Bushfires threaten drinking water safety. The consequences could last for decades



Warnings about poor drinking water quality are in place in some areas affected by the bushfires.
From shutterstock.com

Stuart Khan, UNSW

Bushfires pose serious short- and long-term impacts to public drinking water quality. They can damage water supply infrastructure and water catchments, impeding the treatment processes that normally make our water safe to drink.

Several areas in New South Wales and Victoria have already been issued with warnings about the quality of their drinking water.

Here’s what we know about the short- and long-term risks.




Read more:
How to monitor the bushfires raging across Australia


Short-term risks

Bushfires can damage or disrupt water supply infrastructure as they burn. And the risks can persist after the fires are out.

A loss of power, for example, disables important water treatment processes such as chlorine disinfection, needed to kill microorganisms and make our water safe to drink.

Drinking water for the towns of Eden and Boydtown on the NSW south coast has been affected in this way over recent days. Residents have been advised to boil their water before drinking it and using it for cooking, teeth brushing, and so on.

Other towns including Cobargo and Bermagui received similar warnings on New Year’s Eve.




Read more:
Disaster recovery from Australia’s fires will be a marathon, not a sprint


In some cases, untreated water, straight from a river supply, may be fed directly into drinking water systems. Water treatment plants are bypassed completely, due to damage, power loss, or an inability to keep pace with high volumes of water required for firefighting.

We’ve seen this in a number of southern NSW towns this week including Batlow, Adelong, Tumbarumba, and the southern region of Eurobodalla Council, stretching from Moruya to Tilba. Residents of these areas have also been urged to boil their drinking water.

Untreated river water, or river water which has not been properly disinfected with chlorine, is usually not safe for drinking in Australia. Various types of bacteria, as well as the parasites giardia and cryptosporidium, could be in such water.

Animals including cattle, birds and kangaroos can excrete these microorganisms into river water. Septic tanks and sewage treatment plants may also discharge effluents into waterways, adding harmful microorganisms.

Human infection with these microorganisms can cause a range of illnesses, including gastrointestinal diseases with symptoms of diarrhoea and vomiting.




Read more:
What are parasites and how do they make us sick?


Long-term risks

Bushfires can damage drinking water catchments, which can lead to longer term threats to drinking water. Drinking water catchments are typically forested areas, and so are vulnerable to bushfire damage.

Severe impacts to waterways may not occur until after intense rainfall. Heavy rain can wash ash and eroded soil from the fires into waterways, affecting drinking water supplies downstream.

For example, bushfire ash contains nutrients, such as nitrogen and phosphorous. Increased nutrient concentrations can stimulate the growth of cyanobacteria, commonly known as “blue-green algae”.

Cyanobacteria produce chemicals which may cause a range of water quality problems, including poor taste and odour. Some cyanobacteria can produce toxic chemicals, requiring very careful management to protect treated drinking water.

Boiling water will kill microorganisms, but not chemical substances.
From shutterstock.com

Many water treatment plants include filtration processes to filter small suspended particles from the water. But an increase in suspended particles, like that which we see after bushfires, would challenge most filtration plants. The suspended particles would be removed, but they would clog the filters, requiring them to be more frequently pulled from normal operation and cleaned.

This cleaning, or backwashing, is a normal part of the treatment process. But if more time must be spent backwashing, that’s less time the filters are working to produce drinking water. And if the rate of drinking water filtration is slowed and fails to keep pace with demand, authorities may place limitations on water use.




Read more:
The bushfires are horrendous, but expect cyclones, floods and heatwaves too


Boiling water isn’t always enough

In order to reduce the risk of gastrointestinal and other illnesses, water suppliers and health departments may issue a boil water alert, as we’ve seen in the past week. Bringing water to a “rolling boil” can reliably kill most of the microorganisms of concern.

In cases where water may be contaminated with chemical substances rather than microorganisms, boiling is usually not effective. So where there’s a risk of chemical contamination, public health messages are usually “do not drink tap water”. This means bottled water only.

