150 FROM
ABOVE
50 VENT
150 AT HIGH
LEVEL ON WALL
5000L
5000L
TANK 1
TANK 2
150 TO STREET
SEWER
ELEVATION
SCHEMATIC
ONLY ONE TANK SHOWN FOR CLARITY
NOTES
Retention Capacity:
Nominal occupancy of building levels 1 to 5
171
MOTORISED VALVE
Design water use
158 litres per person per day
Water use per day
27,000 litres
50 VENT
150 AT HIGH
Assume approximately one third retention morning and night at peak times.
LOW LEVEL ENTRY/DRAIN POINT
LEVEL ON WALL
Storage required 9000 litres. Install two 5000 litre tanks.
HIGH LEVEL DRAIN
Operation:
POINT INSIDE TANK
5000L
5000L
Close motorised valve from 6.00 am to 10.00 am and 5.30 pm to 9.30 pm.
150 DROPS TO BURIED DRAIN
Valve 25% open 10.00 am to noon and 9.30 pm to 11.30 pm (to drain tanks).
Valve fully open noon to 5.30 pm and 1130 pm to 6.00 am.
150 TO STREET
PLAN
SEWER
LEGEND
PERMANENT
SHORT-TERM
INSTALL LATER
THE WELLINGTON COMPANY
Hydraulic Services
Date
MTA House
3 June 2016
Waste water retention tanks
Scale
N. T. S.
3882
P1
A
79 Taranaki Street , Wellington
WALKER ARCHITECTURE & DESIGN 
Original Size A3
Project No.
Drawing No.
Revision

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