This chapter deals with the hydraulic calculations of sewers and sewage disposal stations based upon design criteria developed in chapter # 3. The location, size, name and direction of flow of all sewers and pumps are designated. There are three disposal points for discharging the sewage of University campus. According to this we divide the whole area of the University into 3 units. We studied the flow of sewage being contributed to each disposal station and see whether the trunk sewers, which join the disposal station, are adequate, under sized, or over sized.

For hydraulic consideration we took average water consumption 100 gpcd (0.3785m³/d) in average Lahore residential communities. Wastewater works collect the spent water of the community about 75% of the average daily consumption, together with the varying amounts of entering ground and surface water. So we estimate flow (A.D.F).

For residence 75 gpcd (0.284 m³/d)

For hotels 40 gpcd (0.1514 m³/d)

For departments 10 gpcd (0.03785 m³/d)

For day-scholars 5 gpcd (0.0189 m³/d)

The University area is flat enough, so we used self-cleansing velocity 0.6 m/sec.

Normally sanitary sewers are designed as follows.

Design flow = peak flow + infiltration +storm allowance

Peaking Factor = 4

Peak flow =Peaking Factor x average daily flow

We took

Infiltration =100% average daily flow.

Storm allowance =peak flow

It is situated near Jamia mosque in the S-W direction at about 12-m. There are four main sewers joining this disposal station. These are designated as FF^/, GG^/, HH^/, and II^/ shown in the fig. 5.1.

The calculations for each trunk sewer were tabulated and finally the adequacy of pump, designated as P₁ in the fig. 5.1 was checked.

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