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News Release
04.01.2019

Handover Completed of Nitrogen Removal Facility Using Anammox Bacteria
~Osaka City, Dehydration Separated Liquid Treatment Facility at the Hirano Sewage Treatment Plant ~

METAWATER Co., Ltd. (President: Yasushi Nakamura, Headquarters: Chiyoda-ku), entrusted by Osaka City, has been carrying out the design, construction, and operation management of a dehydration separated liquid treatment facility, which uses anammox bacteria to remove ammonia nitrogen in dehydration separated liquid at the Hirano sewage treatment plant (hereinafter “Facility”). Today, the Facility was handed over to Osaka City.
 
Osaka City has been promoting initiatives to reduce wastewater sludge. However, high concentrations of ammonia nitrogen were generated in the digestive process for promoting sludge decomposition, which created dehydration separated liquid containing high concentrations of ammonia nitrogen (1,000 mg/L) as wastewater in the succeeding dewatering process. One of the causes of the eutrophication of rivers and oceans, nitrogen is also subject to effluent control (25 mg/L), and efficiently removing concentrated ammonia nitrogen contained in dehydration separated liquid has been an issue.

Consequently, the Hirano sewage treatment plant, where digestive treatment of sludge had been launched, decided to construct a new dehydration separated liquid treatment facility adopting a nitrogen removal method, which uses the anammox reaction with a biological process. The Facility will be Japan’s first sewage treatment facility to use the nitrogen removal reaction with anammox bacteria.



 

Anammox Reaction

The anammox reaction is a reaction which directly transforms ammonia nitrogen (NH4+) and nitrite nitrogen (NO2-) into nitrogen gas (N2) through the actions of anammox bacteria, which are anaerobic (state in which oxygen is absent) autotrophic bacteria (bacteria not requiring organic substance to reproduce). It is a relatively new biological nitrogen transformation reaction discovered by a research group at the Delft University of Technology in the 1990s. Compared to the nitrification and denitrification method, which is a common method for removing nitrogen, nitrogen is removed efficiently, making it possible to reduce expenses for electric power and chemicals.



Cost Reduction Effects of Introducing the Anammox Method (Comparison with nitrification and denitrification method)

Compared to the previous nitrification and denitrification method, the anammox method has the characteristics of: (1) requiring less oxygen and equipment such as blowers and energy; (2) not requiring chemical treatment of organic substances because they are not needed in the reaction; and, (3) producing little excess sludge (generated sludge volume). As a result of joint research with Osaka City, its applicability to sewage treatment plants in Osaka City was confirmed.



Awarded The 11th Minister of Land, Infrastructure, Transport and Tourism Award (Circulation Path Sewage Works Award)*

In September 2018, the Facility was recognized as an initiative that contributes to creating new value for sewage works and was awarded The 11th Minister of Land, Infrastructure, Transport and Tourism Award (Circulation Path Sewage Works Award) under the Innovation Division.
 
* Definition of Circulation Path Sewage Works Award
The Circulation Path Sewage Works Award is an award given by the Minister of Land, Infrastructure, Transport and Tourism created in 2008. It commends outstanding initiatives taken on the basis of “circulation path sewage works,” a concept adopted for 21st Century sewage works to create a healthy water environment, and recycle resources and energy. By commending outstanding cases and broadly disseminating them, the award recognizes the winners’ achievements and aims to have similar initiatives taken by many other organizations and to realize “circulation path sewage works” nationwide.



Overview of Project

Target Facility

Dehydration separated liquid treatment facility

Main Business Activities

Design, construction, and operation management of dehydration separated liquid treatment facility

Capacity of Facility

Quantity of treated wastewater        1,350 m3/day

Capacity of nitrogen removal                80% or more (total nitrogen 1,000 mg/L→200 mg/L)

Project Period

Design                                   From March 19, 2014 to October 31, 2014
Construction                          From November 1, 2014 to March 31, 2017
Operation Management          From April 1, 2017 to March 31, 2019

Treatment Method

Nitrogen removal method using anammox bacteria

Name of Contractor

METAWATER Co., Ltd.

Facility Location

2-6-69 Kamikita, Hirano-ku, Osaka City (within Hirano sewage treatment plant site)

 

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