When water is scarce, we can’t afford to neglect the alternatives to desalination


Ian Wright, Western Sydney University and Jason Reynolds, Western Sydney University

This is the second of two articles looking at the increasing reliance of Australian cities on desalination plants to supply drinking water, with less emphasis on the alternatives of water recycling and demand management. So what is the best way forward to achieve urban water security?


An important lesson from the Millennium Drought in Australia was the power of individuals to curb their own water use. This was achieved through public education campaigns and water restrictions. It was a popular topic in the media and in daily conversations before the focus turned to desalination for water security.

Water authorities were also expanding the use of treated wastewater – often a polite term for sewage – for “non-potable” uses. These included flushing toilets, watering gardens, and washing cars and laundry.

Today, the emphasis on recycling wastewater in some locations is declining. The arguments for increased water recycling appear to be falling away now that desalinated water is available.




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This trend ignores the fact that the potential supply of recycled water increases as populations grow.

Today most Australian wastewater is treated then disposed into local streams, rivers, estuaries and the ocean. In Sydney, for example, the city’s big three outfalls dump nearly 1 billion litres (1,000 megalitres, ML) a day into the ocean.

Where has recycling succeeded?

Australia has several highly successful water recycling projects.

Sydney introduced the Rouse Hill recycled water scheme in 2001. Highly treated wastewater is piped into 32,000 suburban properties in distinct purple pipes. Each property also has the normal “potable” drinking water supply.

Rouse Hill is considered a world-leading urban recycling scheme. South Australia (Mawsons Lakes) and Victoria (Yarra Valley Water, South East Water) have similar projects.

Our farmers often struggle to secure water for irrigation. Chronic water shortages across the Murray-Darling river system vividly demonstrate this.




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Recycled water can play an important role in agricultural schemes. There are successful examples in South Australia (Virginia Irrigation Scheme), Victoria (Werribee) and New South Wales (Picton).




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Perth has gone further by embracing water recycling for urban use with plans to treat it to a drinking water standard. Part of the extensive treatment process involves reverse osmosis, which is also used in desalination. The treated water is then pumped into groundwater aquifersand stored.

This “groundwater replenishment” adds to the groundwater that contributes about half of the city’s water supply. The Water Corporation of Perth has a long-term aim to recycle 30% of its wastewater.

Southeast Queensland, too, has developed an extensive recycled water system. The Western Corridor Recycled Water Scheme also uses reverse osmosis and can supplement drinking water supplies during droughts.




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Demand management works too

Past campaigns to get people to reduce water use achieved significant results.

In Sydney, water use fell steeply under water restrictions (2003-2009). Since the restrictions have ended, consumption has increased under the softer “water wise rules”. Regional centres including (Tamworth) outside of Sydney are under significant water restrictions currently with limited relief in sight.

Despite a 25% increase in Sydney’s population, total demand for drinking water remains lower than before mandatory restrictions were introduced in late 2003.
© Sydney Water, used with permission

The Victorian government appears to be the Australian leader in encouraging urban water conservation. Across Melbourne water use per person averaged 161 litres a day over 2016-18. Victoria’s “Target 155” program, first launched in late 2008 and revived in 2016, aims for average use of 155 litres a day.

In a comparison of mainland capitals Melbourne used the least water per residential property, 25% less than the average. Southeast Queensland residents had the second-lowest use, followed by Adelaide. Sydney, Perth and Darwin had the highest use.

Although Melbourne water prices are among the highest of the major cities, lower annual water use meant the city’s households had the lowest water bills in 2016-17, analysis by the Australian Bureau of Meteorology found.


Calculated from Bureau of Meteorology data, Author provided

What impact do water prices have?

Clearly, water pricing can be an effective tool to get people to reduce demand. This could partly explain why water use is lower in some cities.

Water bills have several components. Domestic customers pay a service fee to be connected. They then pay for the volume of water they use, plus wastewater charges on top of that. Depending on where you live, you might be charged a flat rate, or a rate that increases as you use more water.

The chart below shows the pricing range in our major cities.


https://datawrapper.dwcdn.net/xIJQR/3/


Flat charges for water per kilolitre (where a kL equals 1,000 litres) apply in Sydney ($2.08/kL)), Darwin ($1.95/kL) and Hobart ($1.06/kL.

However, most water authorities charge low water users a cheaper rate, and increased prices apply for higher consumption. The most expensive water in Australia is for Canberra residents – $4.88 for each kL customers use over 50kL per quarter. The cheapest water is Hobart ($1.06/kL).

Higher fees for higher residential consumption are charged in Canberra, Perth, Southeast Queensland, across South Australia and in Melbourne. In effect, most major water providers penalise high-water-using customers. This creates an incentive to use less.

For example, Yarra Valley Water customers in Melbourne using less than 440 litres a day pay $2.64/kL. From 441-880L/day they are charged $3.11/kL. For more than 881L/day they pay $4.62/kL – 75% more than the lowest rate.

Is recycled water getting priced out of business?

Recycling water may not be viable for Sydney Water. It can cost over $5 per 1kL to produce, but the state pricing regulator, IPART, sets the cost of recycled water to Sydney customers at just under $2 per kL. That’s probably well below the cost of production.

Recycled water, where available, is a little bit more expensive ($2.12/kL) in South Australia.

Subsidies are probably essential for future large recycling schemes. This was the case for a 2017 plan to expand the Virginia Irrigation Scheme. South Australia sought 30% of the capital funding from the Commonwealth.

Where to from here?

Much of southern Australia is facing increasing water stress and capital city water supplies are falling. Expensive desalination plants are gearing up to supply more water. Will they insulate urban residents from the disruption many others are feeling in drought-affected inland and regional locations? Should we be increasing the capacity of our desalination plants?

