Bacillus subtilis (Bacillus subtilis) BN1001 bacteria (Accession No. FERM P-11132) and natto (. Bacillus subtilis var natto) composition containing as an active ingredient; waste water comprising a biological treatment tank for biologically treated wastewater a processing system, in the biological treatment tank containing BN1001 bacteria and Bacillus natto, waste water treatment system; draining a biologically treated waste water treatment method for, adding BN1001 bacteria and Bacillus natto to the drainage comprising the step, waste water treatment method; comprising the step of the malodor contacting BN1001 bacteria and Bacillus natto, deodorizing method; Bacillus subtilis and the carrier was supported the Bacillus natto; containing the carrier in the biological treatment tank, the waste water processing system; comprising the step of adding the carrier to the wastewater discharge Processing method; a batch waste water treatment method, biological treatment tank comprises a carrier, batch waste water treatment method.バチルス・サブチリス(Bacillus subtilis)BN1001菌(受託番号 FERM P-11132)及び納豆菌(Bacillus subtilis var. natto)を有効成分として含有する組成物;排水を生物学的に処理する生物処理槽を備える排水処理システムであって、前記生物処理槽中にBN1001菌及び納豆菌を含む、排水処理システム;排水を生物学的に処理する排水処理方法であって、前記排水にBN1001菌及び納豆菌を添加する工程を備える、排水処理方法;悪臭源にBN1001菌及び納豆菌を接触させる工程を備える、消臭方法;バチルス・サブチリス及び納豆菌を担持させた担体;生物処理槽中に前記担体を含む、排水処理システム;排水に前記担体を添加する工程を備える、排水処理方法;回分式排水処理方法であって、生物処理槽が、前記担体を含む、回分式排水処理方法。