Geographical process

Introduction

The case study chosen for this topic explores the issue of wastewater recycling in Australia, as a sustainable approach to both waste management and water management. Australia is the world's driest inhabited continent, yet Australians have one of the highest levels of per capita water consumption in the world. Many parts of the continent have been experiencing prolonged drought conditions for many years, meaning that the issue of depleting and degraded water supplies is now one of the country's most pressing environmental concerns. The suggestion to recycle treated wastewater (or reuse sewage effluent and other forms of liquid waste), so that it can be reintegrated into drinking water supplies, has therefore received consideration in many Australian towns and cities over the past few years.

This case study focuses specifically on a proposal, put forward in 2005, to introduce a wastewater recycling scheme for drinking water in Goulburn, New South Wales (NSW). This chapter will explore the environmental conditions in Goulburn which led to the need for water management reform, examine the process of wastewater recycling and discuss this timely, yet controversial, issue in an Australian context.

Goulburn's water crisis

Goulburn has a population of over 20 000 people and was one of Australia's earliest inland settlements. It is located north-east of Canberra in the Southern Highlands region of New South Wales (NSW), at the confluence of the Mulwaree and Wollondilly Rivers. See image 1

For the past five years, Goulburn has been experiencing extreme drought conditions. The issue of water availability, along with the associated negative environmental, social and economic impacts is now a serious concern. As at September 2006, all three of the town's dams were well below capacity. Goulburn's major supply of water comes from the Pejar Dam, which has the capacity to hold 9000 megalitres of water. Sooley Dam (Goulburn's second-largest water supply) and Rossi Weir are other sources of drinking water for the town.

Availability of water in Goulburn became a serious concern in 2000, which is when water restrictions were introduced on a permanent basis. At times, the water levels of the three dams reached such lows that some of the town's sewerage pipes became blocked because they did not had enough water running through them to enable their adequate flow. See image 2

Level two water restrictions were introduced in Goulburn November 2002 when the Pejar Dam was only 66 per cent full. Over the next two years, water restrictions, ranging from level two to level four, were permanently in force, depending on fluctuations in water levels of the town's three dams. In October 2004, water became so scarce that restrictions reached level five, the highest possible level. At level five restrictions, residents are urged to consume no more than 150 litres of water per day. Most people in Australia, on average, use about 350 litres of water per day. See animation 1

The 'Goulburn Mulwaree Council Sustainable Cities Project'

Prolonged periods of drought and below-average rainfalls necessitated a drastic reconsideration of the manner in which Goulburn had been sourcing its drinking water supplies. In a social sense, the long-tem water restrictions had already impacted negatively on the town. It was believed by many that this would also soon translate into adverse economic impacts. Local businesses, for example, have already suffered as water supplies continue to dwindle (social and economic impacts will be discussed more in the next chapter). The local council therefore needed to act before the situation worsened. See image 3

In June 2005, the Goulburn Mulwaree Council submitted an application to the National Water Commission (an initiative sponsored by the federal government) for a funding grant under the Commission's 'Water Smart Australia' program. The application asked for monetary support to help the council implement a new project, designed to address the many problems the town was facing as a result of water shortages. The proposal, which will form the basis of this case study, is called 'Goulburn Mulwaree Sustainable Cities Project' (hereon in referred to as the 'Sustainable Cities Project').

Brief overview of the sustainable cities project

The key focus of the Sustainable Cities Project was the Goulburn Mulwaree Council's plan to implement an innovative system for increasing Goulburn's water supply, which would involve the reuse of treated household waste matter (or sewage effluent) to augment (top up) the town's drinking water supplies.

An important element of the wastewater reuse plan involved the construction of a new wastewater treatment plant and a new water reclamation plant. Once constructed, the wastewater treatment plant would treat sewage to a secondary level and the water reclamation plant would release drinking water into the nearby Bumana Creek. From there, the discharged water would pass through a wetland system (which comprises a sequence of ponds that act as a natural filter) within Bumana Creek, before flowing into Sooley Dam to supplement Goulburn's second-largest source of water.

