The Infrastructure Cliff: Queensland’s Pending Wastewater Disaster
What is the Infrastructure Cliff?
The infrastructure cliff: The period when infrastructure reaches the end of its expected life cycle. This infrastructure requires replacement, refurbishment, or an alternative process to make the existing infrastructure redundant or function differently.
How does this infrastructure cliff relate to Queensland’s Wastewater?
Following World War II, there was a large acceleration in expanding the water and sewerage networks. From the 1960s — 1990s, approximately 22,000kms of pipes composed of asbestos cement (AC) were installed. This material continues to serve Queensland’s water and wastewater supply [2].
The material choice was prevalent in numerous countries including USA, UK, and Canada as no adverse health risks were associated with drinking water from these pipes. The issue arising from AC pipes is the material’s expected median life is 70 years. For pipes implemented in 1960, we are only 7 years from reaching its median life. This age is a median meaning some of the pipes already requires attention.
Projections show: As more units begin to fail, simply replacing the sewerage pipes is not an optimal solution.
So, what are the difficulties with replacing the pipes?
Difficulty 1 — Money
The financial implications with replacing the pipes are substantial. According to the Local Government Association of Queensland (LGAQ), the water and sewerage infrastructure is worth $37 billion, majority of which is the pipe network. It is safe to assume that it will be a costly investment, likely too costly to proceed with.
Difficulty 2 — Time
Another key predicament regarding the AC pipes is the time needed to replace them. 22,000kms, all of which lies underneath existing infrastructure including roads and buildings. The LGAQ predicts that the process could take over 170 years to replace at a rate of 0.3%. Most pipes would fail before being tended to, creating a catastrophe to the public.
Difficulty 3 — Attention
Referring to the LGAQ, there is another element further complicating the problem. Expansion. The government is continuing to spend on expanding the water and sewerage pipe network. Prioritising this (not saying that continuing to expand the network is a negative) can lead to the degradation of existing pipes not being easily noticed. Sometimes an ageing asset needs to show signs of slowing down to gain attention, potentially when it’s already too late.
Summary of Queensland’s Wastewater situation:
The need to address the infrastructure cliff:
The continual desire for sustainable development is imperative. To address and rectify the infrastructure cliff, it will ensure sustainable water and wastewater systems for the 370 communities that the infrastructure accommodates. The UN have outlined 17 different goals to strive for to achieve a sustainable community. Three of which strongly relate to this current issue.
6. Clean Water and Sanitation
9. Industry, Innovation, and Infrastructure
13. Climate Action
Fresh and clean water is essential to human life. With rainfall becoming a far less dependable water source, ensuring that all citizens have access to water without being dependent on rainfall should be self-explanatory.
AC pipes have no adverse effects on the water quality. The innovative choice of using Polyvinyl chloride (PVC) shares this characteristic, but also provides a more sustainable infrastructure for the water and wastewater industry. This change is highlighted in figure 3. [1]
How can we fix the infrastructure cliff?
There are four key options that have been considered by QWARP:
1 - Repairing the Existing Pipe
2 - Replacing Pipe with New Material
3 - Deferring Action for Minor Defects
4 - Relining the Interior of the Existing Pipe
The current solution in place focuses on the first two options, repair and replace. Predominantly because neglecting issues are short-term solutions, not long-term sustainable options. Additionally, relining is a cost-effective alternative to replacement but unfortunately cannot be implemented to every sewerage pipe.
How to optimally repair or replace the wastewater infrastructure.
4 Opportunities to Solve the Infrastructure Cliff
- More Knowledge
The key to achieving a sustainable model is to understand the characteristics of each individual AC pipe. With this understanding, we can better determine when pipes need attention, and what type of attention is necessary.
For a state-wide project, it is essential to know the status of every pipe. An emphasis on collecting and analysing data to improve our understanding of each pipes age, condition, redundancy, and vulnerability [3].
With this up-to-date and in-depth information, it will allow us to address specific areas of the sewerage network that require immediate attention. In addition, we can ascertain whether reparation or replacement is the more cost-effective strategy for a particular instance.
2. Alternative Methods — Same Outcome
Opposed to simply replacing the pipe networks, down-sizing, decentralisation, or use of emerging technologies should be considered. As mentioned prior, there are 22,000kms of pipes. If an opportunity arises for the distance to be reduced, it will not only provide a more efficient wastewater infrastructure model, but also reduce the cost of the overall project.
Many of the existing networks are necessary for water and wastewater transportation. However, opportunities to downsize or decentralise are present. When mentioning “attention” as an earlier issue, paying too much attention could also be an issue. A narrow-minded approach of simply amending the current infrastructure would miss an innovative chance to potentially help solve the infrastructure cliff.
3. Productivity
Increase in the productivity of the process of replacing and repairing will allow more pipes to be diagnosed and treated before failing. This can be achieved by recognising and analysing past performance, to put in more efficient systems.
4. Only replace when necessary
Increasing the focus of repairing the current infrastructure, opposed to simply replacing them is the key to addressing the infrastructure cliff. With an improved understanding of the pipe's characteristics, we can determine whether maintenance of the pipe segment is more cost-efficient than replacing the unit entirely.
If replacement was optimistically increased from 0.3% to 1.0%, 420kms of pipes being replaced annually would still cost $114.7 million. Additionally, the pipes would still need to be in service for 100 years to allow for effective replacement, exceeding the 70-year median of AC pipes. This extremely high cost of replacement highlights the importance to perform simple repairs and to only replace when necessary.
This is a simplified summary, if you are interested in further details I highly recommend reading:
Fearon, R., & Cosgrove, R. (2019). Infrastructure Cliff? Queensland’s Ageing Water and Sewerage Assets. 2. Cost implications for in-ground assets. Queensland Water Regional Alliance Program.
What risks are involved with this process?
Inevitably, this is not a simple fix. It provides me with more confidence that processes are being implemented now, changing the infrastructure management from a reactive approach to a proactive one. The above solution will provide a cost-effective, collaborative, and systematic method to address the AC pipes in the most critical condition.
At any particular time, an innovative advance in the industry may become the best option, which is why continual data collection and analysis is essential. The big questions are, have we left it too late? Is there a better way to go about this?
References
[1] New report reveals how infrastructure defines our climate. (n.d.). UN Environment. https://www.unep.org/news-and-stories/press-release/new-report-reveals-how-infrastructure-defines-our-climate
[2] Local Government Association of Queensland. (n.d.). The infrastructure cliff — LGAQ. LGAQ. https://www.lgaq.asn.au/news/article/866/the-infrastructure-clif
[3] Fearon, R., & Cosgrove, R. (2019). Infrastructure Cliff? Queensland’s Ageing Water and Sewerage Assets. 2. Cost implications for in-ground assets. Queensland Water Regional Alliance Program.
The infrastructure cliff: The period when the infrastructure in question reaches the end of its expected life cycle. This infrastructure requires replacement, refurbishment, or an alternative process is put in place to make it redundant or functional.
