sewerage maintenance
TRANSCRIPT
Basics of the Sewer
Maintenance
Mr. Toshio Kitou
Ms. Megumi Sakino
Sewer Maintenance Section,
Facilities Management and Maintenance Division
Bureau of Sewerage
Kanda
Sewer
Year 1884
Areas of improved sewer systems by the year of improvement
Sewers improved by 1945 for the most part (first reconstruction area)
Sewers improved by 1970 for the most part
Sewers improved by 1983 for the most part
Sewers improved by 1994
13% 1%8%
27%24%
27%
FY1945 former
FY1946 to FY1955
FY1956 to FY1965
FY1966 to FY1975
FY1976 to FY1985
FY1986 to the current
Comparison of the total pipe length by the year
Currently, the total length of
pipes that are constructed
more than 50 years ago is
1,500 km, which accounts for
about 10% of the whole length.
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
0
100
200
300
400
500
600
Bef
ore
193
9
1944
1949
1954
1959
1964
1969
1974
1979
1984
1989
1994
1999
2004
2009
2014
2019
2024
2029
2034
2039
2044
2049
Sum
tota
l le
ngth
of
pipe
s
（lin
e gr
aph:
km）
Tota
l pip
e le
ngth
in
a si
ngl
e fisc
al y
ear
(bar
gra
ph : k
m)
Fiscal Year
Total pipe length in a single year Total aged pipe length in a single year
Sum total length of constructed pipes Sum total length of aged pipes
Total maintained pipe length by the year and increase in aged pipes in the future
Flow chart for pipe maintenancePipe maintenance
Ledger maintenance Daily maintenance
Inspection, checking, report
Inside pipe examination
Emergency measures Systematic measures (preventive maintenance)
Pipe cleaning
Repairing (mending)
Troubleshooting
Systematic pipe cleaning
Systematic repair (mending)
Systematic improvement
(rebuilding)
Reconstruction
Inspection of pipe system
Joint inspection at the construction site
with other companies
Inside pipe cleaning
Large diameter pipe conducted by human
power
Small diameter pipe conducted by a
water-jetting sewer
cleaner
Inverted siphon pipe conducted by TM
submerged scratcher
Cleaning of large diameter pipe (human power)
Cleaning of small diameter pipe (water-jetting sewer cleaner)
Water-jetting sewer cleaner
Cleaning of inverted siphon pipe
Bucket
→
Total length of cleaned pipes and the total length of maintained pipes
0
200
400
600
800
1,000
1,200
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
Total length of pipes maintained Total length of pipes cleaned(Km) (Km)
Inside pipe inspection
Visual check
TV camera Check
For main pipes
For lateral pipes
Total length of pipes inspected inside
0
2,000
4,000
6,000
8,000
10,000
12,000
0
200
400
600
800
1,000
1,200
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
Total length of pipes inspected inside Sum total （Ｋｍ）（Ｋｍ）
Inside pipe inspection (visual check)
Inside pipe inspection (TV camera check)
TV調査
When a pipe becomes old,
it shows damages.
In order to keep the sewer
in a good condition,
workers are checking
inside of the pipe.
Inside of a
pipe is
diagnosed by
inserting a
camera like
this one into
the pipe from a
manhole.
Inside pipe inspection (TV camera, main
pipe)
A TV camera lowering
into the pipe from a manhole
A TV camera showing ｜inside
of a pipe.
A TV camera is operated
from the ground.
The pipe
has a
crack.
The pipe is
broken
and
damaged.
カメラでの撮影結果１
カメラでの撮影結果２The joint of
the pipes is
out of
alignment.
The pipe is
eroded and
the steel
inside the
pipe is
exposed.
カメラでの撮影結果３
The pipe is
clogged
with
mortar.
The number of roads sagged and the cost for rework
0
500
1,000
1,500
2,000
2,500
3,000
0
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
1983
1986
1989
1992
1995
1998
2001
2004
2007
General rework cost Maintenance cost The number of roads sagged(Number of work cases)(10,000 yen)
What is the pipe diagnosis system?
1. It manages data that provide information about
results of inside pipe inspections, sagging
roads, and records of floods, which is
necessary to the maintenance of sewer
facilities.
2. It determines a type of construction to repair
damaged pipes and decides which
construction work should have priority.
☆The system contributes to the preventive maintenance.
Information on sagging roads
Information on inside pipe inspection Information on
construction work
Information
on flood
Information on
sewer system
Report on pipes that need
improvement/repair
Database file (CD-ROM)
Information users
Pipe diagnosis systemSewerage
Mapping and Information
System (SEMIS)
The pipe
diagnosis
system keeps
various kinds
of information.
Chart for parts requiring
improvement/repair
Pipe diagnosis system in perspective
Each sewer pipe
is inspected and
damage
information is
computerized for
database entry.
Display screen of inside pipe damages
要対策の判定Type of damage Rank A some damages Rank A extensive damages
Obsolescence
Deterioration
Indication
Damage
Breakage
Measures for improvement and repair are necessary.
Crack
Misaligned joint
Erosion
Water leakage
Sagging, meandering
Measures for repair are necessary.
Mortar adhesion
Extrusion of lateral pipe
Lard adhesion, root intrusion
Other
Assessment of the necessity of measures
Improvement cost
Repair cost
Y years50 years
Y+50 years
Construction cost
Gradient line of cost in the
year pipe was improved
Gradient line of cost
in the year pipe was
repaired
Comparison of costs for improvement and repair
for a pipe that will need such work Y years after its construction
Assessment of the necessity of measures
Priority of reconstruction work is determined and a color-coded work chart is created.
Color-coded chart of pipes requiring
improvement/repair work
Example
First priority for
improvement work
Second priority for
improvement work
Third priority for
improvement work
Repair is necessary
No measures are
required.
Based on information
about obsolescence
and damage of pipes,
priority of
reconstruction work
is determined.
ＳＰＲ
Preparation for work
New pipe
A new pipe is being constructed
inside of the existing pipe
Existing pipe is
internally
coated in order
to construct a
new pipe