[Mike55]

Is it better to run RO membranes in series or run them parallel?

Is there a big difference in the production rate of pure water and does running them parallel produce much higher waist?

Also does it have any major effect on the life of the membrane?

Cheers
Mike

[Mike55]

That's higher 'waste' and not as in simon cowells trousers..... 

[mikecam]

If you run parallel , assuming a waste ratio of 60% waste, 40% product for each RO membrane then thats still your final waste ratio, 60%. If you run in series at the same ratios, then you will be re using the 60% waste from the first RO, and 'wasting' 60% of that.
 100 litres=40 litres product=60 litres waste, through another ro 60 litres waste will give you 24 litres product and 36 litres waste.
 Total waste for 100 litres parallell = 60 litres.
 Total waste for 100 litres series = 36 litres.

[Mike55]

Thanks mate.

On that basis will it wear out the second membrane quicker in series as it is trying to purify waste water or is the effect to small to worry about?

[Nathanael Jones]

Thanks mate.

On that basis will it wear out the second membrane quicker in series as it is trying to purify waste water or is the effect to small to worry about?

It will kill the end membranes slightly quicker,.. but if you have decent pressure and use an auto flush then it should still last a long time. I know some pumped systems have up to 5 membranes in a row and kick out very little waste.

[Topclean]

will running 2 in series give better tds?

[mikecam]

will running 2 in series give better tds?

no mate.