5 ways fungi could change the world, from cleaning water to breaking down plastics

Mitchell P. Jones, Vienna University of TechnologyFungi — a scientific goldmine? Well, that’s what a review published today in the journal Trends in Biotechnology indicates. You may think mushrooms are a long chalk from the caped crusaders of sustainability. But think again.

Many of us have heard of fungi’s role in creating more sustainable leather substitutes. Amadou vegan leather crafted from fungal-fruiting bodies has been around for some 5,000 years.

More recently, mycelium leather substitutes have taken the stage. These are produced from the root-like structure mycelium, which snakes through dead wood or soil beneath mushrooms.

You might even know about how fungi help us make many fermented food and drinks such as beer, wine, bread, soy sauce and tempeh. Many popular vegan protein products, including Quorn, are just flavoured masses of fungal mycelium.

But what makes fungi so versatile? And what else can they do?

Show me foamy and flexible

Fungal growth offers a cheap, simple and environmentally friendly way to bind agricultural byproducts (such as rice hulls, wheat straw, sugarcane bagasse and molasses) into biodegradable and carbon-neutral foams.

Fungal foams are becoming increasingly popular as sustainable packaging materials; IKEA is one company that has indicated a commitment to using them.

Fungal foams can also be used in the construction industry for insulation, flooring and panelling. Research has revealed them to be strong competitors against commercial materials in terms of having effective sound and heat insulation properties.

Rigid and flexible fungal foams have several construction applications including (a) particle board and insulation cores, (b) acoustic absorbers, (c) flexible foams and (d) flooring.
Jones et al

Moreover, adding in industrial wastes such as glass fines (crushed glass bits) in these foams can improve their fire resistance.

And isolating only the mycelium can produce a more flexible and spongy foam suitable for products such as facial sponges, artificial skin, ink and dye carriers, shoe insoles, lightweight insulation lofts, cushioning, soft furnishings and textiles.

Paper that doesn’t come from trees? No, chitin

For other products, it’s the composition of fungi that matters. Fungal filaments contain chitin: a remarkable polymer also found in crab shells and insect exoskeletons.

Chitin has a fibrous structure, similar to cellulose in wood. This means fungal fibre can be processed into sheets the same way paper is made.

When stretched, fungal papers are stronger than many plastics and not much weaker than some steels of the same thickness. We’ve yet to test its properties when subject to different forces.

Fungal paper’s strength can be substituted for rubbery flexibility by using specific fungal species, or a different part of the mushroom. The paper’s transparency can be customised in the same way.

Paper sheets with varying transparency derived from the brown crab’s shell *(C. pagurus)* (column 1), fungi *Daedaleopsis confragosa* (column 2) and the mushroom *Agaricus bisporus* (column 6). Columns 3, 4 and 5 show fungal papers of varying transparencies based on mixtures of the two species.
Wan Nawawi et al

Growing fungi in mineral-rich environments results in inherent fire resistance for the fungus, as it absorbs the inflammable minerals, incorporating them into its structure. Add to this that water doesn’t wet fungal surfaces, but rolls off, and you’ve got yourself some pretty useful paper.

A clear solution to dirty water

Some might ask: what’s the point of fungal paper when we already get paper from wood? That’s where the other interesting attributes of chitin come into play — or more specifically, the attributes of its derivative, chitosan.

Chitosan is chitin that has been chemically modified through exposure to an acid or alkali. This means with a few simple steps, fungal paper can adopt a whole new range of applications.

For instance, chitosan is electrically charged and can be used to attract heavy metal ions. So what happens if you couple it with a mycelium filament network that is intricate enough to prevent solids, bacteria and even viruses (which are much smaller than bacteria) from passing through?

White-button mushroom — Fungal chitin paper derived from white-button mushrooms is an eco-friendly alternative to standard filter materials.
Shutterstock

The result is an environmentally friendly membrane with impressive water purification properties. In our research, my colleagues and I found this material to be stable, simple to make and useful for laboratory filtration.

While the technology hasn’t yet been commercialised, it holds particular promise for reducing the environmental impact of synthetic filtration materials, and providing safer drinking water where it’s not available.

