Peak wastewater flow from dormitory?

Question

Are there standards for estimating the peak instantaneous wastewater flow from a large dormitory. I have info such as the number of toilets and the number of shower heads, and I am inclined to think that peak flow would be with about 90% of the toilets and shower heads operating simultaneously, but that yields a very large number for peak flow.

Answer 1

Consult your state environmental dept. They usually have standards for the design of sanitary sewers and the literature is usually free. The local health dept. might have that data, for use in designing septic systems. If you are doing for an actual design, then you need to use the state or local standards.

If it is for homework, the bible in this area is Metcalf & Eddy's text.

Answer 2

Good question. The plumbing has to handle the peak, not the average. If all the toilets flush at once and the system doesn't handle the peak -- well, you can see the difficulty. Further, it is actually often that most of the toilets will flush within a 2 to 4 minute period, synchronized with the local time. Doubt that? Watch the municipal water pressure during the commercials of an NFL game. NYC discovered it years ago. It is called "the TV Flush". For a college dorm, class schedules and date preparation should produce the peaks.

Answer 3

That is probably not true. Here is a simple logical way to work.

In a shower; estimate the time when shower is on - when a person is occupying the shower .... approx - 60% of the time.

Similarly in a toilet, it may be 5% or lower. This can help u estimate