In addition to this, the Sustainable Cities Project also included some other sustainable environmental initiatives. One such initiative included proposals to increase the use of renewable sources of energy, such as wind-power, in the town.

Another initiative was a plan to create large tree plantations to help reduce levels of carbon in the atmosphere. This process, known as carbon sequestration, involves reforestation (the process of replanting vegetation on a large scale) in order to create 'carbon sinks'. A carbon sink is something which reduces the amount of greenhouse gases (such as carbon dioxide) present in the atmosphere. Areas where plants and trees are growing are classified as carbon sinks because growing vegetation absorbs carbon dioxide and releases oxygen through the process of photosynthesis. Proposing to create tree plantations in an attempt to reduce levels of carbon in the atmosphere was, therefore, another example of the Goulburn Mulwaree Council showing a firm commitment to the principles of sustainable environmental management. See image 4

Although these additional initiatives raise many important questions for environmental management, and are highly relevant to discussions of sustainability, this case study will focus on the aspects of the Sustainable Cities Project which relate to sustainable waste and water management. Chapter Two will discuss the general perceptions of different stakeholders towards the issue of using recycled wastewater to augment (top up) drinking water supplies. Chapter Three will discuss the specific details of the project as well as the decision-making processes underpinning its implementation and Chapter Four will explore the implications that the 'Sustainable Cities Project' has for sustainability, social justice and equity.

Wastewater recycling

In the Sustainable Cities Project outline, it was indicated that the wastewater recycling plan would involve a process known as 'indirect potable reuse'. This means that sewage is treated in a plant, directed into a reclamation plant, and then discharged into an existing water source (such as a dam) to augment the water level. After treated wastewater is released into a dam it is treated once more before being consumed by humans, in the same manner that the water we ordinarily drink is treated. Using this sequence of purification processes ensures that the water being 'reused' (recycled) is 'potable' (drinkable). It is called 'indirect' potable reuse because it is indirectly added to drinking water supplies.

In a wastewater treatment plant, water is usually purified through a process known as 'reverse osmosis'. During this process water is pushed through a semi-permeable membrane. This membrane only allows water molecules to pass through it, meaning that any impurities (such as bacteria and any solid matter) are left behind.

Recent wastewater recycling proposals in Australia

Manly and Cronulla, New South Wales

Throughout many parts of Australia, wastewater is recycled and used for purposes other than human consumption. This practice is becoming more and more common, as local councils and governments are realising that existing systems of water use and waste disposal are unsustainable. In August 2006, the NSW State Government announced that two water recycling projects would soon be implemented in Sydney, one in Manly and the other in the Sutherland Shire. Under the new plan, treated sewage effluent, rather than being deposited into the ocean, would be reused to water parks and sporting greens in the two areas. It has been estimated that together these projects could save over 550 million litres of water each year.

Toowoomba, Queensland

In July 2006, a proposal to use recycled wastewater to augment town drinking water supplies was put to the residents of Toowoomba in Queensland. In a referendum which was held to determine whether or not the town would become the first in Australia to drink recycled wastewater, a little over 60 per cent of the electorate voted 'no'. The process has been proven safe and is used in other cities of the world, such as London and Singapore. In Singapore, the process of reverse osmosis (described above) is used as part of their 'NEWater' scheme, which uses recycled wastewater to supplement the city's drinking water.

The Goulburn Mulwaree Sustainable Cities Project is, in many ways, very similar to the proposal that was put to the residents of Toowoomba. In terms of the lack of water supplies and the options that were available to resolve this problem, the two towns have indeed faced a comparable situation. The processes of management underpinning the two proposals, however, have differed quite considerably. These different approaches reflect the varying approaches that can be taken to managing environmental issues and juggling the interests of different stakeholders.

In Toowoomba the decision over whether or not to recycle treated sewage effluent and incorporate this into drinking water supplies was determined via a referendum, whereas in Goulburn the Sustainable Cities Project proposal will involve a lengthy process of community consultation before a final decision is made. The implications these differing processes of management have for sustainability, social justice and equity are discussed further in Chapter Four.