Launceston’s Combined Sewerage System – investigation and strategy development

Jessup, Cameron (2015) Launceston’s Combined Sewerage System – investigation and strategy development. [USQ Project]


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TasWater operates a combined sewerage system that services the greater Launceston area in northern Tasmania. The operation of the combined sewerage system is of interest to the local community and a number of key stakeholders who are concerned that the design principles, age and performance of the combined sewerage system is causing degradation of the receiving waters into which treated effluent and combined sewer overflows (CSO) are discharged.

he Launceston Combined Sewerage System is the last combined system of note within Australia. Due to ongoing stakeholder concern and limited data for CSO events and system performance TasWater is seeking to understand how the combined system performs. To understand system performance a number of samples were collected and analysed for CSO, treated effluent and stormwater. Data was also extracted from TasWater’s SCADA to develop pump station and treatment plant flow profiles. This allowed for the calculation of annual pollutant loads from each discharge method.

The performance was compared to recognised service levels and performance standards developed by regulatory authorities in the US and UK. The intention of this assessment was to help educate the community about the combined system and to develop capital and operational programs of work to address deficiencies in the system.

The performance was also compared to a theoretical separated system for the area that is currently serviced by the combined system. This assessment was completed as a recurring theme amongst the community is that separation will resolve the pollutant issues in the receiving environment.

The performance analysis of the system indicated that the existing combined system contributes significant pollutant loading to the receiving environment. The existing combined system operation has a number of areas that could be improved through change in operational methods or capital works investment.

The performance analysis also indicated that separation will not resolve the issues that the receiving environment faces. Although separation would significantly reduce the nutrient load that the system contributes to the receiving environment, it would cause only minor improvement in pathogen loading and would actually result in elevated solids loading and metal contamination.

Comparison of the existing system operation and performance against international standards for operation of combined systems, through a high level gap analysis, has highlighted a number of areas where the combined system could be improved. These findings will be used to inform future capital and operational budgets for TasWater.

The results of the performance and gap analysis will be used to provide targeted education for the key stakeholder groups and the community as a whole.

Completion of the research project has identified a requirement for additional sampling and investigation works to confirm the results contained within this document.

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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering Honours (Civil) project
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Aravinthan, Vasanthadevi
Date Deposited: 06 Jun 2016 06:36
Last Modified: 06 Jun 2016 06:36
Uncontrolled Keywords: Combined drainage, Combined sewer overflows, Discharge frequency, Discharge volume
Fields of Research (2008): 09 Engineering > 0905 Civil Engineering > 090509 Water Resources Engineering
Fields of Research (2020): 40 ENGINEERING > 4005 Civil engineering > 400513 Water resources engineering

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