Such “do not drink” alerts were issued this week following bushfire impacts to water treatment plants supplying the Victorian towns of Buchan and Omeo.




Read more:
How does poor air quality from bushfire smoke affect our health?


Impacts to catchments from bushfires and subsequent erosion can have long-lasting effects, potentially worsening untreated drinking water quality for many years, even decades.

Following these bushfires, many water treatment plant operators and catchment managers will need to adapt to changed conditions and brace for more extreme weather events in the future.The Conversation

Stuart Khan, Professor of Civil & Environmental Engineering, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sustainable shopping: tap water is best, but what bottle should you drink it from?



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The greenest option might be to get a disposable bottle but never dispose of it.
Shutterstock.com

Trevor Thornton, Deakin University and Simon Lockrey, RMIT University

Shopping can be confusing at the best of times, and trying to find environmentally friendly options makes it even more difficult. Our Sustainable Shopping series asks experts to provide easy eco-friendly guides to purchases big and small. Send us your suggestions for future articles here.


We have many options when it comes to how we drink water, given the large range of consumer products available, and Australia’s high standards of tap water.

But which option is the smartest choice from an environmental perspective?

According to the waste management hierarchy, the best option is one that avoids waste altogether. Recyclable options are less preferable, and landfill disposal the worst of all.

For water bottles, this suggests that keeping and reusing the same bottle is always best. It’s certainly preferable to single-use bottles, even if these are recyclable.




Read more:
Recycling can be confusing, but it’s getting simpler


Of course, it’s hardly revolutionary to point out that single-use plastic bottles are a bad way to drink water on environmental grounds. Ditching bottled water in favour of tap water is a very straightforward decision.

However, choosing what reusable bottle to drink it out of is a far more complex question. This requires us to consider the whole “life cycle” of the bottle.

Cycle of life

Life-cycle assessment is a method that aims to identify all of the potential environmental impacts of a product, from manufacture, to use, to disposal.

A 2012 Italian life-cycle study confirmed that reusable glass or plastic bottles are usually more eco-friendly than single-use PET plastic bottles.

However, it also found that heavy glass bottles have higher environmental impacts than single-use PET bottles if the distance to refill them was more than 150km.

Granted, you’re unlikely ever to find yourself more than 150km from the nearest drinking tap. But this highlights the importance of considering how a product will be used, as well as what it is made of.

What are the reusable options?

Metal bottles are among the most durable, but also require lots of resources to make.
Flickr CC

In 2011, we investigated and compared the life cycles of typical aluminium, steel and polypropylene plastic reusable bottles.

Steel and aluminium options shared the highest environmental impacts from materials and production, due to material and production intensity, combined with the higher mass of the metal bottles, for the same number of uses among the options. The polypropylene bottle performed the best.

Polypropylene bottles are also arguably better suited to our lifestyles. They are lighter and more flexible than glass or metal, making them easier to take to the gym, the office, or out and about.

The flip side of this, however, is that metal and glass bottles may be more robust and last longer, so their impacts may be diluted with prolonged use – as long as you don’t lose them or replace them too soon.

Health considerations are an important factor for many people too, especially in light of new research about the presence of plastic particles in drinking water.

Other considerations aside, is may even be best to simply buy a single-use PET plastic water bottle and then reuse it a bunch of times. They are lighter than most purpose-designed reusable bottles, but still long-lasting. And when they do come to the end of their useful life, they are more easily recycled than many other types of plastic.

Sure, you won’t look very aspirational, but depending on how many uses you get (as you approach the same number of uses as other options), you could be doing your bit for the environment.

Maintaining reusable options

There are a few things to bear in mind to ensure that reusable bottles produce as little waste as possible.

  1. Refill from the tap, as opposed to using water coolers or other bottled water that can come from many kilometres away, requiring packaging and distribution. Unsurprisingly, tap water has the lowest environmental impacts of all the options.