Mushrooms in modern medicine

Perhaps even more interesting is chitosan’s considerable biomedical potential. Fungal materials have been used to create dressings with active wound healing properties.

Although not currently on the market, these have been proven to have antibacterial properties, stem bleeding and support cell proliferation and attachment.

Fungal enzymes can also be used to combat bacteria active in tooth decay, enhance bleaching and destroy compounds responsible for bad breath.

Then there’s the well-known role of fungi in antibiotics. Penicillin, made from the Penicillium fungi, was a scientific breakthrough that has saved millions of lives and become a staple of modern healthcare.

Many antibiotics are still produced from fungi or soil bacteria. And in an age of increasing antibiotic resistance, genome sequencing is finally enabling us to identify fungi’s untapped potential for manufacturing the antibiotics of the future.

Mushrooms mending the environment

Fungi could play a huge role in sustainability by remedying existing environmental damage.

For example, they can help clean up contaminated industrial sites through a popular technique known as mycoremediation, and can break down or absorb oils, pollutants, toxins, dyes and heavy metals.

They can also compost some synthetic plastics, such as polyurethane. In this process, the plastic is buried in regulated soil and its byproducts are digested by specific fungi as it degrades.

These incredible organisms can even help refine bio fuels. Whether or not we go as far as using fungal coffins to decompose our bodies into nutrients for plants — well, that’s a debate for another day.

But one thing is for sure: fungi have the undeniable potential to be used for a whole range of purposes we’re only beginning to grasp.

It could be the beer you drink, your next meal, antibiotics, a new faux leather bag or the packaging that delivered it to you — you never know what form the humble mushroom will take tomorrow.

Mitchell P. Jones, Postdoctoral researcher, Vienna University of Technology

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

80% of household water goes to waste – we need to get it back

Roberta Ryan, University of Technology Sydney

As regional Australian towns face the prospect of running out of water, it’s time to ask why Australia does not make better use of recycled wastewater.

The technology to reliably and safely make clean, drinkable water from all sources, including sewage, has existed for at least a decade. Further, government policy has for a long time allowed for recycled water to ensure supply.

The greatest barrier to the widespread use of recycled wastewater is community acceptance. Research from around the world found the best way to overcome reluctance is to embrace education and rigorously ensure the highest quality water treatment.

In 2006 Toowoomba voted against introducing recycled water, despite extensive drought gripping the area.
Allan Henderson/Flickr, CC BY

Why not use stormwater?

Many people are happy to use recycled stormwater, while being reluctant to cook, drink or wash with recycled household wastewater. But there are technical, cost and supply issues with relying on stormwater to meet our country’s water needs. Stormwater has to be cleaned before it is used, the supply can be irregular as it is reliant upon rain, and it has to be stored somewhere for use.

On the other hand, household wastewater (which is what goes into the sewerage system from sinks, toilets, washing machines and so on) is a more consistent supply, with 80% or more of household water leaving as wastewater.

Furthermore, wastewater goes to treatment plants already, so there is a system of pipes to transport it and places which already treat it, including advanced treatment plants that can treat the water to be clean enough for a range of purposes. There are strong economic, environmental and practical arguments for investing more effort in reusing wastewater to meet our water supply needs.

This water can be used for households, industry, business and agriculture, greening public spaces, fighting fires, and topping up rivers or groundwater.

The water cycle

Technically, all water is recyled; indeed we are drinking the same water as the dinosaurs. Put very simply, water evaporates, forms clouds and falls as rain, and is either absorbed into the earth and captured underground or filtered through rock and goes back again into oceans and rivers.

When we capture and reuse water, we are not making more water, but speeding up the water cycle so we can reuse it more quickly.

Not pictured: the many, many animals and people every drop of water has passed through over millennia.
Wikimedia Commons, CC BY-SA

We do already reuse wastewater in Australia, with many parts of regional Australia cleaning wastewater and releasing it into rivers. That water is then extracted for use by places downstream.

Despite this, there have been significant community objections to building new infrastructure to reuse wastewater for household use. In 2006, at the height of the Millennium drought, Toowoomba rejected the idea entirely.

