Treated Sewage, Would You Drink It? (Part 3)

In Part 1 we took a look at why we needed to look at drinking treated sewage and in Part 2 of this article looked at the reasons people wouldn't drink it and some of the places that it is being used today.  

In this final part, I'll share the results of the poll that I ran on LinkedIn.

Image via WikipediaThis is nowhere near as exhaustive as the polls undertaken by more sophisticated methods but it did sample a very wide ranging group of people.

There were responses from Saudi Arabia, the US, the UK, Australia and India as well as several others.  


Respondents were both male and female and came from a wide range of professions and industries.

The responses indicated that 72 percent were in one way or another willing to drink treated sewage, based mostly on the understanding that water is precious and needs to be used more intelligently.

LinkedIn Poll Results:

View the detailed results at LinkedIn

Results for the entire Poll are available on a separate page here.

Clearly, there is still a significant number of people who would not drink treated sewage, however, it seems that most people are pragmatists and believe that we need to seriously consider drinking this water.

Treated sewage needs to be considered as part of the overall strategy for ensuring the security of drinking water in Australia.  That there is still a significant percentage of people for whom "NO" is the only answer should not be overlooked, nor should their concerns be shoved aside in the haste to employ this technology.


That there are a number of operating plants around the world, regularly providing treated sewage for people to drink proves that this can be done in a safe and sustainable manner addressing many of the legitimate health concerns that people have.


Perhaps with a little more time for the operational plants to prove themselves and some education regarding these successful operations, even the most ardent opponents can be swayed.

 

Treated Sewage, Would You Drink It? (Part 2)

Part 1 looked at the why and how of recycling sewage to drinking water.  The technology is operating around the world, effectively and acceptably, for example in a plant in Orange County, California amongst others.

So, what causes resistance to this technology?

"It is quite difficult to get the cognitive sewage out of the water, even after the real sewage is gone."

- Carol Nemeroff, psychologist

So, what does that mean?

Manhole cover, Rome, Italy

Basically it means that despite the fact that the recycled water is purer than normal source water, once it's had poo in it, that thought lingers long after the smell has gone.  This is a problem that needs to be overcome when you think how little fresh water is available in the world.

On a planet that's seventy percent water it is estimated that only 3% of all water is fresh water and of that, with so much tied up in ice caps, glaciers and ice bergs, only 1% of the water is readily available. 

With the burgeoning human population the demand on this precious resource for both drinking and for watering the crops and livestock that will feed us will only increase.

A professor in the US, Brent Haddad thinks that this method of producing fresh water is a rational way forward stopped by irrational objections from the public.  He realised that this was more of a problem for psychologists than engineers. 

In a study of 2000 people he asked why people had such a problem drinking recycled sewage.  His study showed that 60% of those surveyed would not touch this type of water.

Likewise in a 2007 referendum, in Toowoomba in Queensland, Australia, more than 61% of the eligible 60,231 voters voted against the proposal to build a treatment plant to augment their water supply.  This is despite the fact that the city had experienced severe water restrictions that banned the use of town water on lawns, and eventually gardens and potted plants.

However, there are places in the world where this is being done today.

Windhoek, the capital of Namibia uses recycled water for drinking water during times of drought.

The South African cities of Scottsdale, Pretoria and Cape Town rely on indirect schemes, where recycled sewage is introduced back into a river, dam or aquifer.  There it mixes with the rest of the water before being retreated for drinking, effectively taking the poop factor out of the equation.

In Singapore, about 1% of recycled sewage water is used for drinking.

Perth water Corporation advanced treatment plant

In Perth in Western Australia, the Perth Water Corporation has a pilot plant operating producing drinking quality water.  They are removing the “poo” factor by discharging into aquifers where it co-mingles with ground water and is later pumped out and treated as part of the normal supply.

Approval to discharge was granted on 9th November 2010 and as at the end of August 2011, 872 megalitres have been injected into aquifers.

The trial is being overseen by the WA Department of Health, WA Department of Water and WA Department of Environment and Conservation.   

It is partly-funded by the Australian Government’s Water For the Future initiative.

Using LinkedIn, I asked my contacts to answer the following question from 4 options:

WOULD YOU DRINK TREATED SEWERAGE?

1.      No way, no matter how it was treated

2.      Yes, water is precious we should reuse

3.      Maybe, if it was mixed with pure water

4.      Only water is in short supply

I’ll share the results later when the poll closes but if you look at the right of the page, you can click to vote too.

When you think about it, all water has been sewage at one point in time.  Everyone lives downstream of someone or something, even animals poo and pee in our rivers and dams.

Some major towns in Australia are taking their source water from rivers that are having treated sewage discharged upstream of them.

So, we are already drinking sewage of one type or another, so isn’t producing this proven, technically competent manner a method that should be incorporated into any sustainable water management policy?

Treated Sewage, Would You Drink It? (Part 1)

Photo by  Tomas Castel

Drought is a part of life in Australia.  Our great rivers, the Murray Darling System, the Murrumbidgee and others are often little more than sluggish brown streams.  Salt laden, polluted and full of nitrates from fertiliser run off, this is where much of Australia’s drinking water comes from.

The water management strategies employed by our politicians often seem to be aimed at giving history the opportunity to remember the politicians for the landmark projects they created rather than remembering them for developing effective and inclusive strategies that provide real results and benefits for the environment.

Desalination seems to be regarded by many as the panacea for all that ails our water systems while storm water harvesting and treating sewage to recycle as drinking water are often overlooked.

Treated sewage provides a convenient resource and here’s how it could get from the home back to our tap.

In large cities around the globe, sewage and waste-water is collected from homes and storm-water drains via a sewerage system and then it gets processed at a treatment plant.


At the first stage the sewage passes through a filter to remove large materials like tree limbs, garbage, plastics and large organic matter.  From there it passes to the primary sedimentation tank, where sludge settles to the bottom and lighter liquids like grease, oil and soap rise to the top. The surface is skimmed off while the sludge is pumped away to a separate treatment facility.

From there, it’s pumped to another tank where bacteria breaks down any remaining organic matter in the wastewater, oxygen is pumped into the fluid to encourage the bacterial activity. The next step is more filtering, microfiltration that removes suspended solids, protozoa, bacteria, and some viruses.

The last step is to disinfect the water, often by the addition of chlorine, hydrogen peroxide and other chemicals and by running it past high intensity ultraviolet lights.

Image via WikipediaFrom here it can be “shandied” into the water supply pipeline or other ways like a river, or pumped into the ground, where it is reintroduced into the below-ground water supply.

Years later, after natural filtration, the water is extracted as part the wider supply network.  It is all treated together as part of our domestic water supply.

 So, what’s the problem with this?  The treated water itself is often cleaner (purer) than the original source water before treatment. 


Almost everyone lives downstream of someone or something, so the raw product that's turned into our drinking water today isn't so pristine after all.

As reported in the Melbourne Age in 2008:
"The Victorian government is opposed to the drinking of recycled sewage, despite a study in 2006 finding it could be done in Melbourne at less financial and environmental cost than seawater desalination.
Despite the policy ban, many Victorian towns along the Murray River effectively drink recycled sewage already, by taking their drinking supplies from rivers that are boosted by the treated wastewater of towns upstream."


Maybe taking a long, hard and rational look at this technology isn't such a bad idea?

The technology exists and is at work in places like Orange County, California, so it’s not a technical issue that's stopping the wider adoption of this alternative, it’s all psychological and part 2 delves into this issue.