledge is not absolutely necessary. His job is to work closely
with the head operator in the set up, operation, records keeping,
chemical mixing, and maintenance. He must be able to assume the role
of the head operator on days when he is sick or on vacation.
Sealing Assistant: Mechanical ability for maintenancing equipment.
His job is to aid in the set up of the equipment, help mix chemicals,
clean and maintain the equipment, tend the power winch and generally
perform any work required while the head and assistant operators run
the sealing rig.
During our experience with sealing we developed a set"of procedures
which enabled us to set up, tear down and move the equipment from
one place to the next. Efficient set up is a necessity.
Pre-operation procedures consist of the following: the line must be
televised beforehand in order to insure that all obstructions that
would prevent the passage of the packer are located. Line should
be strung the day before. This can be done by the sealing assistant
while the operation is in progress if there is a hydrant available
for flushing or if the flow is high enough. Otherwise a rodder or
hydraulic sewer cleaner is needed. Chemicals should be mixed before
the men leave for the job. This can be done the night before. Trucks
and all equipment should be gassed up the night before. All necessary
maintenance and cleaning activities should take place the previous
day. Lines should be cleaned within a week of sealing. Often this
can be done when line is threaded.
53
-------
SET UP PROCEDURES
Head Operator
Assistant Operator
Sealing Assistant
Drive van and
trailer to job.
Approach manhole
from downstream.
Stop at downstream
manhole.
Drive slowly to
upstream manhole.
Park at upstream
location. Start
to set up camera,
packer, and rear
of trailer.
Start generator
and compressor.
Continue setting
up camera. Make
connections,
test camera
and lighthead.
Operate power
winch. Lower
camera into hole.
Test lighthead
and check pic-
ture. Set foot-
age meter.
Precede trailer to job
in pickup truck. Set
up downstream winch,
assemble cable pulley
shoe, set up barri-
cades.
Tie cable onto threading
line.
Walk upstream with
trailer, making sure
winch power wire un-
reels without fouling.
Pull cable through
with threading line.
Assemble pulley shoe.
Set up upstream winch.
Plug in power winch
cable, lock power
winch cable reel.
Test power winch,
take up slack in
cable.
Go down in hole
and feed camera into
pipe. Check final
hookup. Set shoe in
hole, lock onto winch.
Precede trailer to
job in pickup truck.
Jhread rope if nec-
essary. Otherwise
help assistant
operator.
Pull downstream winch
cable out to length of
span plus 2 manhole
depths. Loop back to
downstream MH. Stay
with winch downstream.
Pull out winch power
wire reel and start
to unreel power cable.
Hold power wire
securely at down-
stream winch.
Feed cable through
winch. Work to
prevent cable fouling.
Plug in power winch
downstream. Put
cable pulley shoe
in line. Feed cable
onto winch until all
slack is gone. In-
stall dummy manhole
cover.
Go upstream to seal-
ing trailer. And
assist.
54
-------
Head Operator
SET UP PROCEDURES
Assistant Operator
Sealing Assistant
Seal.
Give slack on
power winch.
Give slack
with all hoses
and cables.
Start winding up
cables and hoses
as soon as they
are free.
Wind up cables
and hoses.
Move trailer to
new location.
Begin setup
procedures.
Operate power winch
and write in seal-
ing log.
Go downstream. Take
camera and packer
from assistant.
Load all downstream
equipment on truck.
Drive upstream to
trailer.
Wind up cables
and hoses.
Move trailer to
new location.
Begin setup
procedures.
Maintenance and
activities to in-
sure ease of moving
or tearing down.
Line threading,
chemical readying,
cleaning of truck
and organization
of equipment.
Remove shoe down-
stream. Go in hole,
pull out packer and
camera and unhook.
Pass up to assistant
operator.
Load all downstream
equipment in truck.
Drive upstream to
trailer. Wash camera,
clean camera lens,
clean packer.
Wind up cables
and hoses.
