Eurobodalla Integrated Water Cycle Management Strategy

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Eurobodalla Integrated Water Cycle Management Strategy
Another alternative is to upgrade the septic system to one that achieves nutrient removal
and therefore results in a higher quality effluent discharge (e.g. aerated tanks). This would
increase the potential uses available for the resulting treated effluent.
Both these options would minimise the potential of groundwater contamination and its
associated environmental impacts, as well as reducing the likelihood of public health issues
and odour complaints.
Enhanced Management of Existing On-site Facilities with Greywater Reuse
In this opportunity blackwater (water from kitchen sink and toilet), and greywater (water
from laundry and bathroom), would be managed separately. The blackwater would be
treated in the existing septic tanks with regular pumpouts and the greywater would be
treated on-site using an advanced technology such as aerated tanks. The treated effluent
could then be recycled for garden watering and toilet flushing.
In addition to reducing the amount of imported reticulated water, this would conserve
harvested roof rainwater. With the implementation of an appropriate monitoring system,
long term environmental and water resource sustainability and public health protection
could be achieved.
Centralised Management of Effluent from On-site Facilities
As an alternative to providing a full reticulated sewage system, the effluent from existing onsite
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 conventional gravity sewerage, as the pipes carry only
liquid effluent. The solids are captured by the on-site system.
The effluent could be treated locally or transported to Batemans Bay STP. Appendix P
provides information on the various effluent transport and local treatment options.
Treating effluent at a local facility would result in a number of options for the management
of reclaimed water. Preliminary appraisal suggests dunal infiltration, agricultural reuse
(possibly at the Princess Highway) and controlled groundwater injection for subsequent
extraction as the most suitable options worthy of further evaluation.
Costs in Table 9-1 are based on centralised effluent drainage (CED) for transport, a local
package plant for treatment and dunal infiltration.
Provision of Full Reticulated Sewerage System
An alternative to on-site treatment facilities is to transfer wastewater (i.e. black and
greywater) through a centralised sewer transport network to either a local treatment facility
as discussed for the previous opportunity or to the Batemans Bay treatment works. Unlike
the previous opportunity, the sewer transport pipes would need to be larger and possibly
installed at greater depths.
Appendix P provides a detailed description of the available transport and local treatment
options. The shortlisted reclaimed water management options are the same as those
discussed for the above opportunity.
Costs in Table 9-1 are based on a modified gravity transport system, a local package
extended aeration treatment plant and dunal infiltration.