  2. Clean your bottle thoroughly, to keep it hygienic for longer and avoid having to replace grotty bottles. While cleaning does add to the environmental impact, this effect is minor in comparison to the material impacts of buying new bottles – as we have confirmed in the case of reusable coffee cups.




Read more:
Sustainable shopping: how to stop your bathers flooding the oceans with plastic


The verdict

To reduce your environmental impacts of a drink of water, reusing a bottle, whether a designer bottle or a single-use bottle you use time and again, makes the most sense from a life-cycle, waste and litter perspective.

The maintenance of your reusable container is also key, to make sure you get as many uses as you can out of it, even if you create minor additional environmental impacts to do so.

The ConversationUltimately, drinking directly from a tap or water fountain is an even better shout, if you have that option. Apart from the benefit of staying hydrated, you will reduce your impacts on our planet.

Trevor Thornton, Lecturer, School of Life and Environmental Sciences, Deakin University and Simon Lockrey, Research Fellow, RMIT University

This article was originally published on The Conversation. Read the original article.

More of us are drinking recycled sewage water than most people realise



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The Hawkesbury’s waters look beautifully natural but treated sewage makes up to 20% of the river flow where the North Richmond Filtration Plant draws its water.
Karl Baron/flickr, CC BY

Ian Wright, Western Sydney University

The world is watching as Cape Town’s water crisis approaches “Day Zero”. Questions are being asked about which other cities could be at risk and what can they do to avoid running dry. In Perth, Australia’s most water-stressed capital, it has been announced that the city is considering reusing all of its sewage as part of its future water supply.




Read more:
Cape Town is almost out of water. Could Australian cities suffer the same fate?


Drinking recycled sewage is a very confronting topic. But what many people don’t realise is that we already rely on recycled sewage in many Australian water supplies. Even in Australia’s biggest city, Sydney, it is an important part of the water supply. This is because many large towns discharge their treated sewage into the catchment rivers that supply the city.

But Perth is now looking to recycle all of its treated sewage. At the time of writing, the city’s water storages were at a low 35.3%. Cape Town’s reserves, by comparison, are at a critical low of 23.5% – but Perth was close to that point just a year ago when it was down to 24.8%.

Perth has been progressively “drought-proofing” itself by diversifying the city water supply. River flow and storage in dams accounts for only 10% of this supply. Desalination and groundwater extraction provide about 90% of the city’s supply. Only about 10% of Perth’s sewage is recycled, through advanced treatment and replenishment into its groundwater supplies.




Read more:
Is Perth really running out of water? Well, yes and no


Justifiably, many people have concerns about drinking recycled sewage. This reflects long-standing concern about hazards of contaminated water. An example is the devastating waterborne disease of cholera, which claims the lives of more than 100,000 people a year. Cholera is rare in many countries, but is endemic in waters across Africa and much of Southeast Asia.

As wastewater treatment technologies improve and urban populations grow, however, interest in using treated sewage in drinking water supplies has been increasing. No Australian urban water supply currently uses “direct potable reuse” of treated sewage, but the concept is being seriously considered.




Read more:
This is what Australia’s growing cities need to do to avoid running dry


So how is treated sewage being indirectly reused?

There is, however, indirect reuse when water is drawn from rivers into which recycled sewage is discharged upstream. For instance, the catchment of Sydney’s giant Warragamba Dam has a population of about 116,000 people. This includes the large settlements of Goulburn, Lithgow, Moss Vale, Mittagong and Bowral. These communities discharge their treated sewage into the catchment rivers.

Several large towns discharge treated sewage into rivers supplying Warragamba Dam, which holds 80% of Sydney’s water reserves.
popejon2/flickr, CC BY-NC-ND

The New South Wales Environment Protection Authority regulates these discharges, which form a small part of the total annual catchment inflow to the dam. Such recycling of sewage is termed “indirect potable reuse”.

Residents in some parts of northwestern Sydney also drink water that is partly supplied by another form of indirect reuse of treated sewage. The North Richmond Water Filtration Plant extracts and treats water drawn directly from the Hawkesbury-Nepean River. A major contributor to the river flow is treated sewage discharged from upstream treatment plants.

