Attachment F - Effluent disposal report

WE WOULD RECOMMEND THAT A SECOND 10 PERSON DOMESTIC AWTS SYSTEM BE
INSTALLED WHEN THE ON-SITE EMPLOYEE NUMBER EXCEEDS 50.

Construction Guidelines for Land Application Area:

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 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 praduce 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 300 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
» Treated effluent quality must conform to AS 1547-2000 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.

Preparation of irrigation area:

When a proposed irrigation area has a low permeability, it is particularly important to ensure that the
permeability of the soil in the irrigation area is improved and maintained and that there is an adequate
cover of porous and fertile topsoil to act as immediate storage of effluent applied to it, and to support
rapid growth of vegetation on the area to maximise evapo-transpiration.

It is recommended that topsoil be imported to improve rapid growth of vegetation and improve the
evapo-transpiration process.

Requirements of irrigation system:

Note: A Pump well with suitable pump to operate an Indexing valve will be required at the
Irrigation area in order to ensure equal dosing of disposal area. This pump well is to receive
the pumped effluent from the AWTS.

All irrigation pipe work and fittings shall comply with all parts of AS 1477 or AS 2698.2. The distribution
irrigation lines should be buried to a minimum depth of 100mm. There shall be no cross connection

AUSTRALIAN SOIL INVESTIGATIONS ASI Ref: 150105(A)