Hitachi Plant Technologies, Ltd.

Hitachi, Ltd.

Yuya Kimura

Kazuichi Isaka

Tatsuo Sumino

Shinichi Yoshikawa

Hajime Ikuta

Shoko Miyamae

Provided are an immobilization carrier, a polyether compound used for production thereof and a method for producing the carrier. The immobilization carrier have both excellent strength and toughness while a content of a polymer forming hydrous gel is suppressed, The immobilization carrier includes a polymer having a repeated unit provided with a bisphenol group and a polyoxyalkylene group bonded to the bisphenol group. The polyoxyalkylene group is formed via copolymerization between an oxyethylene group and an oxyalkylene group with 3 or more carbon atoms and optionally having a substituent. A method for producing the immobilization carrier includes the step of preparing hydrous gel via polymerizing a polyether compound in an aqueous solution. The polyether compound includes a bisphenol group, a polyoxyalkylene group and a polymerizable group. The immobilization carrier may be applied to a microorganism immobilization carrier used for treating wastewater.

Immobilizing carrier, polyether compound used for producing same and method for producing immobilization carrier

Provided is a method for treating ammoniacal nitrogen in wastewater performed via biologically oxidizing ammoniacal nitrogen, and producing nitrite nitrogen and nitrate nitrogen at a desired rate. In the method, ammoniacal nitrogen is oxidized by bacterial sludges to produce at least either of nitrite nitrogen and nitrate nitrogen. Specifically, the method includes an inactivating treatment step of treating the bacterial sludges with an inactivating operation via sterilizing bacteria or causing bacteriostasis, and a nitrifying treatment step of oxidizing the ammoniacal nitrogen by the bacterial sludges thus treated in the inactivating operation. Production amounts of the nitrite nitrogen and the nitrate nitrogen are controlled by adjusting biomass of the bacterial sludges to be treated in the inactivating operation, and/or a time interval between the inactivating operations each repeatedly performed in combination with the nitrifying treatment step.

Method for treating ammoniacal nitrogen in wastewater

An aspect of the present invention provides a wastewater treatment method for treating wastewater containing ammonium nitrogen, including the steps of: oxidizing the ammonium nitrogen in the wastewater to nitrite with nitrifying bacteria in a treatment tank in which the nitrifying bacteria and anaerobic ammonium-oxidizing bacteria having a half-saturation constant of 6.1 mgN/L or more with respect to nitrite coexist; and denitrifying the nitrite formed through the oxidation of the ammonium nitrogen, with the anaerobic ammonium-oxidizing bacteria in the treatment tank, while using the ammonium nitrogen contained in the wastewater as a hydrogen donor. The method employs the anaerobic ammonium-oxidizing bacteria that can maintain the denitrification activity even under a condition in which the amount of dissolved oxygen is large, consequently can easily maintain the activities of both of the nitrifying bacteria and the anaerobic ammonium-oxidizing bacteria which coexist in the same treatment tank, and can rapidly perform wastewater treatment.

Wastewater treatment method and wastewater treatment apparatus

A nitrification carrier having made nitrifying bacteria dominant therein and a denitrification carrier having made anaerobic ammonium-oxidizing bacteria dominant therein are mixed in a treatment tank. Both of a nitrification reaction with the nitrification carrier and a denitrification reaction with denitrification carrier are allowed to proceed in the treatment tank to decompose ammonium nitrogen in wastewater to nitrogen gas. The ratio of the bacterial loads of the nitrifying bacteria and the anaerobic ammonium-oxidizing bacteria can be easily controlled by immobilizing the nitrifying bacteria and the anaerobic ammonium-oxidizing bacteria on different carriers from each other (nitrification carrier and denitrification carrier) and by controlling the volume ratio (ratio of the feeding amounts) of the nitrification carrier and the denitrification carrier.

A wastewater treatment method for treating wastewater containing ammonium nitrogen, includes the steps of: charging an unacclimated denitrification carrier containing anaerobic ammonium-oxidizing bacteria into a treatment tank; charging an unacclimated nitrification carrier containing nitrifying bacteria into the treatment tank; acclimating the unacclimated denitrification carrier in the treatment tank under an anaerobic condition; acclimating the unacclimated nitrification carrier in the treatment tank under an aerobic condition, after having acclimated the denitrification carrier; nitriting the ammonium nitrogen in the wastewater to generate nitrite with the acclimated nitrification carrier; and denitrifying the nitrite generated by nitriting the ammonium nitrogen with the acclimated denitrification carrier, while using the ammonium nitrogen in the wastewater as a hydrogen donor.

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Tokyo, Japan

Yuya Kimura