rodi tip

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blaxsun

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A couple of things. First, using it for watering your lawn is fine - but they recommend diluting any wastewater with regular water due to the high level of impurities after it runs through the RODI system.

Second, since you're essentially running wastewater back through your RO system - I'm not sure if you'll get the same lifespan with your membranes, filters, etc.

You'd have to think that with such an easy "fix" RO systems would come with this configuration by default. Yet they don't...
 

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A couple of things. First, using it for watering your lawn is fine - but they recommend diluting any wastewater with regular water due to the high level of impurities after it runs through the RODI system.

Second, since you're essentially running wastewater back through your RO system - I'm not sure if you'll get the same lifespan with your membranes, filters, etc.

You'd have to think that with such an easy "fix" RO systems would come with this configuration by default. Yet they don't...
I'm thinking the same thing, burning through membranes and DI. I also wondered about the pressure of the system. Isn't the waste line normally not under pressure, now getting stuck back up on the front pressured line, does that cause any issues to the membrane?

I guess if it come out clean then it works. Half my water bill is fees, paying the fire department, etc, my waste gets put in a rain barrel during the summer.
 

blaxsun

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I'm thinking the same thing, burning through membranes and DI. I also wondered about the pressure of the system. Isn't the waste line normally not under pressure, now getting stuck back up on the front pressured line, does that cause any issues to the membrane?

I guess if it come out clean then it works. Half my water bill is fees, paying the fire department, etc, my waste gets put in a rain barrel during the summer.
I think you'd need a check valve on the waste line for sure. Yes, one would think you'd see an uptick in the overall pressure (at least on the water in line). I hate waste as well, and while this seems innovative - it also seems *too* innovative. I probably waste more water with the average shower than my daily RODI filtration.
 
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What do you mean by get rid of the membrane?

If you are going to run zero waste setup do not run a membrane. Sediment-Carbon-DI. I know there are some people on the west coast where water is high quality and expensive run this way.
 

Chrisv.

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If you are going to run zero waste setup do not run a membrane. Sediment-Carbon-DI. I know there are some people on the west coast where water is high quality and expensive run this way.
Yikes. They must have very low tds to begin with, or a huge budget for di resin. If they think they are being environmentally friendly though, they may not be. My understanding is that consumed di resin is just a massive amount of microplasitics-- so horrible for the environment unless disposed of thoughtfully. I guess some can be regenerated.
 

gbru316

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Yikes. They must have very low tds to begin with, or a huge budget for di resin. If they think they are being environmentally friendly though, they may not be. My understanding is that consumed di resin is just a massive amount of microplasitics-- so horrible for the environment unless disposed of thoughtfully. I guess some can be regenerated.

I’m sure water is used in the manufacture of resin beads, so it’s not even zero waste in the context of water conservation. It’s just shifting use from the consumer to the manufacturer.

I’d be willing to bet that using strictly DI has a greater (negative) environmental impact than RO/DI.

I would think that taking steps to decrease the rejection rate would be more cost effective than just eliminating it entirely.
 

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While I don’t recommend this, I think we’re going to see a lot more on this topic. Especially if your in a drought area with severe water restrictions. There are water districts that are issuing fines and in extreme cases installing flow restrictors on your water meter if you use more water than they think you should be using. I got a little kick back when I asked about reducing water changes due to water restrictions. I already run dual membranes with a booster which supposedly cuts your waste water in half, but that doesn’t calculate flushing. Auto flush systems are great as far as convenience but I’ve found that mine wastes a lot more water than one would think. The problem is where else can one cut back? You already have flow limiting shower heads, faucets, toilets that you have to flush twice, low water dishwasher, high efficiency clothes washer, drip irrigation and rotors (if Heaven forbid you have any grass) on a smart controller. It’s getting to where you have to dip your toothbrush in the toilet to brush before you have your morning constitutional. I know people having grey water recovery systems being installed to capture sink and shower waste water, direct it to a tank and pump it into irrigation and the clothes washer. That’s on top of already collecting rainwater for irrigation. I know this sounds crazy, but it’s happening. These aren’t hippie, commune type people either. These are normal people in somewhat wealthy areas of Southern California.
 
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I thought about doing this just recently, since were in drought conditions. besides the usual cut backs on watering the yard and limiting shower time and etc... I just can't and won't do this just to save water. I run my rodi on the days that are approved for watering the yard and etc. and just hope for the best.
 

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I send mine right to drain. I never know what compounds are in the waste water source and would rather use my garden hose
 

WVNed

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One frequently finds videos on YouTube that test if you paid attention in science class. This is one.

A pipe doesn't care which direction water flows through it. It flows from the end with higher pressure to the one with lower pressure.
The pipe coming in from the supply is the point of highest pressure in an RODI filter.
If you cut it and splice in the waste pipe you have 2 incoming pipes now at the same pressure.

The only exit now is the product pipe.
So the old inlet pipe routes water through the sed filter, carbon block and then hits the membrane.
The new inlet pipe (old waste pipe) goes through the flow restrictor and straight to the membrane.

Now the pressure differential across the membrane is the incoming water pressure applied to the membrane cannister at both the inlet and waste ports and water can only leave by the product port and go to the DI cannisters.
All the stuff normally separated by the membrane and left in the waste water to leave the filter has no where to go.
All the stuff normally removed by the sed filter and carbon block has a direct path to the membrane through the waste line because water is flowing into it now instead of out...that higher to lower pressure thing pipes do.

So all the stuff in the water that entered through the waste line is left in the membrane cannister to collect.
Until it fails.

So how well do you think this works.
 
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Mr. Gonzalez

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Wvned that's what I wanna know. I'm southwest area and my tds is odd from 100-200tds. I wanna know if I rerun my waste back into the ro how fast will the membrane deplete. If it's cheaper to buy membrane over my water bill then I might go this route.
 

Zzyzx

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Wvned that's what I wanna know. I'm southwest area and my tds is odd from 100-200tds. I wanna know if I rerun my waste back into the ro how fast will the membrane deplete. If it's cheaper to buy membrane over my water bill then I might go this route.
Try the BRS water saver upgrade if possible for your rodi unit. You basically add a second membrane and it cuts your waste pretty much in half. Also I run an auto flush system and was shocked to see how much that wastes. I still run it as my water is automated but if I manually made rodi water I would ditch it. The ratio of gallons made to gallons wasted published by most units does not account for flushing
 
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