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Expired Canadian patentCanada

Chemical waste water treatment method

CA 1085979 A · Owner: Carvalho, Rocky J. · Inventors: Horvath, Peter J.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Abstract of Disclosure A method of treating domestic, commercial or industrial waste water which includes the steps of mixing the waste water with a coagulant aid so as to bring the pH of the mixture to within a range of about 9.0-10.5 and thereafter, adding precipitating agents in at least two successive steps so as to lower the pH of the mixture by about one unit for each step and thereby precipitate solids therefrom until the mixture is approximately neutral. After the addition of each precipitating agent, the precipitated solids are separated from the waste water effluent before the next succeeding precipitating agent is added. Preferably two such successive precipitation steps are …

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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

  • Granted September 16, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 16, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 19, 1977
GrantedSeptember 16, 1980
Term endedSeptember 16, 1997
Patent numberCA 1085979 A
Classification (IPC)C02F1/78 +2 more

Timeline

Timeline From CIPO dates

1978198019821984198619881990199219941996Application filedApril 19, 1977Patent grantedSep 16, 1980Term endedSep 16, 1997

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.