Correct Answer - Option 1 : Lead sewer
Explanation:
Lead Sewers:
(i) They are smooth, soft and can take odd shapes.
(ii) This pipe has an ability to resist sulphide corrosion.
(iii) However, these pipes are very costly.
(iv) These are used in house connection.
Brick Sewers:
(i) Brick sewers are generally made at site. They are used for construction of large size sewers or particularly for storm water drains.
(ii) The pipes are plastered from outside to avoid entry of tree roots and ground water through brick joints. These are lined from inside with stone ware or ceramic block to make them smooth and hydraulically efficient. Lining also make the pipe resistant to corrosion.
(iii) If brick sewers are to be used on a large scale, the purpose made bricks should be used instead of ordinary bricks. The advantage of brick sewers is that these could be constructed to any required shape and size.
Cast Iron sewer:
(i) Cast iron pipes may be used in the form of sewers, where they have to withstand high internal pressures and external loads. However, these are costly.
(ii) Cast iron pipes are used for outfall sewers, rising mains of pumping stations, and inverted siphons, where pipes are running under pressure.
(iii) These are also suitable for sewers under heavy traffic load, such as sewers below railways and highways. Light cast iron pipes are used for house drainage works, whereas, heavy ones are adopted for city sewers.
RCC sewer:
Advantages:
(i) Economical for medium and large sizes.
(ii) It is possible to effect saving in the cost of jointing, owing to the longer lengths in which these pipes are generally available.
(iii) They can be made of any desired strength.
(iv) Strong in tension as well as compression.
(v) These pipes are available in wide range of size and the trench can be opened and backfilled rapidly during maintenance of sewers.
Disadvantages:
(i) These pipes can get corroded and pitted by the action of H2SO4.
(ii) The carrying capacity of the pipe reduces with time because of corrosion.
(iii) The pipes are susceptible to erosion by sewage containing silt and grit.
