What does your RODI setup look like?

[Buckeye Field Supply]

I will say that the standard 32 gal Brute Cans you find at Lowes and HD, are not labeled as food safe plastic. I use them, but have always been wary of them. And clean them with bleach on occasion. I would use something different but space issues are the real concern for me.

What information do you have that says these brutes are not food safe hdpe?

 

[11f150]

Beware Rubbermaid trash cans

 

[schooleyosis]

Hmmmm. Been using mine for a year and no issues.

 

[Buckeye Field Supply]

Straight from the horse's mouth:

Gray, white and yellow brutes are certified to NSF Standard #2

NSF/ANSI Standard 2: Food Service Equipment
Equipment commonly known as 'fabricated food equipment': kitchen, bakery, pantry and cafeteria units, and other food handling and processing equipment including tables and components, counters, shelves, sinks, hoods, etc.

for more detail: Rubbermaid Commercial Products - Rubbermaid Waste : 2632 BRUTE® Container without Lid

These are the brutes that are used widely in the hobby, and are available at many hardware stores.

Russ

 

[Dowtish]

What information do you have that says these brutes are not food safe hdpe?

I did the same thing as you, and had to look it up myself, but as many products in the food industry are clearly labeled, these Brute cans are not. You have to know what NSF standard 2 is. I have read multiple threads that have made me leary of using these, but I do stand corrected on the fact that they are "technically" considered food safe plastic. But I can't really say that is good enough for the way we as hobbyist are using them.

 

[Buckeye Field Supply]

I think the real proof is in the fact that these are very widely used in the hobby with success.

 

[saratj1]

Here's my setup , I got it off eBay from MaxWater it is a Canadian company. Cheapest I could find that had the features I wanted.

 

[Buckeye Field Supply]

Ugh.

Make sure it is plumbed such that RO water from the pressure tank never makes it to the DI. Also, you'll want to unclip the DI and orient it vertically with flow going in the bottom and out the top.


Make sure to check and retighten all those Jaco-style compression fittings. The tend to need retightening after the first pressurizations.

Russ

 

[thejoshdavis]

Are any of you guys re-purposing your waste water for anything? If so, for what use? I got my new BRS ro/di yesterday and want to figure out how to make it very economical and utilize the waste water if possible.

 

[Buckeye Field Supply]

At my house I fill the washing machine with it.

 

[schooleyosis]

^^^ That's a great idea!

 

[Electrobes]

Here's mine!

I love it because with a flip of two switches I can either choose RODI for the tank, or RO water to drink (I need it as I am on well water, with avg TDS of 650ppm!). This was fairly easy to do, ever so slightly for a newbie like me to wire, but was all worth it in the end.

 

[thejoshdavis]

After breaking in my ro/di last night I averaged 5ppm in and 0ppm on the usable water. I imagine the in house filter is cleaning a bunch of it up. When I officially get it installed in the garage I imagine that will change drastically. My problem now is plumbing the waste water to usable storage or recirculating it into the house. My garage doesn't have a drain (that I can see just yet). So short of running 30ft of line and flooding my front yard I want/need to reuse the waste.


Sent from my iPhone using Tapatalk

 

[pickupman66]

Adding a second membrane can allow you to gain more water from your waste...I dont remember where I saw it but what I saw you feed the waste into the 2nd membrane and then take the good and T back into the line before your Di resin.

living in the boro, you should seen in teh 2-300 range before any filtration. after the Membrane it should be in the 1-5 range i would guess and then the Di polishes it off. mine goes in at around 1 or two into the DI.

 

[Buckeye Field Supply]

Re adding a second membrane to reduce waste water, first- remember that what folks call "waste water" really would be betterthought of as "flush water" in that this water serves the importantpurpose of internally flushing the surface of the semipermeable membrane tokeep the membrane from fouling/scaling.
Whenyou configure a system with two membranes in series (the waste from the firstmembrane going to the "in" port on the second membrane), for thisdiscussion let's say it's two 75 gpd membranes, the system behaves like youhave a single long (75 gpd x 2) 150 gpd membrane.

Now- if you use a proper flow restrictor, that is, one for a 150 gpd membrane,you'll have about a 4:1 waste to product ratio. Sounds familiar, right?

