This document discusses procedures and safety measures for sewer maintenance. It covers causes of sewer troubles like clogging, breakage, and odors. Methods of sewer cleaning like flushing, tools, and inspection are described. Requirements for maintenance like staff, equipment, and tools are outlined. Functions and selection of maintenance equipment and tools are covered. Hazards like explosions in sewers and safety precautions are also summarized.

1. MAINTENANC
E OF SEWER
SUB : WS&SE
BY : D.D.DATTANI
CHAPTER-11

2. INDEX
 PROCEDURE OF SEWAGE SYSTEM
 CAUSES OF TROUBLE & ODOUR
 SEWER CLEANING OPERATIONS
 REQUIREMENT FOR MAINTENANCE
OF SEWER
 FUNCTIONS OF MAINTENANCE
EQUIPMENT & TOOL
 SELECTION OF EQUIPMENT
 EXPLOSIONS IN SEWER
 SAFTEY MEASURES OF SEWER MEN
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3.  Repair Of Manholes
 Construction Of Manholes
 Replacing Stolen Manhole Covers
 Raising Height Of Manholes With Road Levels
 Repair Sewer Lines
 Cleaning Of Sewers
 Prevention Of Clogging
 Checking Of Leakage & Repairs
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PROCEDURE OF SEWAGE SYSTEM

4.  Periodical inspection sewer
 Measurement of flow rate
 Cleaning of sewer
 To carryout flushing of sewer to prevent clogging
 Repair of pipelines
 To prepare schedule for maintenance
 To supervise the work of repair and maintenance
 To prepare estimates of maintenance of report
 To prepare m & r proposals and take approval of higher authority
DUTIES OF MAINTENANCE INCHARGE
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5.  Clogging of flow
 Breakage of sewers
 Odour formation
CAUSES OF TROUBLES AND ODOUR
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6.  The following factors are responsible for clogging of flow :
 Deposition of grit and sand particles.
 Accumulation of suspended matter in the sewage
 Deposition of grease and oily matter
 Penetration of tree roots in the sewer.
 Deposition of tarry material assisting in binding the detritus.
 Falling of dust and dirt in open man holes.
CAUSES OF TROUBLES AND ODOUR-
CLOGGING OF FLOW
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7.  The following factors are responsible for Breakage of sewers
 Poor workmanship and poor quality of materials
 Faulty design
 Excessive superimposed load
 Settlement due to loose foundation
 Explosion inside the sewer due to improper ventilation of the explosive gases inside the
sewer
 Undermining of sewer due to any reasons.
 Deterioration of sewer due to corrosive gases.
 Abrasion of sewers due to frictional movement of the solids present in the sewage
 Old age of the sewer.
CAUSES OF TROUBLES AND ODOUR-
BREKAGE OF SEWERS
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8.  The following factors are responsible for odour Formation:
 Breakage of water seal
 Leakage through sewers
 Evaporation of water from water seal
 Defective joints
 Clogging of vent pipe or shaft
CAUSES OF TROUBLES AND ODOUR-
ODOUR FORMATION
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9.  Methods of Cleaning & Maintenance :
 The most common methods adopted are:
 Cleaning and Flushing
 Cleaning of Catchpits
 Inspection
 Periodical repair
 Proper Connection
SEWER CLEANING OPERATION
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10. SEWER CLEANING OPERATION-
SEWER CLEANING TOOLS
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11.  In case of large sewers, cleaning is done manually.
 The man enters the sewers through manholes and scraps the sides of sewer by brushes.
 The scraped material is removed through man holes.
 In case of small sewers, cleaning is done by flushing.
 For this purpose, automatic flushing tanks are sometimes installed on the sewer line.
 A fire hose may be also inserted in the sewer and the water under pressure may be
discharged through the house to clean the sewer.
 When flushing is ineffective to remove the obstructions in the sewer, the following methods
may be adopted to clean the sewer.
SEWER CLEANING OPERATION
CLEANING AND FLUSHING
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12.  Flexible rod
 Mechanical tools
 Use of pills- wooden,rubber or hollow metal
SEWER CLEANING OPERATION
CLEANING AND FLUSHING
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13.  (I) FLEXIBLE ROD
 A flexible rod of about 30 m length is inserted into the sewer.
 It is then pushed forth back.
 The movement of rod dislocates the obstructions and it becomes easy to remove them
flushing.
 (II) MECHANICAL TOOLS :
 In this method, special cleaning tools are attached to the front portion of the rod and
cleaning of sewer is then carried out by moving the rod back and forth.
 The tools may double-worm screw, drain brush, wire brush, etc.
SEWER CLEANING OPERATION
CLEANING AND FLUSHING
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14. SEWER CLEANING OPERATION
CLEANING AND FLUSHING
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FLEXIBLE ROD MECHANICAL TOOLS