Set up downstream
equipment at new
manhole.
Begin -setup
procedures.
55
-------
Head Operator
PULLING OUT
Assistant Operator
Sealing Assistant
Give slack on power
winch. Give slack
with all hoses
and cables.
Start winding up
cables and hoses
as soon as they
are free.
Cose up rear of
trailer.
Go downstream. Take
camera and packer from
assistant.
Load all downstream
equipment on truck.
Drive upstream to
trailer.
Load all. tools, winch,
shoes, and accessories
on van.
Remove shoe downstream.
Go in hole, pull out
packer and camera
and unhook. Pass up
to assistant operator.
Load all downstream
equipment in truck.
Drive upstream to
trailer. Wash camera,
clean camera lens,
clean packer.
Load all tools, winch,
shoes, and accessories
on van.
Fill 60 gallon water tanks. Mix chemicals
if necessary.
56
-------
APPENDIX F
SEALING EQUIPMENT.
1. The Cues-TV Inspection Trailer incorporates the basic TV system
with the necessary accessory items such as winches, plugs, downhole
equipment, into one unit designed for year round operation.
2. Completely wired 110V AC electronic system for powering the TV
system as well as auxilliary lights and hand tools.
3. Electrically started generator insures instant start operation at
the unit's electrical system.
4. High quality camera, solid state, automatic electronic controls,
3" diameter, external focus control, 650-lines picture, quartz glass
face plate, 400 psi pressure tested housing.
5. Industrial video monitor, 800-lines picture, metal case, dual
video input jacks.
6. Power control unit, displays line voltage, controls line voltage,
registers line cycles, regulates camera light intensity, automatically
regulates camera voltages, operates whole system with single off-on
switch.
7. Skid and light assemblies for pipe sizes 6" to 30".
8. Reel assemblies, allows operations of the reels without discon-
necting the input side, rotary connector, geared hand crank and power
drive, hand controlled positive reel brake.
9. Footage meter, indicates the exact distance the camera is from
the center of the manhole, locates on the cable reel, remotely oper-
ates footage indicator, accurate to + 2 feet in 1000 feet. Mounted
above monitor to continuously display" the footage the camera has
penetrated the line.
10. Camera lighthead, operates submerged, no breaking of glass bulbs,
rugged housing, waterproof connectors, snap-in quartz bulbs, variable
intensity for proper illumination in all pipe 6"" to 30".
11. Camera skid assembly, one yoke for all pipe 6" to 30M, instantly
replaceable spacer plates for varying pipe sizes, tow lift tow assembly,
uses cables to guide over offset joints, dual tow cables eliminates
camera rollover, quick disconnect snap hooks, stainless steel runners,
designed to keep camera in middle of pipe.
12. Television transmission cable, designed for sewer TV camera,
heavy duty 1/16" polyurethane jacket, cut resistant, wear resistant,
lightweight (10 Ib per 100 ft), five circuits, quick disconnect
57
-------
connectors, 400 psi, one continuous 500 ft length.
13. Hand winch, sets up over manholes, 500 ft stainless steel cable,
approximately 40 Ibs weight.
14. Power driven winch, basic hand winch with modification of 1/4
HP Dodge electric motor with right angles gear reducer 11:1 ratio,
total 70 Ibs weight.
15. Downhole pulleys, guide wheels protects cables from damage on
inverts, extension pipes for varying depths of manholes.
16. Polaroid camera assembly, attaches on television monitor, clear
photographs of conditions discovered inside pipe lines.
17. Grout-sealing packer, rubber inflating bags seal on each side
of defect so full pressure of grout enters defect only, two separate
grout holes keep chemical from setting up in lines, acts as partial
plug so camera won't get emerged by water while sealing.
18. Chemical tanks, keeps chemical separate until point of injection,
80 psi, 30 gal capacity.
19. Water tank, 60 gal capacity, 100 psi, supplies snare water for
mixing chemical in field.
