Waste water treatment process
CA 1269767 C · Owner: Nishihara Environmental Sanitation Research Corp. Ltd. · Inventors: Nishiguchi, Takeshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An improved process for treatment of waste water is proposed in which phosphorus and nitrogen are removed from the waste water by reacting the phosphate ions with iron ions. The waste water to be treated is fed into a tank containing activated sludge. Contact material is arranged in the tank. Non-aeration step and aerating steps are repeated to put the mixture of the waste water and the activated sludge in anaerobic and aerobic conditions respectively. The phosphate ions released from the sludge in the non-aeration step react with iron ions eluted from the iron contact material to form iron phosphates which are insoluble.
Read the whole patent
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 May 29, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 29, 2007.
- 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.