However, since then a scheme has been successfully established in Perth. We must examine these issues again in light of the current drought, which sees a number of Australian regional centres facing the prospect of running out of water.

Lessons from overseas

Singapore has had enormous success in reusing wastewater for all kinds of purposes.
EPA/HOW HWEE YOUNG

Despite initial reluctance, many places around the world have successfully introduced extensive wastewater recycling. Places such as Singapore, Essex, California, New Mexico, and Virginia widely use it.

Recent research from the Water Services Association of Australia, working with other research bodies, found several key lessons.

Firstly, the language we use is important. Phrases like “toilet to tap” are unhelpful as they don’t emphasise the extensive treatment processes involved.

The social media and news outlets can play an significant role here. In Orange County, California, wastewater was introduced through a slow process of building acceptance. Influential individuals were enlisted to explain and advocate for its uses.

Secondly, communities need time and knowledge, particularly about safety and risks. Regulators play an important role in reassuring communities. In San Diego, a demonstration plant gave many people the opportunity to see the treatment process, drink the water and participate in education.

We need to go beyond information to deep consultation and education, understanding where people are starting from and acknowledging that people
from different cultures and backgrounds may have different attitudes.

El Paso successfully introduced wastewater through strong engagement with the media and significant investment in community education, including explaining the water cycle.

Finally, quality of the water needs to be great and it needs to come from a trustworthy source. The more it happens, and people know that, the more likely they are to feel reassured.

It’s clear the public expect governments to plan and act to secure our future water supply. But we can’t just impose possibly distasteful solutions – instead, the whole community needs to be part of the conversation.

Roberta Ryan, Professor, UTS Institute for Public Policy and Governance and UTS Centre for Local Government, University of Technology Sydney

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

How to get people to eat bugs and drink sewage

Disgust may be an impediment to many of us adopting more sustainable lifestyles, from considering alternative foods to drinking recycled water
http://www.shutterstock.com

Nathan S Consedine, University of Auckland

In wealthy societies we’ve become increasingly picky about what we eat. The “wrong” fruits and vegetables, the “wrong” animal parts, and the “wrong” animals inspire varying degrees of “yuck”.

Our repugnance at fruit and vegetables that fail to meet unblemished ideals means up to half of all produce is thrown away. Our distaste at anything other than certain choice cuts from certain animals means the same thing with cows and other livestock slaughtered for food. As for eating things like insects – perfectly good in some cultures – forget about it.

Disgust has its advantages. Its origins likely lie in the basic survival benefit of avoiding anything that smells or tastes bad. But disgust may also be an impediment to many of us adopting more sustainable lifestyles – from eating alternative sources of protein to drinking recycled water.

Can anything be done about this? The fact that disgust varies between cultures and across ages implies it can. But how?

We set out to answer this by getting a better grip on how disgust works, focusing on disgust in everyday food choices, rather than aversions to the unknown or unfamiliar.

Our research suggests some disgust responses, once set early in childhood, are hard to shift.
But responses involving culturally conditioned ideas of what is “natural” may be modified over time.

Don’t eat that!

Disgust likely began as a powerful “basic” emotional reaction that evolved to steer us away from (and literally eject) potential contaminants – food that smelled and tasted bad. You can think of it as originally being a “don’t eat that” emotion.

The disgust system tends to be “conservative” – rejecting valid sources of possible nutrition that have characteristics implying they might be risky, and guiding us towards food choices that are ostensibly safer. Research by University of British Columbia psychologist Mark Schaller and colleagues suggests people who live in areas with historically high rates of disease not only have stricter food preparation rules but more “conservative” cultural traditions generally.

Is is unclear exactly how or when individual templates for what is disgusting are set, but generally what is seen as “disgusting” is set relatively early in life. Culture, learning and development all help shape disgust.

It’s just not natural!

In our study, we showed 510 adults pairs of “normal” and “alternative” products via an online survey, and asked them how much they would be willing to pay for the alternatives. We also asked them to rate which product was tastier, healthier, more natural, visually appealing and nutritious. Product pairs included:

shiny and typically shaped fruits and vegetables vs knobbly, blotchy, gnarled and multi-limbed examples.
plant protein foods vs insect-based foods
standard drinks vs drinks with ingredients reclaimed from sewage
standard medicines vs medicines with ingredients extracted from sewage.

