RO water TDS levels

[Steve]

Well, I finally had time to use my new TDS meter. Thought the results were interesting. I am on a private well with a Kent Hi-S 60gpd RO/DI filter.

Tap - soft (which is what is going into the RO unit) - 335
RO - 9
RO/DI - 0
RO waste - 403
Tap - hard - 309
120g tank - 1
25g tank - 1

[AquaFx]

The system seems to be working well. What type of production are you getting? (in Gallon Per Day)

Soft water is the best thing to run into a RO. It will "stop" the scaling on the membrane. Almost every commercial RO in the world is run with softened water.

The readings seem to all be good. If any of them puzzle you I can explain them.

Good luck!

[Steve]

For every good gallon of water I am getting around 5 gallons of waste water. This is a little more then what it should be, but the incoming TDS are higher then 200ppm and I am attributing this to why more waste water is being created. Anybody know if this is true?

[AquaFx]

Your TDS is not that high.

My guess is the pressure is low, let me know what you prefilter gauge reads.

Marianne

[Steve]

I bought a pressure pump so the pressure going into the membrane is usually around 85psi. The pressure coming out is quite a bit lower. I did set up a heat exchange where the water coming off of the cold water pipe goes through a bucket of water with a heater in it. The pressure pump and the heat exchange has helped a lot. Perhaps I need to turn up the temperature on the heater?

[AquaFx]

It sounds like you have a very good handle on RO principles.

The only other thing I can say is check your flow restictor.

Your reject is not that high, but it is higher than you want it. If you look at the permeate pump it reduces reject by up to 80%. It does it with pressure differentials for the most part. Of course the drain line and the flow restictor come into play. I would be happy to forward you the URL for the curves, just so you can see another dimention od RO.

[Steve]

Sure! The more information the better. I am on a private well and septic. This is good and bad. I don't have to pay for the additional water usage, but I would rather not have so much water going down the drain. I do fill up some buckets and dump it on the lawn, but that is just when I am making a gallon or two. Making water for water changes (5 to 10 gallons) creates a lot more waste water. Plus I probably won't feel like dumping the water outside once there is snow on the ground.
Thanks.

[AquaFx]

Distinguishing Features

For membranes rated from 10 to 120 GDP
Required no electricity
pump powered by energy from brine normally lost to the drain
Improves water quality
Effective for inlet water pressure as low as 30 psi
Fills product tank up to 5 times faster under normal use
Saves 400% of waste water vs. conventional units
Allows smaller capacity membranes
Increases membrane life
Prevents "membrane TDS creep"
Allows greater product tank pressure (90% of feed pressure)
Compact size


Technical Specifications

PUMP DESIGN: "Positive displacement, reciprocating, single action diaphragm, hydraulicall driven.
WEIGHT: 1 lb.
WETTED MATERIALS-PERMEATE SIDE: NSF listed and FDA approved thermoplastic, EPDM.
NON-WETTED MATERIALS: Stainless Steel, Polypropylene.
MOUNTING: Always mount pump with outlet ports up. Mounting clip (ABS) with (2) #10 S.S. screws available.
FITTINGS: Optional Jaco or John Guest straight or elbow.
ERP 1000 Performance Curves

Performance


Data shown in graph above shows strong advantage of Perm pump in tank pressure achieved, time to completely fill the tank, and total amount of water. Perm pump allows 50% greater tank pressure (60 psi vs 40 psi), 18% more water (4989mis vs 4232 ml), in 28% less time (1:13 min vs 1:42min).

The last three lines in the chart show a significant benefit for the Perm Pump in withdrawal of small amounts of water. A glass full (10.6 oz) takes 7 minutes to refill with a Perm system. 6 cups (36.9 oz), enough for a pot of coffee is replenished in 22.5 minutes with the Perm Pump. 1800 ml or 63.5 oz) must be withdrawn from a conventional system to allow the hydraulic shut off valve to reopen allowing the system to refill. It takes 62 min. to replenish 1800 mis, a 176% increase in time to refill.



Data shown in graph above shows strong advantage of Perm pump for low feed water pressures. Perm pump allows slightly more tank pressure (24 psi vs 22 psi), 12% more water (2947mis vs 2636 ml), in less than half the time (2:10 min vs 4:41min). The last three lines in the chart shows a huge benefit for the Perm Pump in withdrawal of small amounts of water. A glass full (10.6 oz) takes 15 minutes to refill with a Perm system. 6 cups (36.9 oz), enough for a pot of coffee is replenished in 35 minutes with the Perm Pump. No data was taken to determine quantity that must be withdrawn from a conventional system to allow the hydraulic shut off valve to reopen allowing the system to refill, although it was observed that the product tank pressure fell to 11 psi before refill commenced. It then took 4 hours 20 min. to completely refill the tank, or 800% increase in time to refill.


OK, I am the kind of person that learns much better and faster by looking at a process work. I am not the strongest data person out there.

The above information is based on running into a pressurized storage tank. Alot of the work we do is with storage at 1 ATM. We do put these pumps on quite a few systems and have had very good sucess. I would love to know your thoughts