Ifhowever you don't change the flow restrictor - meaning you keep using thesame restrictor you were using when you just had one 75 gpd membrane, thenyou'll see a waste to product ratio much lower than 4:1. But remember that the recommendation for a~4:1 ratio comes from the membrane manufacturer. They are telling you that youneed about a 4:1 ratio to keep the membrane flushed and keep the membrane fromfouling or building up scale. Run the system with a lower ratio and you willfoul/scale the membrane(s) quicker than would have otherwise been the case.

Insteadof adding a second membrane to lower that ratio, you could have just changedout your flow restrictor ($4) instead. Thisis a much less expensive approach to get you to the same endpoint in terms ofsaving on waste water.

Now,to confuse things just a bit. Filmtec specs call for the 4 to 1 ratio on thebasis of assumptions about the water that will be supplied to the membrane. Ifyou have very soft water you MAY be able to get a decent service life from themembrane running at a ratio lower than 4 to 1 (e.g., 3 to 1). Remember that the waste water from the firstmembrane is about 25% harder than your tap water.

Bottomline: If what you are after is reduced waste water, experiment with a differentflow restrictor for $4 instead of messing around with a second membrane plumbedin series.

Asa side note, you can also lower the ratio by increasing the pressure deliveredto the membrane (with a booster pump), because flow restrictors are sizedassuming you are providing factory spec conditions (50 psi and 77 degrees forFilmtec membranes). Increase the pressure and you'll drive more water throughthe membrane and viola - less waste water. But as I mentioned above, if you do this (justlike over-restricting a membrane) - the lower the waste to product ratio, theshorter the lifespan on the membrane.

Makessense?

Russ

 

[thejoshdavis]

Makes perfect sense. It really makes me wonder if I could possibly plum the "waste" back into the water line to the water heater and let it recirculate

 

[Buckeye Field Supply]

In order to do that you would need a booster pump on the waste water line.

In many locations that is against code because you are introducing dechlorinated water into the potable water supply.

Russ

 

[Dowtish]

Re adding a second membrane to reduce waste water, first- remember that what folks call "waste water" really would be betterthought of as "flush water" in that this water serves the importantpurpose of internally flushing the surface of the semipermeable membrane tokeep the membrane from fouling/scaling.
Whenyou configure a system with two membranes in series (the waste from the firstmembrane going to the "in" port on the second membrane), for thisdiscussion let's say it's two 75 gpd membranes, the system behaves like youhave a single long (75 gpd x 2) 150 gpd membrane.

Now- if you use a proper flow restrictor, that is, one for a 150 gpd membrane,you'll have about a 4:1 waste to product ratio. Sounds familiar, right?

Ifhowever you don't change the flow restrictor - meaning you keep using thesame restrictor you were using when you just had one 75 gpd membrane, thenyou'll see a waste to product ratio much lower than 4:1. But remember that the recommendation for a~4:1 ratio comes from the membrane manufacturer. They are telling you that youneed about a 4:1 ratio to keep the membrane flushed and keep the membrane fromfouling or building up scale. Run the system with a lower ratio and you willfoul/scale the membrane(s) quicker than would have otherwise been the case.

Insteadof adding a second membrane to lower that ratio, you could have just changedout your flow restrictor ($4) instead. Thisis a much less expensive approach to get you to the same endpoint in terms ofsaving on waste water.

Now,to confuse things just a bit. Filmtec specs call for the 4 to 1 ratio on thebasis of assumptions about the water that will be supplied to the membrane. Ifyou have very soft water you MAY be able to get a decent service life from themembrane running at a ratio lower than 4 to 1 (e.g., 3 to 1). Remember that the waste water from the firstmembrane is about 25% harder than your tap water.

Bottomline: If what you are after is reduced waste water, experiment with a differentflow restrictor for $4 instead of messing around with a second membrane plumbedin series.

Asa side note, you can also lower the ratio by increasing the pressure deliveredto the membrane (with a booster pump), because flow restrictors are sizedassuming you are providing factory spec conditions (50 psi and 77 degrees forFilmtec membranes). Increase the pressure and you'll drive more water throughthe membrane and viola - less waste water. But as I mentioned above, if you do this (justlike over-restricting a membrane) - the lower the waste to product ratio, theshorter the lifespan on the membrane.

Makessense?

Russ

Thanks for all your input on this thread. This post is great, as I was just discussing this option the other day with someone. This clears up some things I did not consider.