Out of shape: using common fruits and vegetables meant the study’s results were not muddied by responses affected by fear of the unknown.
http://www.shutterstock.com

Our results show that, even after statistically adjusting for obvious factors like pro-environmental attitudes, those with a greater “disgust propensity” are less willing to consume atypical (weird-looking) products.

This may seem rather obvious but most prior studies have muddled a food’s “novelty” with its possible disgusting properties (by asking people, for example, whether they’d eat bugs). By asking about really common fruits and vegetables, our study shows just how far disgust may reach in influencing what we consume.

As importantly, our results suggest evaluations of a product’s perceived naturalness, taste, health risk, and visual appeal “explains” about half of the disgust effect.

In particular, lack of perceived “naturalness” was a frequently reason for unwillingness to pay for product alternatives. This result was in line with previous studies that have looked attitudes to eating insects or lab-grown meat. This is a promising area for social marketing.

Therapeutic responses

Given evidence about how much of what we consider disgusting is cultural and learned, marketing campaigns could help shift attitudes about what is “natural”. It has been done before. Consider this advertisement to naturalise sugar consumption.

Thinking differently about emotion-eliciting stimuli is termed “reappraisal”. Reappraisal has been shown to reduce disgust effects among those with obsessive compulsive disorder. Desensitisation (repeated exposures) seems less effective in reducing disgust (versus fear) among people with diagnosed phobias, but it may work better among the general population.

Of course, such speculations remain untested and their ultimate success remains unclear.

But it wasn’t so long ago that Western consumers turned their noses up at fermented foods, and the notion of “friendly bacteria” made as much sense as “friendly fire”. More than a decade ago the residents of a drought-stricken Australian town voted against recycling sewage for drinking water. Now the residents of an Australian city accept recycled sewage being pumped back into the city’s groundwater.

Given time, circumstance and a little nudging, a future meal at your favourite Thai restaurant may well involve ordering a plate of insects.

Nathan S Consedine, Professor of Health Psychology, University of Auckland

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

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.

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.

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).

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.

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.

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

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.

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

File 20180307 146650 1v2p3a9.jpg?ixlib=rb 1.1 — 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.

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.

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.

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.

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.

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

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

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

Stuart Khan, UNSW Australia

Concerns about drought and water supply are once more building in eastern Australia. Recent reports from Victoria show the state government is considering switching on the so-far-unused desalination plant to supply Melbourne. While Melbourne doesn’t currently need extra water, this might free up other water allocated to the city to be diverted to regional communities in the north of the state where water shortages are looming.

When drought strikes, people and governments look to shore up water supplies. In Australia, politicians have focused on building more dams and long pipelines, at the expense of alternative sources such as recycled water.

It has been widely assumed that drinking recycled water, from sources such as sewage, is not acceptable to the public. But an Australia-first survey released by the Australian Water Association shows the public is ready to accept recycled water.

Water is getting further away and more expensive

Since colonisation, we have tapped increasingly distant, more energy-intensive and more expensive sources of fresh water.

We have constructed large dams to buffer variable water supplies through wet and dry seasons, as well as wet and dry years. As water consumption has exceeded the capacity of river basins to meet demand, we have constructed long pipelines, to pump water in from less populated river basins to more populated basins.

During the last decade, many of our major cities began to identify that the capacity to pump more water from distant locations was approaching sustainable limits.

New sources of water were required. So, in a very short period of time, cities including Perth, Sydney, Melbourne, Adelaide and the Gold Coast set about constructing seawater desalination plants.

Hindsight comes with 20-20 vision and it’s clear that most of these desalination decisions – with the notable exception of Perth’s – were premature since the plants have barely beeen used. Politicians and those with a financial interest in these plants often comment that the desal plants represent great “insurance policies” for when the next drought inevitably arrives.

However, these “insurance policies” came with billion-dollar price tags. Much of this has been externally financed, thus accruing significant annual interest costs.

Furthermore, the costs associated with maintaining desal plants are significant – even when they supply zero or negligible water. In some cases, such as Sydney, the real need to use the desal plant – given effective demand management – is likely to be still many years away. As such, it is arguable that these desal plants were very poor value insurance policies.

