Published by aliakbar ghadaksaz
Hi all, Please can you help me remove nitrate in our RO system?
use chemicals? or special membrane?
the inlet and outlet water analysis is in attachment
Dear Aliakbar Ghadaksaz,
Alfred Lipshultz is right that RO is not efficient for nitrate, fluoride and other removal.
You need pre-treatment. This is possible using special mineral sorbents and ion exchange resins.
Please inform the source of the water, the volume of source water per day, the content of fluorides, nitrates and other contaminants in the source water. It is advisable to send a complete analysis of the source water.
Best regards,
Chemist-ecologist Vitalijus Gediminas.
Published by Vitalijus Gediminas
Hard to say sensible things without having wider range of analyses. I assume 'RO first round' means first pass RO permeate? 'RO second round' = second pass RO? If so, why is the second pass RO water dirtier than your first? Strange configuration? You say tube well, suggesting it may be from deeper? If from deep underground you would expect anaerobic water.....which would mean nitrate shouldn't even be there? SO: or you are aerating your well water (maybe to remove iron or manganese or methane?...but I do not see the full range analyses) or it is from a shallow well, or there is pollution entering the watertable of your well. If so: try/drill a deeper well?
Another suggestion that may help: continuous sandfiltration with continuous backwash via air-lift pump, that simultanuously makes the filter bed circulate slowly. Controlled methane dosing into the bed allows limited amount of biomass to remove the NO3- to N2. DynaSand is one tradename (ao Nordic Water), also Paques offers it. Good luck.
Published by Martin P. Pelle, Water Technology Advisor, Engineering & Built Project Utility Team EMEA at Cargill
Something is wrong, either the analyses or the RO membrane. Double check the influent and effluent data. Check the units, are they ug or mg? Is it a low pressure membrane?
Published by Joseph Cotruvo, President at Joseph Cotruvo & Associates, Water , Environment and Public Health
Sorry, but you have 63 ppm TDS, from which the 78 ppm is NO3+ ?
Is it logical? You have to verify the analysis in a serious laboratory..
Published by Apostolos Kavadias, IDRO - APOSTOLOS KAVADIAS
Good Afternoon Mr. Ghadaksaz,
RO is not efficient for nitrate, nitrite, arsenic, fluoride removal. Rejection rate is 45% - 55%.
If this is a smaller RO, you can pretreat with specific anion resin to reduce the nitrate and fluoride.
Another option is to raise pressure to 100 psi (250psi if larger system).
Another option is mixed bed deionization post treatment.
Warmest regards,
FOR THE BEST TASTE IN LIFE
Celebrating 40 Years Pure Excellence
...into another Half Century re-inventing the water industry !
Think Aquathin...AquathinK !
( visit the all new www.aquathin.com )
** AN ISO9001:2000, ISO9001:2008 , ISO9001:2015 QMS REGISTERED / CERTIFIED COMPANY - (IMS 0192, NQA 12635) **
& 2008 PRESIDENT'S E STAR AWARD RECIPIENT ( visit www.aquathin.com/estar2008.pps )
Alfie
Alfred J. Lipshultz
President & CEO
Aquathin Business Center / 950 South Andrews Avenue / Pompano Beach, FL 33069
T 954 781 7777 / F 954 781 7336 /E info@aquathin.com / Skype aquathinhq.alfie
P.S. When responding please continue 'REPLY' to include all previous correspondences on this subject. Like us on 
Published by Alfred Lipshultz, President at Aquathin Corp.