2016-07-12 - Item 14 - Att 1 - Effluent Disposal Planning Study

1. Executive Summary
Our developed world offers a variety of lifestyles and places to live, work and play. Always though,
lying in the background is a vital system of pipes and plant that deal with our liquid wastes. In our
urbanised places the collection and disposal of liquid effluent is on an industrial scale with a
sophisticated network of pipes, pump stations and advanced treatment plants. For other places
such as smaller settlements and rural situations, domestic effluent is predominantly disposed of
on-site.

We have these systems because our generated liquid wastes can be harmful to human health and
to the environment. Human illnesses associated with failed on-site treatment can be caused by E.
coli, Giardia, Hepatitis A, Cryptosporidium and salmonellae.

Noosa Shire is no different in respect to liquid waste and has features typical to regional Australia
with a mix of sewerage systems and on-site disposal. Several towns and settlements are
unsewered with on-site disposal methods utilised, as is also the case in all rural localities. The key
aspects of on-site disposal are a holding tank, a treatment process and the release of treated liquid
to the ground at surface or sub-ground levels. The released liquid can have differing levels of
contaminants depending on the system. The receiving environment is also variable such that the
cumulative impacts of released waters from a multiplicity of systems can have the potential to
cause deleterious effects on local ecosystems including waterways. The system installed should
best reflect the needs of the individual circumstances.

The installation and management of an on-site waste water treatment system is regulated by
Queensland legislation (Plumbing and Drainage Act 2002) and implemented by Noosa Council. A
substantial study of on-site wastewater treatment in Noosa Shire was undertaken in 1995-97 as
part of the background investigations that lead to the Noosa Shire Strategic Plan 1997. With a new
Planning Scheme proposed by Noosa Council, it is timely to again consider the circumstances of
on-site disposal. Technological improvements have taken place since the mid 1990s and this
study considers whether there are any implications for managing development in unsewered
localities.

This study concludes that while there have been advances in the technology available with
treatment systems, they generally require a degree of management by the homeowner to deliver
the predicted standards of the effluent discharged. That standard of management is variable in
practice, lessening the average standard of discharge and the reliance that can be placed on such
systems in vulnerable circumstances. Where there are potential risks to human health and
environmental values, caution is warranted. In addition, the Queensland Government is currently
investigating options that will lead to an improvement in the operation of existing on-site systems.
What is also highlighted herein is the universal lack of comprehensive testing and research into the
travel of discharge across and below the varied types of receiving environments.




On-Site Effluent Disposal in Noosa Shire 2016                                                  Page 2