Attachment J - Sewage Treatment Assessment

Table 1: Summary of typical flows for similar developments from available guidance
            Guidance                  Development Type           Typical Flows      Estimated Centre Flows (existing
                                                                 (L/person/day)              + expansion)
                                                                                                  (L/day)
 Chapter 5: Table A of the Hostel                                  150 – 400
 Planning Guidelines for Water Accommodation                                               Total: 18,271 - 51,600
 Supply and Sewage 2010

 Table H4 of Australian / New Motels/hotels
 Zealand Standard 1547:2012
                              Guests and resident
 On-site Domestic Wastewater                                          220                         28,380
                              staff
 Management.                                                        25 - 30                    3,225 – 3,870
                              Restaurant (per diner)
                                                                                           Total: 31,605 – 32,250

Based on current flow data (72 – 114 L/person/day) it estimated that the expansion (129 persons) will generate
between 18,712 and 13,794 L/day. This is significantly less than the volumes provided by the guidance,
however, is reflected in similar developments that FPE have reviewed. On this basis the adopted hydraulic
loading for the Centre post development is 120 L/person/day to allow for variable flows. This equates to a total
daily flow rate of 15,480 L/day.
Peak design capacity
Given the increase in population and associated flow rates it is anticipated that the expansion will trigger the
requirement for the Centre to obtain a permit for an Environmentally Relevant Activity (ERA).
In accordance with section 63(4) of schedule 2 of the Environmental Protection Regulation 2008, the daily
peak design capacity for sewage treatment works is calculated using the following formulae—

EP = V/200 Where — V is the volume, in litres, of the average dry weather flow of sewage that can be treated
at the works in a day.

The peak design capacity for the development has been calculated using the above formula and the peak
occupancy flows to provide the number of Equivalent Persons (EP). This equates to an EP of 78 at full
occupancy during the Centres residential courses.
With reference to the Environmental Protection Regulation 2008 the following Environmental Authority will be
sought:
         ERA 63 Sewerage treatment threshold 1(a)(i) – operating sewerage
         treatment works, other than no-release works, with a total daily peak design
         capacity of 21 to 100EP, if treated effluent is discharged from the works to an
         infiltration trench or through an irrigation scheme.



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