Could you advice on a better (less costly) method for removing chlorides from effluent wastewater? I want to reduce my chlorides concentration to a level below 1500mg/l before discharge through through the municipal sewer. Roughly I've to treat about 700 l/day. The waste will also be treated biologically for removing suilphates and COD (Anaerobic + Aerobic System) so the filtration will be after aeration. I was considering a reverse osmosis process.
Hi. This is a difficult problem because almost all chlorides are soluble. Since this is going to be after secondary treatment and clarification (and possibly sand filtration - lower chance of fouling), I would suggest a desalination technology for the brackish water range. Options would be electrodialysis or capacitative deionization. RO is costly and is typically used for a higher salinity range.
the filtration in secondary treatment after desalination technology(or Oder traitement).
While RO will give you a stream with low chloride, you will still end up with the RO reject stream where the chloride levels are even higher.
I agree reverse osmosis is the good solution, but you must have the solution for retentate/concentrate stream. The another way for water demineralization is ion exchange but in this case you obtain also postregeneration solution to discharge.
RO is actually used for low-TDS ppm as well as for seawater. RO is ideal for your requirement, and for only 700Lpd will be cheap to run. Run a small trial.
to Mr Hopewell Molefe,
Reverse osmosis is the best way to reduce C-1, because Cl-1 are monovalents, you coudn't achieve good results with NF membrane; however, Cl-1 can passes through the membrane in the permeate. please see Donan effect with experiments of prof A. L. Zydney.
Dr Habib Bouzid
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