The lure of desalination

In 2006, the New South Wales Parliament undertook an Inquiry into a Sustainable Water Supply for Sydney. I appeared as a witness to that inquiry to put forward an argument that there was a more sustainable option than seawater desalination.

I argued that the technology was established to reliably purify water from sewage treatment plants to such a high degree that it would be capable of providing extremely high-quality drinking water for Sydney. This practice has been adopted in a number of US cities and is commonly referred to as “potable water recycling”.

All towns and cities are physically unique in terms of geography and historic development features. However, in the right mix of circumstances, potable water recycling can have significant advantages over seawater desalination.

These can include reduced operation and construction costs, as well as much lower energy requirements, which translate to reduced carbon emissions. Nonetheless, the suggestion that the NSW government seriously consider potable water recycling as an alternative to seawater desalination was not widely appreciated.

The general wisdom of the time was that Australians would not be prepared to accept water that was once sewage as a component of their drinking water supply. Indeed, this appeared to be supported by a telephone survey around that time.

Since then, the New South Wales and Victorian state governments have made statements that potable water recycling is not even an option for consideration by cities in those states.

Political thirst for dams

It is widely recognised that most opportunities for building dams on rivers to provide water for Australia’s large cities have been effectively exhausted.

Nonetheless, Australian politicians appear to yearn for opportunities to announce a new big dam project. When the federal member for Calare, John Cobb, announced a plan to dam the Belubula River at Needles Gap (NSW) in 2014, he declared: “I believe this project will lift the spirits of the central west and will inspire all of regional Australia.”

Water supply projects may have many diverse objectives, and inspiring all of regional Australia may be an understandably important one for a politician. However, many politicians appear to carry some unshakeable assumptions about community water supply preferences in Australia. Most seem to think we all want to hear announcements for new big dams.

And if we can’t have new big dams, they think desalination plants are our next preferred option. Few politicians deny the sustainability advantages of potable water recycling, but most seem to think it’s just too difficult to bring the community on board to support it.

Attitudes are changing

In the recent survey, 3,316 completed responses were received from community members across Australia.

Of these, 69% agreed or strongly agreed with the statement that recycled water “can be treated and managed for safe drinking”. This compared with 56% who agreed with the same statement for stormwater and 82% who agreed for seawater desalination.

Given the prevalence of actual seawater desalination plants around Australia and a lack of any public discussion about potable water recycling, I suggest that this level of faith in the capabilities of recycling plants is remarkable.

Recent research from the United States has shown that by engaging the community and providing accurate information, the underlying level of support for recycling can be significantly increased.

When consumers were asked whether they agree with the statement that “there is scope for more dams to provide additional water supplies in the south of Australia (e.g. in the Murray-Darling Basin and the south-east coastal areas)”, only 33% agreed. This rose to 46% for northern Australia. So much for inspiring all of regional Australia.

Preparing for the dry

Worldwide, countries are preparing for the significant El Niño event underway. Evidence is rapidly building that the east coast of Australia will again be subjected to the drought-causing conditions that have led to major water shortages in previous decades.

When this happens, we can expect many regional areas to struggle in their management of dwindling water supplies. Many will be searching for sustainable water supply solutions and some will identify potable water recycling as the most sustainable option for their circumstances.

The challenge for the federal and state governments will be to support the needs of these towns and cities. They will do that best by ensuring that all potential water supply options are on the table and given fair consideration.

In the meantime, our politicians would serve regional Australia best by ceasing to stigmatise potable water recycling as an option that is not even entitled to consideration.

Instead, they should work to build upon the support that currently exists in our communities so that when the need arises, potable water recycling is a viable and broadly accepted water supply solution. There is already powerful evidence that this can be achieved, when state governments work constructively toward this goal.

In 2013, the Western Australian government gave strong support and approval for a potable water recycling project to provide up to 20% of Perth’s water supply. That plant has since been constructed and will soon begin replenishing one of the city’s essential, but dwindling, groundwater supplies.

Stuart Khan, Associate Professor in Environmental Engineering, UNSW Australia

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

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