Business Paper - Hawkesbury City Council

Waste
The ‘flora and fauna impact assessment prepared by Abel Ecology states that:
“The soil has adequate adsorption capacity such that nutrient control is not a limiting
factor. Sufficient area is available so that water is disposed by evaporation and
transpiration, using underground dispersal so that there is no risk of overland flow of
nutrient to the downslope forest. The disposal area is greater than 40m from any
watercourse. A ten metre (10m) buff is provided between the effluent disposal area
and the sensitive vegetation community on the site, so no adverse impact is
anticipated.”
The Design of the effluent treatment and disposal system includes:
A 100m buffer zone from creek to the east from the treatment system and the
land application area.
Sub-surface irrigation with treated effluent within the playing field area.
Effluent will be disinfected with UV, and dosed with chlorine, prior to
discharge. It is proposed to provide sub-surface drip irrigation at 600mm
centres in the playing field. This shall provide for a uniform distribution of
effluent. The land application area will be 5,500m 2 in size.
Wet weather storage for 9.67 days of storage.
Capacity to cater for 150 persons (guests and staff inclusive).
The existing septic tank and absorption trench which services the manager’s
residence is to be retained. All other existing systems will be decommissioned and
all wastewater will be directed to a new treatment and reuse system.
A “Design Review of a Proposed Wastewater Treatment and Effluent Irrigation
System at Grose Vale, NSW” prepared by Whitehead & Associates Environmental
Consultants P/L dated 6 June 2011was submitted in support of the application.
This Review advises that design flow to the treatment system is expected to be
12,000 litres per day based on a maximum occupancy of 150 persons and a design
daily flow allowance of 80L per person and that this is considered appropriate given
that no full scale laundry facilities are provided and “AAA” rate water saving fixtures
will be used throughout the development.
The Review concludes that:
“The proposed effluent irrigation system is adequately sized and provides an
acceptable level of additional capacity to sustainably manage the expected
wastewater flows from the redevelopment.
Additionally, the proposed wastewater treatment system represents a significant
upgrade form the existing operation and will provide measureable improvements in
irrigation water quality and treatment reliability. The improved irrigation water quality
JRPP (Sydney West Region) Business Paper – (Item 1) (01 September 2011) – (2011SYW020) 15