Eurobodalla Integrated Water Cycle Management Strategy

146
Eurobodalla Integrated Water Cycle Management Strategy
pumpout. The cost of this pumpout could be evenly divided between the residents. To
facilitate pumping every tank would require a smaller holding tank or pumpout facility.
This opportunity would reduce the issue of wastewater contaminating the local aquifers and
waterways, but may lead to additional community issues in relation to odour and noise
during pumpout and frequent movement of trucks in the neighbourhood.
Enhanced Management of Existing On-site Wastewater Facilities
There are several options available to upgrade the existing on-site wastewater
management systems to achieve greater public health and environmental outcomes. The
first option is to retain the existing septic tank and upgrade the on-site wastewater
management system. An example of this would be the replacement of the adsorption
trenches with lined evapotranspiration beds, which achieve a higher level of water and
nutrient uptake through plants.
Another alternative is to upgrade the septic system to one that achieves nutrient removal
(e.g. aerated tanks) and therefore results in a higher quality wastewater discharge. This
would increase the potential uses of the treated wastewater.
The enhanced management of the current on-site systems would minimise the potential
risk of pollution contaminating the lagoons and waterways as well as reducing the likelihood
of public health issues and odour complaints.
Centralised Management of Effluent from On-site Facilities
As an alternative to providing a full reticulated sewage system, the wastewater from existing
on-site systems (e.g. septic tanks) could be collected and transported to a central treatment
facility. This type of system relies on smaller pipes than those required for a conventional
reticulated sewerage system. Pipes can be laid in the ground at a lesser gradient and at a
more shallow depth than that of a conventional gravity system, as the solids are captured by
the on-site system and the pipes only need to carry liquid wastewater. The wastewater
would be transported to Tomakin STP for treatment.
Provision of Full Reticulated Sewerage System
An alternative to on-site sewerage treatment facilities is to transfer wastewater through a
centralised sewer transport network to Tomakin STP. This opportunity would require the
provision of larger pipes than for the previous option, which would possibly require being
installed at greater depths.
Provision of Full Reticulated Sewerage System with Grey Water Reuse
On-site systems that achieve a suitable level of treatment for greywater would be
maintained, and blackwater only would be transported to the STP using the reticulation
systems described above. The resulting greywater could then be utilised for a variety of
outdoor uses and for toilet flushing. Maintaining current aerated systems in Rosedale and
Guerilla Bay for greywater reuse would reduce the volume of wastewater requiring
treatment by 4 ML/a. In addition to reducing the volume of imported or reticulated water
required for Rosedale and Guerilla Bay, this would reduce the hydraulic load on the
Tomakin STP. With the implementation of appropriate monitoring systems, long term
environmental and water resource sustainability and public health protection could be
achieved.
Provision of Full Reticulated Sewerage System with Grey Water Reuse and Roofwater
Harvesting
This opportunity incorporates components of the previous opportunity. Systems that are not
suitable for greywater reuse (e.g. septic tanks) would be de-sludged and disinfected and
used to collect roofwater for non-potable uses including garden watering and toilet flushing.