Nitrogen removal method, nitrification-reaction promoting agent for water treatment, and water treatment method

Abstract

Disclosed herein is a method for removing nitrogen from water, which makes it possible to omit equipment for controlling the supply of a carbon source (hydrogen donor), equipment for post-processing a carbon source (hydrogen donor), and circulation equipment and to prevent an increase in the size of a system. The method includes adding a solid material containing a biodegradable resin as a hydrogen donor to one water system in which bacteria cells having an ability to decompose a biodegradable resin, bacteria cells having nitrification capabilities, and bacteria cells having denitrification capabilities live together to allow a nitrification reaction and a denitrification reaction coexist in the water system. Also disclosed herein is a nitrification-reaction promoting agent for water treatment including 20 wt % or more of a biodegradable resin and having a specific gravity of more than 1 g/cm3.

1 . A nitrification-reaction promoting agent for water treatment comprising 20 wt % or more of a biodegradable resin and having a specific gravity of more than 1 g/cm 3 . 
     
     
         2 . The nitrification-reaction promoting agent of  claim 1 , wherein the biodegradable resin is at least one selected from the group consisting of a poly-3-hydroxyalkanoate, polybutylene succinate, and polylactic acid. 
     
     
         3 . The nitrification-reaction promoting agent of  claim 1 , wherein the biodegradable resin is a biodegradable polyester. 
     
     
         4 . The nitrification-reaction promoting agent of  claim 3 , wherein the biodegradable polyester is a biodegradable aliphatic polyester. 
     
     
         5 . The nitrification-reaction promoting agent of  claim 4 , wherein the biodegradable aliphatic polyester is a poly-3-hydroxyalkanoate. 
     
     
         6 . The nitrification-reaction promoting agent of  claim 5 , wherein the poly-3-hydroxyalkanoate is a poly-3-hydroxybutyrate homopolymer or copolymer. 
     
     
         7 . The nitrification-reaction promoting agent of  claim 1 , wherein the nitrification-reaction promoting agent further comprises a hydrogen donor different form the biodegradable resin. 
     
     
         8 . The nitrification-reaction promoting agent of  claim 7 , wherein the hydrogen donor is starch. 
     
     
         9 . The nitrification-reaction promoting agent of  claim 1 , further comprising a non-biodegradable resin. 
     
     
         10 . The nitrification-reaction promoting agent of  claim 9 , wherein the non-biodegradable resin is polyethylene or polypropylene, a solid fat, or a wood powder. 
     
     
         11 . The nitrification-reaction promoting agent of  claim 1 , wherein the nitrification-reaction promoting agent is in the form of powder, granules, or pellets. 
     
     
         12 . The nitrification-reaction promoting agent of  claim 1 , wherein an amount of the biodegradable resin in the nitrification-reaction promoting agent is 20 wt % or more. 
     
     
         13 . The nitrification-reaction promoting agent of  claim 1 , wherein an amount of the biodegradable resin in the nitrification-reaction promoting agent is 30 wt % or more. 
     
     
         14 . The nitrification-reaction promoting agent of  claim 1 , wherein an amount of the biodegradable resin in the nitrification-reaction promoting agent is 40 wt % or more. 
     
     
         15 . The nitrification-reaction promoting agent of  claim 1 , wherein the nitrification-reaction promoting agent comprises less than 80 wt % of an additional material comprising starch, a non-biodegradable resin, a solid fat, and a wood powder. 
     
     
         16 . The nitrification-reaction promoting agent of  claim 1 , wherein the specific gravity of the nitrification-reaction promoting agent is 1.1 g/cm 3  or more. 
     
     
         17 . The nitrification-reaction promoting agent of  claim 1 , wherein the specific gravity of the nitrification-reaction promoting agent is 1.2 g/cm 3  or more. 
     
     
         18 . The nitrification-reaction promoting agent of  claim 1 , wherein the specific gravity of the nitrification-reaction promoting agent is 3 g/cm 3  or less. 
     
     
         19 . The nitrification-reaction promoting agent of  claim 1 , wherein the specific gravity of the nitrification-reaction promoting agent is 2.5 g/cm 3  or less. 
     
     
         20 . The nitrification-reaction promoting agent of  claim 1 , wherein the specific gravity of the nitrification-reaction promoting agent is 2 g/cm 3  or less.