domestic discharge calculation

[akce]

My first commercial sewer system rehab project: WW system serves office, kitchen, showers.
In calculating design discharge, what approaches are typically taken for a small commercial systems?
1. estimate avg. flow per person per day?
2. based on # & type of fixtures at some nominal flow rate?
3. ???

(The existing pump station was designed for 15gpm avg/45gpm peak based on # of persons.) #'s have changed - I must update.

Thanks

 

[LHA]

"Commercial" must be more specifically defined. An office uses 10gpd/employee, but a factory uses 35 gpd/employee.

Type of plumbing fixture does not tell enough, without considering what type of uses that fixture is likely to see. That is where the Type of Establishment comes in.

Try here:

http://www.pacode.com/secure/data/025/chapter73/s73.17.html

These values are only valid in PA, USA. But they are good, conservative estimates to get started with.

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve