Education Resources : Water Recycling
Water Recycling
Water Recycling Unit (Geography) for Secondary Schools
Introduction
Water is a precious resource, yet less than 10 per cent of the water used by urban and industrial consumers in Australia is recycled. Melbourne Water has committed to achieving 20 per cent water recycling by 2010, and is undertaking studies and actively seeking opportunities to expand water recycling projects.
Melbourne currently uses about 480 000 million litres of water each year of which 60 per cent is for residential use. Many uses do not require drinking quality water and could use recycled water from Melbourne's two sewage treatment plants. We regard recycled water as a precious resource. Increasing the use of recycled water helps conserve drinking water supplies, lessens the impact on the marine environment and makes use of this valuable resource.
Sewage includes everything that goes down the kitchen, laundry and bathroom sink, as well as what is flushed down the toilet. The sewage flows through the sewerage system to the Western and Eastern treatment plants. Here it is treated to environmental standards that are set by EPA Victoria to make it safe for release back into the environment. The treated sewage (effluent) is discharged to the bay or is recycled. Recycled water can be used for a number of purposes including nurseries, market gardens, vineyards, golf courses and sports grounds.
The Eastern Treatment Plant in Bangholme and the Western Treatment Plant in Werribee treat approximately 300,000 million litres of sewage each year. About 10 per cent of treated effluent from the Western and Eastern treatment plants is currently recycled onsite at the plants or offsite by businesses such as nurseries, market gardens, vineyards, golf courses and sports grounds. Melbourne Water is spending almost $300 million on upgrading our sewage treatment plants, which will result in high-quality effluent suitable for a wide range of water recycling projects.
Maximising Water Recycling Opportunities
In 1992, Melbourne Water initiated a landmark, four-year study to identify ways of protecting the long-term health of the Bay. The $12 million Port Phillip Bay Environmental Study, principally funded by Melbourne Water and managed by the CSIRO, found the Bay was healthy by world standards. It was, however, recognised that unchecked nutrient loads, particularly nitrogen, would take the Bay close to the point where significant ecological changes would occur through increased algal blooms and, eventually, eutrophication. Effluent discharged from the sewage treatment plant is a major source (approximately half) of nitrogen entering Port Phillip Bay, and a major $124 million upgrade of the Western Treatment Plant is under way to increase nitrogen removal, maximise water recycling and capture gas by-products of the sewage treatment process to generate power for the plant.
Melbourne Water is investing $47 million to reduce the ammonia content of treated effluent from the Eastern Treatment Plant. This project will reduce ammonia in treated effluent by 75 per cent by June 2006. This will result in a significant improvement in the marine environment at Boags Rocks.
As part of the White Paper water reform package, Securing Our Water Future Together, the Government announced that a feasibility study would be undertaken to transfer recycled water from the Eastern Treatment Plant to the Latrobe Valley. The Latrobe Valley feasibility study could lead to a massive infrastructure project that has the potential to use up to 80% of the Eastern Treatment Plant's treated effluent.
For up-to-date information on water recycling in Melbourne, visit www.melbournewater.com.au/recycling
Learning Outcomes
Level 5
5.2 Explain how natural processes and human activities change environments.
5.3 Explain how people's use of natural and human environments changes over time.
5.4 Develop a plan to address impacts of change.
Level 6
6.3 Predict the effects of resource development and use on a selected natural and human environment.
6.4 Develop a comprehensive strategy to resolve an issue related to the use and management of a natural or human environment.
It should take about 5-6 lessons to complete all the activities.