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I was on holidays during National Water Week, but to make sure I didn’t miss out on the fun and excitement, I looked up NWW activities at my holiday location – Alice Springs. And so I spent the morning of my last whole day in Alice at the open day at Alice Springs Water Reclamation Plant.
The plant was designed to protect the nearby Ilparpa Swamp from the overflow from the wastewater stabilisation ponds. The plant treats 600 megalitres of water per day, most of which is pumped 6.2 km to the Arid Zone Research Centre. Some of the water is used to irrigate Blatherskite Park, which was previously irrigated with water directly from the stabilisation ponds.
In this part of the plant, water is treated with sulphuric acid to adjust pH, cationic polymer and aluminate to coagulate and flocculate.
The water from the end ponds is pumped to the plant, where the pH is adjusted with sulphuric acid prior to coagulation with a cationic polymer and flocculation with aluminate. Although some solids are removed in the ponds, the intake water for the plant contains large amounts of algae which are removed in the coagulation/flocculation process.
The second stage of the treatment is Dissolved Air Flotation. The removed solids are returned to the ponds, and the clarified water is then chlorinated and sent to the reclaimed water tank. A critical control point sends the water back to the pond if any of the on-line monitoring indicates that the water is not meeting the required standard.
Water that does not meet standards is sent back to the wastewater ponds
At the Arid Zone Research Centre the water goes through a final treatment and storage process known as Soil Aquifer Treatment (SAT). Although this process has been in use in overseas for many years, the Alice Springs plant is the first in Australia. The water is stored in basins located over the original Todd River artesian basin where potable water will be stored underground for future reuse.
Built at a cost of A$10.4M, and opened in May 2008 the project has won awards for its architectural design. Let’s hope it is similarly successful in its application.
The grounds of the plant have been landscaped by Greening Australia using local native vegetation and water from the plant.
I’ve added more photos to the Smartwater Flickr group.
Sometimes some things leave you almost speechless. We spotted this sign at the health food shop at our local plaza.
Sign advertising water purifiers
One important research area for Smart Water is Risk Communication. Part of the function of this blog is to address public concerns about reclaimed water and other important water safety issues. To launch our blog, here is a video posted recently on YouTube by dontpoisonme.
The author of the video raises some concerns that many people share. We will address these and many others over the coming months in this blog. But let’s start here with his concern about ‘unknown unknowns’. It may have been better if this phrase had walked out and faded into oblivion with its author, but it has entered the lexicon and we have used it. So let’s look at what is known and unknown about chemicals in the water.
We do know what chemicals can be used in Australia. It is not legal to import or manufacture a chemical that is not on the inventory of the chemical regulators unless you have a certificate or permit to do so. This means we have a pretty good idea of what isn’t there. More on this in a future post.
Not all chemicals can be detected and/or quantified in water. There can be a lot of work in developing methods for chemical analysis. Some of them are pretty tricky. We can take into account some of the characteristics of the chemical, its pattern and volume of use and estimate the likelihood that the chemical will end up in water. This is an important part of the risk assessment process, and we will also post more on this.
The important thing for us as researchers is how to determine if the water is safe if we can’t measure all the chemicals that are in it. The short answer to that is that even if we could measure all the chemicals that are in it, it wouldn’t tell us if the water was safe. We have to come up with another way of testing the safety of the water even if we don’t know its exact composition. So we test the whole water as if it were a single toxin.
Now toxicity testing takes a long time, it is very expensive, it uses animals. Water varies enormously, even over short time frames. So we need tests that are fast (real-time would be great), relevant, economical. We want results that are meaningful to the public who consume the water, the service providers who treat it and the regulators who control it. It’s a tall order, but we’re committed to doing it. After all, we drink the water too.
