Rodi on a well

akaemu · Sep 12, 2016

Does anybody else worry about a well running dry to create rodi water? Is this something I should even be worrying about? I'm assuming I'm using roughly 20 gallons of water per 5 gallons of useable water. I've been thinking about it and I'm going to assume I would burn the well pump up before running out of water but I really have no idea.

Rick.45cal · Sep 12, 2016

If your well runs dry from running an RO/DI unit, then you've got some serious problems. Especially if it's fed from aquafers. It's improbable that your well pump will burn up, mine barely notices the RO/DI.

If your well water is anything like mine, the dissolved CO2 will burn up your DI resin pretty quick. I only get about 150-160 gallons from a single DI cartridge refill before it becomes exhausted.

akaemu · Sep 12, 2016

Thanks. So this is something I shouldn't even worry about. So far id be extremely happy if I got 160 gallons of useable water out of one di cartridge. I moved from city water to a house with a well and I'm lucky if I get 75 gallons of useable water out of a di cartridge at both houses. I might need to change my membrane or something ( sediment filter/carbon changed with in every 3 months) but the rodi unit is only one year old if that. People keep telling me I'm going to run the well dry or burn the pump up.

mike007 · Sep 12, 2016

If you have a septic system could effect your leach lines.

AZDesertRat · Sep 12, 2016

Yes you get 5 treated gallons and 3 to 4 times that waste but this I over the course of a couple hours so only ounces of water a minute.
To know if your system is operating at its best you need to answer several questions.
What is your well water TDS, RO only TDS before the DI filter, and final RO/DI TDS? What is the well water calcium carbonate hardness? To determine if you have CO2 in the water, what is the well water alkalinity and pH? What is the well pump pressure switch set at? What is your pressure on the RO pressure gauge and your water temperature? What is your exact measured waste ratio?

akaemu · Sep 12, 2016

I will have to get back on this. It's too many unknowns. I can say coming in to the tds meter pre Di is 13 and going out is 0. Pressure is anywhere from 50-35 on the gauge.

Rick.45cal · Sep 12, 2016

Lots of factors go into how much you get out of a DI cartridge. Mine runs through a 100 micron sediment screen prefilter (my well water has sediment in it) then into a 5 micron particulate filter, an aquatec 8800 booster pump, then into the 1 micron sediment filter, before 2 carbon filters then the membrane. Post membrane pre-DI I get a TDS of 9 then 2 DI stages. My booster pump pushes the pressure up to 80 psi, which increases the efficiency of the membrane. You are probably in the low range of pressure. At those pressures your RO membrane doesn't work as efficiently meaning you are generating excess wastewater and getting little in return.

jsker · Sep 12, 2016

Use your waste water for the wash

Rick.45cal · Sep 12, 2016

If you have a septic tank don't dump old waterchange saltwater down the drain! That would likely be a big mistake

AZDesertRat · Sep 12, 2016

Actually saltwater can be good for some clay bearing soils, it helps break the clay down. The salt in your aquarium is nothing compared to water softener brine and people have been sending brine to septic systems for decades.

Rick.45cal · Sep 13, 2016

Interesting point. Makes perfect sense.

Mine will continue to go outside as it leaves via a python to an area in my backyard where water drains from a screened enclosure that I have.

ChytownPrincess · Sep 13, 2016

I am on a well...in fact it is fed from the Oglala Aquifer. The part of the country that is sustained by this water source has been in a drought since at least 2003. I think that you have a valid concern...I share them with you.... the waste water is horrible, so I have been looking at various uses that would help with this issue. Do you have or have heard of any solution?

Buckeye Hydro · Sep 13, 2016

If you consider a 100 gpd RO system run at a 4:1 ratio, it processes, all told, about 0.3 gallons of water per minutes. For context, your kitchen sink is about 10x that amount, and a garden hose hose about 15x that amount per minute.

At my house the RO waste is used for laundry.

Russ

Buckeye Hydro · Sep 13, 2016

Rick.45cal said:
Lots of factors go into how much you get out of a DI cartridge. Mine runs through a 100 micron sediment screen prefilter (my well water has sediment in it) then into a 5 micron particulate filter, an aquatec 8800 booster pump, then into the 1 micron sediment filter, before 2 carbon filters then the membrane. Post membrane pre-DI I get a TDS of 9 then 2 DI stages. My booster pump pushes the pressure up to 80 psi, which increases the efficiency of the membrane. You are probably in the low range of pressure. At those pressures your RO membrane doesn't work as efficiently meaning you are generating excess wastewater and getting little in return.

Good line of thinking - the original poster would benefit from a booster pump, especially if excessive water use is an issue.

Rick - in an ideal situation you'd move your booster pump so that is it AFTER all the prefilter housings.

Russ