Pyrenees Shire Council: Snake Valley Wastewater Collection & Treatment System
Posted under: In 2009, the township of Snake Valley faced serious environmental health issues with sodden ground, faulty septic tank systems and overland flows within the township. In an effort to improve the health and wellbeing of the community, the Pyrenees Shire Council (Council) developed a Septic Tank Effluent Pumping Scheme (Project) for Snake Valley that services 120 households and has the capacity to meet future demand, accommodating up to 200 households. The sewerage treatment works, winter storage and reuse system is located partly on unused road reserve and crown land and the treated effluent is used to sustainably irrigate the local golf course. The total cost of the township collection system, treatment plant, design and contract management was $2,525,000. The facility has resulted in positive outcomes for the community, local economy and environment. This Project demonstrates Council understanding of the local environment and considerate of community needs and is a reflection of Council’s ability to manage future planning and development prospects for the town.
2 Description of project
2.1 Project objectives
In late 2008, in the context of the improvement of community health and wellbeing while also recognising reduced water availability, Council set about investigating improving septic wastewater systems within the township of Snake Valley. Council’s main aim was to produce a cost effective long-term waste collection and usage system that impacted positively on the health of the community and local environment.
Prior to the installation, Snake Valley was constrained primarily by the absence of a reticulated sewerage system. Post investigation, the most feasible scheme for Snake Valley was deemed a common effluent sewerage scheme; which makes use of existing private septic tank infrastructure in the town, combined with a secondary pondage style communal treatment facility.
Objectives include;
– Improve the general health of the community and minimise the environmental impact of overland flows caused by ineffective septic dispersion systems.
– Develop a cost effective long-term solution to local landholders, who would otherwise be required to upgrade existing systems with more expensive onsite domestic treatment systems.
– Reduce onsite seepage and flows of sewerage eliminating biological pollution (evident in analysis of surface water in drains).
– Create an effective and cost efficient scheme for the community that meets future demand. Snake Valley has been experiencing accelerated development pressure as a consequence of the rapid outward expansion of Ballarat.
– Provide a sustainable irrigation system for the local golf course.
2.2 Project outcomes
The new sewerage scheme has resulted in the majority of local households having a well maintained septic tank, fitted with a discharge pump so that effluent is pumped via a pressurised reticulation system to a central collection point. Effluent is then pumped to a system of lagoons adjacent to the golf course land, with a winter storage facility being there. The treated effluent is used to sustainably irrigate the local golf course.
Economic Outcomes
– Over a 25 year lifespan, analysis shows the Project will cost $1.5 million less than alternative wastewater solutions.
– Initial capital cost to landowners was higher than alternative options. Council combated this by developing a policy of financial contributions to assist landowners bear the additional cost.
– Utilising existing domestic septic tanks lowers the need and cost of constructing deep conventional sewers.
– Gravity collection system (the alternative option considered) would have been costly to construct due to variations in local topography and rocky sub-surface conditions, making trenching difficult.
– This Project facilitates housing development and urban consolidation, attracting more people and businesses to the township of Snake Valley.
– The Project is a more cost effective long-term solution to local landholders, who would otherwise be required to upgrade existing wastewater systems with more expensive onsite domestic treatment systems. In some areas the land capacity makes it impossible for any septic dispersion to function properly.
Environmental Outcomes
– Treated effluent being used to sustainably irrigate the Snake Valley Golf Course.
– Previous septic dispersion systems and domestic connection practices had created a general health risk to the community. There was documented evidence of pollution within the town from septic effluent due to failing septic systems and saturated ground on small lots.
– The chosen system performs the primary waste treatment in the domestic septic tanks, reducing the size of the treatment lagoon by 30% and lowering the risk of odour at the plant.
– As the collection system is pressurised, smaller diameter pipes and only modest trenching was required for undergrounding the service.
Community Outcomes
– Improved overall environmental health of the local community.
– Ensures up to date infrastructure for the majority of the community which contributes to the urban character and urban amenity of Snake Valley.
– The Project satisfies current community needs but also sufficiently meets future demand and can accommodate up to 200 households.
– A strong collaborative relationship has been formed between Council and the Snake Valley Golf Club who have been prepared to support and encourage Council with this project.
2.3 Innovative features of the project
The Project has a number of features that influenced Council’s decision to select this scheme over alternative options; mainly the use of existing infrastructure. Making use of existing private septic tank infrastructure which takes effluent to a secondary pond style communal treatment facility was seen as a benefit as it reduced the costs to landholders as deep sewers were not required. Using existing tanks also reduced the risk of blockage. Another feature of the scheme is the pressurised sewerage treatment system. Primary treatment is done in the individual septic tank, which reduced the need for a major pumping and treatment plant and the subsequent costs associated with construction and power. Effluent pumping sewers have small diameter pipes that follow the contour of the land and are only buried a metre or two underground. While an effluent sewer can use gravity to move waste, the ability to move waste with a pressure system can be a big advantage in places where a gravity system is impractical.
2.4 Distinguishing features of the project or service highlighting best practice engineering principles and technologies
• The benefit of this construction type was that it allowed trenchless construction methods for the transfer mains within the township and out to the treatment plant.
• Each property within the township was surveyed to assess the works required to ensure wastewater plumbing compliance.
• Council has stipulated that any property connecting to the system must have all fittings compliant with the appropriate code and undertaken by a qualified plumber to be eligible for a $2500 rebate.
2.5 Benefit to the community of the project or service
Snake Valley is one of the few rural townships in the Pyrenees Shire experiencing positive population growth. The increasing rate of residential development over recent years has prompted a need to review development trends, growth potentials and associated planning issues for the township. This Project has enabled Council to plan for positive future population growth, demonstrating to the community that it is committed to accommodating for an increase in population and development opportunities. Importantly, it give residents confidence in their Council and pride in their town. The benefits are varied and include positive environmental, economic and community outcomes. The health of the community is paramount; while it is challenging to assign a response in the general health of the community to the installation of the new sewerage system, it can be safely assumed that improving domestic disposal of waste will invariably mitigate health risks. The environmental benefits are significant. The lack of available water has encouraged Council to develop a sustainable irrigation solution for the local golf course and create a sustainable waste management system for the community for years to come. In future years with expansion the system may be used to irrigate at the local recreation reserve.
2.6 Program and project management.
This Project was overseen by Council and is managed on an ongoing basis by Central Highlands Water. A number of barriers were overcome by Council including seeking funding for the works, along with the general topography, landscape and soil composition of the town. Understanding the implications of a common effluent sewerage system on future planning and development opportunities, Council’s foresight in commissioning a preliminary assessment and feasibility study in 2008, by a respected engineering firm, ensured that it was armed with compelling information to seek funding. To mitigate funding barriers, Council worked collaboratively with the Department of Environment and Sustainability and Central Highlands Water Corporation to produce detailed feasibility studies that produced viable information worthy of funding support from both the Commonwealth and State Governments.
2.7 Costs/Benefits associated with the Project
It is understood that this Project incurs considerable capital and operational costs for Council, funding partners and local community to manage over the next 25 year lifespan, however Council is confident that the most cost-effective method has been selected for the Snake Valley community.