We recommend that urban Australia should make further use of recycled water. This will also reduce the environmental impact of disposing wastewater in our rivers, estuaries and ocean. All new developments should have recycled water made available, saving our precious potable water for human consumption.

Water conservation should be given the highest priority. Pricing of water that encourages recycling and water conservation should be a national priority.




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


You can read the first article, on cities’ increasing reliance on desalination, here.The Conversation

Ian Wright, Senior Lecturer in Environmental Science, Western Sydney University and Jason Reynolds, Research Lecturer in Geochemistry, Western Sydney University

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

Your asthma puffer is probably contributing to climate change, but there’s a better alternative



File 20180305 146655 1azvp4m.jpg?ixlib=rb 1.1
There is an environmentally friendly option.
from http://www.shutterstock.com

Brett Montgomery, University of Western Australia

I breathe all the way out. There’s a quiet puff of gas from my inhaler, and I breathe all the way in. I hold my breath for a few seconds and the medicine is where it needs to be: in my lungs.

Many readers with asthma or other lung disease will recognise this ritual. But I suspect few will connect it with climate change. Until recently, neither did I.

In asthma, there is narrowing of the airways that carry air into and out of our lungs. The lining of the airways becomes swollen, muscles around the airways contract, and mucus is produced. All these changes make it hard to breathe out.

The most commonly used medicines in asthma are delivered by inhalation. Inhaling gets the medicines straight to the airways, speeding and maximising their local effects, and minimising side effects elsewhere compared to, say, swallowing tablets.

Some medicines (“relievers”) work quickly to relax the airway muscles. Others (“preventers”) work more slowly but do more good, preventing asthma’s swelling and inflammation of the airways.




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These medicines are available in various sorts of inhaler devices. The devices fall into two broad types: “metered dose inhalers” and “dry powder inhalers” of various shapes and sizes.

In metered dose inhalers, the medicine and a pressurised propellant liquid are mixed together in a little canister, and then sprayed out of the inhaler in a measured puff of fine mist. This is inhaled, often after passing through a “spacer” which allows more of the medicine to reach the lungs. While the medicine is absorbed by the body, the propellant, now a gas, is exhaled unchanged.

In dry powder inhalers, the medicine is in the form of a fine powder which is swept into the lungs as the user breathes in — there is no spray and no spacer.

Powder inhalers don’t release any gases at all.
Author provided

It’s feasible for many (but not all) people to use either sort of device. Young children do better with metered dose inhalers and spacers, as do people who struggle to inhale. But most asthmatics can inhale well from dry powder inhalers.

The two types of inhaler seem to work just as well as each other; if anything the dry powder ones might be a little better.

Metered dose inhalers are more often prescribed than dry powder devices in many countries, but this has more to do with history and familiarity than effectiveness.

What about those gases?

You might remember hearing, years ago, about “CFCs” — chlorofluorocarbons — and their dire effect on the ozone layer. A successful international treaty, the Montreal Protocol, led to their phase-out from various uses, including medical inhalers. And with that, I thought, the environmental problems of inhaler gases had ended.




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But CFCs were replaced with “HFCs” — hydrofluorocarbons — which are safe for the ozone layer, but which are potent global warming gases. HFCs are better known in their role as refrigerant gases in air conditioners and refrigerators.

A recent amendment to the Montreal Protocol has now planned a phase-out of HFCs, too, but it’s slow, with deadlines decades away. Earlier prudent management of these gases could make a big difference to climate change.

The one most often found in asthma metered dose inhalers, norflurane, is 1,430 times more potent than the best-known warming culprit, carbon dioxide. Another, apaflurane, is 3,220 times more potent than carbon dioxide.

Such warming power explains why even the small amounts in an inhaler are significant. Globally, tens of millions of tons of carbon dioxide equivalent are attributable annually to these inhaler gases.

How much pollution are inhaler gases responsible for in Australia? I wrote to several companies marketing asthma inhalers in Australia, asking them how much of these gases are present in their products. Some gave straight answers, but some hedged on grounds of commercial confidentiality. This makes it hard for me to be exact.

But based on some reasonable assumptions, and multiplying these by the number of inhalers dispensed on our Pharmaceutical Benefits Scheme last year, I tallied nearly 116,000 tonnes of carbon dioxide-equivalent pollution.

That’s equivalent to the emissions of about 25,000 cars annually. And this is surely an underestimate, as it doesn’t account for reliever inhalers sold over the counter. A person using a preventer inhaler monthly, plus the odd reliever inhaler, could easily release the annual equivalent of a quarter of a ton of carbon dioxide — that’s like burning 100 litres of petrol.




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How to change

The good news is, for many people with asthma, there’s an easy solution: shifting from metered dose inhalers to dry powder inhalers. As above, this won’t suit everyone, but will be possible for many.

I am both a doctor and a person with asthma. As an asthmatic, I’ve found changing inhalers to be easy — if anything, my dry powder inhalers are simpler to use. And as a doctor, I’ve been pleasantly surprised by how open my patients have been to this topic. I worried people might find it weird their GP was raising environmental issues at their appointment, but my fears were unfounded.

If you have asthma, a chat with your doctor or pharmacist would be a good way to gauge whether a dry powder inhaler is feasible for you. Don’t be surprised if they haven’t heard of this gas issue — awareness still seems limited.

The ConversationIf metered dose inhalers are a better choice for you, please don’t panic or quit your medicines. These gases probably won’t be the biggest contributor to your personal carbon footprint. Asthma control is really important, and these medicines work really well. But consider changing if it’s an option for you — when it comes to reducing our footprint, every little bit counts.

Brett Montgomery, Senior Lecturer in General Practice, University of Western Australia

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