Calcium Polysulfide to remove nitrates
Calcium Polysulfide to remove nitrates
(OP)
I have a waste stream containing 400ppm NO3 from rinse tanks in a nitric acid pickling facility. A contractor has suggested using calcium polysulfide to remove nitrates before sending the water to a collection area for pH adjustment which will then go to the POTW for disposal. Is this a common treatment option? What is the price for the calcium polysulfide?





RE: Calcium Polysulfide to remove nitrates
Does this sound like a solicit - can't help it - ther is no literature or sites I can recommend you too to investigate.
regards -
Dave/Aquatic Technologies
RE: Calcium Polysulfide to remove nitrates
Plenty of websites: do a search for electrocoagulation. Get a sales rep to bring a demo unit to test on your wastestream(s).
RE: Calcium Polysulfide to remove nitrates
RE: Calcium Polysulfide to remove nitrates
http://www.powellwater.com/treat-potable.htm,
but I'm not sure of the exact chemistry. Metal surfaces can catalyze the reduction of nitrate, so there may be breakdown occurring on the plates. A study below reports on treatment of nitrate, but [the abstract] doesn't mention nitrite.
Journal of Hazardous Materials
Volume 89, Issue 1 , 4 January 2002, Pages 83-94
Removal of nitrate from water by electroreduction and electrocoagulation
"The aim of this work was to investigate the feasibility of the removal of nitrate from water by applying electrochemical methods such as electroreduction and electrocoagulation. In electroreduction, removal of nitrate to an allowable concentration has been accomplished at the pH range of 5–7 with energy consumption value of 1×10-3 kWh/g. In electrocoagulation, an allowable concentration of nitrate has been achieved at the pH range of 9–11 with energy consumption value of 0.5×10-4 kWh/g. Full removal of nitrate was also possible but with higher energy consumptions for these two methods."
RE: Calcium Polysulfide to remove nitrates
The claims in the paper above sound quite promising (i.e. 0.001 kWh/g of nitrate would represent a very low energy input per unit volume). However, I would doubt the energy input requirement is constant with mass removal and independent of influent concentration. If you have the complete paper and can e-mail it to me at martinsmoltenmetal@hotmail.com I'd be very interested!