Method for treating selenium-containing wastewater and apparatus for carrying out the method
CA 2249433 A1 · Owner: Organo Corporation · Inventors: Nishizawa, Hideo; Yano, Rie
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A selenium-containing waste water is treated by biological treating means (6) chemical treating means (12), and filtration means (14) in a successive manner. In the biological treating means (6) hexavalent selenate ions and/or , tetravalent selenite ions (soluble selenium) present in untreated water (16) is reduced by anaerobic biological treatment to selenium as a simple substance; thereby insolubilizing and removing the soluble selenium. In the chemical treating means (12), for example a metal salt capable of reacting , with the soluble selenium to generate an insoluble selenium compound is added to the water after the treatment by the biological treating means (6) to insolubilize …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed March 18, 1997. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended March 18, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 18, 2019.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.