RO/DI Recovery Rate?

[KingRicky]

I am looking into purchasing a RO/DI System. Talking to a fellow reefer about his, he told me that he gets a 1 to 4 permeate to waste recovery rate. Is this normal? With this rate, you would only get 100 gal. permeate for every 400 gal. of waste. With the cost of sewer rates where I live, it would be cheaper to keep buying RO/DI water from my LFS.

I have tried to find this information on various web site and can't find it. If anyone can help, I would appreciate it.

 

[Gimili the Great]

if you run one of these http://www.bulkreefsupply.com/RO/DI...ving-150-GPD-RO-Upgrade-Kit/product_info.html

with this

http://www.bulkreefsupply.com/RO/DI.../Economy-4-stage-RO/DI-unit/product_info.html

and you have a booster pump but with one you would be getting a much better ratio in what is usable and what is not.

the only down side is you need a booster pump to make sure the psi is around 65 to 70 psi.

but in the long run it is a much better set up, since the second RO membrane in processing the first ones waste and making it usable.

Just my 2¢

 

[Viva'sReef]

Its really expensive and may not be worth it but Spectrapure has a Ultra High efficiency model that is actually 1:2 ratio. 1 gallon of waste: 2 gallons RO/DI

http://www.spectrapure.com/low_waste_systems.htm

 

[Gimili the Great]

dang that is a spendy unit.

 

[KingRicky]

Thanks for the reply's.

I work for a company that builds water treatment plants and am used to systems that have a 4 to 1 recovery rate (4 gallons of permeate to 1 gallon of waste). But these systems measure in MGD "Million Gallons per Day" not GPD "Gallons per Day".

In the big units there will commonly be anywhere from 5 to 30 membrane stages and thay normally operate in the 150 psi range. I just never thought that a home system would be so inefficient. I might have to get my boss to design me a system, if he can design a system for MGD, he should be able to handle 100 GPD.

 

[AZDesertRat]

For a home use system 4:1 is the normal waste ratio. I alike you work with much larger systems but in those we have the ability to add chemicals like for anti scaling and can clean in place and backwash. Most small systems are not designed like this.
Even calculating in sewer as well as water rates its almost always still beneficial to own a RO/DI system over buying water.
If you have good tap water with moderate hardness and low TDS its possible to reduce the water ratio to more like 3:1 but for most of us with a tap TDS in excess of 250 it shortens the life of the membrane drastically.
I make maybe 200 gallons a month so its still only 1,000 gallons of water and 800 gallons of sewage so the cost is still pennies per gallon when you add it up.

 

[TritonsGarden]

Has anyone every used or seen the zero waste units? They have a booster pump on the membrane output that pumps the waste water back into the hot water line.

Jack

 

[Burks]

if you run one of these http://www.bulkreefsupply.com/RO/DI...ving-150-GPD-RO-Upgrade-Kit/product_info.html

with this

http://www.bulkreefsupply.com/RO/DI.../Economy-4-stage-RO/DI-unit/product_info.html

and you have a booster pump but with one you would be getting a much better ratio in what is usable and what is not.

the only down side is you need a booster pump to make sure the psi is around 65 to 70 psi.

but in the long run it is a much better set up, since the second RO membrane in processing the first ones waste and making it usable.

Just my 2¢

Nice idea! I'm moving from a $18 a month water bill to probably closer to $100 a month. The sewer rates in Crestline are i-n-s-a-n-e. My parents average about $150 a month.....

 

[KingRicky]

I live in an apartment in Birmingham, Al, the sewer rates here are the highest in hte country. My sewer bill is already around $70.00. I will have to come up with a system that gives more permeate.

I can buy RO/DI water from my LFS for $.50 p/gal. I am currently using around 30 gal/month.

 

[AZDesertRat]

My wife has family in Crestline! And all the surrounding towns too and she grew up in Tiro.

Zero waste systems have serious limitations are are not really zero waste. They have a practical limit of about 20-25 GPD tops. They dump the waste stream back into your hot water heater by boosting the pressure above your house pressure and the heater has a limited amount of space for additional water and expansion. Not to mention you are now dumping concentrated TDS into your homes plumbing fixtures. Not really a good idea.
I am one of the lucky people who owns the Spectrapure MaxCap UHE system. It is fantastic and really does achieve a waste of less than 1 gallon for every 1 gallon treated. It does so by using a compuer microprocessor and solenoid valves to actually backflush the system with DI water at intervals to keep the membarne flushed. Very unique but also costly to produce and purchase. for me it was worth the investment even though our water and sewer rates are middle of the road. Arizona is going through years of drought and one day in the forseeable future I envision rationing.
By using a booster pump to raise RO membrane pressure you can achieve lower waste but its still better than 2:1 and should be closer to 3:1 if your TDS is in the 250 or above range.