Which RO setup?

[Pureserv86]

Hi guys,

This is my first post, I am currently building a round and im at the point where i need to start producing my own pure. Im currently using 200-300 liters a week but i intend to be using about 400l a day so i will want to future proof my setup. My water pressure is 70psi and tds is around 315ppm out of the tap. I will be using a static system and filling up each night. My question is am i better going with something like an ro-man 450gpd or a 40/21. The ro-man claims to be 1/1 waste to pure, does anyone use one and is this correct?

Thanks in advance for any help guys.

Lee.

 

[spruce]

At one time RoMan had 2 inline restrictors in their r/o's. For 'normal' tds they would recommend a 3 to 1 waste to pure ratio and for high tds water they would supply a 5 to 1 ratio restrictor.

The one we had from RoMan was 3 to 1 for 250ppm tap water.

These days the focus is not so much on preserving the membranes at all costs. Sending 2 extra liters of waste water down the drain cost much more than extending the life of 3 membranes by a few months. So by using a tap on the waste you can regulate the waste to pure down to 1 to 1 if you want in exactly the same way you would do for a 4021 or a 4040.

If you want to you can restrict the waste even more to say 1 waste to 2 pure. What you sacrifice is the longevity of your membranes. You also need to consider the amount of resin you will be using. When you restrict the waste too much, the efficiency of the r/o will suffer. You will use more resin polishing the pure off.

In business the term used is 'economies of scale.' You will come to a point where the cost saving doesn't justify the expense linked to it. Where the tipping point is is another subject as it would vary from area to area.

If you are a single operator and you are processing water into a 1000 liter IBC tank you will always have enough. The ideal would be to invest in an auto cut off system so water processing doesn't need your supervision.

The 2 of us managed with a 450gpd RoMan for quite a number of years. We just had to stagger filling times. It all went pear shaped when we added a third cleaner, and even although he was part time, he was fast and got through a lot of water. We were forced to go the 4040 route.

If memory serves me it took about 28 hours to fill an IBC tank in the summer and about 34 hours in the winter when the water was colder. We never used a booster pump and we used the 3 to 1 restrictor with a water pressure of 40psi. Had I restricted the waste to 1 to 1 like our 4040 is set at, it would possibly have produced pure at a slightly faster rate, but it was an exercise I never did.

The quality of our tap water has since much improved to between 99 and 125ppm.

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[Pureserv86]

Thank you spruce, the information is much appreciated. I will get the ro-man 450gpd setup i think and have a play with the tap to find a happy medium.

Thanks alot,

Lee.