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January 18, 2017 Demonstration Facilities for gFlow Fluctuation Tracking Type Wastewater Treatement Technology Using DHS Systemh (B-DASH 2017) Start Running

gDemonstration of Flow Fluctuation Tracking Type Wastewater Treatment Technology using DHS*1 System (DHS System)h is adopted by B-DASH Project*2 2017. Japan Sewage Works Agency (JS) has been joining the project as one of the collaborators.

The demonstration project started with the construction of facilities in July 2016, in Susaki City, Kochi Prefecture. The construction work has been completed in January 2017. The experiments will start very soon with data collection by running the facilities.

*1: In DHS(Down-flow Hanging Sponge) system, wastewater travels from top to the bottom of a device filled with water-retentive sponge carriers that keep highly concentrated sludge for biological treatment.

*2: B-DASH Project (Breakthrough by Dynamic Approach in Sewage High Technology Project) has been conducted by Ministry of Land, Infrastructure, Transport, and Tourism (MLIT) of Japan. The Project aims to accelerate R&D of new technologies and their practical applications, enhance costs reduction in sewage works and the production of renewable energy, and facilitate the global presence of Japanese companies in their water business. In B-DASH Project, all demonstrations are carried out as a contract research of National Institute for Land and Infrastructure Management (NILIM.)


Demonstration overview

Name of demonstration: Flow Fluctuation Tracking Type Wastewater Treatment Technology using DHS System
Collaborators: Sanki Engineering Co., Ltd, Tohoku University, National Institute of Technology Kagawa College, JS, Susaki City
Demonstration field: Susaki WWTP in Susaki City, Kochi Prefecture
Treatment capacity: 500 m3/day.
Purpose of the project:
  • Deal with the population decline
  • Reduce LCC
  • Reduce wastewater treatment costs for inflow reduction
  • Easy O&M
  • Stable treatment performance

Overview of the demonstration technology

As figure 1 shows, DHS System, the alternative wastewater treatment Technology of the Conventional Activated Sludge (CAS) Process, is the combination of DHS*2 filter bed filled with sponge carriers and moving bed biological filtration tank.
Wastewater getting through a primary settling tank is given a biological treatment at gDHS filter bedh and then, treated again at a biological filtration tank to effectively remove organic matter.
The features of the technology are as follows.

1. Reduction of LCC by downsizing*3
  • The DHS system can reduce electric power consumption in response to inflow reduction.
  • Enable cost reduction of sludge treatment and disposal in response to reduction of sludge generation
  • Flexible to the change of treatment capacity because of inflow reduction by adjusting the numbers of unit for retrofitting
2. Enable energy saving and effluent quality
The combination of DHS filter bed and biological filtration tank is more energy saving than CAS Process and produces effluent with equivalent quality to CAS Process.

3. Easy O&M
  • Few numbers of maintenance items
  • Few numbers of equipment
4. Utilize existing facilities
A DHS filter bed and a biological filtration tank can be installed inside the existing reactor.

*3: Downsizing is to reduce the capacity of treatment facilities.


comparison between DHS system and CAS process detail of DHS filter bed detail of biofilm filtration tank location of Susaki WWTP demonstration facilities