flow contribution from a school 1

[kchayfie]

We have been asked by our client (a local water authority) to assess their risk regarding a new development proposed for construction over the next 30 to 40 years. Needless to say, the developers plans are a little vague at the moment and so we are struggling to build a picture of the likely additional wastewater flows arising from the development.

We've been able to put flow figures to most contributing land areas but I have nothing for schools. The developer has provided a proposed area dedicated to "education" but I haven't been able to translate this into a number of pupils or a waste water flow figure.

Does anyone have rule-of-thumb to guide me? Something along the lines of "a school of x pupils will require a land area of y cubic meters" would be great.

Thanks

 

[Ussuri]

Could you do a survey of schools in your area to calculate the plan area and the number of pupils it contains per floor say?

You could get reasonably accurate building plan sizes from a GIS system or a CAD based map (Ordnance Survey in the UK).

This might give you an ide of what size school you could conceivably get on your site.

 

[LHA]

I think you are working this backwards. Don't guess how many students and floors might be built; the Authority should require how much water and sanitary sewer flow the developer wants to reserve, prior to commenting on a plan's feasability/risk. The fire flow calcs must be run by their licensed professional consultant. The sanitary calculation is also usually run by their licensed professional consultant, although I don't think it has to be.

Then make the developer tell you the area, ht and occupacy of the bldg(s) they used to calculate fire flow/water; and how many housing units they used to calculate wastewater flow. Assume a conservative figure...maybe 3 kids per household, and one staff member per 20 kids, in USA. Then, back-checking their calculations will be straight-forward.

Engineering is the practice of the art of science - Steve

 

[bimr]

I assume that you are asking for how much wastewater is discharged from a school.

You would have to look at the planned land use. The developer should be able to give you the number of homes. From the number of homes, you should be able to estimate the number of school children.

Once you have the estimated number of children, you can estimate the flow.

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

Another way to look at it to estimate the school size. (You have not said what type of school, elementary, middle, or high school that you are considering.)

http://nces.ed.gov/programs/quarterly/vol_5/5_2/q3_5_t1.asp#Table-5

Table 5. Average public school size (mean number of students per school), by instructional level and by state: School year 2001–02



This chart shows that average school size by state. So if you are in North Carolina, the average elementary school size is 489 students or 489 * 25 gpd/per student or 12,225 gpd.