15.  (III) USE OF PILLS
 This is an interesting method of cleaning the sewer.
 In this method, small pills or balls made of wood or rubber or hollow metal covered with canvas are put in the
manhole above he obstruction.
 The pill floats in the sewage and when it comes near the obstruction, it is caught there and the sewage starts
collecting behind it.
 When sufficient head is developed, the accumulated sewage removes the obstruction and the pill is caught in the
next manhole.
 Then a pill of slightly larger diameter than the previous one is taken and the process is repeated untill a pill
having diameter about 25mm less than that of sewer passes easily from one to the other.
SEWER CLEANING OPERATION
CLEANING AND FLUSHING
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16. SEWER CLEANING
OPERATION
CLEANING OF CATCH PITS
 Used to collect rain water
 It contains mosquitoes,silt,sand etc
 It gives unpleasant odour
 The oil and grease traps are used for cleaning
and also to avoid nuisance of unpleasant odour
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17.  Before repair inspection is done
 Periodical inspection is necessary
 Sewer on flat grades= 3months
 Sewer troubled by roots =3 months
 Sewer with no trouble= 6-12months
 Inspecting sewers= 7-30days
 Flushing tanks=1month
 Inverted syphons= 7-30days
SEWER CLEANING OPERATION
INSPECTION
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18.  Manhole must be examined periodically
 The brick sewer required frequent repairs
 The broken brick shall be replaced
 The broken covers must be repaired
 The manhole cover which are loosen by traffic must be repair
 The ventilation must be check periodically
SEWER CLEANING OPERATION
PERIODICAL REPAIRS
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19.  Connection between house sewer and street sewer must be check
 The connection of lateral sewer and branch sewer must be repaired by licence plumber only.
SEWER CLEANING OPERATION
PROPER CONNECTION
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20.  The main requirement for maintenance of sewer :
1. Crew or staff of maintenance.
2. Equipment's for maintenance.
3. Tools for maintenance.
4. Trucks for transportation of material and staff.
5. Map of sewage system.
REQUIREMENT FOR MAINTENANCE OF
SEWER
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21.  For the maintenance of sewers, the following staff is required in sanitary department :
 Assistant Engineer/Additional Assistant Engineer
 Truck drivers
 Sewer-men for inspection of sewer
 Sweepers
 Labours
 Masons,etc
REQUIREMENT FOR MAINTENANCE OF
SEWER
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22. FUNCTIONS PF MAINTENANCE
EQUIPMENTS & TOOLS
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Sr.No Equipment Uses
1 Fire hose For flushing of sewers
2 Flexible wire To remove clogging
3 Flexible sewer rod It is dragged in sewer for removing
clogging
4 Interlocking wooden rod To remove clogging
5 Root cutter To cut tree roots entered in sewer
6 Sewer brush To remove oily matter
7 Flash light For inspection of sewer

23. FUNCTIONS PF MAINTENANCE
EQUIPMENTS & TOOLS
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SR.NO EQUIPMENT USES
8 Gas detector
To know the presence of gas formed in
the sewer
9 Flood light For inspection
10 Manhole guard rail To prevent falling of person in manhole
11 Traffic signals and red flag
for warning to vehicle and pedestrians
while work is in progress
12
Skull guard with electric
lamp
For warning to vehicles and pedestrian
13 First aid box For immediate treatment
14 Safety equipment kit For safety of labours
15 miscellaneous For ease in maintenance

24.  Gas masks
 Oxygen breathing apparatus
 Portable lighting equipments
 Portable air blower
 Saftey belts
 Inhalators
 Non-sparking tools
THE SAFETY EQUIPMENTS ARE
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25.  Gas masks
 Oxygen breathing apparatus
 Portable lighting equipment's
 Portable air blower
 Safety belts
 Inhalators
 Non-sparking tools
SELECTION OF EQUIPMENTS FOR GIVEN
MAINTENANCE JOB:
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26.  Select equipment for the type of work to be done
 Initial cost must be low
 It should be easy to oerate
 It should be easy to repair
 Allied equipment should be available
 It should have long life
SELECTION OF EQUIPMENTS FOR GIVEN
MAINTENANCE JOB:
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27.  The main sewer gases are :
 Naptha
 Methane gas
 Carbon-di-oxide
 Hydrogen sulphide
 Hydrogen
 Ammonia…etc
EXPLOSION IN SEWER
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28.  The following precautions should be taken to prevent the explosions in sewers
 Workman before entering in the manhole first lower a burning candle inside the manhole to check presence of
explosive gases
 Only dry cell torches or electric lamps should be used inside the sewer line for light purpose.
 The presence of hydrogen sulphide gas is detected by lowering a wet lead acetate paper inside the manhole.
EXPLOSION IN SEWER
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29.  Emergency first aid kit should be provided to take care of all minor injuries, cuts and burns to the gang
 In case of emergency the services of a doctor should be available
 No smoking or open flumes should be allowed.
 Naphtha
 Methane gas
 Carbon dioxide
 hydrogen sulphide
 All the concerned workers should educated about the hazards of water borne diseases
 Rubber gloves should be used so that sewage may not come in direct contact hands.
 Workers should use gum-boots.
 Workers should wash hand with soap and hot water before taking food.
 Gas masks and oxygen breathing apparatus should be made available.
 Only permissible safety lights, rubber or non-sparking shoes and non-sparking tools should be used.
SAFTEY MEASURES FOR SEWERMEN
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