These include plants in the Blue Mountains (Winmalee), St Marys, Penrith, Wallacia, and West Camden. The largest individual discharge of treated sewage to the river in recent weeks is from St Marys Advanced Water Recycling Plant, one of the biggest in Australia. This plant uses advanced membrane technology to produce highly treated effluent before it is discharged into the river.

St
Marys Advanced Water Recycling Plant, one of the biggest in Australia, treats sewage and discharges the water into the Hawkesbury-Nepean River.

Ian Wright, Author provided

Available data are limited, but in the very low river flows in the recent dry summer I estimate that treated sewage comprised almost 32% of the Hawkesbury-Nepean flow in the North Richmond area for the first week of January. The water is highly treated at the Sydney Water-owned North Richmond plant to ensure it meets Australian drinking water guidelines.

Every year the river receives more and more treated sewage as a result of population growth. This is certain to continue, as Greater Sydney is forecast to gain another 1.74 million residents in the next 18 years. Much of this growth will be in Western Sydney, one of the most rapidly growing urban centres in Australia. This will result in more treated sewage, and urban runoff, contributing to the Hawkesbury-Nepean River flow.




Read more:
As drought looms again, Australians are ready to embrace recycled water


Paying for desalination while water goes to waste

However, most of Sydney’s sewage is not recycled at all. Three massive coastal treatment plants (at North Head, Bondi and Malabar) serve the majority of Sydney’s population. These three plants discharge nearly 1,000 million litres (1,000ML) of primary treated sewage into the ocean every day. That is roughly an Olympic pool of sewage dumped in the ocean every four minutes!

Perhaps if Sydney was as chronically short of water as Perth there would be plans to recycle more of its sewage. Instead, Sydney has adopted desalination as a “new” source of drinking water, rather than treating larger volumes of sewage for any form of potable reuse.

Sydney’s desalination plant sits idle about 10 kilometres south of the Malabar treatment plant. It has a capacity for supplying 250ML a day. Even though it isn’t supplying water now, it is very expensive. In 2017, the privately owned plant, sitting on standby, charged Sydney Water A$194 million.

Only when Sydney’s storages fall below the trigger of 60% will the plant supply drinking water. With storages at 76.5%, the plant will not operate for a while.


The Conversation


Read more:
The role of water in Australia’s uncertain future


Ian Wright, Senior Lecturer in Environmental Science, Western Sydney University

This article was originally published on The Conversation. Read the original article.

Some remote Australian communities have drinking water for only nine hours a day



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Communities in Cape York are among those with restricted access to mains water.
NomadicPics/Flickr, CC BY-SA

Cara Beal, Griffith University

Some remote Australian communities have access to drinking water for only nine hours a day for part of the year, but these households can still use up to ten times the average of urban households.

Many communities in the Torres Strait Islands have their mains water supply limited to nine hours a day during the week, and 16 hours a day at weekends, during the six-month dry season from May to October. Some remote Aboriginal communities in mainland Australia have similar restrictions.


Read more: Water in northern Australia: a history of Aboriginal exclusion


The vast majority of these residents do not pay directly for water, as they live in public housing. A three-year research project has been using smart meters to monitor water use as well as promoting community discussion. We found the water is largely used for things that might be viewed as luxuries in an urban setting but which play an important role in community life, such as dampening roofs for cooling and washing fishing gear.

The challenge, therefore, is finding ways to manage this unsustainable water use, apart from physically turning off the water. By understanding the challenges of life in remote Australia and working closely with locals, we identified some reasonable and realistic ways to reduce water use.

Revealing the reasons for high water use

Water restrictions, which have been in place on and off since the early 2000s, exist for a simple reason: there is not enough water to meet demand, especially during the dry season.

