App 5 - Wastewater Design

3.3 Soil Classification



                                                   Soil Classification - Adopted
        Borehole Nos                                                                                 1&2
        Soil Category Adopted                                                                          5
        Indicative Drainage                                                                    Poorly Drained
        Structure                                                                                  Strongly
        Texture                                                                                  Sandy Clay
        Indicative Permeability P (m/d) as Ksat*                                                  0.12 - 0.5
        Recommended DLR(AS/NZS 1547 / 2000)                                                           10




     4.0 Recommendations:
     4.1 Treatment Facility:
     The on-site treatment facility to service the new detached dwelling is to be an Advanced Enviro-Septic System (AES).
     This system has a Chief Executive Approval # 14/2014 for Advanced Secondary Effluent. The Equivalent Person
     (EP) for this system is to be no less than 2.

     A new min 3000lt septic tank is to be installed to service the amenities in the shed/workshop and stables. This tank
     must comply with AS/NZS:1546. All wastewater from these amenities is to be directed to the septic tank then to the
     AES bed.

     The Land Application Area is to be an Advanced Enviro-Septic Infiltration Bed of 24m2.




      5.0 Design Calculation
      The serviceable life of the Land Application Area will be compromised if the design flow is exceeded. Any
      proposed changes to the position of the Land Application Area, System Type or House Design will require a
      reassessment of this site. For our calculations we have assessed the design flow as follows:

                                                    Design Calculation
         DLR (mm/d) (secondary quality effluent)                                                     10
         Hydraulic load (lt/day/person) Tank Water / 1 bedroom equivalent                            120
         Design Flow Q (lt/day)   EP: 2                                                              240
         Design sizing calculation                                                           L = Q /(DLRxW)
                                                                                                = (240 / 10)
         Disposal area A+B (square metres) AS/NZS1547:2000                                          24m2
         Nominated Configuration (metres) AES System Design Calculations               = 6.6 x 3.64m (L xW) 24m2
         A new 3000L Septic Tank is required.                                                AES System EP 2




                                                                                  C Copyright Lance Picton 2019 design & content. 3/10