Penshurst is the most densely populated unsewered small town within the Southern Grampians Shire.

A septic system audit conducted by the shire several years ago showed that 93 per cent (189 in total) of the septic systems inspected were not performing satisfactorily and did not meet current public health and environmental standards.

The town is located in a sensitive groundwater environment that is susceptible to pollution from septic systems. Installing pipes and other underground infrastructure is challenging due to the presence of volcanic rocks.

Funding for the Pilot project has been provided by the Victorian Government, Southern Grampians Shire Council and Wannon Water.

Wannon Water, the Southern Grampians Shire and the Department of Energy, Environment, Land, and Climate Action (DEECA) have worked together to find a sustainable solution to address the impact of failing septic systems across the town.

This will involve dividing Penshurst’s 270 properties into 12 neighbourhood precincts based on their topography and the nature of the land use. Existing on-site systems in each precinct would be bypassed temporarily and separate gravity all-waste sewers installed instead.

The sewers would direct raw sewage and grey water from properties to a local precinct water recycling system, where it would undergo primary treatment before being disposed of through evapotranspiration “pods”.

The natural pod systems provide further treatment in the soil and allow water and nutrients to be taken up by plants and evaporated. The recycled water is then stored and used for public irrigation of open spaces when necessary. The majority of infrastructure for each system would be located on public land, irrigation networks will be under the ground.

Pilot program

The pilot project is fully funded so there won't be any cost to participating property owners.

Potential future cost

If the pilot is successful and the system rolls out more broadly, it's estimated that the cost to property owners would be around $750 a year in service fees (or $375 for eligible concession card holders) plus connection fee. There would be no further connection fees for participants in the pilot project.

The annual service cost is less than the cost to keep and maintain a septic system.

We're conducting a pilot trial to test the adaptive sewerage servicing concept on a smaller, measurable and lower-risk scale before deciding whether the system could be rolled out across Penshurst and other similar unsewered townships.

The pilot involves trialling the treatment of raw sewage from 25 existing properties in a selected precinct. The treated recycled water will be used to irrigate public open space via a below-ground irrigation system.

The pilot will allow the project team to test the scheme's effectiveness and identify any specific requirements.

It will also provide an opportunity for the community to see how it will impact the town and for Wannon Water to develop a 'proof of concept' using an adaptive pathway approach to wastewater management which has the potential to deliver better environmental, public health, social and economic outcomes in other unsewered townships.

On-property Monitoring Program

The first step in of our current trial is to obtain data and information on the existing situation in Penshurst through a baseline monitoring program. This will allow us to determine the performance of the pilot project and its overall ability to meet project objectives of a safe and reliable sewer system.

It will also quantify any shortcomings relating to environmental, human health and community liveability. Once the wastewater management and recycling system is commissioned, we’ll conduct a verification monitoring program. This will allow us to compare the results with the baseline monitoring and determine the benefits. The monitoring wil include water quality samples from the local waterways.