Providing water to remote and isolated communities is expensive, whether it comes from a desalination plant (which turns seawater into drinking water) or from a groundwater bore. Typically a diesel generator is used to generate power for water extraction, treatment, pumping and sewage management.

Leaking taps contribute to high water use in some remote communities.
Cara Beal, Author provided

For the past three years I have led a team of Griffith University researchers investigating how water was being used, and how it could be reduced. We installed smart meters in three remote communities, across the Torres Strait Islands, Cape York and the Northern Territory.

The data revealed an average daily use of 900 litres per person, rising to more than 4,000L per person per day in some cases. (The average southeast Queensland household daily use is around 180L per person.) Once the energy costs of pumping and treating this water via diesel-fuelled generators are included, it’s clear this is unsustainable.

We then broke down household water use into categories such as showering and outdoor, and discussed water use habits with each participating household. This gave unprecedented insights into how, where and why water is being used in remote community households.

Beating the dust and heat

Outdoor water use makes up, on average, at least 75% of total household water demand. This can get even higher in the dry season. Leaking taps are also a major contributor.

Average residential water use per person in three remote communities from Far North Queensland and the Northern Territory.
Cara Beal, Author provided

We spoke to participants in Cape York and the Torres Strait about their water use during the middle of the dry season. We found five key drivers for this high outdoor water use (aside from leaks):

  • dust control (and flea control) from non-surfaced roads and yards
  • cooling down (watering the house roof and bare earth or concrete driveways to create an evaporative effect)
  • washing down boats and fishing or hunting equipment
  • physical amenity (gardening or greening)
  • social amenity (having a continuous source of tap water was an important resource during social gatherings, including sorry camps, tombstone openings, cultural events and extended family gatherings).

Reducing drivers of high water use

In urban areas, outdoor household water use is often described as “discretionary”. This implies that the water is associated with “wants” (like car washing, irrigation or filling pools) more than “needs” (drinking, cooking or personal hygiene).

But in the case of these remote communities, our research suggests that outdoor water use is often linked directly to health and well-being. In areas where temperatures during winter regularly climb above 30℃, dust suppression, cooling and flea control are not trivial desires.

Water is used for controlling dust from unsealed roads and bare earth in remote communities.
Cara Beal, Author provided

This means that simply adopting the typical urban water management approach is unlikely to reduce demand. Poor sanitation in many Indigenous communities further complicates the situation.


Read more: It’s a fallacy that all Australians have access to clean water, sanitation and hygiene


The challenge is to reduce water demand, to allow restrictions to be eased in the future, while maintaining a sustainable level of water use in these communities.

Community-involved solutions

We asked our participants from two communities in western Cape York and the Torres Strait Islands how they would reduce high outdoor water use.

Overwhelmingly, they observed a need for more education and awareness of why water conservation is important. Before piped water systems, people were deeply connected to their water sources and could self-manage their supplies.

Nowadays many communities have only one or two good-quality water sources, and the Western-style built infrastructure acts as a barrier to this previous personal connection to water. The economic value of water is also poorly understood in many remote communities.

Similarly, service providers (and others) need to develop a greater understanding of the cultural, social and spiritual value of water from an Aboriginal and Torres Strait Island person’s perspective.


Read more: The role of water in Australia’s uncertain future


Our team, together with the participants and local service providers, trialled a water efficiency pilot program. This involved both residents and local councils learning about the importance of conserving water and offering suggestions on ways to do this. Talking with the residents, it become clear that high outdoor water use was not purely driven by the fact that water is free for them.

Many of the activities were centred on health (cooling and dust suppression) and food provision (fishing and hunting). Nevertheless, ways of reducing water use were identified. These included watering after dark, reporting leaks, using tap timers and washing hunting and fishing equipment on grass.

The ConversationThe pilot programs have shown promising results, although their funding will shortly end. The challenge will be to change behaviour over time. If this can be done, it will go a long way to reducing the need to limit some communities to nine hours of treated water a day.

Cara Beal, Senior research fellow, Griffith University

This article was originally published on The Conversation. Read the original article.