Perth: Water treatment question.?

Question

I just saw an episode on the treatment of ocean water to make it drinkable, Well I was wondering....Would the salt that is collected and put back into the water, making the water extra salty, would that not change the water ecosystem?

Answer 1

The process used in Perth is one where half the water pumped from the ocean is made into drinking water, and the other half is pumped back into the ocean with twice the concentration of salt. Some concerns were raised over the siting of the plant and the outfall, as the water is pumped back into Cockburn Sound which is relatively enclosed, and an important fish breeding ground. Studies have been carried out to say that it shouldn't be a problem, but I believe there is also a requirement that the effects are monitored.

Answer 2

It might very close to the outfall, or if the outfall was in a confined area that did not get flushed by tides.  There would also be an effect if the brine was discharged into what had formerly been fresh water.  However the amount of water removed for desalination, and the amount of concentrated brine returned, is minuscule compared to the volume of water in the ocean so any concentration would disperse quickly.

Answer 3

The outfall is monitored for exactly that reason. I believe there have already been attempts to get the allowable levels increased.