Friday, July 24, 2009

Wonderful Water

Had a wonderfully serendipitous event today. In the right place at the right time got a technical tour of Hamilton Water Treatment Station. (Thanks Mark and Carl).

A couple of things I was very pleased to know:
  • Incredible amount of effort goes into producing potable water. It goes through screens, filters (three kinds, floating, sand and carbon), UV and finally chlorine.
  • That they measure the level of fluoride in the water, before dosing up to 0.75ppm that the regulations say (I don't agree with this, but that will be another post)
  • They add aluminum sulfate / Alum in the initial stages as - it is a critical part of the filtration. However most of it comes out with the sludge (it is a flocculation devise) which gets sent to the wash water treatment station, so doesn't get back into the water. This is important as Huntly water intake is considerably down stream, and I don't want extra aluminum in my water !
  • They dose lime back into the water. This is because after the processing (mainly the Alum) the water is slightly acidic. Therefore this would attack the metal pipes. The lime slightly raises the pH to stop this, but if to much lime is added then the pipes have a scale build up. So it is a delicate balancing act. From human point of view, this adds extra calcium to the water, which is great as we all need more calcium.
And found these things shocking
  • That in the 2008 drought they max'ed out at 88 000 m^3 of water supply, 90 000 is considered total possible max. Thus that day implemented total sprinkler ban. The day that the ban kicked in the water consumption dropped down to 55 000 m^3. (Note these numbers might not have the right unit or right number of zeros). The point is that this an incredible amount of wastage. If people mulched and used permiculture principles there would not be the need for so much watering, abit 2008 was an exceptationally dry summer.
  • Think of the energy wasted in filtering and pumping the water, and all the wear and tear on the equipment that is unnecessary.
  • Lastly think of all the chlorine that is being pumped into the soil. I would expect this to have a detrimental effect on the microbes in the soil, thus impacting the plant nutrition. This could well be important when growing vegetables!
I have already blogged about water treatment on this blog and it was not in a very positive light. However this trip has made me appreciate how complex createing potable water really is and how it is as much an art and knowhow, as it is scientific rules.

No comments:

Post a Comment