220239 - 44 Williams Road, KIN KIN - SSE - TE222036 - 44 Williams Road, Kin Kin QLD 4571 (1) (1)

4     Secondary Dwelling
4.1     Soil Investigation
The soil profile and design characteristics for the secondary dwelling effluent disposal area are
presented in Table 4.

Table 4: Soil Type
      depth                                BH9                      depth                           BH10
                            Silty clay (CL), low plasticity                                    Clayey sand (SC)
       200                                                            200
                                 Cat 4 – moderately                                             Cat 3 - massive
                         Silty clay (CL), medium plasticity                        Silty clay (CL), low-medium plasticity
       700                                                            500
                                 Cat 5 – moderately                                            Cat 5 – strongly
                      Silty clay (CL), low-medium plasticity                                   Clayey sand (SC)
      1500                                                           1500
                                   Cat 5 – strongly                                             Cat 3 - massive
                            Silty clay (CL), low plasticity                                    Clayey sand (SC)
      2000                                                           2500
                                 Cat 4 – moderately                                             Cat 3 - massive
                                                  Design Characteristics
 Texture                                          Clay Loam / Light Clay
 Category                                         5
 Indicative Permeability (Ksat)                   0.06 – 0.12 m/day
 Adopted Design Loading Rate (DLR)                10 mm/day


4.2     Wastewater System
A shed near the new second dwelling has unapproved plumbing, with a septic tank and trenches. The
plumbing is to be abandoned and capped permanently so that it is no longer useable. The trenches
are to be abandoned. The concrete septic tank is in good condition and is to be retained for use by
the dwelling. Table 5 below presents the features of the AES system for the secondary dwelling.

Table 5: Design Features
                                Feature                        Details
                                Septic tank capacity           3900 L (existing)
                                Treatment plant                Advanced Enviro Septic (AES)
    Treatment System
                                Treatment plant approval       15/2019
                                Treatment level                Advanced secondary
                                Water supply                   Rain water
                                Volume Allowance               120 L/person/day
      Design Volume             Number of bedrooms             2
                                Design population              3
                                Total Design Volume (Q)        360 L/day
                                Category                       5
    Soil Characteristics
                                Design Loading Rate (DLR)      10 mm/day
                                                               Width = 2.61m
                                                               Length = Q / (DLR x Width)
                                Required disposal area                = 360 / (10 x 2.61)
      Disposal Area                                                   = 13.8m
                                                               Area   = 36 m2
                                Install as                     2 [email protected] x 2.61m each
Site and Soil Evaluation                                                               44 Williams Road, Kin Kin QLD 4571
Taylor Environmental (Australia) Pty Ltd                                                                      Page 5 of 19