Appendix C - site and soild evaluation for on site effluent.pdf

The size of the Land Application Area is calculated as follows:

  Minimum requirement       q       120           litres per person per day   AS 1547 –2012 Appendix H1

      Water Supply               Tank Water

  Number of persons =                 6                                           AS 1547 Table J1


      Total Volume          Q=      5040      L/week

      Soil Category                   5                                           AS 1547 Table M1

  Indicative permeability         0.06-0.12                                       AS 1547 Table M1

           DIR                       21       mm/week                             AS 1547 Table M1

                                                2
      Disposal Area         A=      240       m

WE RECOMMEND THAT A MINIMUM LAND APPLICATION AREA OF 240m 2 BE PROVIDED.

The Irrigation System should be designed in accordance with AS 1547 – 2012 and comply with all relevant
statutory requirements.

Construction Guidelines for Land Application Areas:

Surface Irrigation

Consists of a reticulated pressurised irrigation system that uses a series of surface sprinklers to equally distribute
the treated effluent across the Land Application Area. This system allows vegetation within the area to directly
benefit from such watering which also assists in disposal of the effluent via evapo-transpiration. Points to consider
in the construction of the area include the following:


             To avoid runoff from the area it should be as level as possible. Any steep sloping areas should be
              terraced or retained and filled.
             Rainwater shall be diverted around the perimeter of the area by use of open catch drains or bunding.
              Similarly a retention bund should be constructed around the low side of the area to retain any effluent
              overflow.
             Sprinklers with a throw of not more than one meter shall be used and produce coarse droplets
              (instead of a fine mist) to minimise the risk of aerosol dispersion and wind drift of effluent. The
              plume height shall not be more than 500 mm above the finished surface of the irrigation area.
             The treated effluent must not be used for the irrigation of fruit or vegetables.
             Siting of surface irrigation shall be in a location away from regular pedestrian traffic and recreational
              areas, so there is no risk of direct spray or wind driven spray onto such areas.
             The area should not be within vehicle paths or be near children’s play areas. Refer to Queensland
              Plumbing and Wastewater Code for all required setback distances.
             Treated effluent quality must conform to AS 1547 - 2012 and the Queensland Plumbing and
              Wastewater Code.

We have attached a site plan showing the proposed position of the Land Application Area and also some details
highlighting the construction techniques required for surface irrigation.




   AUSTRALIAN SOIL INVESTIGATIONS                                  4                             ASI Ref: 240038 (A)