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Alternative uses for high TDS waste from RO system?


Q. I am working as a ETP in charge in a private oil & gas company in India. We have a small treatment plant to treat the effluent before safe disposal. We are getting all the parameters except Total dissolved solids well within the limits given by state governing body at the outlet of plant.
Now we are thinking of Reverse Osmosis plant to fix the high TDS problem. We are getting around 7000 ppm of TDS at the outlet of ETP.
In RO system there will be two outlet streams: one is clear pure water & another is concentrated stream having high TDS.
My question is what are the possible methods for disposal of this concentrated stream.

Patel Jayesh Manaharbhai
- Ahmedabad, Gujarat, India


A. What is the TDS measurement before your treatment? If you are adding TDS by treatment then you should examine that process. Chances are, your reject water is worthless. The most effective way to dispose of high TDS water is a deep well. The next is probably evaporation. But the best is to prevent the TDS to begin with.

paul morkovsky
Paul Morkovsky
- Shiner, Texas, USA


A. Hi
The various methods of disposal of 7000 ppm TDS RO reject is as follows.
1. watering plants.
2. send to sewage disposal.
3. can reuse by passing through softener bed.
4. you can also evaporate , condensate can be reused, but costly, will lead to scaling/fouling.
5. you can also use this High TDS water for toilet flushing.

Hope this may help you.

Panjala Mukesh
     fashion jewelry mfgr.
Hyderabad, India


A. My company uses a phased approach to this problem - We build the RO system with multiple passes, using interstage pumps and membranes designed for the high TDS water.

Then, to get rid of the very high TDS waste stream this creates, use a precipitation stage and clarifier to settle the solids, and put the water back into the front of the process.

You should be able to achieve 95%+ usage of the water.

Jeff Watson
- Pearland, Texas


Q. Hello.

I am a student of M.Sc. Environmental Science. I am doing a project on Water Quality of Gujarat and ways to provide safe water to the rural areas. Here these villages have these RO plants installed. Now there are mainly 2 problems coming out of this:

1. it gives of 60% of the waste water which contains high TDS and also the uptake of ground water is high which decreases the water table.

2. Now what to do with this reject water from these RO plants?

Will wait for your reply.

Urvish Ishwarbhai Vadgama
ISTAR college, V.V. Nagar, Gujarat, India - Vallabh Vidhya Nagar, Gujarat, India.


A. Hi Urvish. Quicker progress on your studies will surely be made if you are able to express your questions in terms of what has already been said, and build on it, rather than starting over. Mssrs. Morkovsky, Mukesh, and Watson have demonstrated their knowledge of this subject, but I doubt that you will win points with them by blowing off the effort they've already put into this page :-)

Please try to synthesize a proposed answer to your questions from what they have already said, and then ask if your idea sounds promising, okay? Good luck!

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

December 29, 2010

Q. Dear sir, we are facing high TDS in our area; we want to convert this water for drinking. The TDS limit is 5000 hardness 800 ppm --so could you please give me right RO membrane for high TDS?


July 24, 2012

Q. Hello

In one of the projects I am working on for an automobile industry, we have 70 cubic meters of RO reject effluent to be reused/ disposed off. This contains around 4000 ppm of Total Dissolved Solids.

I would appreciate being enlightened about the options available and their viability -- apart from deep well injection, evaporation, disposal by dilution in a sewage stream. Can this be used for flushing of toilets either directly or after pH adjustment, coagulation, precipitation followed by settling and filtration?


Komal Dixit
engineering - Mumbai, India

November 29, 2012

Q. Dear Sir,
We want to know how we treat the ETP (effluent treatment plant) water and then it convert it into R.O. water. What can I do for this treatment and what chemical we use for treatment. This is chemical industries waste water. Please give me reply.

Vikram Singh
biotech - Bhiwadi, Rajasthan, India

November 29, 2012

A. Sorry for the difficulties, Vikram, but I don't know what question you are asking...

Are you asking for a generalized ETP regimen to handle all undescribed volumes of unknown wastes under unknown conditions? That subject fills whole aisles in technical libraries :-)

Or are you saying that you've already treated the waste, and now you want to put this undescribed treated waste into an R.O. system to pull some pure water out of it, to be used for some undescribed purpose?

Sorry, but if you can clarify and limit your question we may be able to help, whereas if you want to learn the whole subject of chemical and R.O. treatment you would need to read a book or take a course. Please clarify. Thanks.


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

June 30, 2014appended

Q. Can someone throw light on usage of waste R.O Water or how waste R.O water can be used somewhere to conserve the water resource?

Manish Chandra
- N.Delhi, India
  ^- Privately contact this inquirer -^

June 2014

A. Hi Manish. As you see, this question has been addressed before in this forum, so we appended your inquiry to it. If the previous answers aren't sufficient for you, please expand upon them. Thanks.


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

October 6, 2014

Q. Hi Ted

To be a little specific on the previous question. For one of my clients I am planning to propose a multi-stage RO system to treat their raw water (ground water) for process. The inlet water TDS is 1700 ppm, the expected volume of reject is 5 KLD at a TDS of around 25000 to 30000 ppm. I understand that leather industry uses water with high salt content for pickling but there will be chemicals added in the water stream for pH adjustment, biocide, anti-scalant, etc. The question is can this be used in the leather industry or can you recommend if there is any other industry which will find use of this high concentration of salt water?

Wilson Dhanaraj
consultancy - Chennai, Tamilnadu, India

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