Water Use and Reuse Stream Projects

Holistic solutions to on-site wastewater treatment over a karstic aquifer system in Mount Gambier

Introduction

This research project assessed the impact of on-site wastewater treatment systems on the quality of groundwater in the karstic aquifer from which Mount Gambier’s drinking water supply is drawn. The karst features of the Gambier Limestone aquifer provide the potential for contaminants to be delivered rapidly to the Blue Lake or to water supply wells. This program was funded through the Centre for Natural Resource Management’s National Action Plan for Salinity and Water Quality. It complimented the ‘Fate of Stormwater Contaminants in Mount Gambier’ research program undertaken by CSIRO, which was also funded by the Centre for Natural Resource Management.

Objectives/Scope

The research project provided information on the performance of septic tanks and aerobic wastewater treatment systems, taking into account system type, maintenance, age, capacity and loading, soil type and other site characteristics.

The researchers also sought information from households and businesses with septic tanks and aerobic systems to assist with the assessment, and to gain information about public knowledge of these systems and the social factors that influence effective system management for better health and environmental protection.

The results will inform council policy and promote community engagement in developing an on-site wastewater treatment management strategy for the region.

Some of the key recommendations arising from this project are increased management of wastewater systems, and education programs for the community, with information about on-site wastewater treatment systems and how people can help protect the quality of the local groundwater and Blue Lake.

Activities

• Analysis of effluent from septic and aerobic treatment systems to compare treatment performance
• Development and application of forensic techniques to identify groundwater containing a wastewater component
• Assessment of community attitudes to groundwater protection based on focus group interviews
• Provide a basis for policies and a management strategy for on-site wastewater treatment.

Project publications

Levett, KJ, Vanderzalm, JL, Alexander, KS, Dillon, PJ, Richter, D, White, NJ and HJ, Fallowfield (2009) Holistic solutions to management of on-site wastewater treatment systems over a karstic aquifer used for drinking water supplies. CSIRO: Water for a Healthy Country National Research Flagship.

Alexander, K, Levett, K & Vanderzalm, J (2008) Community views on the management of on-site wastewater treatment systems for the protection of groundwater in the Mount Gambier and Grant Districts, CSIRO: Water for a Healthy Country National Research Flagship.

Alexander, S (2007). Social implications of management of on-site wastewater treatment systems for groundwater protection. CSIRO Water for a Healthy Country National Research Flagship report. Canberra: CSIRO.

Levett, K, Vanderzalm, J, White, N, Fallowfield, H & Dillon, P (2008) 'Towards best practice of on-site wastewater systems in the Mount Gambier region: the effect of management on system performance', in Onsite and Decentralised Sewerage and Recycling Conference 12-15 October 2008, pp. 342-349, Australian Water Association, Benalla, Victoria.

Alexander, K, Vanderzalm, J, Levett, K, Lambden, A, Kinloch, C, Dunstone, B & Jarvis, L (2008) 'Achieving ‘best-practice’ management of on-site wastewater systems through community consultation in Mount Gambier and Grant districts', in Onsite and Decentralised Sewerage and Recycling Conference, 12-15 October 2008, pp. 267-275, Australian Water Association, Benalla, Victoria.

Key CSIRO Staff

• Joanne Vanderzalm, Kerry Levett, Peter Dillon, Kim Alexander (CLW)

Partners

• Centre for Natural Resource Management
• South East Natural Resource Management Board
• South Australian Water Corporation
• South Australian Environment Protection Authority
• South Australian Department of Water, Land and Biodiversity Conservation
• City of Mount Gambier
• District Council of Grant
• SARDI Sustainable Systems
• Flinders University, South Australia
• Freie University, Berlin, Germany

Timeline

2007-2008