Quantifying the amount of Wastewater for a Office Building 1

[SJcivil]

I need to design a small lift station for an office building, is there a resource to help me quantify the design flow for wastewater produced by that building.

Thanks
SJCivil

 

[sammyk]

Here are the factors I use for office buildings:
25 GPD/employee (minimum)
or
0.10 gal/sq.ft. (usable & heated space)
or
1 P.E. = 100 GPD

 

[RWF7437]

OR............
You can collect water use data from nearby, similar offices and develop your own design criteria.

good luck

 

[bimr]

You can use the data in Metcalf & Eddy; or lacking that, here is an online reference:

http://www.ilga.gov/commission/jcar/admincode/035/03500370ZZ9996bR.html

Offices, schools and business establishments

15 Gallons Per Person Per Day per shift

 

[sammyk]

Be careful when using a "per person/day" calculation in non-residential applications. Usage "can" change over time and a lower initial rate can cause problems down the road.
Theres a huge difference in the differing types of offices
(ie call center versus your office).

Ive run into a situation where the sanitary district was being a pain and decided my "new" usage (on old office building) required extensive downstream sanitary upgrades and fees. The client (which was the original owner as well) was not happy.

 

[jartgo]

This design flow is likely determined by your state's department of environment or whatever it may be called where you're working. As bimr and sammyk pointed out it's usually about 25 gpd/per employee, but again the state will likely tell you what to use. The idea of obtaining flow data from a similar development will give the best results and allow for maximum efficiency in the design, but the local regulators where I work require a year of flow data to even consider anything other than the published flows...as such, very rarely do I go that route.

What I always find to be interesting is how folks split that daily flow into gpm for conveyance design. That is, say it's 25 gpd/per employee, but is that employee going to dump (pardon the expression) it all into the system in 8 hours, 12 hours, 24 hours? It can make a difference.