20. Air compressor, 180 psi, 4 HP gas powered motor, supplies con-
stant pressure for chemical tank, water tank and packer.
21. International Harvester Truck, 4-wheel drive.
58
-------
SUGGESTED INVENTORY FOR TELEVISION INSPECTION RIG
TOOLS
Solder Iron
Allen Wrenches
Needle Nose Pliers
Regular Pliers
Snips
Dykes
Knife
Volt Ohmraeter
Set Wrenches 3/16" - 1"
Crescent Wrenches
Screwdriver Set
Electric Drill
Drills 1/16" - 1/2"
Hand Vice Portable
Hammer
Hack Saw and Blades
Vice Grips
Channel Lock
Stripping Tool
Flashlight
Mirrors
Socket Wrenches
100 feet electric cord
25 feet electric cord
Steel Wool
Electrical Tape Rolls
Filament Tape
Fuses (one of each size)
Rag Bag
Hand Cleaner
Shrink Film Length
Grip Fittings
Polaroid Film Rolls
Miscellaneous nuts and bolts
Hex Head Screws
Swivels and Hooks
18 gauge wire roll
Spark Plugs, Generator
Gas Can
Water Jug
Stainless Steel Cable Splices
Oil
Dow Corning Silicon Grease
5-pin Y Connector (2)
5-pin Female Connector (1)
Two Cables with Snap Hooks
Grease Gun
Oil Can
File
Pipe Wrenches
Fire Plug Wrench
Fire Hose
Coal Chisel
Hand Pump and Hose
Manhole Hook
Crowbar
Shovel
Trash Can
SAFETY
Gas Indicator
Manhole Harness
Reflector Vents
Cones
Night Lights
Wet Suit
First Aid Kit
SUPPLIES
420 Watt Light Bulb (2)
625 Watt Light Bulb (2)
Solder Roll
59
-------
APPENDIX G
EQUIPMENT RECOMMENDATIONS
After our experience with sealing and televising there are certain
changes that we would make in our particular setup. The following
are suggestions that would enhance the ease and efficiency of the
operation.
All sealing and televising equipment should be mounted in an enclosed
truck. The truck should be equipped with four wheel drive if there
is any possibility of off-the-road sealing and inspection. The truck
should include special mounting for all accessory equipment such as
winches, hoses, shoes and tools. Mounting should be designed with
security of transport, neat, organized storage and accessibility in
mind.
There should be a special compartment for transportation of chemicals,
designed with their isolation from other equipment and puncture
damage in mind.
Provisions for mixing chemicals while the operation is in progress
are necessary. There are many possibilities, several of which are
listed here.
Separate mixing tanks and transfer pumps mounted on pickup truck.
Separate mixing tanks and transfer pumps mounted in sealing van.
Two sets of shooting tanks with appropriate valving so one can be
open for mixing while the other is in use. This can be made cheaper
by substituting a positive displacement shooting pump for pressurized
tanks and using fibreglass or lighter gauge metal tanks. Tanks must
still have a tight cover to prevent spillage in transit.
A mobile water tank, preferably mounted in the pickup truck should
be available in case the auxiliary water tank in the shooting rig is
exhausted before the rig can pull out of a span.
A power driven winch is a necessity, with remote controls at the
operators station by the TV monitor and the sealing controls. See
Figure 18 for the solutions to the power winch problem that we arrived
at.
It is worthwhile for an operation that is continuous to have a standby
camera. We lost an average of three days of work every time the camera
went out.
A device for cutting out extreme protruding laterals that will not permit
the packer to pass through the line would be extremely useful.
60
-------
POWER WINCH
CABLE REEL
with 5OO' cable truck mounted
TRAILER PANEL MOUNT
Dodge 25A
SC.R. Cabinet
control with variabta
speed, variable tor-
que, stop, start, 8
reversing action
Volt 60 Cycle
Trailer Supply
CABLE WINCH
Furnished by CUES Inc.
1/4" Stainless Sttel coble
I Reduction
Motor feild
twist lock plug
Boston No. FCBB 15
Jaw lypt coupling
with Elastomer Insert
Dodge WMI2AK
1 Right angle reducer
coupled to IN
winch reduction
Motor orm-
ature twist
1/4 h.p. Dodge
S.C.R. drive motor
Fig. 18
61
-------
APPENDIX H
SPECIAL DETAILS OF SEALING OPERATION
During the sealing operations we gained a good deal of practical exper-
ience regarding the general operation and actual sealing itself. The
following information is valuable to someone starting out.
Spans cannot be sealed uphill against the flow for the following
reasons: when the packer is inflated it forms a partial plug in the
line; if the camera is upstream of the packer it becomes submerged
and visibility is gone. When sealing upstream the excess gel down-
stream (especially in a line with a fairly flat grade) causes the flow
to back up and partially submerge the camera lens.
When we encountered obstructions in the line that would not pass the
packer we would seal up to that point, pull back, hook all the hoses
and cables together, pull them to the downstream manhole, hook on the
camera and the packer, back them up the line to the obstruction and
resume sealing. This way we avoided moving the trailer and sealing
upstream.
The packer must be washed and its holes cleaned every time it is taken
out of a span.
When sealing keep the flow rate of both the chemicals identical to
avoid backflow and sealing up the holes in the packer. Never turn
on one sealant without the other. Start sealing at a fixed flow
(we used 2 gpm), and watch the pressure gauges. When the pressure
begins to rise .above normal steady flow shut off the flow. With
experience one can do this before overspray occurs. If both gauges
hold more than 2-3 psi the joint is sealed.
If a joint will not seal there are several techniques that can be used:
1. Slowing the flow to give the gel longer to take effect.
2. Shutting off completely and giving the existing chemical time to
set up. We always ran a minimum of 60 seconds before trying this.
3. Momentarily increasing the Q-Seal A (catalyst) flow rate will
speed gel time sometimes and seal-a joint faster. This is especially
valuable when the sealer is getting away too rapidly through porous
soil. Be careful to avoid backflow in the packer when doing this.
After a joint is sealed the packer should remain inflated for the
gel time. This prevents a buildup of sealant between camera and packer
and buildup downstream which will eventually pile up between the camera
and the packer as they are moved down the line. This can be ignored
at times of very high flow in steep grades.
62
-------
If one man operates the sealing panel and the other keeps the logbook
and operates the power winch the efficiency of the operation can be
maximized.
A gel time of 10 to 12 seconds was used exclusively. Any longer just
extends the length of time one must be set up on a joint after sealing.
Alignment of the packer on a joint is accomplished by triangulations
with the camera and the top edge of the packer. The length of the
tow cables between the two is such that the relationship shown in
Figure 19 exists.
-------
METHOD OF SETTING PACKER ON JOINT BY
TRIANGULATION
Pocker Skids
acker Inflated In Position
Air Line From Sealing Unit
T.V. Coble To Monitor
In Inspection Unit
Camera Light
T.V. Camera
Two Chemical Lines
From Sealing Unit
Tov Coble re Inspection Unit \Mnch
T.V. Cable Guard Skid
\—Tow Cable To
Sealing Unit Winch
Sight Of Camera
Joint
.Packer Skids
Packer
T.V. Camera Skid*
Ruptured Sewor Line Bell
T.V. Camera Guard
Skids
ATM Of Stabalized Soil
After Leak Repair
T.V. Camera
-------
APPENDIX I
METHODS OF DETERMINING THE NEED FOR SEALING
Television inspection, except in areas of constantly high water
table is not conclusive for determining the need for sealing. The
following is a summary of the visual and actual joint conditions
and their correspondence.
Visually good (perfectly concentric): 782 joints 100%
Actually good (0-.9;gal seal): 583 joints 74%
Actually medium (.9-1.9 gal seal): 138 joints 18%
Actually bad (2.0 gal seal 5 up): 61 joints 8%
Visually medium (0-1/2" offset): 539 joints 100%
Actually good (0.9 gal seal): 380 joints 70%
Actually medium (.9-1.9 gal seal): 89 joints 16%
Actually bad (2.0 gal seal 5 up): 70 joints 14%
Visually bad (1/2" offset 5 up): 273 joints 100%
Actually good (.9 gal seal): 145 joints 53%
Actually medium (.9-1.9 gal seal): 63 joints 23%
Actually bad (2.0 gal seal 5 up): 65 joints 24%
This shows fairly conclusively that purely visual inspection, when
the pipe is not immersed in ground water, is inconclusive for deter-
mining the need for repair by sealing.
65
-------
APPENDIX J
DESCRIPTION OF GROUT
A. Chemical Composition
Q-Seal D
a. Acrylamide and NN1 - methyienebisacrylamide
white powder (MBA)
b. Beta-dimethylaminopropionitride
clear liquid (DMAPN)
Q-Seal A
a. Amonium persulfate
white powder
B. Mixing Technique
The ammonium persulfate was mixed with 30 gallons of water and
approximately 6 Ibs of ammonium persulfate was used.
The NNr methyienebisacrylamide (MBA) was also mixed with the DMAPN
in 30 gallons of water. Approximately 20 Ibs of MBA and 1 gallon of
DMAPN were used.
C. Injection
The chemicals foima stiff gel within 5 to 7 seconds after mixing.
The gel is stable in non-dehydrating surroundings, and was also found
to be extremely toxic and is designed only for use in sewers.
The grout also contains a weed killer. The composition is a trade
secret.
A possible method of determining the probability of a need for seal-
ing in an area is to make test borings to analyze trench conditions.
Figure 3 shows soil conditions and non-functional ground water pipe
locations (low soil permeability) correlated with the condition of the
lines (amount of sealant used per foot of line). The general indica-
tion is that in areas where the permeability is low in the trench,
the lines are self sealing, even if they may have defective joints.
Judiciously placed soil borings could be used as one of the indicators
in determining the need for joint sealing in an area. In areas with
high permeable backfill material every defective joint is bound to
leak under high ground water conditions.
A basic survey of an area to decide the need for sealing should include
the following criteria:
66
-------
Determination of existence of high flow problems.
Determination of trench conditions, either by borings or by knowledge
of construction procedures. (The latter is not very reliable in old
systems.)
Determination of the existence of non-prwiium joints.
Determination of the existence of ground water in the area, either
constant or responsive to rainfall.
Observation of the methods of foundation and roof drainage. If it is
possible that these cause high flow problems then all possible means
should be exhausted for removal of these problems before sealing.
Smoke testing may be some help in these locations.
Removal of other possible sources of gtomwater connections to sanitary
before dealing.
