A couple of weeks ago, a new desalination plant to supply water to Perth, Western Australia was opened. A day later they held an ‘open day’ for the general public, and in November 2011, after a couple of months of final testing, the first water from the plant will be supplied to Perth.
As the desal plant is not that far from where I live, I decided to visit it on the Open Day. I’m glad I did. It was fascinating. I already had some understanding of a reverse osmosis desal plant based on the environmental documents I’ve been editing the past three years for a different project — that knowledge meant I was able to ask some reasonably techie questions and not look like a fool!
We got taken around the plant by bus (it’s a BIG plant with many buildings). We were only allowed into two of the main buildings — the filtration and reverse osmosis buildings — and some of the outside areas. We were driven past the pumping rooms, initial filtration areas, main storage tank, the admin complex (where the control room is), the electrical room (where they convert 132,000 volts [!!!] into 11,000 volts then down to 415 volts), but weren’t shown inside any of these. And the intake and outfall pipes are well out to sea and are all underground so we couldn’t see any of those either.
I was impressed with how clearly everything was signed, and that they’d used color-coding for the pipes — filtered sea water was clear blue, brine was dirty blue/green, chemicals were mauve/purple, permeate was green, etc. All that makes it so much easier to see and understand what you’re dealing with in an emergency.
And I was amazed at the kilometers of cabling and piping throughout the plant — all of which was beautifully arranged, laid out, tagged, and tied off. Even so, it would still be a nightmare to follow a particular cable’s path…
Order in the cables
Another thing that was amazing was the technology used in the filtration stages. In the final stages prior to the reverse osmosis process, the sea water is pushed through tiny fibers in long columns. Each tiny fiber has a hole down the center and many even tinier holes along its length. I looked carefully and felt the fibers, but there was no way I could see or feel those holes, which are measured in microns.
Part of the filtration building
The long filtration tubes are filled with thousands tiny fibers, each of which has hundreds of even tinier holes
Reverse osmosis (RO) building
RO building; Anna, Project Engineer
Reverse osmosis sampling station, where they can sample water from each RO tube
Back of RO sampling station
Stainless steel piping and join -- stainless steel pipes are only used for high pressure piping; otherwise, they use fiberglass. The nuts on EACH of these joins are about 2 inches in diameter.
One other thing that I found out related to the wash stations in case of chemicals being spilled onto the skin, face, or eyes — each had a green light above it. We asked why. It seems that green is the last color spectrum that the eye can see in the case of a chemical splash, so the green light at the wash station means that the signs can still be read by someone who is otherwise unable to see.
Chemical wash station
One of the external tanks containing solution for the RO process
All in all it was a great day for anyone interested in how things work (me!), and it was a great example of usability in practice.