Abstract: The object is to provide a wastewater treatment method and a wastewater treatment system that reduce the total selenium concentration of treated water while reducing cost compared to conventional methods of removing selenium by oxidation. In the wastewater treatment method according to the present disclosure, an iron agent is added to waste water containing selenium and cyanogen to form a first coagulated substance, the first coagulated substance is removed by solid-liquid separation to obtain first treated water, a second iron agent is added to the first treated water, an acid is added to the first treated water to obtain acidic water, an oxidizing agent is added to the acidic water to oxidize the selenium, a coagulant is then added to form a second coagulated substance, and the second coagulated substance is removed by solid-liquid separation to obtain second treated water.
Type:
Application
Filed:
March 11, 2020
Publication date:
June 30, 2022
Applicant:
MITSUBISHI POWER ENVIRONMENTAL SOLUTIONS, LTD.
Inventors:
Takashi Tai, Masaaki Anzai, Naoki Ogawa, Ryosuke Uehara
Abstract: A method for removing selenium according to the present invention comprises: a valence change step of adding an oxidant to a wastewater from a facility that gasifies a fuel containing selenium in a reducing atmosphere, and oxidizing the selenium to change the valence of the selenium, and a solid-liquid separation step of adding a flocculant to the wastewater, forming a floc containing the selenium for which the valence has been changed in the valence change step, and subjecting the floc to solid-liquid separation.
Type:
Grant
Filed:
June 28, 2013
Date of Patent:
February 16, 2021
Assignee:
MITSUBISHI POWER ENVIRONMENTAL SOLUTIONS, LTD.