67
-------
APPENDIX K
TABLE I
GIOUND WATER INDEX
Date
3/5/70
3/9/70
3/23/70
3/31/70
4/2/70
4/3/70
4/8/70
4/10/70
4/14/70
4/16/70
4/23/70
4/24/70
4/29/70
5/1/70
5/5/70
5/8/70
5/12/70
5/14/70
5/18/70
5/22/70
5/26/70
6/3/70
6/9/70
6/16/70
6/22/70
6/24/70
6/25/70
7/8/70
7/9/70
7/23/70
11/10/70
11/17/70
12/7/70
12/22/70
1/8/71
1/14/71
2/3/71
2/5/71
2/18/71
2/22/71
2/26/71
3/9/71
3/11/71
3/15/71
3/22/71
Avg. Total $ Line
Underwater
72
79
76
78
100
100
92
92
87
100
71
92
75
77
72
71
73
67
67
70
69
58
61
74
70
59
69
63
44
64
45
46
73
66
40
32
22
63
46
65
80
86
83
100
91
Rain
Inches
1.64
.00
.00
.00
.19
.00
.00
.00
.00
.00
• 47
1.57
.00
.00
.00
.00
.88
.00
.00
.00
.00
.20
.00
.00
.00
.05
.00
.65
.10
.00
.02
.00
.00
.60
.00
.02
.00
.00
.00
1.50
.27
.00
.00
.55
.05
Intensity
(Inches/hour)
.07
.00
.00
.00
.09
.00
.00
.00
.00
.00
.13
.28
.00
.00
.00
.00
.27
.00
.00
.00
.00
.07
.00
.00
.00
.20
.00
.37
.05
.00
.26
.00
.00
.11
.00
.13
.00
.00
.00
.31
.03
.00
.00
.33
Snowmelt
-------
GROUND WATER INDEX
Date Avg. Total % Line Rain Intensity
Underwater Inches (Inches/hour)
4/2/71 92 .00 .00
4/13/71 6.9 .00 .00
4/15/71 50 .00 .00
4/19/71 39 .00 .00
4/23/71 70 .00 .00
4/27/71 45 .73 -48
4/28/71 50 .00 .00
5/3/71 53 .00 .00
5/6/71 69 1.80 .37
5/10/71 97 .00 .00
5/12/71 96 .02 2.0
69
-------
ACKNOWLEDGEMENTS
The support of the County Commissioners of Montgomery County, Ohio,
Mr. Robert F. Kline, Mr. Thomas A. Cloud, and Mr. Charles M. Lewis,
and the Administrator of Montgomery County, Mr. Paul E. Stockert,
are acknowledged with sincere thanks.
Mr. C. W. DeHaven, Director, and Mr. Cene E. Cronk, Sanitary Engineer,
are thanked for their guidance and assistance in the preparation of
this report.
Mr. Shepherd Goodspeed, Mr. Paul Feinstein, and Mr. John R. Patterson
are acknowledged for their work during their employment at the Mont-
gomery County Sanitary Department.
Mr. John Mossbarger's activities as foreman of the televising, sealing,
and labor crews, is appreciated.
The' support of the project by the Water Quality Office, Environmental
Protection Agency, and the help provided by Mr. Eugene F. Harris,
Project Officer, is acknowledged.
71
-------
1
Accession Number
w
5
A I Subject Field & Croup
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
Montgomery County Sanitary Department
Title
GROUND WATER INFILTRATION AND INTERNAL SEALING
OF SANITARY SEWERS, Montgomery County, Ohio
10
Authors)
Gene E. Cronk
John R. Patterson
Paul Feinstein
Shepherd Goodspeed
16
Project Designation
EPA Grant 11020 DHQ
Note
22]
Citation
23
Descriptors (Starred First)
•"•Infiltration, Wastes, Sealants, *Sewers
25
Identifiers (Starred First)
^Montgomery County, Ohio, "Television Inspection
27
Abstract
A program for pollution abatement was undertaken by the Montgomery County
Sanitary Engineering Denartment in Southwest Ohio to research the effects
of infiltration reduction by joint sealing and to study closed circuit
television techniques.
Water Pollution from municipal wastewater treatment plants would be reduced
if peak flows from rainfall could be reduced. This study evaluates the
effects of remedial repairs to joints by use of pressure grouting of small
main line sewers. A minimal measurable amount of quantity flow reduction
was attributed to the sewer sealing program. This is to say that infil-
tration from extraneous storm water, illegal connections, and basement
underdrains seem to outweigh the contribution due to leaky joints to such
a degree that reduction due to joint sealing was obscured.
The study does show the significance of internal television system as an
inspection and maintenance tool. This information on costs, operation,
and procedure is of value to anyone interested in this field.
A bstractor
Gene E. Cronk
Institution
Montgomery County Sanitary Department
WR:I02 (REV. JULY
WRSIC
ft U.S. GOVERNMENT PRINTING OFFICE: 1 972 — It
SEND, WITH COPY OF DOCUMENT. TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINCT ON. D. C. 20240
GPO: 1970 - 407 -881
? (3"l9)
-------
|