Att11 - Land Suitability (effluent) Report

FPE Ref: 6195-220404-1.0



  4.0 LAND APPLICATION SYSTEM – EFFLUENT DISPOSAL

          DISPOSAL METHOD

  On the basis of the above assessment, a number of options are available for the disposal of advanced
  secondary treated wastewater on the proposed site. Due to the presence of poorly draining subsoils,
  conventional absorption trench or ETA (evapo-transpiration absorption) systems are not considered the
  most appropriate method for disposal of wastewater on the proposed allotment.

  In this case, the preferred method of disposal is a surface irrigation system.

          IRRIGATION SYSTEM DESIGN

  The disposal of effluent treated to an advanced secondary standard, may be achieved via surface
  irrigation system. Standard drawings of typical surface irrigation, is provided as Appendix D of this report.

  The design method used for sizing of the surface irrigation system can be calculated using the Design
  Irrigation Rate (DIR) calculation as set out in Table M1 of AS1547:2012.

  From Table M1 of AS1547:2012, the following Design Irrigation Rate’s (DIR) have been adopted for the
  proposed development.

  Table 5. Design Irrigation Rate for Application Systems

                           AS1547:2012 Soil Category          Design Irrigation Rate

                                  Soil Category 6                      2mm/day

  Based on a hydraulic loading of 32,000L/day, as specified in section 3.3 of this report, the minimum area
  required for disposal using an irrigation system has been illustrated below:

  Table 6. Minimum Required Irrigation Area

                                                            Irrigation Area as
                                    AS1547:2012 Soil          Determined by
                                        Category               Table M1 of
                                                               AS1547:2012

                                      Soil Category 6            16,000m2



  All irrigation piping is to be installed to a minimum depth of 150-250mm below the ground level and turfed.
  Where slopes exceed 10% and surface irrigation is adopted the disposal area will need to be terraced or




20 April 2022                                Land Suitability Report                                              9
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