Water New Zealand Web Forum

[CluthaDC]

Are there standard formulae or guidelines for assessing the equivalent domestic sewerage rating units for Schools and such institutions? cheers
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Hank Stocker
Water Services Manager
Clutha District Council

[Graemem]

Hi Hank. I believe that the Auckland Regional Council did some work in this area and may have some information to assist. Try them.

[Dylan Stuijt]

I stumbled across a US guideline which I've converted from Gallons to Litres, which covers quite a few different operations, one being schools.

The guideline gives figures of:
Day School (no boarding) 38 ltr/student/day
Boarding School 379 ltr/student/day (includes cafeteria)

These can then be compared to what you deem to be a standard household equivelent.

If the you have some existing schools, you could data log their meter and use the standard 80% rule as being their wastewater flow (as long as they're not irrigating during that period), and work backwards based on their student numbers.

We're about to embark on this exercise ourselves, but to base the flow on typical floor areas. This would enable us to charge Development Contributions for every building addition to a school. In terms of the ministry of education, the permitted student numbers are based on the floor areas available. Many schools need to increase their floor area before applying to increase their role cap, therefore you need to capture any capital charges at the building consent stage. Be aware that you need to have provisions in the by-law to be able to charge schools development contributions. I.e. They become service provision fee's.
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Water Supply Manager - Hastings District Council

[HuntRP]

Environment Bay of Plenty uses the following wastewater flow allowances for schools:

Schools (pupils plus staff) 30 litres/ person / day - on-site roof water tank supply. 40 litres/ person / day - reticulated community or bore water supply.

I suggest that you also contact the wastewater consents staff at Environment Waikato and ask for their table of wasewater flow allowances.

[HuntRP]

TP 58 (Second edition, 1994), As/NZS 1547:2000; on-site NewZ 99/1 (January 1999) provides the following advice note:

Based on experience in the Auckland area actual recorded flows are around 15 litres/person/day on rainwater tank supply and 20 litres/person/day on community or borewater supply.

Richard Hunt
Civil Engineer
Sigma
Rotorua