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Frequently Asked Questions

This section contains information regarding the Tilligerry Creek pollution update.

What is the virus and what caused it?

Tests conducted in July this year detected a human stomach virus, called Norovirus, in some oyster samples taken from Tilligerry Creek. 

This virus is only found in humans and is carried in human effluent. Because the Tilligerry area has high groundwater levels, all septic systems relying on disposal of effluent below the ground surface have the potential to contribute pathogens (such as faecal coliforms and viruses) into the groundwater, surface drains and ultimately Tilligerry Creek.

How can it be proven that my septic system is causing any problems?

To determine the individual impact from one septic system on the groundwater and Tilligerry Creek is a complex, time consuming and costly process. It is not always possible to tell if a septic system is or isn’t working just by a visual inspection.

Nevertheless, hundreds of samples from various locations throughout Salt Ash and Bobs Farm have been analysed for faecal contamination over recent years. The results show that faecal matter was present and that a significant amount of the contamination was from human sources.

There are other tests that involve the use of tracers to determine the flow path of effluent from the disposal area, however these cost between $1000 to $5000 per site.

Instead of undertaking these flow path tests council have accepted other studies (see below), which consistently show that below ground disposal systems in high groundwater areas contribute to groundwater contamination.

(Studies include: NSW Food Authority Study of Tilligerry Creek, University of Newcastle Study into Septic Systems at Salt Ash, and Port Stephens Council University of Newcastle investigations into faecal contamination of salt ash drains.)

Why do I need to upgrade my system in 2 years if it’s working well?

Council issues annual approvals to operate septic systems. Having regard to the recent findings, it would appear as though many existing systems are inappropriate because of the contamination of groundwater and the threat to Tilligerry Creek.

The Local Government (Approvals) Regulation does not permit the issue of an approval to operate if groundwater is being contaminated.

Therefore, even though these systems have existing installation approvals, the ongoing issuing of Approvals to Operate by Council is in jeopardy.

Council is giving these residents two years to implement a system that is environmentally appropriate. This time period is considered appropriate having regard to the urgency of the situation balanced with the financial burden to homeowners in upgrading their systems.

Why should I upgrade my system that was previously approved by council?

Property owners obtained an original approval to install a system that was considered environmentally appropriate at the time and was common across NSW. Subsequent annual approvals to operate systems have been issued by Council since 1998.

The full impact of on-site sewage management systems on an area such as Tilligerry Creek was unknown until recently. Recent findings have shown that many existing systems are inappropriate because of the pollution to Tilligerry Creek and the contamination of oysters.

Residents are responsible for the safe operations of their own individual septic systems. Council plays a role in monitoring the septic systems to ensure that they are performing to established standards, however as the septic systems are owned by the householder, the upkeep and upgrade costs are the owners’ responsibility.

Residents need an approval from council to operate a septic system. This approval to operate specifies that certain environmental standards be met including the protection of surface and ground waters. If these conditions are not being met then the resident will not be granted a license.

Why can’t I wait until the area is connected to a conventional sewer system?

Port Stephens Council is not the delegated authority for reticulated sewer; this responsibility lies with Hunter Water Corporation. The State Government is responsible for determining which localities will be allocated funding for the installation of new reticulated sewerage systems. Additionally, there is no guarantee that a conventional sewage system would be the most appropriate system for Salt Ash and Bobs Farm.

The State Government is engaging a consultant to investigate the feasibility of a sewage system to service the Salt Ash/Bobs Farm area. The study should be completed by June 2006. The design, environmental studies, and final construction of a sewage system could take many years. The sewer system for Karuah, which had similar problems to Tilligerry Creek, took over 10 years to complete after funding had been allocated.

The problems in Tilligerry Creek and drains are too significant to delay urgent action. The issue is not just a problem for oyster farmers; it has become a localised human health and broader environmental issue.

What options/solutions were considered?

The Commonwealth and State governments and Port Stephens Council have considered a number of different solutions for the short, medium and long term.

These included:

• The Wisconsin Mound System. Cost $5,000 – $9,000 for installation
• Pump out systems for all failing septic systems, cost was approx. $5,000 installation and a $3,000 annual fee.
• Installation of a mini treatment plant with disinfection and a mound. This is the minimum requirement for new properties in areas of high ground water. Cost $16,000 - $20,000

All new properties in areas of high ground water will have to install a mini treatment plant with disinfection and a mound. This system is superior to the Wisconsin mound connected to a single septic tank as effluent is treated to a secondary treatment standard before being disposed of into the mound.

For existing properties, residents will be required to install the Wisconsin mound system without secondary treatment. This is less expensive and will provide a higher level of protection to ground water contamination than traditional septic systems.

An investigation is being commissioned by the State Government to determine the viability of a sewerage system as a longer-term solution. The estimated cost of this system is approximately $40,000 - $50,000 per property which is usually subsidised by Government.

How effective will the mound system be at removing faecal contamination?

The Australian standard (AS1547:2000) for domestic onsite wastewater systems recommends mound type systems for high ground water table areas.

Scientific studies have shown that mounds are effective in helping to treat and minimise faecal contamination from septic systems.

The design of the mound minimises the infiltration of effluent in dry and wet conditions due to its size, shape and construction.

They are therefore far superior to a traditional below ground septic system.

Contact details
Environmental Services Unit
02 49 800 164 (ph)
council@portstephens.nsw.gov.au

© 2008 Port Stephens Council
This page: http://portstephens.local-e.nsw.gov.au/environment/1273/44036.html