Power usage is interesting, with a lot of misconceptions.
A greywater system, running relatively low pressure (say 8m head) is best srved with a 330w - 660w pump (less than a typical pressure pump on a tank, although there is no need to use a pressure pump if using efficient dripperlines, which are at least 50% more water efficient than hosing / sprinklers in any case).
Additional startup consumption is so small to be immeasurable over a 2 second period.
What is interesting is that a 660w pump actually consumes about 400w during use.
A greywater system, with 4 people in the house, generally runs for no more than 0.5 hours per day (if proper greywater irrigation lines are used - irrigation rate is faster than the inflow rate).
Basically the results are 2 kwh per kl of water, or about 0.26 cents per day $$ cost.
I found it facsinating that Nevada water was proud of the fact that their offsite treatment plants (providing class A back to the household) cost approx 10 kwh per kl, and they had been claiming it was the most power efficient method.
Their jaws dropped when I gave my presentation at the Symposium.
If you want more information go have a look at some of our USA info http://www.besthomewatersavers.com/pages/Graywater-Guide.html
Of course factoring in the infrastructure cost of offsite treatment just makes the case stronger for localised water re-use.
Posted Thursday 5 Aug 2010 @ 1:38:17 am from IP
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