In general, domestic wastewater entering municipal wastewater systems tend to follow a diurnal
pattern (Asano et al. 1985). This flow is low during the early morning hours and a first peak
generally occurs in the late morning followed by a second peak in the evening—after dinner hour.
However, the ratio of peak flow loads to average flow is likely to vary inversely with the size of
the community and the length of sewer system. Peak flows may also be generated during festive
occasions, and at times of religious rituals, such as the Friday prayer in Pakistan, during business
hours, tourist seasons, and in areas with large university campuses etc.