SEWERAGE SYSTEM
Sewerage system consists of pipes,pumps for collection of wastewater, or sewage, from a community. Modern sewerage systems fall under two categories: domestic and industrial sewers and storm sewers.
TYPES OF SEWERAGE SYSTEM
COMBINED SEWERAGE SYSTEM:
A combined sewer system is a sewer that accepts storm water, sanitary water/sewage, then the sewage is treated in STP(sewerage treatment plant). This system is mainly used in the towns where streets are narrow and rain fall is less than the moderate.
ADVANTAGES:
a) less construction cost
b) There will be No chocking problem
c) strength of the toxic water will be reduced.
DISADVANTAGES:
a) Due to sewage the toxicity of storm water will increase.
b) Initial cost of piping will be high.
c) Problem in handling.
SEPARATE SEWERAGE SYSTEM:
In this system the sanitary sewage and storm water are carried separately in two sets of sewers. The sewage is conveyed to waste water treatment plant (WWTP) and the storm water is discharges into rivers without treatment.
ADVANTAGES:
a) The rain water will not become toxic.
b) More efficient than combined system.
DISADVANTAGES:
a) Problem of chocking.
b) Flushing system will be required for cleaning purpose.
PARTIALLY COMBINED OR PARTIALLY SEPARATE SYSTEM:
A partially separate system is a combination of a combined sewerage system and separate sewerage systems. This type of sewerage system helps decrease the load from a combined sewerage system because only the water from initial rain falls(water from acid rain) is added to sewage water and after than this system work as separate system.
ADVANTAGES:
a) The sizes of sewers are not very large as some portion of storm water is carried through open drains.
b)Combines the advantages of both the previous systems. Silting problem is completely eliminated.
c) storm water will be less toxic as compare to previous two systems.
DISADVANTAGES:
a) The storm water is unnecessary put load on to the treatment plants to extend.
b) The toxicity of sewage water will increase.
